Utility of esophageal Doppler as a minimally invasive hemodynamic monitor: a review.

PURPOSE: The current bedside "gold standard" for cardiac output (CO) monitoring is thermodilution using a pulmonary artery catheter (PAC) but there is a number of risks associated with its use. The primary objective of this review was to evaluate the utility of esophageal Doppler (ED) as a minimally invasive monitor of CO. SOURCE: Medline literature search from 1966 to 2001 with citation review for studies comparing ED to PAC thermodilution for CO in perioperative and critically ill patients. PRINCIPAL
FINDINGS: Twenty-five publications were identified comparing ED and PAC measurement of CO in a broad range of patients. There was a good overall correlation between CO determined by ED and thermodilution (n = 18 studies, median R = 0.89, range 0.52 to 0.98) and minimal bias (n = 13, median -0.01, range 1.38 to 2 L x min(-1)). The precision of ED was only fair overall as assessed by limits of agreement. The ED technique was found to be responsive in detecting changes in thermodilution CO and was reliable demonstrating both low intra- and inter-observer variation. ED was reportedly easy to insert after minimal training and was safe, with no significant complications identified.
CONCLUSION: ED is a practical, reliable, and valid device for measuring CO in perioperative and critically ill patients. Further studies with larger numbers of patients are needed to determine if the limited precision observed is inherent to the technique, the diagnoses of patients studied, or the small sample sizes.