Abstract
A new portable apparatus was developed for non-invasive monitoring of the oxygenation state in human brain. Oxy Hb, deoxy Hb and total Hb content in the brain was measured by near infrared spectrophotometry. Brain oxygenation and blood volume change were continuously monitored in cardiopulmonary bypass (CPB) patients in reflectance mode. During CPB, the brain oxygenation level was maintained roughly constant at mean perfusion pressure over 60mmHg, whereas below 50mmHg the apparent decrease in oxy Hb content was observed. In conclusion, non-invasive monitoring of cerebral oxygenation using NIR light can provide valuable data at bed side about tissue metabolism and allow for the proper management of critical surgical patients.
