Observations of Blood Lactate and Pyruvate Levels and Excess Lactate Production During and After Anaesthesia With and Without Hyperventilation

Abstract

Arterial blood levels of lactate and pyruvate and the production of excess lactate were studied in two groups of patients. One group of ten patients was anaesthetized with <1 per cent halothane, nitrous oxide and oxygen and allowed to breathe spontaneously. The second group of twelve patients was anaesthetized with nitrous oxide and oxygen, and additional trichloroethylene or papaveretum, and deliberately hyperventilated. No significant changes were found in lactate or pyruvate during anaesthesia in the first group, but there was a significant increase in the lactate: pyruvate ratio half an hour after recovery from the anaesthetic. Significant excess lactate production occurred during anaesthesia in the second group after hyperventilation had been in progress for half an hour. The excess lactate increased after 1 hour of hyperventilation and further increases were found half an hour after recovery from the anaesthetic. These findings are discussed in relation to the observed changes in blood-gas levels and acid-base balance and to the current knowledge of carbohydrate metabolism. BRITISH JOURNAL OF ANAESTHESIA TABLE I Age, sex and diagnosis of patients studied.

Elevated lactate during psychogenic hyperventilation

“…Passive overbreathing under anaesthesia has been shown to induce hyperlactataemia in various studies 9 10. Furthermore, active voluntary overbreathing in individuals with panic disorders has been related to the development of a marked hyperlactataemia as well 11 12.…”