Placebo-controlled trial of midazolam sedation in mechanically ventilated newborn babies

The Use of Midazolam as an Antiseizure Medication in Neonatal Seizures: Single Center Experience and Literature Review

BACKGROUND

Existing therapeutic alternatives for neonatal crises have expanded in recent decades, but no consensus has been reached on protocols based on neonatal seizures. In particular, little is known about the use of midazolam in newborns.

AIM

The aim of our study is to evaluate the response to midazolam, the appearance of side effects, and their impact on therapeutic decisions.

METHODS

This is a STROBE-conformed retrospective observational study of 10 patients with neonatal seizures unresponsive to common antiseizure drugs, admitted to San Marco University Hospital's neonatal intensive care (Catania, Italy) from September 2015 to October 2022. In our database search, 36 newborns were treated with midazolam, but only ten children met the selection criteria for this study.

RESULTS

Response was assessed both clinically and electrographic. Only 4 patients at the end of the treatment showed a complete electroclinical response; they were full-term infants with a postnatal age greater than 7 days. Non-responders and partial responders are all premature (4/10) or full-term neonates who started therapy in the first days of life (< 7th day) (2/10).

CONCLUSION

Neonatal seizures in preterm show a lower response rate to midazolam than seizures in full-term infants, with poorer prognosis. Liver and renal function and central nervous system development are incomplete in premature infants and the first days of life. In this study, we show that midazolam, a short-acting benzodiazepine, appears to be most effective in full-term infants and after 7 days of life.

Pharmacological pain and sedation interventions for the prevention of intraventricular hemorrhage in preterm infants on assisted ventilation - an overview of systematic reviews

BACKGROUND

Germinal matrix hemorrhage and intraventricular hemorrhage (GMH-IVH) may contribute to neonatal morbidity and mortality and result in long-term neurodevelopmental sequelae. Appropriate pain and sedation management in ventilated preterm infants may decrease the risk of GMH-IVH; however, it might be associated with harms.

OBJECTIVES

To summarize the evidence from systematic reviews regarding the effects and safety of pharmacological interventions related to pain and sedation management in order to prevent GMH-IVH in ventilated preterm infants.

METHODS

We searched the Cochrane Library August 2022 for reviews on pharmacological interventions for pain and sedation management to prevent GMH-IVH in ventilated preterm infants (< 37 weeks' gestation). We included Cochrane Reviews assessing the following interventions administered within the first week of life: benzodiazepines, paracetamol, opioids, ibuprofen, anesthetics, barbiturates, and antiadrenergics. Primary outcomes were any GMH-IVH (aGMH-IVH), severe IVH (sIVH), all-cause neonatal death (ACND), and major neurodevelopmental disability (MND). We assessed the methodological quality of included reviews using the AMSTAR-2 tool. We used GRADE to assess the certainty of evidence.

MAIN RESULTS

We included seven Cochrane Reviews and one Cochrane Review protocol. The reviews on clonidine and paracetamol did not include randomized controlled trials (RCTs) matching our inclusion criteria. We included 40 RCTs (3791 infants) from reviews on paracetamol for patent ductus arteriosus (3), midazolam (3), phenobarbital (9), opioids (20), and ibuprofen (5). The quality of the included reviews was high. The certainty of the evidence was moderate to very low, because of serious imprecision and study limitations. Germinal matrix hemorrhage-intraventricular hemorrhage (any grade) Compared to placebo or no intervention, the evidence is very uncertain about the effects of paracetamol on aGMH-IVH (risk ratio (RR) 0.89, 95% confidence interval (CI) 0.38 to 2.07; 2 RCTs, 82 infants; very low-certainty evidence); midazolam may result in little to no difference in the incidence of aGMH-IVH (RR 1.68, 95% CI 0.87 to 3.24; 3 RCTs, 122 infants; low-certainty evidence); the evidence is very uncertain about the effect of phenobarbital on aGMH-IVH (RR 0.99, 95% CI 0.83 to 1.19; 9 RCTs, 732 infants; very low-certainty evidence); opioids may result in little to no difference in aGMH-IVH (RR 0.85, 95% CI 0.65 to 1.12; 7 RCTs, 469 infants; low-certainty evidence); ibuprofen likely results in little to no difference in aGMH-IVH (RR 0.99, 95% CI 0.81 to 1.21; 4 RCTs, 759 infants; moderate-certainty evidence). Compared to ibuprofen, the evidence is very uncertain about the effects of paracetamol on aGMH-IVH (RR 1.17, 95% CI 0.31 to 4.34; 1 RCT, 30 infants; very low-certainty evidence). Compared to midazolam, morphine may result in a reduction in aGMH-IVH (RR 0.28, 95% CI 0.09 to 0.87; 1 RCT, 46 infants; low-certainty evidence). Compared to diamorphine, the evidence is very uncertain about the effect of morphine on aGMH-IVH (RR 0.65, 95% CI 0.40 to 1.07; 1 RCT, 88 infants; very low-certainty evidence). Severe intraventricular hemorrhage (grade 3 to 4) Compared to placebo or no intervention, the evidence is very uncertain about the effect of paracetamol on sIVH (RR 1.80, 95% CI 0.43 to 7.49; 2 RCTs, 82 infants; very low-certainty evidence) and of phenobarbital (grade 3 to 4) (RR 0.91, 95% CI 0.66 to 1.25; 9 RCTs, 732 infants; very low-certainty evidence); opioids may result in little to no difference in sIVH (grade 3 to 4) (RR 0.98, 95% CI 0.71 to 1.34; 6 RCTs, 1299 infants; low-certainty evidence); ibuprofen may result in little to no difference in sIVH (grade 3 to 4) (RR 0.82, 95% CI 0.54 to 1.26; 4 RCTs, 747 infants; low-certainty evidence). No studies on midazolam reported this outcome. Compared to ibuprofen, the evidence is very uncertain about the effects of paracetamol on sIVH (RR 2.65, 95% CI 0.12 to 60.21; 1 RCT, 30 infants; very low-certainty evidence). Compared to midazolam, the evidence is very uncertain about the effect of morphine on sIVH (grade 3 to 4) (RR 0.08, 95% CI 0.00 to 1.43; 1 RCT, 46 infants; very low-certainty evidence). Compared to fentanyl, the evidence is very uncertain about the effect of morphine on sIVH (grade 3 to 4) (RR 0.59, 95% CI 0.18 to 1.95; 1 RCT, 163 infants; very low-certainty evidence). All-cause neonatal death Compared to placebo or no intervention, the evidence is very uncertain about the effect of phenobarbital on ACND (RR 0.94, 95% CI 0.51 to 1.72; 3 RCTs, 203 infants; very low-certainty evidence); opioids likely result in little to no difference in ACND (RR 1.12, 95% CI 0.80 to 1.55; 5 RCTs, 1189 infants; moderate-certainty evidence); the evidence is very uncertain about the effect of ibuprofen on ACND (RR 1.00, 95% CI 0.38 to 2.64; 2 RCTs, 112 infants; very low-certainty evidence). Compared to midazolam, the evidence is very uncertain about the effect of morphine on ACND (RR 0.31, 95% CI 0.01 to 7.16; 1 RCT, 46 infants; very low-certainty evidence). Compared to diamorphine, the evidence is very uncertain about the effect of morphine on ACND (RR 1.17, 95% CI 0.43 to 3.19; 1 RCT, 88 infants; very low-certainty evidence). Major neurodevelopmental disability Compared to placebo, the evidence is very uncertain about the effect of opioids on MND at 18 to 24 months (RR 2.00, 95% CI 0.39 to 10.29; 1 RCT, 78 infants; very low-certainty evidence) and at five to six years (RR 1.6, 95% CI 0.56 to 4.56; 1 RCT, 95 infants; very low-certainty evidence). No studies on other drugs reported this outcome.

AUTHORS' CONCLUSIONS

None of the reported studies had an impact on aGMH-IVH, sIVH, ACND, or MND. The certainty of the evidence ranged from moderate to very low. Large RCTs of rigorous methodology are needed to achieve an optimal information size to assess the effects of pharmacological interventions for pain and sedation management for the prevention of GMH-IVH and mortality in preterm infants. Studies might compare interventions against either placebo or other drugs. Reporting of the outcome data should include the assessment of GMH-IVH and long-term neurodevelopment.

Pharmacologic Analgesia and Sedation in Neonates

Chronic pain and agitation in neonatal life impact the developing brain. Oral sweet-tasting solutions should be used judiciously to mitigate behavioral responses to mild painful procedures, keeping in mind that the long-term impact is unknown. Rapidly acting opioids should be used as part of premedication cocktails for nonemergent endotracheal intubations. Continuous low-dose morphine or dexmedetomidine may be considered for preterm or term neonates exhibiting signs of stress during mechanical ventilation and therapeutic hypothermia, respectively. Further research is required regarding the pharmacokinetics, pharmacodynamics, safety, and efficacy of pharmacologic agents used to mitigate mild, moderate, and chronic pain and stress in neonates.

Preterm Physiologically Based Pharmacokinetic Model. Part II: Applications of the Model to Predict Drug Pharmacokinetics in the Preterm Population

BACKGROUND

Preterm neonates are usually not part of a traditional drug development programme, however they are frequently administered medicines. Developing modelling and simulation tools, such as physiologically based pharmacokinetic (PBPK) models that incorporate developmental physiology and maturation of drug metabolism, can be used to predict drug exposure in this group of patients, and may help to optimize drug dose adjustment.

OBJECTIVE

The aim of this study was to assess and verify the predictability of a preterm PBPK model using compounds that undergo diverse renal and/or hepatic clearance based on the knowledge of their disposition in adults.

METHODS

A PBPK model was developed in the Simcyp Simulator V17 to predict the pharmacokinetics (PK) of drugs in preterm neonates. Drug parameters for alfentanil, midazolam, caffeine, ibuprofen, gentamicin and vancomycin were collated from the literature. Predicted PK parameters and profiles were compared against the observed data.

RESULTS

The preterm PBPK model predicted the PK changes of the six compounds using ontogeny functions for cytochrome P450 (CYP) 1A2, CYP2C9 and CYP3A4 after oral and intravenous administrations. For gentamicin and vancomycin, the maturation of renal function was able to predict the exposure of these two compounds after intravenous administration. All PK parameter predictions were within a twofold error criteria.

CONCLUSION

While the developed preterm model for the prediction of PK behaviour in preterm patients is not intended to replace clinical studies, it can potentially help with deciding on first-time dosing in this population and study design in the absence of clinical data.

Maturation of midazolam clearance in critically ill children with severe bronchiolitis: A population pharmacokinetic analysis

PURPOSE

The aim of the present study was to develop a population pharmacokinetic model of midazolam, and to evaluate the influence of maturation process and other variability factors in critically ill children with severe acute bronchiolitis, who received a long-term intravenous infusion of midazolam.

METHODS

In the study were included 49 critically ill children of both genders (from 0 to 130 weeks of age) with severe acute bronchiolitis hospitalised in intensive care units. Nonlinear mixed effects modelling approach was applied for data analyses and simulations.

RESULTS

The final model is a two-compartment model that includes the effects of body weight using allometric scaling with fixed exponents and maturation of clearance. For a typical subject, scaled to the adult body weight of 70 kg, population pharmacokinetic values were estimated at 8.52 L/h for clearance (when maturation function was 1), 25.5 L/h for intercompartmental clearance, and 5.71 L and 39.8 L for the volume of the central and peripheral compartment, respectively. Based on the final model, maturation reaches 50% of the adult clearance in 45.9 weeks of postmenstrual age. The influence of gender, ABCB1 genotype and biochemical parameters on midazolam clearance was not detected. Results of simulations indicate the need for reduced dosing in certain groups of patients in order to maintain plasma concentrations of midazolam within recommended values.

CONCLUSIONS

The developed population pharmacokinetic model can contribute to the dosing optimisation of midazolam, especially in critically ill children as it includes the influence of size and maturation of clearance, which are important parameters for achieving the desired plasma concentrations of midazolam.

Recently Registered Midazolam Doses for Preterm Neonates Do Not Lead to Equal Exposure: A Population Pharmacokinetic Model

Although midazolam is a frequently used sedative in neonatal intensive care units, its use in preterm neonates has been off-label. Recently, a new dosing advice for midazolam for sedation on intensive care units has been included in the label (0.03 mg/[kg·h] for preterm neonates <32 weeks and 0.06 mg/[kg·h] for neonates >32 weeks). Concentration-time data of a prospective multicenter study (29 patients, median gestational age 26.7 [range 24.0-31.1 weeks]) were combined with previously published data (26 patients, median gestational age 28.1 [range 26.3-33.6 weeks]), and a population pharmacokinetic model describing the maturation of midazolam pharmacokinetics was developed in NONMEM 7.3. Clearance was 73.7 mL/h for a neonate weighing 1.1 kg and changed nonlinearly with body weight (exponent 1.69). Volume of distribution increased linearly with body weight and was 1.03 L for a neonate weighing 1.1 kg. Simulations of the newly registered dosing show considerable differences in steady-state concentrations in preterm neonates. To reach similar steady-state concentrations of 400 µg/mL (±100 µg/mL), a dose of 0.03 mg/(kg·h) is adequate for neonates ≥1 kg and ≤2 kg but would have to be reduced to 0.02 mg/(kg·h) (-33%) in neonates <1 kg and increased to 0.04 mg/(kg·h) (+33%) in neonates weighing >2 kg and ≤2.5 kg. The impact of the observed differences in exposure is difficult to assess because no target concentrations have yet been defined for midazolam, but the current analysis shows that one should be cautious in giving dosage advice based on historical data with a lack of reliable pharmacokinetic and effect data.

Predicting CYP3A-mediated midazolam metabolism in critically ill neonates, infants, children and adults with inflammation and organ failure

AIMS

Inflammation and organ failure have been reported to have an impact on cytochrome P450 (CYP) 3A-mediated clearance of midazolam in critically ill children. Our aim was to evaluate a previously developed population pharmacokinetic model both in critically ill children and other populations, in order to allow the model to be used to guide dosing in clinical practice.

METHODS

The model was evaluated externally in 136 individuals, including (pre)term neonates, infants, children and adults (body weight 0.77-90 kg, C-reactive protein level 0.1-341 mg l^-1 and 0-4 failing organs) using graphical and numerical diagnostics.

RESULTS

The pharmacokinetic model predicted midazolam clearance and plasma concentrations without bias in postoperative or critically ill paediatric patients and term neonates [median prediction error (MPE) <30%]. Using the model for extrapolation resulted in well-predicted clearance values in critically ill and healthy adults (MPE <30%), while clearance in preterm neonates was over predicted (MPE >180%).

CONCLUSION

The recently published pharmacokinetic model for midazolam, quantifying the influence of maturation, inflammation and organ failure in children, yields unbiased clearance predictions and can therefore be used for dosing instructions in term neonates, children and adults with varying levels of critical illness, including healthy adults, but not for extrapolation to preterm neonates.

A framework and case studies for evaluation of enzyme ontogeny in children's health risk evaluation

Knowledge of the ontogeny of Phase I and Phase II metabolizing enzymes may be used to inform children's vulnerability based upon likely differences in internal dose from xenobiotic exposure. This might provide a qualitative assessment of toxicokinetic (TK) variability and uncertainty pertinent to early lifestages and help scope a more quantitative physiologically based toxicokinetic (PBTK) assessment. Although much is known regarding the ontogeny of metabolizing systems, this is not commonly utilized in scoping and problem formulation stage of human health risk evaluation. A framework is proposed for introducing this information into problem formulation which combines data on enzyme ontogeny and chemical-specific TK to explore potential child/adult differences in internal dose and whether such metabolic differences may be important factors in risk evaluation. The framework is illustrated with five case study chemicals, including some which are data rich and provide proof of concept, while others are data poor. Case studies for toluene and chlorpyrifos indicate potentially important child/adult TK differences while scoping for acetaminophen suggests enzyme ontogeny is unlikely to increase early-life risks. Scoping for trichloroethylene and aromatic amines indicates numerous ways that enzyme ontogeny may affect internal dose which necessitates further evaluation. PBTK modeling is a critical and feasible next step to further evaluate child-adult differences in internal dose for a number of these chemicals.

Clonidine for sedation and analgesia for neonates receiving mechanical ventilation

BACKGROUND

Although routine administration of pharmacologic sedation or analgesia during mechanical ventilation in preterm neonates is not recommended, its use in clinical practice remains common. Alpha-2 agonists, mainly clonidine and dexmedetomidine, are used as adjunctive (or alternative) sedative agents alongside opioids and benzodiazepines. Clonidine has not been systematically assessed for use in neonatal sedation during ventilation.

OBJECTIVES

To assess whether clonidine administered to term and preterm newborn infants receiving mechanical ventilation reduces morbidity and mortality rates. To compare the intervention versus placebo, no treatment, and dexmedetomidine; and to assess the safety of clonidine infusion for potential harms.To perform subgroup analyses according to gestational age; birth weight; administration method (infusion or bolus therapy); dose, duration, and route of clonidine administration; and pharmacologic sedation as a co-intervention.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 12) in the Cochrane Library, MEDLINE via PubMed (1966 to January 10, 2017), Embase (1980 to January 10, 2017), and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to January 10, 2017). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomized controlled trials and quasi-randomized trials.

SELECTION CRITERIA

We searched for randomized controlled trials, quasi-randomized controlled trials, and cluster trials comparing clonidine versus placebo, no treatment, or dexmedetomidine administered to term and preterm newborns receiving mechanical ventilation via an endotracheal tube.

DATA COLLECTION AND ANALYSIS

For the included trial, two review authors independently extracted data (e.g. number of participants, birth weight, gestational age, all-cause death during initial hospitalization, duration of respiratory support, sedation scale, duration of hospital stay) and assessed risk of bias (e.g. adequacy of randomization, blinding, completeness of follow-up). This review considered primary outcomes of all-cause neonatal death, all-cause death during initial hospitalization, and duration of mechanical ventilation in days.

MAIN RESULTS

One trial, which included 112 infants, met the inclusion criteria for this review. Term newborn infants on mechanical ventilation with the need for continuous analgesia and sedation with fentanyl and midazolam were eligible for enrollment during the first 96 hours of ventilation. Study authors administered clonidine 1 μg/kg/h or placebo on day 4 after intubation.We found no differences between the two groups in all-cause death during hospitalization (risk ratio [RR] 0.69, 95% confidence interval [CI] 0.12 to 3.98). The quality of the evidence supporting these findings is low owing to imprecision of the estimates (one study; few events). The median (interquartile range) duration of mechanical ventilation was 7.1 days (5.7 to 9.1 days) in the clonidine group and 5.8 days (4.9 to 7.9 days) in the placebo group, respectively (P = 0.070). Among secondary outcomes, we found no differences in terms of duration of stay in the intensive care unit. Sedation scale values (COMFORT) and analgesia scores (Hartwig) during the first 72 hours of infusion of study medication were lower in the clonidine group than in the placebo group.

AUTHORS' CONCLUSIONS

At present, evidence is insufficient to show the efficacy and safety of clonidine for sedation and analgesia in term and preterm newborn infants receiving mechanical ventilation.

Intravenous midazolam infusion for sedation of infants in the neonatal intensive care unit

BACKGROUND

Proper sedation for neonates undergoing uncomfortable procedures may reduce stress and avoid complications. Midazolam is a short-acting benzodiazepine that is used increasingly in neonatal intensive care units (NICUs). However, its effectiveness as a sedative in neonates has not been systematically evaluated.

OBJECTIVES

Primary objeciveTo assess the effectiveness of intravenous midazolam infusion for sedation, as evaluated by behavioural and/or physiological measurements of sedation levels, in critically ill neonates in the NICU. Secondary objectivesTo assess effects of intravenous midazolam infusion for sedation on complications including the following.1. Incidence of intraventricular haemorrhage (IVH)/periventricular leukomalacia (PVL).2. Mortality.3. Occurrence of adverse effects associated with the use of midazolam (hypotension, neurological abnormalities).4. Days of ventilation.5. Days of supplemental oxygen.6. Incidence of pneumothorax.7. Length of NICU stay (days).8. Long-term neurodevelopmental outcomes.

SELECTION CRITERIA

We selected for review randomised and quasi-randomised controlled trials of intravenous midazolam infusion for sedation in infants aged 28 days or younger.

DATA COLLECTION AND ANALYSIS

We abstracted data regarding the primary outcome of level of sedation. We assessed secondary outcomes such as intraventricular haemorrhage, periventricular leukomalacia, death, length of NICU stay and adverse effects associated with midazolam. When appropriate, we performed meta-analyses using risk ratios (RRs) and risk differences (RDs), and if the RD was statistically significant, we calculated the number needed to treat for an additional beneficial outcome (NNTB) or an additional harmful outcome (NNTH), along with their 95% confidence intervals (95% CIs) for categorical variables, and weighted mean differences (WMDs) for continuous variables. We assessed heterogeneity by performing the I-squared (I2) test.

MAIN RESULTS

We included in the review three trials enrolling 148 neonates. We identified no new trials for this update. Using different sedation scales, each study showed a statistically significantly higher sedation level in the midazolam group compared with the placebo group. However, none of the sedation scales used have been validated in preterm infants; therefore, we could not ascertain the effectiveness of midazolam in this population. Duration of NICU stay was significantly longer in the midazolam group than in the placebo group (WMD 5.4 days, 95% CI 0.40 to 10.5; I2 = 0%; two studies, 89 infants). One study (43 infants) reported significantly lower Premature Infant Pain Profile (PIPP) scores during midazolam infusion than during dextrose (placebo) infusion (MD -3.80, 95% CI -5.93 to -1.67). Another study (46 infants) observed a higher incidence of adverse neurological events at 28 days' postnatal age (death, grade III or IV IVH or PVL) in the midazolam group compared with the morphine group (RR 7.64, 95% CI 1.02 to 57.21; RD 0.28, 95% CI 0.07 to 0.49; NNTH 4, 95% CI 2 to 14) (tests for heterogeneity not applicable). We considered these trials to be of moderate quality according to GRADE assessment based on the following outcomes: mortality during hospital stay, length of NICU stay, adequacy of analgesia according to PIPP scores and poor neurological outcomes by 28 days' postnatal age.

AUTHORS' CONCLUSIONS

Data are insufficient to promote the use of intravenous midazolam infusion as a sedative for neonates undergoing intensive care. This review raises concerns about the safety of midazolam in neonates. Further research on the effectiveness and safety of midazolam in neonates is needed.

Narcotics and Sedative Use in Preterm Neonates

OBJECTIVES

To evaluate patterns of narcotic and sedative use in neonatal intensive care units (NICUs) across Canada using data collected by the Canadian Neonatal Network.

STUDY DESIGN

We conducted a retrospective observational cohort study of preterm neonates at <33 weeks' gestation and admitted to a participating Canadian Neonatal Network NICU. The proportion of all neonates who received sedative(s), narcotic(s), or either sedative(s), narcotic(s), or both during their NICU stay was calculated for each year. Because opioids are used for premedication before intubation, only continuous infusions of a narcotic drug were included. Variation in narcotics and sedative usage between sites in 2014 was determined using logistic regression analysis, with adjustment for gestational age, surgery, and mechanical ventilation.

RESULTS

Of 20 744 neonates, 29% of neonates received a narcotic, a sedative, or both; 23% received a narcotic and 17% a sedative. Although no clinically significant changes in drug exposure were documented during the 5-year period, there were statistically significant differences in narcotic and sedative use between sites, ranging from 3% to 41% for narcotic and 2% to 48% for sedative use (aORs 0.2-5.7 and 0.1-15, respectively, P < .05).

CONCLUSIONS

Exposure to narcotic or sedative agents is highly variable in preterm neonates across Canada despite concerns of adverse outcomes associated with these drugs. The tremendous variation in practice suggests that further research on their current usage, as well as identifying optimal practice procedures is warranted.

Efficacy of α2-Agonists for Sedation in Pediatric Critical Care: A Systematic Review

OBJECTIVE

Children in PICUs normally require analgesics and sedatives to maintain comfort, safety, and cooperation with interventions. α2-agonists (clonidine and dexmedetomidine) have been described as adjunctive (or alternative) sedative agents alongside opioids and benzodiazepines. This systematic review aimed to determine whether α2-agonists were effective in maintaining patients at a target sedation score over time compared with a comparator group. We also aimed to determine whether concurrent use of α2-agonists provided opioid-sparing effects.

DATA SOURCES

A systematic search was performed using the Cochrane Central Register of Controlled Trials, PubMed, EMBASE, CINAHL, and LILACS.

STUDY SELECTION

We included randomized controlled trials of children in PICU treated with clonidine or dexmedetomidine for the indication of sedation.

DATA EXTRACTION

Two authors independently screened articles for inclusion.

DATA SYNTHESIS

Six randomized controlled trials with sufficient data were identified and critically appraised. Three clonidine trials (two vs placebo and one vs midazolam) and three dexmedetomidine trials (two vs fentanyl, one vs midazolam) were included. Due to study heterogeneity it was not possible to pool studies. A narrative synthesis is provided.

CONCLUSIONS

Reporting of study results using the outcome "time maintained at target sedation score' for clonidine or dexmedetomidine was poor. Only one trial compared clonidine with midazolam using a sedation score outcome. This study was underpowered to demonstrate equivalence to midazolam as a sedative. The adjunctive use of clonidine demonstrated significant decreases in opioid use in neonates but not in older groups. Clonidine dose was inconsistent between studies. Dexmedetomidine demonstrated an opioid-sparing effect in two small trials. Further studies, including dose-finding studies and studies with sedation score-based outcomes, are needed.

Neonatal pain control and neurologic effects of anesthetics and sedatives in preterm infants

Preclinical and clinical studies have demonstrated the adverse consequences of untreated pain and stress on brain development in the preterm infant. Sucrose has widely been implemented as standard therapy for minor procedural pain. Anesthetics are commonly utilized in preterm infants during major surgery. Pharmacologic agents (benzodiazepines and opioids) have been examined in clinical trials of preterm infants requiring invasive mechanical ventilation. Controversy exists regarding the safety and long-term impact of these interventions. Ongoing multidisciplinary research will help define the impact of these agents and identify potential alternative therapies.

Clinical pharmacology of midazolam in neonates and children: effect of disease-a review

Midazolam is a benzodiazepine with rapid onset of action and short duration of effect. In healthy neonates the half-life (t_1/2) and the clearance (Cl) are 3.3-fold longer and 3.7-fold smaller, respectively, than in adults. The volume of distribution (Vd) is 1.1 L/kg both in neonates and adults. Midazolam is hydroxylated by CYP3A4 and CYP3A5; the activities of these enzymes surge in the liver in the first weeks of life and thus the metabolic rate of midazolam is lower in neonates than in adults. Midazolam acts as a sedative, as an antiepileptic, for those infants who are refractory to standard antiepileptic therapy, and as an anaesthetic. Information of midazolam as an anaesthetic in infants are very little. Midazolam is usually administered intravenously; when minimal sedation is required, intranasal administration of midazolam is employed. Disease affects the pharmacokinetics of midazolam in neonates; multiple organ failure reduces the Cl of midazolam and mechanical ventilation prolongs the t_1/2 of this drug. ECMO therapy increases t_1/2, Cl, and Vd of midazolam several times. The adverse effects of midazolam in neonates are scarce: pain, tenderness, and thrombophlebitis may occur. Respiratory depression and hypotension appear in a limited percentage of infants following intravenous infusion of midazolam. In conclusion, midazolam is a safe and effective drug which is employed as a sedative, as antiepileptic agent, for infants who are refractory to standard antiepileptic therapy, and as an anaesthetic.

A novel maturation function for clearance of the cytochrome P450 3A substrate midazolam from preterm neonates to adults

BACKGROUND AND OBJECTIVE

Major changes in cytochrome P450 (CYP) 3A activity may be expected in the first few months of life with, later, relatively limited changes. In this analysis we studied the maturation of in vivo CYP3A-mediated clearance of midazolam, as model drug, from preterm neonates of 26 weeks gestational age (GA) to adults.

METHODS

Pharmacokinetic data after intravenous administration of midazolam were obtained from six previously reported studies. Subjects were premature neonates (n = 24; GA 26-33.5 weeks, postnatal age (PNA) 3-11 days, and n = 24; GA 26-37 weeks, PNA 0-1 days), 23 children after elective major craniofacial surgery (age 3-23 months), 18 pediatric intensive-care patients (age 2 days-17 years), 18 pediatric oncology patients (age 3-16 years), and 20 healthy male adults (age 20-31 years). Population pharmacokinetic modeling with systematic covariate analysis was performed by use of NONMEM v6.2.

RESULTS

Across the entire lifespan from premature neonates to adults, bodyweight was a significant covariate for midazolam clearance. The effect of bodyweight was best described by use of an allometric equation with an exponent changing with bodyweight in an exponential manner from 0.84 for preterm neonates (0.77 kg) to 0.44 for adults (89 kg), showing that the most rapid maturation occurs during the youngest age range.

CONCLUSIONS

An in-vivo maturation function for midazolam clearance from premature neonates to adults has been developed. This function can be used to derive evidence-based doses for children, and to simulate exposure to midazolam and possibly other CYP3A substrates across the pediatric age range in population pharmacokinetic models or physiologically based pharmacokinetic models.

Bumetanide, an inhibitor of cation-chloride cotransporter isoform 1, inhibits γ-aminobutyric acidergic excitatory actions and enhances sedative actions of midazolam in neonatal rats

BACKGROUND

It has been shown that γ-aminobutyric acid exerts excitatory actions on the immature brain due to the increased expression of Na(+)-K(+)-2Cl(-) cotransporter isoform 1. The authors sought to clarify whether midazolam, a γ-aminobutyric acid-mimetic hypnotic agent, causes neuronal excitation that can be blocked by bumetanide, a selective inhibitor of Na(+)-K(+)-2Cl(-) cotransporter isoform 1. Furthermore, the authors examined whether bumetanide potentiates the sedative effects of midazolam in neonatal rats.

METHODS

The authors measured the effects of midazolam with or without bumetanide on the cytosolic Ca(2+) concentration ([Ca](2+)(i)) in hippocampal slices (n=3 in each condition) from rats at postnatal days 4, 7, and 28 (P4, P7, and P28) using fura-2 microfluorometry. Neuronal activity in the hippocampus and thalamus after intraperitoneal administration of midazolam with or without bumetanide was estimated by immunostaining of phosphorylated cyclic adenosine monophosphate-response element-binding protein (n=12 in each condition). Furthermore, the authors assessed effects of bumetanide on the sedative effect of midazolam by measuring righting reflex latency (n=6 in each condition).

RESULTS

Midazolam significantly increased [Ca](2+)(i) in the CA3 area at P4 and P7 but not at P28. Bumetanide inhibited midazolam-induced increase in [Ca](2+)(i). Midazolam significantly up-regulated phosphorylated cyclic adenosine monophosphate-response element-binding protein expression in a bumetanide-sensitive manner in the hippocampus at P7 but not P28. Bumetanide enhanced the sedative effects of midazolam in P4 and P7 but not P28 rats.

CONCLUSION

These results suggest that γ-aminobutyric acid A receptor-mediated excitation plays an important role in attenuated sedative effects of midazolam in immature rats.

Therapeutic interventions and short-term outcomes for infants with severe bronchopulmonary dysplasia born at <32 weeks' gestation

OBJECTIVE

To characterize the treatments and short-term outcomes in infants with severe bronchopulmonary dysplasia (sBPD) referred to regional neonatal intensive care units.

STUDY DESIGN

Infants born <32 weeks' gestation with sBPD were identified using the Children's Hospital Neonatal Database. Descriptive outcomes are reported.

RESULT

A total of 867 patients were eligible. On average, infants were born at 26 weeks' gestation and referred 43 days after birth. Infants frequently experienced lung injury (pneumonia: 24.1%; air leak: 9%) and received systemic corticosteroids (61%) and mechanical ventilation (median duration 37 days). Although 91% survived to discharge, the mean post-menstrual age was 47 weeks. Ongoing care such as supplemental oxygen (66%) and tracheostomy (5%) were frequently needed.

CONCLUSION

Referred infants with sBPD sustain multiple insults to lung function and development. Because affected infants have no proven, safe or efficacious therapy and endure an exceptional burden of care even after referral, urgent work is required to observe and improve their outcomes.

Sedation and analgesia to facilitate mechanical ventilation

Regardless of age, health care professionals have a professional and ethical obligation to provide safe and effective analgesia to patients undergoing painful procedures. Historically, newborns, particularly premature and sick infants, have been undertreated for pain. Intubation of the trachea and mechanical ventilation are ubiquitous painful procedures in the neonatal intensive care unit that are poorly assessed and treated. The authors review the use of sedation and analgesia to facilitate endotracheal tube placement and mechanical ventilation. Controversies regarding possible adverse neurodevelopmental outcomes after sedative and anesthetic exposure and in the failure to treat pain is also discussed.

Premedication for neonatal intubation: Current practice in Saudi Arabia

BACKGROUND

Despite strong evidence of the benefits of rapid sequence intubation in neonates, it is still infrequently utilized in neonatal intensive care units (NICU), contributing to avoidable pain and secondary procedure-related physiological disturbances.

OBJECTIVES

The primary objective of this cross-sectional survey was to assess the practice of premedication and regimens commonly used before elective endotracheal intubation in NICUs in Saudi Arabia. The secondary aim was to explore neonatal physicians' attitudes regarding this intervention in institutions across Saudi Arabia.

METHODS

A web-based, structured questionnaire was distributed by the Department of Pediatrics, Umm Al Qura University, Mecca, to neonatal physicians and consultants of 10 NICUs across the country by E-mail. Responses were tabulated and descriptive statistics were conducted on the variables extracted.

RESULTS

85% responded to the survey. Although 70% believed it was essential to routinely use premedication for all elective intubations, only 41% implemented this strategy. 60% cited fear of potential side effects for avoiding premedication and 40% indicated that the procedure could be executed more rapidly without drug therapy. Treatment regimens varied widely among respondents.

CONCLUSION

Rates of premedication use prior to non-emergent neonatal intubation are suboptimal. Flawed information and lack of unified unit policies hampered effective implementation. Evidence-based guidelines may influence country-wide adoption of this practice.

The role of systematic reviews in pharmacovigilance planning and Clinical Trials Authorisation application: example from the SLEEPS trial

BACKGROUND

Adequate sedation is crucial to the management of children requiring assisted ventilation on Paediatric Intensive Care Units (PICU). The evidence-base of randomised controlled trials (RCTs) in this area is small and a trial was planned to compare midazolam and clonidine, two sedatives widely used within PICUs neither of which being licensed for that use. The application to obtain a Clinical Trials Authorisation from the Medicines and Healthcare products Regulatory Agency (MHRA) required a dossier summarising the safety profiles of each drug and the pharmacovigilance plan for the trial needed to be determined by this information. A systematic review was undertaken to identify reports relating to the safety of each drug.

METHODOLOGY/PRINCIPAL FINDINGS

The Summary of Product Characteristics (SmPC) were obtained for each sedative. The MHRA were requested to provide reports relating to the use of each drug as a sedative in children under the age of 16. Medline was searched to identify RCTs, controlled clinical trials, observational studies, case reports and series. 288 abstracts were identified for midazolam and 16 for clonidine with full texts obtained for 80 and 6 articles respectively. Thirty-three studies provided data for midazolam and two for clonidine. The majority of data has come from observational studies and case reports. The MHRA provided details of 10 and 3 reports of suspected adverse drug reactions.

CONCLUSIONS/SIGNIFICANCE

No adverse reactions were identified in addition to those specified within the SmPC for the licensed use of the drugs. Based on this information and the wide spread use of both sedatives in routine practice the pharmacovigilance plan was restricted to adverse reactions. The Clinical Trials Authorisation was granted based on the data presented in the SmPC and the pharmacovigilance plan within the clinical trial protocol restricting collection and reporting to adverse reactions.

Sedation and analgesia in mechanically ventilated preterm neonates: continue standard of care or experiment?

Attention to comfort and pain control are essential components of neonatal intensive care. Preterm neonates are uniquely susceptible to pain and agitation, and these exposures have a negative impact on brain development. In preterm neonates, chronic pain and agitation are common adverse effects of mechanical ventilation, and opiates or benzodiazepines are the pharmacologic agents most often used for treatment. Questions remain regarding the efficacy, safety, and neurodevelopmental impact of these therapies. Both preclinical and clinical data suggest troubling adverse drug reactions and the potential for adverse longterm neurodevelopmental impact. The negative impacts of standard pharmacologic agents suggest that alternative agents should be investigated. Dexmedetomidine is a promising alternative therapy that requires further interprofessional and multidisciplinary research in this population.

Premedication for endotracheal intubation in the newborn infant

Endotracheal intubation, a common procedure in newborn care, is associated with pain and cardiorespiratory instability. The use of premedication reduces the adverse physiological responses of bradycardia, systemic hypertension, intracranial hypertension and hypoxia. Perhaps more importantly, premedication decreases the pain and discomfort associated with the procedure. All newborn infants, therefore, should receive analgesic premedication for endotracheal intubation except in emergency situations. Based on current evidence, an optimal protocol for premedication is to administer a vagolytic (intravenous [IV] atropine 20 μg/kg), a rapid-acting analgesic (IV fentanyl 3 μg/kg to 5 μg/kg; slow infusion) and a short-duration muscle relaxant (IV succinylcholine 2 mg/kg). Intubations should be performed or supervised by trained staff, with close monitoring of the infant throughout.

Intravenous midazolam infusion for sedation of infants in the neonatal intensive care unit

BACKGROUND

Proper sedation for neonates undergoing uncomfortable procedures may reduce stress and avoid complications. Midazolam is a short-acting benzodiazepine that is increasingly used in neonatal intensive care units (NICU). However, its effectiveness as a sedative in neonates has not been systematically evaluated.

OBJECTIVES

To determine whether intravenous midazolam infusion is an effective sedative, as evaluated by behavioural or physiological measurements, or both, for critically ill neonates undergoing intensive care and to assess clinically significant short- and long-term adverse effects associated with its use.

SEARCH METHODS

We performed a literature search according to the Cochrane Neonatal Review Group search strategy. Randomised and quasi-randomised controlled trials of intravenous midazolam use in neonates were identified by searching the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 3, 2012), MEDLINE (1985 to 2012), EMBASE (1980 to 2012), CINAHL (1981 to 2012), reference lists of published studies, personal files, and abstracts published in The Pediatric Academic Societies Meeting Abstract Archives from 1990 to 2011.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials of intravenous midazolam infusion in infants aged 28 days or less for sedation were selected for review.

DATA COLLECTION AND ANALYSIS

Data regarding the primary outcome of level of sedation were abstracted. Secondary outcomes such as intraventricular haemorrhage (IVH), periventricular leukomalacia (PVL), death, length of NICU stay, and adverse effects associated with midazolam were assessed. When appropriate, meta-analyses were performed using risk ratio (RR), risk difference (RD), along with their 95% confidence intervals (95% CI) for categorical variables and weighted mean difference (WMD) for continuous variables.

MAIN RESULTS

Three trials were included in the review. Using different sedation scales, each study showed a statistically significantly higher sedation level in the midazolam group compared to the placebo group. However, since none of the sedation scales used have been validated in preterm infants, the effectiveness of midazolam in this population could not be ascertained. One study showed a statistically significant higher incidence of adverse neurological events (death, grade III or IV IVH, PVL), and meta-analysis of data from two studies showed a statistically significant longer duration of NICU stay in the midazolam group compared to the placebo group.

AUTHORS' CONCLUSIONS

There are insufficient data to promote the use of intravenous midazolam infusion as a sedative for neonates undergoing intensive care. This review raises concerns about the safety of midazolam in neonates. Further research on the effectiveness and safety of midazolam in neonates is needed.

Profound changes in drug metabolism enzymes and possible effects on drug therapy in neonates and children

INTRODUCTION

There are profound changes that take place in drug metabolism enzymes during fetal and postnatal development. These changes may significantly impact drug therapy in children.

AREAS COVERED

A combination of focused and comprehensive literature searches using PubMed and reference lists (from inception to 7 November 2009) is undertaken to identify reports on in vitro and in vivo development of drug metabolism enzymes as well disposition of selected drugs and their effect in children. The article provides an update on development of drug metabolism enzymes and their impact on drug substrate disposition and disease, which may aid to improve clinical practice and optimally design clinical trials in children.

EXPERT OPINION

Drug metabolism enzyme activity changes profoundly throughout the continuum of postnatal development and often results in different disposition pathways than in adults. Genetics and co-morbidity interact significantly with these developmental changes. Translation of existing knowledge into age-adjusted dosing guidelines and clinical trial design is highly needed for there to be an improvement in drug therapy in children.

Haemodynamics of intravenous paracetamol in neonates

INTRODUCTION

Reports on the haemodynamics of intravenous (iv) paracetamol in adult intensive care were recently published. We therefore wanted to explore the haemodynamics of iv paracetamol in neonates.

METHODS

Retrospective, pooled analysis of heart rate (bpm) and blood pressure (mean, systolic, diastolic) observations collected during iv paracetamol pharmacokinetic studies in neonates. Heart rate and blood pressure were recorded just before and 30, 60, 120, 180, 240, 300 and 360 min after iv paracetamol (paired, ANOVA). Clinical characteristics in hypotensive (mean mmHg < gestational age, weeks) cases were compared with controls (Mann-Whitney U test).

RESULTS

Based on observations in 72 neonates, heart rate decreased from 145 (SD 20) to 138 (21), 141 (20), 137 (20), 137 (22), 140 (20), 139 (20) and 140 (21) bpm (paired p < 0.05, ANOVA p = 0.36). There were no changes in systolic and diastolic pressure, but mean arterial pressure decreased from 46 (7) to 43 (8) mmHg at 60 min (paired p < 0.05, ANOVA p = 0.75). Eight neonates developed hypotension. These patients had lower pre-administration arterial pressure (38 vs 47 mmHg, p < 0.05).

CONCLUSIONS

In a setting of open label administration to alleviate (procedural) pain, haemodynamic effects of iv paracetamol in neonates remained modest. We suggest considering impaired haemodynamics to be a relative contra-indication for iv paracetamol in neonates.

Premedication for nonemergency endotracheal intubation in the neonate

Endotracheal intubation is a common procedure in newborn care. The purpose of this clinical report is to review currently available evidence on use of premedication for intubation, identify gaps in knowledge, and provide guidance for making decisions about the use of premedication.

Use of analgesic and sedative drugs in the NICU: integrating clinical trials and laboratory data

Recent advances in neonatal intensive care include and are partly attributable to growing attention for comfort and pain control in the term and preterm infant requiring intensive care.Limitation of painful procedures is certainly possible, but most critically ill infants require unavoidable painful or stressful procedures such as intubation, mechanical ventilation, or catheterization.Many analgesics (opioids and nonsteroidal anti-inflammatory drugs)and sedatives (benzodiazepines and other anesthetic agents) are available but their use varies considerably among units. This review summarizes current experimental knowledge on the effects of sedative and analgesic drugs on brain development and reviews clinical evidence that speaks for or against the use of common analgesic and sedative drugs in the NICU but avoids any discussion of anesthesia during surgery. Risk/benefit ratios of intermittent boluses or continuous infusions for the commonly used sedative and analgesic agents are discussed in the light of clinical and experimental studies. The limitations of extrapolating experimental results from animals to humans must be considered while making practical recommendations based on the currently available evidence.

Use of premedication for intubation in tertiary neonatal units in the United Kingdom

BACKGROUND

Endotracheal intubation and laryngoscopy are frequently performed procedures in neonatal intensive care. These procedures represent profoundly painful stimuli and have been associated with laryngospasm, bronchospasm, hemodynamic changes, raised intracranial pressure and an increased risk of intracranial hemorrhage. These adverse changes can cause significant neonatal morbidity but may be attenuated by the use of suitable premedication.

AIMS

To evaluate current practices for premedication use prior to elective intubation in UK tertiary neonatal units.

METHODS

Telephone questionnaire survey of all 50 tertiary neonatal units in the UK.

RESULTS

Ninety percent of units report the routine use of sedation prior to intubation and 82% of units routinely use a muscle relaxant. Morphine was the most commonly used sedative and suxamethonium was the most commonly used muscle relaxant. Approximately half of the units also used atropine during intubation. Seventy seven percent of units had a written policy for premedication. Ten percent of the units did not routinely use any sedatives or muscle relaxants for elective intubation.

CONCLUSIONS

In comparison with data from a 1998 survey, our study demonstrated an increase in the number of units that have adopted a written policy for premedication use, and in the number routinely using premedication drugs for elective intubation. There remains little consensus as to which drugs should be used and in what dose.

Do ventilated neonates require pain management?

Mechanical ventilation is a stressful experience in neonates resulting in changes in neuroendocrine parameters, pain scores, and physiologic responses. Assisted ventilation in neonates is presumed to be associated with chronic repetitive pain, which in turn is associated with adverse long-term sequelae. Reasons to routinely sedate ventilated neonates include improved ventilator synchrony, improved pulmonary function, and decreased neuroendocrine responses, including cortisol, beta-endorphine, and catecholamines. Reasons not to treat include the well-known adverse side effects of pain medication, especially the opiates, including hypotension from morphine, chest wall rigidity from fentanyl, and tolerance, dependence, and withdrawal from both opiates and benzodiazepines. Additionally, adverse effects such as death and IVH are not improved with preemptive treatment. Chronic pain assessment is poorly validated and difficult to assess in this population, and most studies have evaluated only acute pain scores. If patients are treated, opiates are the most common class of drugs, with morphine the most well studied. Fentanyl may be advantageous in hypotensive, younger neonates because it has fewer cardiovascular effects. The benzodiazepines, midazolam and lorazepam, have been used in ventilated neonates, but midazolam has been associated with adverse effects in one small study so concern remains regarding its use. Significant gaps in our knowledge exist, especially in regard to long-term effects of treatment, or lack thereof, and in the assessment of the chronic pain associated with assisted ventilation.

Pharmacogenetics and paediatric drug development: issues and consequences to labelling and dosing recommendations

The area of pharmacogenetics (PGt) is evolving rapidly. However, ongoing efforts in this field are not aligned with the requirements for the inclusion of clinically relevant findings into the label, especially with reference to paediatric indications. Clinical research in children poses unique issues from a practical and technical perspective, but many challenges can be overcome by applying advanced study design and data analysis methods. When investigating the role of PGt factors on treatment effect, all features that influence drug response must be taken into account. Yet, PGt often has a privileged status in research protocols, with PGt factors evaluated independently from other determinants of response, instead of being regarded as other demographic or clinical covariates (e.g., age, renal function). At present, guidelines to incorporate PGt findings into label statements are lacking in part because this is a new and incompletely understood area. This situation is no longer acceptable. To achieve the potential that PGt can offer to drug development and ultimately to drug prescription, academia, industry and regulatory agencies need to pool resources on the revision of study design and data analysis requisites, bringing in model-based methodologies to enable accurate interpretation of results and provide appropriate labelling recommendations.

Pharmacological therapy for analgesia and sedation in the newborn

Rapid advances have been made in the use of pharmacological analgesia and sedation for newborns requiring neonatal intensive care. Practical considerations for the use of systemic analgesics (opioids, non-steroidal anti-inflammatory agents, other drugs), local and topical anaesthetics, and sedative or anaesthetic agents (benzodiazepines, barbiturates, other drugs) are summarised using an evidence-based medicine approach, while avoiding mention of the underlying basic physiology or pharmacology. These developments have inspired more humane approaches to neonatal intensive care. Despite these advances, little is known about the clinical effectiveness, immediate toxicity, effects on special patient populations, or long-term effects after neonatal exposure to analgesics or sedatives. The desired or adverse effects of drug combinations, interactions with non-pharmacological interventions or use for specific conditions also remain unknown. Despite the huge gaps in our knowledge, preliminary evidence for the use of neonatal analgesia and sedation is available, but must be combined with a clear definition of clinical goals, continuous physiological monitoring, evaluation of side effects or tolerance, and consideration of long-term clinical outcomes.

Effects of Midazolam and Morphine on Cerebral Oxygenation and Hemodynamics in Ventilated Premature Infants

BACKGROUND

Midazolam sedation and morphine analgesia are commonly used in ventilated premature infants.

OBJECTIVES

To evaluate the effects of midazolam versus morphine infusion on cerebral oxygenation and hemodynamics in ventilated premature infants.

METHODS

11 patients (GA 26.6-33.0 weeks, BW 780-2,335 g) were sedated with midazolam (loading dose 0.2 mg/kg, maintenance 0.2 mg/kg/h) and 10 patients (GA 26.4-33.3 weeks, BW 842-1,955 g) were sedated with morphine (loading dose 0.05 mg/kg, maintenance 0.01 mg/kg/h). Changes in oxyhemoglobin (Delta cO2Hb) and deoxyhemoglobin (Delta cHHb) were assessed using near infrared spectrophotometry. Changes in cHbD (= Delta cO(2)Hb - Delta cHHb) reflect changes in cerebral blood oxygenation and changes in concentration of total hemoglobin (Delta ctHb = Delta cO2Hb + Delta cHHb) represent changes in cerebral blood volume (DeltaCBV). Changes in cerebral blood flow velocity (DeltaCBFV) were intermittently measured using Doppler ultrasound. Heart rate (HR), mean arterial blood pressure (MABP), arterial oxygen saturation (saO2) and transcutaneous measured pO2 (tcpO2) and pCO2 (tcpCO2) were continuously registered. Statistical analyses were carried out using linear mixed models to account for the longitudinal character study design.

RESULTS

Within 15 min after the loading dose of midazolam, a decrease in saO2, tcpO2 and cHbD was observed in 5/11 infants. In addition, a fall in MABP and CBFV was observed 15 min after midazolam administration. Immediately after morphine infusion a decrease in saO2, tcpO2 and cHbD was observed in 6/10 infants. Furthermore, morphine infusion resulted in a persistent increase in CBV.

CONCLUSIONS

Administration of midazolam and morphine in ventilated premature infants causes significant changes in cerebral oxygenation and hemodynamics, which might be harmful.

Analgesia and local anesthesia during invasive procedures in the neonate

BACKGROUND

Preterm and full-term neonates admitted to the neonatal intensive care unit or elsewhere in the hospital are routinely subjected to invasive procedures that can cause acute pain. Despite published data on the complex behavioral, physiologic, and biochemical responses of these neonates and the detrimental short- and long-term clinical outcomes of exposure to repetitive pain, clinical use of pain-control measures in neonates undergoing invasive procedures remains sporadic and suboptimal. As part of the Newborn Drug Development Initiative, the US Food and Drug Administration and the National Institute of Child Health and Human Development invited a group of international experts to form the Neonatal Pain Control Group to review the therapeutic options for pain management associated with the most commonly performed invasive procedures in neonates and to identify research priorities in this area.

OBJECTIVE

The goal of this article was to review and synthesize the published clinical evidence for the management of pain caused by invasive procedures in preterm and full-term neonates.

METHODS

Clinical studies examining various therapies for procedural pain in neonates were identified by searches of MEDLINE (1980-2004), the Cochrane Controlled Trials Register (The Cochrane Library, Issue 1, 2004), the reference lists of review articles, and personal files. The search terms included specific drug names, infant-newborn, infant-preterm, and pain, using the explode function for each key word. The English-language literature was reviewed, and case reports and small case series were discarded.

RESULTS

The most commonly performed invasive procedures in neonates included heel lancing, venipuncture, IV or arterial cannulation, chest tube placement, tracheal intubation or suctioning, lumbar puncture, circumcision, and SC or IM injection. Various drug classes were examined critically, including opioid analgesics, sedative/hypnotic drugs, nonsteroidal anti-inflammatory drugs and acetaminophen, injectable and topical local anesthetics, and sucrose. Research considerations related to each drug category were identified, potential obstacles to the systematic study of these drugs were discussed, and current gaps in knowledge were enumerated to define future research needs. Discussions relating to the optimal design for and ethical constraints on the study of neonatal pain will be published separately. Well-designed clinical trials investigating currently available and new therapies for acute pain in neonates will provide the scientific framework for effective pain management in neonates undergoing invasive procedures.

Analgesia and sedation during mechanical ventilation in neonates

BACKGROUND

Endotracheal intubation and mechanical ventilation are major components of routine intensive care for very low birth weight newborns and sick full-term newborns. These procedures are associated with physiologic, biochemical, and clinical responses indicating pain and stress in the newborn. Most neonates receive some form of analgesia and sedation during mechanical ventilation, although there are marked variations in clinical practice. Clinical guidelines for pharmacologic analgesia and sedation in newborns based on robust scientific data are lacking, as are measures of clinical efficacy.

OBJECTIVE

This article represents a preliminary attempt to develop a scientific rationale for analgesia sedation in mechanically ventilated newborns based on a systematic analysis of published clinical trials.

METHODS

The current literature was reviewed with regard to the use of opioids (fentanyl, morphine, diamorphine), sedative-hypnotics (midazolam), nonsteroidal anti-inflammatory drugs (ibuprofen, indomethacin), and acetaminophen in ventilated neonates. Original meta-analyses were conducted that collated the data from randomized clinical comparisons of morphine or fentanyl with placebo, or morphine with fentanyl.

RESULTS

The results of randomized trials comparing fentanyl, morphine, or midazolam with placebo, and fentanyl with morphine were inconclusive because of small sample sizes. Meta-analyses of the randomized controlled trials indicated that morphine and fentanyl can reduce behavioral and physiologic measures of pain and stress in mechanically ventilated preterm neonates but may prolong the duration of ventilation or produce other adverse effects. Randomized trials of midazolam compared with placebo reported significant adverse effects (P < 0.05) and no apparent clinical benefit; the findings of a meta-analysis suggest that there are insufficient data to justify use of IV midazolam for sedation in ventilated neonates.

CONCLUSIONS

Despite ongoing research in this area, huge gaps in our knowledge remain. Well-designed and adequately powered clinical trials are needed to establish the safety, efficacy, and short- and long-term outcomes of analgesia and sedation in the mechanically ventilated newborn.

Remifentanil for sedation and analgesia in a preterm neonate with respiratory distress syndrome

We present the efficacy and safety of the use of remifentanil for intubation, sedation and analgesia in a preterm infant during mechanical ventilation for respiratory distress syndrome. A 34-week-old baby, born by cesarean delivery that developed respiratory distress, required intubation and ventilatory support. For intubation, the baby was given midazolam (0.2 mg.kg(-1)) and remifentanil (1 microg.kg(-1)). The intubation conditions were assessed and classified as excellent. The remifentanil infusion was started at dose 0.75 microg.kg(-1).min(-1) and the dose adjustments were made depending on the neonatal infant pain scale (NIPS), hemodynamic and respiratory changes or the presence of spontaneous movements. Pulse oximetry, respiratory rate, ECG and invasive blood pressure were continuously monitored. He was given surfactant within 2.5 h of life after which ventilator parameters could be progressively decreased. Three hours later, the remifentanil infusion was decreased to 0.5 microg.kg(-1).min(-1), and he remained sedated (NIPS < 2). Six hour after surfactant administration, blood gases and chest X ray were normal. The remifentanil infusion was then discontinued and 30 min later the baby was awake and extubated with success. There were no side effects after intubation or during the continuous infusion. The profile of remifentanil allowing a rapid recovery, the absence of side effects and a good level of sedation and analgesia support the choice of this opioid for sedation in the NICU.

Minimum effective dose of midazolam for sedation of mechanically ventilated neonates

OBJECTIVE

To determine the minimal effective dose (MED) of intravenous midazolam, required for appropriate sedation in 95% of patients, 1 h after drug administration.

METHODS

A double-blind dose-finding study using the continual reassessment method, a Bayesian sequential design. Twenty-three newborn infants hospitalized in intensive care unit participated. Inclusion criteria were: (i) post-natal age <28 days, (ii) gestational age >33 weeks, (iii) intubation and ventilatory support required for respiratory distress syndrome, (iv) need for sedation (i.e. one of the six following criteria: agitation or grimacing or crying facial expression before tracheal suctioning, agitation or grimacing or crying facial expression during tracheal suctioning). Each neonate was allocated to a loading dose, ranging from 75 to 200 microg/kg, and a maintenance dose ranging from 37.5 to 100 microg/kg/h.

RESULTS

The primary endpoint was the level of sedation 1 h after the onset of infusion. The sedation procedure was classified as a success if all the following clinical criteria were met: no agitation, no grimacing and no crying facial expression before as well as during tracheal suctioning. Based on the 23 patients, the final estimated probability of success was 76.9% (95% credibility interval: 56.6-91.4%) for the 200 microg/kg loading dose. no significant adverse effect was observed.

CONCLUSIONS

Continual reassessment is a new approach, suitable for dose-finding study in neonates. this method overcomes some of the ethical, statistical and practical problems associated with this population. Using this method, the MED was estimated to be the 200 mug/kg loading dose of midazolam.

Morphine administration and short-term pulmonary outcomes among ventilated preterm infants

BACKGROUND

The use of opioid therapy for sedation and analgesia among ventilated infants varies among care providers. The impact of opioid therapy early in the neonatal course of respiratory distress syndrome (RDS) on pulmonary outcomes is not known.

OBJECTIVE

We tested the hypothesis that preterm neonates randomized to the morphine infusion group would have improved ventilatory outcomes, measured as shorter durations of ventilator or oxygen therapy, fewer air leaks, and lower incidence of bronchopulmonary dysplasia.

METHODS

All 898 subjects (gestational age [GA] of > or =23 to < or =32 weeks) who were enrolled in the Neurologic Outcomes and Preemptive Analgesia in Neonates (NEOPAIN) trial formed the study cohort (morphine: 449 patients; placebo: 449 patients). Subjects received the masked study drug until they were weaned from the ventilator or for 14 days, whichever occurred earlier. Outcome measures included air leaks, duration of ventilation or oxygen therapy, hospitalization, bronchopulmonary dysplasia, and death.

RESULTS

Subjects in the 2 groups had similar baseline characteristics (mean +/- SD, morphine versus placebo: GA: 27.3 +/- 2.3 vs 27.4 +/- 2.3 weeks; birth weight: 1037 +/- 340 vs 1054 +/- 354 g). Infants in the morphine group required ventilator therapy significantly longer, compared with the placebo group (median [interquartile range]: 7 days [4-20 days] vs 6 days [3-19 days]). This difference in ventilation duration was significant for infants with GA of 27 to 29 weeks (6 days [4-12 days] vs 5 days [2-9 days]) and 30 to 32 weeks (4 days [3-6 days] vs 3 days [2-5 days]). Infants who received additional analgesia with intermittent morphine doses in both groups were sicker than those who were not given open-label morphine. After adjustment for birth weight, Clinical Risk Index for Babies scores, maternal chorioamnionitis, RDS requiring surfactant, and patent ductus arteriosus in a logistic regression model, the use of additional analgesia with morphine was associated independently with increased air leaks and longer durations of high-frequency ventilation, nasal continuous positive airway pressure, and oxygen therapy.

CONCLUSIONS

Morphine infusions do not improve short-term pulmonary outcomes among ventilated preterm neonates. Additional morphine doses were associated with worsening respiratory outcomes among preterm neonates with RDS.

Sedation and analgesia in the pediatric intensive care unit

Various clinical situations may arise in the PICU that necessitate the use of sedation, analgesia, or both. Although there is a large clinical experience with midazolam in the PICU population and it remains the most commonly used benzodiazepine in this setting, lorazepam may provide an effective alternative, with a longer half-life and more predictable pharmacokinetics without the concern of active metabolites. However, there are limited reports regarding its use in the PICU population, and concerns exist regarding the potential for toxicity related to its diluent, propylene glycol. Although the synthetic opioid fentanyl frequently is chosen for use in the PICU setting because of its hemodynamic stability, preliminary data suggest morphine may have a slower development of tolerance and may cause fewer withdrawal symptoms than fentanyl. Morphine's safety profile includes long-term follow-up studies that have demonstrated no adverse central nervous system developmental effects from its use in neonates and infants. In the critically ill infant at risk following surgery for congenital heart disease, clinical experience supports the use of the synthetic opioids, given their ability to modulate PVR and prevent pulmonary hypertensive crisis. Alternatives to the benzodiazepines and opioids include ketamine, pentobarbital, or dexmedetomidine. Ketamine may be useful for patients with hemodynamic instability or airway reactivity. There are limited reports regarding the use of pentobarbital in the PICU, with one study raising concerns of a high incidence of adverse effects associated with its use. Propofol has gained great favor in the adult population as a means of providing deep sedation while allowing for rapid awakening; however, its routine use is not recommended because of its potential association with "propofol infusion syndrome." As the pediatric experience increases, it appears that there will be a role for newer agents such as dexmedetomidine.

Premedication for tracheal intubation: A prospective survey in 75 neonatal and pediatric intensive care units*

OBJECTIVE

In children, like in adults, tracheal intubation is a painful procedure that may induce hypertension, tachycardia, and other undesirable hemodynamic disorders. Although premature neonates are very sensitive to pain and vulnerable to its long-term effects, the need for sedation before tracheal intubation is still discussed in neonatal units. Our objective was to investigate the practice of premedication before tracheal intubation in neonatal and pediatric units and determine the influence of premedication on intubating conditions.

DESIGN

We performed a 10-day prospective survey in 75 neonatal and pediatric intensive care units among the 98 licensed in France. A questionnaire was completed for each intubation performed in each surveyed unit.

SUBJECTS

A total of 204 patients were studied: 140 neonates, 52 infants, and 12 children.

MAIN RESULTS

Data on 204 tracheal intubations were collected from 223 that were performed during the study period (participation rate, 91.4%). Premedication was used before intubation for 37.1%, 67.3%, and 91.7% of neonates, infants, and children, respectively (p <.0001). In the subgroup of neonates, premedication was particularly rare for the youngest and the smallest infants. Midazolam was the principle hypnotic used in neonates, whereas propofol was mainly used in children. Opioids or muscle relaxants were used in 16.2% and 4.4% of the patients, respectively. A low success rate and a high incidence of hypoxemia and bradycardia were correlated with the inexperience of the operator. Premedication did not significantly influence either the success rate or the undesirable events associated with tracheal intubation.

CONCLUSION

Use of premedication before tracheal intubation is limited in neonates and increases according to the age of the patient. Midazolam does not seem to be an accurate choice to improve intubating conditions in neonates and infants. Because tracheal intubation is a technique that requires a skill only developed by regular practice, operators who have limited experience with intubating children should be supported by senior operators.

Impact of Solutol HS 15 on the pharmacokinetic behavior of midazolam upon intravenous administration to male Wistar rats

The pharmacokinetic profile of midazolam (MDZ) and its major metabolites 1'-OH-midazolam (1'OH-MDZ) and 4-OH-midazolam (4OH-MDZ) was investigated in rats. MDZ was administered intravenously at 5 mg/kg either in the absence (NaCl 0.9%, control group) or in the presence of the surfactant Solutol HS 15, a weak inhibitor of cytochrome P450 3A (CYP3A) activity in vitro (Solutol HS 15-treated group). It was found that the pharmacokinetic profiles of MDZ, 1'OH-MDZ and 4OH MDZ did not differ significantly in the two dosing vehicles (P values above 0.2). MDZ exhibited a high plasma clearance (Cl) of 79 and 92 ml/min/kg (corresponding to a blood Cl of 64 and 75 ml/min/kg), a high volume of distribution (V(d)) of 4.0 and 3.6 l/kg, and an area under the plasma concentration-time curve (AUC(t0-tinf)) of 1062 and 932 h.ng/ml in the control group and in the Solutol HS 15-treated group, respectively. The amount of MDZ excreted unchanged into urine was below 0.01% with both dosing vehicles. AUC(t0-tinf) in the control group was 12.3 h.ng/ml for 1'OH-MDZ and 38.8 h.ng/ml 4OH-MDZ. In the Solutol HS 15-treated group, AUC(t0-tinf) was 14 h.ng/ml for 1'OH-MDZ and 35.4 h.ng/ml for 4OH-MDZ. The metabolite concentrations excreted into urine were below the limit of quantification. In the rat, MDZ has a high blood clearance that is limited by liver blood flow. Therefore, weak CYP3A inhibitors like Solutol HS 15 are not likely to affect the hepatic blood clearance of MDZ in vivo.

Intravenous midazolam infusion for sedation of infants in the neonatal intensive care unit

BACKGROUND

The need for sedation for neonates undergoing uncomfortable procedures in the neonatal intensive care unit (NICU) has often been overlooked. Proper sedation may reduce stress and avoid complications during procedures such as mechanical ventilation. Midazolam is a short acting benzodiazepine that has been increasingly used in the NICU. However, the effectiveness of intravenous midazolam as a sedative in neonates has not been systematically evaluated.

OBJECTIVES

To determine whether intravenous midazolam infusion is an effective sedative, as evaluated by behavioural and/or physiologic measurements, for critically ill neonates undergoing intensive care, and to assess clinically significant short and long term adverse effects associated with its use.

SEARCH STRATEGY

Literature search according to the Cochrane Neonatal Review Group search strategy. Randomized and quasi-randomized controlled trials of intravenous midazolam use in neonates were identified by searching the Cochrane Controlled Trials Register (The Cochrane Library, Issue 3, 2002), MEDLINE (1985-2002), EMBASE (1980-2002), reference lists of published studies, personal files, and abstracts published in Pediatric Research from 1990-2002.

SELECTION CRITERIA

Randomized and quasi-randomized controlled trials of intravenous midazolam infusion in infants </= 28 days of age for sedation during mechanical ventilation or radiologic investigations were selected for review. Studies on midazolam use as an anesthetic or an anticonvulsant were excluded. Studies involving neonates and older infants and children were excluded if data for neonates could not be extracted.

DATA COLLECTION AND ANALYSIS

Data regarding the primary outcome of level of sedation (as evaluated by behavioural scales or physiologic parameters) were abstracted. Secondary outcomes including intraventricular hemorrhage (IVH), periventricular leukomalacia (PVL), death within 28 days of age, adverse effects associated with midazolam (hemodynamic and neurologic), days of ventilation, days of supplemental oxygen use, pneumothorax, length of NICU stay, and long term neurodevelopmental outcome were assessed. When appropriate, meta-analyses were performed using relative risk (RR), risk difference (RD), along with their 95% confidence intervals (95% CI) for categorical variables and weighted mean difference (WMD) for continuous variables.

MAIN RESULTS

Three trials were eligible for inclusion in the review. Data on level of sedation from the three trials could not be combined for meta-analysis because of differences in tools used to measure sedation levels. Two studies (Jacqz-Aigrain 1994, Arya 2001) showed a statistically significantly higher level of sedation in the midazolam group compared to the placebo group. The third study (Anand 1999) comparing midazolam to morphine and placebo found no statistically significant difference in sedation level among the three groups, but a statistically significantly higher level of sedation was found in the midazolam group compared with the placebo group during the treatment infusion. However, since the sedation scales used in all three studies have not been validated in preterm infants, the effectiveness of midazolam as a sedative in this population could not be ascertained. In the study by Jacqz-Aigrain et al (Jacqz-Aigrain 1994), blood pressure was statistically significantly lower in the midazolam group than in the placebo group on days one and two, although there was no statistically significant difference in the incidence of hypotension requiring albumin or vasoactive drugs between groups. The study by Anand et al (Anand 1999) showed a statistically significant higher incidence of adverse neurologic events (death, grade III-IV IVH, PVL) in the midazolam group compared with the other groups. In addition, meta-analysis of available data from two studies (Jacqz-Aigrain 1994, Anand 1999) showed a statistically significantly longer duration of NICU stay in the midazolam group compared to the placebo group (WMD 5.4 days, 95%CI 0.4, 10.5). Meta-analyses of other secondary outcomes showed no statistically significant differences between the midazolam and placebo groups.

REVIEWER'S CONCLUSIONS

There are insufficient data to promote the use of intravenous midazolam infusion as a sedative for neonates undergoing intensive care. This review raises concerns about the safety of midazolam in neonates. Further research on the effectiveness and safety of midazolam in neonates is needed.

Plasma concentrations of midazolam in neonates receiving extracorporeal membrane oxygenation

Drug disposition is affected during extracorporeal membrane oxygenation (ECMO). This study investigates the dose-concentration relationship of midazolam in neonates requiring ECMO during continuous infusion into the circuit (extracorporeally; n = 10) and intravenously (n = 10). Data on hourly doses and sedation scores were collected for 120 hours. Plasma concentrations were analyzed at times 0, 2, 4, 6, 12, 18, and 24, and every 12 hours thereafter. Both groups were clinically similar. Mean (standard deviation) dose for all patients was 250 (185) microg/kg/h, four times greater than previously reported. Doses administered in the first 24 hours were significantly greater extracorporeally [361 (300)] compared with intravenous [258 (190) microg/kg/h, p < 0.001]. Mean (standard deviation) plasma concentrations in all patients at 24, 48, and 72 hours were 1.4 (0.9), 1.8 (1.2), and 2.6 (1.8) microg/ml, respectively. Satisfactory sedation levels were achieved in all patients. Comparison of the actual observed with predicted (simulated) midazolam concentrations suggested significant attenuation of plasma levels during the first 24 hours of ECMO. However, at 48 hours, observed concentrations exceeded those predicted, suggesting accumulation. We conclude that in the first 24 hours of ECMO, because of an expanded circulating volume and sequestration by the circuit, significantly more midazolam is required to achieve adequate sedation. Subsequently, and because of circuit saturation, maintenance doses should be reduced.

Safety of benzodiazepines in newborns

BACKGROUND

Benzodiazepines are being used in neonatal intensive care units for sedation and control of seizures. However, anecdotal reports suggest that their use in infants may be associated with serious adverse effects (AEs).

OBJECTIVE

To determine the incidence of AEs from benzodiazepine use in preterm and full-term infants.

METHODS

Retrospective chart review of 63 infants who received benzodiazepines as a sedative or anticonvulsant over a 16-month period.

RESULTS

Mean +/- SD gestational age of the infants was 33.1 +/- 6.2 weeks, and birth weight was 2.3 +/- 1.2 kg. Median (range) postnatal age at commencement of drug administration was 19 (5-54) days. Forty-one infants received lorazepam, 8 received midazolam, and 14 received both. Ten (16%) of the infants had 14 documented adverse events: seizures (n = 6), hypotension (n = 5), and respiratory depression (n = 3). Using a validated adverse drug reaction probability scale, a probable association with benzodiazepine use was demonstrated in 12 of the AEs. Due to the retrospective nature of the data, a score for definite association was not attainable. Anticonvulsant administration was required for 4 of 6 infants and, in all cases of respiratory depression, ventilatory support was initiated or increased. Two cases of significant hypotension were treated with inotropes. There was no statistically significant correlation between AEs and benzodiazepine dose or concomitant use of inotropes or analgesics (morphine), although most infants had underlying medical conditions or received multiple drugs that may have predisposed them to experience AEs.

CONCLUSIONS

Administration of benzodiazepines was frequently associated with AEs in full-term and preterm infants. It is possible that underlying illnesses and concomitant drug use predisposed these effects. Until the benefit-to-risk ratio is determined by further studies, judicious use of benzodiazepines is recommended in this vulnerable population.

Ketamine for procedural pain relief in newborn infants

AIM

To assess the suitability of ketamine for relief of pain caused by tracheal suction during ventilator treatment in newborn infants.

STUDY DESIGN

In a randomised, double blind, cross over trial, 16 newborn infants received placebo or 0.5, 1, or 2 mg/kg ketamine as two minute infusions in random order five minutes before four separate endotracheal suctions, with intervals of at least 12 hours.

RESULTS

Mean (SD) plasma ketamine concentration increased linearly with the dose (103 (49), 189 (75), and 379 (97) ng/ml after 0.5, 1, and 2 mg/kg respectively). Heart rate decreased significantly only after 2 mg/kg ketamine (-7 (10) beats/min, p = 0.029 v placebo). The increases in heart rate, arterial blood pressure, and pain score in response to tracheal suction during the placebo phase (11 (23) beats/min, p = 0.065; 6 (7) mm Hg, p = 0.004; 3.5 (interquartile range (IQR) 2.75-5) points, p = 0.001) were not attenuated by 0.5 or 2 mg/kg ketamine. However, 1 mg/kg ketamine attenuated the increase in pain score (1 (IQR 0.75-4.25) points, p = 0.043 v placebo), but not in heart rate (7 (23) beats/min) or blood pressure (7 (9) mm Hg).

CONCLUSION

None of the doses of ketamine attenuated the changes in heart rate or blood pressure caused by suction, and only with a dose of 1 mg/kg was the suction induced pain moderately reduced. Thus infusion of ketamine at the doses used appears to be an ineffective method of relieving the pain caused by endotracheal suction.

Neonatal seizures and neonatal epileptic syndromes

The neonatal period is defined as the first 28 days of life of a term infant; for premature infants the limit of this period is 44 completed weeks of the infant's conceptional age (CA)-defined as the chronological age plus gestational age (GA) at birth. The clinical and electroencephalographic (EEG) manifestations of seizures during this period are determined primarily by the development features of the immature brain at the time of seizure onset, but are also related to the type and diversity of etiologies and risk-factors for seizures neonates may face early in life. Neonatal seizures may be strikingly different from the clinical and electrical seizures of older children and adults. In addition, findings from basic science investigations suggest that immature animals are more likely to experience seizures in response to injury than more mature animals, although the developing brain is less susceptible to seizure-induced injury.