title: Exploring measurement biases associated with esophageal Doppler monitoring in critically ill patients in intensive care unit.
abstract: BACKGROUND
  Esophageal Doppler monitoring (EDM) is utilized in numerous clinical settings. This study examines the relationship between pulmonary artery catheter (PAC) and EDM-derived hemodynamic parameters, concentrating on gender- and age-related EDM measurement biases.
  
  
  METHODS
  Prospective study of EDM use in ventilated surgical ICU patients. Parameters examined included demographics, diagnosis, resuscitation endpoints, cardiac output (CO) and stroke volume from both devices, number of personnel and time needed to place equipment, time to data acquisition, duration of use, complications of placement.
  
  
  RESULTS
  Fifteen patients (11 men, 4 women, mean age 47 years) were included. Most common diagnoses included trauma (7/15) and sepsis (4/15). Insertion time and time to data acquisition were shorter for EDM than for PAC (P<0.001). The EDM required an average of 1.1 persons to place (2.4 for PAC, P=0.002). Mean EDM utilization time was 12.4 h. There was a fair CO correlation between EDM and PAC (r = 0.647, P<0.001). Overall, the EDM underestimated CO relative to PAC (bias -1.42 +/- 2.08, 95% CI: -5.58-2.74), with more underestimation in women (mean bias difference of -1.16, P<0.001). No significant age-related measurement bias differences between PAC and EDM were noted. Significant reductions in lactate and norepinephrine requirement were noted following EDM monitoring periods.
  
  
  CONCLUSIONS
  This study found that the EDM significantly underestimated cardiac output in women when compared to PAC. Clinicians should be aware of this measurement bias when making therapeutic decision based on EDM data. Significant reductions in lactate and norepinephrine requirement during EDM monitoring periods support the clinical usefulness of EDM technology.
authors.affiliation: Department of Surgery, Division of Traumatology and Surgical Critical Care, University of Pennsylvania School of Medicine, 3440 Market Street, 1 Floor, Philadelphia, PA 19104-3335, USA. waliso@ngha.med.sa
authors.forename: Peter S
authors.initials: PS
authors.lastname: Stawicki
authors.forename: Benjamin
authors.initials: B
authors.lastname: Braslow
authors.forename: Vicente H
authors.initials: VH
authors.lastname: Gracias