Sun28November0333PM 42

A normally fit and well 24-year-old patient is scheduled for an urgent appendicectomy. The patient weighs 70 kg and is positioned for a rapid sequence induction.

Which one of the following compartments is likely to have the single best oxygen reserve in this patient prior to preoxygenation?

(Please select 1 option)

Plasma

Myoglobin

Lung

Red blood cells Correct

Interstitial space

Explanation

Compartment Factors Room air (mL) 100% O2 (mL)

Lung FAO2, FRC 630 2850

Plasma PaO2, DF, PV 7 45

Red blood cells Hb, TGV, SaO2 788 805

Myoglobin 200 200

Interstitial space 25 160

Oxygen reserves in the body, with room air and after oxygenation.

FAO2 alveolar fraction of oxygen rises to 95% after administration of 100% oxygen (CO2 = 5%)

FRC 2,500-3,000 mL in medium sized adults

PaO2 partial pressure of oxygen dissolved in arterial blood (80 mmHg breathing room air and 500 mmHg breathing 100% oxygen)

DF dissolved form (0.3%)

PV plasma volume (3L)

TG total globular volume (5L)

Hb haemoglobin concentration

SaO2 arterial oxygen concentration (98% breathing air and 100% when preoxygenated)

Answer Statistics

1

3%

2

12%

3

33%

4

52%

5

3%

Times answered: 236