Wound instillation for postoperative pain relief: a comparison between bupivacaine and saline in patients undergoing aortic surgery.

In a double blind trial 72 patients having elective aortic surgery were randomized to receive either 40 ml of 0.25% bupivacaine or 40 ml of saline through one or two indwelling wound irrigation catheters every four hours over a total of 48 hours. In transverse incisions the two catheters were randomly placed either subcutaneously or in the rectus sheath; in vertical incisions one catheter was placed subcutaneously. Analgesia was assessed by visual analogue score on Postoperative Days 1 and 2 and the number of doses of intramuscular morphine given during the instillation period. Pulmonary function was monitored by forced expiratory volume and peak flow on Postoperative Days 1 to 5; arterial blood gases were monitored preoperatively and Postoperative Day 2. In all parameters evaluated there was no statistically significant difference between the saline (n = 33) or the bupivacaine (n = 37) groups. Site of the catheter in the transverse groups made no difference. Comparing vertical (n = 21) and transverse (n = 49) incisions, the mean visual analogue scores on the first postoperative day were 40 and 29, respectively (p less than 0.05). Wound instillation with bupivacaine neither improves pulmonary function nor reduces morphine requirements when compared to saline. Transverse incisions may be less painful than vertical ones.

Modification by alfentanil of the haemodynamic response to tracheal intubation in elderly patients. A dose-response study.

Fifty-five elderly patients undergoing elective ophthalmological surgery were randomly allocated to four groups. Following the induction of anaesthesia with thiopentone (given over 2 min) and the administration of atracurium 0.6 mg kg-1, patients received alfentanil 400, 600, 800 or 1000 micrograms. Intubation of the trachea was performed 90 s later. Heart rate was monitored continuously and systolic arterial pressure was measured at 1-min intervals for 3 min before induction, and both variables were monitored until 10 min had elapsed after tracheal intubation. In each of the groups there was a significant decrease in systolic arterial pressure and a significant increase in heart rate on induction of anaesthesia. In those patients who received either 400 or 600 micrograms of alfentanil, arterial pressure increased immediately after tracheal intubation, whereas in those receiving alfentanil 800 or 1000 micrograms, arterial pressure decreased immediately after tracheal intubation, and when measured 10 min after intubation. It is suggested that alfentanil 600 micrograms (10 micrograms kg-1) constitutes the optimal dose with which to obtund the haemodynamic response to tracheal intubation in elderly patients, and to minimize cardiovascular depression after tracheal intubation.

The pharmacokinetics and clinical effects of a low dose of alfentanil in elderly patients.

Alfentanil is a potent short-acting opioid analgesic which depresses respiration and can cause cardiovascular depression. The elderly can show greater sensitivity to opioid drugs which may be related to pharmacokinetic differences. The pharmacokinetics and clinical effects of alfentanil were studied in 10 elderly patients aged 68-86 years who were undergoing cystoscopy or urethrotomy under general anesthesia. After induction with thiopentone, and while the patient was breathing nitrous oxide with halothane 0.5% (enflurane 1.0% was given to one patient), a dose of alfentanil 4 micrograms/kg was given 15, 20, 30, 45 and 60 minutes after the alfentanil administration, and then every 30 minutes for 6 hours. Pulse rate (PR), systolic blood pressure (SBP), and minute volume (MV, calculated from the respiratory rate and the tidal volume) were measured at 1, 3, 5, 7 and 9 minutes after the alfentanil injection. Pharmacokinetic analysis showed Vc 82 (+/- S.D. 26) ml/kg; VDSS 277 (+/- S.D. 71) ml/kg; clearance 2.01 (+/- S.D. 0.64) ml/kg/min; t1/2 beta 117 (+/- S.D. 24) min. Comparison of these results with the results of other studies supports the view that older patients eliminate alfentanil less rapidly than younger patients, with prolongation of t1/2 beta and decreased clearance. The clinical results showed a decrease in minute volume from a mean value of 5944 ml before alfentanil to 1240 ml 1 minute after alfentanil (P less than 0.001). The minute volume was still significantly lower at 3 and 5 minutes, but had returned to the pre-alfentanil value by 7 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Aspects of anaesthesia in the elderly.

Many anaesthetists find themselves spending an increasing amount of time in the perioperative care of patients more than 65 years old. This article considers some aspects of anaesthesia for these patients which will help to ensure safe anaesthesia.

A review of methods for relief of postoperative pain.

Methods available for the relief of postoperative pain are reviewed. The use of intermittent injections of morphine is likely to remain the established method and suggestions are made for its more effective use. Newer methods are discussed in terms of their expense and the effects on medical and nursing workload. It is suggested that nurses trained in pain relief methods could greatly improve the relief of pain following operation.

Postoperative effects of methylphenidate.

A double-blind study is described in which the analgesic and analeptic properties of methylphenidate were investigated in 63 patients following surgery. No effect of methylphenidate on postoperative pain was observed. However, methylphenidate reduced sedation up to 30 min after operation, and improved respiratory function up to 180 min in patients receiving halothane. No conclusive evidence of improvement in mood was obtained, and occasional undesirable behavioural effects of methylphenidate were seen.

Respiratory and psychological effects of oral temazepam in volunteers.

In a double-blind comparison with placebo the time-course of the effects of temazepam 40 mg and 20 mg on breathing, arterial pressure, oral temperature, cognitive function, psychomotor performance and subjective observations have been examined in 12 healthy volunteers. Temazepam 40 mg caused significant displacement of the ventilatory response to carbon dioxide 1 h after administration and a decrease in oral temperature 2 h after administration. Deficits in cognitive function were still apparent 1.5 and 2.5 h after administration and psychomotor performance did not equal control at 3.5 h. However, most subjects felt normal 2.5-3 h afterwards. Temazepam 20 mg had significant effects on cognitive function and psychomotor performance only during the 1st hour after administration.

Comparative study of two long-acting tranquillizers for oral premedication.

Lorazepam 2.5 mg was compared with promethazine 50 mg as oral premedication in a double-blind study in women. The premedication was given at the same time to all patients on each operating list, and both drugs continued to be effective 6 h after ingestion. A similar number of patients considered each drug to have relieved anxiety and the amnesic effect of lorazepam was confirmed. However, the use of lorazepam alone was accompanied by significantly more salivation during and after anaesthesia than the use of promethazine, especially in patients in whom the trachea was intubated. There was also a higher frequency of vomiting during and after operation with lorazepam (seven of 67 patients) than after promethazine (one of 71 patients). Promethazine produced dyskinetic side-effects in six of 71 patients.