Two Norepinephrine Rescue Bolus Doses for Management of Severe Post-spinal Hypotension During Elective Cesarean Delivery

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Maternal hypotension after spinal block is a common complication after subarachnoid block in this population whose incidence reached 60% in many reports. Hypotension is associated with maternal and neonatal complications; therefore, it is highly recommended to use vasopressors, prophylactically and interactively, for prompt control maternal blood pressure. Despite the presence of various preventive regimens (fluid loading, maternal positioning, and vasopressors), many mothers develop intraoperative episodes of hypotension which requires the use of a vasopressor bolus. Norepinephrine (NE) is an alpha adrenergic agonist with weak beta adrenergic agonistic activity; and is increasingly used in obstetric anesthesia with acceptable maternal and neonatal outcomes. NE bolus could be used for rapid correction of maternal blood pressure in a dose which variedranged between 3.7-10 mcg. Till date, al the available data for the management of maternal hypotension did not differentiate between severe and non-severe hypotension. The incidence of severe maternal hypotension (systolic blood pressure ≤60% of baseline) ranged between 7-20%. In a recent report, Hassabelnaby et al compared 6 mcg and 10 mcg NE boluses in management of maternal hypotension and found that the doses had the same success rate (≈90%); however, most of the participants in the mentioned study had non-severe hypotension. Therefore, we hypothesize that severe hypotension should be separately investigated for the possible superiority of the higher over the lower dose of NE bolus. Insufficient NE bolus would lead to failed management and prolonged hypotensive episode, whereas a higher dose might lead to reactive hypertension and/or bradycardia, which is sometimes severe. Therefore, determining the optimum dose for NE bolus would enable proper control of maternal hemodynamic profile

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