Biomedical subjects
I Power
Publications and source records attributed to I Power.
Effect of diclofenac on renal function and prostacyclin generation after surgery.
We have examined the effect of diclofenac on renal function after major surgery in a randomized, double-blind, controlled study of 20 patients undergoing oesophagogastrectomy. Diclofenac 75 mg or placebo was given i.m. 12-hourly for 2 days. I.v. fluid administration was standardized. Renal function was assessed by fluid balance and measurement of serum creatinine and electrolyte concentrations, creatinine and free water clearance, and urinary sodium and potassium excretion. Urinary 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) was measured by radioimmunoassay to assess renal prostacyclin production. After surgery, 6-keto-PGF1 alpha production increased, but this did not occur with diclofenac. On the first day after surgery, use of diclofenac was associated with a decreased urine flow rate, decreased urinary sodium and potassium excretion and a tendency to hyperkalaemia. Frusemide was required more often in the diclofenac group. One patient was withdrawn from the diclofenac group because of impaired renal function. Urine flow rate and blood potassium concentration should be monitored if diclofenac is used after major surgery.
Muscle damage with diclofenac injections.
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Addition of fentanyl to prilocaine for intravenous regional anaesthesia.
Fifteen volunteers underwent intravenous regional anaesthesia on two occasions using 40 ml 0.5% prilocaine, to which had been added either 2 ml 0.9% saline or 0.1 mg fentanyl (resultant concentration 2.5 micrograms/ml). There was no difference in the rate of onset of blockade of cold sensation from an ethyl chloride spray, or to sharp and touch pinprick sensation in either group. There was an increase in the incidence of nausea after tourniquet release in the fentanyl group. It is concluded that the addition of fentanyl 2.5 micrograms/ml to prilocaine 0.5% confers no benefit in intravenous regional anaesthesia.
Comparison of i.m. ketorolac trometamol and morphine sulphate for pain relief after cholecystectomy.
I.m. ketorolac trometamol 30 mg was compared with morphine sulphate 10 mg after cholecystectomy in a double-blind, multiple dose, randomized study of 100 patients. Assessments of pain were made immediately after operation (day 1), and the next morning (day 2). Pain intensity (verbal response score and visual analogue scale) was recorded before injection and then over a 6-h period. Pain relief was assessed also. The effect of ketorolac on operative blood loss and platelet function was examined. Time to commencing oral intake and the duration of administration of i.v. fluids were recorded. Adverse events were noted. Ketorolac produced significantly less analgesia than morphine on day 1, but on day 2 the two drugs produced a similar effect. Blood loss was not increased by ketorolac, although platelet function was impaired. Repeated i.m. administration of ketorolac did not produce any serious adverse effects.
Platelet function after intramuscular diclofenac.
A randomised double-blind controlled study was performed to examine the effect of diclofenac on skin bleeding time and in vitro whole blood platelet aggregation. Twenty thoracotomy patients were studied; 10 were given diclofenac 75 mg intramuscularly at induction of anaesthesia, and 10 formed a control group. Skin bleeding times and platelet aggregation tests were performed the day before and repeated one hour after induction of anaesthesia. Diclofenac prolonged skin bleeding time and reduced platelet aggregation. There were no significant changes in the control group.
The effect of fentanyl, meperidine and diamorphine on nerve conduction in vitro.
The effect of fentanyl, meperidine and diamorphine on A- and C-fiber conduction in an in vitro rabbit vagus nerve preparation was examined. The nerves were maintained at 37 degrees C with an oxygenated electrolyte solution. The effect of the commercial preparation of fentanyl (Sublimaze) and isotonic solutions of fentanyl, meperidine and diamorphine were observed. Sublimaze had a neurotoxic effect related to its hypotonicity. In isotonic solutions, fentanyl and meperidine, but not diamorphine, blocked nerve conduction and both showed marked frequency-dependent blocking actions in C-fibers. Naloxone (Narcan) did not prevent the effect of fentanyl. Both fentanyl and meperidine potentiated the block produced by a low concentration of bupivacaine (0.005 mM, 0.00016%), the effect of meperidine being seen at clinically relevant concentrations. Fentanyl was slightly more potent than meperidine in its effect on nerve conduction, but its greater opioid potency would not allow its use as a local anesthetic. The local anesthetic effect of meperidine may be more useful clinically.