Paramedic Exam

This chapter covers how to recognize respiratory distress and failure, how to interpret lung sounds, and the strengths and limits of pulse oximetry and waveform capnography. The exam often hands you these findings in words and asks which one matters most.

Respiratory distress means increased work of breathing with adequate gas exchange: tachypnea, accessory muscle use, retractions (suprasternal, intercostal, subcostal), nasal flaring, tripod positioning, and speaking in short phrases. Respiratory failure means the effort is no longer enough: altered mental status (anxiety, then confusion, then somnolence), cyanosis, falling SpO2 despite oxygen, rising ETCO2, bradypnea, shallow breaths, and, in children, head bobbing and see-saw (paradoxical) breathing. Respiratory arrest is the absence of effective breathing.

Exam Tip: The single most important sign of impending respiratory failure is a change in mental status. A wheezing asthmatic who stops fighting and becomes quiet and drowsy is not improving; they are tiring out. The best answer is to begin assisting ventilations.

Abnormal Breath Sounds

Common Trap: Wheezing in an older patient with orthopnea, jugular vein distention, edema and crackles may be "cardiac asthma" from pulmonary edema. A history of heart failure and hypertension steers you to CPAP and nitroglycerin rather than to bronchodilators alone.

Pulse oximetry estimates the percentage of hemoglobin saturated with oxygen. Target SpO2 is generally 94-99% for most patients, 88-92% for known chronic CO2 retainers, 92-98% after return of spontaneous circulation, and 94% (oxygen only when SpO2 is under 90%) in acute coronary syndrome.

Pulse Oximetry Pitfalls

Pulse oximetry tells you nothing about ventilation and lags behind real events. Treat the patient, not the number: a cyanotic, gasping patient with an SpO2 of 96% on a cold finger needs airway support.

Capnography measures exhaled CO2. Normal ETCO2 is 35-45 mmHg. A normal capnogram has a square-box shape: phase I (baseline, dead space gas with zero CO2), phase II (a sharp upstroke as alveolar gas arrives), phase III (the alveolar plateau, ending at the ETCO2 value), and phase 0 (a sharp downstroke as inspiration begins).

Capnography Waveform Patterns

Waveform capnography is required to confirm endotracheal tube placement and to monitor it continuously. A persistent waveform over six or more breaths confirms tracheal placement better than any other single field method. Lung sounds, chest rise, tube fogging and colorimetric devices are supporting signs only.

Exam Tip: If a question describes a sudden drop of the waveform to a flat line in an intubated patient who still has a pulse, the most likely cause is tube displacement or disconnection. If the ETCO2 falls gradually during a long transport while the patient remains intubated and ventilated, think of falling cardiac output.

Field Scenario: At 0340 you are called to a 34-year-old found unresponsive in a bathroom with a syringe nearby. Respirations are 4/min and shallow, SpO2 is 89% on room air, and nasal capnography shows a tall, slow waveform at 72 mmHg. The paramedic should open the airway, ventilate with a BVM and oxygen at 10-12 breaths/min, then titrate naloxone to adequate respirations rather than to full consciousness. The high ETCO2 confirms hypoventilation; a falling ETCO2 toward the 40s with each breath confirms that ventilation is working.

In children, use the pediatric assessment triangle (appearance, work of breathing, circulation to skin) from the doorway. Grunting is an attempt to create PEEP and signals significant lower airway disease. Bradycardia in a hypoxic child is a pre-arrest sign. In older adults, confusion may be the only sign of hypoxia or hypercapnia.

Altered mental status is the key sign that distress has become respiratory failure.

Pulse oximetry misses carbon monoxide, reads near 85% in methemoglobinemia, and lags behind real events.

Normal ETCO2 is 35-45 mmHg; shark fin means bronchospasm, sudden loss means displacement or disconnection.

Waveform capnography is the standard to confirm and continuously monitor tube placement.

Grunting, head bobbing and bradycardia in a child are ominous.