Postoperative analgesic requirements in patients exposed to positive intraoperative suggestions.

OBJECTIVE: To establish whether positive suggestions given to a patient under general anaesthesia reduce postoperative pain and analgesic requirements. DESIGN: Prospective double blind randomised study. SETTING: Operating theatre and gynaecology ward of a teaching hospital. PATIENTS: 63 Woman undergoing elective abdominal hysterectomy were randomised to be played either a tape of positive suggestions or a blank tape during the operation through a personal stereo system. INTERVENTIONS: Three women were withdrawn from the study. Anaesthesia was standardised for all of the women. Postoperative analgesia was provided through a patient controlled analgesia system for the first 24 hours. Pain scores were recorded every six hours. MAIN OUTCOME MEASURES: Morphine consumption over the first 24 hours after the operation; pain scores. RESULTS: Mean morphine requirements were 51.0 mg (95% confidence interval 42.1 to 60.0 mg in the women played positive suggestions; and 65.7 mg (55.6 to 75.7 mg) in those played a blank tape. The point estimate (95% confidence interval) for the difference of means was 14.6 mg (22.4%) (1.9 (2.9%) to 27.3 mg (41.6%] (p = 0.028). Pain scores were similar in the two groups. CONCLUSION: Positive intraoperative suggestions seem to have a significant effect in reducing patients' morphine requirements in the early postoperative period.

The influence of patient characteristics on the requirements for postoperative analgesia. A reassessment using patient-controlled analgesia.

The requirements for analgesia after upper abdominal surgery were evaluated in 100 patients who received morphine by way of a patient-controlled analgesia system. Hourly and cumulative 24-hour requirements were analysed for possible correlations with patient characteristics and for the patterns of consumption throughout the 24-hour study period. The level of pain relief was assessed by linear analogue pain scores at 4-6 hours and 24 hours. Male patients (n = 46) required significantly more morphine than female patients (n = 54) to achieve similar levels of pain relief (p less than 0.05). There was an inverse correlation between age and morphine consumption in both males and females (r = -0.684, p less than 0.00005 and r = -0.502, p less than 0.00005 respectively). No correlation was found between morphine consumption and patient weight. The pattern of hourly morphine consumption appeared to follow a diurnal rhythm, with peak times of demand at 0900 and 2000 hours. The variations in requirements for analgesia among patients and with time of day should be taken into account when a regimen for postoperative analgesia is prescribed.

Assessment of the analgesic efficacy of nefopam hydrochloride after upper abdominal surgery: a study using patient controlled analgesia.

A randomized, double-blind, placebo-controlled study was performed to assess the analgesic efficacy of intramuscular nefopam hydrochloride after upper abdominal surgery. Patients received either 20 mg nefopam (n = 23) or matching placebo (n = 26), 90 min before surgery, immediately after surgery, and 6, 12 and 18 h after the end of surgery. The 24-h morphine requirements were measured using a patient-controlled analgesia system delivering on-demand intravenous bolus doses of morphine. Pain was assessed using visual analogue scales. Patients receiving nefopam had a mean (+/- s.e.m.) cumulative morphine consumption of 4.1 +/- 0.8 mg in the first hour, compared with 8.5 +/- 0.8 mg in the control group (P less than 0.01). After 24 h the consumptions were 44.1 +/- 7.2 mg and 62.5 +/- 6.9 mg respectively (P less than 0.05). The pain scores in both groups were similar. This study confirms that nefopam hydrochloride has significant analgesic effects and would be a useful supplement to morphine in the management of postoperative pain.