Medical Equipment Function Flashcards
7 cards from real CBET practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Medical Equipment Function flashcards as text
In a pulse oximeter, which physiological principle is used to differentiate oxygenated from deoxygenated hemoglobin?
Answer: Differential light absorption at two wavelengths (660 nm and 940 nm)
Pulse oximeters exploit the fact that oxyhemoglobin and deoxyhemoglobin absorb red (660 nm) and infrared (940 nm) light at different ratios.
A patient-controlled analgesia (PCA) pump must include which safety feature to prevent accidental overdose?
Answer: A lockout interval that disables bolus delivery for a set time after each dose
The lockout interval enforces a mandatory waiting period between boluses, preventing the patient from receiving dangerous cumulative doses.
What is the primary function of the inspiratory-to-expiratory (I:E) ratio setting on a mechanical ventilator?
Answer: It controls the proportion of time spent in inhalation versus exhalation during each breath cycle
The I:E ratio defines how the breath cycle is divided, affecting gas distribution and hemodynamic impact; normal is approximately 1:2.
In electrosurgical units (ESU), the return electrode (dispersive pad) functions by:
Answer: Distributing current over a large surface area to minimize current density at the patient return site
The large area of the dispersive pad spreads current so densely is too low to heat tissue, preventing burns at the return site.
A phototherapy unit used for neonatal jaundice delivers light primarily in which spectral range?
Answer: Blue-green light (420–500 nm)
Blue-green light in the 420–500 nm range is absorbed by bilirubin, converting it to water-soluble isomers that can be excreted.
Which mechanism allows a double-lumen endobronchial tube to facilitate one-lung ventilation during thoracic surgery?
Answer: Separate lumens allow one lung to be isolated and collapsed while the other is ventilated
Each lumen opens to one bronchus; clamping one lumen collapses that lung for surgical access while the other continues ventilation.
In a hemodialysis machine, the dialysate flow direction relative to blood flow is typically:
Answer: Countercurrent, to maximize the concentration gradient for diffusion across the dialyzer membrane
Countercurrent flow maintains a favorable concentration gradient along the entire length of the dialyzer, maximizing solute clearance.