CABT Patient Monitoring 4 — Questions and Answers
Question 1: During pulmonary artery catheter insertion, the characteristic waveform that confirms the catheter tip is in the right ventricle is:
- High systolic pressure with low diastolic pressure and no dicrotic notch (Correct answer)
- Low phasic waveform with prominent 'a' and 'v' waves
- Continuous low-pressure waveform
- High systolic and diastolic pressure with dicrotic notch
Correct answer: High systolic pressure with low diastolic pressure and no dicrotic notch
The right ventricular waveform shows high systolic pressure, near-zero diastolic pressure, and a distinct upstroke without a dicrotic notch, differentiating it from the pulmonary artery.
Question 2: A near-infrared spectroscopy (NIRS) oximeter placed on the forehead primarily monitors:
- Regional cerebral oxygen saturation (rSO2) (Correct answer)
- Systemic arterial oxygen saturation
- Mixed venous oxygen saturation
- Tissue CO2 partial pressure
Correct answer: Regional cerebral oxygen saturation (rSO2)
NIRS cerebral oximeters use near-infrared light to measure the regional oxygen saturation of the underlying brain tissue in a non-pulsatile manner.
Question 3: When calibrating a pressure transducer to atmospheric pressure, the biomedical technician should confirm the displayed pressure reads:
- 0 mmHg (Correct answer)
- 760 mmHg
- 101.3 kPa
- 14.7 psi
Correct answer: 0 mmHg
After zeroing to atmospheric pressure, the monitor should display 0 mmHg, as gauge pressure is measured relative to ambient atmospheric pressure.
Question 4: In ECG monitoring, which lead is best for detecting P-waves and identifying atrial arrhythmias?
- Lead II (Correct answer)
- Lead aVR
- Lead V6
- Lead I
Correct answer: Lead II
Lead II runs parallel to the mean atrial electrical axis, producing tall, upright P-waves that are easiest to identify for arrhythmia analysis.
Question 5: A sudden loss of the capnography waveform (flat line) in an intubated patient most urgently suggests:
- Esophageal intubation or circuit disconnection (Correct answer)
- Mild hyperventilation
- Sedation that is too deep
- Normal breathing pattern
Correct answer: Esophageal intubation or circuit disconnection
Loss of the capnography waveform in an intubated patient indicates no CO2 is being detected, which can signal esophageal intubation or a disconnected ventilator circuit.
Question 6: Which safety standard governs the maximum allowable leakage current for patient-applied monitoring equipment in the US?
- ANSI/AAMI ES60601-1 (Correct answer)
- IEC 61000
- NFPA 70 (NEC)
- UL 508A
Correct answer: ANSI/AAMI ES60601-1
ANSI/AAMI ES60601-1 (based on IEC 60601-1) sets the safety requirements including leakage current limits for medical electrical equipment applied to patients.
Question 7: Overdamping of an invasive arterial pressure waveform will result in:
- Underestimation of systolic pressure and overestimation of diastolic pressure (Correct answer)
- Overestimation of systolic pressure and underestimation of diastolic pressure
- Accurate mean arterial pressure only if correctly zeroed
- No effect on numeric values
Correct answer: Underestimation of systolic pressure and overestimation of diastolic pressure
An overdamped waveform smooths out pressure oscillations, reducing the measured systolic peak and raising the apparent diastolic value, while mean pressure remains relatively accurate.
CABT Patient Monitoring 4
During pulmonary artery catheter insertion, the characteristic waveform that confirms the catheter tip is in the right ventricle is: