Effect of secobarbital and morphine on arterial blood gases in healthy human volunteers.
Secobarbital is still widely used as a hypnotic and morphine as an analgesic perioperatively in surgical patients. Their combination is often used as a preanesthetic medication. Although their ventilatory depressant effect is recognized, the resulting blood gas changes have not been studied as yet adequately in a sufficiently large population of healthy volunteers. Therefore this study was undertaken. Thirty healthy volunteers who gave valid written consent were studied. Secobarbital 2.0 mg/kg intravenously caused a significant (P < .05) decrease in arterial oxygen pressure (PaO2), peaking at 10 minutes (n = 10; mean age, 23.4 years). Morphine, 0.2 mg/kg intravenously also caused a significant decrease in PaO2 at 5 minutes (n = 10; mean age, 26.3 years). The combination of the same doses of morphine and secobarbital caused a significantly (P < .01) greater decrease in PaO2 at 5 and 10 minutes than the sole administration of either drug (n = 10; mean age, 23.5 years). Arterial oxygen pressure remained significantly (P < .05) reduced for 30 minutes. Although the PaCO2 increases after secobarbital and morphine did not reach statistical significance, their combination caused a significant (P < .05) increase in PaCO2. Both secobarbital and morphine alone caused significant (P < .05) decrease in pHa at 30 minutes. Their combination caused a significant (P < .01) reduction in pHa from 5 minutes until 60 minutes. In conclusion, both secobarbital and morphine alone caused ventilatory depression. The duration of ventilatory depression was greater with the intravenous combination than with either drug alone.
Zsigmond
E K
EK
Department of Anesthesiology, University of Illinois, Chicago.
Flynn
K
K
D000328:Adult; D002245:Carbon Dioxide / Q000097:blood*; D003864:Depression, Chemical; D004338:Drug Combinations; D006801:Humans; D009020:Morphine / Q000494:pharmacology*; D010100:Oxygen / Q000097:blood*; D012119:Respiration / Q000187:drug effects; D012631:Secobarbital / Q000494:pharmacology*
D004338:Drug Combinations; D002245:Carbon Dioxide; D012631:Secobarbital; D009020:Morphine; D010100:Oxygen