Chapter 6 · MCQ Read Mode

Biomedical Instrumentation- II

Defibrillation terminates ventricular fibrillation by:

Which of the following rhythms should NOT be treated with a defibrillator shock?

Compared with a monophasic waveform, a biphasic defibrillator waveform:

The essential difference between defibrillation and synchronised cardioversion is that cardioversion:

Energy stored in the capacitor of a DC defibrillator is given by:

Conductive gel is applied to defibrillator paddles principally to:

Internal paddles applied directly to the heart during cardiac surgery require an energy of about:

Asynchronous (fixed-rate) pacing is potentially dangerous because a stimulus may:

A pacemaker that fails to inhibit when an intrinsic beat occurs is showing:

Transcutaneous external pacing has the principal disadvantage that it is:

The tiered therapy of an implantable cardioverter-defibrillator begins for slower ventricular tachycardia with:

The commonest cause of an inappropriate shock from an implantable cardioverter-defibrillator is:

A patient with a permanent pacemaker requires surgery. Which precaution is most important regarding surgical diathermy?

Surgical diathermy uses frequencies above about 300 kHz because at such frequencies the current:

In monopolar electrosurgery, the purpose of the large patient return plate is to:

The waveform used for pure cutting in electrosurgery is:

Bipolar diathermy is preferred to monopolar diathermy in a patient with a permanent pacemaker because:

An unseen bowel burn during laparoscopic monopolar diathermy is most characteristically caused by:

A surgeon repeatedly asks for the diathermy power to be increased. The most important action is to:

The process by which an excited atom struck by a photon emits a second identical photon is:

A population inversion in a laser medium means that:

The carbon dioxide laser is described as a precise cutting laser because its 10,600 nm radiation is:

Which laser penetrates most deeply into tissue and is therefore used for coagulating large vessels and debulking tumours endoscopically?

The helium-neon laser is most commonly used in surgical systems as:

Retinal injury is a particular hazard with lasers operating in the wavelength range:

Protective eyewear worn during laser surgery must be:

Short-wave diathermy operates at the internationally allocated frequency of:

The capacitive (condenser field) method of short-wave diathermy heats which tissue preferentially?

Microwave diathermy is particularly hazardous to the eye because the lens:

Therapeutic ultrasound at 3 MHz rather than 1 MHz is chosen when the target tissue is:

The applicator of a therapeutic ultrasound unit must be kept constantly moving in order to:

A high beam non-uniformity ratio in a therapeutic ultrasound head indicates:

Chronaxie is defined as the pulse duration required to excite a muscle at an intensity of:

In interferential therapy, two medium-frequency currents are used because they:

Conventional high-frequency TENS relieves pain principally by:

Pain relief produced by acupuncture-like low-frequency TENS can be reversed by naloxone, which indicates that it is mediated by:

TENS electrodes must not be placed over the anterior neck because stimulation of the carotid sinus may cause:

Deep heating modalities are contraindicated in a patient with a metal implant because metal:

Pulsed short-wave diathermy differs from continuous short-wave diathermy in that it:

In haemodialysis, the removal of urea from the blood occurs principally by:

Blood and dialysate flow in opposite directions through a dialyser in order to:

The blood pump of a haemodialysis machine is a peristaltic roller pump because:

A conductivity alarm on a dialysis machine protects the patient against:

The air detector in the venous line of a dialysis circuit is critical because it prevents:

Cellulosic dialysis membranes were largely replaced by synthetic membranes because cellulosic membranes:

Disequilibrium syndrome during early dialysis sessions is caused by:

Chloramine must be removed from dialysis water by activated carbon because it causes:

Extracorporeal shock waves fragment a urinary stone while sparing soft tissue because:

In an electrohydraulic lithotripter using an ellipsoidal reflector, the stone is positioned at:

Shock wave delivery in modern lithotripters is often synchronised to the ECG in order to:

Which is an absolute contraindication to extracorporeal shock wave lithotripsy?

Extracorporeal shock wave therapy applied to plantar fasciitis differs from lithotripsy in that it aims to:

On an anaesthesia machine, oxygen is placed last (most downstream) in the flowmeter manifold so that:

The hypoxic guard on an anaesthesia machine ensures that:

Which monitor provides the definitive confirmation that a tracheal tube is correctly placed in the trachea?

A negative pressure ventilator such as the iron lung works by:

In a pressure-cycled ventilator, a fall in lung compliance will result in:

Pressure support ventilation is described as flow-cycled, meaning that inspiration ends when:

Positive end-expiratory pressure is applied principally to:

In lung-protective ventilation for ARDS, the tidal volume is set at approximately:

The commonest and most immediately lethal hazard associated with mechanical ventilation is:

A syringe pump is preferred to a volumetric peristaltic pump when:

A characteristic problem of syringe pumps delivering vasoactive drugs is:

An infusion system in which the pump rate is automatically adjusted from a continuously measured blood glucose value is an example of:

Free flow of intravenous fluid when a giving set is removed from a volumetric pump is prevented by:

The physiological effect of an electric shock is determined principally by the:

The 'let-go' current at mains frequency, above which a person can no longer release a conductor, is approximately:

Microshock differs from macroshock in that microshock:

A patient with a saline-filled intracardiac pressure line is described as electrically susceptible and must be connected only to equipment of class:

Leakage current in a piece of medical equipment:

Current flowing between two ECG electrodes through the patient during normal operation is called:

Leakage current limits in the standards are specified both in normal condition and in single fault condition because:

Equipotential bonding in a critical care area protects the patient by ensuring that:

A residual current device set to trip at 30 mA:

In an electrical safety test, the protective earth continuity resistance of a Class I device should typically not exceed:

Insulation resistance in an electrical safety test is measured by applying:

The measuring device network built into an electrical safety analyser is designed to:

Electrical safety testing of a medical device should be performed: