Effect of Artificial Hyperventilation on Potassium Metabolism and pH in Anesthetized Patients.

Kim,  Ae Ra; Jeon,  Jae Kyu; Lee,  Won Jung

doi:1982.15.2.179

Clinical Research Article

Korean Journal of Anesthesiology 1982;15(2):179-183.
DOI: https://doi.org/10.4097/kjae.1982.15.2.179

Effect of Artificial Hyperventilation on Potassium Metabolism and pH in Anesthetized Patients.

¹Department of Anesthesiology, keimyung University College of Medicine, Taegu, Korea.
²Department of Physiology, Kyungpook University School of Medicine, Taegu, Korea.

Abstract

In order to determine the relationship between acid-base balance and K+ metabolism in patients whi controlled respiration during surgery, 20 patients under general anesthesia were studied. Anesthesia was induced with 2% thiopental and was maintained with halothane. Suxamethonium was used for intubation. During surgery, the respiration of the patient was controlled by a volume controlled respirator with tidal volume of 800ml and a rate of 12/min. Blood and urine samples were collected before anesthesia, and 30 and 60 minutes thereafter. REsults were as follows: Hyperventilation induced by artificial respiration during surgical anesthesia produced a significant decrease in PaCO2 from 36.1+/-1.3mmHg to 19.9+/-1.5mmHg at 30 min, and to 20.1+/-1.7mmHg at 60 min. Hyperventilation increased arterial pH from 7.41+/-0.008 to 7.49+/-0.028 at 30 min, and 7.47+/-0.011 at 60 min. Hyperventilation produced a significant decrease in serum concentration of K+ from 4.04+/-0.12 to 3.75+/-0.08mEq/l at 30min, and 3.62+/-0.05 mEq/l at 60min. Urinary excrets of K+ was not significantly altered during the hour of the hyperventilation. These results suggest that hypokalemia followed by respiratory alkasisis mainly due to the movement of K+ from extracellular to intracellular compartments rather than a change in renal excretion of K+.