Anatomy and Physiology Review
- The upper and lower airway
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- The muscles of respiration
Pathophysiology
- True respiratory disorders
- Chronic obstructive pulmonary disease (COPD) is most commonly either emphysema (breakdown of the alveoli) or chronic bronchitis (inflammation of the bronchial passageways and frequent infections), or both.
- Asthma is a chronic disease that features occasional “attacks.” It is characterized by inflammation of the bronchial passageways, increased mucus production and occasional spasm of the bronchial tubes (the mechanism that causes the attack).
- Acute pulmonary edema (APE) occurs when fluid occupies space in or around the alveoli. It is most commonly caused by congestive heart failure, specifically, when the left side of the heart does not pump efficiently and causes a pressure backup into the lungs. APE can also be caused by drowning, high altitude and toxic inhalations.
- A pulmonary embolism is a clot in the blood vessels that return blood to the lungs. A massive pulmonary embolism can block blood from a large section of the lung and cease all gas exchange in that area.
- A pneumothorax occurs when air enters the pleural space between the chest wall and the lung. If the air is sufficient in quantity, it can collapse the lung. If pressure becomes excessive, the heart and great vessels can be displaced causing a life-threatening tension pneumothorax. This condition is most commonly caused by trauma but can also occur from medical causes (spontaneous pneumothorax).
- Infections
- Pneumonia is an infection that occurs in the lung tissue and affects the lungs’ ability to exchange gas.
- Epiglottitis is an infection that occurs most commonly in the upper airway. It can cause swelling of the tissues of the larynx and impede breathing.
- Bronchiolitis is not a specific disorder but a classification for several infections that cause inflammation in the lower airways. These infections, such as respiratory syncytial virus, occur most commonly in children less than 3 years of age and can cause life-threatening respiratory insufficiency.
- Other respiratory infections such as influenza can cause upper and lower respiratory infections. Although not as commonly life threatening as some of the other pathophysiologies discussed here, they can be dangerous and are often highly contagious.
- Cystic fibrosis is not an infection but a genetic condition that causes, among other things, the production of thick, sticky mucus. This mucus frequently traps microbes and makes it more difficult for the body to expel these foreign invaders. As a result, respiratory infections are common and are a frequent cause of death among people who have this condition.
- Other
- Acute myocardial infarction can cause the sensation of dyspnea and can be linked to acute pulmonary edema. Although this is not a true “respiratory” pathology, practitioners should identify shortness of breath as a common indication of cardiac problems.
- Shock and compensation for shock can cause the sensation of dyspnea. Shock should be suspected in any patient with tachypnea.
Signs and Symptoms
- Dyspnea: The sensation of shortness of breath that is reported to you by the patient.
- Respiratory distress: Increased work of breathing that is observable. Findings that are associated with respiratory distress include:
- unusual patient positioning, such as the tripod position.
- accessory muscle use, such as retractions of the clavicular, neck and intercostal muscles. Abdominal breathing (seesaw breathing) would also be considered here.
- nasal flaring, pursed lip breathing and air gulping.
- Signs of hypoxia, including altered mental status, cyanosis and decreased oxygen saturation readings.
- Unusual sounds of breathing (either audible or as auscultated with a stethoscope) including stridor, hoarse voice, wheezing, rales and/or rhonchi. Consider grunting with each breath an ominous sign as well.
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Treatment
- If breathing is inadequate, positive pressure ventilation is necessary. Use a pocket mask or bag mask device to breathe for the patient.
- Treat hypoxic patients who are breathing adequately with supplemental oxygen. Use delivery devices such as a nasal cannula or nonrebreather mask, and titrate oxygen delivery to 94–95% saturation.
- Consider the need for advanced life support.
- Patients with bronchoconstriction can be treated with inhaled bronchodilators. Consider assisting patients with the use of their metered dose inhaler or small volume nebulizer. Note that some protocols allow EMTs to carry and administer these drugs. Always consult your local protocols.
- Continuous positive airway pressure (CPAP) can be used to treat patients with acute pulmonary edema and, in some cases, those with bronchoconstriction. Follow local protocol.
Important Concepts
- The most important decision to be made with any respiratory distress patient is whether he or she is breathing adequately or inadequately. Inadequate breathing requires IMMEDIATE intervention. Signs of inadequate breathing include:
- altered mental status.
- persistent cyanosis (especially after supplemental oxygen).
- slowing or irregular breathing (patients will occasionally describe respiratory fatigue).
- inability to speak (the number of words a patient can speak without pausing to take a breath is thought to be an accurate indicator of the severity of respiratory distress).
- poor air movement as evidenced by a silent chest.
- A thorough assessment of a respiratory distress patient is essential. Patient assessment will not only identify the patient who is breathing inadequately but also will commonly define the best course of action for treatment.
- In particular, patient history will play an essential role in creating a working diagnosis (even if you will not be making the diagnosis, the information you obtain will still be important). Use SAMPLE as a guide, but consider specifically:
- how long the episode of respiratory distress has been going on. Some disorders have an acute onset (as with acute pulmonary edema or spontaneous pneumothorax), whereas other disorders are chronic in onset (as with exacerbation of COPD or pneumonia). Onset is often a key to reaching a correct diagnosis.
- past medical history. Most commonly, today’s episode is linked to yesterday’s problem—for example, a patient who has a history of asthma is most likely having an asthma attack (although other causes certainly are possible).
- This memory aid will help you better understand severity and other mitigating factors.
- Don’t forget the technology of assessment. Use pulse oximeters to confirm oxygenation. Auscultate lung sounds with a stethoscope. Use capnography if your protocol allows.