CBET Medical Equipment Function 4

Question 1

In a pulse oximeter, which physiological principle is used to differentiate oxygenated from deoxygenated hemoglobin?

Accepted Answer

Differential light absorption at two wavelengths (660 nm and 940 nm)

Answer

Measurement of blood pressure waveform morphology

Answer

Detection of CO2 partial pressure via infrared spectroscopy

Answer

Impedance plethysmography across the finger

Question 2

A patient-controlled analgesia (PCA) pump must include which safety feature to prevent accidental overdose?

Accepted Answer

A lockout interval that disables bolus delivery for a set time after each dose

Answer

A variable drip rate adjusted by nursing staff every hour

Answer

An automatic increase in dose when the patient presses the button repeatedly

Answer

A pressure sensor that detects IV line occlusion only

Question 3

What is the primary function of the inspiratory-to-expiratory (I:E) ratio setting on a mechanical ventilator?

Accepted Answer

It controls the proportion of time spent in inhalation versus exhalation during each breath cycle

Answer

It sets the tidal volume delivered with each breath

Answer

It determines the oxygen concentration in delivered gas

Answer

It adjusts the peak airway pressure alarm threshold

Question 4

In electrosurgical units (ESU), the return electrode (dispersive pad) functions by:

Accepted Answer

Distributing current over a large surface area to minimize current density at the patient return site

Answer

Increasing the frequency of current to improve cutting precision

Answer

Grounding the patient to earth to prevent shock

Answer

Concentrating current to coagulate tissue at the return site

Question 5

A phototherapy unit used for neonatal jaundice delivers light primarily in which spectral range?

Accepted Answer

Blue-green light (420–500 nm)

Answer

Red light (620–700 nm)

Answer

Ultraviolet-C (200–280 nm)

Answer

Near-infrared (750–900 nm)

Question 6

Which mechanism allows a double-lumen endobronchial tube to facilitate one-lung ventilation during thoracic surgery?

Accepted Answer

Separate lumens allow one lung to be isolated and collapsed while the other is ventilated

Answer

It delivers 100% oxygen to both lungs simultaneously at high flow

Answer

A balloon in the trachea seals off the airway above the carina

Answer

It uses CPAP on one side and PEEP on the other to equalize pressures

Question 7

In a hemodialysis machine, the dialysate flow direction relative to blood flow is typically:

Accepted Answer

Countercurrent, to maximize the concentration gradient for diffusion across the dialyzer membrane

Answer

Co-current, to prevent pressure differentials across the membrane

Answer

Perpendicular, to promote ultrafiltration only

Answer

Intermittent, alternating direction every five minutes