Serum Potassium Levels in Hyperventilated Dogs

Abstract

How much pulmonary ventilation an anesthetized patient should have is a difficult question to answer. Since all general anesthetic agents now employed cause some respiratory depression, most anesthesiologists augment their patient's pulmonary ventilation by positive pressure applied intermittently either by hand or by means of a mechanical ventilator. Many anesthesiologists believe that since euventilation is difficult to achieve, passive hyperventilation should be employed, that is, always to err on the side of a high p O2 and low p COa in the arterial blood. Some possible adverse physiological effects of a markedly lowered p C02 have been suggested by the work of Kety(l), Sugioka(2), and others. These effects relate principally to the vasoconstrictive effect of a low p COa upon certain blood vessels with a resulting ischemia of the supplied area. Other possible adverse effects of hyperventilation, however, relate to electrolyte changes in blood plasma, principally those of potassium and sodium. Brown, et aE., noted no consistent change in plasma potassium although urinary potassium excretion increased during hyperventilation ( 3 ) . Robinson (4) has recently presented evidence that hyperventilation is not deleterious to the patient, even though certain marked chemical changes may occur in the blood. Following a marked, passive hyperventilation, he noted a significant drop in serum potassium and sodium in awake subjects but only a slight drop in serum potassium in anesthetized subjects. Von F. Schaub found a large decrease in serum potassium in actively hyperventilated subjects(5). Sieker showed a relation of blood glucose to the serum potassium under hypoxic hyperventilation( 6). In order to clarify these discrepancies the foIIowing study was undertaken.Method. To investigate serum potassium during prolonged passive hyperventilation, 1 7 * Present address: Univ. of Pennsylvania Med. School, Philadelphia.mongrel dogs, average weight 13 kg, were studied. After anesthesia was induced and maintained a t moderate levels with halothane in room air, the dogs were heparinized and control blood samples were drawn. The dogs were then passively hyperventilated with a sinusoidal pump (intermittent positive pressure) in a non-rebreathing system for 6 hours. Blood samples were drawn at intervals. The pump was stopped and spontaneous respirations resumed for about 20 minutes at which time another control blood sample was drawn. All dogs were allowed to survive at least 2 days, some for several weeks, before being sacrilficed.All blood was drawn through polyvinyl catheters directly into siliconed, heparinized syringes containing 1 cc of mercury. The syringes were gently inverted several times immediately prior to whole blood analysis. pH's and COa contents were done on whole blood and potassiums were determined in serum (blood clotted with protamine and fibrin removed).Serum potassiums were determined with flame photometry on 13 dogs. Blood gas contents were determined with the method of Van Slyke and Neill, and pH's with glas...

Changes of Serum Potassium During Renal Homotransplantation

“…In the presently reported series, tubocurarine chloride and hyperventilation were used in 11 of the 12 recipients. Hyperventilation has been reported to lower serum potassium concentrations in dogs, 9 and the same effect has been noted with inhalational anesthesia. 10 By comparison, the influence of succinylcholine upon serum potassium must be considered undesirable since this agent has been reported to contribute to the mobilization of potassium, 10,11 as noted by Popovtzner et al (unpublished data).…”