[Monitoring cardiac output: esophageal doppler vs thermodilution]

Abstract

Objective: Evaluation of continuous cardiac output monitoring based on the esophageal Doppler in the critically ill.

Design: Prospective clinical investigation.

Setting: An intensive care unit of an University hospital.

Patients: Ten critically ill patients who needed pulmonary artery catheterization.

Measurements: Cardiac output was monitored continuously by a transesophageal Doppler device, consisting of an esophageal probe and a bedside microprocessor that calculated cardiac output using a new algorithm. Standard bolus thermodilution technique (10 ml of saline solution) was used to compare the continuous Doppler cardiac output measurement with the intermittent bolus measurement.

Main results: A total of 50 pairs of intermittent (bolus) cardiac output and continuous (Doppler) cardiac output measurements were obtained from the 10 patients. The mean value of CO measured with TD was 5.81 +/- 0.83, while using esophageal Doppler was 5.84 +/- 0.81. The correlation coefficient of the two methods was r = 0.93. The Bland and Altman showed 95% of agreement limits as +0.52 and -0.64 L/min.

Conclusions: Continuous monitoring of cardiac output using esophageal Doppler has proven to be safe, accurate, and precise when compared with the standard intermittent bolus thermodilution technique. The continuous monitoring technique improves our armamentarium for more intensive monitoring of the critically ill patients.