Spectroscopic detection of brain propylene glycol in neonates: Effects of different pharmaceutical formulations of phenobarbital.

BACKGROUND: The first choice for treatment of neonatal convulsions is intravenous phenobarbital, which contains propylene glycol (PG) as a solvent. Although PG is generally considered safe, the dosage can exceed safety thresholds in neonates. High PG levels can cause lactic acidosis. PURPOSE/HYPOTHESIS: To investigate a relationship between brain PG concentration and medication administered to neonates, and to study if a correlation between spectroscopically detected PG and lactate was present. STUDY TYPE: Retrospective. POPULATION: Forty-one neonates who underwent MRI/MRS. FIELD STRENGTH/SEQUENCE: Short echo time single voxel MRS at 1.5T. ASSESSMENT: Spectra were quantified. Concentrations of PG were correlated with medication administered, because intravenously administered phenobarbital solutions contained 10, 25, or 50 mg phenobarbital per ml, all containing 350 mg PG per ml. The interval between medication and MRI/MRS was determined. STATISTICAL TESTS: Chi-square test, Student's t-test, Mann-Whitney U-test and Spearman correlation. RESULTS: Eighteen neonates had brain PG >1 mM (median 3.4 mM, maximum 9.5 mM). All 18 neonates with high brain PG and 14 neonates with low brain PG (<1 mM) received phenobarbital as the only source of PG. Nine neonates did not receive any phenobarbital/PG-containing medication. Neonates with high brain PG more often received 10 mg/ml phenobarbital, resulting in higher PG dose (high vs. low brain PG (median [interquartile range]: 1400 [595] vs. 350 [595] mg/kg, respectively, P < 0.01). In addition, the interval between the last phenobarbital dose and MRI was shorter in the high brain PG group (high vs. low brain PG: 16 [21] vs. 95 [83] hours, respectively, P < 0.001). Within neonates that received phenobarbital, there was no conclusive correlation between spectroscopically detected PG and lactate (Spearman's rho = 0.23, P = 0.10). DATA CONCLUSION: These MRS findings may increase awareness of potentially toxic PG concentrations in the neonatal brain due to intravenous phenobarbital administration and its dependence on the phenobarbital formulation used. LEVEL OF EVIDENCE: 4 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2019;49:1062-1068.

Evaluation of a System-Specific Function To Describe the Pharmacokinetics of Benzylpenicillin in Term Neonates Undergoing Moderate Hypothermia.

The pharmacokinetic (PK) properties of intravenous (i.v.) benzylpenicillin in term neonates undergoing moderate hypothermia after perinatal asphyxia were evaluated, as they have been unknown until now. A system-specific modeling approach was applied, in which our recently developed covariate model describing developmental and temperature-induced changes in amoxicillin clearance (CL) in the same patient study population was incorporated into a population PK model of benzylpenicillin with a priori birthweight (BW)-based allometric scaling. Pediatric population covariate models describing the developmental changes in drug elimination may constitute system-specific information and may therefore be incorporated into PK models of drugs cleared through the same pathway. The performance of this system-specific model was compared to that of a reference model. Furthermore, Monte-Carlo simulations were performed to evaluate the optimal dose. The system-specific model performed as well as the reference model. Significant correlations were found between CL and postnatal age (PNA), gestational age (GA), body temperature (TEMP), urine output (UO; system-specific model), and multiorgan failure (reference model). For a typical patient with a GA of 40 weeks, BW of 3,000 g, PNA of 2 days (TEMP, 33.5°C), and normal UO (2 ml/kg/h), benzylpenicillin CL was 0.48 liter/h (interindividual variability [IIV] of 49%) and the volume of distribution of the central compartment was 0.62 liter/kg (IIV of 53%) in the system-specific model. Based on simulations, we advise a benzylpenicillin i.v. dose regimen of 75,000 IU/kg/day every 8 h (q8h), 150,000 IU/kg/day q8h, and 200,000 IU/kg/day q6h for patients with GAs of 36 to 37 weeks, 38 to 41 weeks, and ≥42 weeks, respectively. The system-specific model may be used for other drugs cleared through the same pathway accelerating model development.

Altered gentamicin pharmacokinetics in term neonates undergoing controlled hypothermia.

AIM(S): Little is known about the pharmacokinetic (PK) properties of gentamicin in newborns undergoing controlled hypothermia after suffering from hypoxic−ischaemic encephalopathy due to perinatal asphyxia. This study prospectively evaluates and describes the population PK of gentamicin in these patients METHODS: Demographic, clinical and laboratory data of patients included in a multicentre prospective observational cohort study (the 'PharmaCool Study') were collected. A non-linear mixed-effects regression analysis (nonmem®) was performed to describe the population PK of gentamicin. The most optimal dosing regimen was evaluated based on simulations of the final model. RESULTS: A total of 47 patients receiving gentamicin were included in the analysis. The PK were best described by an allometric two compartment model with gestational age (GA) as a covariate on clearance (CL). During hypothermia the CL of a typical patient (3 kg, GA 40 weeks, 2 days post-natal age (PNA)) was 0.06 l kg−1 h−1 (inter-individual variability (IIV) 26.6%) and volume of distribution of the central compartment (Vc) was 0.46 l kg−1 (IIV 40.8%). CL was constant during hypothermia and rewarming, but increased by 29% after reaching normothermia (>96 h PNA). CONCLUSIONS: This study describes the PK of gentamicin in neonates undergoing controlled hypothermia. The 29% higher CL in the normothermic phase compared with the preceding phases suggests a delay in normalization of CL after rewarming has occurred. Based on simulations we recommend an empiric dose of 5 mg kg−1 every 36 h or every 24 h for patients with GA 36­40 weeks and GA 42 weeks, respectively.

Physiological-based cord clamping in very preterm infants: the Aeration, Breathing, Clamping 3 (ABC3) trial-statistical analysis plan for a multicenter randomized controlled trial.

BACKGROUND: Mortality, cerebral injury, and necrotizing enterocolitis (NEC) are common complications of very preterm birth. An important risk factor for these complications is hemodynamic instability. Pre-clinical studies suggest that the timing of umbilical cord clamping affects hemodynamic stability during transition. Standard care is time-based cord clamping (TBCC), with clamping irrespective of lung aeration. It is unknown whether delaying cord clamping until lung aeration and ventilation have been established (physiological-based cord clamping, PBCC) is more beneficial. This document describes the statistical analyses for the ABC3 trial, which aims to assess the efficacy and safety of PBCC, compared to TBCC. METHODS: The ABC3 trial is a multicenter, randomized trial investigating PBCC (intervention) versus TBCC (control) in very preterm infants. The trial is ethically approved. Preterm infants born before 30 weeks of gestation are randomized after parental informed consent. The primary outcome is intact survival, defined as the composite of survival without major cerebral injury and/or NEC. Secondary short-term outcomes are co-morbidities and adverse events assessed during NICU admission, parental reported outcomes, and long-term neurodevelopmental outcomes assessed at a corrected age of 2 years. To test the hypothesis that PBCC increases intact survival, a logistic regression model will be estimated using generalized estimating equations (accounting for correlation between siblings and observations in the same center) with treatment and gestational age as predictors. This plan is written and submitted without knowledge of the data. DISCUSSION: The findings of this trial will provide evidence for future clinical guidelines on optimal cord clamping management at birth. TRIAL REGISTRATION: ClinicalTrials.gov NCT03808051. Registered on 17 January 2019.

Short-term pulmonary and systemic effects of hydrocortisone initiated 7-14 days after birth in ventilated very preterm infants: a secondary analysis of a randomised controlled trial.

OBJECTIVE: Observational studies in preterm infants suggest that systemic hydrocortisone improves pulmonary condition but may also lead to systemic adverse effects. We report the short-term pulmonary and systemic effects of hydrocortisone initiated in the second week. DESIGN: Randomised placebo-controlled trial. SETTING: Dutch and Belgian neonatal intensive care units. PATIENTS: Infants born <30 weeks' gestation and/or birth weight <1250 g, and ventilator dependent in the second week of life. INTERVENTION: Infants were randomly assigned to a 22-day course of systemic hydrocortisone (cumulative dose 72.5 mg/kg; n=182) or placebo (n=190). MAIN OUTCOME MEASURES: Data on extubation, ventilator settings, glucose levels, and blood pressure were recorded daily and analysed during the first 7 days of treatment using linear mixed-effects models. RESULTS: Infants in the hydrocortisone group (24.3%) failed extubation less often compared with placebo (38.6%, crude risk difference: -14.3% (95% CI: -23.4% to -4.8%)). The estimated difference in daily rate of change between hydrocortisone and placebo was -0.42 cmH2O (95% CI: -0.48 to -0.36) for mean airway pressure, -0.02 (95% CI: -0.02 to -0.01) for fraction of inspired oxygen, -0.37 (95% CI: -0.44 to -0.30) for respiratory index, 0.14 mmol/L (95% CI: 0.08 to 0.21) for blood glucose levels and 0.83 mm Hg (95% CI: 0.58 to 1.09) for mean blood pressure. CONCLUSIONS: Systemic hydrocortisone initiated between 7 and 14 days after birth in ventilated preterm infants improves pulmonary condition, thereby facilitating weaning and extubation from invasive ventilation. The effects of hydrocortisone on blood glucose levels and blood pressure were mild and of limited clinical relevance. TRIAL REGISTRATION NUMBER: Netherlands Trial Register (NTR2768; https://www.trialregister.nl/trial/2640) and European Union Clinical Trials Register (EudraCT, 2010-023777-19).

Doxapram versus placebo in preterm newborns: a study protocol for an international double blinded multicentre randomized controlled trial (DOXA-trial).

BACKGROUND: Apnoea of prematurity (AOP) is one of the most common diagnoses among preterm infants. AOP often leads to hypoxemia and bradycardia which are associated with an increased risk of death or disability. In addition to caffeine therapy and non-invasive respiratory support, doxapram might be used to reduce hypoxemic episodes and the need for invasive mechanical ventilation in preterm infants, thereby possibly improving their long-term outcome. However, high-quality trials on doxapram are lacking. The DOXA-trial therefore aims to investigate the safety and efficacy of doxapram compared to placebo in reducing the composite outcome of death or severe disability at 18 to 24 months corrected age. METHODS: The DOXA-trial is a double blinded, multicentre, randomized, placebo-controlled trial conducted in the Netherlands, Belgium and Canada. A total of 396 preterm infants with a gestational age below 29 weeks, suffering from AOP unresponsive to non-invasive respiratory support and caffeine will be randomized to receive doxapram therapy or placebo. The primary outcome is death or severe disability, defined as cognitive delay, cerebral palsy, severe hearing loss, or bilateral blindness, at 18-24 months corrected age. Secondary outcomes are short-term neonatal morbidity, including duration of mechanical ventilation, bronchopulmonary dysplasia and necrotising enterocolitis, hospital mortality, adverse effects, pharmacokinetics and cost-effectiveness. Analysis will be on an intention-to-treat principle. DISCUSSION: Doxapram has the potential to improve neonatal outcomes by improving respiration, but the safety concerns need to be weighed against the potential risks of invasive mechanical ventilation. It is unknown if the use of doxapram improves the long-term outcome. This forms the clinical equipoise of the current trial. This international, multicentre trial will provide the needed high-quality evidence on the efficacy and safety of doxapram in the treatment of AOP in preterm infants. TRIAL REGISTRATION: ClinicalTrials.gov NCT04430790 and EUDRACT 2019-003666-41. Prospectively registered on respectively June and January 2020.

Physiological-based cord clamping in very preterm infants: the Aeration, Breathing, Clamping 3 (ABC3) trial-study protocol for a multicentre randomised controlled trial.

BACKGROUND: International guidelines recommend delayed umbilical cord clamping (DCC) up to 1 min in preterm infants, unless the condition of the infant requires immediate resuscitation. However, clamping the cord prior to lung aeration may severely limit circulatory adaptation resulting in a reduction in cardiac output and hypoxia. Delaying cord clamping until lung aeration and ventilation have been established (physiological-based cord clamping, PBCC) allows for an adequately established pulmonary circulation and results in a more stable circulatory transition. The decline in cardiac output following time-based delayed cord clamping (TBCC) may thus be avoided. We hypothesise that PBCC, compared to TBCC, results in a more stable transition in very preterm infants, leading to improved clinical outcomes. The primary objective is to compare the effect of PBCC on intact survival with TBCC. METHODS: The Aeriation, Breathing, Clamping 3 (ABC3) trial is a multicentre randomised controlled clinical trial. In the interventional PBCC group, the umbilical cord is clamped after the infant is stabilised, defined as reaching heart rate > 100 bpm and SpO2 > 85% while using supplemental oxygen < 40%. In the control TBCC group, cord clamping is time based at 30-60 s. The primary outcome is survival without major cerebral and/or intestinal injury. Preterm infants born before 30 weeks of gestation are included after prenatal parental informed consent. The required sample size is 660 infants. DISCUSSION: The findings of this trial will provide evidence for future clinical guidelines on optimal cord clamping management in very preterm infants at birth. TRIAL REGISTRATION: ClinicalTrials.gov NCT03808051. First registered on January 17, 2019.

MR Spectroscopy Shows Long Propylene Glycol Half-Life in Neonatal Brain.

INTRODUCTION: Neonatal propylene glycol (PG) clearance is low with long plasma half-life. We hypothesized that neonatal brain PG clearance is diminished and may be related to perinatal asphyxia, infection, or stroke, via different blood-brain barrier permeability. This study aimed to estimate cerebral PG half-life with a clearance model including PG measured with MR spectroscopy (MRS) in neonates that received phenobarbital as the only PG source and to evaluate whether PG clearance was related to intracerebral pathology, for example, perinatal asphyxia, infection, or stroke. METHODS: In this retrospective cohort study, 45 neonates receiving any dose of phenobarbital underwent MRS (short echo time single-voxel MRS at 1.5 T). Cumulative phenobarbital/PG doses were calculated. MRS indications were perinatal asphyxia (n = 22), infection (n = 4), stroke (n = 10), metabolic disease (n = 4), and others (n = 5). RESULTS: Medians (interquartile range) included gestational age 39.4 (3.1) weeks, birth weight 3,146 (1,340) g, and cumulative PG dose 700 (1,120) mg/kg. First-order kinetics with mono-exponential decay showed cerebral PG half-life of 40.7 h and volume of distribution of 1.6 L/kg. Zero-order kinetics showed a rate constant of 0.048 mM/h and a volume of distribution of 2.3 L/kg, but the fit had larger residuals than the first-order model. There were no differences in ΔPG (i.e., PG estimated with clearance model minus PG observed with MRS) in infants with perinatal asphyxia, infection, or stroke. DISCUSSION/CONCLUSION: This study showed a long cerebral PG half-life of 40.7 h in neonates, unrelated to perinatal asphyxia, infection, or stroke. These findings should increase awareness of possible toxic PG concentrations in neonatal brain due to intravenous PG-containing drugs.

The prognostic value of NIRS in preterm infants with (suspected) late-onset sepsis in relation to long term outcome: A pilot study.

Late-onset sepsis is frequently seen in preterm infants and is associated with poor neurodevelopmental outcome. White matter damage is proposed as substrate of poor outcome, with contributing factors as regional hypoxia and effects of cytokines on oligodendrocytes. We investigated the relation between cerebral oxygenation during (suspected) late-onset sepsis and neurodevelopmental outcome. Prospective cohort study, including preterm infants (gestational age <32 weeks and/or birthweight <1500 grams) with (suspected) late-onset sepsis underwent NIRS registration during the first 72 hours of suspected late-onset sepsis. At two years corrected age neurodevelopment was scored using the Bayley Scales of Infant Development-II. Thirty-two infants were included. Twenty-seven infants were identified with proven late-onset sepsis and five infants had clinical sepsis without positive blood culture. In this study, late-onset sepsis was predominantly caused by coagulase negative staphylococci (CoNS) (72%). All NIRS values were within normal limits. No association was found between NIRS and impaired neurodevelopmental outcome (n = 4) at corrected age two years: composite cognitive score 105 (80-115), composite motor score 103 (82-118) (median and range). In this pilot study, late-onset sepsis (predominantly caused by CoNS with a relatively mild clinical course), was not associated with aberrant NIRS values, nor with impaired neurodevelopmental outcome. Further research might establish our findings and elucidate effects of other micro-organisms on cerebral perfusion.

Outcome of Infants with Therapeutic Hypothermia after Perinatal Asphyxia and Early-Onset Sepsis.

BACKGROUND: Animal models suggest that neuroprotective effects of therapeutic hypothermia (TH) after perinatal asphyxia are reduced in infants with early-onset sepsis. OBJECTIVES: To assess the outcome of infants with perinatal asphyxia, neonatal encephalopathy, and TH in the presence of early-onset sepsis. METHODS: In a retrospective cohort of 1,084 infants with perinatal asphyxia and TH, the outcome of 42 infants (gestational age 36.1-42.6 weeks and birth weight 2,280-5,240 g) with proven sepsis (n = 14) and probable sepsis (n = 28) was analyzed. Death, cerebral palsy, or a delayed development at 2 years was considered an adverse outcome. RESULTS: Sepsis was caused mostly by group B streptococci (n = 17), other Gram-positive bacteria (n = 5), and Candida albicans (n = 1). Of the 42 infants, 9 (21.4%) died, and 5 (11.9%) showed impairments on follow-up. The outcome is comparable to the previously reported outcome of infants with TH without early-onset sepsis. CONCLUSION: A good outcome was reported in the majority of infants with perinatal asphyxia, TH, and early-onset sepsis. Cooling should not be withheld from these infants.

Pharmacokinetics of morphine in encephalopathic neonates treated with therapeutic hypothermia.

OBJECTIVE: Morphine is a commonly used drug in encephalopathic neonates treated with therapeutic hypothermia after perinatal asphyxia. Pharmacokinetics and optimal dosing of morphine in this population are largely unknown. The objective of this study was to describe pharmacokinetics of morphine and its metabolites morphine-3-glucuronide and morphine-6-glucuronide in encephalopathic neonates treated with therapeutic hypothermia and to develop pharmacokinetics based dosing guidelines for this population. STUDY DESIGN: Term and near-term encephalopathic neonates treated with therapeutic hypothermia and receiving morphine were included in two multicenter cohort studies between 2008-2010 (SHIVER) and 2010-2014 (PharmaCool). Data were collected during hypothermia and rewarming, including blood samples for quantification of morphine and its metabolites. Parental informed consent was obtained for all participants. RESULTS: 244 patients (GA mean (sd) 39.8 (1.6) weeks, BW mean (sd) 3,428 (613) g, male 61.5%) were included. Morphine clearance was reduced under hypothermia (33.5°C) by 6.89%/°C (95% CI 5.37%/°C- 8.41%/°C, p<0.001) and metabolite clearance by 4.91%/°C (95% CI 3.53%/°C- 6.22%/°C, p<0.001) compared to normothermia (36.5°C). Simulations showed that a loading dose of 50 µg/kg followed by continuous infusion of 5 µg/kg/h resulted in morphine plasma concentrations in the desired range (between 10 and 40 µg/L) during hypothermia. CONCLUSIONS: Clearance of morphine and its metabolites in neonates is affected by therapeutic hypothermia. The regimen suggested by the simulations will be sufficient in the majority of patients. However, due to the large interpatient variability a higher dose might be necessary in individual patients to achieve the desired effect. TRIAL REGISTRATION: www.trialregister.nl NTR2529.

Phenobarbital, Midazolam Pharmacokinetics, Effectiveness, and Drug-Drug Interaction in Asphyxiated Neonates Undergoing Therapeutic Hypothermia.

BACKGROUND: Phenobarbital and midazolam are commonly used drugs in (near-)term neonates treated with therapeutic hypothermia for hypoxic-ischaemic encephalopathy, for sedation, and/or as anti-epileptic drug. Phenobarbital is an inducer of cytochrome P450 (CYP) 3A, while midazolam is a CYP3A substrate. Therefore, co-treatment with phenobarbital might impact midazolam clearance. OBJECTIVES: To assess pharmacokinetics and clinical anti-epileptic effectiveness of phenobarbital and midazolam in asphyxiated neonates and to develop dosing guidelines. METHODS: Data were collected in the prospective multicentre PharmaCool study. In the present study, neonates treated with therapeutic hypothermia and receiving midazolam and/or phenobarbital were included. Plasma concentrations of phenobarbital and midazolam including its metabolites were determined in blood samples drawn on days 2-5 after birth. Pharmacokinetic analyses were performed using non-linear mixed effects modelling; clinical effectiveness was defined as no use of additional anti-epileptic drugs. RESULTS: Data were available from 113 (phenobarbital) and 118 (midazolam) neonates; 68 were treated with both medications. Only clearance of 1-hydroxy midazolam was influenced by hypothermia. Phenobarbital co-administration increased midazolam clearance by a factor 2.3 (95% CI 1.9-2.9, p < 0.05). Anticonvulsant effectiveness was 65.5% for phenobarbital and 37.1% for add-on midazolam. CONCLUSIONS: Therapeutic hypothermia does not influence clearance of phenobarbital or midazolam in (near-)term neonates with hypoxic-ischaemic encephalopathy. A phenobarbital dose of 30 mg/kg is advised to reach therapeutic concentrations. Phenobarbital co-administration significantly increased midazolam clearance. Should phenobarbital be substituted by non-CYP3A inducers as first-line anticonvulsant, a 50% lower midazolam maintenance dose might be appropriate to avoid excessive exposure during the first days after birth.

Severe Neonatal Anaemia, MRI Findings and Neurodevelopmental Outcome.

BACKGROUND AND OBJECTIVE: Severe neonatal anaemia can impair cerebral oxygen supply. Data on long-term outcomes following severe neonatal anaemia are scarce. METHODS: Clinical data and neurodevelopmental outcome of 49 (near) term infants with haemoglobin concentration after birth <6.0 mmol/l were retrospectively collected and analysed. In a subgroup of 28 patients, amplitude-integrated EEG was available and in 25 infants cerebral MRI was obtained. Infants were followed up at 14-35 months of age and assessed with the Griffiths Scale of Mental Development or Bayley Scale of Infant Development. RESULTS: Eighteen patients (37%) died during the neonatal period. In 25 patients MRI was performed. A predominant pattern of injury on MRI was seen in the basal ganglia and thalami in 7 patients (28%), whereas some form of white matter injury was present in 16 (64%) and a combination in 3 (12%). Follow-up data were available for 26 patients (84% of survivors). Formal assessment of neurodevelopmental outcome was performed in 20 of 31 (65%) infants who survived (median age: 19 months, range: 14-35). Sixteen infants (80%) had a developmental quotient appropriate for age in the first 2 years after birth. On motor outcome, 1 patient (5%) scored below average (Z-score -1.10). One patient developed cerebral palsy. CONCLUSION: Early neurodevelopmental outcome in surviving patients with severe neonatal anaemia was within the normal range in the majority of the survivors. MRI showed mild-to-moderate white matter injury in two thirds of the infants. Prospectively collected data with a longer follow-up period are needed.

Introduction of hypothermia for neonates with perinatal asphyxia in the Netherlands and Flanders.

BACKGROUND: Therapeutic hypothermia was introduced in the Netherlands and Flanders, Belgium, in 2008. Since then, an increasing number of patients has been treated - up to 166 in 2010. Complications and outcome were registered in an online database. OBJECTIVES: The aim of this study was to analyse complications and outcome after implementation. METHODS: Data were retrieved from an online database to which all centres had contributed. RESULTS: In 3 years, 332 patients were treated. Excluding 24 patients with congenital abnormalities or metabolic disorders, mortality was 31.8%. Of the 210 survivors without congenital malformations, 21 had cerebral palsy, another 19 a developmental delay of more than 3 months at the age of at least 24 months, and 2 had severe hearing loss. The total adverse outcome, combining death and adverse neurodevelopment, in 308 patients without congenital malformations is 45.5%, which is similar to that of the large trials. CONCLUSIONS: The introduction of therapeutic hypothermia for neonates with perinatal asphyxia in the Netherlands and Flanders has been rapid and successful, with results similar to findings in the randomised controlled trials.