Unit 2: Primary Assessment
Respiration & Oxygenation
When a patient struggles to breathe, an EMT must quickly determine whether the patient is receiving enough oxygen and how serious the problem may be. Understanding respiration and oxygenation is essential for recognizing respiratory emergencies and making appropriate treatment decisions. This NREMT study guide lesson explains respiratory distress, abnormal breath sounds, pulse oximetry, and supplemental oxygen. Five EMT practice questions at the end will help you review these important concepts.
Breathing allows oxygen to enter the body and carbon dioxide to be removed. When this process is disrupted, vital organs may not receive the oxygen they need to function.
EMTs must assess the patient’s respiratory rate, breathing effort, breath sounds, and oxygen saturation to recognize problems before they become life-threatening.
Respiration, Ventilation, and Oxygenation
Although closely related, these terms describe different processes.
- Ventilation: The physical movement of air into and out of the lungs.
- Respiration: The exchange of oxygen and carbon dioxide between the lungs, blood, and body tissues.
- Oxygenation: The process of getting oxygen into the bloodstream.
Inside the lungs, oxygen moves from tiny air sacs called alveoli into surrounding capillaries. Carbon dioxide moves from the blood into the alveoli, where it is exhaled.
For effective gas exchange, air must reach the alveoli, and blood must circulate through the surrounding capillaries. This relationship is called ventilation-perfusion (V/Q) matching.
Conditions such as pneumonia, pulmonary edema, and pulmonary embolism can interfere with effective gas exchange.
Assessing Respiratory Status
EMTs assess several characteristics of a patient’s breathing.
Respiratory Rate
A normal resting respiratory rate for a healthy adult is approximately 12–20 breaths per minute. Normal rates vary with age, especially in children and infants.
Respiratory Depth
Determine whether breaths are deep enough to move adequate amounts of air. Shallow breathing may indicate inadequate ventilation even when the respiratory rate appears normal.
Respiratory Rhythm
Normal breathing is generally regular. Irregular breathing patterns may indicate a serious medical or neurological problem.
Breathing Effort
Observe whether the patient is breathing comfortably or struggling to move air.
Signs of increased breathing effort include:
- Use of accessory muscles in the neck or chest.
- Retractions between or below the ribs.
- Nasal flaring, particularly in children.
- Difficulty speaking in complete sentences.
- Sitting upright or leaning forward to breathe.
A complete respiratory assessment considers all these findings rather than relying on respiratory rate alone.
Respiratory Distress and Respiratory Failure
Respiratory distress occurs when a patient has difficulty breathing but is still making an effort to maintain adequate ventilation and oxygenation.
Common signs include rapid breathing, anxiety, wheezing, and increased work of breathing.
Respiratory failure occurs when the respiratory system can no longer maintain adequate oxygenation, ventilation, or both.
Warning signs include:
- Increasing fatigue and decreasing respiratory effort.
- Slow, shallow, or irregular breathing.
- Altered mental status.
- Poor air movement.
- Cyanosis, which is a bluish discoloration of the skin or mucous membranes.
A patient who initially breathes rapidly may develop slower, ineffective respirations as respiratory failure progresses.
Respiratory failure is a life-threatening condition that requires immediate intervention.
Abnormal Breath Sounds
Listening to lung sounds with a stethoscope helps EMTs identify possible respiratory problems.
Common abnormal breath sounds include:
- Wheezing: High-pitched, musical sounds caused by narrowed lower airways, commonly associated with asthma and COPD.
- Crackles (rales): Popping or crackling sounds that may indicate fluid or other material in the alveoli, as seen with pulmonary edema or pneumonia.
- Rhonchi: Low-pitched, coarse sounds associated with secretions in larger airways.
- Stridor: A harsh, high-pitched sound usually heard during inspiration, suggesting upper airway narrowing or obstruction.
- Diminished or absent breath sounds: May indicate severely reduced airflow, an obstruction, or another serious respiratory condition.
Breath sounds provide important clues, but they do not establish a diagnosis by themselves.
Pulse Oximetry
A pulse oximeter is a device that estimates the percentage of hemoglobin carrying oxygen in the bloodstream. This measurement is called peripheral oxygen saturation (SpO₂).
For most healthy adults at sea level, normal oxygen saturation is approximately 95–100%.
Pulse oximetry is useful for identifying low oxygen levels and monitoring a patient’s response to treatment.
However, readings can be affected by:
- Poor circulation or cold extremities.
- Patient movement.
- Nail polish or artificial nails.
- Differences in skin pigmentation.
- Certain medical conditions and environmental factors.
A conventional pulse oximeter may also display a falsely reassuring reading in patients with carbon monoxide poisoning.
Never rely on pulse oximetry alone. A patient with a normal SpO₂ reading may still have inadequate ventilation or a serious respiratory emergency.
Supplemental Oxygen
Supplemental oxygen helps increase the amount of oxygen available to patients who are not adequately oxygenated.
Two common oxygen-delivery devices are:
Nasal Cannula
A nasal cannula delivers oxygen through two small prongs placed in the nostrils.
- Typical flow rate: 1–6 liters per minute (L/min).
- Provides relatively low concentrations of supplemental oxygen.
- Commonly used for spontaneously breathing patients who need additional oxygen.
Nonrebreather Mask
A nonrebreather mask covers the nose and mouth and includes an oxygen reservoir bag.
- Typical flow rate: 10–15 L/min, adjusted to keep the reservoir adequately inflated.
- Delivers a higher concentration of oxygen than a nasal cannula.
- Used when a spontaneously breathing patient requires high-concentration supplemental oxygen.
Neither device provides adequate ventilation for a patient who is not breathing effectively. Such patients may require assisted ventilation with a bag-valve-mask (BVM), which is covered in the next lesson.
Administering Oxygen Safely
Oxygen should be administered according to the patient’s clinical condition, oxygen saturation, and local EMS protocols.
For many acutely ill adults, a common target oxygen saturation is 94–98%. Patients at risk of retaining carbon dioxide, such as some patients with COPD, may require a lower target, often 88–92%.
EMTs should not automatically withhold oxygen from a patient with COPD who has severe hypoxemia or another immediately life-threatening condition.
Reassess the patient’s breathing, mental status, and oxygen saturation after treatment. Avoid giving unnecessarily high concentrations of oxygen when the patient is already adequately oxygenated.
Key Tip
A normal oxygen saturation reading does not guarantee that a patient is breathing adequately. Always evaluate respiratory rate, depth, effort, mental status, and breath sounds. If the patient is breathing inadequately, assisted ventilation may be more important than simply increasing supplemental oxygen.