The influence of naloxone infusion on the action of intrathecal diamorphine: low-dose naloxone and neuroendocrine responses.

The influence of an intravenous infusion of naloxone 1 microgram kg-1 h-1, in combination with intrathecal diamorphine, on analgesia and hormonal stress responses after laminectomy was assessed in a blinded, randomized, placebo-controlled study. Twenty-seven patients undergoing laminectomy with postoperative analgesia provided by intrathecal diamorphine were investigated. Analgesia was reduced by naloxone (P less than 0.05), and the duration of analgesia was shortened by 180 min. The postoperative concentrations of both blood glucose and serum cortisol were reduced in the naloxone group compared to the control group (P less than 0.05). These results may indicate an excitatory role for the hypothalamic mu receptor in hypothalamo-pituitary-adrenocortical axis regulation.

Development of the Belfast orthopaedic information system.

A team from Musgrave Park Hospital, Belfast, describe their success in reducing the hip waiting list and introducing an information system to manage the orthopaedic waiting list.

Evaluation of anti-emetics in association with intrathecal diamorphine.

Intrathecal diamorphine is associated with a high incidence of emetic symptoms. Six anti-emetic drugs representing various chemical groups were given in random order to patients undergoing total hip replacement and who had received intrathecal diamorphine 0.5-1.0 mg. The phenothiazines, perphenazine and prochlorperazine, were more effective than the others. It is suggested that this might be a useful model for the evaluation of new anti-emetics.

Towards painless orthopaedic surgery.

Almost one thousand patients underwent either total hip replacement or spinal surgery in which diamorphine 0.5-1.0 mg was injected intrathecally. Approximately one half of the arthroplasty patients and one third of the spinal patients required no other post-operative analgesia. In the remainder, analgesics were not required for 12 hours post-operatively. The benefits of the technique and possible complications are discussed.

Postoperative analgesia in major orthopaedic surgery. Epidural and intrathecal opiates.

Sixty-two patients were given morphine 2 mg and 69 patients were given diamorphine 0.5 mg by either the epidural or intrathecal route. All had undergone either total hip replacement or spinal disc surgery. Forty-nine out of 131 patients required no further analgesia. Diamorphine was superior to morphine and the intrathecal route more effective than the epidural. Headache, pruritus, urinary retention and nausea and vomiting were recorded, the incidence of the latter being unacceptably high, particularly when the drugs were administered by the intrathecal route: one patient required resuscitation. It is suggested that previously reported respiratory depression using these techniques is associated with the administration of other analgesics contemporaneously; that dosage should be limited to one-fifth of the estimation intramuscular dose; and that patients should be observed in a recovery ward for 24 hours.

Pulmonary embolic syndrome caused by cementing of hip endoprosthesis.

Previous studies have indicated that cementing of the femoral component in total hip replacement produces the features of the pulmonary embolic syndrome (P.E.S.). The present investigations have been carried out to ascertain if newer methods of insertion modify these features. There was no evidence to suggest that any of these approaches has any advantage over the others in relation to the various components of P.E.S.

The effect of alcohol on the pulmonary embolic syndrome.

Total hip replacement surgery was carried out on 100 patients with an anaesthetic technique which was identical in all respects, except that fifty patients were given 5% dextrose while the other fifty received alcohol 0.5 mg/kg in addition. Patients were allocated to one or other group by random selection. There was no evidence that alcohol afforded any protection against the pulmonary embolic syndrome, nor did it appear to increase blood loss.

Intramedullary pressure patterns.

The insertion of cement and femoral prosthesis in total hip replacement produces biochemical abnormalities. These are thought to be caused by a marked rise in intramedullary pressure. Surgeons aim to reduce these pressures by using different methods of insertion and venting. The present investigation was undertaken to establish if any one method was superior to the others. The greatest modification of acrylic pressure was obtained by means of a drill hole. Thie highest rise in pressure was produced by the insertion of the femoral prosthesis and this was little modified by any of the alternatives of the use of a 3/16 inch drill hole, a 16-gauge catheter, and cement gun.

Biochemical disturbances associated with total hip replacement.

A prospective study on 227 patients undergoing arthroplasty of the hip was carried out with reference to the effects on the cardiovascular and respiratory systems. Investigations revealed that the placing of acrylic bone cement and the prosthesis in the femoral shaft produced clinical and biochemical disturbances which were consistent with pulmonary microembolism. A fall in arterial oxygen tension during the procedure and hypoxaemia extending into the postoperative period with elevation of serum lipase and a fall in triglycerides supported the idea that embolisation with marrow fat occurred. The method of venting (by catheter or proximal hole) did not influence the biochemical disturbances. The implications of these findings are discussed.

Clinical considerations in anaesthesia for hip arthroplasty.

Experiences with the anaesthetic management of 248 patients undergoing total hip replacement are presented. Blood loss does not appear to be influenced by hypertension, the method of venting or the type of anaesthetic, with the exception of neurolept-analgesia. The importance of oxygen therapy in the treatment of the pulmonary embolic syndrome is stressed and the prevention of deep venous thrombosis is discussed. Mortality and morbidity figures are given.