Effect of Different Positions During Surgical Preparation With Combined Spinal-Epidural Anesthesia for Elective Cesarean Delivery: A Randomized Controlled Trial

Abstract

BACKGROUND: The intraoperative 15° left-tilt position during cesarean delivery has more recently been questioned regarding its effect on fetal acid-base balance and is a frequent source of complaints by surgeons. We hypothesized that a 30° left-tilt position during surgical preparation could improve the acid-base balance of the fetus compared with the 15° left-tilt or supine position during surgical preparation. METHODS: Women undergoing elective cesarean delivery under combined spinal epidural anesthesia were randomized to a supine position, 15° left-lateral tilt position or 30° left-lateral tilt position; the position was changed to supine before the incision. Anesthetic management was standardized and included fluid loading with 10 mL/kg of normal saline followed by colloid loading. Hypotension (systolic blood pressure [SBP] reduction >20% baseline value or SBP <90 mm Hg) was treated with boluses of phenylephrine or ephedrine according to maternal heart rate. The primary outcome was umbilical arterial blood pH and the secondary outcomes included maternal SBP within 15 minutes after induction of anesthesia, the amount of vasoactive drug administered before end of the surgery, and the incidence of hypotension during cesarean delivery. RESULTS: Seventy-five patients were included. After testing by analysis of variance, there was no significant difference in the umbilical arterial pH among the 3 groups (supine group: 7.31 ± 0.03 vs 15° group: 7.30 ± 0.04 vs 30° group: 7.31 ± 0.02, P = .28). The 30° group required significantly less phenylephrine (P = .007) and ephedrine (P = .005) before the end of surgery than the supine group; however, the only benefit observed in the 15° group was that the mean SBP at 3 minutes after spinal injection was significantly improved compared with the supine group. CONCLUSIONS: Compared with the supine position, the 30° left-tilt position during surgical preparation did not significantly improve the fetal acid-base status, but it significantly reduced the use of phenylephrine and ephedrine and reduced the incidence of hypotension; however, these benefits were not observed in the 15° left-tilt group.

Letter commenting on “Ultrasound evaluation of inferior vena cava compression in tilted and supine term parturients”

“…These results are in line with recent findings from randomized controlled trials investigating the lack of efficacy of the 15° left lateral tilt at reducing maternal hypotension or affecting fetal acid base status, 2 further supporting the paradigm shift to finally abandon the practice of lateral tilt in obstetric anesthesia. Nevertheless, the authors’ conclusion of recommending inferior vena cava (IVC) examinations as a potentially useful tool in detecting patients more sensitive to position is debatable.…”

Effect of Different Positions During Surgical Preparation With Combined Spinal-Epidural Anesthesia for Elective Cesarean Delivery: A Randomized Controlled Trial

“…These authors have shown a lack of effect of a lateral tilt of 15 degrees when compared with a supine position in elective cesarean section with crystalloid coloading and phenylephrine infusion 4. Improvements of hemodynamic stability with a 30 degrees lateral tilt—as reported by Liu et al2 is in line with a recent magnetic resonance imaging study in unanesthetised volunteers, where 30 degrees left lateral tilt was most effective in reducing caval compression 5…”

“…Left lateral tilt—an almost perpetual topic in obstetric anesthesia 1. The study by Liu et al2 had to be started twice, the initial plan was to maintain the assigned position (supine, 15 tilt, 30 degrees lateral tilt) during surgery. This was unacceptable for the obstetricians performing the surgery and the study was restarted with a modified protocol, where the allocated position was maintained until surgical preparation and changed to supine afterwards.…”

“…Another variable of interest is the position of the patient when performing neuraxial anesthesia, as well as dosage of intrathecal medication. Both groups, Lee et al2 and Liu et al4 used relatively large doses of intrathecal hyperbaric bupivacaine, 12 and 12.5 mg, respectively. Initiation of spinal anesthesia lateral position leads to a more rapid onset of block by up to 3 minutes, when compared with the sitting position 6.…”

Supine hypotensive syndrome of pregnancy

“…However, the tilt angle did not influence umbilical artery pH between the three groups, indicating that tilt angle may provide no benefit or harm to the fetus. 59 We underestimate the angle Measuring the actual table inclination, established by 16 different anaesthetists for caesarean section, demonstrated that all of them underestimated the angle. 60 Accordingly, a comparable analysis of 100 caesarean sections reported too slight a tilt by visual judgement in 75 patients 61 (Fig.…”