Amer J Perinatol
DOI: 10.1055/s-0037-1615788
Original Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Stroke Volume Recruitability during the Third Trimester of Pregnancy

Sandra Herrera
Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, The University of Texas Medical Branch at Galveston, Galveston, Texas
,
Maggie J. Kuhlmann-Capek
Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, The University of Texas Medical Branch at Galveston, Galveston, Texas
,
Sarah C. Rogan
Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, The University of Texas Medical Branch at Galveston, Galveston, Texas
,
Antonio F. Saad
Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, The University of Texas Medical Branch at Galveston, Galveston, Texas
,
George R. Saade
Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, The University of Texas Medical Branch at Galveston, Galveston, Texas
,
Gary D. V. Hankins
Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, The University of Texas Medical Branch at Galveston, Galveston, Texas
,
Luis D. Pacheco
Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, The University of Texas Medical Branch at Galveston, Galveston, Texas
Department of Anesthesiology, The University of Texas Medical Branch at Galveston, Galveston, Texas
› Author Affiliations
Further Information

Publication History

23 August 2017

16 November 2017

Publication Date:
26 December 2017 (eFirst)

Abstract

Objective It is unknown whether the heart operates in the ascending or flat portion of the Starling curve during normal pregnancy. Pregnant women do not respond to the passive leg-raising maneuver secondary to mechanical obstruction of the inferior vena cava by the gravid uterus. Our objective was to evaluate if administration of a fluid bolus increases baseline stroke volume (SV) among healthy pregnant patients during the third trimester.

Study Design Healthy pregnant women who underwent elective term cesarean sections were included. A noninvasive cardiac output monitor was used to measure hemodynamic variables at baseline and after administration of a 500-mL crystalloid bolus.

Results Forty-five women were included in the study. Fluid administration was associated with a statistically significant increase in SV from a baseline value of 71 ± 11 to 90 ± 19 mL (95% confidence interval [CI]: 13.67–21.49; p < 0.01) and a significant decrease in maternal heart rate from a baseline of 87 ± 9 beats per minute to 83 ± 8 after the fluid bolus (95% CI: −6.81 to −2.78; p = 0.03). No changes in peripheral vascular resistances or any other measured hemodynamic parameters were noted with volume expansion.

Conclusion In healthy term pregnancy, the heart operates in the ascending portion of the Starling's curve, rendering it fluid responsive.