Fig. 1.

Study protocol. At different time points, several variables were collected and transcranial color-coded duplex sonography (TCCD) measurements were performed. A = Baseline. B = Increasing minute ventilation. C = Begin moderate hyperventilation with target PaCO₂ 4–4.7 kPa. D = After moderate hyperventilation for 50 min. E = Return to baseline. Glucose, lactate, and pyruvate concentrations in the extracellular fluid were sampled by microdialysis 1 h before A (A − 1 h) and 1 h (D + 1 h) and 2 h after D (D + 2). etCO₂ End-tidal CO₂ (kPa), MV Minute ventilation (L/min), HR Heart rate (beats/min), MAP Mean arterial pressure (mmHg), ICP Intracranial pressure (mmHg), CPP Cerebral perfusion pressure (mmHg), PbrO₂ Brain tissue oxygen tension (mmHg), ABGA Arterial blood gas analysis