Aortocaval compression (ACC) by the gravid uterus is a known physiological phenomenon that is classically claimed to cause supine hypotension in full term pregnant women. ACC has been also mentioned as a possible cause of post-spinal hypotension (PSH) in parturients undergoing cesarean section (CS); however, the evidence for the value of left lateral tilting of parturient in improving hemodynamics is not clear.~The aim of this work is to investigate the effect of different angles of lateral tilt on the maternal hemodynamics before and after subarachnoid block (SAB).~Hemodynamic variables will be taken before SAB in three angles (zero angle, 15 degree angle, and 30 degree angles) of left lateral tilt.~Patients will receive normal SAB after prophylactic vasopressor adminstration (either 15 mg ephedrine or 1.5 mcg/Kg phenylephrine intravenous bolus) then hemodynamic variables will measured again after SAB in the same three angles. The sequence of the tilting angles will be randomized.~Another measure will be taken after delivery of the fetus. SAB will be done in sitting position under complete asepsis using 25 g spinal needle with crystalloid infusion of 500 mL. SAB will be achieved by intrathecal injection of 10 mg hyperbaric Bupivacaine plus 25ug fentanyl. Success of SAB will be tested within five minutes after drug injection. SAB will be considered successful if adequate block reached T4 dermatome.~Cardiac output and stroke volume will be measured using electrical cardiometry device.
The aim of this work is to investigate the effect of different angles of lateral tilt on the maternal hemodynamics before and after subarachnoid block