Transcranial color-coded duplex sonography assessment of cerebrovascular reactivity to carbon dioxide: an interventional study

Background: The investigation of CO2 reactivity (CO2-CVR) is used in the setting of, e.g., traumatic brain injury (TBI). Transcranial color-coded duplex sonography (TCCD) is a promising bedside tool for monitoring cerebral hemodynamics. This study used TCCD to investigate CO2-CVR in volunteers, in sedated and mechanically ventilated patients without TBI and in sedated and mechanically ventilated patients in the acute phase after TBI. Methods: This interventional investigation was performed between March 2013 and February 2016 at the surgical ICU of the University Hospital of Zurich. Ten volunteers (group 1), ten sedated and mechanically ventilated patients (group 2), and ten patients in the acute phase (12-36 h) after severe TBI (group 3) were included. CO2-CVR to moderate hyperventilation (Delta CO2-5.5 mmHg) was assessed by TCCD. Results: CO2-CVR was 2.14 (1.20-2.70) %/mmHg in group 1, 2.03 (0.15-3.98) %/mmHg in group 2, and 3.32 (1.184.48)%/mmHg in group 3, without significant differences among groups. Conclusion: Our data did not yield evidence for altered CO2-CVR in the early phase after TBI examined by TCCD.

Automated summary

This study used TCCD to investigate CO2-CVR in different groups of individuals, with results showing no significant differences in CO2-CVR among volunteers, sedated and mechanically ventilated patients without TBI, and sedated and mechanically ventilated patients in the acute phase after TBI.