Anatomy, Physiology, and Clinical Applications
Anatomy, Physiology, and Clinical Applications
This domain tests organ systems, vital signs, common clinical measurements, and how device readings correlate with physiology.
Core rules
- Cardiovascular: ECG reflects electrical activity; BP = cardiac output × systemic vascular resistance; pulse oximetry uses red and infrared absorption.
- Respiratory: ventilation and oxygenation are different; capnography measures CO2, while pulse oximetry does not measure ventilation.
- Renal: dialysis depends on access, blood flow, and dialysate conductivity and temperature.
- Neuro: EEG amplitude and frequency are interpreted with artifact from muscle and movement in mind.
Worked example
A patient has SpO2 88%, normal capnography, and clear lungs. Low SpO2 suggests an oxygenation problem or poor perfusion or artifact. Check probe placement, perfusion, hemoglobin, and motion; do not assume hypoventilation from SpO2 alone.
Traps
- Treating SpO2 as a ventilation measure.
- Using the wrong BP cuff size.
- Ignoring motion artifact in pulse oximetry and ECG.