Validation of bioimpedance estimates of cardiac output in preeclampsia

Am J Obstet Gynecol. 2000 Oct;183(4):911-3. doi: 10.1067/mob.2000.108892.


Objective: We sought to evaluate the capacity of a new thoracic electric bioimpedance system to estimate cardiac output in patients with preeclampsia.

Study design: We performed a prospective comparison of thoracic electric bioimpedance and echocardiographic M-mode volumetric estimates of cardiac output (in liters per minute) in preeclampsia. Subjects with preeclampsia who were chosen by means of strict criteria (either a systolic blood pressure >/=140 mm Hg or a diastolic blood pressure 90 mm Hg, or both, and proteinuria >/=300 mg in 24 hours or >/=+1 on repeat dipstick measurement 6 hours apart) were asked to participate in an institutional review board-approved study. Thoracic electric bioimpedance and echocardiography were performed with the patients in the left lateral recumbent position. Thoracic electric bioimpedance estimates were recorded at bedside; investigators were blinded to 3 simultaneously obtained echocardiographic M-mode estimates of cardiac output. Means were entered as the estimate for each patient. To satisfy the assumption of independent samples, only 1 estimate from each technique was used for each patient. Data were analyzed by Bland-Altman comparison. Hemodynamic and demographic variables are presented as mean +/- SD.

Results: Fifteen patients were enrolled. Mean maternal age was 25.9 +/- 4.8 years, and mean gestational age was 34.0 +/- 3.5 weeks. Mean arterial pressure was 112 +/- 14 mm Hg. There was good agreement of thoracic electric bioimpedance-derived and M-mode-derived cardiac output estimates.

Conclusions: In patients with preeclampsia, thoracic electric bioimpedance estimates of cardiac output compare well with echocardiographic M-mode estimates.

Publication types

  • Comparative Study
  • Validation Study

MeSH terms

  • Adult
  • Cardiac Output*
  • Echocardiography
  • Electric Impedance
  • Female
  • Humans
  • Pre-Eclampsia / physiopathology*
  • Pregnancy
  • Prospective Studies
  • Single-Blind Method
  • Thorax / physiopathology