EFFECTS OF NITROUS OXIDE ON THE RESPIRATORY PATTERN OF SPONTANEOUSLY BREATHING CHILDREN DURING ANAESTHESIA

Abstract
The effects of the withdrawal of nitrous oxide from the inspired gas mixture were studied in 10 spontaneously breathing children during nitrous oxide-halothane anaesthesia, before and during surgery, using a computerized system for the measurement, recording and analysis of data. Before surgery the decline in the alveolar nitrous oxide concentration was associated with an increase in minute ventilation (32.7%, P < 0.05), and a decrease in alveolar carbon dioxide concentration (8.4%, P < 0.05). These effects were produced solely by an increase in tidal volume (42.7%, Pper rectum; the depression of carbon dioxide responsiveness was more severe in the group who received papaveretum, and their responses to nitrous oxide elimination were less than, and occurred later than the responses in the group given thiopentone