Enteral methadone to expedite fentanyl discontinuation and prevent opioid abstinence syndrome in the PICU

Use of Methadone Versus Oxycodone to Facilitate Weaning of Parenteral Opioids in Critically Ill Adult Patients

BACKGROUND

No previous literature has compared methadone with oxycodone for intravenous (IV) opioid weaning.

OBJECTIVE

To determine if a weaning strategy using enteral methadone or oxycodone results in faster time to IV opioid discontinuation.

METHODS

This was a single-center, retrospective, cohort medical record review of mechanically ventilated adults in an intensive care unit (ICU) who received a continuous IV infusion of fentanyl or hydromorphone for ≥72 hours and an enteral weaning strategy using either methadone or oxycodone from January 1, 2020, through December 31, 2021. Differences between groups were controlled for using Cox proportional hazards models. The primary outcome was time to continuous IV opioid discontinuation from the initiation of enteral opioids. Secondary outcomes included the primary endpoint stratified for COVID-19, duration of mechanical ventilation, ICU and hospital length of stay, and safety measures.

RESULTS

Ninety-three patients were included, with 36 (38.7%) patients receiving methadone and 57 (61.3%) receiving oxycodone. Patients weaned using methadone received IV opioids significantly longer before the start of weaning (P = 0.04). However, those on methadone had a significantly faster time to discontinuation of IV opioids than those on oxycodone, mean (standard deviation) 104.7 (79.4) versus 158.3 hours (171.2), P = 0.04, and, at any time, were 1.89 times as likely to be weaned from IV opioids (hazard ratio, HR 1.89, 95% confidence interval, CI 1.16-3.07, P = 0.01).

CONCLUSION AND RELEVANCE

This was the first study showing enteral methadone was associated with a shorter duration of IV opioids without differences in secondary outcomes compared with oxycodone. Prospective research is necessary to confirm this finding.

2022 Society of Critical Care Medicine Clinical Practice Guidelines on Prevention and Management of Pain, Agitation, Neuromuscular Blockade, and Delirium in Critically Ill Pediatric Patients With Consideration of the ICU Environment and Early Mobility

RATIONALE

A guideline that both evaluates current practice and provides recommendations to address sedation, pain, and delirium management with regard for neuromuscular blockade and withdrawal is not currently available.

OBJECTIVE

To develop comprehensive clinical practice guidelines for critically ill infants and children, with specific attention to seven domains of care including pain, sedation/agitation, iatrogenic withdrawal, neuromuscular blockade, delirium, PICU environment, and early mobility.

DESIGN

The Society of Critical Care Medicine Pediatric Pain, Agitation, Neuromuscular Blockade, and Delirium in critically ill pediatric patients with consideration of the PICU Environment and Early Mobility Guideline Taskforce was comprised of 29 national experts who collaborated from 2009 to 2021 via teleconference and/or e-mail at least monthly for planning, literature review, and guideline development, revision, and approval. The full taskforce gathered annually in-person during the Society of Critical Care Medicine Congress for progress reports and further strategizing with the final face-to-face meeting occurring in February 2020. Throughout this process, the Society of Critical Care Medicine standard operating procedures Manual for Guidelines development was adhered to.

METHODS

Taskforce content experts separated into subgroups addressing pain/analgesia, sedation, tolerance/iatrogenic withdrawal, neuromuscular blockade, delirium, PICU environment (family presence and sleep hygiene), and early mobility. Subgroups created descriptive and actionable Population, Intervention, Comparison, and Outcome questions. An experienced medical information specialist developed search strategies to identify relevant literature between January 1990 and January 2020. Subgroups reviewed literature, determined quality of evidence, and formulated recommendations classified as "strong" with "we recommend" or "conditional" with "we suggest." Good practice statements were used when indirect evidence supported benefit with no or minimal risk. Evidence gaps were noted. Initial recommendations were reviewed by each subgroup and revised as deemed necessary prior to being disseminated for voting by the full taskforce. Individuals who had an overt or potential conflict of interest abstained from relevant votes. Expert opinion alone was not used in substitution for a lack of evidence.

RESULTS

The Pediatric Pain, Agitation, Neuromuscular Blockade, and Delirium in critically ill pediatric patients with consideration of the PICU Environment and Early Mobility taskforce issued 44 recommendations (14 strong and 30 conditional) and five good practice statements.

CONCLUSIONS

The current guidelines represent a comprehensive list of practical clinical recommendations for the assessment, prevention, and management of key aspects for the comprehensive critical care of infants and children. Main areas of focus included 1) need for the routine monitoring of pain, agitation, withdrawal, and delirium using validated tools, 2) enhanced use of protocolized sedation and analgesia, and 3) recognition of the importance of nonpharmacologic interventions for enhancing patient comfort and comprehensive care provision.

Current State of Analgesia and Sedation in the Pediatric Intensive Care Unit

Critically ill pediatric patients often require complex medical procedures as well as invasive testing and monitoring which tend to be painful and anxiety-provoking, necessitating the provision of analgesia and sedation to reduce stress response. Achieving the optimal combination of adequate analgesia and appropriate sedation can be quite challenging in a patient population with a wide spectrum of ages, sizes, and developmental stages. The added complexities of critical illness in the pediatric population such as evolving pathophysiology, impaired organ function, as well as altered pharmacodynamics and pharmacokinetics must be considered. Undersedation leaves patients at risk of physical and psychological stress which may have significant long term consequences. Oversedation, on the other hand, leaves the patient at risk of needing prolonged respiratory, specifically mechanical ventilator, support, prolonged ICU stay and hospital admission, and higher risk of untoward effects of analgosedative agents. Both undersedation and oversedation put critically ill pediatric patients at high risk of developing PICU-acquired complications (PACs) like delirium, withdrawal syndrome, neuromuscular atrophy and weakness, post-traumatic stress disorder, and poor rehabilitation. Optimal analgesia and sedation is dependent on continuous patient assessment with appropriately validated tools that help guide the titration of analgosedative agents to effect. Bundled interventions that emphasize minimizing benzodiazepines, screening for delirium frequently, avoiding physical and chemical restraints thereby allowing for greater mobility, and promoting adequate and proper sleep will disrupt the PICU culture of immobility and reduce the incidence of PACs.

Methadone: applications in pediatric anesthesiology and critical care medicine

Like morphine, methadone is a pure agonist at the µ opioid receptor. However, in distinction to morphine which has an elimination half-life of 2-3 h, methadone has an elimination half-life of 24-36 h. In addition to its effects at the µ opioid receptor, methadone is an antagonist at the N-methyl-D-aspartate (NMDA) receptor and also inhibits the reuptake of the neurotransmitters, serotonin and norepinephrine, in the central nervous system. Given its long half-life and high oral bioavailability, methadone has had a primary role in the outpatient treatment of patients with a history of opioid abuse or addiction. However, its unique pharmacology and cellular effects make it a valuable agent in the treatment of both acute and chronic pain of various etiologies. The following manuscript reviews the pharmacologic properties of methadone and discusses its clinical applications in the practice of pediatric anesthesiology and pediatric critical care medicine.

Exposure-Based Methadone and Lorazepam Weaning Protocol Reduces Wean Length in Children

OBJECTIVE

Determine if a standardized methadone and lorazepam weaning protocol that is based on dose and duration of exposure can reduce the length of opioid and benzodiazepine weaning and shorten hospital stay.

METHODS

Retrospective cohort study performed in a 24-bed medical/surgical PICU. A total of 177 patients on opioid and/or benzodiazepine infusions for >3 days were included; 75 patients pre protocol (June 2012- June 2013) were compared with 102 patients post implementation of a standardized weaning protocol of methadone and lorazepam (March 2014-March 2015). The recommended wean was based on duration of infusions of >3 days up to 5 days (no wean), 5 to 13 days (short wean), and ≥14 days (long wean).

RESULTS

Median number of days on methadone for patients on opioid infusions for 5 to 13 days was reduced from 8.5 to 5.7 days (p = 0.001; n = 45 [pre], n = 68 [post]) and for patients on opioid infusions for ≥14 days, from 29.7 to 11.5 days (p = 0.003; n = 9 [pre], n = 9 [post]) after protocol implementation. The median number of days on lorazepam for patients on benzodiazepine infusions for 5 to 13 days was reduced from 8.1 to 5.2 days (p = 0.020; n = 43 [pre], n = 55 [post]) and for patients on benzodiazepine infusions for ≥14 days, from 27.4 to 9.3 days (p = 0.011; n = 9 [pre], n = 8 [post]). There was no difference in methadone or lorazepam wean length for patients on 3 to 5 days of infusions. There was no difference in adverse events or hospital length of stay.

CONCLUSIONS

A methadone and lorazepam weaning protocol based on patient's exposure to opioids and benzodiazepines (dose and duration) reduces weaning length.

Pain management in trauma patients affected by the opioid epidemic: A narrative review

Acute and chronic pain in trauma patients remains a challenging entity, particularly in the setting of the escalating opioid epidemic. It has been reported that chronic opioid use increases the likelihood of hospital admissions as a result of traumatic injuries. Furthermore, patients admitted with traumatic injuries have a greater than average risk of developing opioid use disorder after discharge. Practitioners providing care to these patients will encounter the issue of balancing analgesic goals and acute opioid withdrawal with the challenge of reducing postdischarge persistent opioid use. Additionally, the practitioner is faced with the worrisome prospect that inadequate treatment of acute pain may lead to the development of chronic pain and overtreatment may result in opioid dependence. It is therefore imperative to understand and execute alternative nonopioid strategies to maximize the benefits and reduce the risks of analgesic regimens in this patient population. This narrative review will analyze the current literature on pain management in trauma patients and highlight the application of the multimodal approach in potentially reducing the risks of both short- and long-term opioid use. LEVEL OF EVIDENCE: Narrative review, moderate to High.

Assessment and treatment of the withdrawal syndrome in paediatric intensive care units: Systematic review

BACKGROUND

Sedoanalgesia secondary iatrogenic withdrawal syndrome (IWS) in paediatric intensive units is frequent and its assessment is complex. Therapies are heterogeneous, and there is currently no gold standard method for diagnosis. In addition, the assessment scales validated in children are scarce. This paper aims to identify and describe both the paediatric diagnostic and assessment tools for the IWS and the treatments for the IWS in critically ill paediatric patients.

METHODS

A systematic review was conducted according to the PRISMA guidelines. This review included descriptive and observational studies published since 2000 that analyzed paediatric scales for the evaluation of the iatrogenic withdrawal syndrome and its treatments. The eligibility criteria included neonates, newborns, infants, pre-schoolers, and adolescents, up to age 18, who were admitted to the paediatric intensive care units with continuous infusion of hypnotics and/or opioid analgesics, and who presented signs or symptoms of deprivation related to withdrawal and prolonged infusion of sedoanalgesia.

RESULTS

Three assessment scales were identified: Withdrawal Assessment Tool-1, Sophia Observation Withdrawal Symptoms, and Opioid and Benzodiazepine Withdrawal Score. Dexmedetomidine, methadone and clonidine were revealed as options for the treatment and prevention of the iatrogenic withdrawal syndrome. Finally, the use of phenobarbital suppressed symptoms of deprivation that are resistant to other drugs.

CONCLUSIONS

The reviewed scales facilitate the assessment of the iatrogenic withdrawal syndrome and have a high diagnostic quality. However, its clinical use is very rare. The treatments identified in this review prevent and effectively treat this syndrome. The use of validated iatrogenic withdrawal syndrome assessment scales in paediatrics clinical practice facilitates assessment, have a high diagnostic quality, and should be encouraged, also ensuring nurses' training in their usage.

Opioid tapering and weaning protocols in pediatric critical care units: a systematic review

OBJECTIVE

Opioid abstinence syndrome is common in the pediatric intensive care environment because sedation is often needed during the children's treatment. There is no specific guideline regarding the management of these patients; and lately, methadone is an important drug for the prevention of abstinence symptoms during the weaning of opioids. This study gathers the available research to establish the initial dose of methadone, the rate of taper and tools to recognize this syndrome and act promptly.

METHODS

A systematic review was made from data of four different databases. Forty-nine articles of observational and experimental studies were selected based on the inclusion criteria (critical pediatric patients in acute use of opioids) and exclusion criteria (previous chronic use of opioids, other medications). The data regarding specific themes were separated in sections: initial dose of methadone, use of protocols in clinical practice, abstinence scales and adjuvant drugs.

RESULTS

The articles showed a great heterogeneity of ways to calculate the initial dose of methadone. The pediatric intensive care units of the study had different weaning protocols, with a lower incidence of abstinence when a pre-defined sequence of tapering was used. The Withdrawal Assessment Tool - 1 was the most used scale for tapering the opioids, with good sensitivity and specificity for signs and symptoms.

CONCLUSION

There is still little evidence of other medications that can help prevent the abstinence syndrome of opioids. This study tries to promote a better practice during opioid weaning.

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.

Analgesic and sedative agents used in the intensive care unit: A review

Pain is a common experience for most patients in the intensive care unit (ICU). In the current study, the advantages and disadvantages of analgesic and sedative drugs used in the ICU are reviewed. An ideal sedative and analgesic agent should have features such as rapid onset of action, rapid recovery after discontinuation, predictability, minimal accumulation of the agent and metabolites in the body, and lack of toxicity. None of the sedative and analgesic agents have all of these desired characteristics; nevertheless, clinicians must be familiar with these classes of drugs to optimize pharmacotherapy and ensure as few side-effects as possible for ICU patients.

Shortened Taper Duration after Implementation of a Standardized Protocol for Iatrogenic Benzodiazepine and Opioid Withdrawal in Pediatric Patients: Results of a Cohort Study

Supplemental Digital Content is available in the text.

Introduction:

Methadone and lorazepam prescribing discrepancies for the use of iatrogenic withdrawal were observed among providers. A standardized pharmacist-managed methadone and lorazepam taper protocol was implemented at a pediatric tertiary care facility with the aim to reduce the length of taper for patients with iatrogenic withdrawal.

Methods:

A multidisciplinary team of nurses, pharmacists, and physicians reviewed the current literature, then developed and implemented a standardized withdrawal taper protocol. Outcomes were compared with a retrospective control group using past prescribing practices. The primary endpoint was the length of methadone and/or lorazepam taper. Secondary endpoints included evaluation for significant differences between the control and standardized protocol groups regarding additional breakthrough withdrawal medications, pediatric intensive care unit (PICU) and hospital length of stay. We also evaluated provider satisfaction with the protocol.

Results:

The standardized protocol group included 25 patients who received methadone and/or lorazepam taper. A retrospective control group contained 24 patients. Median methadone taper length before protocol implementation was 9.5 days with an interquartile range (IQR) of 5.5–14.5 days; after protocol implementation, it was 6.0 (IQR, 3.0–9.0) days (P = 0.0145). Median lorazepam taper length before protocol implementation was 13.0 (IQR, 8.0–18.0) days; after protocol implementation, it was 6.0 (4.0–7.0) days (P = 0.0006). A statistical difference between PICU length of stay, hospital length of stay, or the number of additional medications for breakthrough withdrawal was not found.

Conclusions:

The use of a standardized withdrawal protocol resulted in shorter taper duration for both the methadone and lorazepam groups. There was no difference in PICU or hospital length of stay.

Opioid and Benzodiazepine Weaning in Pediatric Patients: Review of Current Literature

Pediatric opioid and benzodiazepine withdrawal are avoidable complications of pain and sedation management that is well described in the literature. To prevent withdrawal from occurring, practitioners regularly use a steady decrease of pain and sedation medications, also known as a weaning or tapering schedule. The weaning schedule is highly variable based on clinician preference and is usually dependent on the clinician. The purposes of this review are to evaluate the current literature on the process of opioid and benzodiazepine weaning in pediatric patients and to assess the various standardized protocols used to decrease withdrawal occurrences. We conducted a search of the PubMed, MEDLINE, Cochrane Library, Cumulative Index of Nursing and Allied Health (CINAHL), Academic Search Premier, and PsycInfo databases. Studies were included if they described a wean or taper in pediatric patients aged 18 years or younger. Studies describing neonatal abstinence syndrome were excluded from the review. A total of 97 studies published between 2000 and 2014 were retrieved; of those, 15 studies met the inclusion criteria. Studies were evaluated for selection of withdrawal assessment tool, wean protocol summary, preferred weaning agents, benzodiazepine withdrawal, and wean-at-home regimen. The most common opioid-weaning protocol approaches described a 10-20% dose decrease per day. Benzodiazepine weaning was not regularly standardized or described. The use of a standardized opioid-weaning protocol reduced withdrawal rates compared with nonstandardized weaning plans. Benzodiazepine weaning was inconsistently evaluated and may have affected study outcomes. Identified areas of improvement include the use of newer withdrawal assessment tools validated in the older pediatric population and standardized withdrawal assessment and reporting.

Differentiating Delirium From Sedative/Hypnotic-Related Iatrogenic Withdrawal Syndrome: Lack of Specificity in Pediatric Critical Care Assessment Tools

OBJECTIVES

To identify available assessment tools for sedative/hypnotic iatrogenic withdrawal syndrome and delirium in PICU patients, the evidence supporting their use, and describe areas of overlap between the components of these tools and the symptoms of anticholinergic burden in children.

DATA SOURCES

Studies were identified using PubMed and EMBASE from the earliest available date until July 3, 2016, using a combination of MeSH terms "delirium," "substance withdrawal syndrome," and key words "opioids," "benzodiazepines," "critical illness," "ICU," and "intensive care." Review article references were also searched.

STUDY SELECTION

Human studies reporting assessment of delirium or iatrogenic withdrawal syndrome in children 0-18 years undergoing critical care. Non-English language, exclusively adult, and neonatal intensive care studies were excluded.

DATA EXTRACTION

References cataloged by study type, population, and screening process.

DATA SYNTHESIS

Iatrogenic withdrawal syndrome and delirium are both prevalent in the PICU population. Commonly used scales for delirium and iatrogenic withdrawal syndrome assess signs and symptoms in the motor, behavior, and state domains, and exhibit considerable overlap. In addition, signs and symptoms of an anticholinergic toxidrome (a risk associated with some common PICU medications) overlap with components of these scales, specifically in motor, cardiovascular, and psychiatric domains.

CONCLUSIONS

Although important studies have demonstrated apparent high prevalence of iatrogenic withdrawal syndrome and delirium in the PICU population, the overlap in these scoring systems presents potential difficulty in distinguishing syndromes, both clinically and for research purposes.

Conversion from prolonged intravenous fentanyl infusion to enteral methadone in critically ill children

AIM

To describe our institutional experience with conversion from intravenous (IV) fentanyl infusion directly to enteral methadone and occurrence of withdrawal in critically ill mechanically ventilated children exposed to prolonged sedation and analgesia.

METHODS

With Institutional Review Board approval, we retrospectively studied consecutively admitted invasively mechanically ventilated children (0-18 years) sedated with IV fentanyl infusion > 5 d and subsequently converted directly to enteral methadone. Data were obtained on subject demographics, illness severity, daily IV fentanyl and enteral methadone dosing, time to complete conversion, withdrawal scores (WAT-1), pain scores, and need for rescue opioids. Patients were classified as rapid conversion group (RCG) if completely converted ≤ 48 h and slow conversion group (SCG) if completely converted in > 48 h. Primary outcome was difference in WAT-1 scores at 7 d. Secondary outcomes included differences in overall pain scores, and differences in daily rescue opioids.

RESULTS

Compared to SCG (n = 21), RCG (n = 21) had lower median WAT-1 scores at 7 d (2.5 vs 5, P = 0.027). Additionally, RCG had lower overall median pain scores (3 vs 6, P = 0.007), and required less median daily rescue opioids (3 vs 12, P = 0.003) than SCG. The starting daily median methadone dose was 2.3 times the daily median fentanyl dose in the RCG, compared to 1.1 times in the SCG (P = 0.049).

CONCLUSION

We observed wide variation in conversion from IV fentanyl infusion directly to enteral methadone and variability in withdrawal in critically ill mechanically ventilated children exposed to prolonged sedation. In those children who converted successfully from IV fentanyl infusion to enteral methadone within a period of 48 h, a methadone:fentanyl dose conversion ratio of approximately 2.5:1 was associated with less withdrawal and reduced need for rescue opioids.

The use of methadone to facilitate opioid weaning in pediatric critical care patients: a systematic review of the literature and meta-analysis

BACKGROUND

Continuous opioid infusion therapy is commonly utilized in the pediatric intensive care setting to treat pain and facilitate tolerance of invasive therapies. Transitioning to methadone is one common strategy for weaning from continuous opioid infusions, but in practice this transition can be challenging, and many children still experience iatrogenic withdrawal.

AIM

We reviewed the literature to evaluate the best available evidence to guide methadone therapy in this setting, and to summarize associated adverse events.

METHODS

We included all studies of methadone used to facilitate weaning from continuous opioid infusions in pediatric critical care patients, including medical, cardiac, and surgical patients, excluding case reports and studies treating neonatal abstinence syndrome, or acute or chronic pain. Medline, Embase, and CINAHL databases from inception to May 2015 were queried; references of included works and conference proceedings were also reviewed. Two authors independently extracted data from each study. Meta-analysis with fixed- and random-effects models was used to pool results of studies when applicable.

RESULTS

Twelve studies involving 459 patients met criteria for inclusion. A wide variety of methadone dosing and taper strategies were reported. Mean inpatient methadone taper times varied widely, from 4.3 to 26.2 days. Excessive sedation was the most frequently reported adverse event, occurring in up to 16% of patients. Withdrawal occurred in 27% of patients among studies reporting this outcome. In three of three studies in which a new methadone protocol was introduced, a decreased proportion of patients experienced withdrawal (standardized mean difference, SMD = -0.60, 95% CI = -0.998 to -0.195, P = 0.004).

CONCLUSION

We did not identify sufficient evidence to recommend any particular methadone weaning strategy, or to recommend methadone over other medications or prescribed infusion weaning, for successful weaning of continuous opioid infusions in the pediatric intensive care setting.

Withdrawal Assessment Tool-1 Monitoring in PICU: A Multicenter Study on Iatrogenic Withdrawal Syndrome

OBJECTIVES

Withdrawal syndrome is an adverse reaction of analgesic and sedative therapy, with a reported occurrence rate between 17% and 57% in critically ill children. Although some factors related to the development of withdrawal syndrome have been identified, there is weak evidence for the effectiveness of preventive and therapeutic strategies. The main aim of this study was to evaluate the frequency of withdrawal syndrome in Italian PICUs, using a validated instrument. We also analyzed differences in patient characteristics, analgesic and sedative treatment, and patients' outcome between patients with and without withdrawal syndrome.

DESIGN

Observational multicenter prospective study.

SETTING

Eight Italian PICUs belonging to the national PICU network Italian PICU network.

PATIENTS

One hundred thirteen patients, less than 18 years old, mechanically ventilated and treated with analgesic and sedative therapy for five or more days. They were admitted in PICU from November 2012 to May 2014.

INTERVENTIONS

Symptoms of withdrawal syndrome were monitored with Withdrawal Assessment Tool-1 scale.

MEASUREMENTS AND MAIN RESULTS

The occurrence rate of withdrawal syndrome was 64.6%. The following variables were significantly different between the patients who developed withdrawal syndrome and those who did not: type, duration, and cumulative dose of analgesic therapy; duration and cumulative dose of sedative therapy; clinical team judgment about analgesia and sedation's difficulty; and duration of analgesic weaning, mechanical ventilation, and PICU stay. Multivariate logistic regression analysis revealed that patients receiving morphine as their primary analgesic were 83% less likely to develop withdrawal syndrome than those receiving fentanyl or remifentanil.

CONCLUSIONS

Withdrawal syndrome was frequent in PICU patients, and patients with withdrawal syndrome had prolonged hospital treatment. We suggest adopting the lowest effective dose of analgesic and sedative drugs and frequent reevaluation of the need for continued use. Further studies are necessary to define common preventive and therapeutic strategies.

Importance of the use of protocols for the management of analgesia and sedation in pediatric intensive care unit

Summary Introduction: Analgesia and sedation are essential elements in patient care in the intensive care unit (ICU), in order to promote the control of pain, anxiety and agitation, prevent the loss of devices, accidental extubation, and improve the synchrony of the patient with mechanical ventilation. However, excess of these medications leads to rise in morbidity and mortality. The ideal management will depend on the adoption of clinical and pharmacological measures, guided by scales and protocols. Objective: Literature review on the main aspects of analgesia and sedation, abstinence syndrome, and delirium in the pediatric intensive care unit, in order to show the importance of the use of protocols on the management of critically ill patients. Method: Articles published in the past 16 years on PubMed, Lilacs, and the Cochrane Library, with the terms analgesia, sedation, abstinence syndrome, mild sedation, daily interruption, and intensive care unit. Results: Seventy-six articles considered relevant were selected to describe the importance of using a protocol of sedation and analgesia. They recommended mild sedation and the use of assessment scales, daily interruptions, and spontaneous breathing test. These measures shorten the time of mechanical ventilation, as well as length of hospital stay, and help to control abstinence and delirium, without increasing the risk of morbidity and morbidity. Conclusion: Despite the lack of controlled and randomized clinical trials in the pediatric setting, the use of protocols, optimizing mild sedation, leads to decreased morbidity.

Caregiver Perception, Self-efficacy, and Knowledge of Methadone Tapers for Children With Iatrogenic Opioid Abstinence Syndrome

Background: There are no definitive guidelines regarding the management of iatrogenic opioid abstinence syndrome (IOAS), but methadone tapers are one common approach. Methadone tapers can be complex for caregivers to manage, and there is a paucity of data about caregiver experiences administering medication tapers postdischarge. Objective: The primary objective was to describe caregiver perception, self-efficacy, and knowledge of administering methadone tapers. Secondary objectives included an assessment of the change in self-efficacy and knowledge of methadone and IOAS before and after discharge as well as clinical outcomes occurring postdischarge. Methods: This was an exploratory, descriptive, institutional review board-approved study surveying caregivers of children receiving methadone tapers for IOAS. Caregivers were included if they had a child ≤12 years of age discharged to home on a methadone taper. The study consisted of 2 phases: a questionnaire and observation/counseling session predischarge and a telephone interview after taper completion. Univariate descriptive statistics were utilized for data analysis. Results: Phase 1 of the study was completed by 12 caregivers, and only 5 completed phase 2. The majority of caregivers were completely confident predischarge (83.3%) and postdischarge (80%) in administering methadone as prescribed. However, some caregivers were confused about the purpose of the taper and experienced difficulty in measuring oral solutions. Conclusions: Despite high self-efficacy, caregivers experienced difficulties in understanding taper management and during the observation session. The results of this study suggest presenting information to caregivers utilizing minimal medical jargon, conducting a counseling/observation session predischarge, and utilizing the teach-back method with caregivers to assess for understanding.

Impact of a Standardized Treatment Guideline for Pediatric Iatrogenic Opioid Dependence: A Quality Improvement Initiative

OBJECTIVES

To determine whether utilization of a hospital-based clinical practice guideline for the care of pediatric iatrogenic opioid dependence (IOD) would promote a decrease in opioid exposure and improve management of opioid abstinence syndrome (AS).

METHODS

This study is a retrospective chart review of critically ill patients from a tertiary care children's hospital. Inclusion criteria included mechanically ventilated patients up to 18 years of age who received continuous opioid infusions for at least 7 days and any length of methadone administration. Data on IOD patients from January 2005 to June 2010 was divided into 3 periods: baseline, phase 1, and phase 2. Primary outcome was decrease in opioid exposure, measured by methadone duration of use and any additional opioid bolus doses used in AS management. Documentation of additional opioid bolus doses was regarded as a surrogate measure of AS. Secondary outcomes included total cumulative fentanyl dose, continuous fentanyl infusion duration of use, and hospital and pediatric intensive care unit length of stay.

RESULTS

There was a significant decrease in methadone duration of use in IOD patients from 15.3 ± 8.7 days at baseline to 9.5 ± 3.7 days during phase 1 (p = 0.002), to 8.1 ± 3.7 days on phase 2 (reduction not significant, p = 0.106) of this evaluation. Additional opioid bolus doses were significantly lower from baseline to phase 1 (5.5 ± 5.1 vs. 1.8 ± 2.3, p = 0.001) and from phase 1 to phase 2 (1.8 ± 2.3 vs. 0.2 ± 1.5, p = 0.003). For the remaining outcomes, differences were not observed among the evaluation periods, except for the total cumulative fentanyl dose, which was reduced from 2.8 ± 3.7 mg/kg at baseline to 1 ± 1 mg/kg only during phase 1 (p = 0.017).

CONCLUSIONS

Introduction of a standardized, hospital-based clinical practice guideline for children with IOD reduced the length of exposure to opioids and improved opioid AS management.

Risk factors associated with iatrogenic opioid and benzodiazepine withdrawal in critically ill pediatric patients: a systematic review and conceptual model

OBJECTIVES

Analgesia and sedation are common therapies in pediatric critical care, and rapid titration of these medications is associated with iatrogenic withdrawal syndrome. We performed a systematic review of the literature to identify all common and salient risk factors associated with iatrogenic withdrawal syndrome and build a conceptual model of iatrogenic withdrawal syndrome risk in critically ill pediatric patients.

DATA SOURCES

Multiple databases, including PubMed/Medline, EMBASE, CINAHL, and the Cochrane Central Registry of Clinical Trials, were searched using relevant terms from January 1, 1980, to August 1, 2014.

STUDY SELECTION

Articles were included if they were published in English and discussed iatrogenic withdrawal syndrome following either opioid or benzodiazepine therapy in children in acute or intensive care settings. Articles were excluded if subjects were neonates born to opioid- or benzodiazepine-dependent mothers, children diagnosed as substance abusers, or subjects with cancer-related pain; if data about opioid or benzodiazepine treatment were not specified; or if primary data were not reported.

DATA EXTRACTION

In total, 1,395 articles were evaluated, 33 of which met the inclusion criteria. To facilitate analysis, all opioid and/or benzodiazepine doses were converted to morphine or midazolam equivalents, respectively. A table of evidence was developed for qualitative analysis of common themes, providing a framework for the construction of a conceptual model. The strongest risk factors associated with iatrogenic withdrawal syndrome include duration of therapy and cumulative dose. Additionally, evidence exists linking patient, process, and system factors in the development of iatrogenic withdrawal syndrome.

FINDINGS

Most articles were prospective observational or interventional studies.

CONCLUSIONS

Given the state of existing evidence, well-designed prospective studies are required to better characterize iatrogenic withdrawal syndrome in critically ill pediatric patients. This review provides data to support the construction of a conceptual model of iatrogenic withdrawal syndrome risk that, if supported, could be useful in guiding future research.

Development and implementation of a pharmacist-managed, neonatal and pediatric, opioid-weaning protocol

OBJECTIVES

To compare the length of wean and abstinence severity in neonatal and pediatric patients with neonatal abstinence syndrome or iatrogenic opioid dependence treated with a pharmacist-managed, methadone-based protocol compared with physician-managed patients treated with either methadone or dilute tincture of opium (DTO).

METHODS

This was a prospective, single-centered, interventional evaluation of 54 pharmacist-managed patients versus 53 retrospective, physician-managed patients. Wean duration and severity of neonatal abstinence syndrome were compared between groups using the Student t test.

RESULTS

Significantly shorter wean duration in in utero-exposed pharmacist-managed patients compared with patients on physician-managed DTO (11.7 days vs 24.2 days, p < 0.001), but not compared with patients on physician-managed methadone (11.7 days vs 47 days, p = 0.101). No statistically significant difference was seen in wean duration in iatrogenic-exposed pharmacist-managed patients compared with patients on either physician-managed DTO or methadone (8.69 days vs 14 days, p = 0.096) and (8.69 days vs 9.82 days, p = 0.34), respectively. There were significantly fewer abstinence scores >12 in pharmacist-managed patients versus physician-managed DTO, but not physician-managed methadone (2.05 vs 17.3, p = 0.008 and 2.05 vs 74.3, p = 0.119, respectively). Significantly fewer abstinence scores ≥8 × 3 consecutively were seen in pharmacist-managed patients compared with patients on either physician-managed DTO or methadone (2.89 vs 11.9, p = 0.01 and 2.89 vs 24, p < 0.001, respectively).

CONCLUSIONS

Use of a pharmacist-managed, methadone-based weaning protocol standardizes patient care and has the potential to decrease abstinence severity and shorten duration of wean versus physician-managed patients exposed to opioids in utero. Additionally, a methadone wean of 10% to 20% per day was well tolerated in both neonatal and pediatric patients.

Evaluation of a pharmacist-managed methadone taper*

OBJECTIVES

To evaluate the efficacy of a pharmacist-managed methadone taper as compared to previous prescribing practices.

DESIGN

Retrospective chart review with comparison to historical controls.

SETTING

Ninety-six-bed pediatric quaternary care facility with the majority of the patients in a 24-bed ICU.

PATIENTS

Thirty-two patients, 1 month to 16 years old, weaned off opioids using methadone prior to protocol initiation were compared with 20 patients, 1 month to 15 years old, weaned per the pharmacist-managed methadone taper protocol.

INTERVENTIONS

Implementation of a pharmacist-managed methadone tapering protocol.

MEASUREMENTS AND MAIN RESULTS

Patient age, gender, weight, and risk of withdrawal were similar between the groups (p = not significant). The average taper length before pharmacist intervention was 24.7 days; after implementation it was 15 days (p = 0.0026). There was no statistical difference in the number of additional doses of opioid required or withdrawal scores between the populations. Opioid infusions were stopped, on average, 1.54 days sooner in the intervention group (p = 0.0039). A decrease in hospital length of stay was also seen in the intervention group (p = 0.023).

CONCLUSIONS

A pharmacist-managed protocolized methadone taper facilitates discontinuing methadone sooner, discontinuing additional opioid infusions sooner, and may impact on the length of hospital stay. The protocol developed at the University of Minnesota Amplatz Children's Hospital has demonstrated that it is an effective method to wean pediatric patients from opioids.

Defining sedation-related adverse events in the pediatric intensive care unit

BACKGROUND

Clinical trials exploring optimal sedation management in critically ill pediatric patients are urgently needed to improve both short- and long-term outcomes. Concise operational definitions that define and provide best-available estimates of sedation-related adverse events (AE) in the pediatric population are fundamental to this line of inquiry.

OBJECTIVES

To perform a multiphase systematic review of the literature to identify, define, and provide estimates of sedation-related AEs in the pediatric ICU setting for use in a multicenter clinical trial.

METHODS

In Phase One, we identified and operationally defined the AE. OVID-MEDLINE and CINAHL databases were searched from January 1998 to January 2012. Key terms included sedation, intensive and critical care. We limited our search to data-based clinical trials from neonatal to adult age. In Phase Two, we replicated the search strategy for all AEs and identified pediatric-specific AE rates.

RESULTS

We reviewed 20 articles identifying sedation-related adverse events and 64 articles on the pediatric-specific sedation-related AE. A total of eleven sedation-related AEs were identified, operationally defined and estimated pediatric event rates were derived. AEs included: inadequate sedation management, inadequate pain management, clinically significant iatrogenic withdrawal, unplanned endotracheal tube extubation, post-extubation stridor with chest-wall retractions at rest, extubation failure, unplanned removal of invasive tubes, ventilator-associated pneumonia, catheter-associated bloodstream infection, Stage II+ pressure ulcers and new tracheostomy.

CONCLUSIONS

Concise operational definitions that defined and provided best-available event rates of sedation-related AEs in the pediatric population are presented. Uniform reporting of adverse events will improve subject and patient safety.

External Validation of the Medication Taper Complexity Score for Methadone Tapers in Children With Opioid Abstinence Syndrome

Background: Methadone is commonly prescribed for children with opioid abstinence syndrome (OAS) as a taper schedule over several days to weeks. The Medication Taper Complexity Score (MTCS) was developed to evaluate outpatient methadone tapers. Objective: To further validate the MTCS and determine if it is a reliable tool for clinicians to use to assess the complexity of methadone tapers for OAS. Methods: An expert panel of pediatric clinical pharmacists was convened. Panel members were provided 9 methadone tapers (ie, “easy,” “medium,” and “difficult”) to determine construct and face validity of the MTCS. The primary objective was to further establish reliability and construct/face validity of the MTCS. The secondary objective was to assess the reliability of the MTCS within and between tapers. Instrument reliability was assessed using a Pearson correlation coefficient; with 0.8 as the minimum acceptable coefficient. Construct (divergent) validity was assessed via a repeated-measures ANOVA analysis (Bonferroni post hoc analyses) of the mean scores provided by panel members. Results: Six panel members were recruited from various geographical locations. Panel members had 18.3 ± 5.5 years of experience, with practice expertise in general pediatrics, hematology/oncology, and the pediatric and neonatal intensive care unit. The MTCS had a reliability coefficient of .9949. There was vivid discrimination between the easy, medium, and difficult tapers; P = .001. The panel recommended minor modifications to the MTCS. Conclusions: The MTCS was found to be a reliable and valid tool. Overall, the panel felt that the MTCS was easy to use and had potential applications in both practice and research.

Replacement of fentanyl infusion by enteral methadone decreases the weaning time from mechanical ventilation: a randomized controlled trial

INTRODUCTION

Patients undergoing mechanical ventilation (MV) are frequently administered prolonged and/or high doses of opioids which when removed can cause a withdrawal syndrome and difficulty in weaning from MV. We tested the hypothesis that the introduction of enteral methadone during weaning from sedation and analgesia in critically ill adult patients on MV would decrease the weaning time from MV.

METHODS

A double-blind randomized controlled trial was conducted in the adult intensive care units (ICUs) of four general hospitals in Brazil. The 75 patients, who met the criteria for weaning from MV and had been using fentanyl for more than five consecutive days, were randomized to the methadone (MG) or control group (CG). Within the first 24 hours after study enrollment, both groups received 80% of the original dose of fentanyl, the MG received enteral methadone and the CG received an enteral placebo. After the first 24 hours, the MG received an intravenous (IV) saline solution (placebo), while the CG received IV fentanyl. For both groups, the IV solution was reduced by 20% every 24 hours. The groups were compared by evaluating the MV weaning time and the duration of MV, as well as the ICU stay and the hospital stay.

RESULTS

Of the 75 patients randomized, seven were excluded and 68 were analyzed: 37 from the MG and 31 from the CG. There was a higher probability of early extubation in the MG, but the difference was not significant (hazard ratio: 1.52 (95% confidence interval (CI) 0.87 to 2.64; P = 0.11). The probability of successful weaning by the fifth day was significantly higher in the MG (hazard ratio: 2.64 (95% CI: 1.22 to 5.69; P < 0.02). Among the 54 patients who were successfully weaned (29 from the MG and 25 from the CG), the MV weaning time was significantly lower in the MG (hazard ratio: 2.06; 95% CI 1.17 to 3.63; P < 0.004).

CONCLUSIONS

The introduction of enteral methadone during weaning from sedation and analgesia in mechanically ventilated patients resulted in a decrease in the weaning time from MV.

Impact of enteral methadone on the ability to wean off continuously infused opioids in critically ill, mechanically ventilated adults: a case-control study

BACKGROUND

Continuously infused opioids are frequently used to optimize patient comfort in the intensive care unit (ICU). However, concerns about rebound pain and opioid withdrawal may delay efforts to discontinue this therapy.

OBJECTIVE

To measure the association between use of scheduled enteral methadone according to a protocol in mechanically ventilated, medical critically ill adults receiving prolonged continuously infused fentanyl and the time to discontinue continuously infused fentanyl therapy.

METHODS

This case-control study included 20 consecutive mechanically ventilated adults in a medical ICU, without a history of chronic opioid use, who received 72 or more hours of continuously infused fentanyl and were prescribed scheduled enteral methadone as part of a protocol medical ICU strategy to wean off continuously infused fentanyl. Patients were matched in a 1:2 fashion, by duration of mechanical ventilation, to 40 consecutive preprotocol medical ICU patients meeting the same criteria but who were never given methadone. Duration of continuously infused fentanyl was compared between the 2 groups by constructing Kaplan-Meier plots and estimating the likelihood that methadone use was associated with a decrease in continuously infused fentanyl requirements over time, using a Cox proportional hazards model.

RESULTS

The groups were well matched except the methadone patients were older (p = 0.04). Time (median [interquartile range]) to continuously infused fentanyl discontinuation was shorter in the methadone group (4.5 [3.9-5.8] vs 7.0 [4.9-11.5] days; p = 0.002). Continuously infused fentanyl was more likely to be discontinued 2 days after methadone was first initiated (hazard ratio 9.1; p = 0.0004). The proportion of patients who experienced 1 or more episodes of either QTc interval prolongation (p = 0.79) or unarousability (p = 0.47) was similar between the groups.

CONCLUSIONS

Enterally administered methadone is associated with earlier cessation of continuously infused fentanyl in mechanically ventilated adults without a history of opioid dependence admitted to a medical ICU. Prospective, controlled studies are needed to further evaluate the safety and efficacy of methadone as a strategy to wean off continuously infused fentanyl in different ICU populations.

Selection of the initial methadone regimen for the management of iatrogenic opioid abstinence syndrome in critically ill children

Iatrogenic opioid abstinence syndrome (IOAS) is a common complication in critically ill infants and children receiving prolonged exposure to continuous infusions of opioids. Although no guidelines are available regarding management of IOAS in children, several treatment options are available, including clonidine, morphine, and methadone. Methadone is commonly prescribed due to its long half-life and antagonism of the N-methyl-d-aspartate receptor. Different approaches, such as weight-based and formula-based methods, have been used to determine the initial methadone dosing regimen. Because of the vast differences in the recommended dosing regimen from these sources, we conducted a literature search to identify articles evaluating the initial methadone dosing regimen for prevention and/or treatment of IOAS in children. Specifically, we evaluated the reported frequency of withdrawal and oversedation after initiation of methadone treatment. Our literature search was limited to English-language articles in the MEDLINE (1950-March 2011), EMBASE (1988-March 2011), International Pharmaceutical Abstracts (1970-March 2011), and Cochrane Library (1996-March 2011) databases. Relevant abstracts and reference citations were also reviewed. A total of eight reports representing 183 patients were included in the analysis. There was wide discrepancy in the initial methadone dosing regimen. Approximately one-third of all patients experienced withdrawal after starting methadone, and there did not appear to be a difference between weight-based and formula-based regimens. Seven patients experienced oversedation; however, not all articles reported this complication. It appears that a standard approach to initial methadone dosing does not exist because withdrawal occurred despite the regimen started. Therefore, it seems best to begin with the lowest dose possible and titrate to the child's response to avoid complications such as oversedation. Routine monitoring should be performed in all patients to guide clinicians in the management of IOAS.

A pilot study assessing the frequency and complexity of methadone tapers for opioid abstinence syndrome in children discharged to home

BACKGROUND

Methadone is often prescribed as a taper schedule to prevent/treat opioid abstinence syndrome (OAS) or neonatal abstinence syndrome (NAS).

OBJECTIVE

The objective of this study was to determine the percentage of children discharged home on methadone tapers and to develop, assess, and implement an instrument for measuring the complexity of the methadone regimens.

METHODS

This study used a descriptive retrospective design to examine patients younger than 18 years from January 1, 2008, to December 31, 2008, administered methadone for prevention/treatment of OAS/NAS and discharged home on a methadone taper. Data collection included demographics and characteristics of methadone regimen. The primary objective was to determine the percentage of children discharged on methadone. Secondary objectives included characterization (ie, number of dosage and interval changes), duration, and complexity of the methadone taper. Descriptive statistics were performed using Stata v10 (StataCorp LP, College Station, TX). Complexity was evaluated using the medication taper complexity score (MTCS) between 4 raters. Reliability of the MTCS was established using interrater correlation analyses of the regimen complexity scores.

RESULTS

Thirty-three patients (41.8%) were discharged on methadone. The median (range) age was 0.42 (0-12) years, with most patients (75.8%) initiated on methadone for prevention of OAS. Thirty-one patients were included for further analysis of medication complexity. The median (range) duration of the home taper was 8 days (2-48), which included a median (range) of 4 (1-11) dose changes and at least 1 (0-2) change in the interval. MTCS ranged from 7 to 42, with the tool demonstrating 95% interrater reliability.

CONCLUSIONS

More than one-third of patients were discharged home on methadone. The median taper duration was 8 days and included a median of 5 adjustments in either the dose or interval. The MTCS demonstrated very good interrater reliability to measure wide variability in the complexity of individual tapers. Future studies should determine the construct validity of the MTCS and the applicability of this tool for further research and clinical application.

Methadone use in children and young adults at a cancer center: a retrospective study

OBJECTIVE

To augment the literature on methadone applications in pediatric oncology, the authors reviewed the use of methadone at a pediatric cancer center over a 5-year period.

DESIGN AND SETTING

Forty-one patients received methadone for inpatient or outpatient pain management. The authors retrospectively reviewed their demographic characteristics, diagnoses, type of pain (nociceptive, neuropathic, or mixed) and causes of pain, and the indications, dose regimens, adverse effects, and outcomes of methadone treatment.

RESULTS

There were four types of clinical uses for methadone in 41 patients (10 patients had two): nociceptive pain unresponsive to other opioids (17 patients, 33.3 percent), neuropathic pain (20 patients, 39.2 percent), facilitation of weaning from opioids (11 patients, 21.6 percent), and end-of-life pain management (3 patients, 5.9 percent). The mean age of the 24 males (58.5 percent) and 17 females (41.5 percent) at the start of treatment was 15.7 years (range, 0.6-23 years). The most common diagnoses were leukemia (n = 10, 24.4 percent), osteosarcoma (n = 7, 17.0 percent), and rhabdomyosarcoma (n = 5, 12.2 percent). The causes of pain were bone marrow transplant (n = 13, 31.7 percent), amputation (n = 6, 14.6 percent), chemotherapy (n = 5, 12.2 percent), tumor (n = 5, 12.2 percent), limb-sparing surgery (n = 4, 9.8 percent), and other (n = 8, 19.5 percent). Efficacy was assessed at the end (or after 6 months) of methadone treatment. For many patients (43.1 percent), methadone showed efficacy in achieving the purpose for which it was prescribed, including reduction of nociceptive or neuropathic pain and prevention of opioid withdrawal. Sedation was the most common side effect (24.4 percent).

CONCLUSIONS

Methadone was effective for pediatric patients with neuropathic pain or nociceptive pain unresponsive to other opioids, and it effectively prevented opioid withdrawal.

Use of methadone for prevention of opioid withdrawal in critically ill children

BACKGROUND

Opioids are commonly administered to critically ill children for analgesia and sedation, but many patients experience opioid withdrawal upon discontinuation. The authors' institution developed a protocol for using methadone to prevent opioid withdrawal in children who have received morphine by continuous IV infusion for 5 days or longer in the pediatric intensive care unit (PICU).

OBJECTIVES

The primary objectives were to determine if opioids were tapered according to the protocol and to determine the conversion ratio for IV morphine to oral methadone that was used. Secondary objectives were to describe the methadone dosage used and the clinical outcomes, to evaluate adjustments to methadone dosing, and to report the incidence of adverse effects.

METHODS

A retrospective analysis of charts was conducted for pediatric patients who had received morphine by continuous IV infusion for 5 days or longer followed by methadone in the PICU between May 2008 and August 2009. Validated scoring systems (the Withdrawal Assessment Tool and the State Behavioral Scale) were used to assess symptoms of withdrawal and degree of sedation, respectively.

RESULTS

Forty-three patients were included in the study, with median age of 8 months (range 0.25-201 months). For 31 patients (72%), the protocol was not used, and there were no patients for whom the protocol was followed to completion. The median duration of weaning was 10 days (range 0-91 days). The conversion ratio for IV morphine to oral methadone was 1:0.78 for anticipated 5-day weaning and 1:0.98 for anticipated 10-day weaning. During the first 10 days of weaning, 18 patients (42%) experienced withdrawal symptoms. The methadone dose was increased for 11 (26%) of the 43 patients. Patients were sedated for a median of 1 day (range 0-9 days), were comfortable for a median of 6.5 days (range 1-64 days), and were agitated for a median of 2.5 days (range 0-23 days). Naloxone was required for 2 patients.

CONCLUSIONS

The institution's methadone protocol was not followed consistently during the study period, and practices for transitioning from morphine by continuous IV infusion to methadone with tapering were also inconsistent. Further studies are needed to determine the optimal conversion ratio for morphine to methadone and the optimal tapering regimen to minimize withdrawal symptoms and adverse events.

Pharmacology of commonly used analgesics and sedatives in the ICU: benzodiazepines, propofol, and opioids

The ideal sedative or analgesic agent should have a rapid onset of activity, a rapid recovery after drug discontinuation, a predictable dose response, a lack of drug accumulation,and no toxicity. Unfortunately, none of the earlier analgesics, the benzodiazepines,or propofol share all of these characteristics. Patients who are critically ill experience numerous physiologic derangements and commonly require high doses and long durations of analgesic and sedative therapy. There is a paucity of well designed clinical trials evaluating the safety and efficacy of earlier sedative and analgesic agents in the ICU. In addition, the ever-changing dynamics of patients who are critically ill makes the use of sedation a continual challenge during the course of each patient’s admission. To optimize care, clinicians should be familiar with the many pharmacokinetic, pharmacodynamic, and pharmacogenetic variables that can affect the safety and efficacy of sedatives and analgesics.

A trial of methadone tapering schedules in pediatric intensive care unit patients exposed to prolonged sedative infusions

OBJECTIVES

To compare the efficacy of a low-dose methadone tapering schedule to a high-dose methadone tapering schedule in pediatric intensive care unit patients exposed to infusions of fentanyl, with or without infusions of midazolam, for ≥ 5 days.

DESIGN

Prospective, double-blind, randomized trial.

SETTING

Pediatric intensive care unit in a tertiary care children's hospital.

PATIENTS

Seventy-eight patients, 74 of whom had been receiving infusions of both fentanyl and midazolam, were randomized. Forty-one patients were randomized to the low-dose methadone group and 37 were randomized to the high-dose methadone group. Sixty patients successfully completed the trial, 34 were in the low-dose methadone group, and 26 were in the high-dose methadone group.

INTERVENTIONS

Patients were randomized to receive methadone either at a starting dose of 0.1 mg/kg/dose (low-dose methadone group) or at a starting dose based on both the patient's weight and the most recent fentanyl infusion rate (high-dose methadone group). In each group, methadone was administered every 6 hrs for the first 24 hrs and then every 12 hrs for the second 24 hrs. The methadone was then decreased to once daily and tapered off over the next 10 days. Patients were monitored for withdrawal symptoms using the Modified Narcotic Withdrawal Score.

MEASUREMENTS AND MAIN RESULTS

The percentage of patients who successfully completed the 10-day methadone taper was the same in the low-dose methadone group as in the high-dose methadone group (56% vs. 62%; p = .79). Patients that failed to complete the assigned methadone taper had a greater total fentanyl dose and longer pediatric intensive care unit length of stay compared to patients who completed the assigned methadone taper.

CONCLUSIONS

Patients who received infusions of fentanyl for at least 5 days were just as likely to complete a low-dose methadone taper as a high-dose methadone taper. Because of the risks of both withdrawal and oversedation with any fixed methadone schedule, the methadone dose must be adjusted according to each patient's response.

Disaster after the plaster. Fentanyl withdrawal symptoms in a curable hospice patient

Opioids have been used for thousands of years for pain relief. Transdermal fentanyl (TDF) is a synthetic opioid that is prescribed for the treatment of chronic pain. This clinical lesson demonstrates that TDF may be easy to start but sometimes difficult to stop. Like any other opioid there is a substantial risk of physical dependence and subsequent withdrawal symptoms after discontinuation of the drug. Here, we present a case of a hospice patient who developed withdrawal symptoms after a first TDF tapering attempt according to the manufacturer's instructions. A second, more gradual tapering regimen did not result in withdrawal symptoms. The mechanisms and treatment modalities for physical dependence along with a tailor-made tapering strategy that is suitable for general practice are presented in this clinical lesson.

Tolerance and withdrawal from prolonged opioid use in critically ill children

OBJECTIVE

After prolonged opioid exposure, children develop opioid-induced hyperalgesia, tolerance, and withdrawal. Strategies for prevention and management should be based on the mechanisms of opioid tolerance and withdrawal.

PATIENTS AND METHODS

Relevant manuscripts published in the English language were searched in Medline by using search terms "opioid," "opiate," "sedation," "analgesia," "child," "infant-newborn," "tolerance," "dependency," "withdrawal," "analgesic," "receptor," and "individual opioid drugs." Clinical and preclinical studies were reviewed for data synthesis.

RESULTS

Mechanisms of opioid-induced hyperalgesia and tolerance suggest important drug- and patient-related risk factors that lead to tolerance and withdrawal. Opioid tolerance occurs earlier in the younger age groups, develops commonly during critical illness, and results more frequently from prolonged intravenous infusions of short-acting opioids. Treatment options include slowly tapering opioid doses, switching to longer-acting opioids, or specifically treating the symptoms of opioid withdrawal. Novel therapies may also include blocking the mechanisms of opioid tolerance, which would enhance the safety and effectiveness of opioid analgesia.

CONCLUSIONS

Opioid tolerance and withdrawal occur frequently in critically ill children. Novel insights into opioid receptor physiology and cellular biochemical changes will inform scientific approaches for the use of opioid analgesia and the prevention of opioid tolerance and withdrawal.

Opioid and benzodiazepine withdrawal syndromes in the paediatric intensive care unit: a review of recent literature

AIMS AND OBJECTIVES

This paper aims to critically review and analyse available literature to inform and advance patient care.

BACKGROUND

Withdrawal syndromes related to the routine administration of sedation and analgesia in paediatric intensive care unit (PICU) have been recognized since the 1990 s. Common symptoms include tremors, agitation, inconsolable crying and sleeplessness.

SEARCH STRATEGIES

A critical review was undertaken to assess developments in this area. Four databases were searched using Ovid Online. These were Ovid Medline, CINAHL, BNI and Embase. Key terms included were 'Paediatric', 'Sedation', 'Withdrawal' and 'Intensive care'.

INCLUSION AND EXCLUSION CRITERIA

Articles from 1980 onwards were reviewed for their relevance to paediatric iatrogenic withdrawal. Additionally, seminal work from the 1970s was included. Because of the scarcity of literature, relevant editorials and opinion pieces were included.

RESULTS

A total of 2,232,586 papers resulted from keyword searches. Use of Boolean operators to combine terms reduced the number of results to 62. Exclusion criteria reduced the number of suitable papers to 20. Tracking reference lists yielded a further 18 papers. In total, 38 papers were retrieved examining 1375 patients. Four papers surveyed drug usage on PICU, 14 listed withdrawal symptoms, 4 described the frequency of withdrawal in the PICU population, 9 described risk factors, 4 presented or validated clinical tools and 14 describe treatment strategies.

CONCLUSIONS

Withdrawal syndromes may affect 20% of exposed children and are related to infusion duration and total dose. Fifty-one symptoms are described in the literature. Future studies need accurate, validated clinical tools to be effective. Risk factors, signs and symptoms have been identified, and validation studies must now take place.

RELEVANCE TO CLINICAL PRACTICE

Withdrawal syndromes continue to be widespread and difficult to diagnose. Awareness of their causes and treatments should influence clinical decisions at the bedside.

Methadone analgesia for children with advanced cancer

BACKGROUND

Methadone is frequently used in the treatment of adults with advanced cancer. A criticism of relevant research is the use of single or fixed doses, which does not reflect use in clinical practice. Literature about use of methadone in the treatment of pediatric patients is limited to case reports. The objective of this study is to describe methadone use as primary opioid analgesic for advanced pediatric cancer over a 6.5-year period.

PROCEDURE

All 17 patients who received methadone as their primary opioid analgesic through the Northern Alberta Children's Cancer Program from January 2000 to June 2007 were included. Children who received combination opioid therapy were excluded.

RESULTS

Rotation to methadone was usually by a complete switch from primary opioid. Conversion ratios of morphine equivalent daily dose (MEDD)/methadone daily dose (TMDD) ranged widely from 1:2 in one patient with sudden pain crisis just prior to death, to 60:1 in a patient who had been treated with opioids for months. Methadone was used for a total of 925 patient-days. There were no significant adverse events in any patient, and all but one patient remained on methadone until the time of their death. Clinically, the effectiveness of analgesia clearly improved at time of conversion in 16 patients.

CONCLUSION

With close monitoring, methadone therapy can be done safely in pediatric oncology patient populations in both inpatient and outpatient settings. Our experience suggests improvement in analgesia with the use of methadone, with 16 patients remaining on methadone until they died.

Withdrawal symptoms in critically ill children after long-term administration of sedatives and/or analgesics: a first evaluation

OBJECTIVE

To establish frequencies of benzodiazepine and opioid withdrawal symptoms, and correlations with total doses and duration of administration.

DESIGN

A prospective, repeated-measures design.

SETTING

Two pediatric intensive care units in a university children's hospital.

PATIENTS

Seventy-nine children, aged 0 days to 16 yrs, who received intravenous midazolam and/or opioids for >5 days.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Pediatric intensive care unit nurses assessed withdrawal symptoms using the Sophia Benzodiazepine and Opioid Withdrawal Checklist, which includes all withdrawal symptoms (n = 24) described in the pediatric literature. Over 6 months, 2188 observations in 79 children were recorded. Forty-two percent of observations were performed within 24 hrs after tapering off or discontinuation of medication. Symptoms representing overstimulation of the central nervous system, such as anxiety, agitation, grimacing, sleep disturbance, increased muscle tension, and movement disorder, were observed in >10% of observations. Of symptoms reflecting gastrointestinal dysfunction, diarrhea and gastric retention were most frequently observed. Tachypnea, fever, sweating, and hypertension as manifestations of autonomic dysfunction were observed in >13% of observations. The Spearman's rank-correlation coefficient between total doses of midazolam and maximum sum score (of the Sophia Benzodiazepine and Opioid Withdrawal Checklist) was .51 (p < 0.001). The correlation between total doses of opioids and the maximum sum score was .39 (p < 0.01). A significant correlation (.52; p < 0.001) was also found between duration of use and maximum sum score.

CONCLUSIONS

This is the first study to report frequencies of all 24 withdrawal symptoms observed in children after decrease or discontinuation of benzodiazepines and/or opioids. Agitation, anxiety, muscle tension, sleeping <1 hr, diarrhea, fever, sweating, and tachypnea were observed most frequently. Longer duration of use and high dosing are risk factors for development of withdrawal symptoms in children.

Methadone

Methadone hydrochloride is an old drug that has been in vogue off and on. It has complex pharmacodynamics and can be potentially fatal in inexperienced settings. Drug switching from an opioid to methadone or vice versa requires knowledge of equianalgesic dosing. It is critical when using the drug to monitor for signs and symptoms of toxicity so that overdosing or toxicity can be identified in a timely manner. This review discusses these important topics so that methadone can be used safely and effectively.

Withdrawal symptoms in children after long-term administration of sedatives and/or analgesics: a literature review. "Assessment remains troublesome"

BACKGROUND

Prolonged administration of benzodiazepines and/or opioids to children in a pediatric intensive care unit (PICU) may induce physiological dependence and withdrawal symptoms.

OBJECTIVE

We reviewed the literature for relevant contributions on the nature of these withdrawal symptoms and on availability of valid scoring systems to assess the extent of symptoms.

METHODS

The databases PubMed, CINAHL, and Psychinfo (1980-June 2006) were searched using relevant key terms.

RESULTS

Symptoms of benzodiazepine and opioid withdrawal can be classified in two groups: central nervous system effects and autonomic dysfunction. However, symptoms of the two types show a large overlap for benzodiazepine and opioid withdrawal. Symptoms of gastrointestinal dysfunction in the PICU population have been described for opioid withdrawal only. Six assessment tools for withdrawal symptoms are used in children. Four of these have been validated for neonates only. Two instruments are available to specifically determine withdrawal symptoms in the PICU: the Sedation Withdrawal Score (SWS) and the Opioid Benzodiazepine Withdrawal Scale (OBWS). The OBWS is the only available assessment tool with prospective validation; however, the sensitivity is low.

CONCLUSIONS

Withdrawal symptoms for benzodiazepines and opioids largely overlap. A sufficiently sensitive instrument for assessing withdrawal symptoms in PICU patients needs to be developed.

Population-based analysis of methadone distribution and metabolism using an age-dependent physiologically based pharmacokinetic model

Limited pharmacokinetic (PK) and pharmacodynamic (PD) data are available to use in methadone dosing recommendations in pediatric patients for either opioid abstinence or analgesia. Considering the extreme inter-individual variability of absorption and metabolism of methadone, population-based PK would be useful to provide insight into the relationship between dose, blood concentrations, and clinical effects of methadone. To address this need, an age-dependent physiologically based pharmacokinetic (PBPK) model has been constructed to systematically study methadone metabolism and PK. The model will facilitate the design of cost-effective studies that will evaluate methadone PK and PD relationships, and may be useful to guide methadone dosing in children. The PBPK model, which includes whole-body multi-organ distribution, plasma protein binding, metabolism, and clearance, is parameterized based on a database of pediatric PK parameters and data collected from clinical experiments. The model is further tailored and verified based on PK data from individual adults, then scaled appropriately to apply to children aged 0-24 months. Based on measured variability in CYP3A enzyme expression levels and plasma orosomucoid (ORM2) concentrations, a Monte-Carlo-based simulation of methadone kinetics in a pediatric population was performed. The simulation predicts extreme variability in plasma concentrations and clearance kinetics for methadone in the pediatric population, based on standard dosing protocols. In addition, it is shown that when doses are designed for individuals based on prior protein expression information, inter-individual variability in methadone kinetics may be greatly reduced.

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.

A prospective evaluation of opioid weaning in opioid-dependent pediatric critical care patients

Critically ill children are treated with opioid medication in an attempt to decrease stress and alleviate pain during prolonged pediatric intensive care. This treatment plan places children at risk for opioid dependency. Once dependent, children need to be weaned or risk development of a withdrawal syndrome on abrupt cessation of medication. We enrolled opioid-dependent children into a prospective, randomized trial of 5- versus 10-day opioid weaning using oral methadone. Children exposed to opioids for an average of 3 wk showed no difference in the number of agitation events requiring opioid rescue (3 consecutive neonatal abstinence scores >8 every 2 h) in either wean group. Most of the events requiring rescue occurred on day 5 and 6 of the wean in both treatment groups. Patients may be able to be weaned successfully in 5 days once converted to oral methadone, with a follow-up period after medication wean to observe for a delayed withdrawal syndrome.