Background and Aim: The clinical applicability of substitution of central venous oxygen saturation for mixed venous oxygen saturations in monitoring global tissue hypoxia is still a matter of controversy. Hence aim of the study is comparison of paired samples of mixed venous and central venous oxygen saturation and comparison in relation to cardiac index in varying hemodynamic conditions. Materials and Methods: Prospective clinical observation: Postoperative cardiac surgical ITU: 60 adult patients, >18 years of age of either sex: A PAC was inserted through ® IJV, triple lumen catheter was inserted through ® IJV. Blood samples were taken from distal tip of PAC and central venous catheters. An arterial blood sample was drawn from either radial or femoral arterial line. Measurements: Continuous cardiac output monitoring. Analysis of blood samples for hemoglobin concentration and oxygen saturation. Mixed venous oxygen saturations and central venous oxygen saturations were compared. The study was carried over a period of 30h in the postoperative period and samples were taken at 6h intervals. Patients were classified into three groups as follows depending on the CI: Low (< 2.5 L/m 2), medium (2.5-4 L/m 2), high (> 4 L/ m 2) and correlated with Svo 2 and Scvo 2. Results: 298 Comparative sets of samples were obtained. Svo consistently lower than Scvo 2 throughout the study period. The difference was statistically significant. By using Bland-Altman plot, the mean difference between Svo 2 and Scvo 2 (Svo 2-Scvo 2) was-2.9% ± 5.14 and confidence limits are + 7.17% and-12.97%. The coefficient r is > 0.7 throughout the study period for all paired samples. The correlation Svo 2 and Scvo 2 with cardiac index in all the three groups were >0.7. Conclusion: Scvo 2 and Svo 2 are closely related and are interchangeable. Even though individual values differ trends in Scvo 2 may be substituted for trend in Svo 2

Transfusion associated graft versus host disease (TA-GVHD) is a rare but commonly fatal complication of transfusion of cellular blood products, which usually occurs in immunosuppressed individuals following transfusion and subsequent engraftment of viable T lymphocytes. Very rarely it may arise in apparently immunocompetent individuals. The clinical syndrome consists of fever, skin rash, diarrhoea, hepatic dysfunction, and bone marrow aplasia. The outcome is nearly always fatal. We present here a case report of fatal TA-GVHD in a “presumed” immunocompetent patient, post coronary artery bypass grafting surgery after transfusion of blood products. The patient died 24 days after transfusion.There is a perceived increased risk of TA-GVHD following bypass grafting and other surgical procedures where cardiopulmonary bypass is required. TA-GVHD is probably underreported and the incidence is felt to be too low to warrant routine irradiation of cellular products for this group of patients. Clinicians, pathologists, and transfusion centers should be aware of this rare but devastating complication of blood transfusion after cardiac surgery.