OBJECTIVES: To study the effect of two protamine-dosing strategies on activated clotting time (ACT) and thromboelastography (TEG). BACKGROUND: Protamine dosage based on neutralizing heparin present in the combined estimated blood volumes (EBVs) of the patient and cardiopulmonary bypass (CPB) pump may result in excess protamine and contributes toward a coagulopathy that can be detected by ACT and TEG in pediatric patients. METHODS: A total of 100 pediatric patients 1 month to ≤5 years of age undergoing CPB were included in this retrospective before/after design study. Combined-EBV group consisted of 50 consecutive patients whose protamine dose was calculated to neutralize heparin in the combined EBVs of the patient and the pump. Pt-EBV group consisted of the next 50 consecutive patients whose protamine dose was calculated to neutralize heparin in the patient's EBV. RESULTS: Baseline and postprotamine ACTs were similar between groups. Postprotamine heparin assay (Hepcon) showed the absence of residual heparin in both groups. Postprotamine kaolin-heparinase TEG showed that R was prolonged by 7.5 min in the Combined-EBV group compared with the Pt-EBV group (mean R of 20.17 vs 12.4 min, respectively, P < 0.001). Increasing doses of protamine were associated with a corresponding, but nonlinear increase in R. There was no significant difference in the changes for K, alpha, and MA between the groups. CONCLUSION: Automated protamine titration with a protamine dosage based on Pt-EBV can adequately neutralize heparin as assessed by ACT while minimizing prolonging clot initiation time as measured by TEG.
[Show abstract][Hide abstract] ABSTRACT: A method for the detection of polyions using fully reversible polyion selective polymeric membrane type pulstrodes as detectors in a flow-injection analysis (FIA) system is examined. The detection electrode consists of a plasticized polymeric membrane doped with 10-wt% of tridodecylmethylammonium-dinonylnaphthalene sulfonate (TDMA-DNNS) ion-exchanger salt. The pulse sequence used involves a short (1 s) galvanostatic pulse, an open-circuit pulse (0.5 s) during which the EMF of the cell is measured, and a longer (15 s) potentiostatic pulse to return the membrane to its original chemical composition. It is shown that total pulse sequence times can be optimized to yield reproducible real-time detection of injected samples of protamine and heparin at up to 20 samples/h. Further, it is shown that the same membrane detector can be employed for FIA detection of both polycations at levels ≥10 µg/mL and polyanions at levels of ≥40 µg/mL by changing the direction of the galvanostatic pulse. The methodology described may also be applicable in the detection of polyionic species at low levels in other flowing configurations, such as in liquid chromatography and capillary electrophoresis.
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