Medical Equipment Function Flashcards

An electrosurgical unit (ESU) is being used in monopolar mode. For the electrical circuit to function correctly and safely, which component is essential to complete the circuit by returning the current to the generator?

Answer: A dispersive patient return electrode

In monopolar electrosurgery, the electrical current flows from the active electrode, through the patient's body to the surgical site, and then must be safely returned to the ESU generator. A large dispersive pad, known as the patient return electrode, is placed on the patient's body away from the surgical site to collect the current and complete the circuit, preventing burns at unintended sites.

A hemodialysis machine is being used to treat a patient with renal failure. The primary mechanism by which waste products like urea are removed from the blood into the dialysate is:

Answer: Diffusion

Hemodialysis primarily relies on diffusion to remove metabolic waste products. These substances, like urea, are in high concentration in the patient's blood and move across the semipermeable dialyzer membrane into the dialysate, where their concentration is low or zero. Ultrafiltration is the primary method for fluid removal, not solute removal.

When comparing modern biphasic defibrillators to older monophasic models, what is the primary functional advantage of using a biphasic waveform?

Answer: It achieves the same or higher defibrillation success at a lower energy level.

Biphasic waveforms are more effective at terminating ventricular fibrillation because the current flows in one direction and then reverses. This dual-direction shock allows for successful defibrillation using significantly lower energy levels compared to monophasic shocks, which reduces the risk of myocardial injury and skin burns.

A technician is explaining the function of an anesthesia machine to a new colleague. What is the primary role of the vaporizer component within the machine?

Answer: To convert liquid anesthetic agent into a precisely controlled vapor.

The vaporizer is a critical component of an anesthesia machine designed to change a liquid anesthetic agent into its vapor state and then add a specific, controlled amount of that vapor to the fresh gas flow going to the patient.

A new infusion pump is delivered to the hospital. The specifications state it uses a peristaltic mechanism. How does this type of pump move fluid through the IV tubing?

Answer: By using rotating rollers or 'fingers' to sequentially compress the tubing.

Peristaltic pumps function by using a set of rotating rollers that press against a flexible tube. As the rollers move along the tube, they create a pocket of fluid that is pushed forward, mimicking the biological process of peristalsis. This mechanism allows for controlled fluid delivery without the pump's components directly contacting the fluid.

In a clinical laboratory, a centrifuge is used to process a whole blood sample collected in a tube with an anticoagulant. The primary function of the centrifuge in this application is to:

Answer: Separate components like plasma, platelets, and red cells based on density.

A centrifuge spins samples at high speed, creating a strong centrifugal force. This force causes the denser components of the blood, like red blood cells, to move to the bottom of the tube, while less dense components, like plasma, remain at the top. This separation is essential for a wide variety of diagnostic tests.