EDAIC Clinical Measurement and Physics 2

Question 1

Which property of a gas is described by the Beer-Lambert law as it applies to pulse oximetry?

Accepted Answer

Light absorption is proportional to concentration and path length

Answer

Beer-Lambert law states that absorbance is proportional to the product of molar absorptivity, concentration, and path length, forming the basis of oximetry.

Question 2

In a rotameter (variable-area flowmeter), what keeps the bobbin floating at a fixed height for a given flow rate?

Accepted Answer

Balance between gravity and the upward drag force of gas flow

Answer

The bobbin reaches equilibrium when the upward viscous drag and pressure forces from gas flow exactly balance the bobbin's weight.

Question 3

What is the clinical implication of the Hagen-Poiseuille equation when a tracheal tube is halved in internal diameter?

Accepted Answer

Resistance increases 16-fold

Answer

Hagen-Poiseuille states resistance is proportional to 1/r⁴; halving the radius (r→r/2) increases resistance by 2⁴ = 16 times.

Question 4

A pressure transducer for invasive blood pressure monitoring is calibrated at heart level. Raising the transducer 10 cm above heart level will:

Accepted Answer

Falsely lower the displayed pressure by ~7.5 mmHg

Answer

Every 13.6 cm of height difference corresponds to ~10 mmHg; raising the transducer 10 cm reduces the hydrostatic column and causes a false low reading of ~7.5 mmHg.

Question 5

Which electromagnetic frequency range is used by a standard nerve stimulator to produce a 'train-of-four' stimulus?

Accepted Answer

2 Hz square-wave pulses delivered four times

Answer

Train-of-four uses four supramaximal square-wave pulses at 2 Hz (0.5-second intervals), allowing neuromuscular block assessment via T4:T1 ratio.

EDAIC - European Diploma in Anesthesiology and Intensive Care Practice Test

EDAIC - European Diploma in Anesthesiology and Intensive Care Practice Test

EDAIC Clinical Measurement and Physics 2