Equipment

Question 1

Central venour pressure

Answer 1

CVP is the pressure of blood within the right atrium and great veins of the thorax. Normal CVP can be measured from 2 points of reference - sternum or mid axillary line. (so can be zeroed at 2nd intercostal space in the mid-axillary line).

Normally performed at the END of expiration.

Question 2

Wright respirometer

Answer 2

Measures TV & min vol (only unidirectional flows); minimum flow of 2 litres is required for respirometer to function accurately. It over-reads at high and under reads at low flows.

Is affected by water vapour- Water condensation from the expired gases causes the pointer to stick, thus preventing it from rotating freely.

Question 3

maximum oxygen concentration achieved by oxygen concentrators is

Answer 3

About 95%

Question 4

What does DINAMAP stand for?

Answer 4

Device for Indirect Non-invasive Assessment of Mean Arterial Pressure.
Function based on oscillotonometry.

Question 5

Natural frequency of a mass-string dynamic oscillator is inversely proportional to what?

Answer 5

Square root of mass.

Question 6

Non-invasive BP: which Korotkoff sounds correspond with SBP and DBP?

Answer 6

1st sound - SBP.
2nd and 3rd- muffling and resurgence.
4th /5th- DBP (both tends to be higher than direct measure).

Maximum oscillation = MAP

MAP = DBP + (SBP-DBP)/3.
So BP of 120/70 -> MAP of 86.7

Question 7

What does laser stand for?

Answer 7

Light Amplification by Stimulated Emission of Radiation.

A coherent beam of light with specific wavelength in IR/ visible/ UV regions of the electromagnetic spectrum.

Question 8

What are the 3 characteristics of laser light particles?

Answer 8

The particles are photons.

1- monochromatic (single wavelength)
2- coherent (in phase)
3- collimated (parallel/ aligned particles)

Question 9

What components are lasers composed of?

Answer 9

1- lasing medium
2- energy source/ lamp
3- optical resonator/ cavity (for light beam production)

Question 10

Equation for soda lime reaction with CO2

Answer 10

CO2 + 2NaOH —> Na2CO3 + H2O + heat

Na2CO3 + Ca(OH)2 —> 2NaOH + NaCO3

Question 11

X-rays and gamma rays are ionising radiations? And UV rays are non-ionising?

Answer 11

True and true.

Question 12

Is thermodilution technique in measuring cardiac output accurate in rapid volume infusions, R-sided valvular disease, L to R intracranial shunt, and in dysrhythmias?
And if top of pulm artery catheter is completely wedged?

Answer 12

No and no

Question 13

What is the zone of risk in the operating room?

Answer 13

It is the area where mixtures of Anaesthetics agents may be explosive. Extends to 25cm from any part of anaesthetic apparatus or the patient’s airway containing the anaesthetic mixture.

Question 14

ECG interference in intubated and ventilated patient can be due to?

Answer 14

Patient can behave like one plate of a capacitor (with electric lamp acting as the other plate; AC can pass across an air gap).

Question 15

What type of flowmeter is the rotameter?

Answer 15

Constant-pressure, variable orifice flowmeter.

Calibration depends on both density and viscosity.

Question 16

How is the Bain coaxial breathing system checked?

Answer 16

Via Pethick’s test.
Inner FGF tube occluded @ distal end and reservoir bag filled by closing expiratory valve; then O2 flush with tube unobstructed –> bag should empty secondary to gas entrainment (provided inner tube is not dislodged, which would increase dead space in circuit).

Question 17

Give the 5 major filtration mechanisms of how breathing system filters (BSFs) work.

Answer 17

Interception.
Inertial impaction.
Electrostatic attraction (works for charged and neutral particles).
Diffusion (Brownian motion).
Gravitational settling (larger particles).
(PPS will pass through most easily; PPS usually measure 0.05-0.5micrometer in diameter).

BSFs function as filtering function of nasopharynx, reducing contamination of breathing equipment, and role in warming and humidification.

Question 18

What is the most appropriate technique to disinfect a fibreoptic endoscope?

Answer 18

Immersion in 2% glutaradehyde solution, as it is non-corrosive and does not damage lens or fibreoptic bundles of the scope. Effective against bacteria, mycobacterium, viruses, and spores.

Question 19

Which spectrum do X-rays and gamma rays lie in?

Answer 19

They have the highest frequency and lie in the UV spectrum.