Successful Use of Intravenous Methylnaltrexone for Opioid-Induced Constipation in Critically Ill Pediatric Patients.

Objectives Methylnaltrexone is U.S. Food and Drug Administration (FDA) approved as a subcutaneous injection for adults with opioid-induced constipation (OIC). Case series have described the use of methylnaltrexone for OIC in the pediatric oncology population. There are limited data describing its intravenous use in critically ill pediatric patients. Methods We conducted a retrospective observational study at St. Louis Children's Hospital. Patients less than 18 years old who received at least one dose of intravenous methylnaltrexone while admitted to an intensive care unit between January 2016 and August 2019 were included. The primary outcome was documented laxation within 24 hours of methylnaltrexone administration. Results Sixteen patients received a total of 34 doses of intravenous methylnaltrexone. Patients received a median of 1.69 (interquartile range [IQR], 0.9-4.86) morphine milligram equivalents per kilogram per 24 hours, over a median of 14 days (IQR, 11-30), before methylnaltrexone administration. The median dose of methylnaltrexone was 0.15 mg/kg (IQR, 0.15-0.16). Ten patients (63%) responded to the first dose of methylnaltrexone, and 14 patients (88%) responded to at least one dose. Overall, 26 doses (76%) led to patient response. Four patients (25%) experienced adverse events (emesis, abdominal pain) after methylnaltrexone administration. No signs or symptoms of opioid withdrawal were documented. Conclusions Intravenous methylnaltrexone appears to be safe and effective in treating OIC in critically ill pediatric patients. No serious adverse events or signs of opioid withdrawal were observed after single and repeat dosing. Patients responded to methylnaltrexone with varying opioid dosing and durations prior to administration.

Impact of Continuous Renal Replacement Therapy on Bivalirudin Dosing in Pediatric Extracorporeal Membrane Oxygenation.

There is an increasing interest in the use of bivalirudin for pediatric extracorporeal membrane oxygenation (ECMO) anticoagulation. However, dosing is not well described in those requiring continuous renal replacement therapy (CRRT). We aimed to determine whether CRRT affects bivalirudin dosing in pediatric ECMO patients. Children ≤18 years of age placed on ECMO and anticoagulated with bivalirudin for ≥24 hours from January 2019 to May 2020 were included. Bivalirudin doses were collected for 144 hours from initiation of bivalirudin or CRRT. Analysis was performed to determine whether CRRT, age, or weight affected bivalirudin dosing. Thirty-one children were included, and 11 (35%) required concomitant CRRT. There was no difference in age (median 9.1 versus 3.2 months, p = 0.15) or days on ECMO (median 11 versus 9, p = 0.7) between those who did or did not receive CRRT. The mean bivalirudin dosing was similar in patients who did or did not require CRRT (median and IQR: 0.13 mg/kg/hour [0.08-0.26] versus 0.15 mg/kg/hour [0.11-0.22], respectively, p = 0.13). Younger age ( p < 0.001) and lower weight ( p < 0.001) were associated with higher bivalirudin dosing. In our study, bivalirudin dosing did not differ if the patient required CRRT while on ECMO.

Antithrombin Dose Optimization in Extracorporeal Membrane Oxygenation in Infants.

Anticoagulation in extracorporeal membrane oxygenation (ECMO) is challenging, with significant morbidity and mortality associated with thrombotic complications. Unfractionated heparin (UFH) is commonly used, which depends on native antithrombin (AT) function to exert anticoagulant effects. Antithrombin deficiency is common in infants on ECMO and replacement with AT concentrate may be warranted. However, dosing recommendations in this population are limited. We conducted a retrospective review of patients <1 year of age who received recombinant AT (ATryn) while on UFH and ECMO between January 1, 2010 and December 31, 2017. Commonly used dosing equations were assessed to determine their ability to predict postdose AT levels. Patient AT levels were compared with equation-predicted postdose AT levels to determine a correlation. A total of 102 doses in 41 patients were used for analysis. Baseline mean AT level was 43% (±13%) and mean AT doses were 134 units (±58.1 units) or 40.5 units/kg (±18.7 units/kg). Median increase in the AT level was 8% (interquartile range 2-17%) with a mean postdose level of 52.6% (±14.2%). Weight-based dosing poorly correlated with postdose AT levels (r2 = 0.082). Postdose levels were best predicted when using an equation that included desired change in the AT level from baseline, the patient's weight, and added weight from the volume of the ECMO circuit (r2 = 0.427). Prospective studies are needed to evaluate optimal dosing strategies, safety, and efficacy of AT in this population.

Is anticoagulation with bivalirudin comparable to heparin for pediatric extracorporeal life support? Results from a high-volume center.

There is a paucity of data regarding the use of direct thrombin inhibitors such as bivalirudin for children on extracorporeal life support (ECLS). We sought to compare the outcomes of children on ECLS anticoagulated with bivalirudin versus heparin. Patients transitioned from heparin to bivalirudin were treated as a separate group. A single-institution, retrospective review of all consecutive children (neonate to 18 years) placed on ECLS in the cardiac or pediatric intensive care units was performed (June 2018-December 2019). Data collected included demographics, anticoagulation strategy, number of circuit interventions, blood product use on ECLS, survival to decannulation, and survival to discharge. Fifty-four children were placed on ECLS for a total of 56 runs. Demographics and venovenous versus venoarterial ECLS were similar. The bivalirudin group had longer median duration of support compared to the heparin group--11.0 days [IQR 6.2, 23.1] versus 3.3 days [2.1, 6.2], P < .001. Patients switched from heparin to bivalirudin had a similar duration of support (10.3 days [8.3, 18.3]) as those on bilvalirudin alone. However, there was no difference in red blood cell, fresh frozen plasma, or platelet transfusions. There was no difference in the number of circuit interventions, survival to decannulation or discharge. The freedom to first circuit intervention was longer with bivalirudin compared to heparin. Our data suggest that even with longer pediatric ECLS runs on bivalirudin, there were no differences in the outcomes between the heparin and bivalirudin groups, with longer freedom from first circuit intervention with bivalirudin. While this is the largest reported series comparing children on ECLS anticoagulated with heparin versus bivalirudin, larger studies are needed to determine the optimal anticoagulation strategy for this diverse and complicated group of children.

Early Post-traumatic Seizure Occurrence in Pediatric Patients Receiving Levetiracetam Prophylaxis With Severe Traumatic Brain Injury.

OBJECTIVE: Although levetiracetam is used for the prevention of early Post-traumatic seizures (EPTS) after traumatic brain injury (TBI), limited data exist describing the incidence of seizures in pediatric patients receiving levetiracetam prophylaxis. The objective of this research is to evaluate the prevalence of EPTS in children given prophylactic levetiracetam after severe TBI. METHODS: This study was conducted at a Level 1 pediatric trauma center and included pediatric patients with severe TBI who received levetiracetam for EPTS prophylaxis. Demographics and clinical information were retrospectively collected and evaluated. The primary outcome was prevalence of clinical or electrographic seizures within 7 days of initial injury as noted in the EMR. RESULTS: In 4 of 44 patients (9%), seizures developed despite levetiracetam prophylaxis. Concurrent use of other medications with antiepileptic properties was common (91%). There were no differences in demographic or baseline clinical characteristics between the group of patients experiencing seizures and those who did not. However, craniotomy was significantly more common in the seizure group (75% vs. 18%, p = 0.03). CONCLUSIONS: Children receiving prophylaxis with levetiracetam after severe TBI had a lower incidence of seizures (9%) than had previously been reported in the literature (18%). Given the limited literature available supporting the use of levetiracetam for the prevention of EPTS in children experiencing severe TBI, further study is needed to support routine use.