Anti-emetic effect of midazolam added to morphine patient-controlled analgesia after total abdominal hysterectomy.

Nausea and vomiting are frequent adverse effects of patient-controlled analgesia with opioids. This study was designed to compare the effect of midazolam to that of ondansetron for prevention of nausea and vomiting during morphine patient-controlled analgesia. In a randomised, double-blind, prospective trial, 90 patients were allocated to one of three groups of 30 each, to receive one of three patient-controlled analgesia regimens to manage postoperative pain: a combination of midazolam and morphine (group M), a mixture of ondansetron and morphine (group O) or morphine alone (group C). Patients were assessed for the incidence of nausea and vomiting, the degree of sedation (awake, mild, moderate, deep) and other side-effects during the first 24 hours after the operation. The frequency of nausea and vomiting was significantly lower in groups M (27%) and O (37%) compared with group C (70%) (P < 0.05). The incidence of mild sedation in group M was significantly higher than that in groups O or C (P < 0.05). We conclude that midazolam is as effective as ondansetron in preventing opioid-induced nausea and vomiting following total abdominal hysterectomy and has acceptable side-effects.

Pre-medication with intravenous clonidine suppresses fentanyl-induced cough.

BACKGROUND: A reflex cough is often observed after an intravenous bolus of fentanyl. This study was conducted to determine whether pre-treatment with intravenous clonidine could effectively attenuate fentanyl-induced cough. METHODS: Three hundred ASA I-II patients, aged between 18 and 80 years, undergoing various elective surgeries, were enrolled in this study. All patients were randomly assigned to one of two groups treated with intravenous clonidine 2 microg/kg (clonidine group) or the same volume of normal saline (control group). Intravenous fentanyl (2 microg/kg in 2 s) was injected 2 min after the clonidine or normal saline injection. Changes in the hemodynamics, auditory evoked potentials (AEPs) and Observer Assessment of Alertness/Sedation (OAA/S) rating scale were recorded before and 2 min after the clonidine or normal saline injection and 1 min after the fentanyl injection. The number of coughs 1 min after the fentanyl injection was also recorded. RESULTS: Patients in the clonidine group showed a significantly lower incidence of cough than those in the control group (17.3% vs. 38.7%, respectively; P < 0.01). The blood pressure was lower in the clonidine group than in the control group. There were no significant differences in AEP or OAA/S rating scale. CONCLUSIONS: Pre-treatment with intravenous clonidine (2 microg/kg) suppressed the reflex cough induced by fentanyl, with mild hemodynamic changes. Therefore, intravenous clonidine may be a clinically useful method of suppressing fentanyl-induced cough.