Supplementation of general anaesthesia with tramadol or fentanyl in parturients undergoing elective Caesarean section

Purpose: Tramadol has been recommended for analgesia in parturients undergoing vaginal delivery. The present report investigated the effect of tramadol versus fentanyl on umbilical vein (UV) blood gases and Apgar scores of neonates delivered via elective Caesarean section under general anaesthesia. Methods: Forty ASA I or II parturients undergoing elective Caesarean section were included in a randomized double-blinded study. The patients were divided into a tramadol (n = 20) and fentanyl groups (n = 20). During preoxygenation, one group received 100 mg tramadol iv, while the second received 100 mu g fentanyl. Anaesthesia was induced in both groups by 3 mg.kg(-1) thiopentone and 1.5 mg.kg(-1) succinylcholine was given to facilitate tracheal intubation. Anaesthesia was maintained during the induction-delivery period with nitrous oxide 50% in oxygen. Results: The umbilical vein PO2 was higher in the fentanyl (34 +/- 5 mmHg) than in the tramadol group (24 +/- 6 mmHg) (P < 0.01), while the UV PCO2 was higher in the tramadol group (50 +/- 5 vs 45 +/- 4 mmHg) (P < 0.01). The Apgar scores at one and five minutes were not different between the two groups. Post operatively, two patients in the tramadol group recalled the crying of their newborn at delivery. Conclusion: Tramadol is associated with a high incidence of intraoperative maternal recall and can result in lower umbilical vein PO2 and higher PCO2 than in the fentanyl group.