Changes in cerebrovascular reactivity (CVR) to carbon dioxide (CO2) are reported in many neurological conditions. My aim was to validate a method for computerized prospective targeting of CO2 levels (RespiractTM) as a bedside tool for impaired CVR. I hypothesized that 1) The RespiractTM and TCD method can be used to detect impairment of CVR after SAH and that 2) CVR is impaired in SAH patients. In 18 SAH patients and 26 controls CVR index was calculated dividing the percentage change in middle cerebral artery blood flow velocity (MCAv) by the change in PETCO2. The absolute MCAv values were similar in both groups, but CVR was significantly different (hypercapnia: 0.044 ± 0.076 - controls; 0.014 ± 0.037 - SAH; p=0.0007). I showed that impaired CVR can be detected at the bedside using TCD and CO2 challenge with the RespiractTM, control of CO2 is precise and minimal changes are required.

Changes in cerebrovascular reactivity (CVR) to carbon dioxide (CO2) are reported in many neurological conditions. My aim was to validate a method for computerized prospective targeting of CO2 levels (RespiractTM) as a bedside tool for impaired CVR. I hypothesized that 1) The RespiractTM and TCD method can be used to detect impairment of CVR after SAH and that 2) CVR is impaired in SAH patients. In 18 SAH patients and 26 controls CVR index was calculated dividing the percentage change in middle cerebral artery blood flow velocity (MCAv) by the change in PETCO2. The absolute MCAv values were similar in both groups, but CVR was significantly different (hypercapnia: 0.044 ± 0.076 - controls; 0.014 ± 0.037 - SAH; p=0.0007). I showed that impaired CVR can be detected at the bedside using TCD and CO2 challenge with the RespiractTM, control of CO2 is precise and minimal changes are required.