title: Validation of bioimpedance estimates of cardiac output in preeclampsia.
abstract: OBJECTIVE
  We sought to evaluate the capacity of a new thoracic electric bioimpedance system to estimate cardiac output in patients with preeclampsia.
  
  
  METHODS
  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.
authors.affiliation: Spartanburg Regional Medical Center, Spartanburg, SC, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Scardo
authors.forename: J
authors.initials: J
authors.lastname: Ellings
authors.forename: S T
authors.initials: ST
authors.lastname: Vermillion
authors.forename: S P
authors.initials: SP
authors.lastname: Chauhan
mesh_terms: D000328:Adult; D002302:Cardiac Output; D004452:Echocardiography; D017097:Electric Impedance; D005260:Female; D006801:Humans; D011225:Pre-Eclampsia / Q000503:physiopathology*; D011247:Pregnancy; D011446:Prospective Studies; D016037:Single-Blind Method; D013909:Thorax / Q000503:physiopathology