Trans-oesophageal echocardiography

Concerning trans-oesophageal echocardiography

(a) the Doppler probe employs high-frequency sound waves

(b) the Doppler effect is due to a change in frequency of the ultrasound waves

(c) ultrasound gives a precise measure of cardiac output

(d) the speed of medical ultrasound is 1540 m/s

(e) medical ultrasound passes better through air than blood

Strain gauge

A strain gauge can be used to measure

(a) gas flow

(b) intensity of light

(c) arterial blood pressure

(d) forearm blood flow

(e) force of muscle contraction

Electrical safety

Regarding electrical safety

(a) an electrical current of 5mA passing through the body will cause a tingle

(b) class II electrical equipment must be double insulated

(c) class III equipment can only work with a low voltage (<24 V)

(d) the leakage current from any equipment that can come in contact with the heart must be less than 50mA

(e) anaesthetic proof (AP) may be used in the zone of risk 5–25cm from an enclosed medical gas system

Student’s t-test

Student’s t-test

(a) is used to analyse normally distributed data

(b) is used for comparing a single small sample

(c) should be used as a one-tailed test whenever possible

(d) deals with the problems associated with inference based on ‘small’ samples

(e) is typically used to compare the means of two populations

Haemofiltration

 Regarding the physiological principles underlying haemofiltration

(a) the pore size of the membrane allows molecules up to 50, 000 daltons to pass through

(b) an ultrafiltrate of up to 1000 ml per hour can be formed

(c) plasma water is removed by convective flow

(d) the buffer of choice is bicarbonate in very low concentrations

(e) transmembrane potential equals hydrostatic pressure _ oncotic pressure

Medical piped gases

With regard to medical piped gases

(a) the nitrous oxide pressure is 4 bar (4 · 105 Pa)

(b) after maintenance of O2 pipes the O2 analyser is used to test the integrity of the system

(c) the non-interchangeable screw thread (NIST) has one diameter in the shaft which is specific for each gas

(d) the Schrader probe has a non-return valve (e) the pipeline oxygen supply pressure enters the machine at 420 kPa (60 psi) pressure

Substance conversion

With regard to a substance

(a) 1 mol equals 0.012 g carbon-12

(b) 1 mol occupies 2.24 l at s.t.p.

(c) In 1 mol of any substance are 6.022 · 1023 molecules

(d) mole is the SI unit of volume

(e) one gram molecular weight of any gas occupies the same volume