Norepinephrine versus Ephedrine to Maintain Arterial Blood Pressure during Spinal Anesthesia for Cesarean Delivery: A Prospective Double-blinded Trial.

BACKGROUND

Ephedrine was conventionally regarded as the first-choice drug to maintain maternal blood pressure during spinal anesthesia for cesarean delivery, due to its stimulant activity on α- and β-adrenergic receptors. Norepinephrine is a weak β-adrenergic and potent α-adrenergic receptor agonist. Therefore, it may be suitable for maintaining blood pressure with less chronotropic effects compared to ephedrine.

PATIENTS AND

METHODS

One hundred and forty healthy patients having cesarean delivery under spinal anesthesia were randomized to Group N (n = 61) who received a prophylactic bolus of norepinephrine 5 μg intravenous (i.v.) at the time of intrathecal block or Group E (n = 61) who received a prophylactic bolus of i.v. ephedrine 10 mg. Rescue i.v. bolus interventions of norepinephrine 5 μg or ephedrine 10 mg were given as required to maintain systolic blood pressure. Maternal and fetal hemodynamic variables, Apgar score, and number of boluses of vasopressors used were recorded.

RESULTS

The numbers of maternal hypotension and hypertension episodes and the frequency of bradycardia and tachycardia were significantly lower in Group N compared with Group E (P = 0.02, 0.003, 0.0002, and 0.008, respectively). The number of boluses of vasopressors used was also lower in Group N (P = 0.005). Uterine artery pulsatility index was lower in Group N compared to Group E (P = 0.01) when measured 5 min after spinal anesthesia. Moreover, it was higher at 5 min in Group E when compared with the baseline readings in the same group (P = 0.001).

CONCLUSIONS

Norepinephrine is a suitable and potent drug to counterbalance the hemodynamic effects of spinal anesthesia during cesarean delivery.