The Effects of the Findings in Pulmonary Function Test and Anesthetic Technique on the Arterial Blood Gas Analysis in Elderly Patients

Postoperative hypoxemia in elderly patients caused to suffer tissue hypoxia and injury to vital organs.

Thirty-two elderly patients over 65 years age with normal or abnormal findings in pulmonary function test were at random either epidural analgesia with 2% lidocaine and 0.5% bupivacaine or general anesthesia with diazepam, pethidine, pancuronium or vecuronium. N₂0 / 0₂ for lower abdominal or lower extremity surgery. The arterial blood gas analysis was performed at preanesthetic, 30min after extubation(or 30min after the end of surgery in epidural analgesia groups) and postoperative lday.

The results were as follows:

1) In general anesthesia group with normal findings in pulmonary function test(PET). the PH decreased, and PaCO₂ increased on 30min after extubation compared to preanesthetic values, but the PH increased, and base excess decreased significantly on the postoperative lday.

2) In epidural analgesia group with normal findings in PFT, the values of arterial blood gas analysis were no changed on 30min after the end of surgery and postoperative lday compared to preanesthetic values.

3) In general anesthesia group with abnormal findings in PFT, the PaCO₂ increased, and Pa0₂ and oxygen saturation decreased significantly on 30min after extubation, but the PH increased, Pa0₂ remained reduced on the postoperative lday compared to preanesthetic values.

4) In epidural analgesia group with abnormal findings in PFT, the values of arterial blood gas analysis were no changed on 30min after the end of surgery, but the PH increased, PaCO₂ decreased significantly on the postoperative lday compared to preanesthetic values.

It appears from these findings that epidural analgesia is preferable to general anesthesia in lower abdominal or low extremity surgery for elderly patients with abnormal findings in PFT.