Changing systems for measuring activated clotting times: impact on the clinical practice of heparin anticoagulation during cardiac surgery.

BACKGROUND: The activated clotting time (ACT) is a standard monitor for heparin anticoagulation during cardiopulmonary bypass (CPB). This study determines the effect of upgrading our ACT system on our clinical practice with regards to the conduct and safety of heparin anticoagulation during cardiopulmonary bypass. METHODS: We compared the intraoperative heparin doses required for all adult cardiac surgery patients (n=1240) and postoperative bleeding for a subset of primary aortocoronary bypass (CABG) surgery procedures (n=285) from cohorts before and after the change in ACT systems. RESULTS: The heparin dose needed to exceed our target ACT of 480 sec for the duration of CPB was higher (45000 vs. 40000 units; p<0.0001), and the mean ACT during CPB was lower (557 vs. 618 sec; p<0.05) using the new ACT system. Furthermore, this coincided with decreased postoperative bleeding in the CABG subset (median value of 417 vs. 575 ml over 12 h; p<0.0005). CONCLUSIONS: We demonstrated that the introduction of the Actalyke ACT system significantly altered our clinical practice by increasing the heparin dose required to exceed our target ACT during CPB. Prospective study to determine the effect of Actalyke ACT system monitoring on hemostasis after cardiac surgery is merited.

Predictive indices of morbidity and mortality after liver resection.

OBJECTIVE: To determine if use of Model for End-Stage Liver Disease (MELD) scores to elective resections accurately predicts short-term morbidity or mortality. SUMMARY BACKGROUND DATA: MELD scores have been validated in the setting of end-stage liver disease for patients awaiting transplantation or undergoing transvenous intrahepatic portosystemic shunt procedures. Its use in predicting outcomes after elective hepatic resection has not been evaluated. METHODS: Records of 587 patients who underwent elective hepatic resection and were included in the National Surgical Quality Improvement Program Database were reviewed. MELD score, CTP score, Charlson Index of Comorbidity, American Society of Anesthesiology classification, and age were evaluated for their ability to predict short-term morbidity and mortality. Morbidity was defined as the development of one or more of the following complications: pulmonary edema or embolism, myocardial infarction, stroke, renal failure or insufficiency, pneumonia, deep venous thrombosis, bleeding, deep wound infection, reoperation, or hyperbilirubinemia. The analysis was repeated with patients divided according to their procedure and their primary diagnosis. Parametric or nonparametric analyses were performed as appropriate. Also, a new index was developed by dividing the patients into a development and a validation cohort, to predict morbidity and mortality in patients undergoing elective hepatic resection. ROC curves were also constructed for each of the primary indices. RESULTS: CTP and ASA scores were superior in predicting outcome. Also, patients undergoing resection of primary malignancies had a higher rate of mortality but no difference in morbidity. CONCLUSION: MELD scores should not be used to predict outcomes in the setting of elective hepatic resection.