Summary

Background and objective: The incidence of pain associated with the injection of propofol still remains a problem. This study sought to examine the analgesic effects of inhaled nitrous oxide in oxygen on the prevention of propofol injection pain.

Methods: Nitrous oxide in oxygen was compared with a lidocaine (20 mg)–propofol mixture and with propofol alone (control) in a prospective, randomized, observer-blinded study. ASA I and II patients (n = 135) scheduled for elective surgical procedures were studied. A standard propofol injection technique and scoring system to measure the pain on injection was used.

Results: Demographic variables were similar between the study groups. Without analgesia (control) 26 of 45 patients (58%) reported pain on injection compared with 11 of 45 patients (24%) in both the nitrous oxide (95% CI: 14–52%, P = 0.001) and lidocaine groups (95% CI: 14–52%, P = 0.001).

Conclusions: The inhalation of a nitrous oxide/oxygen mixture significantly reduces the incidence of pain during propofol injection. This therapeutic stratagem was as effective as a lidocaine–propofol mixture.

Summary

Background and objective: To compare the antiemetic efficacy of ondansetron with two different hypnotic drugs (propofol 15 mg, midazolam 1 and 2 mg) for the treatment of established postoperative nausea and vomiting (PONV).

Methods: Four-hundred-and-fifty-three patients scheduled for elective gynaecological or abdominal surgery were enrolled. One-hundred-and-twenty patients (26%) experienced postoperative emesis, and when nausea scores reached 2 or greater on a five-point scale, they were randomized to receive intravenously: propofol 15 mg (1.5 mL) in Group P, midazolam 1 mg in Group M1, midazolam 2 mg in Group M2 and ondansetron 4 mg in Group O.

Results: Four patients (13.3%) in Group P, 13 patients (43.3%) in Group M1, five patients (16.6%) in Group M2 and one patient (3.3%) in Group O required a second dose of the study drug. After administration of the study drugs, nausea scores were significantly lower in all groups than before these drugs were given. No patient had a sedation score over 3 (the patients remained awake and/or responded to verbal contact). The sedative effects of midazolam and propofol lasted for a much shorter time than the antiemetic effects of these drugs.

Conclusions: Propofol and midazolam used in subhypnotic doses were as effective as ondansetron in treating PONV in patients undergoing abdominal or gynaecological surgery without untoward sedative or cardiovascular effects.