The effect of 10° head‐up tilt in the right lateral position on the systemic blood pressure after subarachnoid block for Caesarean section

Abstract

SummaryForty women presenting for elective Caesarean section under spinal anaesthesia were randomly assigned to have anaesthesia induced in the right lateral position either in the horizontal position or with 108 head-up tilt. Hyperbaric bupivacaine 2 ml 0.5% with 0.1 mg of morphine was injected intrathecally before the parturients were placed in the supine position with 158 left lateral tilt. Blood pressure and heart rate were monitored every minute and the sensory level (loss of sharp sensation to pinprick) was monitored every 3 min until clamping of the umbilical cord. Ephedrine 6 mg was given every minute that the systolic blood pressure decreased below 90 mmHg. The mean systolic blood pressure during the first 5 min after induction of spinal anaesthesia was lower in the control group compared to the tilted group (99 mmHg vs. 109 mmHg; p 0.043). The upper limit of block was higher in the control group compared to the tilted group (p 0.002). The use of 108 head-up tilt resulted in a reduced incidence of hypotension initially and less extensive sensory block.

Ultra-low dose combined spinal-epidural anesthesia with intrathecal bupivacaine 3.75 mg for cesarean delivery: a randomized controlled trial

“…Sample size was computed to detect a 45% absolute reduction in the study group, from a previously reported 85% incidence in our institution. 7 Assuming a = 0.05, b = 0.2 (i.e. 80% power), it would require 21 patients per group to show this.…”

Effects of sitting up for five minutes versus immediately lying down after spinal anesthesia for Cesarean delivery on fluid and ephedrine requirement; a randomized trial

“…6 In contrast, patient position has had variable effects on the incidence of hypotension after spinal anesthesia. [7][8][9][10] In addition, in trials evaluating the effects of patient position on blood pressure changes, there have been studies of the administration of spinal anesthetic in the sitting position (followed immediately by placing the patient in the supine or lateral position) 11 or in the lateral position (followed by either turning the patient supine or keeping the patient in the lateral position). 12 Sitting the patient up for three minutes after spinal anesthesia has not been found to reduce the occurrence of hypotension.…”

Intrathecal drug spread

“…The maintenance of 10 or so of head-up tilt reduces spread, 80 but also has two potentially adverse effects. First, the block may not spread far enough for the projected surgery.…”

“…First, the block may not spread far enough for the projected surgery. 80 Second, there is again the risk of peripheral pooling of venous blood causing serious hypotension. In fact, every authority on spinal anaesthesia from the time of Labat has recommended the reverse: a small degree of head down tilt to ensure venous return, thereby maintaining cardiac output and blood pressure.…”