title: Accuracy and limitations of continuous oesophageal aortic blood flow measurement during general anaesthesia for children: comparison with transcutaneous echography-Doppler.
abstract: BACKGROUND
  Because it is noninvasive and easy to use, oesophageal Doppler ultrasonography appears to be a worthwhile alternative for continuous assessment of cardiac output measurement during anaesthesia. A new oesophageal Doppler-echography device (Dynemo 3000, Sometec, Paris, France) can simultaneously determine aortic diameter and aortic blood flow at the same anatomical level (DEeso). The purpose of this study was to assess the accuracy and the potential limitations of this device during general anaesthesia among 20 children, using transcutaneous Doppler-echocardiography for comparison (DEtra).
  
  
  METHODS
  The reproducibility of paired measurements of mean aortic blood flow velocity (MAFV), aortic diameter (ØAo) and aortic blood flow (ABF) was analysed with both methods. Second, haemodynamic values were measured simultaneously in a blinded manner by both methods before and after surgery.
  
  
  RESULTS
  The percent change (%Delta) in MAFV and ABF was calculated with both methods for each child. The age and weight of children included in this study was 8.3 +/- 2.5 years and 27 +/- 8 kg, respectively. Intraoperator reproducibility of MAFVtra, ABFtra, MAFVeso and ABFeso, was 5.0 +/- 4.1%, 7.0 +/- 5.6%, 20.1 +/- 17.5% and 22.0 +/- 16.6%, respectively. ABFtra was significantly linked to ABFeso (R=0.55, P < 0.01). Bias +/- SD of ABF measurements between both methods was 2.2 +/- 1.1 l. min-1. %DeltaABFtra was significantly linked to %DeltaABFeso (R=0.62, P < 0.01). The bias +/- SD inherent to %DeltaABF measurements with both methods was -0.02 +/- 18%.
  
  
  CONCLUSIONS
  These results suggest that this new oesophageal Doppler method is unsuitable to measure accurately absolute CO values and relative CO changes in children during anaesthesia.
authors.affiliation: Department of Anesthesiology and Surgical Intensive Care, Centre Hospitalier Regional et Universitaire, 2 rue Henri le Guilloux, 35033 Rennes Cedex 9, France.
authors.forename: E
authors.initials: E
authors.lastname: Wodey
authors.forename: V
authors.initials: V
authors.lastname: Gai
authors.forename: F
authors.initials: F
authors.lastname: Carre
authors.forename: C
authors.initials: C
authors.lastname: Ecoffey
mesh_terms: D000768:Anesthesia, General; D001011:Aorta / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology*; D002648:Child; D015150:Echocardiography, Doppler; D017548:Echocardiography, Transesophageal; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D016343:Monitoring, Intraoperative; D012039:Regional Blood Flow / Q000502:physiology; D015203:Reproducibility of Results