Oxygen therapy

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Oxygen piping and regulator, for oxygen therapy, mounted on the wall of an ambulance

Oxygen therapy is the administration of oxygen as a medical intervention, which can be for a variety of purposes in both chronic and acute patient care. Oxygen is essential for cell metabolism, and in turn, tissue oxygenation is essential for all normal physiological functions.[1]

High blood and tissue levels of oxygen can be helpful or damaging, depending on circumstances and oxygen therapy should be used to benefit the patient by increasing the supply of oxygen to the lungs and thereby increasing the availability of oxygen to the body tissues, especially when the patient is suffering from hypoxia and/or hypoxaemia.

Oxygen can be administered in a number of ways, including specific treatments at raised air pressure, such as hyperbaric oxygen therapy.

Contents

[hide]

y 1 Indications for use o 1.1 Use in chronic conditions o 1.2 Use in acute conditions y 2 Storage and sources y 3 Delivery o 3.1 Supplemental oxygen o 3.2 High flow oxygen delivery o 3.3 Positive pressure delivery o 3.4 As a drug delivery route o 3.5 Filtered oxygen masks y 4 Contraindications and cautions y 5 Negative effects y 6 Oxygen therapy while on aircraft y 7 See also y 8 References y 9 External links

[edit] Indications for use

Oxygen is used as a medical treatment in both chronic and acute cases, and can be used in hospital, pre-hospital or entirely out of hospital, dependant on the needs of the patient and the views of the medical professional advising.

[edit] Use in chronic conditions

A common use of supplementary oxygen is in patients with chronic obstructive pulmonary disease (COPD), a common long term effect of smoking, who may require additional oxygen to breathe either during a temporary worsening of their condition, or throughout the day and night. It is indicated in COPD patients with PaO2 ” 55mmHg or SaO2 ” 88% and has been shown to increase lifespan.[2]

[edit] Use in acute conditions

Oxygen is widely used in emergency medicine, both in hospital and by emergency medical services or advanced first aiders.

In the pre-hospital environment, high flow oxygen is definitively indicated for use in resuscitation, major trauma, anaphylaxis, major haemorrhage, shock, active convulsions and hypothermia.[1][3]

It may also be indicated for any other patient where their injury or illness has caused hypoxaemia, although in this case oxygen flow should be moderated to achieve target oxygen saturation levels, based on pulse oximetry (with a target level of 94-98% in most patients, or 88- 92% in COPD patients).[1]

For personal use, high concentration oxygen is used as home therapy to abort cluster headache attacks, due to its vaso-constrictive effects.[4] [edit] Storage and sources

Gas canisters containing oxygen to be used at home. When in use a pipe is attached to the top of the can and then to a mask that fits over the patient's nose and mouth.

A home oxygen concentrator in situ in an Emphysema patient's house. The model shown is the DeVILBISS LT 4000.

Oxygen can be separated by a number of methods, including chemical reaction and fractional distillation, and then either used immediately or stored for future use. The main types sources for oxygen therapy are:

1. Liquid storage - Liquid oxygen is stored in chilled tanks until required, and then allowed to boil (at a temperature of 90.188 K (í182.96 °C)) to release oxygen as a gas. This is widely used at hospitals due to their high usage requirements, but can also be used in other settings. See Vacuum Insulated Evaporator for more information on this method of storage. 2. Compressed gas storage - The oxygen gas is compressed in a gas cylinder, which provides a convenient storage, without the requirement for refrigeration found with liquid storage. See Oxygen cylinder manifold for more information. 3. Instant usage - The use of an electrically powered oxygen concentrator[5] or a chemical reaction based unit[6] can create sufficient oxygen for a patient to use immediately, and these units (especially the electrically powered versions) are in widespread usage for home oxygen therapy and portable personal oxygen, with the advantage of being continuous supply without the need for additional deliveries of bulky cylinders. [edit] Delivery Various devices are used for administration of oxygen, from whichever source. In most cases, the oxygen will first pass through a pressure regulator, used to control the high pressure of oxygen delivered from a cylinder (or other source) to a lower pressure. This lower pressure is then controlled by a flowmeter, which may be preset or selectable, and this controls the flow in a measure such as litres per minute (lpm). The typical flowmeter range for medical oxygen is between 0 and 25 lpm.

[edit] Supplemental oxygen

A patient wearing a simple face mask.

Many patients require only a supplementary level of oxygen in the room air they are breathing, rather than pure or near pure oxygen,[7] and this can be delivered through a number of devices dependant on the situation, flow required and in some instances patient preference.

A nasal cannula (NC) is a thin tube with two small nozzles that protrude into the patient's nostrils. It can only comfortably provide oxygen at low flow rates, 0.25-6 litres per minute (LPM), delivering a concentration of 24-40%.

There are also a number of face mask options, such as the simple face mask, often used at between 5 and 15 LPM, with a concentration of oxygen to the patient of between 28% and 50%. This is closely related to the more controlled air-entrainment masks, also known as Venturi masks, which can accurately deliver a predetermined oxygen concentration to the trachea up to 40%.

In some instances, a Partial rebreathing mask can be used, which is based on a simple mask, but featuring a reservoir bag, which increases the provided oxygen rate to 40-70% oxygen at 5 to 15 LPM. [edit] High flow oxygen delivery

A tightly sealed aviators oxygen mask

In cases where the patient requires a flow of up to 100% oxygen, a number of devices are available, with the most common being the non-rebreather mask (or reservoir mask), which is similar to the partial rebreathing mask except it has a series of one-way valves preventing exhaled air from returning to the bag. There should be a minimum flow of 10 L/min. The delivered FIO2 of this system is 60-80%, depending on the oxygen flow and breathing pattern.[8],[9]

In specialist applications such as aviation, tight fitting masks can be used, and these also have applications in anaesthesia, carbon monoxide poisoning treatment and in hyperbaric oxygen therapy

[edit] Positive pressure delivery

Patients who are unable to breathe on their own will require positive pressure to move oxygen in to their lungs for gaseous exchange to take place. Systems for delivering this vary in complexity (and cost), starting with a basic pocket mask adjunct which can be used by a basically trained first aider to manually deliver artificial respiration with supplemental oxygen delivered through a port in the mask.

Many emergency medical service and first aid personnel, as well as hospitals, will use a bag- valve-mask (BVM), which is a maleable bag attached to a face mask (or invasive airway such as an endotracheal tube or laryngeal mask airway), usually with a reservoir bag attached, which is manually manipulated by the healthcare professional to push oxygen (or air) in to the lungs. This is only procedure allowed for initial treatment of cyanide poisoning in the UK workplace[10].

Automated versions of the BVM system, known as a resuscitator or pneupac can also deliver measured and timed doses of oxygen direct to patient through a facemask or airway. These systems are related to the anaesthetic machines used in operations under general anaesthesia that allows a variable amount of oxygen to be delivered, along with other gases including air, nitrous oxide and inhalational anaesthetics.

[edit] As a drug delivery route Oxygen therapy can also be used as part of a strategy for delivering drugs to a patient, with the usual example of this being through a nebulizer mask, which delivers nebulizable drugs such as salbutamol or epinephrine into the airways by creating a vapor-mist from the liquid form of the drug.

[edit] Filtered oxygen masks

Filtered oxygen masks have the ability to prevent exhaled, potentially infectious particles from being released into the surrounding environment. These masks are normally of a closed design such that leaks are minimized and breathing of room air is controlled through a series of one-way valves. Filtration of exhaled breaths is accomplished either by placing a filter on the exhalation port, or through an integral filter that is part of the mask itself. These masks first became popular in the Toronto (Canada) healthcare community during the 2003 SARS Crisis. SARS was identified as being respiratory based and it was determined that conventional oxygen therapy devices were not designed for the containment of exhaled particles.[11],[12],[13] Common practices of having suspected patients wear a surgical mask was confounded by the use of standard oxygen therapy equipment. In 2003, the HiOx80 oxygen mask was released for sale. The HiOx80 mask is a closed design mask that allows a filter to be placed on the exhalation port. Several new designs have emerged in the global healthcare community for the containment and filtration of potentially infectious particles. Other designs include the ISO-O2 oxygen mask,the Flo2Max oxygen mask, and the O-Mask. The use of oxygen masks that are capable of filtering exhaled particles is gradually becoming a recommended practice for pandemic preparation in many jurisdictions.

Because filtered oxygen masks use a closed design that minimizes or eliminates inadvertent exposure to room air, delivered oxygen concentrations to the patient have been found to be higher than conventional non-rebreather masks, approaching 99% using adequate oxygen flows. Because all exhaled particles are contained within the mask, nebulized medications are also prevented from being released into the surrounding atmosphere, decreasing the occupational exposure to healthcare staff and other patients. [edit] Contraindications and cautions

Oxygen should never be used in explosive environments, and its use is cautioned against when there is a risk of sparks or materials combusting as oxygen accelerates combustion. Smoking during oxygen therapy is a fire hazard and a danger to life and limb, especially with home oxygen if compliance is poor.[14] Oxygen may worsen the effects of paraquat poisoning and is therefore contraindicated in such cases. Oxygen therapy is not recommended for patients who have suffered pulmonary fibrosis or other lung damage resulting from Bleomycin treatment. [edit] Negative effects

Although most EMS jurisdictions hold that oxygen should not be withheld from any patient, there are certain situations in which oxygen therapy can have a negative impact on a patient¶s condition. Oxygen has vasoconstrictive effects on the circulatory system, reducing peripheral circulation and was once thought to potentially increase the effects of stroke. However, when additional oxygen is given to the patient, additional oxygen is dissolved in the plasma according to Henry's Law. This allows a compensating change to occur and the dissolved oxygen in plasma supports embarrassed (oxygen-starved) neurons, reduces inflammation and post-stroke cerebral edema. Since 1990, hyperbaric oxygen therapy has been used in the treatments of stroke on a worldwide basis. In rare instances, hyperbaric oxygen therapy patients have had seizures. However, because of the aforementioned Henry's Law effect of extra available dissolved oxygen to neurons, there is usually no negative sequel to the event. Such seizures are generally a result of oxygen toxicity,[15][16] although hypoglycemia may be a contributing factor, but the latter risk can be eradicated or reduced by carefully monitoring the patient's nutritional intake prior to oxygen treatment.

High levels of oxygen given to infants causes blindness by promoting overgrowth of new blood vessels in the eye obstructing sight. This is Retinopathy of prematurity (ROP). Administration of high levels of oxygen in patients with severe emphysema and high blood carbon dioxide reduces respiratory drive, which can precipitate respiratory failure and death.

Care needs to be exercised in patients with chronic obstructive pulmonary disease, especially in those known to retain carbon dioxide (type II respiratory failure) who lose their respiratory drive and accumulate carbon dioxide if administered oxygen in moderate concentration. However the risk of the loss of respiratory drive are far outweighed by the risks of withholding emergency oxygen, and therefore emergency administration of oxygen is never contraindicated.

Oxygen first aid has been used as an emergency treatment for diving injuries for years.[17] The success of recompression therapy as well as a decrease in the number of recompression treatments required has been shown if first aid oxygen is given within four hours after surfacing.[18] There are suggestions that oxygen administration may not be the most effective measure for the treatment of DCI/DCS and that heliox may be a better alternative.[19] Recompression in a hyperbaric chamber with the patient breathing 100% oxygen is the standard hospital and military medical response to decompression illness and decompression sickness.[17][20][21]

Oxygen should never be given to a patient who is suffering from paraquat poisoning unless they are suffering from severe respiratory distress or respiratory arrest, as this can increase the toxicity. (Paraquat poisoning is rare - for example 200 deaths globally from 1958-1978)[22] [edit] Oxygen therapy while on aircraft

In the United States, most airlines restrict the devices allowed on board aircraft. As a result passengers are restricted in what devices they can use. Some airlines will provide cylinders for passengers with an associated fee. Other airlines allow passengers to carry on approved portable concentrators. However the lists of approved devices varies by airline so passengers need to check with any airline they are planning to fly on. Passengers are generally not allowed to carry on their own cylinders. In all cases, passengers need to notify the airline in advance of their equipment. asal cannula

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Jump to: navigation, search

Illustration of a nasal cannula

The nasal cannula (NC) is a device used to deliver supplemental oxygen to a patient or person in need of extra oxygen. This device consists of a plastic tube which fits behind the ears, and a set of two prongs which are placed in the nostrils. Oxygen flows from these prongs.[1] The nasal cannula is connected to an oxygen tank, a portable oxygen generator, or a wall connection in a hospital via a flowmeter. The nasal cannula carries 1±6 litres of oxygen per minute. There are also infant or neonatal nasal cannulas which carry less than one litre per minute; these also have smaller prongs. The oxygen fraction provided to the patient ranges roughly from 24% to 35%.

The nasal cannula was invented by Wilfred Jones and patented in 1949 by his employer, BOC.

Contents

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y 1 Applications y 2 See also y 3 References y 4 External links [edit] Applications

A nasal cannula can be used wherever small amounts of supplemental oxygen without rigid control of respiration are required, such as in oxygen therapy. It can only provide oxygen at low flow rates²up to 6 litres per minute (L/min)²delivering an oxygen concentration of 28±44%. Rates above 6 L/min can result in discomfort to the patient, drying of the nasal passages, and possibly nose bleeds (epistaxis).

The nasal cannula is often used in elderly patients or patients who can benefit from oxygen therapy but do not require it to self respirate. These patients do not need oxygen to the degree of wearing a non-rebreather mask. It is especially useful in those patients where vasoconstriction could negatively impact their condition, such as those suffering from strokes.

It may also be used by pilots and passengers in small, unpressurized aircraft that do not exceed certain altitudes. The cannula provides extra oxygen to compensate for the lower oxygen content available for breathing at the low ambient air pressures of high altitude, preventing hypoxia. Special aviation cannula systems are manufactured for this purpose

Storage and Delivery of Medical Gases

Scanlan-chapter 37

In the Beginning«

‡ ³Oxygen Service´ was the beginning of the present day skilled technology of Respiratory Care

‡ Ensuring a safe, uninterrupted supply of medical gases is still a key responsibility of therapists

Medical gas classification

‡ Laboratory Gases

± Used for equipment calibration and diagnostic testing

‡ Therapeutic Gases

± Used to relieve symptoms and improve patient¶s oxygenation

‡ Anesthetic Gases

± Combined with oxygen to provide anesthesia during surgery

Gases

‡ Symbols

‡ Physical characteristics

‡ Ability to support life

‡ Fire risk

± Flammable (burns readily, potentially explosive)

± Nonflammable (do not burn)

± Nonflammable, but support combustion (oxidizing)

Oxygen

‡ Colorless, odorless, transparent, tasteless

‡ Exists naturally as molecular oxygen

‡ Nonflammable, but accelerates combustion

‡ Production

± Fractional distillation (most large quantities)

± Physical separation

Air

‡ Colorless, odorless, naturally occurring

‡ Oxygen, nitrogen, trace gases

‡ Medical grade air produced by filtering and compressing atmospheric air Carbon Dioxide

‡ Colorless and odorless, does not support combustion or maintain animal life

‡ Produced by heating limestone in contact with rater

‡ Mixtures of oxygen and 5% to 10% carbon dioxide once used for therapeutics

± Treat hiccups and atelectasis

‡ Limited therapeutic use today

‡ Calibrate blood gas analyzers

Helium

‡ Second lightest gas of all

‡ Cannot support life, breathing 100% He would result in suffocation

‡ Helium must be mixed with at least 20% oxygen for therapeutics

‡ Heliox used to manage severe cases of large airway obstruction

Nitrous Oxide

‡ Can support combustion, but cannot support life if inhaled in a pure form

‡ Only dangerously high levels of nitrous provide true anesthesia, so generally a mix of nitrous oxide and oxygen are combined with other anesthetic agents

‡ Long term exposure associated with neuropathy and fetal disorders

Nitric Oxide

‡ FDA approved for use in the treatment of term and near-term infants for hypoxic respiratory failure

Storage of Medical Gases

‡ Medical gases are stored in portable high pressure cylinders or in large bulk reservoirs

Gas cylinders

‡ Made of seamless steel

‡ Classified by the federal DOT

± 3A from carbon steel

± 3AA from steel alloy tempered for higher strength

Markings and Identification

Safety Tests

‡ Conducted every 5 or 10 years

‡ Cylinders are pressurized to 5/3 of their service pressure

‡ An asterisk denotes approval for 10-year testing

‡ A plus sign means the cylinder is approved for filling to 10% above its service pressure (2200 psi)

Color Codes (US)

‡ Oxygen Green

‡ Carbon dioxide Gray

‡ Nitrous oxide Blue

‡ Helium Brown

‡ CO2/O2 Gray/Green ‡ He/O2 Brown/Green

‡ Air Yellow

Colors

‡ Colors should only be a guide

‡ Always identify though inspection of the label

‡ Analyze oxygen concentration prior to use

Cylinder Sizes

‡ ³Small´ E through AA²post valve and yoke connector

± Transport and anesthetic gases

‡ ³Large´ F through H²threaded valve outlet

Cylinder Sizes

Cylinder Safety Relief Valves

‡ An increase in gas temperature increases gas pressure

± If temperature increases too much, cylinder can explode

‡ Frangible disk (ruptures at specific pressure)

‡ Fusible plug (melts at a specific temperature)

± Small cylinders

‡ Spring-loaded valve (opens and vents gas at a set high pressure)

± Large cylinders ‡ Located in the cylinder valve stems

Valve outlets

Filling Cylinders

‡ Depends upon if the contents are gaseous or liquid

‡ Compressed Gas

± Filled to service pressure (or 10% above, if approved)

‡ Liquefied Gas

± Carbon dioxide and nitrous oxide can be stored as liquids at room temperature

Ȉ Filled to a specified filling density

Measuring Cylinder Contents

‡ Compressed Gas

± Volume of gas is proportional to its pressure at a constant temperature

‡ Liquid Gas

± Weighing is the only accurate method for determining contents

Cylinder Duration

‡ To estimate:

± Gas flow

± Cylinder size

± Cylinder pressure at the start of therapy ‡ For a given flow, the more gas a cylinder holds, the longer it will last

‡ The higher the flow, the shorter the emptying time

Cylinder Factors

‡ Gas volume conversion 28.3 L =1 cubic foot

‡ Derived for each common gas and cylinder size.

‡ Cu feet (full) x 28.3/pressure (full)

‡ O2 and air

± E (0.28) H (3.14)

Cylinder Duration (Gas)

‡ Duration of flow

± (Pressure x Cylinder factor)/Flow

‡ Must be sure the cylinder does not run dry during transport, have a safety cushio

Example

‡ Patient A is traveling to X-ray with an e cylinder. The tank has 2000 psi. The patient is on a 4 L nasal cannula. How long will the tank last?

Cylinder Duration (Liquid)

‡ Only accurate method for determining volume in a liquid cylinder is by weight

‡ 1L of liquid weighs 2.5 lbs and produces 860L of oxygen in its gaseous state

‡ Amount of gas = Liquid weight x 860

2.5 lb/L ‡ Duration ± Amount of gas (L)/Flow (L/min)

Example

‡ How long will Patient A¶s liquid container last if it contains 4 pounds of liquid oxygen and her nasal cannula is running at 3 L/min?

Cylinder Safety

‡ Guidelines by the National Fire Protection Agency and the Compressed Gas Association

± Cylinder Storage

± Cylinder Transport

± Cylinder use

Ȉ DzCrackdz the cylinder

Bulk Oxygen

‡ Large acute care facilities use huge amounts of oxygen daily

± Bulk storage and delivery systems are required

Ȉ Initially expensive, but less expensive than cylinders over the long term

Ȉ Less prone to interruption

Ȉ Eliminate the inconvenience and hazard of transporting and storing large numbers of cylinders

Ȉ Regulate delivery pressures centrally, eliminating the need for separate pressure reducing valves at each outlet

Gas Supply Systems

‡ Alternating supply system or cylinder manifold system

‡ Cylinder supply system with reserve supply

‡ Bulk gas system with a reserve Alternating Supply System

Alternating Supply System

Liquid Stand Tank

Bulk Oxygen Safety

‡ NFPA sets standards for the design, construction, placement and use of bulk systems

‡ Must have a reserve or backup supply to equal the average daily gas usage of the hospital

‡ Respiratory care personnel must have a protocol to identify and prioritize affected patients during a gas failure

‡ Back-up equipment

‡ Engineers responsible for fixing the problem

Distribution and Regulation of Medical Gases

‡ Before it can be administered to a patient, a medical gas must be delivered to the bedside and the pressure reduced to a workable level

‡ Modern hospitals use an elaborate piping network (vacuum sources may also be included)

‡ Transport still used cylinders

Central Piping Systems

‡ Gas pressure reduced to a standard woking pressure of 50 psi at the bulk location

‡ Main alarm warns of pressure drops or disruption of flow

‡ Zone valves ‡ Wall or station outlets

Central Piping Systems

Safety Indexed Connector System

‡ One risk in medical gas therapy is giving the wrong gas to a patient

± Carefully reading the cylinder or outlet labels is the best way to avoid accidents

± Safety systems have been developed to avoid misconnection between equipment and gases

Safety Indexed Connector System

‡ ASSS

± Threaded, large cylinders

‡ PISS

± Small cylinders, pin system

Ȉ Oxygen (2-5); Air (1-5)

‡ DISS

± Low pressure (<200 psi) gas connectors

Ȉ Outlets of pressure reducing valves

Ȉ Station outlets

Ȉ Inlets of blenders, flowmeters, ventilators

ASSS

PISS

DISS

Quick Connect Systems

Regulating Gas Pressure and Flow

‡ If the goal is solely a reduction in gas pressure, a reducing valve is used

‡ To control gas flow to a patient, a flowmeter is used

‡ If control of pressure and flow is needed, a regulator is used

Working Pressure

‡ In the US, 50 PSI is the working pressure

‡ For bulk systems, built in reducing valves decrease the pressure prior to the station outlet.

‡ Flow must still be controlled with a flowmeter, if oxygen therapy or nebulized medications are to be given

High Pressure Reducing Valves

‡ Single Stage

± Satisfactory for most routine hospital work

‡ Multiple stage

± The number of stages can be determined by noting the number of relief vents present

‡ Preset

‡ Adjustable ‡ Box 34-1

Preset reducing valve

Adjustable reducing valve

Low Pressure Gas Flowmeters

‡ Needed to set and control the rate of gas flow to a patient

± When the gas source is a high-pressure cylinder, a regulator (reducing valve plus flowmeter) is required

± For bulk systems, the pressure is reduced when it reaches the outlet station, so only a flowmeter is required

Flowmeters

‡ Flow restrictor

‡ Bourdon gauge

‡ Thorpe tube

Flow Restrictor

‡ Simplest and least expensive flow-metering device

‡ A fixed orifice calibrated to deliver a specific flow at a constant pressure (50 psi)

‡ Common for home oxygen delivery

‡ Box 34-2

Flow restrictor

Bourdon Gauge ‡ A flow-metering device that is always used in combination with an adjustable pressure reducing valve

± Operates under variable pressures, but is fixed orifice

‡ The gauge actually measures pressure changes, but displays the corresponding flow

‡ Gravity does not affect a Bourdon Gauge

± Good for transport

± Disadvantage is the inaccuracy when pressure distal to the orifice changes

Bourdon Gauge

‡ If high-resistance equipment is used, downstream pressure increases. The flow reading on the gauge depends on upstream pressure which stays constant. The gauge will read falsely higher than the actual flow.

‡ If the outlet is completely occluded, it will still register flow because upstream pressure is being measured

Bourdon Gauge

Bourdon Gauge

Bourdon Gauge

Thorpe Tube

‡ Always attached to a 50 psi source, either a preset reducing valve or a bedside outlet

‡ Variable orifice, constant pressure flow-metering device

‡ To read, one simply compares the float position to an adjacent calibrated scale, normally l/min Thorpe Tube

‡ Measures True flow

‡ Pressure compensated

± Prevents back pressure from affecting meter accuracy

± Manufacturers now supply only this type for medical gas administration

‡ Uncompensated

± Problems occur when certain types of equipment are connected (increase in downstream resistance)

Ȉ Thorpe tube will falsely read a flow lower than is actually delivered to the patient

Thorpe tube

‡ When compensated Thorpe tubes are connected to a 50 psi source with the needle valve closed, the float ³jumps´ then returns to zero

‡ The only factor limiting the use of a compensated Thorpe tube is gravity

± Only accurate in an upright position, not ideal for transport

Bronchial Hygiene Therapy Scanlan Chapter 37

Physiology of Airway Clearance ‡ Normal Clearance ‡ Requires a patent airway, a functional mucociliary escalator, and an effective cough.

‡ Cough reflex (a reserve mechanism)

± Irritation, inspiration, compression, expulsion ± Figure 37-1

Abnormal Clearance

‡ Any abnormality that alters airway patency, mucociliary function, or the effectiveness of the cough reflex can impair clearance and cause retained secretions. ‡ Full obstruction or mucus-plugging results in atelectasis and impaired oxygenation ‡ Partial obstruction can result in increased WOB and air trapping, overdistention due to restricted airflow. ‡ Role of infection

Abnormal Clearance ‡ Impaired cough reflex

± Table 37-1

‡ Artificial Airways

‡ Impaired mucociliary clearance

± Box 37-1

Diseases associated with abnormal clearance

‡ Internal obstruction (foreign bodies, kyphoscoliosis, tumors, mucus hypersecretion as with asthma)

‡ Alter mucociliary clearance (CF, bronchiectasis)

General Goals and indications

‡ Mobilize and remove retained secretions, with the ultimate aim to improve gas exchange and reduce the WOB.

‡ Acute conditions

‡ Chronic Conditions

‡ Prevention of retained secretions

‡ Box 37-2

Generally not helpful for the following acute conditions ‡ Acute exacerbation COPD

‡ Pneumonia without significant sputum production

‡ Uncomplicated asthma

Determining the need for BH

‡ Requires proper initial and ongoing patient assessment

‡ Key factors (Box 37-3)

‡ AARC GUIDELINES 892-893

Postural Drainage ‡ Involves the use of gravity and mechanical energy to help mobilize secretions.

± Turning ‡ Rotation of the body around the longitudinal axis

‡ By self or by a caregiver or via a special bed

‡ Benefits

‡ contraindications

Postural drainage

‡ Uses gravity to help move respiratory tract secretions from distal lung lobes into the central airways, where they can be removed by cough or suctioning

‡ Place the segment to be drained up

‡ Hold positions 3-15 minutes ‡ Most effective for conditions with excess sputum production

Technique

‡ Before or at least 1½ -2hours after meals or tube feeds

‡ Modify head down positions as needed

‡ Coordinate with pain meds as needed

‡ Use caution with IV¶s, vent tubing, and other equipment

‡ Restore patient as you found them

‡ Positions fig 37-3 Percussion and vibration

‡ Application of mechanical energy to the chest wall by using either the hands or various electrical or pneumatic devices. ‡ Designed to augment secretion clearance ‡ Percussion²jars the retained secretions loose, making removal easier ‡ Vibration²should aid movement of secretions to the central airways during exhalation. ‡ Manual ‡ Mechanical

Cough Techniques

‡ Most BH therapies only help move secretions into the central airway. Actual clearance must be accomplished by cough or suctioning.

‡ Cough is an essential component of ALL therapies

Directed cough

‡ Deliberate maneuver that is taught, supervised, and monitored

‡ Mimics an effective spontaneous cough, helps provide voluntary control over the reflex, and compensate for physical limitations that can impair this reflex ‡ Most effective in clearing secretions from the central, but not peripheral airways

Limitations

‡ Paralyzed or uncooperative patients. Some patients with advanced COPD or severe restrictive disorders may not be able to achieve an effective spontaneous cough.

‡ Pain may limit success. Patient teaching

‡ Instructing proper position

‡ Instructing breathing control

‡ Exercises to strengthen the expiratory muscles

Modifications

‡ Pre-op training if possible

‡ Splinting

‡ For some COPD patients, a moderate breath may be more effective

‡ Pursed lip exhalation

‡ ³huff, huff, huff´

manually assisted cough or ³chest compression´

‡ external application of pressure to the thoracic cage or epigastric region, coordinated with forced exhalation

‡ Contraindications

‡ Complications

± Table 37-2

Forced Expiration technique (FET) or huff cough

‡ A modification of the normal directed cough

‡ Consists of one or two forced expirations of middle to low lung volume without closure of the glottis, followed by a period of diaphragmatic breathing and relaxation

‡ Helps clear secretions with less change in pleural pressure and less likelihood of bronchiolar collapse

Uses

‡ Patients prone to airway collapse during normal coughing: emphysema, CF, bronchiectasis.

‡ Note

± Requires patients generate high expiratory airflow, may not be attainable in intubated patients with respiratory failure

Active cycle of breathing

‡ Renamed FET to emphasize the importance of breathing exercises

‡ Cycles

± Box 37-4 Breathing control

‡ Gentle diaphragmatic breathing at normal tidal volumes with relaxation of the upper chest and shoulders

‡ Intended to help prevent bronchospasm

Thoracic expansion

‡ Involves deep inhalation with relaxed exhalation

‡ Helps loosen secretions, improves distribution of ventilation, provides volume for FET FET

‡ Moves secretions into the central airways

‡ Most beneficial combined with postural drainage

‡ Not useful with young children (<2 years old) or the extremely ill

Autogenic Drainage

‡ Utilizes 3 distinct phases of varying lung volumes and expiratory airflow (Fig 37-7) ± Full inspiratory capacity maneuver, followed by breathing at low lung volumes ± Designed to unstuck peripheral mucus ± Breathing at low to middle lung volumes ± Collects mucus in the middle airways ± Increasing larger volumes ± Evacuation phase ‡ Coughing should be suppressed until all three phases are complete ‡ Difficult to teach patients

Mechanical insufflation-exsufflation

‡ Used with patients with neuromuscular disorders

‡ Delivers a positive-pressure breath of 30-50 cm H2O over 1-3 seconds via an oral nasal mask or airway.

‡ Pressure abruptly reversed to ±30 to ±50 cm H2O and maintained for 2 to 3 seconds.

Mechanical insufflation-exsufflation

‡ Typically consists of five cycles followed by a period of normal breathing (avoids hyperventilation)

‡ Repeat five or more times until secretions cleared

‡ Hazards

Positive Airway Pressure

‡ Help mobilize secretions and treat atelectasis

‡ Always combined with directed cough or other airway clearance technique

‡ CPAP

‡ EPAP

PEP

‡ Involves active expiration against a variable flow resistance

‡ Theory of moving secretions into the larger airways ± Fills underaerated or nonaerated segments via collateral ventilation ± Prevents airway collapse during expiration

‡ Useful for CF, COPD, prevent or reverse atelectasis

‡ Procedure (box 37-5)

High Frequency Compression/Oscillation

‡ Rapid vibratory movement of small volumes of air back and forth in the respiratory tract

Types

‡ Airway application

± Flutter valve

± Combines EPAP with high frequency oscillations at the airway opening

± Pipe shaped device with a heavy steel ball sitting in an angled ³bowl´

± Creates a positive pressure of 10-25 cm H2O and ball flutters at about 15 Hz.

± Still mixed results

Intrapulmonary percussive ventilation (IPV)

‡ Uses a pneumatic device to deliver a series of pressurized gas minibursts at rates of 100 to 255 cycles per minute to the respiratory tract, usually via a mouthpiece.

‡ Encompasses a pneumatic nebulizer for delivery of aerosol.

External (chest wall) application

‡ High frequency chest wall compression (HFCC) ± Two part system ± Variable air pulse generator ± Nonstretch inflatable vest that covers the patient¶s entire torso (ThAIRapy vest) ‡ Small gas volumes are alternately injected into and withdrawn from the vest by the air-pulse generator at a fast rate, creating an oscillatory motion against the patient¶s thorax. HFCC ‡ 30 minute sessions at frequencies between 5 and 25 Hz.

‡ Identify the frequency that produces the highest flows and largest volumes in a given patient

‡ Expensive

Hayak oscillator

‡ Uses a turtle shell strapped to the anterior chest wall

Mobilization and exercise

‡ Immobility is a major factor contributing to retention of secretion.

± Exercise improves overall aeration and ventilation-perfusion matching

Selecting bronchial hygiene techniques

‡ Box 37-6

‡ Use with specific conditions (table 37-3)

Egan¶s ± chapter 39

Lung Expansion Therapy

 Pulmonary complications are the most common serious problems seen in patients who have undergone thoracic or abdominal surgery

± Atelectasis, pneumondia, acute respiratory failure

 Lung expansion therapy is the most common form of respiratory care utilized in high- risk patients

Modalities to prevent or correct atelectasis

 IPPB

 IS

 CPAP

 PEP

 It is not always clear what the best method is because there are no clear advantages of one method over another.

Causes and Types of Atelectasis

 2 primary types in post-op and bedridden patients

± Resorption atelectasis

± Passive atelectasis

Resorption Atelectasis

 Occurs when mucus plugs are present in the airways and block ventilation to the affected region

 Gas distal to the obstruction is absorbed by the passing blood in the pulmonary capillaries, which causes the nonventilated alveoli to partially collapse

Passive Atelectasis

 Caused by persistent use of small tidal volumes by the patient

 Common when general anesthesia is given, with the use of sedatives and bed rest, and when deep breathing is painful (broken ribs and surgery to the upper abdominal region). Weakening of the diaphragm can also can contribute.

 Results when patients do not periodically take a deep breath and full expand the lungs

Indications for Lung Expansion

 Atelectasis can occur in any patient who cannot or does not take deep breaths periodically

± Neuromuscular disorder

± Heavily sedated patients

± Upper abdominal or thoracic surgery

± Lower abdominal surgery are at less risk, but still significant

± Spinal cord injuries

± Bedridden patients (trauma)

Post Operative patients  Shallow breathing

± Problem with an effective cough

 Leads to retained secretions

 History of lung diseases with increased mucus production

 Smokers

 Patients with inadequate nutritional intake (Albumin <3.2 mg/dL)

 The closer the incision is to the diaphragm, the greater the risk for post-op atelectasis

Clinical Signs of Atelectasis

 Medical history is a first clue

± Recent abdominal or thoracic surgery

± History of chronic lung disease or smoking

 Physical signs (may be absent or subtle, if minimal atelectasis)

± Respiratory rate increases

± Late-inspiratory crackles

± Diminished with excessive secretion blockage

± Tachycardia, if hypoxic

 Atelectasis alone does not produce fever, unless pneumonia is present

Signs

 Chest film often used to confirm atelectasis

 Area of increased opacity  Volume loss with patients with significant atelectasis

Lung Expansion Therapy

 All modes of lung expansion therapy increase lung volume by increasing the transpulmonary pressure gradient (difference between the alveolar pressure and the pleural pressure)

 The transpulmonary pressure gradient can be increased by:

± decreasing the pleural pressure

 Spontaneous deep breath

± Increasing the alveolar pressure

 Applying positive pressure to the lungs

Transpulmonary pressure gradient

Figure 39-1

Lung Expansion Therapy

 All lung expansion therapy uses one of these two approaches

 Decreasing the pleural pressure

± IS

 Increasing the alveolar pressure

± IPPB (inspiration)

± PEP (expiration)

± EPAP (expiration)

± CPAP (Both inspiration and expiration)

Lung Expansion Therapy

 All of these approaches are used, but those methods that decrease pleural pressure (IS) have more of a physiological effect than the others and are often most effective

± Require a patient that is alert, cooperative, and capable of taking a deep breath

Lung Expansion Therapy

 Goal of any lung expansion therapy should be to provide an effective strategy in the most efficient manner

± Staff time and equipment are two major issues related to efficiency

 For those at minimal risk of post-op atelectasis

± Deep breathing exercises, frequent repositioning and early ambulation are usually effective

 These can be completed with minimal clinician time and no equipment

Lung Expansion Therapy

 High risk patients usually use an IS

 Positive pressure therapy requires significantly more staff time and equipment and is reserved for the high risk patients who cannot perform IS

Incentive Spirometry

 Designed to mimic natural sighing by encouraging patients to take slow, deep breaths

 Performed using a device that provides visual cues to the patients when the desired flow or volume has been achieved

± Desired goal is set on the basis of predicted values or observation of an initial performance

Physiological Basis of IS

 A sustained, maximal inspiration (SMI) ± Slow, deep inhalation up to the total lung capacity, followed by a 5-10 second breath hold

± This is an inspiratory capacity (IC) followed by a breath hold

Indications for IS

 BOX 39-1

 Primary indication is to treat existing atelectasis, but may also be used as a preventive measure when conditions exist that make the development of atelectasis likely

Contraindication for IS

 Simple and Safe

 Box 39-2

 AARC Clinical Practice Guidelines p.907

Hazards and Complication of IS

 Hazards are few

 Acute Respiratory Alkalosis is most common

± Due to breathing too fast (hyperventilation)

 Dizzingess, numbness around mouth

 Slow patient breathing

 Discomfort is usually the result of inadequate pain control in the post-op patient

± Coordinate pain medication with IS

 Box 39-3

Equipment

 Typically simple, portable, and inexpensive  Volume oriented

± Measures actual volume

 Flow oriented

± Indicate inspiratory flow

 Flow x time = volume

Administering IS

 Planning

± Careful assessment

± Focus on outcomes (Box 39-4)

± Prefer to screen patient pre-op and orient to the device, if needed

 Implementation

± Success depends on effective patient teaching

± Set a goal that is attainable, but requires moderate effort

± Observe for proper technique

± Normal exhalation follow breath hold

± Rest between maneuvers

± Aim for at least 5-10 repetitions hourly

Administering IS

 Follow-up

± Return visits to ensure correct technique and goal achievement

± Once the patient has mastered, they can perform with minimal supervision

± Box 39-5

IPPB

 Application of inspiratory positive pressure to a spontaneously breathing patient as an intermittent or short-term therapy

 Treatments usually last 15-20 minutes

 Reverses the normal spontaneous pressure gradients, during inspiration alveolar pressure increases²exhalation passive

Indication for IPPB

 May be useful for patients with clinically diagnosed atelectasis not responsive to other therapies

 May be useful for patients at high risk for developing atelectasis and not able to cooperate with a simpler technique such as IS

 AARC Guidelines p.910

Concept

 In concept, a correctly administered IPPB treatment should provide the patient with augmented tidal volumes, achieved with minimal effort

 The optimal breathing pattern to reinflate collapsed lung units with IPPB consists of slow, deep breaths that are held at end inspiration

Contraindication for IPPB

 Box 39-6

 With the exception of untreated tension pneumothorax, most of these contraindicaitons are relative

Hazards and Complications

 Box 39-7

± Respiratory alkalosis can be avoided by proper coaching

 Gastric distension is the greatest risk in patients receiving IPPB at high pressures Administering IPPB

 Preliminary Planning

± Need for IPPB should be determined and desired therapeutic outcomes should be set (Box 39-8)

± Outcomes should be as explicit and measurable as possible

Evaluating Alternatives

 Before starting IPPB, the RRT and physician must determine whether simpler and less costly methods might be as effective in achieving the desired outcomes.

± If this is the case, simpler alternatives should be assessed first

Baseline Assessment

 Conduct baseline assessment prior to beginning therapy

 Medical History

 Should include evaluation of the patient¶s clinical status and a specific assessment related to the chosen therapeutic goals

± Measure vital signs

± Assess appearance and sensorium

± Breathing pattern and chest auscultation

Implementation

 Infection Control

 Equipment Preparation

± Be sure equipment is in working order

± Pressure cycled IPPB devices will not end inspiration if leaks in the system occur, check circuit prior to each use  Occlude the patient connector and manually trigger a breath, if it cycles offȄleak free

Implementation

 Patient Orientation

± Carefully explain purpose of therapy to patient

 Why the physician ordered the treatment

 What the treatment does

 How it will feel

 What are the expected results

± Be sure the patient adequately understands the procedure and the importance of cooperation

± May need to demonstrate with a test lung

Implementation

 Patient Positioning

± Semi-Fowlers position

± Supine is acceptable only if upright positioning is contraindicated

Implementation

 Initial Application

± May need nose clips until the technique is understood

± Mouthpiece must be inserted past the lips and a tight seal made

 Mask may be used for alert and cooperative patients who otherwise cannot create a seal

± Machine set so a breath can be initiated with minimal patient effort (1-2 cm H2O)

Implementation

 Initial Application (continued) ± Initial system pressure 10-15 cm H2O, adjust to achieve desired volume

± Low to moderate flow, and adjust to patient breathing pattern

± Breathing pattern of about 6 breaths/minute with an I:E ratio of 1:3 or 1:4

± These may need adjusted according to the patient needs

± Careful monitoring and coaching is a must

Implementation

 Adjusting Parameters

± Pressure and flow should be adjusted and monitored according to the goals of the therapy

± IPPB should be volume-oriented when used to treat atelectasis

± Determining volume goals

 Tidal volume of 10-15 mL/kg or at least 30% of the patients predicted IC

 Pressures can be gradually raised until the patient meets the goal

Implementation

 Adjusting parameters

± Patient should encourage the patient to breath actively during the positive pressure breath

± IPPB is only useful in the treatment of atelectasis if the volumes delivered exceed those volumes achieved by the patients spontaneous efforts

Discontinuation and Follow-up

 Posttreatment Assessment

± Repeat patient assessment

± Identify any side effects

± Evaluate need at least every 72 hours or with any change of patient status  Recordkeeping

± Pre and post assessment

± Unwanted patient response must be reported attending nurse and physician

Monitoring and Troubleshooting

 Machine Performance

± Large pressure swings early in inspiration indicate an incorrect sensitivity

± Pressure drops after inspiration begins or fails to rise until end inspiration, the flow is too low

± Cycles of prematurely (flow too high, airflow is obstructed by kinked tubing, or active resistance to inhalation by the patient)

± Pressure cycled IPPB will not reach it cycling pressure and cycle off (Leak² differentiate between patient and equipment as cause)

Monitoring and Troubleshooting

 Patient Response

± If a problem arises ³Triple S´

 Stop

 Stay

 Stabilize

Positive Airway Pressure (PAP)

 PAP uses positive pressure to increase the Transpulmonary Pressure gradient and enhance lung expansion

 Does not need complex machinery

Definitions and Physiological Principle

 PEP, EPAP, CPAP  All three have been shown to be equally effective in treating atelectasis in most post-op patients

 PEP and EPAP are most often used for Bronchial Hygiene (chapter 40)

 For hyperinflation, we will discuss the intermittent use of CPAP

Definitions and Physiological Principle

 CPAP maintains a positive airway pressure throughout inspiration and expiration

 CPAP elevates and maintains high alveolar and airway pressures throughout the full breathing cycle

 This increases the transpulmonary pressure gradient throughout inspiration and expiration

Definitions and Physiological Principle

 The patient typically breathes through a pressurized circuit against a resistor with pressures maintained between 5 and 20 cm H2O

 The following factors contribute to CPAP¶s benefits

± The recruitment of collapsed alveoli via increase in FRC

± Decreased work of breathing due to increased compliance or abolition of auto PEEP

± Improved distribution of ventilation through collateral channels

± An increase in the efficiency of secretion removal

Indications for CPAP

 Evidence supports use of CPAP therapy in treating post op atelectasis, but the duration of beneficial effects may be limited (benefits may be lost within 10 minutes)

 Suggest using CPAP on a continuous, not intermittent basis

Contraindications for CPAP  Hemodynamic instability

 Hypoventilating patients, may not have adequate ventilation

 Patients with nausea, facial trauma, untreated pneumothorax, and elevated ICP

Hazards and Complications of CPAP

 Increased work of breathing caused by the apparatus

 CPAP does not augment spontaneous ventilation, so patients may hypoventilate

 Barotrauma (especially in patients with emphysema and blebs)

 Gastric Distension if pressures above 15 cm H2O

± Vomiting and aspiration

Equipment

 Key elements

± Gas mixture from an oxygen blender

± Flows continuously through a humidifier

± Into the inspiratory limb

± Reservoir bag for reserve volume if the patients demand exceeds that of the system

± Simple t-piece connector

± Pressure alarm system with a manometer

± Expiratory limb

± Connected to a threshold resistor

 Due to the closed system, there must be an emergency inlet valve²in case of gas source failure

CPAP system

Administering Intermittent CPAP  Planning

± Determine desired outcomes

 An improvement in breath sounds

 Vital sign improvement

 Resolution of abnormal x-ray

 Restoration of normal oxygenation

 Procedures

± Appropriate CPAP level is determined on an individual basis

Administering Intermittent CPAP

 Monitoring and Troubleshooting

± A real danger of hypoventilation

± Patients must be adequately able to rid themselves of CO2 for therapy to be successful

± Monitor closely for unwanted effects

± CPAP device must be equipped with a means to monitor the pressure delivered and alarms to indicate the loss of pressure due to system disconnect or mechanical failure

Administering Intermittent CPAP

 Most common problem is system leaks

 When using a mask, a tight seal must be maintained

± This may cause pain and irritation in some patients

± New nasal CPAP units have addressed some of the comfort issues and helped with leaks

 Gastric insufflation and aspiration of stomach contents is a more serious problem  RTs must ensure adequate gas flow to meet the patient needs (2-3 times their minute volume)

± Flow is adequate if system pressure drops no more than 1-2 cm H2O during inspiration

Selecting an Approach

 Use the safest, simplest, most effective method for a given patient

 Need in-depth knowledge of methods and the individual patient needs

Protocol

Aerosol Drug Therapy

Scanlan ± chapter 36

Aerosols

 An aerosol is a suspension of solid or liquid particles in gas

 They can occur in nature as pollens, spores, dust, smoke, smog, fog, and mist

 The upper airway must filter these.

 In clinical settings, generated by atomizers, nebulizers, or inhalers

 Can deliver bland water or drugs

 Target lungs, throat, nose

Medical aerosol therapy

 The aim is to deliver a therapeutic dose of the selected agent to the desired site of action

 Indication for any specific aerosol is based on the need for the specific drug and the targeted site of delivery

 Aerosol drugs are delivered directly to the site, resulting in therapeutic action with minimal systemic side effects

Therapeutic Index

 A high index is the result of improved therapeutic action, with less systemic side effects Characteristics of Therapeutic Aerosols

 Aerosol output

 Particle size

 Deposition

Aerosol output

 Mass of fluid or drug contained in the aerosol produced by a nebulizer

 Emitted dose: describes the mass of drug leaving the mouthpiece of a nebulizer or inhaler as aerosol

 The mass leaving the nebulizer tells little about the amount of drug reaching the lung

 Variables include particle size and breathing patterns

Particle Size

 Particle size depends on the substance being nebulized, the nebulizer chosen, the method used to generate the aerosol and the environmental conditions surrounding the particle

 You cannot tell optimal particle size by visualization, you must perform lab measurement

Terminology

 Heterodisperse: containing particles of many sizes

 Mass median aerodynamic diameter (MMAD): an expression of average size of the aerosol particles

 Geometric standard deviation (GSD): describes the variability of particle sizes in an aerosol distribution

 Monodisperse: aerosol particles of similar size

Particle Size  Most aerosols found in nature and used in respiratory care are composed of particles of different sizes (heterodisperse)

 Only those used in lab research and nonmedical industry tend to be monodispersed

Deposition

 Aerosol particles are deposited when they leave suspension in gas

 Inhaled dose is the amount of drug inhaled

 Respirable mass is the proportion of the drug mass of proper size to reach the lower airway

 About 1-5% of the inhaled drug may be exhaled instead of deposited

 Key mechanisms of deposition:

 Inertial impaction, sedimentation, diffusion

Inertial impaction

 Occurs when suspended particles in motion collide with and are deposited on a surface

 The primary deposition mechanism for particles larger than 5 micrometers

 Turbulent flow patterns, obstructed pathways and inspiratory flow rates greater than 30 L/min are associated with increased inertial impact

 Particles in the 5-10 micrometer range tend to deposit in the oro- and hypopharynx

Sedimentation

 Occurs when aerosol particles settle out of suspension and are deposited due to gravity

 During normal breathing, this is the primary mechanism for deposition in the 1-5 micrometer range

 Occurs most often in the central airways and increases with time

 Breath holding enhances sedimentation

 A 10 second breath hold can increase aerosol deposition as much as 10%.

Diffusion  Brownian diffusion is the primary mechanism for deposition of small particles (<3 micrometers) mainly in the respiratory region where bulk as flow ceases and most aerosol particles reach the alveoli by diffusion

 Particles between 1 and .5 micrometers are so stable that most remain in suspension and are exhaled, particles less than .5 micrometers have a greater retention in the lungs

Rule of Thumb

 Deposition varies with particle size

 Target the desired location by using the appropriate particle size.

Aging

 The process by which an aerosol suspension changes over time

 Particles constantly grow, shrink, coalesce, and fall out of suspension

 They can change size due to evaporation or hygroscopic water absorption

 The rate of particle size change is inversely proportional to the size of a particle

 Small particles change faster than large particles

Determining deposition

 Inspiratory flow rate

 Flow pattern

 Respiratory rate

 Inhaled volume

 I:E ratio

 Breath holding

Deposition  The presence of airway obstruction is one of the greatest factors influencing aerosol deposition.

 Pulmonary deposition is greater in smokers and patients with obstructive airway disease than in healthy persons

 Figure 36-4

Aerosol delivery Quantification

 At the bedside, quantification is based on the patient¶s clinical response to the drug with either the desired effects or the unwanted adverse effects

Hazards of aerosol therapy

 Primary hazard is an adverse reaction to the medication being delivered

 Infection

 Commonly due to contaminated solutions, caregivers hands, or the patients own secretions

 Primarily gram negative bacilli (pseudomonas aeruginosa and legionella pneumophila)

 Sterilize nebulizers between patient

 Frequently replace units

 Rinse with sterile water every 24 hours and air dry

Hazards of aerosol therapy

 Airway Reactivity

 Can cause bronchospasm in some patients when exposed to cold or high-density aerosols, and some medications

 Pretreat with bronchodilator

 Pulmonary and Systemic Effects

 Associated with the site of delivery and the drug being administered  Preliminary assessment should balance the need of therapy against the risks

 Suction may be indicated in patients unable to clear their own secretions

Hazards of aerosol therapy

 Drug Concentration

 During the evaporation, heating, baffling, and recycling of drug solution undergoing jet or ultrasonic nebulization, concentrations of the solution may increase

 Can expose patient to increasingly higher concentrations of the drug over the course of therapy

Ȃ Large amount of drug may remain in the nebulizer at the end of therapy

 Occurs more often when nebulized for an extended time period, for example CNBT

Aerosol Drug Delivery Systems

 Effective aerosol therapy requires a device that quickly delivers sufficient drug to the desired site of action with minimal waste and at a low cost

 MDI

 DPI

 Jet nebulizers (small and large)

 USN

 Atomizers (including nasal spray pump)

MDI (pressurized MDI pMDI)

 Most commonly prescribed method of aerosol delivery in the US

 Portable, compact, and relatively easy to use

 Used correctly it is as effective as other nebulizers

 Can be used for spontaneously breathing or vent patients

 Uniform dose is dispensed

 Used for bronchodilators, anticholinergics and steroid delivery Equipment

Equipment

 A pressurized canister containing a drug

 Drug is a micronized powder dissolved or suspended in CFC or HFA propellant

 Aerosol production takes approximately 20 milliseconds

 CFC is being replaced by HFA as a propellant

 Dispersal agents such as soya lecithin and sorbitan trioleate help keep the drug suspended in the propellant and lubricate the valve stem

MDI

 Initial dose from a new canister contains less active dose than subsequent activations

 Before initial use, prime the MDI to the atmosphere 1 to 4 times (follow label)

 Serious limitation is the lack of a ³counter´ to indicate the number of doses

 ³Tail off´ may occur after the number of labeled doses are given in which 20-60 apparent doses are give with little or no medication

MDI

 Decreased temperature (less than 10 degrees Celsius) may result in decreased output of CFC MDI¶s

 Less of a problem with the HFA MDI

Aerosol Delivery Characteristics

 MDI¶s produce particles in the range of 3-6 micrometers, but about 80% of the dose deposits in the oropharynx  Pulmonary deposition ranges from 10-20%

Technique

 As many as 2/3 of patients and health professions who teach MDI use do not perform the procedure properly

 Thorough education including demonstration, practice, and confirmation of knowledge

 Demonstration with placebos

Technique

 ³Cold freon effect´

 Patient stops inhaling when the cold aerosol reaches the back of the mouth

 Care with use of anticholinergic agents and an open mouth technique because they are associated with increased ocular pressure and could be dangerous with glaucoma patients

 Box 36-1

Technique

 The high percentage of oropharyngeal deposition with use of steroid MDI¶s can increase the incidence of thrush and dysphonia

 Steroid MDI¶s should not be used alone, always with a spacer or holding chamber

 Rinse mouth

MDI Accessory Devices

 Two primary limitations of MDI

 Hand-breath coordination

 High oropharyngeal deposition

Accessory Devices

 Breath Actuated MDI

 Activated during inhalation, reduces need for coordination for patient  Autohaler²opens when patient¶s flow exceeds 30L/min

 Spacers and Holding Chambers

 Reduce the need for coordination and incidence of oropharyngeal deposition

 A spacer is a simple valveless extension device that adds distance between the MDI and the mouth.

 A Holding Champer has a one-way valve that hold the aerosol particles in until the patient inhales

 Box 36-2

Holding Chamber/Spacer

 Masks are available to use for adults, children, and infants

DPI

 Breath actuated metered dosing system

 Patient creates the aerosol by drawing air through a dose of finely milled drug powder

 Do not need propellants

 Do not require hand breath coordination

 Do need to create a turbulent flow in the inhaler

 As effective as MDI¶s

Equipment Design

Equipment Design

 Most DPI systems require the use of a carrier substance (lactose or glucose) mixed into the drug to enable the drug powder to flow out of the device

 Spinhaler/Rotahaler dispensed doses of drug from punctured gelatin capsules

 Turbuhaler is a multidose reservoir powder system preloaded to dispense 200 doses  Diskhaler uses four to eight individual blishter packs

 Diskus incorporates a tape system with up to 60 sealed single doses

Equipment Design

 Particle size of dry powder ranges from 1-3 micrometers, but the carrier agent ranges from 20-65 micrometers so the carrier is deposited in the oropharynx

 Optimal performance for each design occurs at a specific inspiratory flow rate

Equipment Design

 Ambient humidity affects drug delivery from DPI¶s

 Dose decreased in a humid environment, likely due to powder clumping

 DPI¶s are generally convenient and easy to use

 DPI¶s rely on a patient¶s inspiratory effort

Technique

 Most critical factor is the need for a HIGH inspiratory flow (>60 L/min)

 Infants and children less than 5 years and those unable to follow direction cannot develop a flow this high and cannot use DPI

 BOX 36-3

Jet Nebulizers

 Small Volume Nebulizers have small (less or equal to 10 mL medication reservoirs

 Powered by high pressure air or oxygen (compressors, cylinders or wall outlet)

 Factors affecting SVN perfomance: nebulizer design, gas pressure and density, medication characteristics

 Box 36-4

Terminology  Baffle: a surface on which large particles impact and fall out of suspension, a process that decreases the MMAD and GSD of the aerosol

 Sphere or plate, internal walls of the neb, etc

 Atomizers operate similar to the SVN but without baffling and produce aerosols with larger MMAD

Terminology

 Residual or dead volume is the medication that remains in the SVN after the device runs dry

 May be 0.5ml -2.2 ml of a 3 ml dose

 An effective nebulizer should deliver more than 50% of its total dose in the respirable range in 10 minutes or less

 The higher the flow of gas the smaller the particle size and the shorter the time to nebulizer

 Position of nebulizer will affect nebulization²some stop producing aerosol at a 30 degree tilt

Gas source

 Hospital versus home

 Gas pressure and flow affect particle size, distribution and output

 Nebulizers for home use should be matched to the compressor in order to increase efficiency

 Density

 Gas density affects both aerosol generation and delivery to the lungs

 Lower the density of a gas, the less turbulent the flow (heliox)

Ȃ Less impaction occurs and better deposition results

Humidity and Temperature

 They affect particle size and the concentration of drug remaining in the nebulizer

 Particles entrained in warm and fully saturated gas stream increase inside

Nebulization

 Continuous nebulization wastes medication because the aerosol is produced throughout the respiratory cycle and is lost in the atmosphere

 Breath enhanced nebulizers

 Use a series of one way valves to minimize waste

 Breath-actuated nebulizers

 Synchronize to breathing pattern, generate aerosol only during inspiration

Children and Infants

 They have smaller airway diameters than adults, breathing rate is faster, nose filters out large particles, and mouthpieces often cannot be used

 Mask

 ³Blow by´²not established to be effective by research

 Normal breathing is most effective,

 Never to a crying child, because it greatly reduces lower airway deposition²long expiratory phase, quick inspiration

Characteristics of Drug Formulation

 The viscosity and density affects output and particle size

 Some drugs such as antibiotics are so viscous they cannot be effectively nebulized in some standard SVN¶s

 SVN¶s can exhibit variable performance

 Evaluate before purchase

Technique

 SVN use is less technique and device dependent than MDI or DPI systems

 Slow inspiratory flow does improve SVN aerosol deposition  The nose is a filter of particles, so many clinicians prefer not to use a mask²However, as long as the patient breathes through the mouth there is little difference between mask and mouthpiece.

 Box 36-5

Infection Control Issues

 CDC recommends nebulizers be cleaned and disinfected or rinsed with sterile water and air dried between uses

 Multi-dose medication solutions should be store in a refrigerator

 Discard syringes used to draw up medication every 24 hours

Large Volume Jet Nebulizers

 Used to deliver aerosolized drugs to the lung

 A large volume nebulizer is particularly useful when traditional dosing strategies are ineffective in the management of severe bronchospasm

 If a patient does not respond to standard dosages it is common to repeat the treatment every 15 minutes

 Continuous nebulization therapy is an option

CNBT

 Heart and Hope nebulizers are devices used

 Have greater than a 200 ml reservoir producing aerosols between 2.2 and 3.5 micrometers

 Monitor patients closely for signs of drug toxicity on CNBT

SPAG

 Small particle aerosol generator (Fig.36-25)

 A special purpose large volume nebulizer specifically for administration of ribavirin to RSV patients

 Regulator is connected to two flow meters that control flow to a nebulizer and a drying chamber  Nebulizer Flow should be approximately 7 L/min with total flow of no lower than 15 L/min

Problems with SPAG

 Caregiver exposure to drug aerosol

 Delivery through a mechanical ventilation circuit

 Can occlude the circuit or jam breathing valves

SPAG

USN

 Uses a piezoelectric crystal to produce an aerosol

 Capable of higher outputs and higher densities than conventional jet nebulizers

 Large Volume USN: used for bland aerosol and sputum induction

 Small Volume: have been marketed for drug delivery

 Most designs have less dead space than SVNs and this reduces the need for large quantities of diluent to ensure drug delivery

USN

 Minimal residual drug volume

 Treatment time is reduced

Hand bulb Atomizer

 Hand bulb atomizer or nasal spray pump is used to deliver sympathomimetic, antimuscarinic, antiinflammatory, and anesthetic aerosols to the upper airway (nose, pharynx, and larynx)

 No baffles which make a high MMAD, ideal for upper airway deposition

Vibrating Mesh Nebulizers

 Active: uses a piezo ceramic element to generate droplems

 Passive: utilizes a mesh separated from an ultrasonic horn by the liquid to be nebulized New Generation Nebulizers

 Use of soft mist aerosol, improved particle characteristics, and systems that minimize residual volume improve these devices efficiency

 Some increase deposition from 10 to almost 60%

New Generation

 AERx: uses unit dose blister packs of fluid, built in inspiratory flow rate monitoring

 Respimat: mechanical energy creates an aerosol from liquid solutions. Requires hand- breath coordination

Advantages and Disadvantages

 Table 36-2

Selecting a Delivery System

 Considerations:

 Available drug formulation

 Desired site of deposition

 Patient characteristics

 See rule of thumb

 Patient preference

 AARC Guidelines page 827

 Figure 36-28

Assessment based bronchodilator therapy

 Ultimately it is the patient response that determines the therapeutic outcome

 Protocol relies heavily on bedside assessment of the airway obstruction

 Figure 36-30 Assessing patient response

 AARC Guideline p.831

Use and Limitations of PEFR

 PEFR is effort and volume dependent, evaluation of patient performance is somewhat subjective

 PEFR can be used at the bedside, conventional PFT remains the standard for determining bronchodilator response

Other components of Patient Assessment

 Sole dependence on expiratory airflow to assess therapy response is unwise

 Interview patient to determine history and current levels of dyspnea

 Observe for signs of increased WOB

 A decrease in wheezing accompanied by decrease in breath sound intensity is a worsening condition, but a decrease in wheezing with an increase in intensity is improvement

 Oxygen status with pulse oximetry

Dose Response Assessment

 Poor response is often due to an inadequate amount of drug reaching the airway.

 To determine the ³best´ dose for patients , the dose-response titration

 Simple albuterol dose response titration involves giving an initial 4 puffs at 1 minute intervals via MDI with holding chamber

 If no relief after 5 minutes, 1 puff per minutes until relieved or HR increases more than 20 bpm, tremors occur, or 12 puffs delivered

 Best dose: maximum relief with highest PEFR without side effects

Frequency of Assessment

 Box 36-7 Patient Education

 The patient¶s ability to understand the therapy and its goals significantly affects the therapeutic efficacy of any treatment

 Must teach basic administration tecnique

Continuous Nebulization for Refractory Bronchospasm

 Patients suffering severe exacerbation of asthma or acute bronchospasm that have taken standard dose of their bronchodilator without response

 Figure 36-31

 Mini Clini

Aerosol Administration to Intubated Patients

 Table 36-4

 Box 36-8

 Box 36-9

 SVN tends to deposit in tubing and expiratory filter

 MDI

Controlling Environmental Contamination

 Nebulized drugs that escape from the nebulizer into the atmosphere or are exhaled by the patient can be inhaled by anyone in the vicinity of the treatment

 Greatest occupational risk for the RCP

 Ribavirin and pentamidine

 Conjunctivitis, headaches, bronchospasm, SOB, and rashes

Controlling Environmental Contamination

 Negative Pressure Rooms  HEPA filters

 Booths and Stations

 PPE Humidity And Bland Aerosol Therapy Scanlan ± Chapter 35 Humidity Therapy

Humidity therapy involves adding water vapor and (sometimes) heat to the inspired gas Physiological Control of Heat & Moisture Exchange

Heat and moisture exchange is a primary function of the upper respiratory tract, mainly the nose.

± Heats and humidifies gas on inspiration

± Cools and reclaims water on exhalation

± The nasal mucosa is very vascular and actively regulates temperature changes in the nose

Mouth

The mouth is a less efficient heat and moisture exchanger Physiological Control

As inspired gas moves nto the lungs, it achieves BTPS (T-37C;c barometric pressure;saturated with water vapor)

Isothermic saturation boundary²normally approximately 5 cm below the carina

± A number of factors can shift the ISB deeper into the lungs

ISB Shift

Distally when a person breathes through the mouth

When breathing cold, dry air

Upper airway is bypassed (artificial tracheal airway)

Minute ventilation is higher than normal Indications for Humidification and Warming of Gas

Primary goal of humidification is to maintain normal physiological conditions in the lower airways

± Proper levels of heat and humidity ensure normal function of the mucociliary transport system

± Box 35-1

± As the airways are exposed to cold, dry air; ciliary motility is reduced, mucus production increases and becomes thick

Dry gases are even more hazardous if the upper airway is bypassed (maintain at least 60% of BTPS)

Recommended Heat and humidity levels

The amount of heat and humidity that a patient needs depends on the site of delivery

Table 35-1 Equipment

Humidifier: a device that adds molecular water to gas

Three variables affect the humidifier¶s performance

± Temperature

± Surface area

± Contact time

Temperature

The greater the temperature, the more water vapor it can hold

Easy way to improve effectiveness is to add a heater

Surface Area

The greater the area of contact between water and gas, the opportunity for evaporation to occur ± Passovers pass gas over a large surface area of water

More space-efficient ways to increase surface area:

Ȃ Bubble (directs a stream of gas underwater and the bubbles rise to the surface)

Ȃ Wick (uses porous water-absorbent materials to increase surface areaȄcapillary action)

Contact Time

The longer a gas remains in contact with water, the greater the opportunity for evaporation to occur.

± Bubble: depends on the depth of the water column²deeper column;more contact time

± Passover & Wick: flow rate of gas through the humidifier is inversely related too the contact time (low flows; more contact time)

Types of Humidifiers

Bubble

Passover

HME

These are either Active (actively adding heat and or water to the device/patient interface) or Passive (recycling exhaled heat and humidity from the patient)

ASTM establishes specifications for these Bubble

Breaks (diffuses) an underwater gas stream into small bubbles)

Commonly used with oronasal oxygen delivery systems

Goal is to raise the water vapor content of the gas

Unheated they can provide absolute humidity of approximately 15-20 mg/L Bubble As gas flow increases, these devices become less efficient as the reservoir cools and contact time is reduced

± Limited effectiveness at flows higher than 10L/min

Pressure-relief valve or ³pop-off´ at pressures above 2 psi

± Provide audible alarm

Can also use to test for leaks: If the system is obstructed by the RCP and the pop off sounds, it is leak free; failure to sound signifies a leak

Bubble

At high flow rates, bubble humidifiers can produce aerosols.

± May not be visible to the naked eye, but they can transmit pathogens from the reservoir to the patient

Bubble Humidifier

Passover

A passover directs gas over a water surface

Common types

± Wick

± Membrane

± Simple Reservoir Type

Wick Humidifier

The wick (a cylinder of absorbent material) is placed upright in a water reservoir and surrounded by a heating element

Capillary action continually draws water up from the reservoir and keeps the wick saturated As dry gas enters the chamber it flows around the wick, picks up moisture and leaves the chamber fully saturated with water vapor

No bubbling occurs Wick Membrane-type humidifier

Separates the water from the gas stream by means of a hydrophobic membrane

Water vapor molecules can easily pass through this membrane, but liquid water cannot Membrane-type Simple reservoir

Directs gas over the surface of a volume of water

Surface for gas-fluid interface is limited

May be used with mechanical ventilation (heated)

Non-invasive ventilation (unheated) Passover Advantages

Advantages over a bubble humidifier:

± They can maintain saturation at high flow rates

± They add little or no flow resistance to spontaneous breathing circuits

± They do not generate any aerosols, and thus pose a minimal risk for spreading infection

Heat & Moisture Exchangers

Most often a passive humidifier that has been described as an ³artificial nose´

An HME captures exhaled heat and moisture and uses it to heat and humidify the next inspiration

Traditionally, used to provide humidification to patients receiving invasive ventilatory support via trachs or endotracheal tubes Three types of HME

Simple condenser humidifier

Hygroscopic condenser humidifier

Hydrophobic condenser humidifier Simple condenser

Contains a condenser element with high thermal conductivity, usually a metallic gauze or corrugated metal

About 50% of the patients exhaled moisture is captured (50% efficiency) Hygroscopic condenser

Provides a higher efficiency by using a condensing element of low thermal conductivity (paper, wool, foam) and impregnating this with a hygroscopic salt (calcium or lithium chloride)

The low thermal conductive elements retain more heat and the salt helps capture extra moisture

70% efficiency Hydrophobic condenser

Use a water repellent element with a large surface area and low thermal conductivity

70% efficiency

Some also provide bacterial filtration HME

Design and performance standards are set by the International Organization for Standardization (ISO)

Ideal HME should:

± Operate at 70% efficiency or better (providing at least 30 mg/L) water vapor

± Use standard conections ± Add minimal weight, dead space, and flow resistance to a breathing circuit

HME HME

Moisture output of HME¶s tends to fall at high volumes and rates of breathing

High inspiratory flows and high FiO2 levels can decrease HME efficiency

HME flow resistance increases with water absorption (some patients may not tolerate this) HME

They eliminate the problem of circuit condensation

Some also help with nosocomial infection by reducing bacterial colonization in the vent circuit (especially hydrophobic filters)

Heating Systems

Heat improves the water output of bubble and passover humidifiers

Heated humidifiers are used mainly for patients with a bypassed upper airway and/or for those receiving mechanical ventilatory support 5 Types of Heaters

³Hot plate´ element at the base of the humidifier

A ³wraparound´ type that surrounds the humidifier chamber

A yolk, or collar, element that sits between the water reservoir and the gas outlet 5 Types of Heaters 4. An immersion-type heater with the element actually placed in the water reservoir

5. A heated wire in the inspiratory limb warming a saturated wick or hollow fiber

Heating Systems

The systems also have a controller that regulates the element¶s electric power Heating Systems

± In a simple system, the controller monitors the heating element, varying the current to match either a preset or adjustable temperature

The patientǯs airway temperature has no effect on the controller

Heating Systems

Servo-controlled heating system

± Monitors temperature at or near the patient¶s airway using a thermistor probe

± Adjust heater power to achieve the desired airway temperature

Thermistor probes should be placed in the inspiratory limb of the vent circuit far enough form the wye to ensure the warm exhaled gas does not fool the controller (Never place in an isolette or radiant warmer)

Both types have alarms and alarm-activated heater shut-down

Box 35-2

Reservoir and Feed Systems

Heated humidifiers operating continuously in breathing circuits can evaporate more than 1 L of water per day

± To avoid constant refilling, they employ a large water reservoir or use a gravity feed system

These should be safe, dependable and easy to set up and use, allow for continuity of therapy, enen when the reservoir is being replenished

Simple large reservoir

Manually refilled (with sterile or distilled water)

± This requires a momentary interruption of humidifier operation ± Because the system must be ³opened´ for refilling, cross contamination can occur

± A small inlet that can be attached to a gravity-fed IV bag and line allows refilling without interruption of service

Automatic Feed system

Avoid the need for constant checking and manual refilling of humidifiers

± Simplest type is the level-compensated reservoir

± Flotation valve controls are used to maintain humidifier reservoir fluid volume

As the water level drops, the float opens a feed valve to allow it to refill.

Automatic Feed System

Membrane humidifiers do not require float control, they use an open gravity feed system.

± These devices cannot overfill due to the underlying membrane.

The Hydrate

Uses Capillary force vaporization.

± This vaporizer is a thin film, high surface area boiler that combines capillary force and phase transition to apply pressure onto an expanding gas (water vapor) and ejects it.

Page 785

Clinical Practice

Humidification during Mechanical Ventilation

± AARC Clinical Practice Guideline (p. 786)

Setting Humidification Levels

American National Standards Institute recommends minimum levels of humidity for intubated patients of more than 30 mg/L

Target the temperature and level of humidity for the normal conditions for the point at which gas enters the airway

± Air entering the carina is typically 35-40 mg/L

± Set humidifiers to maintain airway temperatures in the range between 35-37C.

If too cold, airway plugging can occur.

AARC Guidelines

Recommends 33C, within 2C, with a minimum of 30mg/L of water vapor for mechanically ventilated patients with artificial airways

± Lower than this will cause mucosal dysfuction.

± Optimal level is 37C and 44 mg/L with 100% relative humidity.

Common Problems

Condensation

Cross Contamination

Proper Conditioning of the Inspired Gas Condensation

The gas cools as it leaves the point of humidification and passes through the delivery tubing to the patient.

As the gas cools, water vapor capacity decreases, resulting in ³rain out´

Influencing Factors

Temperature difference across the system

Ambient temperature

Gas flow

Set airway temperature Length, diameter, and thermal mass of the breathing circuit Risks

Condensation poses risks to patients and caregivers, and can waste a lot of water

Disrupts gas flow through the circuit

Alter FiO2

Can be aspirated

Infection risk Minimizing Problems

Treat condensate as infectious waste

± Wear gloves and goggles

Water traps at low points in the circuit, both limbs

± Drain away from patient¶s airway

Maintain a temperature in the circuit (reduce circuit cooling)

± Insulation of the circuit or wire heating elements in the circuit

Cross Contamination

Condensate is a known source of bacterial colonization

± Wick and membrane passovers prevent formation of bacteria-carrying aerosols

± High reservoir temperatures in humidifiers are bacteriocidal

± Used to believe changing vent circuits every 24 hours reduced risk, but now it is known that it actually increased risk

Weekly or may not need to change at all.

Proper conditioning of the Gas

Most regularly monitor FIO2 levels, but few monitor the condition of the inspired gas ± Hygrometer-thermometer systems accomplish this

± Adjust the temperature to the point that a few drops of condensation form near the patient wye

± Estimate that an HME is performing well at the bedside by visually confirming condensation in the flex tube

Bland Aerosol Therapy

A bland aerosol consists of liquid particles suspended in a gas

± Delivery of sterile water or hypotonic, isotonic, or hypertonic saline aerosols

Can be accompanied by oxygen therapy

Bland Aerosol

Clinical Practice Guidelines (p. 791) Equipment

Large volume jet nebulizers

Ultrasonic nebulizers

Delivery systems include direct airway appliances and enclosures Large Volume Jet Nebulizer

Most common device for bland aerosol

Pneumatically powered

Aerosol is generated by passing gas at a high velocity through a small ³jet´ orifice

± Resulting low pressure at the jet draws fluid from the reservoir up to the top of the tube, where it is shattered into liquid particles

Large-Volume Neb

Large particles fall out and the small particles are carried in the gas stream

± Baffling (Large particles impacting internal surfaces of the device) Variable air-entrainment ports allow FIO2 to be altered

If heat is required, wrap around, hotplate, or immersion heaters are available Large-Volume Neb

Larger versions of these with 2-3L reservoirs can deliver bland aerosols into mist tents

± Always run unheated due to heat build-up in an enclosure

Large Volume Neb USN

Electrically powered device that uses a piezoelectric crystal to generate aerosol

± This converts radio waves into high-frequency mechanical vibrations (sound)

± The vibrations are transmitted to a liquid surface where the intense mechanical energy creates a ³geyser´ of aerosol droplets

USN

USN

Signal frequency²determines particle size

± Usually preset

Signal amplitude²alters the transducer¶s vibrational energy and thus directly affects the amount of aerosol produced

± Adjusted by clinician

USN

Have unique capabilities, but in most cases their advantages over jet nebulizers are outweighed by their high cost and erratic reliability

Use for sputum induction is an exception ± 3% Saline

Airway Appliances

Aerosol face mask

Face tent

T-tube

Tracheostomy mask

Enclosures (Mist tents and Hoods)

± Problems are CO2 build up and heat retention

Sputum Induction

Useful, cost-effective, safe method for diagnosing TB, pneumocystis carinii, and slung cancer

Involves short term application of hypertonic saline (3%) to assist in mobilizing pulmonary secretions for evacuation and recovery

To ensure a good sample, must attempt to get true respiratory secretions, not saliva

Box 35-3 Problems

Cross contamination and infection

Environmental safety

Inadequate mist production

Bronchospasm

Noise

Troubleshooting

Adhere to infection control guidelines Poor mist production can be caused by inadequate input flow, siphon tube obstruction, or jet orifice misalignment

Overhydration is a problem with continuous use (USN¶s should never be used continuously due to high water outputs)

± Infants, small children, and those with fluid or electrolyte imbalances are at highest risk

Troubleshooting

Inspissated pulmonary secretions also can swell after high-density aerosol therapy, worsening airway obstruction

Bland aerosols can cause bronchospasm in some patients

± May need to pretreat with a bronchodilator

Noise generated by the large volume jet nebulizers is a problem, care with infants in incubators and oxygen hoods

± Best to use a passover humidifer in these cases

Selecting the appropriate therapy

Key consideration

± Gas flow

± Presence or absence of an artificial tracheal airway

± Character of the pulmonary secretions

± Need for and expected duration of mechanical ventilation

± Contraindications to use an HME

Selecting the appropriate therapy

Advises against using a bubble humidifier at flow rates of 4L/min or less

± May add to the patient who complains of nasal dryness or irritation when on a low flow oxygen device

Selecting the appropriate therapy

© WVNCC Last Updated:

Airway Management Scanlan ± Chapter 30 Airways ‡ Many patients have diseased lungs and impaired gas exchange. ‡ Adequate gas exchange is not always possible without an airway. Three Area of Skills ‡ Airway Clearance ‡ Insert and maintain artificial airways ‡ Assist physicians with special procedures Airway Obstruction ‡ Caused by retained secretions, foreign bodies, and structural changes (edema, tumors,or trauma)  Increased resistance and WOB, hypoxemia, hypercapnia, atelectasis, and infection Secretion Clearance ‡ Thickness or amount ‡ Patient¶s inability to generate an effective cough Suctioning ‡ Uses negative pressure (vacuum) to the airways through a collecting tube ‡ Upper airway (oropharynx)  Yankauer suction ‡ Lower airway (trachea and bronchi)  Flexible suction catheter  NT or ET

Endotracheal Suctioning ‡ Indication is to remove accumulated pulmonary secretions (page 656) ‡ No absolute contraindication ‡ Hazards  Hypoxia, tracheal trauma, cardiac arrhythmias, atelectasis, infection, etc. ‡ Assessment of need routinely with patient/vent checks Equipment and Procedure ‡ Assess for indications ‡ Assemble and Check Equipment (Box 30-1)  Pressures for vacuum ‡ Preoxygenate and Hyperinflate ‡ Insert catheter ‡ Apply suction ‡ Reoxygenate and hyperinflate ‡ Monitor patient and assess outcomes Catheter size ‡ OET internal diameter X 2, then use next smallest size catheter ‡ Only even numbers Closed suction system ‡ Box 30-2

Minimizing complications ‡ Preoxygenation  Prevent hypoxia and atelectasis  Cardiac arrhythmias ‡ Limit negative pressure and length of suctioning  Atelectasis, Mucosal trauma ‡ Sterile technique  infection

Nasotracheal Suctioning ‡ Indicated for patients who retain secretions, but do not have an artificial tracheal airway ‡ Guidelines page 660 Equipment and Procedure ‡ Similar to ET suction, highlight the differences:  Water-soluble lubricating jelly  NPA will help reduce mucosal trauma  Gentle insertion through nostril, twist catheter if you feel resistance.  Use sniffing position, advance until patient coughs Complications ‡ Gagging or regurgitation ‡ Airway trauma  Lubricate, technique ‡ Infection  Sterile technique

NT Suctioning Sputum Sampling ‡ Collected to identify organisms infecting the airway ‡ Maintain sterile technique ‡ Closed container ‡ Label and process Establishing Artificial Airways ‡ Required when the patient¶s natural airway can no longer perform its proper functions ‡ Page 662 Routes ‡ Pharyngeal ‡ Tracheal Pharyngeal ‡ Prevent airway obstruction by keeping the tongue pulled forward and away from the posterior pharynx  Common in the unconscious patient, due to a loss of muscle tone ‡ Nasal pharyngeal (NPA)  Frequent NT suctioning ‡ Oral pharyngeal  Inserted into mouth and over tongue  Only in unconscious patient to avoid gagging  Bite block Tracheal ‡ Extend beyond the pharynx, into the trachea  Endotracheal tubes  Oral or nasal insertion  Tracheostomy tubes  Surgically inserted

Advantages and Disadvantages ‡ Table 30-1 Endotracheal Tubes ‡ Semirigid tubes (polyvinyl chloride) ‡ American Society for Testing and Materials ‡ Standard adapter with a 15 mm external diameter ‡ Length marking ‡ Beveled tube tip ‡ ³murphy eye´ ‡ Tube cuff²seals off lower airway ‡ Pilot balloon²monitor cuff status ‡ Radiopaque indicator Endotracheal Tube

Special Endotracheal Tube

‡ Double lumen endotracheal tube  Independent lung ventilation Tracheostomy Tubes ‡ Plastic polymer, silver ‡ ASTM ‡ Outer cannula ‡ Cuff ‡ Flange ‡ Removable inner cannula with a 15 mm adapter ‡ Pilot balloon ‡ Fenestration (some) ‡ Obturator Jackson tracheostomy tube ‡ Silver ‡ No cuff or 15 mm adapter ‡ Long term airway patients who don¶t need to protect their airway from aspiration or need positive pressure ventilation ‡ Needs an adapter for mechanical ventilation Tracheostomy Tube Jackson Placement ‡ Tube size (average)  Adult female #8 19-21 cm at teeth  Adult male #9 21-23 at teeth ‡ Tube position ideally about 5 cm above the carina

Tracheotomy ‡ Procedure is a tracheostomy ‡ Primary route for overcoming upper airway obstruction or trauma or for long term care of patients with neuromuscular disease ‡ Patients needing an artificial airway for a prolonged period of time ‡ Completed by a surgeon ‡ Box 30-5 Airway Trauma with Tracheal Tubes ‡ Does not conform exactly to patient¶s anatomy ‡ Creates pressure on soft tissue ‡ Can result in ischemia and ulceration ‡ Also can have friction-like injuries due to airway movement as the patient¶s head or neck moves ‡ Damage can occur from the nose down to the lower trachea ‡ Evaluate for injury post extubation Prevention ‡ Limiting tube movement ‡ Limiting cuff pressures ‡ Sterile technique to prevent infection Airway Maintenance ‡ Securing the tube and ensuring proper placement ‡ Providing for patient communication ‡ Ensure adequate humidification ‡ Minimizing risk of infection ‡ Aiding secretion clearance Aiding secretion clearance ‡ Cuff care ‡ Trouble-shooting airway related problems Securing the tube and ensuring proper placement

‡ Cloth tape ‡ Trach ties nd th ‡ 4-6 cm above carina (tube) or 2 -4 tracheal rings (trach) ‡ Movement of neck moves tubes  Flexion down to carina; extension up to larynx  Chest x-rays Securing the Tube Providing for patient communication ‡ Frustrating for patient and caregiver ‡ Lipreading ‡ Letter or picture board ‡ Talking trach tubes ‡ Passey-Muir Valve  Spontaneous or vent patients

Ensure adequate humidification ‡ Artificial tracheal airways bypass the normal humidification, filtration, and heating functions ‡ Decreased humidity causes secretions to thicken ‡ Use heated humidifier or jet nebulizer; HME Minimizing risk of infection ‡ Patients with tracheal airways are susceptible to bacterial colonization and infection ‡ Changes in sputum, breath sounds, x-ray, fever, leukocytosis ‡ Adhere to sterile technique ‡ Aseptic technique ‡ Wash hands ‡ Box 30-7 Facilitating secretion clearance ‡ Suctioning Provide cuff care ‡ Cuffs seal the airway for mechanical ventilation and to prevent aspiration ‡ We use high volume; low-pressure cuffs now  Cuffs do not need to be fully inflated to seal the airway  Maintain pressures of 20-25 mmHg or 25-30 cm H2O  Use the lowest inflation pressure to obtain a satisfactory seal Alternative Cuff Design ‡ Lanz tube  Limits cuff pressure between 16-18 mm Hg with an external pressure regulator ‡ Foam Cuff  Deflate before insertion; never add air Trach Care ‡ Daily care ‡ Equipment (Box 30-8) ‡ Suction ‡ Inner cannula ‡ Stoma ‡ Change ties ‡ Replace inner cannula ‡ Reassess patient Changing a Tracheostomy Tube ‡ Initial performed by surgeon ‡ Subsequent may be performed by RT Troubleshooting Indicators ‡ Inability to pass a suction catheter (obstruction) ‡ Airflow around the tube (leaky cuff) ‡ Always keep replacement airways at the bedside, manual resucitator, mask, gauze pads (to cover tracheostomy)

Obstruction ‡ Kinking of or biting on the tube ‡ Herniation of cuff over tube tip ‡ Jamming of tube orifice against tracheal wall ‡ Mucus plugging ‡ Signs  Decreased breath sounds, increased PIP Obstruction Fix the Problem ‡ Reposition patient ‡ Deflate cuff and attempt to pass catheter ‡ Suction patient ‡ Remove the inner cannula from a trach ‡ May need to remove and replace airway Cuff Leaks ‡ Large leak has a rapid onset ‡ Small leaks will reveal decreasing cuff pressure over time ‡ Adjust position of tube ‡ May need replaced Accidental Extubation ‡ Notice decreased breath sounds, decreased airflow, no cough with suctioning ‡ Replace

Trach Tubes ‡ Fenestrated Tracheostomy Tubes ‡ Tracheal Button

The End