Supplemental oxygen for caesarean section under spinal anaesthesia.

BACKGROUND Routine administration of supplemental oxygen to parturients undergoing Caesarean section under spinal anaesthesia has been criticised in recent times. OBJECTIVES To assess the need for routine supplementary oxygen in healthy women undergoing Caesarean section under spinal anaesthesia in resource challenged setting and establish the efficacy of administration of oxygen at 4L/min. DESIGN Simple randomized trial using sealed envelopes. SETTING The Obafemi Awolowo University Teaching Hospital; a 580 bed hospital situated in Ile-Ife in South-western Nigeria. SUBJECTS Seventy parturients with ASA physical status I or II undergoing Caesarean section under spinal anaesthesia. MAIN OUTCOME MEASURES Outcome measures were arterial oxygen saturation (SaO2) and Apgar scores at one and five minutes. RESULTS The mean pre-induction arterial oxygen saturation in the two groups were similar. There was a statistically significant difference in the mean SaO2 at one minute between the two groups, with the control group being higher (97.7% +/- 1.5% versus. 96.7% +/- 1.5%; p-value = 0.008). The mean least SaO2 during surgery was also higher in the control group (95.9% +/- 1.5% versus 94.9% +/- 2.0%, p-value = 0.015). The Apgar score of the babies at one and five minutes for the study and control group were similar. CONCLUSION Healthy parturients undergoing Caesarean section under spinal anaesthesia do well without supplemental oxygen; administration of supplemental oxygen from the common gas outlet of anaesthetic machine with the breathing circuit and standard anaesthetic facemask at 4L/min causes relative desaturation.