Marc Dejonckheere

Antiemetic Effect of Subhypnotic Doses of Propofol After Thyroidectomy

Postoperative nausea and vomiting (PONV) are unpleasant, often underestimated side effects of anaesthesia and surgery, not devoid of medical complications. Prevention with antiemetics is only partially effective. Propofol has been shown recently to possess antiemetic properties in several situations. In this prospective, randomized, controlled trial, we have compared the antiemetic efficacy of subhypnotic doses of propofol, with Intralipid as placebo, after thyroidectomy. We studied 64 patients of both sexes, aged 22-71 yr, ASA I or II, undergoing thyroidectomy. After premedication with a benzodiazepine, balanced anaesthesia was produced with isoflurane and nitrous oxide in oxygen, and supplementary analgesia with fentanyl i.v. as required. Postoperative analgesia was provided with non-opioids, and piritramide 0.25 mg kg-1 i.m. on demand. Patients were allocated randomly and blindly to receive a 20-h infusion of either propofol or 10% Intralipid 0.1 ml kg-1 h-1. Intralipid, the excipient of propofol, was chosen as placebo as it is devoid of antiemetic effects. Sedation scores, respiratory and cardiovascular variables, and incidence of PONV were assessed every 4 h for 24 h. Pulse oximetry and ECG were monitored continuously. Both groups were comparable in characteristics, surgical and anaesthesia procedures, amount of opioids given during and after operation, and total amount of the study drug infused after operation. Occurrence of PONV was similar before the start (propofol 41%, Intralipid 50%) and after completion (propofol 0.64%, Intralipid 1.6%) of infusion and decreased with time in both groups during the infusion. However, symptoms were reduced to nil with propofol but persisted and were more severe with Intralipid during infusion (P < or = 0.01). The overall incidence of PONV during infusion was 10% (three of 32 patients) in the propofol group and 65% (21 of 32 patients) in the Intralipid group. Cardiovascular and respiratory variables, and SpO2 were unaltered, and sedation decreased similarly with time in both groups. We conclude that propofol, given at subhypnotic doses, effectively reduced the incidence of PONV without untoward sedative or cardiovascular effects.

INTRAVENOUS TRAMADOL COMPARED TO PROPACETAMOL FOR POSTOPERATIVE ANALGESIA FOLLOWING THYROIDECTOMY

We compared the efficacy and side effects of propacetamol (P), an injectable prodrug of acetaminophen, 2 g and tramadol (T), a weak synthetic opioid, 1.5 mg.kg-1, given intravenously following thyroidectomy. 80 patients were randomly assigned to blindly receive one dose of P or T on request in the PACU. Residual pain was treated with i.v. PCA morphine. Pain and patient satisfaction were assessed with Visual Analog Scales. Demographic and peroperative data were comparable in both groups. Although the morphine consumption was comparable (p = 0.71), the decrease in VAS pain scores was significantly higher following tramadol (p = 0.03). More patients complained of nausea and vomiting (p = 0.01) during the first two hours following injection of tramadol, but there was no difference throughout the whole study. Oversedation was not observed in any group. We conclude that a single dose of tramadol provides a better quality of analgesia than propacetamol during the first six hours after thyroidectomy, but fails to ensure optimal analgesia, since VAS pain scores failed to fall below 3 despite the use of supplemental morphine.