title: Validation of esophageal Doppler for noninvasive hemodynamic monitoring under pneumoperitoneum.
abstract: BACKGROUND
  Commonly used perioperative measurements of hemodynamics, such as Swan-Ganz catheter assessment, are invasive and may not be reliable under pneumoperitoneum. The purpose of this study was to validate the use of esophageal Doppler for noninvasive hemodynamic monitoring under pneumoperitoneum in an experimental pig model.
  
  
  METHODS
  Eight female pigs were submitted to two 30-min study periods, one each for the baseline (no interventions) and pneumoperitoneum (12-mmHg carbon dioxide pneumoperitoneum) conditions. One pig was excluded because of tachycardia (>140 at baseline). A Swan-Ganz pulmonary artery catheter was used to measure cardiac output (CO-SG) and pulmonary capillary wedge pressure (PCWP). An esophageal Doppler probe was inserted to record cardiac output (CO-ED) and corrected flow time (FTc), an index of preload. Transthoracic echocardiography was used to measure left ventricular end-diastolic diameter (LVEDD) and cardiac output (CO-TTE). Pearson correlation was used to assess individual associations between the measured hemodynamic parameters.
  
  
  RESULTS
  There was good correlation between CO-ED and CO-SG (r = 0.577; p < 0.001) and excellent correlation between CO-ED and CO-TTE (r = 0.815; p < 0.001). There was no correlation between FTc and LVEDD or PCWP. These relationships were consistent when analyzed separately at baseline and during pneumoperitoneum.
  
  
  CONCLUSIONS
  Esophageal Doppler monitoring is a valid noninvasive method of estimating cardiac output at baseline and during pneumoperitoneum in a porcine model. Corrected flow time did not correlate with other estimates of preload at baseline or during pneumoperitoneum.
authors.affiliation: Steinberg-Bernstein Centre for Minimally Invasive Surgery, McGill University, 1650 Cedex Avenue, Montreal, QC, H3G 1A4, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Okrainec
authors.forename: S
authors.initials: S
authors.lastname: Bergman
authors.forename: S
authors.initials: S
authors.lastname: Demyttenaere
authors.forename: L S
authors.initials: LS
authors.lastname: Feldman
authors.forename: A
authors.initials: A
authors.lastname: Nutting
authors.forename: F
authors.initials: F
authors.lastname: Carli
authors.forename: G M
authors.initials: GM
authors.lastname: Fried
mesh_terms: D000818:Animals; D001011:Aorta; D001783:Blood Flow Velocity; D002302:Cardiac Output; D002320:Cardiovascular Physiological Phenomena; D002407:Catheterization, Swan-Ganz; D004452:Echocardiography; D017548:Echocardiography, Transesophageal; D005260:Female; D008991:Monitoring, Physiologic; D011028:Pneumoperitoneum, Artificial; D011669:Pulmonary Wedge Pressure; D034421:Sus scrofa; D016277:Ventricular Function, Left