Neonatal Acid-Base Status After C Section With Maternal Tilt vs. Supine

Aortocaval Compression Clinical Trial

Official title:

Neonatal Acid-base Status After Elective Cesarean Delivery Under Spinal Anesthesia - a Comparison of Maternal Supine Horizontal Position Versus Left Lateral Table Tilt

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT02243423
• Other study ID #: AAAO1851
• Status: Completed
• Phase: N/A
• First received: September 6, 2014
• Last updated: January 22, 2016
• Start date: October 2014
• Est. completion date: January 2016

Study information

• Verified date: January 2016
• Source: Columbia University
• Contact: n/a
• Is FDA regulated: No
• Health authority: United States: Institutional Review Board
• Study type: Interventional

Clinical Trial Summary

This study aims to compare the neonatal acid-base status of women who remain supine horizontal, with women who are tilted to the left side by 15° during elective cesarean delivery at term under spinal anesthesia, with systolic BP maintained at baseline with a phenylephrine (PE) infusion. The null hypothesis is that the position of the patient (supine horizontal or tilted) during cesarean section will make no difference to neonatal wellbeing. The primary outcome will be the neonatal umbilical arterial base deficit (BD) at birth. The investigators will also examine the effects of maternal position during cesarean section under spinal anesthesia on maternal cardiac output (CO) and whether these changes have a correlation with the neonatal umbilical cord blood acid-base status. The secondary outcome will be the total phenylephrine dose requirement at 15 minutes after spinal injection.

Description:

Methods: This will be a randomized trial structured as an equivalence trial. Subjects will be American Society of Anesthesiologists (ASA) I and II women aged ≥18 years, non-laboring, at term (>37 weeks gestation) with singleton pregnancies in cephalic presentation, scheduled for elective cesarean delivery under spinal anesthesia. Patients will receive spinal anesthesia for cesarean section in the sitting position, after which they will lay either supine horizontal or the surgical table will be tilted to the left by 15°, depending on the group to which they were randomized (SUPINE or TILT). An IV phenylephrine infusion will be administered to maintain systolic BP at baseline until delivery. A noninvasive hemodynamic monitoring system (NICOM, Cheetah Medical Inc., Vancouver, WA, USA) will continuously monitor CO and stroke volume. Neonatal umbilical vein and arterial blood gas results will be recorded.The null hypothesis is that the position of the patient (supine horizontal or tilted) during cesarean section will make no difference to neonatal wellbeing.

Statistical Design: The estimated sample size is the minimum number of study subjects required for rejecting the alternative hypothesis (i.e., accepting the null hypothesis). A significant difference between groups in the primary outcome, umbilical artery BD (which is a measure of fetal well being at the time of delivery and an indirect indicator of the adequacy of uteroplacental perfusion) would be of the order of magnitude of 2 mmol/L. Standard deviation of BD tends to be of this magnitude also. It would therefore require 22 subjects per group for 90% power to detect this magnitude of difference with alpha 0.05. Because BD is often not normally distributed, it is appropriate to increase sample size by 10-20%, and because the investigators have important secondary outcomes (PE usage, UA and UV pH, UV BD) the investigators intend to recruit 50 subjects per group to allow sufficient power for analysis of these secondary outcomes with appropriate correction for multiple comparisons, and allowing for 10% dropout. PE usage in the investigators previous study tends to have a standard deviation of about 30% of the mean, also roughly the magnitude of a clinically significant difference.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 100
• Est. completion date: January 2016
• Est. primary completion date: January 2016
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Female
• Age group: 18 Years to 50 Years

Eligibility

Inclusion Criteria:

• ASA I and II women aged =18 years

• Non-laboring

• At term (>37 weeks gestation) with singleton pregnancies in cephalic presentation

• Scheduled for elective cesarean delivery under spinal anesthesia.

• Maternal height will be between 150 - 180 cm and the body mass index (BMI)= 40 kg/m2.

Exclusion Criteria:

• Ruptured membranes

• Severe polyhydramnios or oligohydramnios

• Nonreassuring fetal heart rate

• Intrauterine growth restriction

• Abnormal lie - e.g. breech, transverse lie

• Multiple gestation

• Maternal comorbidities: hypertension, preeclampsia, other cardiovascular disease, renal failure, diabetes mellitus> 10 years, severe scoliosis or kyphosis, uterine abnormalities (e.g. large fibroids, bicornuate uterus)

• Medications - anti-hypertensive agents

• Current smoking or illicit drug use

• Failed spinal (sensory level < T6 after 15 minutes), need to convert to general anesthesia before delivery (exclusion from data analysis

Study Design

Allocation: Randomized, Endpoint Classification: Safety Study, Intervention Model: Factorial Assignment, Masking: Open Label, Primary Purpose: Treatment

Related Conditions & MeSH terms

• Aortocaval Compression
• Fetal Acidosis

Intervention

Procedure:
• SUPINE
Patients in the SUPINE group will receive spinal anesthesia for cesarean section in the sitting position, after which they will lay supine horizontal on the surgical table. A phenylephrine intravenous infusion will be titrated according to a set protocol, to maintain the systolic blood pressure at baseline.
• TILT
Patients will receive spinal anesthesia for cesarean section in the sitting position, after which they will lay on the surgical table, which will be tilted to the left by 15°. A phenylephrine intravenous infusion will be titrated according to a set protocol to maintain the systolic blood pressure at baseline.

Locations

Country	Name	City	State
United States	New York Presbyterian, Allen Hospital	New York	New York

Sponsors (1)

Lead Sponsor	Collaborator
Columbia University

Country where clinical trial is conducted

United States, 

References & Publications (3)

Cluver C, Novikova N, Hofmeyr GJ, Hall DR. Maternal position during caesarean section for preventing maternal and neonatal complications. Cochrane Database Syst Rev. 2013 Mar 28;3:CD007623. doi: 10.1002/14651858.CD007623.pub3. Review. — View Citation

Crawford JS, Burton M, Davies P. Time and lateral tilt at Caesarean section. Br J Anaesth. 1972 May;44(5):477-84. — View Citation

Lee SW, Khaw KS, Ngan Kee WD, Leung TY, Critchley LA. Haemodynamic effects from aortocaval compression at different angles of lateral tilt in non-labouring term pregnant women. Br J Anaesth. 2012 Dec;109(6):950-6. doi: 10.1093/bja/aes349. Epub 2012 Oct 11. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Base deficit (umbilical artery) (mEq/L)	The primary outcome will be the neonatal umbilical arterial base deficit at birth.Neonatal umbilical vein and arterial blood gas results (these are routinely sent by the obstetric service at Columbia University Medical Center for all deliveries)	Within 2 hours of birth	No
Secondary	Total phenylephrine dose (mg)	The secondary outcome will be the total phenylephrine dose requirement at 15 minutes after spinal injection. The phenylephrine (PE) infusion will be titrated to maintain the systolic arterial pressure (SBP) at baseline. If the SBP is at or above baseline, no PE will be administered. If SBP is 90-99% of baseline, PE infusion will be at 50 µg/min. If the SBP is 80-89% of baseline, PE will be 100 µg/min. If SBP is less than 80% of baseline, the infusion will be doubled to 200 µg/min. When SBP returns to more than 90% of baseline, the infusion will be returned to 50 µg/min. If the SBP remains < 80% of baseline after 1 minute at 200 µg/min, additional boluses of IV phenylephrine 80 µg may be given. If this regimen is unsuccessful at restoring SBP to >90% of baseline within 3 minutes, any other indicated maneuver may be used.	15 minutes after spinal injection	No