CABT Patient Monitoring 3 — Questions and Answers
Question 1: A central venous pressure (CVP) waveform shows an elevated 'a' wave. This finding is most associated with:
- Tricuspid stenosis or right ventricular non-compliance (Correct answer)
- Tricuspid regurgitation
- Pulmonary hypertension
- Mitral stenosis
Correct answer: Tricuspid stenosis or right ventricular non-compliance
An elevated 'a' wave in the CVP tracing reflects increased atrial contraction force against a non-compliant or obstructed right ventricle, as seen in tricuspid stenosis.
Question 2: The bioimpedance method of cardiac output monitoring works by measuring changes in:
- Thoracic electrical impedance during cardiac cycles (Correct answer)
- Arterial blood temperature after cold saline injection
- CO2 elimination rate
- Oxygen saturation gradient across the lungs
Correct answer: Thoracic electrical impedance during cardiac cycles
Bioimpedance cardiac monitoring measures beat-to-beat changes in thoracic electrical resistance caused by blood flow, allowing non-invasive cardiac output estimation.
Question 3: Which alarm condition on a ventilator should a biomedical technician investigate first because it poses immediate life threat?
- Low pressure / disconnect alarm (Correct answer)
- High PEEP alarm
- FiO2 slightly above set value
- Tidal volume trending 5% low over 2 hours
Correct answer: Low pressure / disconnect alarm
A low pressure or disconnect alarm indicates the patient may not be receiving ventilatory support, representing an immediate life threat requiring urgent response.
Question 4: During ECG monitoring, a 60 Hz electrical interference pattern on the tracing is most likely caused by:
- Poor electrode contact or nearby electrical equipment (Correct answer)
- Patient movement
- Low battery in the monitor
- Incorrectly placed lead wires
Correct answer: Poor electrode contact or nearby electrical equipment
60 Hz interference (AC interference) is caused by nearby electrical equipment or poor skin-electrode contact allowing AC power line noise to couple into the signal.
Question 5: When a non-invasive blood pressure cuff is too large for the patient, what is the expected effect on the reading?
- Falsely low blood pressure reading (Correct answer)
- Falsely high blood pressure reading
- No effect on the reading
- Increased pulse pressure only
Correct answer: Falsely low blood pressure reading
An oversized cuff fails to generate adequate pressure over the artery, resulting in falsely low blood pressure measurements.
Question 6: Pulse transit time (PTT)-based blood pressure monitoring estimates blood pressure by measuring:
- The time delay between the ECG R-wave and the arrival of the pulse wave at a peripheral site (Correct answer)
- Stroke volume via aortic impedance
- Oxygen saturation at two different wavelengths
- Thermal dilution between two temperature sensors
Correct answer: The time delay between the ECG R-wave and the arrival of the pulse wave at a peripheral site
PTT-based monitoring measures the time for a pressure wave to travel from the heart to a peripheral sensor; shorter PTT correlates with higher blood pressure.
Question 7: A bispectral index (BIS) monitor primarily measures which physiological parameter?
- Depth of anesthesia or sedation via processed EEG (Correct answer)
- Cardiac output via echocardiography
- Cerebral perfusion pressure
- Degree of neuromuscular blockade
Correct answer: Depth of anesthesia or sedation via processed EEG
The BIS monitor uses a processed EEG algorithm to generate a numeric index (0–100) that reflects the patient's level of consciousness or depth of anesthesia.
CABT Patient Monitoring 3
A central venous pressure (CVP) waveform shows an elevated 'a' wave.
This finding is most associated with: