Evaluation of Bivalirudin During Adult Extracorporeal Membrane Oxygenation: A Retrospective Characterization of Dosing, Efficacy and Bleeding.

Objective: Although heparin is the current standard anticoagulant during venoarterial (VA) and venovenous (VV) extracorporeal membrane oxygenation (ECMO), factors including heparin-induced thrombocytopenia, heparin resistance and drug shortages necessitate alternative anticoagulants such as direct thrombin inhibitors. The aim was to characterize dosing, safety, and efficacy of bivalirudin during ECMO support. Methods: This retrospective single-center study included 24 adults on ECMO support who received ≥6 hours of bivalirudin. The primary endpoint was dose to first therapeutic activated partial thromboplastin time (aPTT). Secondary endpoints included evaluating dosing between ECMO modes, incidence of bleeding and thrombotic events, and time in therapeutic range (TTR). Results: The dose at time of first therapeutic aPTT was bivalirudin 0.05 [0.05-0.1] mg/kg/hour. Bivalirudin dosing requirements were lower in VAECMO compared to VV-ECMO patients and were not impacted by continuous venovenous hemofiltration. Time to therapeutic aPTT was 5.5 [2-13] hours for VA-ECMO and 4.5 [2-8.6] hours for VV-ECMO patients. During any mode of ECMO TTR was 58.3% [39.6-73.1]. Thrombotic events occurred in 3 (13%) patients and major bleeding occurred in 12 (50%) patients. Conclusions: Our findings demonstrated variable bivalirudin dosing requirements based on mode of ECMO and dosing modifications may not be required during CVVH. Factors including mode of ECMO, indication for bivalirudin and concomitant antiplatelet therapy may impact hematologic events. Application of this data can assist with developing a bivalirudin ECMO protocol which provides less variability in initial dosing and TTR.

Filter clotting with continuous renal replacement therapy in COVID-19.

Coronavirus disease 2019 (COVID-19) appears to be associated with increased arterial and venous thromboembolic disease. These presumed abnormalities in hemostasis have been associated with filter clotting during continuous renal replacement therapy (CRRT). We aimed to characterize the burden of CRRT filter clotting in COVID-19 infection and to describe a CRRT anticoagulation protocol that used anti-factor Xa levels for systemic heparin dosing. Multi-center study of consecutive patients with COVID-19 receiving CRRT. Primary outcome was CRRT filter loss. Sixty-five patients were analyzed, including 17 using an anti-factor Xa protocol to guide systemic heparin dosing. Fifty-four out of 65 patients (83%) lost at least one filter. Median first filter survival time was 6.5 [2.5, 33.5] h. There was no difference in first or second filter loss between the anti-Xa protocol and standard of care anticoagulation groups, however fewer patients lost their third filter in the protocolized group (55% vs. 93%) resulting in a longer median third filter survival time (24 [15.1, 54.2] vs. 17.3 [9.5, 35.1] h, p = 0.04). The rate of CRRT filter loss is high in COVID-19 infection. An anticoagulation protocol using systemic unfractionated heparin, dosed by anti-factor Xa levels is reasonable approach to anticoagulation in this population.

Evaluation of Vasopressor Exposure and Mortality in Patients With Septic Shock.

OBJECTIVES: The objectives of this study were to: 1) determine the association between vasopressor dosing intensity during the first 6 hours and first 24 hours after the onset of septic shock and 30-day in-hospital mortality; 2) determine whether the effect of vasopressor dosing intensity varies by fluid resuscitation volume; and 3) determine whether the effect of vasopressor dosing intensity varies by dosing titration pattern. DESIGN: Multicenter prospective cohort study between September 2017 and February 2018. Vasopressor dosing intensity was defined as the total vasopressor dose infused across all vasopressors in norepinephrine equivalents. SETTING: Thirty-three hospital sites in the United States (n = 32) and Jordan (n = 1). PATIENTS: Consecutive adults requiring admission to the ICU with septic shock treated with greater than or equal to 1 vasopressor within 24 hours of shock onset. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Out of 1,639 patients screened, 616 were included. Norepinephrine (93%) was the most common vasopressor. Patients received a median of 3,400 mL (interquartile range, 1,851-5,338 mL) during the 24 hours after shock diagnosis. The median vasopressor dosing intensity during the first 24 hours of shock onset was 8.5 µg/min norepinephrine equivalents (3.4-18.1 µg/min norepinephrine equivalents). In the first 6 hours, increasing vasopressor dosing intensity was associated with increased odds ratio of 30-day in-hospital mortality, with the strength of association dependent on concomitant fluid administration. Over the entire 24 hour period, every 10 µg/min increase in vasopressor dosing intensity was associated with an increased risk of 30-day mortality (adjusted odds ratio, 1.33; 95% CI, 1.16-1.53), and this association did not vary with the amount of fluid administration. Compared to an early high/late low vasopressor dosing strategy, an early low/late high or sustained high vasopressor dosing strategy was associated with higher mortality. CONCLUSIONS: Increasing vasopressor dosing intensity during the first 24 hours after septic shock was associated with increased mortality. This association varied with the amount of early fluid administration and the timing of vasopressor titration.

Accelerated Venovenous Hemofiltration as a Transitional Renal Replacement Therapy in the Intensive Care Unit.

BACKGROUND: Continuous renal replacement therapy (CRRT) is commonly employed in the intensive care unit (ICU), though there are no guidelines around the transition between CRRT and intermittent hemodialysis (iHD). Accelerated venovenous hemofiltration (AVVH) is a modality utilizing higher hemofiltration rates (4-5 L/h) with shorter session durations (8-10 h) to "accelerate" the clearance and volume removal that normally is spread out over a 24-h period in CRRT. We examined AVVH as a transition therapy between CRRT and iHD, with the aim of decreasing time on CRRT and providing a more graduated transition for hemodynamically unstable patients requiring RRT. METHODS: Retrospective cohort study describing the clinical outcomes and quality initiative experience of the integration of AVVH into the CRRT program at an academic tertiary care center. Outcomes of interest included mortality, ICU length of stay and readmission rates, and technical characteristics of treatments. RESULTS: In total, 97 patients received a total of 298 AVVH treatments (3.1 ± 3.3 treatments per patient). Totally, 271/298 (91%) treatments were completed successfully. During an average treatment time of 9.5 ± 1.6 h with 4.2 ± 0.5 L/h -replacement fluid rate, urea reduction ratio was 23 ± 26% per 10-h treatment, and net ultrafiltration volume was 2.4 ± 1.3 L/treatment. Inpatient mortality was 32%, mean total hospital length of stay was 54 ± 47 days. Sixty-four out of 97 (66%) patients recovered renal function by discharge. Among those who transferred out of the ICU, 7/62 (11%) patients required readmission to the ICU after developing hypotension on iHD. CONCLUSION: AVVH can serve as a transition therapy between CRRT and iHD in the ICU and has the potential to decrease total time on CRRT, improve patient mobility, and sustain low ICU readmission rates. Future study is needed to analyze the implications on resource use and cost of this modality.

Argatroban for Heparin-Induced Thrombocytopenia during Venovenous Extracorporeal Membrane Oxygenation with Continuous Venovenous Hemofiltration.

Patients receiving extracorporeal membrane oxygenation (ECMO) are at risk of circuit thrombosis due to constant contact between blood and the extracorporeal components. Unfractionated heparin has traditionally been used in this setting as a systemic form of anticoagulation to prevent thrombosis of the circuit. However, if a patient develops heparin-induced thrombocytopenia (HIT), an alternative anticoagulant would be required while the patient is maintained on ECMO. Unfortunately, the pharmacokinetic changes induced by ECMO and critical illness may potentially affect optimal drug dosing. In addition, other modalities, such as continuous renal replacement therapy, may further complicate dosing strategies. We report the case of a 27-year-old man with severe acute respiratory distress syndrome who developed HIT while on venovenous ECMO with continuous venovenous hemofiltration. We describe the successful use of an argatroban infusion in this setting at much higher doses than what has previously been reported in the adult literature.

Vancomycin removal and pharmacokinetics during accelerated venovenous hemofiltration.

INTRODUCTION: Vancomycin pharmacokinetics are affected by renal replacement therapy and physiologic changes in critically ill patients. Literature regarding vancomycin removal and pharmacokinetics during accelerated venovenous hemofiltration (AVVH), a form of prolonged intermittent renal replacement therapy, is limited. OBJECTIVE: To describe the removal and pharmacokinetics of vancomycin during AVVH. METHODS: Eighteen critically ill adults receiving vancomycin and AVVH were included. Vancomycin serum concentrations were obtained within 4 h before and 2-6 h after the AVVH session. Patients' serum concentrations were plotted against time, and individual pharmacokinetic parameters were determined by a one-compartmental analysis. Continuous data are reported as a median (interquartile range [IQR]) and categorical data as a percentage. RESULTS: The median AVVH effluent rate was 39.3 mL/kg/h (IQR 35.5-48 mL/kg/h) for a duration of 9 h (IQR 8-9.75 h). AVVH decreased vancomycin concentrations by 29.8% (IQR 24.9%-35.9%), at a rate of 3.4% per hour (IQR 3.1%-4.3% per hour) of AVVH. The vancomycin elimination rate constant and half-life were 0.039 h-1 (IQR 0.036-0.053 h-1 ) and 17.6 h (IQR 13.1-18.8 h), respectively. The area under the curve during AVVH was 171.7 mg*h/L (IQR 149.1-190 mg*h/L). The volume of distribution in 10 patients was 1 L/kg (IQR 0.73-1.1 L/kg). After AVVH, vancomycin 1000 mg (IQR 750-1000 mg) was needed to maintain a serum trough concentration ≥15 mg/L. CONCLUSION: Vancomycin is significantly removed by AVVH, which requires supplemental dosing after completion of the AVVH session to maintain desired serum concentrations. Therapeutic drug monitoring of vancomycin serum concentrations is recommended for patients undergoing AVVH.

Epoprostenol Exposure During Pregnancy.

Institutional policies restricting pregnant providers from caring for patients receiving inhaled epoprostenol exist across the nation based on little to no data to substantiate this practice. Over the last 2 decades, the use of inhaled pulmonary vasodilators has expanded in patients with cardiac and respiratory disease providing more evidence for the safety of these medications in obstetrical patients. We propose a thoughtful consideration and review of the literature to remove this restriction to reduce the need to reveal early pregnancy status to employers, to alleviate undue stress for pregnant caregivers who are exposed to patients receiving epoprostenol, and to ensure safe, equal employment, and learning opportunities for pregnant providers.

Differences in midterm outcomes in infants with hypoplastic left heart syndrome diagnosed with necrotizing enterocolitis: NPCQIC database analysis.

INTRODUCTION: Neonates with hypoplastic left heart syndrome (HLHS) are at increased risk for necrotizing enterocolitis (NEC). Initial hospital outcomes are well described, but minimal midterm data exist. Goal of this study was to compare outcomes of HLHS infants with NEC (HLHS-NEC) to HLHS without NEC (HLHS-nNEC) during the interstage period. METHODS: Data were reviewed from 55 centers using the NPC-QIC database. Case-control study with one HLHS-NEC matched to HLHS-nNEC neonates in a 1:3 ratio based on institutional site, type of surgical repair, and gestational age ±1 week was performed. Baseline demographics as well as outcome data were recorded. The t tests or chi-square tests were performed as appropriate. RESULTS: There were 57 neonates in the HLHS-NEC (14 Norwood-BT, 37 Norwood-RVPA, and 6 hybrid) and 171 neonates in the HLHS-nNEC group. There were significant differences between the HLHS-NEC versus HLHS-nNEC for presence of atrioventricular valve regurgitation (7% vs 2%), use of extracorporeal membrane oxygenation (11% vs 2%), hospital stay (60.4 ± 30.0 vs 36.3 ± 33.6 days), Z-score weight at discharge (-2.1 vs -1.6), incidence of no oral intake (33% vs 14%), and use of formula only nutrition at discharge (61% vs 29%), respectively. There were no significant differences between groups in readmission rates due to adverse gastrointestinal events, use of gastrointestinal medications, interstage deaths, or Z-score weight at time of second surgery. HLHS-NEC continued to be more likely to be entirely tube dependent for enteral intake at time prior to the second procedure (39% vs 15%). CONCLUSIONS: Despite similar baseline characteristics, HLHS-NEC infants had significant differences in hospital course compared with HLHS-nNEC neonates. In addition, HLHS-NEC infants were less likely to be fed orally during the entire interstage period. Future studies are needed minimize NEC in this high risk population to possibly improve oral feeds.

Fluconazole pharmacokinetics in a morbidly obese, critically ill patient receiving continuous venovenous hemofiltration.

Current fluconazole dosing strategies can be described using either standardized doses (800 or 400 mg) or as weight-based dosing recommendations (12 mg/kg loading dose followed by 6 mg/kg maintenance dose). The ideal method of fluconazole dosing is still unclear for certain patient populations, such as those receiving renal replacement therapy or the morbidly obese. We describe a 48-year-old man with a body mass index of 84 kg/m(2) who was receiving continuous venovenous hemofiltration (CVVH) and was treated with fluconazole by using a weight-based dose determined by lean body weight, infused at a rate of 200 mg/hour. Blood samples were collected at hour 0 (i.e., ~24 hrs after the loading dose was administered) and at 3.5, 6.8, and 11.3 hours after the start of the 600-mg maintenance dose, infused over 3 hours. Pharmacokinetic parameters calculated were maximum serum concentration 9.64 mg/L, minimum serum concentration 5.98 mg/L, area under the serum concentration-time curve from 0-24 hours (AUC0-24 ) 184.75 mg/L•hour, elimination rate constant 0.0199 hour(-1) , elimination half-life 34.8 hours, and total body clearance 3.25 L/hour. Our data, when combined with previously published literature, do not support using a linear dose-to-AUC approximation to estimate drug dosing needs in the critically ill patient population receiving CVVH. In addition, our results suggest that morbidly obese patients are able to achieve pharmacodynamic goals defined as an AUC:MIC ratio higher than 25 by using a lean body weight for fluconazole dosing calculations.