Effect of Trendelenburg head position during cardiac deairing on cerebral microemboli in children: A randomized controlled trial

Objectives: We prospectively evaluated the effects of head position during cardiac deairing on the Doppler ultrasonography-detected cerebral microembo li in children and the association between the embolic counts and the clini cal assessment of deairing. Methods: Children requiring exposure of the systemic ventricle under cardio pulmonary bypass were randomized to Trendelenburg (-15 degrees) and horizon tal (0 degrees) head positions during and after standard surgical deairing. Complexity of repair was categorized as follows: group I consisted of sing le simple lesions, and group II consisted of multiple complex lesions. Tran scranial Doppler ultrasonography identified high-intensity transient signal s in the right middle cerebral artery within the first 5 minutes after aort ic declamping (release) and from this ending period until cardiopulmonary b ypass termination (residual). Electrocardiographic alterations after deairi ng 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 pat ients (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). Dur ing 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 inciden ce 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 deairin g in children does not decrease the cerebral microembolic load compared wit h the horizontal head position. The cerebral microembolic count and the occ urrence of electrocardiographic alterations usually increases when the surg eon is less confident in the efficacy of deairing.