The Primary Components Of The Respiratory System Are Like An Inverted Tree, With The Trachea Representing The Tree’S Trunk And The Alveoli Resembling The Tree’S Leaves.

 The primary components of the respiratory system are like an inverted tree, with the trachea representing the tree’s trunk and the alveoli resembling the tree’s leaves.  The mouth and oropharynx are very vascular and are covered by a mucous blanket. Swelling can be profound and potentially dangerous.  The larynx and glottis are typically considered the dividing line between the upper airway and the lower airway. The thyroid cartilage is the most obvious external landmark of the larynx. The glottis and vocal cords are found in the middle of the thyroid cartilage.  The cricoid cartilage can be palpated just below the thyroid cartilage in the neck. It forms a complete ring and maintains the trachea in an open position. Applying cricoid pressure or Sellick maneuver may be helpful with intubation.  The small space between the thyroid and cricoid cartilages is the cricothyroid membrane. It is a good choice for inserting a large IV catheter or a small breathing tube.  Cilia line the larger airways and help move foreign material out of the tracheobronchial tree. If a patient is dehydrated or has taken medications that dry secretions (such as antihistamines), the cilia will not be able to effectively move secretions. The same is true if the patient is overhydrated.  Pulmonary circulation begins at the right ventricle, where the pulmonary artery branches into increasingly smaller vessels until it reaches the pulmonary capillary bed, which surrounds the alveoli and terminal bronchioles.  Patients who have traumatic brain injuries may exhibit bizarre respiratory patterns, including agonal gasps; apneustic and ataxic patterns; and Biot, Cheyne- Stokes, and Kussmaul respirations; as well as central neurogenic hyperventilation, bradypnea, hyperpnea, hypopnea, and tachypnea.  The respiratory system delivers oxygen to the body and removes the primary waste product of metabolism, carbon dioxide. If the lungs are not functioning appropriately, both of these vital functions may be impaired. Hypoxia, cell death, and acidosis can then occur.  The brain is very sensitive to reduced levels of oxygen. It requires a regular supply of both oxygen and glucose to function, but can store neither. Alteration in level of consciousness could represent respiratory compromise.  A patient who has respiratory disease may not be able to talk because he or she is having difficulty breathing. You may have to obtain the history from a family member or from only a few clues.  It is critical to evaluate how hard your patient is working to breathe. Patients in respiratory distress may be able to compensate at first, but will eventually become sleepy, have a decreased respiratory rate and depth, and then, decompensate.  Patients who have chronic respiratory disease are often knowledgeable about their disease and may have tried several potential treatment options already. Ask them about these efforts and what results, if any, they produced.  Onset and duration of distress are important considerations in determining the underlying cause. Find out if the problem happened suddenly or gradually worsened over time.  Assessing the patient’s position of comfort and difficulty speaking may help you gauge the patient’s degree of distress. A patient sitting in a Fowler’s position and speaking only in two- or three-word statements is probably in considerable distress.  Patients in respiratory distress tend to seek the tripod position. The condition of a patient in respiratory distress who is willing to lay flat may be quickly deteriorating. Head bobbing is also an ominous sign.  Find out if the patient’s condition is a recurrence of a past condition. If so, compare the current situation with other episodes.  Note any audible abnormal respiratory noises. Noisy breathing is obstructed breathing.  Snoring indicates partial obstruction of the upper airway by the tongue. Stridor indicates narrowing of the upper airway, usually as a result of swelling (laryngeal edema).  Assessing the level of consciousness is enormously important in dyspneic patients.  Assess the patient’s mucous membranes for cyanosis (a bluish or dusky color), pallor, and moisture.  Look for jugular venous distention in the neck, with the patient in a semi-sitting position. Distended neck veins may be caused by cardiac failure.  Feel the chest for vibrations as the patient breathes. Check for edema of the ankles or lower back. Check for peripheral cyanosis. Check the pulse and note the patient’s skin temperature. Attach any available monitors.  Auscultate the lungs whenever possible. Adventitious breath sounds are the extra noises that you may hear; they include wheezing or crackles.  Crackles are any discontinuous noises heard on auscultation of the lungs. They are caused by the popping open of air spaces and are usually associated with increased fluid in the lungs.  Wheezes are high-pitched, whistling sounds made by air being forced through narrowed airways, which makes them vibrate. Wheezing may be diffuse in conditions such as asthma and congestive heart failure or localized when caused by a foreign body obstructing a bronchus.  Silence means danger! If you don’t hear anything with your stethoscope, the patient is not moving enough air to ventilate the lungs.  Note whether the patient is coughing up colorful sputum, if the color or amount of sputum has changed, and if it contains blood or pus.  A pulse oximeter indicates what percentage of the patient’s hemoglobin has oxygen attached to it. An oxygen saturation level greater than 95% is considered normal.  The peak flow is the maximum flow rate at which the patient can expel air from the lungs. Normal peak flows run from about 350 to 700 L/min. A peak flow of less than 150 L/min is very low and signals significant distress.  A variety of infections can cause swelling in the upper airway. Croup is one of the most common, though it usually occurs only in small children.  Pulmonary aspiration of stomach contents is very dangerous. Avoid causing gastric distention when bagging the patient, and monitor the patient’s ability to protect his or her airway. If you determine that the patient can’t protect his or her airway, one of your primary jobs is to protect it for them, and that means intubation.  Common obstructive airway diseases include emphysema, chronic bronchitis, and asthma. Emphysema and chronic bronchitis are collectively classified as COPD.  Asthma is caused by allergens or irritants and is characterized by widespread, reversible narrowing of the airways (bronchospasm), edema of the airways, and increased mucous production. It can cause significant airway obstruction.  Primary treatment of bronchospasm is bronchodilator medication. Primary treatment of bronchial edema is corticosteroids, which may or may not be administered in the field setting.  Status asthmaticus is a severe, prolonged asthmatic attack that cannot be broken with conventional treatment. It is a dire medical emergency. Any person with asthma who feels sick enough to call an ambulance is in status asthmaticus until proved otherwise.  When a patient has recurring asthma attacks, his or her inhaler could be empty or the medication could no longer be effective. Try administering a new bronchodilator.  Emphysema is a chronic weakening and destruction of the walls of the terminal bronchioles and alveoli. A patient with emphysema classically has a barrel chest, muscle wasting, and pursed-lip breathing. Such patients are often tachypneic.  Chronic bronchitis is characterized by excessive mucous production in the bronchial tree, nearly always accompanied by a chronic or recurrent productive cough. A patient with chronic bronchitis tends to be sedentary and obese, sleep in an upright position, use many tissues, have copious secretions, and be cyanotic.  In assessing patients who have COPD, search for what pushed them over the edge. Look for signs of infection, peripheral edema, jugular venous distention with hepatojugular reflux, and crackles. Find out if the onset of dyspnea was sudden or gradual.  Not everyone should be ventilated the same way. Allow each breath to come back out before the delivery of the next breath. If you don’t, pressures in the thorax will rise, eventually causing pneumothorax or cardiac arrest. Patients with severe obstructive diseases should be ventilated as little as 4 to 6 breaths/min.  Noncompliance could trigger an asthma attack. Ask what the patient was doing when the asthma attack began. Ask if the patient took his or her medications today. Ask if movement worsens the dyspnea.  Pneumonia may be caused by a variety of bacterial, viral, and fungal agents. The patient with pneumonia usually reports weakness, productive cough, fever, and sometimes chest pain that worsens with coughing. Supportive care includes oxygenation, suctioning, and transport to an appropriate facility.  Pulmonary edema occurs when fluid migrates into the lungs. The patient expectorating pink and foamy secretions probably has severe pulmonary edema.  When a patient has a pneumothorax, air collects between the visceral pleura and the parietal pleura. Administer supplemental oxygen and monitor the patient’s respiratory status closely.  Pleural effusion will make the patient dyspneic. Supportive care, including proper positioning and aggressive oxygen administration, should be given.  A pulmonary embolism occurs when a blood clot breaks off in the circulation and travels to the lungs, blocking blood flow and nutrient exchange. Bedridden patients and people with thrombophlebitis are at risk of pulmonary embolism. The hallmark of pulmonary embolus is cyanosis that does not resolve with oxygen therapy.  Respiratory failure, or insufficient ventilation, can occur from a multitude of pathologic conditions, from injuries to the lungs, heart, and neurologic system to overdoses. Care includes providing supplemental oxygen.  In hyperventilation syndrome, ventilation is excessive. If it continues, the patient may experience chest pain and carpopedal spasm. Psychological support techniques such as counting breaths, and distraction work best and help calm the patient.  In managing the condition of a patient who is in respiratory distress, begin by ensuring that there is an open and maintainable airway. Suction if necessary and keep the airway optimally positioned. Remove constricting clothing. Reduce the patient’s effort to breathe.  Patients in respiratory failure may ultimately need to be intubated. There are major drawbacks and risks to intubating in the field, but it can also be lifesaving. Weigh these issues along with protocols, medical direction, and the patient’s wishes.  Metered-dose inhalers deliver medication as an aerosol treatment. They are usually the delivery method of choice for both bronchodilators and corticosteroids in the home setting. Improper technique may result in little or no medication actually getting into the lungs.  Aerosol nebulizers deliver liquid medications in the form of a fine mist to the respiratory tract. Weigh the potential benefits of aerosol therapy against the lower FIO2 delivered during the treatment.  Drug administration methods that require the patient to inhale the medication may become unreliable or ineffective when the patient’s airways are severely compromised. Some cases may warrant delivering medications subcutaneously instead.  Medications can be instilled directly into the tracheobronchial tree when patients are intubated or have a tracheotomy. Stop CPR compressions for a moment when you instill the medication.  Continuous positive airway pressure (CPAP) is used as therapy for respiratory failure. Within several minutes of application, the patient’s oxygen saturation should increase, and the respiratory rate should decrease.  Bilevel positive airway pressure (BiPAP) is CPAP that delivers one pressure during inspiration and a different pressure during exhalation. It is more like normal breathing and is often more comfortable for the patient.  Automated transport ventilators are essentially flow-restricted oxygen-powered breathing devices with timers on them. They are particularly good choices for filling the role of the bag-mask ventilator when the patient is in cardiac or respiratory arrest, but are not intended to ventilate patients without direct observation and attention from a skilled practitioner.