Evaluation of a Multimodal Heparin Laboratory Monitoring Protocol in Adult Extracorporeal Membrane Oxygenation Patients.

BACKGROUND: Anticoagulation monitoring practices vary during extracorporeal membrane oxygenation (ECMO). The Extracorporeal Life Support Organization describes that a multimodal approach is needed to overcome assay limitations and minimize complications. OBJECTIVE: Compare activated clotting time (ACT) versus multimodal approach (activated partial thromboplastin time (aPTT)/anti-factor Xa) for unfractionated heparin (UFH) monitoring in adult ECMO patients. METHODS: We conducted a single-center retrospective pre- (ACT) versus post-implementation (multimodal approach) study. The incidence of major bleeding and thrombosis, blood product and antithrombin III (ATIII) administration, and UFH infusion rates were compared. RESULTS: Incidence of major bleeding (69.2% versus 62.2%, p = 0.345) and thrombosis (23% versus 14.9%, p = 0.369) was similar between groups. Median number of ATIII doses was reduced in the multimodal group (1.0 [IQR 0.0-2.0] versus 0.0 [0.0 -1.0], p = 0.007). The median UFH infusion rate was higher in the ACT group, but not significant (16.9 [IQR 9.6-22.4] versus 13 [IQR 9.6-15.4] units/kg/hr, p = 0.063). Fewer UFH infusion rate changes occurred prior to steady state in the multimodal group (0.9 [IQR 0.3 -1.7] versus 0.1 [IQR 0.0-0.2], p < 0.001). CONCLUSION: The incidence of major bleeding and thrombosis was similar between groups. Our multimodal monitoring protocol standardized UFH infusion administration and reduced ATIII administration.

Performance of a dose-defining insulin infusion protocol among trauma service intensive care unit admissions.

BACKGROUND: Among critically ill patients, glycemic control reduces mortality and morbidities, but the use of intravenous insulin infusion is complicated by hypoglycemia. Having a standardized algorithm increases the likelihood of effective and safe utilization of intravenous insulin therapy. A tabular dose-defining protocol for intravenous insulin infusion is described, containing design elements intended to minimize risk for hypoglycemia while seeking control in a narrow target range, and performance is evaluated among critically ill trauma service patients. METHODS: The protocol assigns insulin infusion rate (IR) for ranges of blood glucose (BG). The columns are arranged in order of increasing maintenance rate (MR) for insulin infusion. Patient column assignment is determined according to rate of change of BG. During stable column assignment, the IR is a function of column MR and BG. Within-column, the protocol formula provides that (a) for BG between 70 mg/dL and target BG, the IR increases exponentially to the column MR; and (b) for BG above upper target BG range, the IR increases linearly as an adaptation of the rule of 1800, with slope determined by the column MR. Values for IR calculated by formula are rounded to correspond to BG ranges of the table. Performance was assessed in 27 sequential runs among 24 trauma service patients admitted to a surgical intensive care unit (2004-2005). RESULTS: Using point-of-care measurements, mean preinfusion BG was 230.0 +/- 67.9 mg/dL. BG < 140 mg/dL was reached during all 27 runs (median time 5.0 h), and target BG was < 110 mg/dL during 25 runs (median time 11.0 h). For the group of runs attaining target before interruption of insulin infusion, the average +/- SD of the principal measure of glycemic control, the within-run mean BG, was 113.7 +/- 14.8 mg/dL (coefficient of variation 13%, n = 25 runs). After attaining target, the average within-run SD for BG was 22.9 mg/dL. The within-run frequency of hypoglycemic measurements (BG < 70 mg/dL) as a percentage of BG determinations was 2.4%. In this series, no instance of BG <50 mg/dL was seen. CONCLUSIONS: This report describes a nurse-implemented tabular protocol for intravenous insulin infusion having the advantages of efficacy, safety, and simplicity of use. Wide variability of IR in the neighborhood of BG 110 mg/dL is associated with stable BG response, and protection against hypoglycemia is achieved by rapid decline of IR at BGs in or below the target range.

Optimal dose of enoxaparin in critically ill trauma and surgical patients.

BACKGROUND: Low-molecular-weight heparin is effective for prevention of venous thromboembolism. The efficacy of daily dosing in critically ill patients is unknown. METHODS: Seventeen critically ill patients on 40 mg of enoxaparin subcutaneously daily were studied. Anti-Xa activity was measured 4 hours after the third dose and before the fourth dose. Adverse events were recorded. RESULTS: Mean peak anti-Xa activity was 0.19 +/- 0.09 International Units/mL and mean trough was 0.044 +/- 0.04 International Units/mL. The recommended target range is 0.1 to 0.2 International Units/mL. The trough was below therapeutic levels in all but two patients. One thrombosis occurred in a patient despite a therapeutic trough. CONCLUSION: Daily dosing of enoxaparin is inadequate for critically ill patients and should be abandoned. Further studies using twice daily dosing are needed. Patients with renal insufficiency may require an increased interval of administration (daily dosing). Anti-Xa levels may not correlate with the risk of thromboembolic complications. Patients with renal insufficiency and morbid obesity may require alternative dosing and monitoring of anti-Xa levels.