The premedication of cardiac surgical patients. A clinical comparison of four regimes.

One of four groups of patients was not premedicated; the others received diazepam 10 mg by mouth, diazepam 20 mg by mouth or a combination of pentobarbitone orally and morphine and hyoscine intramuscularly. The cardiovascular and respiratory parameters were studied before and after the premedication and any changes in sedation, apprehension and reaction to pain were noted. The ease of induction of anaesthesia in the four groups was compared. Most of the patients who received the pentobarbitone, morphine and hyoscine combination came to theatre calm, sedated and often asleep. They showed no significant cardiovascular or respiratory depression and the induction of anaesthesia was more satisfactory than in the other groups. Two of the patients who were not premedicated became very agitated in the ward and the remainder of the patients in this group were apprehensive in the anaesthetic room and during induction. The effects of diazepam in the two doses studied were intermediate between those who received the pentobarbitone, morphine and hyoscine and those who were not premedicated.