American Medical Research Expedition to Mt Everest (AMREE) and Alveolar Gas Sampling – 25 Years On

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A review of alveolar gas sampling above 8000m by the 1981 American Medical Research Expedition to Mt Everest (AMREE). Methods 42 samples of alveolar gas were collected in pre-evacuated aluminium canisters from three locations – Camp 5 (8050m – 282.5 & 284.7 mmHg), Camp 6 (8400m – 267.1 mmHg) and the summit of Mt Everest (8848m – 253 mmHg). These were subsequently transported back to the laboratory and placed in a pre-evacuated chamber and analyzed in a mass spectrometer. Results Of the 34 samples deemed suitable for analysis, 27 were taken from 8050m (PAO2 = 36.1 mmHg, PACO2 = 11 mmHg, R = 0.78), 3 at 8400m (PAO2 = 36.7 mmHg, PACO2 = 8 mmHg, R = 0.82) and 4 at 8848m (PAO2 = 37.6 mmHg, PACO2 = 7.5 mmHg, R = 1.49). Conclusion The AMREE team rejected the summit value of alveolar PO2 (37.6 mmHg) since the calculated R value was deemed to be too high (1.49) and instead, calculated a new value: 35 mmHg. The small difference between the measured and calculated values (2.6 mmHg) may be explained by the “Lactate Paradox”. By measuring alveolar PO2 and PCO2, together with lactate concentrations, the 2007 Xtreme Expedition to Mt Everest intends to build upon AMREE's pioneering work and clarify this outstanding question.