title: Effect of Trendelenburg head position during cardiac deairing on cerebral microemboli in children: a randomized controlled trial.
abstract: OBJECTIVE
  We prospectively evaluated the effects of head position during cardiac deairing on the Doppler ultrasonography-detected cerebral microemboli in children and the association between the embolic counts and the clinical assessment of deairing.
  
  
  METHODS
  Children requiring exposure of the systemic ventricle under cardiopulmonary bypass were randomized to Trendelenburg (-15 degrees ) and horizontal (0 degrees ) head positions during and after standard surgical deairing. Complexity of repair was categorized as follows: group I consisted of single simple lesions, and group II consisted of multiple complex lesions. Transcranial Doppler ultrasonography identified high-intensity transient signals in the right middle cerebral artery within the first 5 minutes after aortic declamping (release) and from this ending period until cardiopulmonary bypass termination (residual). Electrocardiographic alterations after deairing were documented. A predefined 5-point scale was used by the surgeon for blinded assessment of deairing.
  
  
  RESULTS
  High-intensity transient signals were identified in 97% of 128 patients (aged 5 days to 17 years). The median total high-intensity transient signal count was 60 (25th-75th quartiles, 14-189). Head position or surgeon did not affect the rate of high-intensity transient signals (P >.20). During the residual interval, occurrence of HITS in group I was less than that in group II (P <.05), but there was no difference at release. The incidence of high-intensity transient signals and electrocardiographic alterations correlated with the clinical assessment of deairing (P <.01).
  
  
  CONCLUSIONS
  Trendelenburg head position as a complement of cardiac deairing in children does not decrease the cerebral microembolic load compared with the horizontal head position. The cerebral microembolic count and the occurrence of electrocardiographic alterations usually increases when the surgeon is less confident in the efficacy of deairing.
authors.affiliation: Division of Cardiovascular Surgery, the Departments of Surgery, Biostatistics, and Anaesthesia, Children's Hospital of Eastern Ontario, CHEO Research Institute and University of Ottawa, Ottawa, Ontario, Canada. Rodriguez@CHEO.ON.CA
authors.forename: R A
authors.initials: RA
authors.lastname: Rodriguez
authors.forename: G
authors.initials: G
authors.lastname: Cornel
authors.forename: N A
authors.initials: NA
authors.lastname: Weerasena
authors.forename: B
authors.initials: B
authors.lastname: Pham
authors.forename: W M
authors.initials: WM
authors.lastname: Splinter
mesh_terms: D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D002315:Cardiopulmonary Bypass / Q000009:adverse effects; D002675:Child, Preschool; D004618:Embolism, Air / Q000000981:diagnostic imaging* / Q000209:etiology; D018475:Head-Down Tilt; D006330:Heart Defects, Congenital / Q000601:surgery*; D006801:Humans; D007223:Infant; D020766:Intracranial Embolism / Q000000981:diagnostic imaging* / Q000209:etiology; D016343:Monitoring, Intraoperative / Q000379:methods*; D011446:Prospective Studies; D017585:Ultrasonography, Doppler, Transcranial