Want to test your physiology knowledge before the CTRN exam? Below are free sample flashcards from the 40-card physiology section of our 1050-card CTRN (Certified Transport Registered Nurse) deck, which covers Cardiac Index, BAC, Blood Alcohol Concentration and more.
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During transport of an intubated patient, you climb to 8,000 ft. You notice the ETT cuff pressure has increased from 25 to 35 cmH2O. Which gas law explains this, and what is the immediate intervention?
Show answer →Boyle's Law (P1V1 = P2V2). As barometric pressure decreases during ascent, the volume of gas in enclosed spaces (like an ETT cuff) expands. Intervention: Monitor cuff pressures frequently with a manometer. Unchecked expansion can cause tracheal ischemia/necrosis. BCEN Tip: Boyle's is the most frequently tested law regarding air-filled bubbles, cuffs, and organs. Remember: Boyle's = Bubbles/Balloons.
A patient with a recent penetrating eye injury and suspected intraocular air requires transport. Why is aeromedical transport a relative contraindication, and what is the priority?
Show answer →Boyle's Law. Intraocular air (even a tiny bubble) will expand during ascent. Because the eye is a non-distensible globe, this expansion causes a rapid, dangerous increase in intraocular pressure (IOP), which can lead to permanent blindness or extrusion of intraocular contents. Priority: Transport via ground if possible. If air transport is mandatory, maintain a Sea Level cabin altitude or fly at the lowest possible altitude.
A patient in cardiogenic shock with a Cardiac Index of 1.2 L/min/m2 is experiencing tissue hypoxia despite normal hemoglobin and adequate PaO2. Identify this specific hypoxia type and its mechanism.
Show answer →Stagnant Hypoxia. This is caused by a failure of the circulatory system to move oxygenated blood to the tissues. Despite the blood having enough O2 (unlike hypoxic hypoxia) and enough hemoglobin (unlike hypemic hypoxia), the pump or pipes fail. Causes: Heart failure, shock, pulmonary embolism, or excessive G-forces (G-LOC). Clinical Pearl: In transport, stagnant hypoxia can also be localized—such as in a limb with a compartment syndrome or an arterial occlusion. Treatment focuses on improving cardiac output and perfusion pressure.
According to safety standards in transport nursing, being awake for 17 consecutive hours results in cognitive impairment equivalent to what Blood Alcohol Concentration (BAC)?
Show answer →17 hours of wakefulness is equivalent to a BAC of 0.05%. Extending this to 24 hours of wakefulness is equivalent to a BAC of 0.10% (legally intoxicated in all US states). This level of fatigue severely impairs hand-eye coordination, decision-making, and communication. Exam Tip: BCEN prioritizes Safety and Professional Issues. Expect questions linking fatigue to medical errors. Strategies to mitigate this include strategic napping (20-40 mins) and recognizing circadian troughs (0200-0600) when error risk is highest.
Which gravitational axis is most tolerated by humans during transport, and why is this relevant for patient positioning?
Show answer →Gx (transverse/anterior-posterior) is the best tolerated axis because the heart and brain remain on the same horizontal plane, minimizing the hydrostatic pressure gradient changes seen in Gz. This is why patients are typically transported in a supine/flat position in fixed-wing aircraft to minimize vertical G-load during acceleration and deceleration.
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Try 30 free CTRN cards firstThe full CTRN deck contains 1050 flashcards, and 40 of them focus on physiology. This page shows 5 free samples.
Our CTRN deck dedicates 40 of 1050 cards (4%) to physiology — always cross-check the official BCEN exam outline for the current blueprint weighting.
Yes — the samples on this page are free, and the CTRN preview page has 30 more free cards. Full access to all 1050 cards is a one-time $7.
Assessment
30 cards
Basics
60 cards
Diagnostics
40 cards
Management
250 cards
Pathology
350 cards
Pharmacology
90 cards
Procedures
150 cards
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