Intraoperative opiod analgesia for emergency obstetrics a comparison between pethidine and nalbuphine

Abstract

Pain relief in Emergency Operative Obstetrics under General Anaesthesia was studied in 300 patients at Kenyatta National Hospital. Three separate groups of 100 patients each differed only in the intraoperative analgesic component used.

Inclusion and Exclusion Criteria.

The patients were females between the ages of 15 and

45 years of A.S.A. classes I to III and were all in the first stage of labour scheduled for Emergency Caesarean Sections for a variety of reasons.

None of the patients had received any Opiods or Sedatives duri~g labour, or as part of the premedication. Those who had received the above drugs were excluded as were patients not in established labour, or those with evidence of any contraindicating Systemic diseases.

The basic Anaesthetic techniques were the same for the three groups, but only varied in the Intraoperative analgesic used, on clamping the umbilical cord. Patients in Group I received Pethidine (0.8 mg/kg). Patients in Group II received Nalbuphine (0.15 mg/kg). Patients in Group III (Controls) - No opiods used.

Pancuronium was used as the Non depolarising muscle relaxant and all patients received 67% Nitrous Oxide in Oxygen with 0.5% Halothane post delivery.

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The vital signs, Tidal and Minute Volumes, which had been measured preoperatively were again evaluated after the patients had regained consciousness fully. Patients were also questioned on the adequacy of pain relief according to the scale given (Appendix). Patients subjectively assessed the degree of analgesia. Any side effects such as sedation, vomiting or twitching were also noted. Patients were visited

in their Wards after 12 to 24 hours and questioned about any other side effects, intraoperative awareness, or recall. In addition the time of demand for postoperative analgesia was noted.

It was found that 34.7% of patients were in pain on awakening. However of these only 2% in Group I and 3% in Group II were not relieved of pain, whereas 99% of the Control group (Group III) were in pain; these patients were also the first to demand postoperative analgesia. In contrast patients in Groups I and II did not ask for analgesia for mean times of over two and a half hours postoperatively, and were generally calmer and less agitated.

As far as Ventilatory depression was concerned, all patients studied showed a decrease in both Tidal Volume and Minute Volume after operation. Group III (Control) patients showed the smallest depression with Groups I and II showing similar but larger degrees of depression.

Among side effects sedation was the most common but was not disturbing and patients were stable enough to go to the wards.

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Between the two groups studied Nalbuphine offered marginal advantages over Pethidine in the doses used. Although both drugs showed similar degrees of Analgesia and Ventilatory depression, Nalbuphine showed better Haemodynamic stability and less Nausea and Vomiting.