Respiratory alkalosis and hypokalemia in dogs exposed to simulated high altitude

¹ Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland

Exposure of restrained, unanesthetized dogs to a simulated altitude of 30,000 ft consistently resulted in respiratory alkalosis and marked hypokalemia. When alkalosis was prevented by increasing the pCO₂ of inspired air during decompression, a smaller but statistically significant decrease in plasma potassium concentration still occurred. In comparison with previous studies, the hypokalemia observed in these restrained, unanesthetized dogs was greater than that found in either unrestrained or anesthetized dogs subjected to the same decompression stress. Consequently, the suggestion is made that in the unanesthetized, restrained dog, the hypokalemic response not attributable to respiratory alkalosis is of adrenal mediation and results from the "stress" of restraint plus hyperventilation, rather than to hypoxemia or the decompression stress, per se.