Apoorva Singh1, Kajal Jain, Nitika Goel, Aashima Arora, Praveen Kumar. 1. From the Department of Anesthesia and Intensive Care (AS, KJ, NG), Department of Obstetrics and Gynecology (AA) and Department of Neonatology, PGIMER, Chandigarh, India (PK).
Abstract
BACKGROUND: There is limited evidence to support the use of noradrenaline over phenylephrine during elective caesarean section with regards to its impact on foetal acidosis. Concerns regarding a deleterious effect of noradrenaline on foetal blood gas analysis because of its β-mimetic activity cannot currently be ruled out by data from randomised controlled trials. OBJECTIVE: We hypothesised that noradrenaline would be associated with higher umbilical artery base excess values and less foetal acidosis compared with phenylephrine. This study aimed to observe the effect of prophylactic infusions of phenylephrine or noradrenaline in low-risk elective caesarean delivery on umbilical artery blood gas analysis. DESIGN: A prospective, randomised, double-blind trial. SETTING: Labour room operating theatre of tertiary care hospital in Northern India from April 2020 to November 2020. PATIENTS: Full-term, nonlabouring pregnant women, scheduled for elective caesarean delivery under spinal anaesthesia. INTERVENTION: Equipotent prophylactic infusions of either phenylephrine 100 μg min-1 or noradrenaline 5 μg min-1 were administered to maintain maternal SBP between 90 and 110% of baseline using a predefined algorithm. MAIN OUTCOME MEASURE: The primary outcome was umbilical artery base excess in noradrenaline versus the phenylephrine group. The incidence of foetal acidosis defined as umbilical artery base excess less than -6 mmol l-1 was also assessed for noradrenaline versus phenylephrine. RESULTS: Median [IQR] umbilical artery base excess was significantly higher in the noradrenaline group: -5.4 [-6.6 to -4.03] versus -6.95 [-9.02 to -4.53] in the phenylephrine group (P = 0.014). No significant difference in the incidence of foetal acidosis was observed between noradrenaline and phenylephrine groups: 36 versus 54% (P 0.07); difference 18% (95% CI, -1.4 to 35.6%). CONCLUSION: Prophylactic noradrenaline 5 μg min-1 infusion resulted in higher base excess values compared with phenylephrine 100 μg min-1 infusion. A comparable incidence of foetal acidosis was observed in women receiving either noradrenaline or phenylephrine. Maternal bradycardia was more pronounced with phenylephrine while targeting blood pressure goals. CTRI: CTRI/2020/03/023986.
BACKGROUND: There is limited evidence to support the use of noradrenaline over phenylephrine during elective caesarean section with regards to its impact on foetal acidosis. Concerns regarding a deleterious effect of noradrenaline on foetal blood gas analysis because of its β-mimetic activity cannot currently be ruled out by data from randomised controlled trials. OBJECTIVE: We hypothesised that noradrenaline would be associated with higher umbilical artery base excess values and less foetal acidosis compared with phenylephrine. This study aimed to observe the effect of prophylactic infusions of phenylephrine or noradrenaline in low-risk elective caesarean delivery on umbilical artery blood gas analysis. DESIGN: A prospective, randomised, double-blind trial. SETTING: Labour room operating theatre of tertiary care hospital in Northern India from April 2020 to November 2020. PATIENTS: Full-term, nonlabouring pregnant women, scheduled for elective caesarean delivery under spinal anaesthesia. INTERVENTION: Equipotent prophylactic infusions of either phenylephrine 100 μg min-1 or noradrenaline 5 μg min-1 were administered to maintain maternal SBP between 90 and 110% of baseline using a predefined algorithm. MAIN OUTCOME MEASURE: The primary outcome was umbilical artery base excess in noradrenaline versus the phenylephrine group. The incidence of foetal acidosis defined as umbilical artery base excess less than -6 mmol l-1 was also assessed for noradrenaline versus phenylephrine. RESULTS: Median [IQR] umbilical artery base excess was significantly higher in the noradrenaline group: -5.4 [-6.6 to -4.03] versus -6.95 [-9.02 to -4.53] in the phenylephrine group (P = 0.014). No significant difference in the incidence of foetal acidosis was observed between noradrenaline and phenylephrine groups: 36 versus 54% (P 0.07); difference 18% (95% CI, -1.4 to 35.6%). CONCLUSION: Prophylactic noradrenaline 5 μg min-1 infusion resulted in higher base excess values compared with phenylephrine 100 μg min-1 infusion. A comparable incidence of foetal acidosis was observed in women receiving either noradrenaline or phenylephrine. Maternal bradycardia was more pronounced with phenylephrine while targeting blood pressure goals. CTRI: CTRI/2020/03/023986.