Introduction: Transesophageal Echocardiography (TEE) is frequently used in pediatric cardiac surgery. Although widely accepted to be a safe procedure, compression of vascular structures by the TEE probe may occur. We present a previously undescribed phenomenon wherein insertion of a TEE probe significantly altered cerebral blood flow measured via transcranial doppler over the middle cerebral artery.

Methods: This was a case-control study of nine patients, using each patient’s contralateral middle cerebral artery as the control. Cases were identified intra-operatively, on the basis of a 10% or larger decrease in cerebral blood flow velocity during insertion of the TEE. The contralateral side was employed as a control. Results were analysed using both parametric and non-parametric testing methods.

Results: All events involved the left-sided blood flow; two were associated with significant regional cerebral desaturation. When compared to the right side, the decrease in cerebral blood flow seen with probe insertion was statistically significant (p<0.05). All events resolved with removal of the TEE probe.

Conclusion: This series indicates a need for due diligence. TEE may have deleterious effects on cerebral blood supply, and factors clearly identifying those at risk have yet to be identified. In the event of a significant change seen in cerebral blood flow with TEE insertion, which cannot be resolved by repositioning the head or probe, removal of the probe with subsequent post-operative re-insertion may be indicated. This affects a minority of patients, and seems appropriate to avoid potential hours of compromised cerebral perfusion.