The effect of extradural analgesia combined with light general anaesthesia and spontaneous ventilation on arterial blood-gases and physiological deadspace.
Arterial Po2 and Pco2 were measured at half-hourly intervals in eleven patients anaesthetized for lower limb vascular surgery with a combination of nitrous oxide 67% and halothane 0.3-0.5% in oxygen, and an extradural injection of bupivacaine. Values for the alveolar-arterial oxygen tension difference, physiological deadspace and deadspace-tidal volume ratio were calculated. Although both the alveolar-arterial oxygen tension difference and physiological deadspace were large, spontaneous ventilation was adequate to maintain both Po2 and Pco2 of arterial blood at acceptable values. Over the course of 2 hr following the extradural injection there were no significant changes in any measured value.
D000328:Adult; D000368:Aged; D000767:Anesthesia, Epidural; D000768:Anesthesia, General; D002045:Bupivacaine; D002245:Carbon Dioxide / Q000097:blood*; D006221:Halothane; D006801:Humans; D008297:Male; D008875:Middle Aged; D009609:Nitrous Oxide; D010100:Oxygen / Q000097:blood*; D012119:Respiration; D012126:Respiratory Dead Space
D002245:Carbon Dioxide; D009609:Nitrous Oxide; D010100:Oxygen; D006221:Halothane; D002045:Bupivacaine