Efficacy of continuous versus intermittent morphine administration after major surgery in 0-3-year-old infants; a double-blind randomized controlled trial

The influence of intensive care treatment in infancy on cortisol levels in childhood and adolescence

BACKGROUND

Infants admitted to the intensive care unit experience numerous early-life stressors, which may have long-term effects on hypothalamic-pituitary-adrenal axis functioning.

AIMS

To determine the effects of intensive care treatment and related exposure to stress, pain, and opioids in infancy on cortisol levels in childhood and adolescence.

STUDY DESIGN

Cross-sectional study.

SUBJECTS

Children and adolescents aged 8 to 18 years with a history of intensive care treatment in infancy and healthy controls. The intensive care treatment cohort consisted of four subgroups with varying levels of exposure to stress, pain, and opioids in infancy. They received either mechanical ventilation, extracorporeal membrane oxygenation, major surgery, or excochleation of a giant congenital melanocytic nevus.

OUTCOME MEASURES

Between-group differences in stress reactivity to a study visit consisting of pain threshold testing and an MRI examination and diurnal cortisol levels, as measured in saliva.

RESULTS

After adjustment for age, sex, and gestational age, the diurnal cortisol output (AUCg) in the overall intensive care group (N = 76) was 18 % (approximately 1000 nmol/L) (95 % CI [-31 %, -3 %], P = 0.022) lower than that in the control group (N = 67). Cortisol awakening response, diurnal decline, and stress reactivity neither differed significantly between the overall intensive care group and control group, nor between the intensive care subgroups and control group.

CONCLUSION

Children and adolescents with a history of intensive care treatment in infancy have similar cortisol profiles to those of healthy controls, except for an 18 % lower diurnal cortisol output. The clinical relevance of this reduction is yet to be determined.

The physiology, assessment, and treatment of neonatal pain

Studies have clearly shown that development of pain receptors starts as early as 20-weeks' gestation. Despite contrary belief, the human fetus develops a similar number of receptive pain fibers as seen in adults. These receptors' maturation is based on response to sensory stimuli received after birth which makes the NICU a critical place for developing central nervous system's pain perception. In practice, the assessment of pain relies mostly on bedside staff. In this review we will discuss the various developing features of pain pathways in the neonatal brain and the modification of pain perception secondary to various interactions immediately after birth. We also discuss the various tools utilized in the NICU for pain assessment that rely on physiological and behavioral patterns. Finally, we address the management of pain in the NICU by either pharmacological or non-pharmacological intervention while highlighting potential benefits, disadvantages, and situations where one may be preferred over another.

Systemic opioid regimens for postoperative pain in neonates

BACKGROUND

Postoperative pain clinical management in neonates has always been a challenging medical issue. Worldwide, several systemic opioid regimens are available for pediatricians, neonatologists, and general practitioners to control pain in neonates undergoing surgical procedures. However, the most effective and safe regimen is still unknown in the current body of literature.

OBJECTIVES

To determine the effects of different regimens of systemic opioid analgesics in neonates submitted to surgery on all-cause mortality, pain, and significant neurodevelopmental disability. Potentially assessed regimens might include: different doses of the same opioid, different routes of administration of the same opioid, continuous infusion versus bolus administration, or 'as needed' administration versus 'as scheduled' administration.

SEARCH METHODS

Searches were conducted in June 2022 using the following databases: Cochrane Central Register of Controlled Trials [CENTRAL], PubMed, and CINAHL. Trial registration records were identified via CENTRAL and an independent search of the ISRCTN registry.

SELECTION CRITERIA

We included randomized controlled trials (RCTs), quasi-randomized, cluster-randomized, and cross-over controlled trials evaluating systemic opioid regimens' effects on postoperative pain in neonates (pre-term or full-term). We considered suitable for inclusion: I) studies evaluating different doses of the same opioid; 2) studies evaluating different routes of administration of the same opioid; 3) studies evaluating the effectiveness of continuous infusion versus bolus infusion; and 4) studies establishing an assessment of an 'as needed' administration versus 'as scheduled' administration.

DATA COLLECTION AND ANALYSIS

According to Cochrane methods, two investigators independently screened retrieved records, extracted data, and appraised the risk of bias. We stratified meta-analysis by the type of intervention: studies evaluating the use of opioids for postoperative pain in neonates through continuous infusion versus bolus infusion and studies assessing the 'as needed' administration versus 'as scheduled' administration. We used the fixed-effect model with risk ratio (RR) for dichotomous data and mean difference (MD), standardized mean difference (SMD), median, and interquartile range (IQR) for continuous data. Finally, we used the GRADEpro approach for primary outcomes to evaluate the quality of the evidence across included studies.

MAIN RESULTS

In this review, we included seven randomized controlled clinical trials (504 infants) from 1996 to 2020. We identified no studies comparing different doses of the same opioid, or different routes. The administration of continuous opioid infusion versus bolus administration of opioids was evaluated in six studies, while one study compared 'as needed' versus 'as scheduled' administration of morphine given by parents or nurses. Overall, the effectiveness of continuous infusion of opioids over bolus infusion as measured by the visual analog scale (MD 0.00, 95% confidence interval (CI) -0.23 to 0.23; 133 participants, 2 studies; I² = 0); or using the COMFORT scale (MD -0.07, 95% CI -0.89 to 0.75; 133 participants, 2 studies; I² = 0), remains unclear due to study designs' limitations, such as the unclear risk of attrition, reporting bias, and imprecision among reported results (very low certainty of the evidence).  None of the included studies reported data on other clinically important outcomes such as all-cause mortality rate during hospitalization, major neurodevelopmental disability, the incidence of severe retinopathy of prematurity or intraventricular hemorrhage, and cognitive- and educational-related outcomes.  AUTHORS' CONCLUSIONS: Limited evidence is available on continuous infusion compared to intermittent boluses of systemic opioids. We are uncertain whether continuous opioid infusion reduces pain compared with intermittent opioid boluses; none of the studies reported the other primary outcomes of this review, i.e. all-cause mortality during initial hospitalization, significant neurodevelopmental disability, or cognitive and educational outcomes among children older than five years old. Only one small study reported on morphine infusion with parent- or nurse-controlled analgesia.

Systemic opioid regimens for postoperative pain in neonates

BACKGROUND

Postoperative pain clinical management in neonates has always been a challenging medical issue. Worldwide, several systemic opioid regimens are available for pediatricians, neonatologists, and general practitioners to control pain in neonates undergoing surgical procedures. However, the most effective and safe regimen is still unknown in the current body of literature.

OBJECTIVES

To determine the effects of different regimens of systemic opioid analgesics in neonates submitted to surgery on all-cause mortality, pain, and significant neurodevelopmental disability. Potentially assessed regimens might include: different doses of the same opioid, different routes of administration of the same opioid, continuous infusion versus bolus administration, or 'as needed' administration versus 'as scheduled' administration.

SEARCH METHODS

Searches were conducted in June 2022 using the following databases: Cochrane Central Register of Controlled Trials [CENTRAL], PubMed, and CINAHL. Trial registration records were identified via CENTRAL and an independent search of the ISRCTN registry.

SELECTION CRITERIA

We included randomized controlled trials (RCTs), quasi-randomized, cluster-randomized, and cross-over controlled trials evaluating systemic opioid regimens' effects on postoperative pain in neonates (pre-term or full-term). We considered suitable for inclusion: I) studies evaluating different doses of the same opioid; 2) studies evaluating different routes of administration of the same opioid; 3) studies evaluating the effectiveness of continuous infusion versus bolus infusion; and 4) studies establishing an assessment of an 'as needed' administration versus 'as scheduled' administration.

DATA COLLECTION AND ANALYSIS

According to Cochrane methods, two investigators independently screened retrieved records, extracted data, and appraised the risk of bias. We stratified meta-analysis by the type of intervention: studies evaluating the use of opioids for postoperative pain in neonates through continuous infusion versus bolus infusion and studies assessing the 'as needed' administration versus 'as scheduled' administration. We used the fixed-effect model with risk ratio (RR) for dichotomous data and mean difference (MD), standardized mean difference (SMD), median, and interquartile range (IQR) for continuous data. Finally, we used the GRADEpro approach for primary outcomes to evaluate the quality of the evidence across included studies.

MAIN RESULTS

In this review, we included seven randomized controlled clinical trials (504 infants) from 1996 to 2020. We identified no studies comparing different doses of the same opioid, or different routes. The administration of continuous opioid infusion versus bolus administration of opioids was evaluated in six studies, while one study compared 'as needed' versus 'as scheduled' administration of morphine given by parents or nurses. Overall, the effectiveness of continuous infusion of opioids over bolus infusion as measured by the visual analog scale (MD 0.00, 95% confidence interval (CI) -0.23 to 0.23; 133 participants, 2 studies; I² = 0); or using the COMFORT scale (MD -0.07, 95% CI -0.89 to 0.75; 133 participants, 2 studies; I² = 0), remains unclear due to study designs' limitations, such as the unclear risk of attrition, reporting bias, and imprecision among reported results (very low certainty of the evidence).  None of the included studies reported data on other clinically important outcomes such as all-cause mortality rate during hospitalization, major neurodevelopmental disability, the incidence of severe retinopathy of prematurity or intraventricular hemorrhage, and cognitive- and educational-related outcomes.  AUTHORS' CONCLUSIONS: Limited evidence is available on continuous infusion compared to intermittent boluses of systemic opioids. We are uncertain whether continuous opioid infusion reduces pain compared with intermittent opioid boluses; none of the studies reported the other primary outcomes of this review, i.e. all-cause mortality during initial hospitalization, significant neurodevelopmental disability, or cognitive and educational outcomes among children older than five years old. Only one small study reported on morphine infusion with parent- or nurse-controlled analgesia.

Neonatal Pain, Opioid, and Anesthetic Exposure; What Remains in the Human Brain After the Wheels of Time?

OBJECTIVE

To evaluate possible negative long-term effects of neonatal exposure to pain, opioids and anesthetics in children and adolescents.

STUDY DESIGN

We studied five unique groups of children recruited from well-documented neonatal cohorts with a history of neonatal exposure to pain, opioids or anesthetics at different points along the continuum from no pain to intense pain and from no opioid exposure to very high opioid exposure in the presence or absence of anesthetics. We evaluated children who underwent major surgery (group 1 and 2), extracorporeal membrane oxygenation (group 3), preterm birth (group 4) and prenatal opioid exposure (group 5) in comparison to healthy controls. Neuropsychological functioning, thermal detection and pain thresholds and high-resolution structural and task-based functional magnetic resonance imaging during pain were assessed. In total 94 cases were included and compared to their own control groups.

RESULTS

Children and adolescents in groups 3 and 5 showed worse neuropsychological functioning after high opioid exposure. A thicker cortex was found in group 1 (pain, opioid and anesthetic exposure) in only the left rostral-middle-frontal-cortex compared to controls. We found no differences in other brain volumes, pain thresholds or brain activity during pain in pain related brain regions between the other groups and their controls.

CONCLUSIONS

No major effects of neonatal pain, opioid or anesthetic exposure were observed in humans 8-19 years after exposure in early life, apart from neuropsychological effects in the groups with the highest opioid exposure that warrants further investigation. Studies with larger sample sizes are needed to confirm our findings and test for less pronounced differences between exposed and unexposed children.

Design and reporting characteristics of clinical trials investigating sedation practices in the paediatric intensive care unit: a scoping review by SCEPTER (Sedation Consortium on Endpoints and Procedures for Treatment, Education and Research)

OBJECTIVES

To conduct a scoping review of sedation clinical trials in the paediatric intensive care setting and summarise key methodological elements.

DESIGN

Scoping review.

DATA SOURCES

PubMed, Embase, Cumulative Index to Nursing and Allied Health Literature and grey references including ClinicalTrials.gov from database inception to 3 August 2021.

STUDY SELECTION

All human trials in the English language related to sedation in paediatric critically ill patients were included. After title and abstract screening, full-text review was performed. 29 trials were eligible for final analysis.

DATA EXTRACTION

A coding manual was developed and pretested. Trial characteristics were double extracted.

RESULTS

The majority of trials were single centre (22/29, 75.9%), parallel group superiority (17/29, 58.6%), double-blinded (18/29, 62.1%) and conducted in an academic setting (29/29, 100.0%). Trial enrolment (≥90% planned sample size) was achieved in 65.5% of trials (19/29), and retention (≥90% enrolled subjects) in 72.4% of trials (21/29). Protocol violations were reported in nine trials (31.0%). The most commonly studied cohorts were mechanically ventilated patients (28/29, 96.6%) and postsurgical patients (11/29, 37.9%) with inclusion criteria for age ranging from 0±0.5 to 15.0±7.3 years (median±IQR). The median age of enrolled patients was 1.7 years (IQR=4.4 years). Patients excluded from trials were those with neurological impairment (21/29, 72.4%), complex disease (20/29, 69.0%) or receipt of neuromuscular blockade (10/29, 34.5%). Trials evaluated drugs/protocols for sedation management (20/29, 69.0%), weaning (3/29, 10.3%), daily interruption (3/29, 10.3%) or protocolisation (3/29, 10.3%). Primary outcome measures were heterogeneous, as were assessment instruments and follow-up durations.

CONCLUSIONS

There is substantial heterogeneity in methodological approach in clinical trials evaluating sedation in critically ill paediatric patients. These results provide a basis for the design of future clinical trials to improve the quality of trial data and aid in the development of sedation-related clinical guidelines.

Quantifying the pharmacodynamics of morphine in the treatment of postoperative pain in preverbal children

While the pharmacokinetics of morphine in children have been studied extensively, little is known about the pharmacodynamics of morphine in this population. Here, we quantified the concentration‐effect relationship of morphine for postoperative pain in preverbal children between 0 and 3 years of age. For this, we applied item response theory modeling in the pharmacokinetic/pharmacodynamic analysis of COMFORT‐Behavior (COMFORT‐B) scale data from 2 previous clinical studies. In the model, we identified a sigmoid maximal efficacy model for the effect of morphine and found that in 26% of children, increasing morphine concentrations were not associated with lower pain scores (nonresponders to morphine up‐titration). In responders to morphine up‐titration, the COMFORT‐B score slowly decreases with increasing morphine concentrations at morphine concentrations >20 ng/mL. In nonresponding children, no decrease in COMFORT‐B score is expected. In general, lower baseline COMFORT‐B scores (2.1 points on average) in younger children (postnatal age <10.3 days) were found. Based on the model, we conclude that the percentage of children at a desirable COMFORT‐B score is maximized at a morphine concentration between 5 and 30 ng/mL for children aged <10 days, and between 5 and 40 ng/mL for children >10 days. These findings support a dosing regimen previously suggested by Krekels et al, which would put >95% of patients within this morphine target concentration range at steady state. Our modeling approach provides a promising platform for pharmacodynamic research of analgesics and sedatives in children.

A Pilot Randomized Controlled Trial of Outcomes Associated with Parent-Nurse Controlled Analgesia vs. Continuous Opioid Infusion in the Neonatal Intensive Care Unit

PURPOSE

Prospectively compare parent/nurse controlled analgesia (PNCA) to continuous opioid infusion (COI) in the post-operative neonatal intensive care unit (NICU) population.

DESIGN/METHODS

A randomized controlled trial compared neonates treated with morphine PNCA to those treated with morphine COI. The primary outcome was average opioid consumption up to 3 post-operative days. Secondary outcomes included 1) pain intensity, 2) adverse events that may be directly related to opioid consumption, and 3) parent and nurse satisfaction.

RESULTS

The sample consisted of 25 post-operative neonates and young infants randomized to either morphine PNCA (n = 16) or COI (n = 9). Groups differed significantly on daily opioid consumption, with the PNCA group receiving significantly less opioid (P = .02). Groups did not differ on average pain score or frequency of adverse events (P values > .05). Parents in both groups were satisfied with their infant's pain management and parents in the PNCA group were slightly more satisfied with their level of involvement (P = .03). Groups did not differ in nursing satisfaction.

CONCLUSIONS

PNCA may be an effective alternative to COI for pain management in the NICU population. This method may also substantially reduce opioid consumption, provide more individualized care, and improve parent satisfaction with their level of participation.

CLINICAL IMPLICATIONS

Patients in the NICU represent one of our most vulnerable patient populations. As nurses strive to provide safe and effective pain management, results of this study suggest PNCA may allow nurses to maintain their patients' comfort while providing less opioid and potentially improving parental perception of involvement.

STUDY TYPE

Treatment study.

LEVEL OF EVIDENCE

I.

Analgesia, sedation, and delirium in pediatric surgical critical care

The alleviation of discomfort and distress is an essential component of the management of critically ill surgical patients. Pain and anxiety have multifocal etiologies that may be related to an underlying disease or surgical procedure, ongoing medical therapy, invasive monitors, an unfamiliar, complex and chaotic environment, as well as fear. Pharmacologic and non-pharmacologic therapies have complex risk benefit profiles. A fundamental understanding of analgesia, sedation, and delirium is essential for optimizing important outcomes in critically ill pediatric surgical patients. There has been a recent emphasis on goal directed, evidence based, and patient-centered management of the physical and psychological needs of these children. The purpose of this article is to review and summarize recent advances and describe current practice of these important subjects in the pediatric surgical intensive care environment.

Development of the Japanese version of the State Behavioral Scale for critically ill children

Aims

The State Behavioral Scale (SBS) was developed to assess sedation states, including agitation, in pediatric patients on mechanical ventilation. The purpose of this study was to determine the reliability and validity of a back‐translated Japanese version of the SBS.

Methods

Translation was done by the back‐translation method followed by a prospective study in a Japanese intensive care unit. For reliability, a nurse/researcher pair evaluated SBS along eight dimensions (respiratory drive, response to ventilation, coughing, best response to stimulation, attentiveness to care provider, tolerance to care, consolability, and movement after consoled). For validity, SBS scores were compared to the Richmond Agitation–Sedation Scale and a visual analog scale (VAS).

Results

The original author approved the back‐translated SBS. Thirty‐one patients aged 0 weeks to 8 years were evaluated from 59 total critical pediatric patient encounters. The researcher and nurse SBS scores demonstrated excellent inter‐rater reliability (weighted κ = 0.96, 95% CI 0.92–0.99). In addition, there was a very strong correlation between the researcher and nurse VAS scores (ρ = 0.80, P < 0.001). Weighted kappa coefficients for the eight dimensions ranged from 0.71 (95% confidence interval, 0.55–0.88; consolability) to 0.89 (95% confidence interval, 0.80–0.98; best response to stimulation). In validity testing, nurse SBS and nurse VAS scores were strongly correlated (ρ = 0.80, P < 0.001) with the researcher SBS and researcher Richmond Agitation–Sedation Scale scores (ρ = 0.91, P < 0.001).

Conclusion

This study suggests that our Japanese version of the SBS is valid and reliable for evaluating sedation for critically ill children.

Predictive Performance of a Recently Developed Population Pharmacokinetic Model for Morphine and its Metabolites in New Datasets of (Preterm) Neonates, Infants and Children

BACKGROUND AND OBJECTIVE

Model validation procedures are crucial when models are to be used to develop new dosing algorithms. In this study, the predictive performance of a previously published paediatric population pharmacokinetic model for morphine and its metabolites in children younger than 3 years (original model) is studied in new datasets that were not used to develop the original model.

METHODS

Six external datasets including neonates and infants up to 1 year were obtained from four different research centres. These datasets contained postoperative patients, ventilated patients and patients on extracorporeal membrane oxygenation (ECMO) treatment. Basic observed versus predicted plots, normalized prediction distribution error analysis, model refitting, bootstrap analysis, subpopulation analysis and a literature comparison of clearance predictions were performed with the new datasets to evaluate the predictive performance of the original morphine pharmacokinetic model.

RESULTS

The original model was found to be stable and the parameter estimates were found to be precise. The concentrations predicted by the original model were in good agreement with the observed concentrations in the four datasets from postoperative and ventilated patients, and the model-predicted clearances in these datasets were in agreement with literature values. In the datasets from patients on ECMO treatment with continuous venovenous haemofiltration (CVVH) the predictive performance of the model was good as well, whereas underprediction occurred, particularly for the metabolites, in patients on ECMO treatment without CVVH.

CONCLUSION

The predictive value of the original morphine pharmacokinetic model is demonstrated in new datasets by the use of six different validation and evaluation tools. It is herewith justified to undertake a proof-of-principle approach in the development of rational dosing recommendations - namely, performing a prospective clinical trial in which the model-based dosing algorithm is clinically evaluated.

Neonatal pain management

Pain management in the neonatal ICU remains challenging for many clinicians and in many complex care circumstances. The authors review general pain management principles and address the use of pain scales, non-pharmacologic management, and various agents that may be useful in general neonatal practice, procedurally, or at the end of life. Chronic pain and neonatal abstinence are also noted.

Difficulties with assessment and management of an infant's distress in the postoperative period: Optimising opportunities for interdisciplinary information-sharing

OBJECTIVES

The importance of accurate paediatric patient assessment is well established but under-utilised in managing postoperative medication regimens.

METHODS

Data for this case report were collected through observations of clinical practice, conduct of interviews, and retrieval of information from the medical record. This case report involving a hospitalised 1-year-old boy demonstrates the difficulties associated with assessing and managing postoperative distress, including pain and other clinical conditions related to the surgical procedure.

RESULTS

Postoperatively, there were difficulties in managing pain and an episode of over-sedation, occasioning opiate reversal with naloxone. In addition, he had decreasing oxygen saturation and increased work of breathing. X-ray showed changes consistent with either atelectasis or aspiration, and he was commenced on antibiotics. The patient experienced respiratory distress and required intervention from the medical emergency team.

CONCLUSION

This case demonstrated the importance of comprehensive assessment and careful consideration of alternative causes of an infant's distress using the results of assessment tools to aid decision-making. Communication moderates effective patient care, and more favourable outcomes could be achieved by optimising interdisciplinary information-sharing.

Paracetamol and morphine for infant and neonatal pain; still a long way to go?

INTRODUCTION

Pharmacologic pain management in newborns and infants is often based on limited scientific data. To close the knowledge gap, drug-related research in this population is increasingly supported by the authorities, but remains very challenging. This review summarizes the challenges of analgesic studies in newborns and infants on morphine and paracetamol (acetaminophen). Areas covered: Aspects such as the definition and multimodal character of pain are reflected to newborn infants. Specific problems addressed include defining pharmacodynamic endpoints, performing clinical trials in this population and assessing developmental changes in both pharmacokinetics and pharmacodynamics. Expert commentary: Neonatal and infant pain management research faces two major challenges: lack of clear biomarkers and very heterogeneous pharmacokinetics and pharmacodynamics of analgesics. There is a clear call for integral research addressing the multimodality of pain in this population and further developing population pharmacokinetic models towards physiology-based models.

Safety and efficacy of nurse-controlled analgesia in patients less than 1 year of age

Background

The management of acute pain presents unique challenges in the younger pediatric population. Although patient-controlled devices are frequently used in patients ≥6 years of age, alternative modes of analgesic delivery are needed in infants.

Objective

To examine the safety and efficacy of nurse-controlled analgesia (NCA) in neonates less than 1 year of age.

Methods

Data from patients <1 year of age receiving NCA as ordered by the Acute Pain Service at our institution were collected over a 5-year period and reviewed retrospectively. The primary outcomes were activation of the institution’s Rapid Response Team (RRT) or Code Blue, signifying severe adverse events. Pain score after NCA initiation was a secondary outcome.

Results

Among 338 girls and 431 boys, the most common opioid used for NCA was fentanyl, followed by morphine and hydromorphone. There were 39 (5%) cases involving RRT or Code Blue activation, of which only one (Code Blue) was activated due to a complication of NCA (apnea). Multivariable logistic regression demonstrated morphine NCA to be associated with greater odds of RRT activation (OR=3.29, 95% CI=1.35, 8.03, P=0.009) compared to fentanyl NCA. There were no statistically significant differences in pain scores after NCA initiation across NCA agents.

Conclusion

NCA is safe in neonates and infants, with comparable efficacy demonstrated for the three agents used. The elevated incidence of RRT activation in patients receiving morphine suggests caution in its use and consideration of alternative agents in this population.

Clinical recommendations for pain, sedation, withdrawal and delirium assessment in critically ill infants and children: an ESPNIC position statement for healthcare professionals

Background

This position statement provides clinical recommendations for the assessment of pain, level of sedation, iatrogenic withdrawal syndrome and delirium in critically ill infants and children. Admission to a neonatal or paediatric intensive care unit (NICU, PICU) exposes a child to a series of painful and stressful events. Accurate assessment of the presence of pain and non-pain-related distress (adequacy of sedation, iatrogenic withdrawal syndrome and delirium) is essential to good clinical management and to monitoring the effectiveness of interventions to relieve or prevent pain and distress in the individual patient.

Methods

A multidisciplinary group of experts was recruited from the members of the European Society of Paediatric and Neonatal Intensive Care (ESPNIC). The group formulated clinical questions regarding assessment of pain and non-pain-related distress in critically ill and nonverbal children, and searched the PubMed/Medline, CINAHL and Embase databases for studies describing the psychometric properties of assessment instruments. Furthermore, level of evidence of selected studies was assigned and recommendations were formulated, and grade or recommendations were added on the basis of the level of evidence.

Results

An ESPNIC position statement was drafted which provides clinical recommendations on assessment of pain (n = 5), distress and/or level of sedation (n = 4), iatrogenic withdrawal syndrome (n = 3) and delirium (n = 3). These recommendations were based on the available evidence and consensus amongst the experts and other members of ESPNIC.

Conclusions

This multidisciplinary ESPNIC position statement guides professionals in the assessment and reassessment of the effectiveness of treatment interventions for pain, distress, inadequate sedation, withdrawal syndrome and delirium.

Electronic supplementary material

The online version of this article (doi:10.1007/s00134-016-4344-1) contains supplementary material, which is available to authorized users.

Rescue morphine in mechanically ventilated newborns associated with combined OPRM1 and COMT genotype

AIM

Determine whether SNPs of OPRM1 118A>G (asn(40)asp), COMT 472G>A (val(158)met) and ARRB2 8622C>T are associated with morphine rescue in newborns on mechanical ventilation.

MATERIALS & METHODS

This is a pharmacogenetic analysis of a randomized controlled trial in (pre)term newborns (n = 64) at a level III Neonatal Intensive Care Unit (NICU) who received placebo infusion and for whom need and dose for rescue morphine was documented.

RESULTS

For OPRM1 and COMT separately, the expected risk for rescue morphine or morphine dose was not significantly increased. However, the combined OPRM1/COMT 'high-risk' genotype lead to a significant association with the need for rescue (OR: 5.12; 95% CI: 1.12-23.3; p = 0.035). No association was found between OPRM1/COMT 'high-risk' genotype and total morphine dose administered.

CONCLUSION

Combined OPRM1 118A>G and COMT 472G>A genotype might serve as a predictor for the need of rescue morphine in premature and term newborns on mechanical ventilation.

Ethics of drug research in the pediatric intensive care unit

Critical illness and treatment modalities change pharmacokinetics and pharmacodynamics of medications used in critically ill children, in addition to age-related changes in drug disposition and effect. Hence, to ensure effective and safe drug therapy, research in this population is urgently needed. However, conducting research in the vulnerable population of the pediatric intensive care unit (PICU) presents with ethical challenges. This article addresses the main ethical issues specific to drug research in these critically ill children and proposes several solutions. The extraordinary environment of the PICU raises specific challenges to the design and conduct of research. The need for proxy consent of parents (or legal guardians) and the stress-inducing physical environment may threaten informed consent. The informed consent process is challenging because emergency research reduces or even eliminates the time to seek consent. Moreover, parental anxiety may impede adequate understanding and generate misconceptions. Alternative forms of consent have been developed taking into account the unpredictable reality of the acute critical care environment. As with any research in children, the burden and risk should be minimized. Recent developments in sample collection and analysis as well as pharmacokinetic analysis should be considered in the design of studies. Despite the difficulties inherent to drug research in critically ill children, methods are available to conduct ethically sound research resulting in relevant and generalizable data. This should motivate the PICU community to commit to drug research to ultimately provide the right drug at the right dose for every individual child.

Pain management in newborns

As a standard of care for preterm/term newborns effective pain management may improve their clinical and neurodevelopmental outcomes. Neonatal pain is assessed using context-specific, validated, and objective pain methods, despite the limitations of currently available tools. Therapeutic approaches reducing invasive procedures and using pharmacologic, behavioral, or environmental measures are used to manage neonatal pain. Nonpharmacologic approaches like kangaroo care, facilitated tucking, non-nutritive sucking, sucrose, and others can be used for procedural pain or adjunctive therapy. Local/topical anesthetics, opioids, NSAIDs/acetaminophen and other sedative/anesthetic agents can be incorporated into NICU protocols for managing moderate/severe pain or distress in all newborns.

Is there an alternative to continuous opioid infusion for neonatal pain control? A preliminary report of parent/nurse-controlled analgesia in the neonatal intensive care unit

BACKGROUND

Continuous opioid infusion (COI) remains the mainstay of analgesic therapy in the neonatal intensive care unit (NICU). Parent/nurse-controlled analgesia (PNCA) has been accepted as safe and effective for pediatric patients, but few reports include use in neonates. This study sought to compare outcomes of PNCA and COI in postsurgical neonates and young infants.

METHODS

Twenty infants treated with morphine PNCA were retrospectively compared with 13 infants treated with fentanyl COI in a Midwestern pediatric hospital in the United States. Outcome measures included opioid consumption, pain scores, frequency of adverse events, and subsequent methadone use.

RESULTS

The PNCA group (median 6.4 μg · kg(-1) · h(-1) morphine equivalents, range 0.0-31.4) received significantly less opioid (P < 0.001) than the COI group (median 40.0 μg · kg(-1) · h(-1) morphine equivalents; range 20.0-153.3), across postoperative days 0-3. Average daily pain scores (based on 0-10 scale) were low for both groups, but median scores differed nonetheless (0.8 PNCA vs 0.3 COI, P < 0.05). There was no significant difference in the frequency of adverse events or methadone use.

CONCLUSION

Results suggest PNCA may be a feasible and effective alternative to COI for pain management in postsurgical infants in the NICU. Results also suggest PNCA may provide more individualized care for this vulnerable population and in doing so, may potentially reduce opioid consumption; however, more studies are needed.

Developmental changes in morphine clearance across the entire paediatric age range are best described by a bodyweight-dependent exponent model

BACKGROUND AND OBJECTIVE

Morphine clearance has been successfully scaled from preterm neonates to 3-year-old children on the basis of a bodyweight-based exponential (BDE) function and age younger or older than 10 days. The aim of the current study was to characterize the developmental changes in morphine clearance across the entire paediatric age range.

METHODS

Morphine and morphine-3-glucuronide (M3G) concentration data from 358 (pre)term neonates, infants, children and adults, and morphine concentration data from 117 adolescents were analysed using NONMEM 7.2. Based on available data, two models were developed: I. using morphine data; II. using morphine and M3G data.

RESULTS

In model I, morphine clearance across the paediatric age range was very well described by a BDE function in which the allometric exponent decreased in a sigmoidal manner with bodyweight (BDE model) from 1.47 to 0.88, with half the decrease in exponent reached at 4.01 kg. In model II, the exponent for the formation and elimination clearance of M3G was found to decrease from 1.56 to 0.89 and from 1.06 to 0.61, with half the decrease reached at 3.89 and 4.87 kg, respectively. Using the BDE model, there was no need to use additional measures for size or age.

CONCLUSION

The BDE model was able to scale both total morphine clearance and glucuronidation clearance through the M3G pathway across all age ranges between (pre)term neonates and adults by allowing the allometric exponent to decrease across the paediatric age range from values higher than 1 for neonates to values lower than 1 for infants and children.

Evidence-based comfort care for neonates towards the end of life

The provision of care to the newborn or young infant at the end of life is primarily motivated by concern and compassion. When examining the evidence base for most interventions, it is lacking - but this is not unique to this aspect of neonatal care. Nevertheless, a redirection of care from cure-oriented and life-extending measures to comfort and limitations of life-sustaining technologic interventions requires the neonatologist to apply practical knowledge skillfully and with prudence. Clinicians can acknowledge that patient needs require managing their end-of-life symptoms now; neither these patients nor their families should have to wait for research to catch up to their current needs.

Pain status and sedation level in Chinese children after cardiac surgery: an observational study

AIMS AND OBJECTIVES

This study explored current pain status, sedation level and their trajectories in Chinese children after cardiac surgery. Background.  Pain and sedation management are fundamental care practices in the critical care setting, yet they both are frequently under-implemented for children after major surgery.

DESIGN

Repeated observational design.

METHODS

This study was conducted in a paediatric medical centre in Shanghai, China where 170 children who underwent cardiac surgery were recruited. Pain was measured with the face, legs, activity, cry, consolability scale and sedation levels with the COMFORT Behaviour Scale at 18 fixed time-points for three consecutive postoperative days. Results.  The study indicated that 95 children (55·9%) received continuous opioids for pain relief, and 61 children (35·9%) received no analgesics. Multiple sedatives were used for these children, including bolus phenobarbital for 117 children (68·8%), phenergan for 81 children (47·6%) and midazolam for three children (1·8%). The mean pain scores significantly decreased throughout the operation day (POD-0) to the 2nd postoperative day (POD-2) with the lowest score on POD-2. Less than 5% of pain assessments were identified as moderate to severe across all 2815 observations. The sedation scores significantly increased through POD-0 to POD-2 with the highest score on POD-2. The rate of over-sedation was 50·3% with <1% under-sedation occurring among all the observations. Results also suggested that the length of stay in the cardiac intensive care unit was a predictor of increased analgesic usage in the critical care setting (odds ratio: 1·72).

CONCLUSIONS

Usage of analgesic and sedative agents in cardiac intensive care unit was variable and children experienced low pain scores but a high rate of over-sedation, indicating that healthcare providers should address ways to improve postoperative pain and sedation management in this population.

RELEVANCE TO CLINICAL PRACTICE

The pain and sedation status for children after cardiac surgery changed across the postoperative days. Healthcare providers should be trained in the use of reliable tools to accurately monitor children's pain and sedation levels.

Morphine at "sub-analgesic" background infusion rate plus low-dose PCA bolus control pain better and is as safe as twice a bolus-only PCA regimen: a randomized, double blind study

Morphine for postoperative pain control is commonly titrated via intravenous patient-controlled analgesia (IV-PCA). An IV morphine background infusion is rarely used. We investigated whether analgesia is effectively attained and morphine consumption is reduced if PCA titration is coadjuvated by a continuous infusion protocol. Following colorectal cancer surgery, consenting patients were randomized to receive a minimal ("sub-analgesic") dose of morphine 0.01 mg/kg/h background infusion plus a 0.01 mg/kg bolus (BI), or a 1.5mg bolus-only morphine (B0) (bolus ratio ∼1:2). Bolus lockout time was 7 min in either case. All patients received 0.1mg/kg morphine before protocol initiation, and diclofenac 75 mg intramuscularly b.i.d. during the study period, lasting 48 h. Eighty-six patients (51 males, age 26-95 years) participated in the study. The total mean morphine consumption during the 48 h was 25% lower in the BI than in the B0 group (P<0.05). Although the former applied the PCA device for boluses 19% less than the latter (P<0.05), their pain score was lower (P<0.05) most of the time, and they reported greater satisfaction (P<0.05) on a 10-scale numerical rating score. Pre- and postoperative vital signs were similar for both groups. No patient depicted hypoxemia or lapsed into deep sedation. Four BI and three B0 patients required treatment for postoperative nausea and vomiting. One BI patient had transient pruritus and one B0 69-year individual became disoriented 24h into treatment; either event subsided soon after stopping their respective regimen without the need for treatment. The main conclusions of the results are that very-low-dose background morphine infusion combined with small-dose PCA boluses may provide better pain relief, lower morphine consumption, and minimal complication rate as a 1.5mg PCA bolus-only protocol.

Discomfort and pain in newborns with myelomeningocele: a prospective evaluation

OBJECTIVE

In a worldwide debate on deliberately terminating the lives of newborns, proponents point at newborns with very severe forms of myelomeningocele (MMC) and their assumed suffering, claiming there are no effective means of alleviating their distress. Nevertheless, the degree of discomfort and pain in these newborns has never been assessed in a structured manner.

METHODS

In a prospective cohort study, 28 consecutive newborns with MMC were included over a 5-year period and were followed up throughout their hospital stay for initial treatment. We created 2 disease severity groups on the basis of the Lorber criteria. The primary outcomes were discomfort and pain, assessed by simultaneously scoring 2 validated scales: the visual analog scale for pain and the Comfort Behavioral Scale for discomfort. These scores were coupled to a validated and evidence-based analgesia algorithm.

RESULTS

Overall, discomfort related to pain was measured in 3.3% of the scores. This percentage differed little between the preoperative and postoperative periods and did not significantly differ between newborns with less severe MMC and severe MMC (3.9% vs 2.8%; P = .3). The mean dosage of paracetamol was 35 mg/kg per day (95% confidence interval: 32-39); the mean dosage of morphine was 0.9 μg/kg per hour (95% confidence interval: 0.6 -1.2).

CONCLUSION

Over the length of their hospital stays for initial treatment, all newborns with MMC presented with low levels of discomfort and pain independent of disease severity and time frame.

Systematic evaluation of the descriptive and predictive performance of paediatric morphine population models

PURPOSE

A framework for the evaluation of paediatric population models is proposed and applied to two different paediatric population pharmacokinetic models for morphine. One covariate model was based on a systematic covariate analysis, the other on fixed allometric scaling principles.

METHODS

The six evaluation criteria in the framework were 1) number of parameters and condition number, 2) numerical diagnostics, 3) prediction-based diagnostics, 4) η-shrinkage, 5) simulation-based diagnostics, 6) diagnostics of individual and population parameter estimates versus covariates, including measurements of bias and precision of the population values compared to the observed individual values. The framework entails both an internal and external model evaluation procedure.

RESULTS

The application of the framework to the two models resulted in the detection of overparameterization and misleading diagnostics based on individual predictions caused by high shrinkage. The diagnostic of individual and population parameter estimates versus covariates proved to be highly informative in assessing obtained covariate relationships. Based on the framework, the systematic covariate model proved to be superior over the fixed allometric model in terms of predictive performance.

CONCLUSIONS

The proposed framework is suitable for the evaluation of paediatric (covariate) models and should be applied to corroborate the descriptive and predictive properties of these models.

Pharmacotherapy for acute pain in children: current practice and recent advances

INTRODUCTION

Acute pain in children may be undertreated. Improved understanding of developmental neurobiology and paediatric pharmacokinetics should facilitate better management of pharmacotherapy. The objective of this review is to discuss current paediatric practice and recent advances with these analgesic agents by using an evidence-based approach.

AREAS COVERED

Using PubMed an extensive literature review was conducted on the commonly used analgesic agents in children from 2000 to April 2010.

EXPERT OPINION

A multimodal analgesic regimen provides better pain control and functional outcome in children. The choice of pharmacological treatment is determined by the severity and type of pain. However, more research and evidence is required to determine the optimal drug combinations.

Morphine glucuronidation in preterm neonates, infants and children younger than 3 years

BACKGROUND AND OBJECTIVE

A considerable amount of drug use in children is still unlicensed or off-label. In order to derive rational dosing schemes, the influence of aging on glucuronidation capacity in newborns, including preterms, infants and children under the age of 3 years was studied using morphine and its major metabolites as a model drug.

METHODS

A population pharmacokinetic model was developed with the nonlinear mixed-effects modelling software NONMEM V, on the basis of 2159 concentrations of morphine and its glucuronides from 248 infants receiving intravenous morphine ranging in bodyweight from 500 g to 18 kg (median 2.8 kg). The model was internally validated using normalized prediction distribution errors.

RESULTS

Formation clearances of morphine to its glucuronides and elimination clearances of the glucuronides were found to be primarily influenced by bodyweight, which was parameterized using an allometric equation with an estimated exponential scaling factor of 1.44. Additionally, a postnatal age of less than 10 days was identified as a covariate for formation clearance to the glucuronides, independent of birthweight or postmenstrual age. Distribution volumes scaled linearly with bodyweight.

CONCLUSIONS

Model-based simulations show that in newborns, including preterms, infants and children under the age of 3 years, a loading dose in microg/kg and a maintenance dose expressed in microg/kg1.5/h, with a 50% reduction of the maintenance dose in newborns younger than 10 days, results in a narrow range of morphine and metabolite serum concentrations throughout the studied age range. Future pharmacodynamic investigations are needed to reveal target concentrations in this population, after which final dosing recommendations can be made.

The effect of continuous morphine administration on maternal plasma oxytocin concentration and uterine contractions after open fetal surgery

OBJECTIVE

A major complication of open fetal surgery is prematurity. We propose that fetal and maternal stress/pain after surgery may affect the concentration of circulating oxytocin and the frequency of uterine contractions, thus increasing the risk of preterm delivery. The objective of this study was to test whether continuous morphine sulfate administration after open fetal surgery has an effect on maternal plasma oxytocin concentration and the frequency of uterine contractions.

METHODS

An established time-pregnant primate model for open fetal surgery was used. From the time of surgery until the end of the three-day study period, three animals received prophylactic antibiotics, a bolus of indomethacin, and a bolus of morphine sulfate (group I). Three other animals received the same prophylactic antibiotics and an i.v. bolus of indomethacin, as well as a continuous i.v. infusion of morphine sulfate throughout the entire study period (group II). Maternal blood samples were collected to determine oxytocin plasma concentrations. Oxytocin was measured by radioimmunoassay. Uterine activity was continuously recorded through an amniotic fluid catheter and quantified as number of contractions (10 mmHg increase from base line in intrauterine pressure) per hour (UCs/h).

RESULTS

The mean maternal plasma oxytocin concentration was higher (p < 0.01) and the number of uterine contractions more frequent (p < 0.05) in the group of animals with intermittent doses of morphine than in the group that received morphine continuously.

CONCLUSIONS

These data suggest that maternal plasma oxytocin concentration and uterine activity after open fetal surgery may be related to inadequate maternal/fetal analgesia/sedation.

Efficacy of sedation regimens to facilitate mechanical ventilation in the pediatric intensive care unit: a systematic review

OBJECTIVE

Children admitted to pediatric intensive care units (PICUs) often receive sedatives to facilitate mechanical ventilation. However, despite their widespread use, data supporting appropriate dosing, safety, and optimal regimens for sedation during mechanical ventilation are lacking. Therefore, we conducted a systematic review of published data regarding efficacy of sedation to facilitate mechanical ventilation in PICU patients. Our primary objective was to identify and evaluate the quality of evidence supporting sedatives used in PICUs for this purpose.

DATA SOURCES

We searched MEDLINE, EMBASE, and The Cochrane Registry of Clinical Trials from 1966 to June 2008 to identify published articles evaluating sedation regimens to facilitate mechanical ventilation in PICU patients.

STUDY SELECTION

We included only those studies of intubated PICU or pediatric cardiac intensive care unit patients receiving pharmacologic agents to facilitate mechanical ventilation that reported quality of sedation as an outcome.

DATA EXTRACTION

We analyzed studies separately for study type and by agents being studied. Studies were appraised using criteria of particular importance for reviews evaluating sedatives.

DATA SYNTHESIS

Our search strategy yielded 39 studies, including 3 randomized trials, 15 cohort studies, and 21 cases series or reports. The 39 studies evaluated a total of 39 different sedation regimens, with 21 different scoring systems, in a total of 901 PICU/cardiac intensive care unit patients ranging in age from 3 days to 19 years old. Most of the studies were small (<30 patients), and only four studies compared one or more agents to another. Few studies thoroughly evaluated drug safety, and only one study met all quality criteria.

CONCLUSIONS

Despite the widespread use of sedatives to facilitate mechanical ventilation in the PICU, we found that high-quality evidence to guide clinical practice is still limited. Pediatric randomized, controlled trials with reproducible methods and assessment of drug safety are needed.

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.

Tolerance, opioid-induced allodynia and withdrawal associated allodynia in infant and young rats

Our laboratory has previously characterized age-dependent changes in nociception upon acute morphine withdrawal. This study characterizes changes in mechanical and thermal nociception following acute, intermittent, or continuous morphine administration in infant (postnatal days 5-8) and young (postnatal days 19-21) rats. Morphine was given as a single acute administration (AM), intermittently twice a day for 3 days (IM), or continuously for 72 h via pump (CM). AM did not produce long-term changes in mechanical or thermal nociception in either infant or young rats. CM produced changes in mechanical nociception that included the development of tolerance, opioid-induced mechanical allodynia and withdrawal-associated mechanical allodynia in young rats, but only tolerance and a prolonged withdrawal-associated mechanical allodynia in infant rats. IM produced withdrawal-associated mechanical allodynia in both infant and young rats. Measuring paw withdrawal responses to thermal stimuli, infant and young rats showed tolerance without opioid-induced thermal hyperalgesia or withdrawal-associated thermal hyperalgesia following CM. In contrast to CM, withdrawal-associated thermal hyperalgesia was seen in both ages following IM. In conclusion, CM versus IM differentially modified mechanical and thermal nociception, suggesting that opioid-dependent thermal hyperalgesia and mechanical allodynia can be dissociated from each other in infant and young rats. Furthermore, tolerance, opioid-induced hypersensitivity, and withdrawal-associated hypersensitivity are age-specific and may be mediated by distinct mechanisms.

Pain control: opioid dosing, population kinetics and side-effects

Neonates undergoing invasive procedures, postoperative pain or ventilatory support commonly receive opioids for treating pain and stress. Randomized clinical trials have examined the benefits and adverse effects of morphine or fentanyl for ventilated neonates and other indications. This paper summarizes the current evidence for opioid dosing in newborns, reviews their side-effects and explains the use of population kinetics and non-linear mixed-effects modeling to analyze the data from clinical trials. Opioid use should be reserved for severe pain postoperatively or during intensive care in neonates, using continuous infusions rather than intermittent boluses. The safety and efficacy data from prolonged opioid use, particularly on the long-term outcomes of neonates, is still lacking. The pharmacodynamics and pharmacogenetics of opioid use in infancy needs further investigation, using non-linear mixed-effects models to drive individualized therapy. The current interest in opioid research will reap rich dividends in providing pain relief for neonates and avoiding dangerous side effects.

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.

Summary proceedings from the neonatal pain-control group

Recent advances in neurobiology and clinical medicine have established that the fetus and newborn may experience acute, established, and chronic pain. They respond to such noxious stimuli by a series of complex biochemical, physiologic, and behavioral alterations. Studies have concluded that controlling pain experience is beneficial with respect to short-term and perhaps long-term outcomes. Yet, pain-control measures are adopted infrequently because of unresolved scientific issues and lack of appreciation for the need for control of pain and its long-term sequelae during the critical phases of neurologic maturation in the preterm and term newborn. The neonatal pain-control group, as part of the Newborn Drug Development Initiative (NDDI) Workshop I, addressed these concerns. The specific issues addressed were (1) management of pain associated with invasive procedures, (2) provision of sedation and analgesia during mechanical ventilation, and (3) mitigation of pain and stress responses during and after surgery in the newborn infant. The cross-cutting themes addressed within each category included (1) clinical-trial designs, (2) drug prioritization, (3) ethical constraints, (4) gaps in our knowledge, and (5) future research needs. This article provides a summary of the discussions and deliberations. Full-length articles on procedural pain, sedation and analgesia for ventilated infants, perioperative pain, and study designs for neonatal pain research were published in Clinical Therapeutics (June 2005).

The effects of early pain experience in neonates on pain responses in infancy and childhood

Iatrogenic pain is commonplace in newborn infants yet we know very little about its long-term effects. This article reviews the evidence for and against the suggestion that painful procedures experienced in the perinatal period influence subsequent pain responses in infancy or in childhood. The evidence suggests that early experiences with pain are associated with altered pain responses later in infancy. The direction of the altered response depends, in part, on the infant's developmental stage (full-term vs preterm), and his or her cumulative experience with pain. Preterm infants that are hospitalized as neonates and subjected to painful procedures appear to have a dampened response to painful procedures later in infancy. Full-term neonates exposed to extreme stress during delivery, or to a surgical procedure, react to later noxious procedures with heightened behavioral responsiveness. Studies in which analgesic agents (local anesthetics or opioids) have been administered prior to noxious procedures demonstrate less procedural pain and a reduction in the magnitude of long-term changes in pain behaviors. The precise determinants of these changes, their extent, and their permanence are not known but they appear to involve noxious stimulus-induced peripheral and central sensitization, as well as classical conditioning.

[Which sedation scale should be used in the paediatric intensive care unit? A comparative prospective study]

OBJECTIVES

To compare pain and sedation assessments by nurses undertaken with the Objective Pain Scale (OPS) and a Visual Analogue Scale (VAS) to the current reference scale for paediatric intensive care that is the COMFORT scale. To compare the unmodified COMFORT scale to a COMFORT "behaviour" scale which does not include physiologic items. To evaluate the ease of use of these scales.

METHODS

This prospective observational comparative study was carried out in children aged 1 year or older who were admitted in an intensive care unit. At 2 to 3 time points within 24 hours, a pain sedation assessment was carried out by the nurse in charge of the child with COMFORT scale, OPS and VAS. Correlation tests were used to compare the scores of each scale.

RESULTS

Nurses recorded 55 assessments in 20 children. Correlation studies showed a poor correlation between OPS, VAS and the COMFORT scale (Spearman's r=0.54 and 0.53 respectively) and a strong correlation between the COMFORT scale and the COMFORT "behaviour" scale (Spearman's r=0.96). The COMFORT behaviour scale was the most frequently fully completed scale.

CONCLUSION

Among the 3 scales compared to the COMFORT scale in this study, the COMFORT "behaviour" scale was the only one to show a strong correlation and it also seemed to be the easiest to use.

Analgesia and anesthesia for neonates: Study design and ethical issues

OBJECTIVE

The purpose of this article is to summarize the clinical, methodologic, and ethical considerations for researchers interested in designing future trials in neonatal analgesia and anesthesia, hopefully stimulating additional research in this field.

METHODS

The MEDLINE, PubMed, EMBASE, and Cochrane register databases were searched using subject headings related to infant, newborn, neonate, analgesia, anesthesia, ethics, and study design. Cross-references and personal files were searched manually. Studies reporting original data or review articles related to these topics were assessed and critically evaluated by experts for each topical area. Data on population demographics, study characteristics, and cognitive and behavioral outcomes were abstracted and synthesized in a systematic manner and refined by group members. Data synthesis and results were reviewed by a panel of independent experts and presented to a wider audience including clinicians, scientists, regulatory personnel, and industry representatives at the Newborn Drug Development Initiative workshop. Recommendations were revised after extensive discussions at the workshop and between committee members.

RESULTS

Designing clinical trials to investigate novel or currently available approaches for analgesia and anesthesia in neonates requires consideration of salient study designs and ethical issues. Conditions requiring treatment include pain/stress resulting from invasive procedures, surgical operations, inflammatory conditions, and routine neonatal intensive care. Study design considerations must define the inclusion and exclusion criteria, a rationale for stratification, the confounding effects of comorbid conditions, and other clinical factors. Significant ethical issues include the constraints of studying neonates, obtaining informed consent, making risk-benefit assessments, defining compensation or rewards for participation, safety considerations, the use of placebo controls, and the variability among institutional review boards in interpreting federal guidelines on human research. For optimal study design, investigators must formulate well-defined study questions, choose appropriate trial designs, estimate drug efficacy, calculate sample size, determine the duration of the studies, identify pharmacokinetic and pharmacodynamic parameters, and avoid drug-drug interactions. Specific outcome measures may include scoring on pain assessment scales, various biomarkers and their patterns of response, process outcomes (eg, length of stay, time to extubation), intermediate or long-term outcomes, and safety parameters.

CONCLUSIONS

Much more research is needed in this field to formulate a scientifically sound, evidence-based, and clinically useful framework for management of anesthesia and analgesia in neonates. Newer study designs and additional ethical dilemmas may be defined with accumulating data in this field.

Does neonatal surgery lead to increased pain sensitivity in later childhood?

Does pain or tissue damage in early life lead to hyperalgesia persisting into childhood? We performed a cross-sectional study in 164 infants to investigate whether major surgery within the first 3 months of life increases pain sensitivity to subsequent surgery and to elucidate whether subsequent surgery in the same dermatome or in a different dermatome leads to differences in pain sensitivity. All infants received standard intraoperative and postoperative pain management, with rescue analgesia guided by a treatment algorithm. Differences in pain sensitivity during surgery were assessed by the intraoperative fentanyl intake and by (nor)epinephrine plasma concentrations. Differences in postoperative pain sensitivity were assessed by the observational pain measures COMFORT and VAS, and by morphine intake and (nor)epinephrine plasma concentrations. Infants previously operated upon in the same dermatome needed more intraoperative fentanyl, had higher COMFORT and VAS scores, had greater (nor)epinephrine plasma concentrations, and needed also more morphine than did infants with no prior surgery. In contrast, infants who previously underwent surgery in another dermatome had only significant higher postoperative analgesic requirements and norepinephrine plasma concentrations in comparison with infants with no prior surgery. These preliminary differences may indicate the occurrence of spinal and supraspinal changes following neonatal surgery. We conclude that the long-term consequences of surgery in early infancy are greater in areas of prior tissue damage and that these effects may portend limited clinical but important neurobiological differences.