CABT Medical Equipment Operations Questions and Answers — Questions and Answers
Question 1: A patient connected to a mechanical ventilator triggers a persistent 'High Pressure' alarm. The patient is not coughing, and the tubing is free of kinks and water. What is the MOST likely operational issue or patient condition causing this alarm?
- A partial disconnection of the ventilator circuit from the patient's endotracheal tube.
- A significant leak in the endotracheal tube cuff.
- An increase in airway resistance due to bronchospasm or a mucus plug. (Correct answer)
- The patient's respiratory drive has ceased, leading to apnea.
Correct answer: An increase in airway resistance due to bronchospasm or a mucus plug.
A high-pressure alarm indicates that the ventilator requires more pressure than the preset limit to deliver the set tidal volume. This is typically caused by an obstruction or increased resistance in the airway. Bronchospasm (constriction of the airways) or a mucus plug physically narrows the passage, increasing resistance. A disconnection or cuff leak would cause a 'Low Pressure' alarm. Apnea would trigger a specific 'Apnea' or 'Low Respiratory Rate' alarm.
Question 2: When comparing biphasic and monophasic defibrillators, which of the following is a key operational advantage of biphasic technology?
- Biphasic defibrillators always deliver a higher maximum energy shock (e.g., 360 Joules).
- They require significantly less energy to achieve the same or higher efficacy, reducing potential cardiac damage. (Correct answer)
- Biphasic waveforms are less effective but have a longer battery life.
- Monophasic technology is newer and provides more detailed post-shock ECG analysis.
Correct answer: They require significantly less energy to achieve the same or higher efficacy, reducing potential cardiac damage.
Biphasic defibrillators send the current in two directions, which allows them to terminate arrhythmias with significantly lower energy levels (e.g., 120-200J) compared to monophasic devices (which may go up to 360J). This lower energy reduces the risk of skin burns and damage to the heart muscle. Biphasic technology is the current standard and has largely replaced the older monophasic technology.
Question 3: A technician is preparing an autoclave for a standard sterilization cycle for wrapped surgical instruments. Which combination of temperature, pressure, and time is a widely recognized minimum for effective steam sterilization in a gravity displacement sterilizer?
- 100°C (212°F) at 0 psi for 60 minutes
- 134°C (273°F) at 30 psi for 4 minutes
- 121°C (250°F) at 15 psi for 30 minutes (Correct answer)
- 110°C (230°F) at 10 psi for 45 minutes
Correct answer: 121°C (250°F) at 15 psi for 30 minutes
The standard and widely accepted parameters for steam sterilization of wrapped goods in a gravity displacement autoclave are 121°C (250°F) at a pressure of at least 15 psi for a minimum of 30 minutes. These specific conditions of steam, temperature, pressure, and time are required to effectively kill all microorganisms, including spores. The other options represent incorrect combinations of these critical parameters.
Question 4: A pulse oximeter provides an SpO2 reading by measuring the differential absorption of two wavelengths of light. Which operational principle allows the device to distinguish between arterial and venous blood?
- It measures the static (non-changing) absorption from all tissues and subtracts a baseline value.
- The device only analyzes the pulsatile component of the light absorption, which corresponds to arterial blood flow. (Correct answer)
- It uses a third wavelength of light to specifically isolate and cancel out the signal from venous blood.
- The probe heats the tissue, which temporarily increases arterial flow for a more accurate measurement.
Correct answer: The device only analyzes the pulsatile component of the light absorption, which corresponds to arterial blood flow.
A pulse oximeter identifies arterial blood by detecting the pulsatile nature of its flow, which corresponds to the heartbeat. The device measures the light absorption during both the systolic (pulse) and diastolic (no pulse) phases. The changing, or AC component, of the signal is attributed to the pulsatile arterial blood, while the constant, or DC component, is from non-pulsatile venous blood and tissue. By focusing only on the AC component, it can accurately calculate arterial oxygen saturation (SpO2).
Question 5: During a surgical procedure using a monopolar electrosurgical unit (ESU), the active electrode delivers the cutting current. What is the essential function of the large patient return electrode (dispersive pad)?
- To cool the patient's skin directly under the active electrode.
- To provide a low-resistance path for the electrical current to safely exit the body and return to the generator. (Correct answer)
- To monitor the patient's heart rate and rhythm during the procedure.
- To deliver a secondary, lower-power coagulating current.
Correct answer: To provide a low-resistance path for the electrical current to safely exit the body and return to the generator.
In monopolar electrosurgery, the electrical circuit flows from the ESU generator, through the active electrode, into the patient's tissue, and then must return to the generator. The patient return electrode has a large surface area to safely disperse the current as it exits the body, preventing burns at the exit site. Without this complete and safe path, the current could seek alternative routes and cause significant injury.
Question 6: Which of the following describes a 'free-flow' condition in a large-volume infusion pump?
- The pump accurately delivers the programmed volume but at a slightly slower rate.
- The pump screen freezes, but the infusion stops as a safety precaution.
- The pump alarms for an upstream occlusion between the IV bag and the pump.
- Uncontrolled gravity-fed flow of fluid to the patient after the administration set is removed from the pump's control mechanism. (Correct answer)
Correct answer: Uncontrolled gravity-fed flow of fluid to the patient after the administration set is removed from the pump's control mechanism.
Free-flow is a dangerous condition where fluid flows from the IV bag to the patient under the force of gravity, unregulated by the infusion pump's mechanism. This typically occurs if the tubing is removed from the pump before the roller clamp or another anti-free-flow device is manually closed, potentially leading to a massive overdose.
CABT Medical Equipment Operations Questions and Answers
A patient connected to a mechanical ventilator triggers a persistent 'High Pressure' alarm.
The patient is not coughing, and the tubing is free of kinks and water.
What is the MOST likely operational issue or patient condition causing this alarm?