The relation between the platelet-activated clotting test (HemoSTATUS) and blood loss after cardiopulmonary bypass.

BACKGROUND: Platelet dysfunction is one of several major causes of bleeding after cardiopulmonary bypass. A timely, simple, point-of-care determinant of platelet function recently became available for clinical use. Adding platelet-activating factor to conventional activated clotting time methods (platelet-activated clotting test [PACT]) produces rapid results (<15 min) and may yield a measure of platelet responsiveness and whole-blood procoagulant activity. METHODS: Blood samples were drawn from 100 patients after cardiac surgery on their arrival in the intensive care unit for PACT, platelet count, prothrombin time (PT), and activated partial thromboplastin time (aPTT). Cumulative blood loss at 4, 8, and 12 h after arrival in the intensive care unit and perioperative transfusion requirements were quantitated. Coagulation tests and mediastinal blood loss were compared using the Spearman rank test and Pearson correlation. The sensitivity and specificity of the laboratory tests for predicting blood loss were analyzed using the receiver operating characteristic method. RESULTS: The PT was the only test that correlated with blood loss at 4, 8, and 12 h. The PACT did not correlate with blood loss at 4, 8, or 12 h, nor did the PACT correlate with the PT or the aPTT. The sensitivity and specificity of the PACT were less than those of the PT in predicting blood loss. Only the PT correlated with platelet and fresh frozen plasma transfusion. CONCLUSIONS: The PT correlated with blood loss and transfusion requirements and was superior to PACT, aPTT, and platelet count for predicting excessive blood loss after cardiopulmonary bypass.

Does the platelet-activated clotting test (HemoSTATUS) predict blood loss and platelet dysfunction associated with cardiopulmonary bypass?

Platelet dysfunction is a major cause of bleeding after cardiopulmonary bypass (CPB). No timely, simple, point-of-care determinant of platelet function is available for clinical use. Adding platelet-activating factor to conventional activated clotting time methods (platelet-activated clotting test [PACT]) (HemoSTATUS; Medtronic, Inc., Parker, CO) produces rapid results (<3 min) and may yield a measure of platelet responsiveness and whole blood procoagulant activity. Blood samples were drawn for PACT, platelet count, prothrombin time, activated partial thromboplastin time, and thromboelastogram (TEG) from 200 patients undergoing cardiac surgery. The PACT significantly decreased from the baseline to postprotamine time interval (P < 0.001). The PACT correlated with 4-h mediastinal blood loss (r = -0.30, P = 0.014). The TEG maximum amplitude also correlated with 4-h mediastinal blood loss (r = -0.32, P = 0.003). The PACT had a sensitivity and specificity comparable to routine laboratory coagulation tests in predicting blood loss. The TEG maximum amplitude, however, was more predictive than both the PACT and routine coagulation tests in this respect. The PACT may be a useful indicator of platelet responsiveness or whole blood procoagulant activity, but we did not find it superior to other tests of coagulation function for predicting excessive blood loss after CPB.

Prophylactic intravenous administration of caffeine and recovery after ambulatory surgical procedures.

OBJECTIVE: To determine whether prophylactic intravenous administration of caffeine, to daily caffeine users, decreases the frequency of postoperative headache and shortens recovery time. DESIGN: The study was a prospective, randomized, double-blind investigation with predetermined sample size and statistical power. MATERIAL AND METHODS: After Mayo Institutional Review Board approval and informed consent were obtained, 300 adult ambulatory surgical patients were enrolled in this study, which included randomization to receive either placebo or caffeine (200 mg intravenously) in the postanesthesia care unit. While recuperating, patients were allowed their choice of postoperative beverages. Before dismissal, patients completed a questionnaire providing details about intake of caffeine and tobacco, history of headache, and demographic data. Patients were considered "at risk" for symptoms of caffeine withdrawal if they did not drink a caffeinated beverage after the surgical procedure. RESULTS: Completed questionnaires were obtained from 234 patients. Patients at risk for symptoms of caffeine withdrawal were less likely to have a postoperative headache if they received caffeine intravenously rather than placebo-10% versus 23% (P < 0.05). Time until recovery was not significantly different between caffeine and placebo study groups. CONCLUSION: We conclude that prophylactic intravenous administration of caffeine was beneficial for those patients at risk for symptoms of caffeine withdrawal. For patients who consume caffeinated beverages on a daily basis, we recommend prophylactic administration of caffeine on the day of an ambulatory surgical procedure and anesthesia.