[Transcranial Doppler sonography with evaluation of CO2 reactivity in craniocerebral trauma]

17 patients with severe head injury were examined by transcranial Doppler sonography. Resting values and CO2 reactivity were determined. The resting measurements had no prognostic value. There was no significant side difference in patients with unilateral intracranial lesions. CO2 reactivity was 2.8 +/- 2.3%/mmHg pCO2 in patients with good outcome, whereas in patients with bad outcome CO2 reactivity was 0.6 +/- 5.1%/mmHg pCO2. However, in the acute situation after the trauma there was no difference between the two. In patients with a unilateral lesion we found a significantly lower CO2 reactivity on the side of the lesion of 1.8 +/- 0.4%/mmHg pCO2, on the non-affected side CO2 reactivity was 4.5 +/- 2.1%/mmHg pCO2. The conclusion is that the CO2 reactivity yields information on the actual haemodynamic situation in brain-injured patients. Repeated measurements are necessary to improve the prognostic value of CO2 reactivity, because this parameter may improve during treatment.