title: A validation study of electrical cardiometry in pregnant patients using transthoracic echocardiography as the reference standard.
abstract: To validate electrical cardiometry (EC) in pregnant patients using transthoracic echocardiography (TTE) as the reference standard. To improve EC accuracy via a one-time, measurement of left ventricular outflow tract (LVOT) diameter. 44 non-laboring, resting women with singleton, viable pregnancies underwent simultaneous EC and TTE measurements. Data were analyzed using Bland-Altman analysis. Entry multiple regression with stepwise elimination was used to develop a model for improved prediction of stroke volume by TTE (SVTTE) using EC. Bootstrapping and an 11-fold cross validation were used to test the model. Heart rate by TTE and EC had a mean bias of 3.3 beats/min and mean percentage error of 10.7 %. Envelope time and left ventricular ejection time had a mean bias of -4.9 ms and mean percentage error 12.7 %. Stroke volumes by the two techniques had a mean bias of 15.6 mL and mean percentage error of 43.7 %. A model, SVEC_Modified, predicting SVTTE was developed using LVOT area, stroke volume by electrical cardiometry and weight. SVTTE and SVEC_Modified had a mean bias of -0.83 mL and mean percentage error of 22 %. EC accurately measures heart rate and duration of systole when compared with TTE. Stroke volume measurements correlate but have a high bias and percentage error. Knowledge of LVOT area, by a one-time, measurement with TTE, could improve prediction of stroke volume by EC.
authors.affiliation: Department of Anesthesiology, University of California, San Diego, 200 W. Arbor Drive, San Diego, CA, 92103, USA. emart005@gmail.com.
authors.forename: Erin
authors.initials: E
authors.lastname: Martin
authors.affiliation: Department of Anesthesiology, University of California, San Diego, 200 W. Arbor Drive, San Diego, CA, 92103, USA.
authors.forename: Adanna
authors.initials: A
authors.lastname: Anyikam
authors.affiliation: Department of Anesthesiology, University of California, San Diego, 200 W. Arbor Drive, San Diego, CA, 92103, USA.|Obstetrics and Gynecology, Baylor College of Medicine, One Baylor Plaza, BCM 610, Houston, TX, 77030, USA.
authors.forename: Jerasimos
authors.initials: J
authors.lastname: Ballas
authors.affiliation: Department of Anesthesiology, University of California, San Diego, 200 W. Arbor Drive, San Diego, CA, 92103, USA.|Women's Clinic, 710 Lawrence Expressway, Santa Clara, CA, 95051, USA.
authors.forename: Kristen
authors.initials: K
authors.lastname: Buono
authors.affiliation: Department of Anesthesiology, University of California, San Diego, 200 W. Arbor Drive, San Diego, CA, 92103, USA.
authors.forename: Kristin
authors.initials: K
authors.lastname: Mantell
authors.affiliation: Department of Anesthesiology, University of California, San Diego, 200 W. Arbor Drive, San Diego, CA, 92103, USA.
authors.forename: Thao
authors.initials: T
authors.lastname: Huynh-Covey
authors.affiliation: Department of Anesthesiology, University of California, San Diego, 200 W. Arbor Drive, San Diego, CA, 92103, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Archer
mesh_terms: D000328:Adult; D001024:Aortic Valve Stenosis / Q000503:physiopathology*; D002302:Cardiac Output; D003430:Cross-Sectional Studies; D004452:Echocardiography / Q000379:methods*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006352:Heart Ventricles / Q000503:physiopathology*; D006439:Hemodynamics; D006801:Humans; D015233:Models, Statistical; D008991:Monitoring, Physiologic / Q000379:methods; D011247:Pregnancy; D011446:Prospective Studies; D012015:Reference Standards; D012044:Regression Analysis; D015203:Reproducibility of Results; D013318:Stroke Volume / Q000502:physiology*; D013599:Systole / Q000502:physiology; D055815:Young Adult
keywords: Cardiac output; Electrical cardiometry; Impedance cardiography