Anesthesia Question Bank

Sample

1. In a patient with a T4 injury, a safe technique for cystoscopy includes:

In a high (T4) spinal cord injury, autonomic dysreflexia is a major risk during bladder instrumentation; a total intravenous technique with propofol and remifentanil reliably blunts the response and is a safe choice.

Sample

2. Concerning osmolality

Osmolality of a solution is determined by the total concentration of dissolved or colloid particles within the solution. It depends on the number rather than the type of particles present. One mole of sodium chloride dissolved in 1 kg of water has an osmolality of 2 osmol/kg, as sodium chloride freely dissociates into the 2 particles, Na and Cl. One mole of urea (which does not dissociate) in 1 kg of water has an osmolality of 1 osmol/kg. The concentration of Page 33 particles, i.e. the osmolality, within the ICF and the ECF is always equal during equilibrium. Plasma osmolality is approximately 290 mosmol/kg and may be estimated from the formula: Plasma osmolality (mosmol/kg) = 2[Na] (mmol/L) + Blood glucose (mmol/L) + Blood urea (mmol/L) Read the question carefully! The units for osmolality are mmol/kg and not mmol/L.

Sample

3. A large A–V shunt causes:

A large arteriovenous shunt increases cardiac output and tends to cause warm peripheries; the keyed answer lists cold extremities, but a high-output AV shunt usually produces warm, well-perfused extremities. [REVIEW: keyed answer (cold extremities) may be incorrect - a large A-V shunt classically produces a high-output state with warm extremities and increased cardiac output.]

Sample

4. In a 2-year-old child:

A 2-year-old child's maintenance fluid requirement is roughly 100 mL/kg/day for the first 10 kg (4-2-1 rule), so the keyed answer reflects approximately 100 mL/kg/day for the relevant weight range.

Sample

5. The following can be used to measure carbon dioxide in expired gases (capnography)

Capnography, the measurement of CO2 in expired gases, is undertaken using infrared absorption, mass spectrometry and Raman analysis. The majority of capnographs rely on infrared absorption. Clark electrode and paramagnetic analyser are used for measuring oxygen tension.

Sample

6. Concerning skeletal muscle

Skeletal muscle comprises multinucleated cells with no syncytial bridges between cells. The resting membrane potential is approximately - 90 mV. The action potential lasts between 2 to 4 ms. During contraction, the width of the A bands is constant, whereas the width of the I bands is reduced. During a complete tetanus, the tension developed is approximately 4 times that developed by an individual twitch contraction. Skeletal muscle is under somatic nervous control.

Sample

7. Sevoflurane

Sevoflurane has a lower blood/gas partition coefficient than isoflurane (0.6 vs 1.4). It does not sensitise the myocardium to catecholamines and has relatively little effect on the cardiovascular system.The MAC of sevofluarane is approximately 2% compared to 6% for desflurane. It is less pungent than desflurane and is therefore suitable for inhalational induction. Because of the Page 53 lower blood/gas and oil/gas partition coefficients, sevoflurane has a faster washout than halothane

Sample

8. Electroencephalography (EEG) may be altered by the following

The EEG reflects the spontaneous electrical activity of cortical pyramidal neurones arising from inhibitory and excitatory postsynaptic potentials. The EEG may be altered by a large number of physiological factors, including temperature, arterial carbon dioxide tension, hypoxaemia, and electrolyte abnormalities. Anaesthetic drugs also affect EEG morphology, depending on the drugs used and the depth of anaesthesia

Sample

9. Hepatic first-pass metabolism

Transdermal, sublingual and parenteral (IV, IM, SC) routes avoid the hepatic portal circulation and hence the hepatic first pass metabolism. A variable proportion of the drug given rectally will be absorbed into the portal circulation, therefore first pass metabolism is not totally avoided. Drugs with high hepatic extraction ratios undergo substantial first pass metabolism.

Sample

10. In 70 kg patient one unit of platelet concentrate should increase platelet count:

One unit of platelet concentrate raises the platelet count by about 5,000 to 10,000/mm3 in an average adult; the keyed answer/options are partly corrupted, but the intended value is a modest rise per unit. [REVIEW: options a and d are identical (2000-5000) - the typical rise is closer to 5,000-10,000 per unit, so the duplicated option set is flawed.]