CBET Infusion Pumps and Medication Delivery Systems

Question 1

A syringe pump generates an 'occlusion downstream' alarm. The patient's IV site appears patent. What is the MOST likely next step for a BMET troubleshooting this pump?

Accepted Answer

Inspect the IV line for kinks, closed clamps, or infiltration at the catheter site

Answer

A downstream occlusion alarm means the pump's pressure sensor detected resistance distal to the syringe. The most common causes are a clamped or kinked IV line, a closed stopcock, or a failed/infiltrated IV catheter. Adjusting the threshold would mask a real clinical problem, and replacing the drive mechanism is unwarranted before ruling out external causes.

Question 2

What is the primary patient safety advantage of a 'smart pump' drug library (DERS — Dose Error Reduction Software) over a standard volumetric infusion pump?

Accepted Answer

Alerting the clinician when a programmed dose falls outside safe soft and hard limits for a specific drug

Answer

DERS drug libraries contain facility-customized dose limits (soft limits trigger an alert; hard limits prevent programming) for each drug by care area. When a clinician enters a dose, the pump checks it against the library and warns of potential 10-fold errors or protocol deviations. This directly targets programming errors, which are a leading cause of IV medication adverse events.

Question 3

A BMET is performing a flow-rate accuracy check on a volumetric infusion pump using gravimetric testing. For most general-purpose volumetric pumps, what is the acceptable accuracy tolerance per manufacturer and AAMI standards?

Accepted Answer

±5%

Answer

AAMI and most pump manufacturers specify ±5% flow rate accuracy as the acceptable tolerance for volumetric infusion pumps under steady-state conditions. This is the standard threshold used in PM protocols. A ±1% tolerance is unrealistic for peristaltic mechanisms; ±10–20% would be clinically unsafe for high-alert medications.

Question 4

Which component of a peristaltic (linear) infusion pump mechanism most directly controls flow rate accuracy and is the most common wear item requiring replacement or inspection during PM?

Accepted Answer

The peristaltic fingers or cam mechanism and IV tubing segment

Answer

In a linear peristaltic pump, the fingers or cam sequentially compress a dedicated tubing segment to push fluid. As the tubing fatigues (loses elasticity) or the fingers wear, the volume displaced per cycle changes, degrading flow rate accuracy. This is the mechanism by which the pump moves fluid and the component most subject to wear.

Question 5

A patient-controlled analgesia (PCA) pump is programmed with a demand dose of 1 mg morphine, a lockout interval of 10 minutes, and a 4-hour limit of 20 mg. A family member is found pressing the PCA button repeatedly on behalf of the patient. Why is this a critical safety concern the BMET should report?

Accepted Answer

The 4-hour limit is the only safety barrier, and rapid button presses by a non-patient can deliver that maximum dose to a patient who may not need it, causing respiratory depression

Answer

PCA therapy is designed around the 'patient' being awake and self-limiting — an opioid-induced sedated patient will stop pressing. A proxy pressing the button can deliver the full 4-hour dose limit to a sedated patient without the natural protective feedback mechanism, risking dangerous respiratory depression. The lockout still applies per press, but the 4-hour ceiling can still be reached.

CBET - Certified Biomedical Equipment Technician Practice Test

CBET - Certified Biomedical Equipment Technician Practice Test

CBET Infusion Pumps and Medication Delivery Systems