Time in Therapeutic Range for Bivalirudin Among Pediatric Ventricular Assist Device Recipients.

Given the adverse event rates involving bleeding and thrombosis among children on ventricular assist devices (VADs), anticoagulant management has become a focal point for quality improvement and innovation. There may be advantages to using direct thrombin inhibitors, such as bivalirudin, though this has not been fully explored. As the percent time in therapeutic range (%TTR) for anticoagulants is classically associated with improved clinical outcomes, we evaluated the %TTR for bivalirudin among pediatric VAD recipients. Using a modification of the Rosendaal method, %TTR was calculated using activated partial thromboplastin time measurements for 11 VAD recipients in the early postoperative period (postoperative days 0-14) and for the duration of VAD support. In the initial 2 weeks after VAD implant, mean %TTR was 68.7 (±13.0). During the entire support course, the mean %TTR improved to 79.6 (±11.0). There was an era effect with improving %TTR in the latter half of the study period. We report very good %TTR for bivalirudin both in the first 2 weeks post implant and this improved over the duration of support. Because %TTR reflects the degree of safety and efficacy in chronic anticoagulation, this relatively high %TTR among a diverse, often critically ill cohort suggests that bivalirudin may be a promising agent. Although this study was underpowered to comprehensively evaluate adverse events on bivalirudin, this represents an important next step for larger scale study.

Stability of dexmedetomidine 4 µg/mL in polypropylene syringes.

PURPOSE: The results of a study to determine the long-term (up to 14 days) stability of diluted dexmedetomidine kept in polypropylene syringes under typical pharmacy storage conditions are presented. METHODS: Four samples of dexmedetomidine injection diluted to 4 µg/mL in 0.9% sodium chloride were prepared and divided into 25-mL portions for storage in syringes at ambient room temperature (20-25 °C) with light exposure or under refrigeration (5 °C) in darkness. At 24 and 48 hours, the percentage of the initial dexmedetomidine concentration remaining in all samples was assessed via high-performance liquid chromatography with diode-array detection; further stability testing of the refrigerated samples was performed on days 7 and 14. At each time point, the test samples were visually inspected for color, clarity, and signs of formation of particulate matter. RESULTS: As determined by chromatographic analyses, the samples of diluted dexmedetomidine stored in syringes at room temperature exhibited a loss of drug concentration of <10% over 48 hours; the refrigerated samples exhibited a loss of drug concentration of <5% over 14 days. All of the syringe-stored samples remained clear and colorless on visual inspection for the duration of the study. CONCLUSION: Dexmedetomidine diluted to 4 µg/mL in 0.9% sodium chloride injection was stable for at least 48 hours at 20-25 °C and 14 days at 5 °C when stored in polypropylene syringes.