The effect of acetazolamide and carbon dioxide on cerebral hemodynamic changes on near-infrared spectroscopy in young rabbits

The changes of cerebral blood oxyhemoglobin (HbO 2), deoxyhemoglobin (HbR), and total hemoglobin (tHb) induced by acetazolamide and CO 2 loading on near-infrared spectroscopy (NIRS) were recorded. In anesthetized 2-week-old rabbits, acetazolamide (10 mg/kg i.v.) increased HbO 2 and tHb, concomitant with an increase in tissue PCO 2, and decreased HbR only at 5 and 10 min. CO 2 loading significantly increased HbR and decreased HbO 2, and after the termination of CO 2 loading, tHb and HbO 2 significantly increased and HbR decreased to nearly the baseline value. Thus, NIRS demonstrated cerebral hemodynamic responses as a function of vasomotor reactivity to acetazolamide as well as CO 2 loading.