A Study of Carbon Dioxide Tensions During Halothane Anaesthesia Using the Magill Circuit

Abstract

In thirteen patients capillary blood samples were obtained for measurement of pH and Pco a immediately after the induction dose of thiopentone, after 45 minutes of 2 per cent halothane breathed spontaneously (with nitrous oxide and oxygen), and 30 minutes postoperatively. A very variable rise in Pco 2 was observed which did not correlate well with changes in pulse rate, blood pressure, respiratory frequency, respiratory minute volume, or with the age of the patient. A single measurement of respiratory minute volume with a Wright respirometer was of no value in indicating which patients had the greatest carbon dioxide retention. The return of Pco, to normal values in the postoperative period was found to be rapid and, for practical purposes, complete in 30 minutes.

Cardiac Effects of Halothane and Adrenaline in Hare-Lip and Cleft-Palate Surgery

“…Although care was taken to avoid undue respiratory depression, some carbon dioxide retention is unavoidable with this technique. Nevertheless the degree and rapidity of the rise in pulse rate suggest that the systemic absorption of adrenaline, rather than hypercarbia, was the cause (Ivanov, Waddy and Jennings, 1967). Other authorities have noted electrocardiographic evidence of cardiac arrhythmias during halothane administration, with widely varying doses of adrenaline both in dogs (Raventos, 1956;Sharma, 1967) and in man.…”