The Esophageal Doppler. In: Vincent J, editor. Yearbook of Intensive Care and Emergency Medicine 1999. Berlin: Springer Berlin Heidelberg; 1999. pp. 482-93. [DOI: 10.1007/978-3-662-13453-5_42]

Oesophageal Doppler Ultrasound in the Assessment of Haemodynamic Status of Patients Admitted to the Medical Intensive Care Unit with Septic Shock

Introduction: Haemodynamic monitoring is an essential element in the management of critically ill patients in the intensive care unit (ICU). However, there have been increasing concerns about the clinical utility and safety profile of the invasive pulmonary artery catheter (PAC). Oesophageal Doppler (ED) monitoring has emerged recently as a safer and less invasive tool which can be used by the intensivist to estimate cardiac output in the critically ill patient. Validation studies have thus far only been performed in surgical patients perioperatively and in mixed surgical/medical ICU patients. Currently, minimal data are available in any sizeable Asian population or in patients with severe sepsis. The assumption that these normograms and data hold true for our local medical ICU patients may not be valid due to differences in body habitus. Materials and Methods: Our primary aim is to validate the oesophageal Doppler as a reliable measure of cardiac index, systemic vascular resistance (SVR) and preload in our local Asian population of patients with severe sepsis and septic shock in the medical ICU. This was a prospective pilot study on 12 consecutive mechanically ventilated patients in our medical ICU with the diagnosis of septic shock as defined by SCCM/ESICM/ACCP/ATS/SIS International Sepsis definitions Conference – Critical Care Medicine 2003 and required PAC haemodynamic monitoring as indicated by Medical Intensive Care Unit attending. Results: Ninety-seven paired cardiac output measurements were made. Cardiac output ranged from 2.87 to 11.0 L/ min (calculated cardiac index ranging from 1.73 to 6.36 L/min/m2) when measured using the PAC with thermodilution technique and from 2.0 to 12.1 L/min (calculated cardiac index of 1.2 to 7.2 L/min/m2) using the trans-oesophageal Doppler. There was moderately good correlation between CIpac and CIed (correlation coefficient, r = 0.762 with PCA = 58%). The mean bias was 0.26 L/min/m2 (P <0.07), while the limit of agreement was ± 1.44 L/min/m2. Conclusion: ED has good correlation with PAC in measuring cardiac index in Asians with septic shock but is an unreliable measure of both pre-load and SVR. Key words: Cardiac index, Pulmonary artery cathether, Systemic vascular resistance

The validity of trans-esophageal Doppler ultrasonography as a measure of cardiac output in critically ill adults

OBJECTIVE

To determine the validity of the esophageal Doppler monitor (EDM) and echo-esophageal Doppler (Echo-ED) in measuring cardiac output in the critically ill.

DESIGN

Systematic search of relevant international literature and data synthesis.

SEARCH STRATEGY

Literature search (1989-2003) using Ovid interface to Medline, Embase and Cochrane databases aimed at finding studies comparing EDM or Echo-ED cardiac output with that derived from simultaneous pulmonary artery thermodilution (PAC(TD)) with Bland Altman measures of validity.

PATIENTS

Critically ill adults in operating departments or intensive care units.

DATA SYNTHESIS

Summary validity measures synthesized from Bland Altman analyses included pooled median bias and the median percentage of clinical agreement (PCA) derived from the limits of agreement.

MAIN RESULTS

Eleven validation papers for EDM (21 studies) involving 314 patients and 2,400 paired measurements. The pooled median bias for PAC(TD) versus EDM was 0.19 l/min (range -0.69 to 2.00 l/min) for cardiac output (16 studies), and 0.6% (range 0-2.3%) for changes in cardiac output (5 studies). The pooled median percentage of clinical agreement for PAC(TD) versus EDM was 52% (interquartile range 42-69%) for cardiac output and 86% (interquartile range 55-93%) for changes in cardiac output. These differences in PCA were significant ( p=0.03 Mann-Whitney) for bolus PAC(TD) as the clinical "gold standard". We found an insufficient number of studies (2 papers) to assess the validity of Echo-ED.

CONCLUSIONS

The esophageal Doppler monitor has high validity (no bias and high clinical agreement with pulmonary artery thermodilution) for monitoring changes in cardiac output.