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Bilateral Transranial Doppler Monitoring
During Breath-Holding in Young Amateur Athletes
Jongyeol Kim, Charles H. Tegeler, Greg Collins, ATC, Don Steelman, Patrick Reynolds, David Martin, Winston-Salem, NC; Kevin Westwood, Lewisville, NC
BACKGROUND: Various stimuli such as breath-holding (BH) are used to study cerebral vasomotor reactivity (CVR) during transcranial Doppler monitoring (TCD). BH has advantages of easy use, safety, and noninvasiveness. As a part of an on-going research project on sports related concussions, we studied BH during TCD in young amateur athletes to assess baseline CVR and patterns of response to BH.
METHODS: Seventy-eight football players at Wake Forest University were prospectively enrolled. After routine TCD exam, subjects were asked to hold their breath for 30 seconds after normal inspiration. Mean flow velocities (FV) of the middle cerebral artery (MCA) were continuously recorded bi-laterally, before (30 seconds) during (30 seconds) and after the BH (30-60 seconds). FV changes were expressed as the percentage change in FV format after BH. FV were analyzed at the end of BH (30 seconds) and at the highest FV observed thereafter. Five athletes (All African American) had no acoustic windows.
RESULTS: Seventy-three athletes had TCD during BH (66 bi-laterally, 5 right only, 2 left only). All had increased FV with BH (20.53% at 30 seconds, 41.06% at the highest FV change). There were no significant differences between the right and left MCAs for the percent changes or time to the highest FV. The highest FV changes occurred 10.49 seconds (mean) after the end of BH.
CONCLUSION: This study of a large group of healthy young athletes shows that BH with TCD is an easy-to-use, clinically practical physiological stimulus to assess the CVR. Measuring the peak value of FV after the end of BH provides a higher diagnostic yield. These study data can be used as a baseline to evaluate CVR changes after sports-related concussion and other pathologic conditions.
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