Cerebrovascular carbon dioxide reactivity with propofol anesthesia in patients with previous stroke

Abstract

Study objective To examine whether patients with previous stroke have impaired cerebrovascular carbon dioxide (CO 2) reactivity when receiving propofol anesthesia. Design Prospective, controlled study. Setting University hospital. Patients 34 consecutive patients, 17 of whom had previous stroke and were scheduled for elective cardiac surgery, and 17 control age-matched patients without previous stroke who were also scheduled for cardiac surgery. Interventions Anesthesia was induced and a 2.5-MHz pulsed transcranial Doppler probe was attached to the patient's head at the right temporal window. Mean blood flow velocity of the middle cerebral artery (Vmca) was measured continuously. Measurements After establishing baseline Vmca, arterial blood gases and cardiovascular hemodynamic values, partial pressure of end-tidal CO 2 (PETCO 2) was increased by changing the ventilatory frequency by 2 to 5 breaths/min. The measurements were repeated when PETCO 2 increased and remained stable for 5 to 10 minutes. Main results Values for absolute CO 2 reactivity in the control patients and in those with previous stroke were 2.6 ± 0.5 and 2.9 ± 0.7 cm/sec/mmHg, respectively, a nonsignificant difference in these values. Values for relative CO 2 reactivity in control patients and in patients with previous stroke were 6.4 ± 1.4 and 6.1 ± 1.4%/mmHg, respectively, with no significant difference noted. Conclusions Cerebrovascular CO 2 reactivity in patients with previous stroke is normal during propofol anesthesia.