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The direct application of preservative-free morphine sulfate (1.5%, 1 ml, 19.8 mumol) or fentanyl (0.06%, 1 ml, 1.07 mumol) on the superficial radial or saphenous nerve of cats did not alter the response of single C polymodal nociceptive fibers (PMNs) to noxious radiant heat stimulation of their peripheral receptive fields. Intravenous administration of fentanyl (100 or 200 micrograms/kg, 0.179 or 0.358 mumol/kg) also showed a similar lack of effect on the radiant heat evoked responses of single PMNs. Slight changes in the mean latencies following drug administration were recognized, which were not statistically significant. The use of morphine (1.5%, 1 ml, 19.8 mumol) with preservatives (chlorbutanol 0.5% and sodium bisulfite less than 0.1%) caused conduction block of PMNs within 6-15 min. Subsequent washout of the drug resulted in the return of the unitary discharges within 8 min. Lidocaine (0.25 and 0.5%, 10.7 mumol and 21.4 mumol) caused conduction block within 5-18 min. These data support the classically held concept that opiates, in clinically useful concentrations, do not alter peripheral nerve function.

Using small rabbit sino-atrial node preparations

Although a number of hemostatic drugs are currently used during surgery to reduce hemorrhage, their effects on bleeding are still controversial. Furthermore, few studies have been made on their prophylactic effects. The purpose of this study was to clarify the effects of hemostatic drugs on bleeding. Thirty adult patients undergoing upper abdominal surgery were randomly assigned to receive carbazochrome sodium sulfonate and tranexamic acid immediately after induction of anesthesia (group H,n=15) or no hemostatic drugs (group C,n=15). Common coagulation-tests [prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB)], thromboelastography [reaction time (R), coagulation time (K), maximum amplitude (MA), clot formation rate (α)], and determination of bleeding time were conducted before induction of anesthesia and just before the completion of surgery. PT, R, and K decreased significantly in both groups, while MA and α increased and FIB decreased significantly in group C. No significant difference in blood loss was observed between the groups. Our findings, therefore, suggest that these two hemostatic drugs do not have prophylactic effects on intraoperative bleeding. Further studies are, however, necessary before applying these results to all surgical patients.

No abstract