Meropenem Population Pharmacokinetics and Dosing Regimen Optimization in Critically Ill Children Receiving Continuous Renal Replacement Therapy.

BACKGROUND AND OBJECTIVE: We aimed to develop a meropenem population pharmacokinetic model in critically ill children receiving continuous renal replacement therapy and simulate dosing regimens to optimize patient exposure. METHODS: Meropenem plasma concentration was quantified by high-performance liquid chromatography. Meropenem pharmacokinetics was investigated using a non-linear mixed-effect modeling approach. Monte Carlo simulations were performed to compute the optimal scheme of administration, according to the target of a 100% inter-dose interval time in which concentration is one to four times above the minimum inhibitory concentration (100% fT>1-4×MIC). RESULTS: A total of 27 patients with a median age of 4 [interquartile range 0-11] years, a median body weight of 16 [range 7-35] kg receiving continuous renal replacement therapy were included. Concentration-time courses were best described by a one-compartment model with first-order elimination. Body weight (BW) produced significant effects on volume of distribution (V) and BW and continuous renal replacement therapy effluent flow rate (Qeff) produced significant effects on clearance (CL): [Formula: see text] and [Formula: see text], where Vpop and CLpop estimates were 32.5 L and 5.88 L/h, respectively, normalized to a 70-kg BW and median Qeff at 1200 mL/h. Using this final model and Monte Carlo simulations, for patients with Qeff over 1200 mL/h, meropenem continuous infusion was adequate in most cases to attain 100% fT>1-4xMIC. For bacterial infections with a low minimum inhibitory concentration (≤2 mg/L), meropenem intermitent administration was appropriate for patients weighing more than 20 kg with Qeff <500 mL/h and for patients weighing more than 10 kg with Qeff <100 mL/h. CONCLUSIONS: Meropenem exposure in critically ill children receiving continuous renal replacement therapy needs dosing adjustments to the minimum inhibitory concentration that take into account body weight and the continuous renal replacement therapy effluent flow rate.

Antithrombin supplementation for prevention of vascular thrombosis after pediatric liver transplantation.

AIMS: After liver transplantation (LT), synthesis of coagulation factors by the graft recovers faster for pro thrombotic than anti thrombotic factors, resulting in a potential pro thrombotic imbalance. We studied the thrombotic and hemorrhagic complications in our pediatric LT series, providing supplementation of fresh frozen plasma (FFP) and/or antithrombin (AT) in the prophylactic antithrombotic regimen. METHODS: This was a retrospective observational single center study. All isolated pediatric LTs performed between 1/11/2009 and 31/12/2019 (n = 181) were included. Postoperatively, in addition to low molecular weight heparin, 22 patients (12%) received FFP (10 ml/kg twice daily for 10 days), 27 patients (15%) were given FFP (reduced duration) and AT (50-100 IU/kg/day if AT activity remained <70%), and 132 (73%) received AT only. Complications, outcome, and coagulation profiles in postoperative days 0-10 were analyzed. RESULTS: In all three treatment groups, AT activity normalized by day 4 while prothrombin remained <70% of normal until day 9. Hepatic artery thrombosis (HAT), portal vein thrombosis (PVT), and hemorrhagic complications occurred in 2.8%, 3.3%, and 3.9% of LTs. One- and 5-year patient and graft survival were 88% (±2.4% Standard Error) and 84% (±2.5%), and 86% (±2.6%) and 84% (±2.7%), respectively, without difference between groups. HAT were associated with low AT on days 0 and 1, and PVT with low AT on day 0. CONCLUSIONS: Low antithrombin activity after LT was associated with postoperative thromboses. FFP and/or AT supplementation allowed early normalization of AT activity, while thrombotic or hemorrhagic complications were rare, suggesting efficient and safe management of post-LT coagulopathy.

Therapeutic Drug Monitoring of Antibiotics in Critically Ill Children: An Observational Study in a Pediatric Intensive Care Unit.

BACKGROUND: Septic critically ill children are at a high risk of inadequate antibiotic exposure, requiring them to undergo therapeutic drug monitoring (TDM). The aim of this study was to describe the use of TDM for antibiotics in critically ill children. METHODS: The authors conducted a single-center observational study between June and December 2019, with all children treated with antibiotics in a pediatric intensive care unit located in a French university hospital. Standard clinical and laboratory data were recorded. Blood samples were collected for routine laboratory tests, and plasma antibiotic levels were assayed using validated analytical methods. RESULTS: A total of 209 children received antibiotics. TDM was performed in 58 patients (27.8%) who had a greater mean organ dysfunction (according to the International Pediatric Sepsis Consensus Conference) (3 versus 1 in the non-TDM group; P < 0.05) and were treated with antibiotics for longer. A total of 208 samples were analyzed. The median [interquartile range] assay turnaround time was 3 (1-5) days, and 48 (46.2%) of the 104 initial antibiotic concentration values were below the pharmacokinetic/pharmacodynamic targets. A total of 34 (46%) of the 74 off-target TDM measurements available before the end of the antibiotic treatment prompted dose adjustment. This dose adjustment increased the proportion of on-target TDM measurements (70% versus 20% without adjustment). Subsequent measurements of the minimum inhibitory concentration showed that the use of the European Committee on Antimicrobial Susceptibility Testing's epidemiological cutoff values led to underestimation of pharmacokinetic/pharmacodynamic target attainment in 10 cases (20%). CONCLUSIONS: TDM seems to be an effective means of optimizing antibiotic exposure in critically ill children. This requires timely plasma antibiotic assays and minimum inhibitory concentration measurements. It is important to define which patients should undergo TDM and how this monitoring should be managed.

Methionine supplementation for multi-organ dysfunction in MetRS-related pulmonary alveolar proteinosis.

INTRODUCTION: Pulmonary alveolar proteinosis related to mutations in the methionine tRNA synthetase (MARS1) gene is a severe, early-onset disease that results in death before the age of 2 years in one-third of patients. It is associated with a liver disease, growth failure and systemic inflammation. As methionine supplementation in yeast models restored normal enzymatic activity of the synthetase, we studied the tolerance, safety and efficacy of daily oral methionine supplementation in patients with severe and early disease. METHODS: Four patients received methionine supplementation and were followed for respiratory, hepatic, growth and inflammation-related outcomes. Their course was compared to those of historical controls. Reactive oxygen species production by patient monocytes before and after methionine supplementation was also studied. RESULTS: Methionine supplementation was associated with respiratory improvement, clearance of the extracellular lipoproteinaceous material and discontinuation of whole-lung lavage in all patients. The three patients who required oxygen or noninvasive ventilation could be weaned off within 60 days. In addition, liver dysfunction, inflammation and growth delay improved or resolved. At a cellular level, methionine supplementation normalised the production of reactive oxygen species by peripheral monocytes. CONCLUSION: Methionine supplementation was associated with important improvements in children with pulmonary alveolar proteinosis related to mutations in the MARS1 gene. This study paves the way for similar strategies for other tRNA synthetase deficiencies.

Early Bacterial Infections After Pediatric Liver Transplantation in the Era of Multidrug-resistant Bacteria: Nine-year Single-center Retrospective Experience.

BACKGROUND: Early bacterial infection is a major and severe complication after liver transplantation (LT). The rise of antimicrobial resistance, especially extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE), is a growing concern for these patients. This study aimed to assess the epidemiology of early bacterial infections in a pediatric population, including those caused by multidrug-resistant (MDR) pathogens, and to identify risk factors for infection. METHODS: We conducted a monocentric retrospective study including 142 consecutive LTs performed in 137 children between 2009 and 2017. RESULTS: Ninety-three bacterial infections occurred after 67 (47%) LTs. Among the 82 isolated pathogens, the most common was Klebsiella pneumoniae (n = 19, 23%). Independent risk factors for early bacterial infection were low weight [odds ratio (OR) = 0.96; 95% confidence interval (CI): 0.9-0.99; P = 0.03] and the presence of a prosthetic mesh (OR = 2.4; 95% CI: 1.1-5.4; P = 0.046). Sixty-one children (45%) carried MDR bacteria and 16 infections were caused by MDR pathogens, especially ESBL-producing K. pneumoniae (n = 12). ESBL-PE stool carriage was associated with ESBL-PE infection (OR = 4.5; 95% CI: 1.4-17.4; P = 0.02). Four children died from an infection, three due to ESBL-producing K. pneumoniae. CONCLUSIONS: This study confirmed a shift toward a predominance of Gram-negative early bacterial infections after pediatric LT. The risk factors for infection were low weight and the presence of a prosthetic mesh. ESBL-PE stool carriage was associated with ESBL-PE infection. Adapted antimicrobial prophylaxis and personalized antibiotherapy are mandatory to reduce infection prevalence and mortality.

Parental perceptions of clown care in paediatric intensive care units.

AIM: The objective of this study was to report family satisfaction with regards to the presence of clowns in the paediatric intensive care unit (PICU). METHODS: This is a single-centre survey-based study, conducted over 4 months in a 12-bed third level PICU in a university hospital. All parents present at the bedside of their child during clowning were considered as potential participants. Eligible parents were approached by one of the two intensivists as investigators and asked to complete a survey within the 48 h following the clowns' intervention. RESULTS: Thirty-three parents consented to complete the survey. Median age of children was 14 months (15 days to 16 years) and median Pediatric Logistic Organ Dysfunction (PELOD) score was 1 (0-22). Twenty-four (72.7%) were considered as clinically stable while the clowns intervened. Twenty-eight parents (84.8%) and 27 (81.8%) considered that clowns had a positive effect on themselves and on their child, respectively. Clown care was considered as necessary in 19 cases (57.6%), optional in 13 (39.4%) and unnecessary in 1 (3.0%). The degree of parental satisfaction was not significantly associated with the child's clinical stability. CONCLUSION: We suggested that medical clowning in the PICU is well accepted by parents, regardless of severity of their child's condition. This study supports the adoption of medical clowning in PICUs as a patient- and family-centred care practice.

Astrocyte responses after neonatal ischemia: the yin and the yang.

Neonatal encephalopathy is a major predictor of neurodevelopmental disability in term infants and occurs in 1 to 6 of every 1,000 live term births. Despite improvements in perinatal practice during the past several decades, the incidence of cerebral palsy attributed to neonatal asphyxia remained essentially unchanged, primarily because management strategies were supportive and not targeted toward the processes of ongoing injury. Traditionally, experimental research in vivo focused on neurons, and more recently, oligodendrocytes whereas astrocytes have been more or less neglected. This review aims at dissecting possible protective as well as destructive roles of astrocytes in the immature ischemic brain to stimulate further research into this unexplored aspect of brain pathophysiology.