Decreased perioperative cerebral oxygenation values linked to poor outcomes after aortic arch surgery

Jul 15 2010

CAS Medical Systems, Inc. (Nasdaq:CASM) today announced that a new study published in The Journal of Thoracic and Cardiovascular Surgery supports the association between decreased perioperative cerebral oxygenation values and poor outcomes after aortic arch surgery.

The study from researchers in the Departments of Anesthesiology and Cardiothoracic Surgery, at Mount Sinai School of Medicine, Mount Sinai Medical Center, New York, NY used CASMED's FORE-SIGHT^® Absolute Cerebral Oximeter to observe the affects of decreased intraoperative brain oxygen saturation in patients undergoing aortic arch surgery. Additionally, the researchers sought to identify absolute cerebral oxygen saturation threshold values that are predictive of organ dysfunction.

In this prospective study, the researchers found a statistically significant association between the accumulated duration of decreased cerebral tissue oxygen saturation (SctO2) and severe adverse outcomes (SAO), including major complications defined as death, stroke with persistent neurological deficits, new heart problems, respiratory failure, severe infection, delirium, new kidney failure, gastrointestinal complications and severe fluid retention. Using logistical regression, they found that the risk of SAO increased as a function of both accumulated duration of desaturation and decreasing SctO2 threshold value. As such, for every 5% decrease in the absolute SctO2 threshold, the incremental exposure time to achieve a given odds ratio (for SAO) decreased by half for SctO2 thresholds between 55% and 65%.

In addition, researchers also observed an association between lower absolute SctO2 values and prolonged time on mechanical ventilation, prolonged ICU stay and extended hospital length of stay, noting, "Patients who spent more than 30 minutes under the absolute threshold of 60% had an extended hospital stay of 4 days leading to an additional cost of $8,300."

Lead author, Gregory W. Fischer, M.D., Director of Adult Cardiothoracic Anesthesia and Associate Professor Anesthesiology & Cardiothoracic Surgery at Mount Sinai Medical Center, stated, "Surgical aortic arch repair is technically challenging and is associated with considerable morbidity and mortality. A potential advantage of absolute brain tissue oximetry is that threshold values may be more strongly associated with adverse outcomes than trend values. The results from the study lends further evidence to support the association between decreased perioperative cerebral oxygenation values and poor patient outcomes. While further studies will be helpful to show the impact of interventions at these thresholds, these results lend credibility to the emerging hypothesis that SctO2 monitoring may be useful as an indicator of overall organ perfusion and injury, and may lead to decreased hospital costs associated with major cardiac surgery. While it is too early to recommend specific target SctO2 values that should be maintained in different clinical settings. On a very preliminary basis, using the technology in this study in the clinical setting of thoracic aortic surgery, we believe that an SctO2 of 60% to 65% could represent this threshold value."