Hypotension produced by the sympathetic blockade associated with spinal anesthesia has maternal and foetal adverse effects. Intravenous fluid expansion and vasopressors are used to prevent this hypotension. In this study we compared the effect of a combination of crystalloid co­load of lactated Ringer’s solution and a prophylactic phenylephrine infusion versus crystalloid coload alone in preventing predelivery hypotension in the mother following subarachnoid block for lower segment caesarean section. 100 ASA I or II term parturients posted for caesarean delivery were enrolled. They were randomly divided in to two groups: Group 1) a co­load of lactated Ringer’s solution at a volume of 15ml/kg body weight given over 10 minutes and a prophylactic phenylephrine infusion at rate of 50mcg/min. Group 2) a co­load of lactated Ringer’s solution at a volume of 15ml/kg body weight given over 10 minutes alone. Subarachanoid block was performed with 2 ml hyperbaric 0.5% bupivacaine (10 mg) at L3­4 interspace. Immediately after the injection of the intrathecal medication, the coload with or without infusion of phenylephrine was started depending on the group allocated. NIBP, heart rate and SpO2 were recorded every 1 minute until delivery, and thereafter every 3 minutes until the end of study. The incidence of pre­delivery hypotension was 2 % and 68 % respectively in group 1 and group 2. The lower incidence of pre­delivery hypotension in the group 1 was found to be statistically significant with a p value less than 0.01. The side effect profile of the two regimens was also comparable. In conclusion we found that prophylactic phenylephrine infusion at rate of 50mcg/min with a co­load of lactated Ringer’s solution at a volume of 15ml/kg body over 10 minutes significantly lowered predelivery hypotension in the mother. 

Keywords: Ringer Lactate Co­Load; Phenyephrine Infusion; Sub­Arachnoid Block; Hypotension.