Detected cerebral oxygen desaturations in patients undergoing thoracic surgery

CAS Medical Systems (CASMED) has published two scientific studies demonstrating the use of the Fore-Sight Absolute Cerebral Oximeter in various applications.

The first study, entitled “Reduced cerebral oxygen saturation measured by absolute cerebral oximetry during thoracic surgery correlates with postoperative complications”, was conducted at the Department of Anaesthesiology, Montreal General Hospital, McGill University by Roy Kazan, David Bracco and Thomas Hemmerling.

These researchers concluded that, in 50 patients undergoing thoracic surgery with greater than 45 minutes of single-lung ventilation, a decrease in cerebral tissue oxygenation was seen, and this correlated with post-operative cognitive dysfunction.

Professor Hemmerling, director of Intelligent Technologies in Anesthesia Group, stated: “Using absolute cerebral oximetry, we had recently detected very significant cerebral oxygen desaturations in patients undergoing thoracic surgery with single-lung ventilation to an extent previously only known from cardiac surgery.

“In this study, we found a two-three fold increase in the risk of developing postoperative complications in patients with absolute SctO2 values of 55% or less during single-lung ventilation. While the pathophysiology behind these desaturations necessitates further studies, at present we suggest to monitor cerebral oxygen saturations during single-lung ventilation and to avoid SctO2 values of 55% or below.”

A second study, entitled “Mathematical model for describing cerebral oxygen desaturation in patients undergoing deep hypothermic circulatory arrest”, was conducted by Dr. Gregory Fischer and colleagues at the Department of Anesthesiology and Cardiothoracic Surgery of Mount Sinai Medical Center in New York City.

The study on 36 patients demonstrated that a mathematical model could be created that accurately described the rate of cerebral desaturation during circulatory arrest. These researchers concluded that the proposed model can aid the clinician in determining the length of DHCA (deep hypothermic circulatory arrest) that can be undertaken safely and can be utilized to define the safest time point to commence DHCA.

Dr. Fischer, director of Adult Cardiothoracic Anesthesia, stated: “Currently, there is much heterogeneity among institutions regarding both timing and duration of circulatory arrest. Contemporary protocols are variable and are based on anecdotal or animal-model experiences.

“While our model must still be considered a work in progress, we hope our efforts will make the technique of circulatory arrest more scientific and enable intraoperative management that is tailored to the physiological requirements of the individual patient, which in turn will hopefully result in better outcomes.”