Humidity and Aerosol Therapy Aerosol and Humidity 1

© VikaSuh/ShutterStock, Inc. 26/09/14 5:13 PM - The absolute humidity of a vol- absolute : The The presence of moisture in its of moisture The presence molecu - Humidity: lar form in a gas or gas mixture in a vol- of The weight humidity: water Absolute ume of gas or gas expressed as mixture milligrams per (mg/L) liter Relative humidity ume of gas expressed as water of the a percentage vapor capacity gas of the (i.e., capacity is absolute vapor). with water when saturated humidity ■ ■ ■ Thisdescribes chapter the variousdevices currently proceedingBefore any further, is it important that ■ ■ ■ ing airways the of lower and alveoli that inspired gases regarding the multitude devices of available such for use in the clinical arena.respiratory The therapist’s understanding the of classifications,principles of operation, range of applications, specifications, and hazards these of devices is as important as the therapies these devices are intended to provide. used in the clinical practice providing of humidity and therapies aerosol in spontaneously breathing and mechanically ventilated patients. termssome are defined: Heat Control of Physiologic and Moisture respiratory upper The tract system, and in particular the nose, has the essential function conditioning of inspired gases optimal for and heat moisture before they flow through bronchial the tree expandand the lung parenchyma. is It crucial the function proper for - 4 Chapter - Mohamad F. El-Khatib Mohamad F.

nebulizer (VMN) Large volume jet volume jet Large Passover humidifier Relative humidity Vibrating mesh nebulizer Understand the principle of operation of different types of humidifiers used in clinical practices. humidification. inadequate of consequences the Recognize Compare the different types ofhumidifiers. Compare and contrast the different types of humidifiers in terms of their characteristics. and applications, functions, Describe the natural physiologic humidification process. physiologic natural the Describe humidity for contraindications and Identify indications therapy.

It isIt essential that respiratory care practitioners exchangers (HMEs) Humidity and Aerosol Therapy Aerosol and Humidity 1. 5. 4. 3. 2. cal ventilation. onlynot a firm have understandingof the rationale, physiological basis,indications, and contraindications humidityfor and therapies, aerosol also but a have good grasp the of different technical considerations pies topies patients are who either spontaneously breathing receivingor invasive ventilatory support with mechani Introduction Providing humidity and aerosol therapies are common practices inrespiratory theof field care.Respiratory care practitioners are often in charge the of tasks to provide optimal humidity and efficient aerosolthera KEY TERMS therapy Aerosol Bubble humidifier Heat and moisture Heated humidifier Humidification CHAPTER OBJECTIVES CHAPTER 9781449601942_CH04_PASS02.indd 75 76 CHAPTER 4 Humidity and Aerosol Therapy

are fully saturated with water vapor and warmed to medical gases are indicated and needed to prevent a body temperature upon reaching just below the carina. negative impact on a patient’s health. The recommended This point in the upper airways is called the isother- humidity and heat levels are shown in Table 4-1. mic saturation boundary (ISB). At this boundary, the inspired gas should have 100% relative humidity and a Effects of Inadequate temperature of 98.6°F (37°C). Humidification During inspiration, the induced turbulence in the flow of the inspired gas as it passes through the nasal The objective of humidity therapy is to condition medi- turbinates increases the contact between the molecules cal gases to approximate normal inspiratory condi- of inspired gas and the nasal mucosa and results in tions. With proper humidification, the ISB remains just efficient warming of the inspired gas. This is called below the carina with no downward shift toward the turbulent convection. With the efficient warming of small airways. Extrinsic humidification and heating of the inspired gas, water is then transferred and added inspired dry medical gases should be ensured (whether to the inspired gas by evaporation from the mucosa. the nose and upper airways are bypassed or not) during Evaporation results in cooling and decreasing the different modalities of respiratory support using either water content of the tracheal and nasal mucosa. During medical gas therapies or invasive and noninvasive ven- expiration and as the gas is exhaled, the tracheal and tilator support. Inadequate humidification can result nasal mucosa cools the exhaled gas and reclaims part of in substantial water and heat loss from the airways that its water content. This is called condensation. can lead to the disruption of the mucociliary trans- Below the isothermic saturation boundary, tempera- port system and an increase in mucus production with ture and relative humidity remain constant with body thickening of the pulmonary secretions, an increase in temperature and pressure, saturated (BTPS) conditions the airway irritability, and ultimately structural damage (i.e., 98.6°F [37°C] body temperature, barometric pres- to the lung.2 sure, and 100% relative humidity). When the ISB is not There are several signs and symptoms of inadequate achieved just below the carina, there will be a further humidification.3 These are more evident and significant distal downshift in the ISB. Several clinical and tech- during invasive mechanical ventilation when the nical conditions can lead to such displacement of the normal water and heat exchange capabilities of upper ISB.1 These include situations when patients breathe airways are bypassed with the use of endotracheal cold and dry air, as when breathing medical gases pro- tubes. The clinical signs and symptoms usually include vided by hospitals’ medical gas supply systems; when thick, dehydrated, and encrusted secretions; dry and patients breathe through their mouths at higher minute nonproductive cough; patient complaint of substernal ventilation, which is mostly the case during respiratory pain; atelectasis; increased incidence of infection; distress situations; or when patients’ natural anatomi- bacterial infiltration of mucosa; increased airway cal humidification and heating structures are bypassed resistance; and increased work of breathing. by artificial airways or endotracheal tubes during mechanical ventilation. With the distal shift of the Application ISB, additional surfaces from the lower airways will be Indications for Humidity Therapy required to provide humidity and heat. This can nega- tively impact the epithelial integrity of these airways, Humidity and heat therapy is administered during make them susceptible to infection and inflammation, numerous respiratory care therapeutic modalities to and lead to the narrowing of their cross-sectional areas.2 a wide variety of patients under different clinical sce- As such, whenever the body’s capability for humidify- narios and medical conditions. This can be provided ing and heating inspired gas is compromised, external in both the hospital and home setting. The gener- measures for humidifying and heating of these inspired ally accepted indication for this type of therapy is

TABLE 4-1 Recommended Heat and Humidity Levels

Site Temperature Range (°C) Relative Humidity (%) Absolute Humidity (mg/L)

Nose/mouth 20–22 50 10

Hypopharynx 29–32 95 28–34

Trachea 32–35 100 36–40

Carina 37 100 44

Reproduced from Chatburn R, Primiano F. A rational basis for humidity therapy. Respir Care. 198;32:249, 1987; permission conveyed through Copyright Clearance Center, Inc.

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TABLE 4-2 Indications for Humidity Therapy

1. Delivering adequate humidity when spontaneously breathing medical gases for therapeutic purposes 2. Providing adequate humidification in the presence of artificial airway during invasive mechanical ventilation 3. Providing adequate humidification in the presence of high gas flows during noninvasive ventilation and high flow nasal cannula oxygen therapy 4. Thinning dried and/or thick secretions 5. Promoting bronchial hygiene 6. Managing hypothermia in intubated and mechanically ventilated patients 7. Treating bronchospasm caused by cold air in spontaneously breathing patients

conditioning the dry inspired mix of medical gases, environment when breathing circuits are disconnected particularly when the normal and anatomical structures while the ventilator is generating high flows.7 of the body (nose and upper airways) are either com- With HMEs, there are risks for hypothermia; pos- promised or bypassed.4 The different indications for sible increase in the resistive work of breathing through humidity therapy are summarized in Table 4-2. the HME, particularly after long use (> 24 hours); and possible hypoventilation due to increased mechanical Contraindications for Humidity Therapy dead space.8 In general, there are no contraindications to providing Monitoring Therapeutic Effectiveness humidification of inspired gas during spontaneous breathing or mechanical ventilation. However, there The primary goal for humidity therapy is to condition might be some contraindications for using certain medical gases to achieve normal inspiratory conditions humidification devices during specific clinical of 100% relative humidity and 98.6°F (37°C) just conditions.5 A heat and moisture exchanger (HME) below the carina and before the medical gases enter is contraindicated in patients with thick, copious, or the airways. Ideal measurement and monitoring of bloody secretions. A minute ventilation greater than the therapeutic effectiveness of humidity therapy 10 L/min is a contraindication for the use of an HME requires the placement of a hygrometer (a device that as the means for providing humidification during measures humidity) and a thermometer at the level of ventilator support. Also, HMEs are contraindicated the carina. Currently this is not available; the closest in patients with expired tidal volume less than 70% point for measurement of these parameters is at the of the delivered tidal volume, such as in patients with patient Y for mechanically ventilated patients and the large bronchopleural fistulas, severe tracheomalasia, mouth opening for spontaneously breathing patients. or uncuffed endotracheal tubes. The use of heat and However, hygrometers are not widely used in clinical moisture might also be contraindicated in patients with practice; most of the time the temperature is measured body temperature of less than 89.6°F (32°C). Unless and monitored at the patient’s Y during mechanical it is bypassed, the HME has to be removed from the ventilation. Therefore, monitoring therapeutic patient's breathing circuits when he or she is receiving effectiveness of humidity therapy is not direct and in-line aerosol drug treatments. remains mainly subjective and widely dependent on the careful qualitative assessment of the patient and Hazards of Humidity Therapy patient's breath sounds, patient's cough along with the characteristics of the sputum expectorated, and Hazards and complications encountered during secretions and formation of mucus plugs as surrogates humidification therapy are infrequent and mainly for effective humidification therapy.9 In general, the associated with the use of the humidification devices 6 absence of underhydration, thick secretions, mucus rather than the therapy itself. With the use of plugging of airways, obstruction of the endotracheal heated humidifiers , there are potentials of electrical or tracheostomy tube, and mechanical ventilation– shock, hyperthermia, thermal injury to the airways, induced inflammatory responses, along with normal tubing meltdown if circuits and heated humidifiers are breath sounds can be considered as signs of effective incompatible, burns to caregivers from the humidifier’s humidity therapy. hot metal, and pooled condensation in the patient’s breathing circuits. With excessive pooled condensation, there will be risks for patient–ventilator dysynchrony Active Humidifiers and improper ventilator performance, elevated airway Active humidification can be accomplished using either pressures, inadvertent tracheal lavage from pooled bubble, passover, or heated humidifiers. The levels of condensation or overfilling of humidifier, and nosocomial humidification achieved with these humidifiers depend infection for both patients and clinicians when greatly on the design and principle of operation of each pooled condensates are aerosolized into the patient's of these devices.

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Hazards: If heated, bubble humidifiers result in excessive condensate that tends to obstruct the small bore delivery tubing that connects between the humidifier output and the patient's interface. With prolonged use, there is a risk that the pressure relief valve becomes dysfunctional, which can lead to the build-up of excessive pressures and burst the humidifier bottle whenever a flow obstruction occurs. Whenever high flow rates (usually in excess of 10 L/min) are used, bubble humidifiers can produce aerosols. These water droplets can transmit pathogenic bacteria from the humidifier reservoir to the patient. Principles of operation: As inspired medical gases leave the diffuser and enter the water, gas bubbles are formed that flow through the liquid. This allows for greater exposure time and contact A area, thereby increasing the capability of the flowing dry medical gases to extract humidity from the water. With these types of unheated bubble humidifiers, an absolute humidity level between approximately 15 and 20 mg/L is usually achieved. Bubble humidifier units function at a flow rate of 2 L/min and should not be operated at greater than 6 L/min because they start to lose their efficiency in providing humidity. The higher the flow rate, the less exposure time B in the water medium and the higher risk for cooling the reservoir.11 These humidifiers are not FIGURE 4-1 Simple bubble jet humidifiers: A. Disposable. B. recommended for use at flow rates greater than Prefilled. 10 L/min. In the event of a flow obstruction out Photo A courtesy of Teleflex. Photo B courtesy of Smiths Medical. of the humidifier bottle, the pressure relief valve opens and releases pressure from inside the bottle while giving an audible alarm. Once the flow Bubble Humidifiers obstruction is eliminated, the pressure relief valve A bubble humidifier consists of a bottle or reservoir automatically resumes its normal position. partially filled with water attached to a conduction Currently available devices: Bubble humidifiers remain system that allows the inspired medical gases to be widely used in the practice of respiratory care. introduced below the water surface. A diffuser that is Almost every single patient using low flow usually either a foam or a metallic mesh is attached to oxygen therapy via a nasal cannula or a face the end of the conduction system. Bubble humidifiers mask will need a bubble humidifier. There are are either reusable or single patient use humidifiers.10 many commercially available bubble humidifiers Furthermore, single patient use humidifiers are either with different specifications, as presented in dry or prefilled. Bubble humidifiers incorporate a Table 4-3. pressure relief valve that releases pressure from inside the humidifier bottle to prevent bursting of the bubble in the event there is an obstruction to the flow path Passover Humidifiers out of the humidifier bottle. Usually these pressure These are mainly of three types: the simple passover, relief valves function at a pressure of greater than 2 psi. the wick, and the membrane device (Figure 4-2). The Bubble humidifiers are also known as bubble diffuser simple passover humidifier is just a reservoir/jar con- humidifiers or just diffusers (Figure 4-1). taining water over which the dry inspired gas will flow Indications: The bubble humidifier is used to humidify and increase its water content. The wick humidifier the inspired medical gases delivered to patients via consists of a reservoir in addition to a porous material a cannula or face mask. (wick) that absorbs water and provides a larger area Contraindications: This type of humidifier is contrain- for air-water mix for better evaporation. Some of these dicated for patients with an endotracheal tube, a wick humidifiers include a fan to aid in the evaporation tracheostomy, or tenacious secretions. of the water.

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TABLE 4-3 Types and Specifications of Bubble Humidifiers

Sterile/ Audible Safety Pressure- Product Name/ Closed Volume Pressure- Relief Min/Max Manufacturer Number Type System (mL) Relief Valve Level (psi) Indicators Lid Nut Diffuser Heater

Afton Medical 80300 Dry-disposable No 300 Yes 3 Yes Plastic Plastic NS No

80400 Dry-disposable No 400 Yes 4 Yes Plastic Plastic NS No

80600 Dry-disposable No 400 Yes 6 Yes Plastic Plastic NS No

Allied Health Care 64375 Dry-disposable No 300 Yes 3 Yes Plastic Plastic Foam No Products, Inc.

64376 Dry-disposable No 300 Yes 3 Yes Plastic Metal Foam No

64377 Dry-disposable No 300 Yes 6 Yes Plastic Plastic Foam No

64378 Dry-disposable No 300 Yes 6 Yes Plastic Metal Foam No

61350S Prefilled-disposable Yes 350 Yes 6 N/A Plastic Plastic Foam No

61550S Prefilled-disposable Yes 350 Yes 6 N/A Plastic Plastic Foam No

34-10-0001 Dry-reusable No NS NS NS Yes Plastic Plastic Metal No

34-10-0005 Dry-reusable No NS Yes NS Yes Plastic Plastic Metal No

34-10-0025 Dry-reusable No NS Yes NS Yes Plastic Plastic Metal No

Besmed HB-1130 Dry-disposable No 300 Yes 3 Yes Plastic Plastic PVC or ceramic No

HB-1132 Dry-disposable No 500 Yes 4 Yes Plastic Plastic PVC or ceramic No

HB-2401 Dry-disposable No 400 Yes 6 Yes Plastic Plastic PVC or ceramic No

HB-2411 Dry-disposable No 400 Yes 4 Yes Plastic Plastic PVC or ceramic No Active Humidifiers

HB-2601 Dry-disposable No 400 Yes 6 Yes Plastic Plastic PVC or ceramic No

HB-2611 Dry-disposable No 400 Yes 4 Yes Plastic Plastic PVC or ceramic No

(continues) 26/09/14 5:13 PM 79 9781449601942_CH04_PASS02.indd 80 80 CHAPTER 4 Humidity andAerosol Therapy

TABLE 4-3 Types and Specifications of Bubble Humidifiers (Continued)

Sterile/ Audible Safety Pressure- Product Name/ Closed Volume Pressure- Relief Min/Max Manufacturer Number Type System (mL) Relief Valve Level (psi) Indicators Lid Nut Diffuser Heater

CareFusion AirLife 2620 Prefilled-disposable Yes 500 Yes 4 N/A Plastic Plastic NS No

AirLife 2702 Prefilled-disposable Yes 750 Yes 4 N/A Plastic Plastic NS No

AirLife 2003 Dry-disposable No 370 Yes 3 Yes Plastic Plastic Foam No

Carefusion AirLife 2006 Dry-disposable No 370 Yes 6 Yes Plastic Plastic Foam No

Galemed BH-1 Dry-disposable No NS Yes 2, 4, or 6 Yes Plastic Plastic NS No

BH-2 Dry-disposable No NS Yes 2 Yes Plastic Plastic NS Yes

BH-3 Dry-disposable No NS Yes 4 Yes Plastic Plastic NS No

ECO Dry-disposable No NS Yes 4 Yes Plastic Plastic NS No

Genstar Technologies, 7100R Dry-reusable No 300 Yes NS Yes Plastic Plastic NS No Inc.

7200R Dry-reusable No 140 No NS Yes Metal Metal NS No

638-001 Dry-disposable No 250 Yes NS Yes Plastic Plastic NS No

638-002 Dry-disposable No 400 Yes NS Yes Plastic Plastic NS No

638-003 Dry-disposable No 400 Yes NS Yes Plastic Plastic NS No

GF Health Products, Inc. BF61550S Prefilled-disposable Yes 550 Yes 6 N/A Plastic Plastic NS No

GF64375 Dry-disposable No 250 Yes 6 Yes Plastic Plastic NS No 26/09/14 5:13 PM 9781449601942_CH04_PASS02.indd 81

TABLE 4-3 Types and Specifications of Bubble Humidifiers

Sterile/ Audible Safety Pressure- Product Name/ Closed Volume Pressure- Relief Min/Max Manufacturer Number Type System (mL) Relief Valve Level (psi) Indicators Lid Nut Diffuser Heater

Intersurgical AquaFlow 1507 Dry-disposable No 120 & Yes NS Yes Plastic Plastic NS No 500

AquaFlow 1521 Dry-disposable No 120 Yes NS Yes Plastic Plastic NS No

Ohio Medical Corp. 6700-0338-800 Dry-reusable No 300 Yes 2 Yes Plastic Plastic Chrome-plated No brass

Salter Labs 7100 Dry-disposable No 350 Yes 3 Yes Plastic Plastic PVC No

7600 Dry-disposable No 350 Yes 6 Yes Plastic Plastic PVC No

7900 Dry-disposable No 350 Yes NS Yes Plastic Plastic PVC No

Teleflex 003-40 Prefilled-disposable Yes 340 Yes NS N/A Plastic Plastic NS No

005-40 Prefilled-disposable Yes 540 Yes NS N/A Plastic Plastic NS No

006-40 Prefilled-disposable Yes 650 Yes NS N/A Plastic Plastic NS No

3230 Dry-disposable No 500 Yes 4 Yes Plastic Plastic NS No

3260 Dry-disposable No 500 Yes 6 Yes Plastic Plastic NS No

Ventlab Corp. VTB6900 Dry-disposable No 350 NS NS Yes Plastic Plastic NS NS

Westmed 0480 Dry-disposable No NS Yes NS Yes Plastic Plastic PVC No

0795 Dry-disposable No NS Yes NS Yes Plastic Plastic PVC No Active Humidifiers

N/A: Not applicable, NS: Not specified,P VC: Polyvinylchloride 26/09/14 5:13 PM 81 82 CHAPTER 4 Humidity and Aerosol Therapy

Contraindications: There are no contraindications for using passover humidification to provide physiologic conditioning of inspired gas during invasive and noninvasive mechanical ventilation.14 Hazards: Passover humidifiers have minimal hazards. However, if a heat element is used, then there will be the risk of electrical shock. Hypo- or hyperthermia can result from inadequate adjustment of the temperature. Excessive heating and evaporation can result in accumulation of condensate in the breathing circuit with the risk of contamination, patient–ventilator asynchrony, and condensate aerosolization whenever the patient is disconnected from the ventilator. In addition, if the compressible volume losses from the humidifier A reservoir are not compensated for, there is a risk for inaccurate tidal volume measurement. Principles of operation: As the inspired gases pass over the water surface and hydrophobic membrane, the water vapor can easily pass through the wick or membrane, mix with the dry inspired gas, and increase its water content. Liquid water will not cross the hydrophobic membrane. Currently available devices: Passover humidifiers are very common during invasive and noninvasive mechanical ventilation. There are several commercially available passover humidifiers with different specifications and features, as presented in Table 4-4.

B Heated Humidifiers FIGURE 4-2 Different types of passover humidifiers: A. Simple. A heated humidifier consists of a reservoir and a B. Wick type. heating element. Some heated humidifiers include Photo A reproduced with permission from Philips Healthcare. a wick element. The wick is usually surrounded by the heating element to maintain adequate saturation of the wick during the operation of the device.15 The Membrane Devices heating element improves water output and usually has a controller that regulates the element's heating Membrane passover humidifiers consist of a jar that power and subsequently maintains a set temperature can be filled with water with no conduction system of inspired gas at the patient airway. These systems for the inspired gas inside the jar. A hydrophobic incorporate alarms and alarm-activated heater membrane separates the gas stream from the water. shutdown. Inspired gases flow in one side, pass over the water There are four different types of heating systems: surface and membrane, and exit from another side of the humidifier. There is no bubbling of water inside ■■ A hot plate located at the base of the humidifier the humidifier. The efficiency of this unit is rather low, chamber because exposure area and time of contact are limited ■■ A wraparound that surrounds the humidifier and the water is usually not heated. Membrane passover chamber humidifiers can maintain saturation at high flow rates ■■ A collar that sits between the water reservoir and with no or little resistance to spontaneous breathing the gas outlet circuits.12 Additionally they do not generate aerosols, ■■ An immersion type where the heating element is leading to minimal risk for spreading infection. placed in the water

Indications: Passover humidifiers are usually used with All modern heated humidifiers are equipped with invasive and noninvasive ventilator support (e.g., automatic feed systems with a flotation valve control nasal continuous positive airway pressure or bilevel for adequate and continuous control of the water level positive airway pressure support).13 inside the humidifier chamber (Figure 4-3).

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TABLE 4-4 Types and Specifications of Passover Humidifiers

Product Sterile/ Audible Safety Pressure- Name/ Closed Volume Pressure- Relief Level Min/Max Heater Manufacturer Number Type System (mL) Relief Valve (psi) Indicators Lid Nut Diffuser Interface

Afton Medical 80300 Dry-disposable No 300 Yes 3 Yes Plastic Plastic NS No

80400 Dry-disposable No 400 Yes 4 Yes Plastic Plastic NS No

80600 Dry-disposable No 400 Yes 6 Yes Plastic Plastic NS No

Allied Health Care 64375 Dry-disposable No 300 Yes 3 Yes Plastic Plastic Foam No Products, Inc.

64376 Dry-disposable No 300 Yes 3 Yes Plastic Metal Foam No

64377 Dry-disposable No 300 Yes 6 Yes Plastic Plastic Foam No

64378 Dry-disposable No 300 Yes 6 Yes Plastic Metal Foam No

61350S Prefilled-disposable Yes 350 Yes 6 N/A Plastic Plastic Foam No

61550S Prefilled-disposable Yes 350 Yes 6 N/A Plastic Plastic Foam No

34-10-0001 Dry-reusable No NS NS NS Yes Plastic Plastic Metal No

34-10-0005 Dry-reusable No NS Yes NS Yes Plastic Plastic Metal No

34-10-0025 Dry-reusable No NS Yes NS Yes Plastic Plastic Metal No

Besmed HB-1130 Dry-disposable No 300 Yes 3 Yes Plastic Plastic PVC or Ceramic No

HB-1132 Dry-disposable No 500 Yes 4 Yes Plastic Plastic PVC or Ceramic No

HB-2401 Dry-disposable No 400 Yes 6 Yes Plastic Plastic PVC or Ceramic No

HB-2411 Dry-disposable No 400 Yes 4 Yes Plastic Plastic PVC or Ceramic No

HB-2601 Dry-disposable No 400 Yes 6 Yes Plastic Plastic PVC or Ceramic No

HB-2611 Dry-disposable No 400 Yes 4 Yes Plastic Plastic PVC or Ceramic No Active Humidifiers

CareFusion AirLife 2620 Prefilled-disposable Yes 500 Yes 4 N/A Plastic Plastic NS No

AirLife 2702 Prefilled-disposable Yes 750 Yes 4 N/A Plastic Plastic NS No

AirLife 2003 Dry-disposable No 370 Yes 3 Yes Plastic Plastic Foam No

AirLife 2006 Dry-disposable No 370 Yes 6 Yes Plastic Plastic Foam No 26/09/14 5:13 PM

(continues) 83 9781449601942_CH04_PASS02.indd 84 84

TABLE 4-4

Types and Specifications of Passover Humidifiers (Continued) CHAPTER 4

Product Sterile/ Audible Safety Pressure- Name/ Closed Volume Pressure- Relief Level Min/Max Heater Manufacturer Number Type System (mL) Relief Valve (psi) Indicators Lid Nut Diffuser Interface

Galemed BH-1 Dry-Disposable No NS Yes 2, 4, or 6 Yes Plastic Plastic NS No Humidity andAerosol Therapy

BH-2 Dry-Disposable No NS Yes 2 Yes Plastic Plastic NS Yes

BH-3 Dry-Disposable No NS Yes 4 Yes Plastic Plastic NS No

ECO Dry-Disposable No NS Yes 4 Yes Plastic Plastic NS No

Genstar 7100R Dry-Reusable No 300 Yes NS Yes Plastic Plastic NS No Technologies, Inc

7200R Dry-Reusable No 140 No NS Yes Metal Metal NS No

638-001 Dry-Disposable No 250 Yes NS Yes Plastic Plastic NS No

638-002 Dry-Disposable No 400 Yes NS Yes Plastic Plastic NS No

638-003 Dry-Disposable No 400 Yes NS Yes Plastic Plastic NS No

GF Health Products, BF61550S Prefilled-Disposable Yes 550 Yes 6 N/A Plastic Plastic NS No Inc.

GF64375 Dry-Disposable No 250 Yes 6 Yes Plastic Plastic NS No

Ohio Medical Corp. 6700-0338- Dry-Reusable No 300 Yes 2 Yes Plastic Plastic Chrome-plated No 800 brass

Salter Labs 7100 Dry-Disposable No 350 Yes 3 Yes Plastic Plastic PVC No

7600 Dry-Disposable No 350 Yes 6 Yes Plastic Plastic PVC No

7900 Dry-Disposable No 350 Yes NS Yes Plastic Plastic PVC No

Teleflex 003-40 Prefilled-Disposable Yes 340 Yes NS N/A Plastic Plastic NS No

005-40 Prefilled-Disposable Yes 540 Yes NS N/A Plastic Plastic NS No

006-40 Prefilled-Disposable Yes 650 Yes NS N/A Plastic Plastic NS No

3230 Dry-Disposable No 500 Yes 4 Yes Plastic Plastic NS No

3260 Dry-Disposable No 500 Yes 6 Yes Plastic Plastic NS No

Ventlab Corp. VTB6900 Dry-Disposable No 350 NS NS Yes Plastic Plastic NS NS

Westmed 0480 Dry-Disposable No NS Yes NS Yes Plastic Plastic PVC No

0795 Dry-Disposable No NS Yes NS Yes Plastic Plastic PVC No 26/09/14 5:13 PM N/A: Not applicable, NS: Not specified, PVC: Polyvinylchloride Aerosol Generators 85

Similar to membrane device passover humidifiers, can result in patient–ventilator asynchrony or no bubbling occurs and subsequently no aerosol is unintentional tracheal lavage or can be aerosolized produced. when disconnecting the patient from the mechanical ventilator, which can put the patient Indications: Heated humidifiers provide a high level of and the caregiver at risk for nosocomial infection. humidity and heat, and for that reason are mainly Because the chambers of these humidifiers can used with intubated and mechanically ventilated be of substantial volume, the compressible volume 16 patients. In these patients, the upper airways losses should be compensated for; otherwise, are bypassed by the endotracheal tubes and the inaccurate tidal volume is measured with a patients are fully dependent on external sources decrease in the ventilator response.17 that provide the highest possible levels of humidity Principles of operation: During operation, the heating and heat for optimal conditioning of the inspired element, which is usually either a plate or a rod, gases. increases and maintains the water temperature in Contraindications: There are no contraindications the reservoir at 37–38°C via a servo controlled for using heated humidifiers in order to provide closed system. The dry and cold gas passes over physiologic conditioning of inspired gas during the heated and warm water before being expelled invasive mechanical ventilation. out of the water reservoir during inspiration and Hazards: Like with any other electrical devices, more humidification takes place. This device can there will always be a risk of electrical shock. If deliver 100% relative humidity. the temperature is not adequately set, heated Currently available devices: The currently available humidifiers can result in hypo- or hyperthermia. commercial devices do not include wick elements. Thermal injury to the airway can occur from The systems are passover humidifiers with either heated humidifiers; in addition, burns to the patient a heated plate chamber or a heated wire chamber. and to the caregiver and tubing meltdown can The specifications of commercially available heated result if heated-wire circuits are covered or circuits humidifiers are presented in Table 4-5. and heated humidifiers are incompatible. Pooled contaminated condensate in the breathing circuit Aerosol Generators Aerosol generators are required for the delivery of sterile water or hypotonic, isotonic, or hypertonic saline aerosols. During bland aerosol therapy, liquid particles are generated and delivered to the patient's airway suspended in the inspired gas.18 Several devices can be used for aerosol generation during bland aerosol therapy. The most common are the large volume jet nebulizers and vibrating mesh or “ultrasonic” nebulizers. Large Volume Jet Nebulizer The use oflarge volume jet nebulizers is very common in respiratory care practice. Large volume jet nebulizers are pneumatically powered with direct attachment to a flowmeter and compressed gas source. These devices deliver cool or heated aerosols with the possibility for precisely regulating inspired oxygen concentrations by using a variable oxygen diluter (Figure 4-4). When using these units, the flow selected should always match or exceed the patient's peak inspiratory flow rates.18,19 Similar to heated humidifiers, a hot plate or immersion element can be added if active heating of the inspired gas is required. These devices rarely have automatic servo-controlled systems to control delivered inspired gas temperature. Depending on the design, flow, and air entrainment setting, the total water output of unheated FIGURE 4-3 Heated humidifiers. large volume jet nebulizers varies between 26 mg H2O/L Courtesy of Fisher & Paykel Healthcare. and 35 mg H2O/L. However, when heated, output can be

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TABLE 4-5 Types and Specifications of Heated Humidifiers

Product Integrated Relative Name/ Flow Flow Disinfection Temperature Humidity Overheat Weight

Manufacturer Number Generator Patients O2 Range Range Kit Range Indicator Protection Dimensions (lb)

Fisher & Paykel AIRVO 2 Yes Spontaneously 21–80% 5–50 L/min Yes 37ºC No No 11.6" x 6.7" x 6.9" 4.6 Healthcare breathing—in hospital

myAIRVO2 Yes Spontaneously No precise 5–50 L/min Yes 37ºC No No 11.6" x 6.7" x 6.9" 4.8 breathing—home control

HC150 N/A Spontaneously N/A N/A N/A 30ºC–65ºC No No 2.1" x 5.2" x 5.7" 1.8 breathing—CPAP/ BiPAP

MR850 N/A All groups N/A N/A N/A 10ºC–70ºC No Yes 5.6" x 6.9" x 5.4" 6.3

Galemed HumiAIDE 7 N/A All groups N/A N/A N/A 10ºC–40ºC Yes Yes 5.8" x 5.6" x 7.2" 2.9

HumiAIDE 5 Yes Spontaneously N/A NS NS 10ºC–40ºC Yes Yes 5.8" x 5.6" x 7.2" 0.55 breathing—home

64377

Smiths-Medical Thera-Heat N/A All groups N/A N/A N/A NS Yes NS NS NS

Vapotherm, Inc. Vapotherm Yes Spontaneously 21–100% 1–40 L/min NS 33ºC–43ºC N/A Yes 11.5" x 8" x 7" 12 breathing—in hospital

N/A: Not applicable, NS: Not specified 26/09/14 5:13 PM Aerosol Generators 87

DISS flowmeter inlet

Variable air entrainment port

Jet orifice Outlet port

Siphon tube

Water reservoir

Filter

A B

C D

FIGURE 4-4 Large volume jet nebulizer: A. Schematic. B. Dry disposable. C. Heated disposable. D. Prefilled heated disposable. Photo B reproduced with permission from CareFusion. Photo C courtesy of Teleflex. Photo D coutesy of Teleflex.

with large volume jet nebulizers is indicated increased to between 33 mg H2O/L and 55 mg H2O/L. If aerosols are delivered into mist tents, volume jet in patients with laryngotracheobronchitis and nebulizers with reservoirs of 2–3 liters are used. whenever mobilization of secretions and sputum specimens are needed. Indications: There are several clinical conditions that Contraindications: In patients with a history of upper warrant the use of large volume jet nebulizers.18,20 airway hyper-responsiveness and those who Cool bland aerosol is indicated in the presence are at risk for bronchorestriction, bland aerosol of upper airway edema, subglottic edema, and generation with a large volume jet nebulizer is postextubation edema. Furthermore, bland aerosol contraindicated.

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Hazards: The hazards and complications associated carried in the gas stream provided to the patient. with bland aerosol therapy are not related to the Many nebulizers have an air intake or Venturi large volume jet nebulizer per se, but rather to to allow the entrainment of room air for dilution the therapy itself.18,21 Patients might be at risk for of the primary gas, usually oxygen, to be able wheezing or bronchospasm during bland aerosol to provide precise concentration of inspired therapy. Also there is a risk for edema associated oxygen. with decreased compliance and gas exchange Currently available devices: Large volume jet nebuliz- and with increased airway resistance. During ers used to be very common in the practice coughing and sputum induction, the caregivers of respiratory care; however, recent technical will be exposed to airborne contagions, and those developments have led to a decrease in the patients with common respiratory diseases (e.g., dependence on these devices. Some of the chronic obstructive pulmonary disease [COPD], currently available devices are described in asthma, or cystic fibrosis) will be at risk for Table 4-6. bronchoconstriction. When inadequate flow is used, when the siphon tube is obstructed, or when the jet orifices are misaligned, large volume jet nebulizers will Vibrating Mesh Nebulizer produce inadequate mist. Also many systems of Vibrating mesh nebulizers (VMNs) are exceptionally large volume jet nebulizers do not shut down when good at producing very fine aerosols (up to a mass the reservoir is empty, resulting in the delivery of median aerodynamic diameter of 4.5 µm) with higher dry inspired gas to the patient. Finally, some of respirable fraction (RF) at slower velocities and within these systems tend to be noisy. a short time (2–30 minutes) depending on the fill Principles of operation: A large volume jet nebulizer volume and the type of drug being nebulized. VMNs works by directing a high flow of gas (usually a are capable of producing consistently high, efficient mixture of room air and oxygen) through a small aerosol outcomes.23 The integral component of VMNs jet orifice. The low pressure generated at the jet is a vibrating mesh plate, or aperture plate, with high- orifice draws fluid up a siphon tube. Once the precision-formed holes that control the size and flow water level reaches the top, it is removed by of the aerosolized particles (Figure 4-5). Vibrating shear forces. This is a continuous process, and mesh nebulizers operate around 128 KHz. A separate the water removed forms a dense aerosol.18,22 or attached power supply provides electricity (via Generated aerosolized particles are of different batteries or AC power supply) to the vibrating piezo- sizes. Downstream a short distance from the jet electric element. VMNs have medication reservoirs is a baffle that serves to stabilize particle size. and a patient interface (a mouthpiece for spontane- When the aerosolized particles meet the baffle, ously breathing patients and a T-piece adapter that larger unstable particles with higher inertia are fits in-line with the ventilator circuit for intubated rained out and fall back into the reservoir to and mechanically ventilated patients). Because vibrat- minimize waste. The remaining small and stable ing mesh nebulizers do not require an external gas particles leave through the outlet port and get source for nebulization, no additional external flow

TABLE 4-6 Types and Specifications of Large Volume Jet Nebulizers

Product Sterile/ Inspired Oxygen Name/ Closed Volume Oxygen Flow (L/ MMAD Min/Max Heater Manufacturer Number Type System (mL) Range (%) min) (µm) Indicators Interface

CareFusion AitLife 5007p Disposable No 350 28–98 5–11 2.8 Yes No

Galemed Neb-3 Large Disposable No 500 35–100 NS 5 Yes Yes Volume Nebulizer

Intersurgical AquaMist Disposable No 500 28–60 5–11 NS Yes No 1509

Teleflex Large Volume Disposable No 500 28–98 5–10 NS Yes Yes Neb 1770

MMAD: Mass median aerodynamic diameter, NS: Not specified

9781449601942_CH04_PASS02.indd 88 26/09/14 5:13 PM Aerosol Generators 89

Reservoir

PIezo-electric Liquid drug actuator Vibrating mesh

Conical holes

Respirable aerosol

A B

C D

FIGURE 4-5 Vibrating mesh nebulizers: A. Schematic. B. Omron. C. Aerogen. D. Pari. Photo B courtesy of Omron Healthcare. Photo C courtesy of Aerogen. Photo D courtesy of PARI Respiratory Equipment. “eFlow® Technology” are registered trademarks of PARI GmbH.

will be added to the total inspiratory flow provided by drug volumes left in vibrating mesh nebulizers are the ventilator; subsequently, the nebulization process very minimal (0.01 to 0.4 mL depending on reservoir will not interfere with the performance of mechanical design), ensuring adequate doses delivered to patients ventilators. Due to their high efficiency, the residual during treatments. VMNs are more expensive and

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TABLE 4-7 Technical Features and Specifications of Vibrating Mesh Nebulizers

Calculated Medication Respirable Dose Cup Delivered via Product Name/ Capacity MMAD Residual Endotracheal Manufacturer Number Patients (mL) (µm) Volume Tube Mode

Aerogen Aeroneb Go Spontaneously 6 3.6 < 0.3 ml N/A Intermittent breathing

Aeroneb Pro Mechanically 10 2.1 0.3 ml 13% Intermittent ventilated

Aeroneb Solo Mechanically 6 3.4 < 0.1 mL 13–17% Intermittent & ventilated for 3 mL continuous dose

Omron Micro Air NE-U22 Spontaneously 7 4.2 0.1 N/A Intermittent breathing

Pari eRapid Spontaneously NS 4.1 NS N/A Intermittent breathing

MMAD: Mass median aerodynamic diameter

generally more costly to repair than pneumatically are cleaned according to the manufacturer's powered devices, though they are sometimes recommendations and that residual volumes replaceable under a limited warranty by the of solutions are discarded from the reservoir manufacturer. periodically between cleanings. Principles of operation: Vibrating mesh nebulizers work Indications: Vibrating mesh nebulizers are useful for on the principle of high frequency sound waves the treatment of thick secretions that are difficult that can break water into aerosol particles.23,25 to expectorate, and they can help to stimulate a When the power supply is turned on, the piezoelec- cough and sputum induction. In addition to the tric transducer emits vibrations forcing the liquid classical bronchodilators, current evidence sug- solution to pass through the holes and thus produc- gests that vibrating mesh nebulizers can play a ing a dense aerosol at extremely low flow rates. role in nebulizing and delivering directly to the lung Most currently available vibrating mesh nebulizers parenchyma a wide range of medications previously are powered by a preset controller; clinicians 24 known to be delivered only intravenously, such as need only select the duration of the nebulization antibiotics (e.g., aztronam, colistin, tobramycin), process. pulmonary vasodilators (e.g., ilioprost), insulin, Currently available devices: Among the new generation of other proteins and peptides, and fragments of DNA. nebulizers are several devices that employ a vibrating Contraindications: In patients with a history of upper mesh or plate with multiple apertures to generate a airway hyper-responsiveness and those who liquid aerosol. The characteristics and specifications are at risk for bronchorestriction, bland aerosol of these devices are presented in Table 4-7. generation with vibrating mesh nebulizers might be contraindicated. Hazards: Vibrating mesh nebulizers are limited in that they cannot aerosolize viscous solutions. (Sterile Passive Humidifiers water and normal saline are preferred.) Blockage Passive humidifiers are mainly retainers of water vapor of the minute apertures with drug particles can expelled with the exhaled gas from the lungs during result if these devices are not cleaned well. the expiratory phase of a breath. During the inspiratory As with any other nebulizer, the reservoirs of phase of a breath, previously retained water vapor is these devices can easily become contaminated, released into the gas flowing to the patient's lungs. resulting in airborne transmission of pathogens. The main type of passive humidifier is the heat and Care should be taken to ensure that these units moisture exchanger.

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TABLE 4-8 Contraindications for Heat and Moisture Exchangers (HMEs)

Thick, copious, or bloody secretions Expired tidal volume less than 70% of the delivered tidal volume When using low tidal volume Body temperature less than 89.6ºF (32ºC) FIGURE 4-6 One type of commercially available heat and moisture High minute ventilation (≥ 10 L/min) exchanger. Patients on noninvasive ventilation with large mask leaks Courtesy of Smiths Medical. Patient receiving in-line aerosol drug treatments

Heat and Moisture Exchangers amount of humidity to achieve an isothermic Heat and moisture exchangers (HMEs), also referred saturation condition of 44 mg H2O/L (100% to as artificial noses, are simple, small, and passive humidity). The moisture output can decrease humidifiers. They are of three main types: (1) simple significantly as the minute volume increases, condenser, (2) hygroscopic condenser, or (3) hydro- 26 and usually HMEs are contraindicated when phobic condenser. All HMEs contain a condenser minute ventilation is ≥ 10 L/min. Trapping element with low thermal conductivity. The condens- water vapor on the condenser elements has ers are either impregnated with hygroscopic salt or the possibility of increasing the HME resistance composed of a water-repellent element (hydrophobic) causing increased work of breathing through the with large surface area for more efficient humidi- HME. This is seen mainly after prolonged used Figure 4-6 fication ( ). HMEs are typically used for of the HME (> 24–48 hours). Also the increase short-term ventilatory support and for humidification of the HME resistance as the water saturates during anesthesia. Whenever filtration capability is the condenser can lead to an ineffective low- added to these humidifiers, they are called heat and 27 pressure alarm during disconnection of the moisture exchangers/filters (HMEFs). The efficiency patient from the ventilator. HMEs remain the of the HMEs is quite variable, depending on the HME main source of mechanical dead space during design, tidal volume, patient’s characteristics, and 28 mechanical ventilation and can lead to increases atmospheric conditions. While in use, HMEs are in minute ventilation. Finally, unless calculated usually connected between the endotracheal tube and accounted for during mechanical ventilation, adaptor and the Y of the breathing circuit. A small HMEs can cause significant compressible volume corrugated tube approximately 10 cm long is usually loss that can lead to inaccurate effective tidal used to connect the HME to the endotracheal tube in volume delivery and reduction in the ventilator order to decrease the weight effect of the HME and performance. decrease the risk of endotracheal tube displacement. Principles of operation: Unless a heating element is As such, HMEs are the main source of mechanical added, HMEs do not actively add heat or water dead space during mechanical ventilation. All types vapor to the system.31 Exhaled heat and moisture of HMEs are for single patient use, and almost all of in expired gas during a breath are captured by them are fitted with a Luer port for measurement of the condenser element of the HME and on the the end tidal carbon dioxide tension. next inspiration, cool and dry inspired gas is Indications: HMEs are typically used for short-term warmed and humidified as it flows through the mechanical ventilation (< 72 hours), during patient condenser element of the HME. A good heat transport, and during anesthesia.29 and moisture exchanger should be at least 70% Contraindications: There are no contraindications efficient with humidity output ≥ 30 mg/L water to providing physiologic conditioning vapor, with standard connections, minimal dead of inspired medical gases and optimal space volume, and minimal flow resistance. humidification during mechanical ventilation. Currently available devices: HMEs are widely used in However, because of their nature, HMEs are critical care areas during mechanical ventilation contraindicated under some circumstances and in operating rooms during anesthesia. Most of (see Table 4-8). these devices have an additional filtration compo- Hazards: There are several hazards associated with nent aimed at protecting the patient from hospital- the use of HMEs.30 HMEs with low humidity acquired infections. Several commercial products outputs (< 25 mg/L) can result in hypothermia are available, and their general specifications and because the patient needs to add a significant characteristics are presented in Table 4-9.

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TABLE 4-9

Types and Specifications of Heat and Moisture Exchangers CHAPTER 4

Dead Product Recommended Space Name/ Tidal Volume Volume Weight

Manufacturer Number (ml) Moisture Output (mg H2O/L) Resistance in cm H2O Filtration Efficiency (mL) (g) Humidity andAerosol Therapy Flow VT = VT = VT = VT = VT = VT = VT = Flow = Flow = Flow = Flow = = 90 25 50 100 250 500 750 1000 Flow = 5 15 L/ 20 L/ 30 L/ 60 L/ L/ mL mL mL mL mL mL mL L/min min min min min min Bacterial Viral

ARC Medical, ThermoFlo 250–1500 N/A N/A N/A N/A 33 N/A 31 N/A N/A N/A 0.4 N/A N/A N/A N/A 75 32 Inc.

ThermoFlo 250–1500 N/A N/A N/A N/A 33 N/A 31 N/A N/A N/A 1.2 N/A N/A > 99.9% > 99.9% 75 33 Filter

ThermoFlo 250–1500 N/A N/A N/A N/A 32 N/A 30 N/A N/A N/A 1/2 N/A N/A > 99.9% > 99.9% 75 33 Filter S

ThermoFlo Midi 150–1200 N/A N/A N/A N/A 32 N/A 30 N/A N/A N/A 1.5 N/A N/A > 99.9% > 99.9% 47 29

Covidien DAR 300–1500 N/A N/A N/A 33.9 33.3 N/A 32.4 N/A N/A N/A 0.9 2.1 3.6 ≥ 99.999% 99.999% 90 50 352U5805

DAR 150–1200 N/A N/A N/A 34.4 33.6 N/A 32.9 N/A N/A N/A 1 2.8 4.7 ≥ 99.99% > 99.99% 51 28 352U5877

DAR 150–-1200 N/A N/A N/A 34.4 33.6 N/A 32.9 N/A N/A N/A 1.2 2.9 5.2 ≥ 99.99% > 99.99% 61 29 352U5996

DAR 300–1500 N/A N/A N/A 34.7 34.1 N/A 33.4 N/A N/A N/A 0.8 2.5 4.2 ≥ 99.999999% ≥ 99.999% 96 49 354U5876

DAR 200–1500 N/A N/A N/A 33 31.5 N/A 29.6 N/A N/A N/A 1.2 2.7 4.6 ≥ 99.999% ≥ 99.999% 66 36 354U19028

DAR 75–300 N/A N/A N/A 32.3 N/A N/A N/A N/A N/A 1.6 2.6 N/A N/A 99.999% > 99.99% 31 21 355U5430

DAR 30–100 N/A 30 N/A N/A N/A N/A N/A 0.6 N/A N/A N/A N/A N/A 99.999% > 99.99% 10 9 355U5427

Galemed HMEF 39012 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 99.99% 99.99% N/A N/A

HME Compact N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 99.99% 99.99% N/A N/A 3485

Smiths PORTEX 120–1500 N/A N/A N/A N/A 31 N/A N/A N/A 0.22 N/A N/A N/A N/A N/A N/A 42 21

26/09/14 5:13 PM Medical 002812 9781449601942_CH04_PASS02.indd 93

TABLE 4-9 Types and Specifications of Heat and Moisture Exchangers

Dead Product Recommended Space Name/ Tidal Volume Volume Weight

Manufacturer Number (ml) Moisture Output (mg H2O/L) Resistance in cm H2O Filtration Efficiency (mL) (g)

Flow VT = VT = VT = VT = VT = VT = VT = Flow = Flow = Flow = Flow = = 90 25 50 100 250 500 750 1000 Flow = 5 15 L/ 20 L/ 30 L/ 60 L/ L/ mL mL mL mL mL mL mL L/min min min min min min Bacterial Viral

Smiths PORTEX 900–1500 N/A N/A N/A 31 N/A N/A N/A N/A 1 N/A N/A N/A N/A N/A N/A 26 18 Medical 002813

PORTEX 400–1500 N/A N/A N/A N/A 30 N/A 27 N/A N/A N/A 1 3 5 N/A N/A 70 27 002814P

PORTEX >10 32 N/A N/A N/A N/A N/A N/A 0.9 N/A N/A N/A N/A N/A N/A N/A 3 3 002815

PORTEX 200–1500 N/A N/A N/A N/A 31 N/A N/A N/A N/A N/A 0.3 N/A N/A N/A N/A 66 30 002816

PORTEX 150–1500 N/A N/A N/A 31 N/A N/A N/A N/A N/A N/A N/A 1.8 N/A N/A N/A 31 27 002817P

PORTEX 90–1500 N/A N/A N/A 31 N/A N/A N/A N/A 0.1 N/A N/A N/A N/A N/A N/A 31 19 002818P

PORTEX 200–1500 N/A N/A N/A N/A 31 N/A N/A N/A N/A N/A 1 N/A N/A 99.9999% 99.9999% 66 31 002821

PORTEX 90–1500 N/A N/A N/A N/A 32 N/A N/A N/A N/A N/A 0.98 N/A N/A 99.9999% 99.9999% 76 38 002822

PORTEX 150–1500 N/A N/A N/A N/A 31 N/A N/A N/A N/A N/A 1.4 N/A N/A 99.9999% 99.9999% 55 40 002823P

PORTEX 90–1500 N/A N/A N/A 31 N/A N/A N/A N/A 1.1 N/A N/A N/A N/A 99.9999% 99.9999% 32 18 002825 Passive Humidifiers

PORTEX 400–1500 N/A N/A N/A N/A 31 N/A 28 N/A N/A N/A 1 2 4 N/A N/A 70 27 002841

PORTEX N/A N/A N/A N/A N/A 33 N/A 26 N/A N/A N/A 1 2.2 4 > 99.9% > 99.9% 103 52 002851P

PORTEX N/A N/A N/A N/A N/A 25 N/A 17 N/A N/A N/A 1 2.2 4 > 99.9% > 99.9% 32 20 002865 26/09/14 5:13 PM

(continues) 93 9781449601942_CH04_PASS02.indd 94 94

TABLE 4-9 Types and Specifications of Heat and Moisture Exchangers (Continued) CHAPTER 4

Dead Product Recommended Space Name/ Tidal Volume Volume Weight

Smiths PORTEX N/A N/A N/A N/A N/A 27 N/A 24 N/A N/A N/A 1 2.2 4 > 99.9% > 99.9% 67 46 Medical 002866

PORTEX N/A N/A N/A N/A N/A N/A N/A 25 N/A N/A N/A N/A 1.2 N/A N/A N/A 32 18.6 580021

Teleflex Gibeck 19912 250–1500 N/A N/A N/A N/A N/A N/A 30.4 N/A N/A N/A N/A 1.5 N/A N/A N/A 57 43

Gibeck 10011 15–50 30 N/A N/A N/A N/A N/A N/A N/A 1 N/A N/A N/A N/A N/A N/A 2.4 4.5

Gibeck 11112 50–600 N/A N/A N/A 30 N/A N/A N/A N/A N/A 0.3 N/A N/A N/A N/A N/A 14 11.6

Gibeck 13312 150–1500 N/A N/A N/A N/A 27 N/A N/A N/A N/A N/A N/A 0.8 N/A N/A N/A 29 20.9

Gibeck 17731 250–1500 N/A N/A N/A N/A 27 N/A N/A N/A N/A N/A N/A 0.8 N/A N/A N/A 54 26.4

Gibeck 11012 50–250 N/A N/A 30 N/A N/A N/A N/A N/A N/A 1.4 N/A N/A N/A N/A N/A 13 14.5

Gibeck 18502 150–1000 N/A N/A N/A N/A 30 N/A N/A N/A N/A N/A 2.1 N/A N/A N/A N/A 27 22

Gibeck 18402 150–1000 N/A N/A N/A N/A N/A N/A 30 N/A N/A N/A N/A 1.8 N/A N/A N/A 38 32.3

Gibeck 18832 250–1500 N/A N/A N/A N/A N/A N/A 31 N/A N/A N/A N/A 2 N/A N/A N/A 60 30

Vital Signs HMEF 1000 300–1000 N/A N/A N/A N/A 33 32 30 N/A N/A N/A 1 2.3 N/A 99.9999% 99.99% 77 24 (GE)

HMEF 750 120–750 N/A N/A N/A 32 30 27 N/A N/A N/A N/A 0.9 2.2 N/A 99.9999% 99.998% 34 17

HMEF 500 120–500 N/A N/A N/A 31 30 N/A N/A N/A N/A N/A 1.5 3.3 N/A 99.999% 99.98% 30 15

HMEF Mini 60–500 N/A N/A N/A 31 27 N/A N/A N/A N/A N/A 1.4 3.2 N/A 99.999% 99.98% 21 14

Westmed 6218 150–1000 N/A N/A N/A N/A 28.4 N/A N/A 0.48 N/A N/A 2.7 N/A N/A 99.99% 99.99% 21.3 N/A

6219 150–1000 N/A N/A N/A N/A 28.8 N/A N/A N/A N/A N/A 0.22 N/A N/A 19.7 N/A

6220 150–1000 N/A N/A N/A N/A 29.2 N/A N/A N/A N/A N/A 2.5 N/A N/A 99.99% 99.99% 19.7 N/A

6221 350–1500 N/A N/A N/A N/A 32.1 N/A N/A N/A N/A N/A 1.3 N/A N/A 99.99% 99.99% 69 N/A

6229 150–1000 N/A N/A N/A N/A 28.4 N/A N/A 0.35 N/A N/A N/A N/A N/A 21.3 N/A

26/09/14 5:13 PM 6379 350–1500 N/A N/A N/A N/A 32.1 N/A N/A N/A N/A N/A 1.3 N/A N/A 99.99% 99.99% 69 N/A References 95

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