Canadian Journal of Anesthesia, Vol 12, 499-509, Copyright © 1965 by Canadian Anesthesiologists' Society

Double Blind Study of Hydroxyzine, Promethazine, Secobarbital, and a Placebo for Preanaesthetic Medication

¹ Department of Anesthesiology, State University Hospital, State University of New York, Upstate Medical Center, Syracuse, New York, 13210

A double–blind test was employed to compare the effect of three unknowns (hydroxyzine, secobarbital, and a placebo) with promethazine for pre–anaesthetic sedation on 373 adult patients who were being prepared for a major elective operation under general anaesthesia Each patient was given a capsule the night before, by mouth, and one hour before the operation the same compound was given intramuscularly, with scopolamine, to ensure an adequate antisialogogue effect and to help in preventing the identification of the sedative compound Data were collected on a special protocol which was completed for each patient by a nurse who was trained in this work The protocol contained information recorded from the initial pre–anaesthetic visit, before induction of anaesthesia (answers to direct questions by the patient), following induction of anaesthesia (answers to questions by the anaesthesiologist), and changes in vital signs and symptoms immediately after anaesthesia and during the first 24 hours after the anaesthetic Upon completion of the study, the data were tabulated and trans–ferred to IBM cards All data were then analyzed statistically by means of the chi–square test The analysis revealed that the patients seemed to feel better with hydroxyzine than with promethazine, secobarbital, or the placebo, in that order, whereas with the anaesthesiologist the order of preference was hydroxyzine, secobarbital, promethazine, and placebo. When the results were combined, the order preferred by the anaesthesiologist appeared to be the more valid.

None of the sedatives appeared to have an appreciable effect on the blood pressure or pulse rate before or after induction of anaesthesia, nor did the pre–medicant drugs appear to influence the incidence of postanaesthetic hypotension or nausea and vomiting On the other hand, amnesia occurred more frequently in the patients who received drugs for sedation, and the incidence of slow recovery from anaesthesia was significantly higher among these as compared to the patients who received the placebo The only other postoperative symptoms that might be related to the sedatives were the occurrence of shivering, which was highest among those patients who received secobarbital, and urinary retention (requiring catheterization), which occurred most often with those receiving promethazine.

Although the preferred order of the three sedatives and the placebo was statistically valid, the over–all differences were not great Only by careful documentation of the effects in a far larger series of patients will it be possible perhaps to obtain an unequivocal answer.