S189 INTRODUCTION: Frequent measurements of blood gases and electrolytes may be required to assess critically ill patients in the operating room and in the surgical intensive care unit. An automated on-line blood gas and electrolyte analyzer can expedite the diagnosis and treatment of the conditions of these patients. Also, cost savings of these tests may be achieved by the reduced human resources. The purpose of this study is to validate a newly available VIA blood gas and chemistry monitor with the standard laboratory analyzer in critically ill surgical patients. METHODS: After obtaining IRB approval, eight patients were studied including two patients undergoing liver transplantation, three undergoing cardiac surgery, one with morbid obesity undergoing gastric bypass, and two with multiorgan failure in the SICU. Each patient initially had a radical arterial line inserted. The VIA device (VIA Medical Corp., San Diego, Calif.) was connected to this radical arterial line with a special adapter after two point calibration. Blood samples were drawn by this VIA devise automatically at preset intervals or on demand with simultaneous manual blood sampling. These manually obtained blood samples were analyzed immediately with the standard laboratory analyzer. The results of blood gas, Na, K, and Hgb by the VIA device were compared with the results obtained by the standard laboratory analyzer. In total, 87 paired samples for pH, PCO2, and PO2 and 78 samples for Na, K, and Hgb were obtained. Bias and precision of the device were assessed by employing the Bland & Altman method. Performance bias was evaluated as the mean difference between the paired blood samples and performance precision was evaluated as the standard deviation of the mean difference between the paired samples. RESULTS: The VIA results of 8 critically ill surgical patients providing 87 and 78 paired samples are shown in Table 1. Our results demonstrate that this monitor correlates well with the results of the standard analyzer in the measurement of pH, Na, K, and Hgb. There was a small bias and acceptable precision with PCO2. A weaker correlation was seen in PO2. When PO2 < 100 mmHg, accuracy seemed better.Table 1DISCUSSION: The values of pH, Na, K, and Hgb estimated by this VIA monitor seem to be quite accurate since the paired samples of these correlate closely. The VIA device can be quite a useful tool to guide care of our critically ill patients by providing on-line, automated information of blood gas and chemistry. We believe that this VIA monitor is especially helpful to manage patients undergoing liver transplantation and patients with multiorgan failure.