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

The changes of cerebral blood oxyhemoglobin (HbO2), deoxyhemoglobin (HbR), and total hemoglobin (tHb) induced by acetazolamide and CO2 loading on near-infrared spectroscopy (NIRS) were recorded. In anesthetized 2-week-old rabbits, acetazolamide (10 mg/kg i.v.) increased HbO2 and tHb, concomitant with an increase in tissue PCO2, and decreased HbR only at 5 and 10 min. CO2 loading significantly increased HbR and decreased HbO2, and after the termination of CO2 loading, tHb and HbO2 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 CO2 loading.