Evaluation of an opiate-weaning protocol using methadone in pediatric intensive care unit patients

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.

Sedation and analgesia in the pediatric intensive care unit following laryngotracheal reconstruction

BACKGROUND

Children undergoing laryngotracheal reconstruction (LTR) may remain electively intubated in the pediatric intensive care unit (PICU) for several days following surgery to facilitate wound healing. These patients require sedation and analgesia with or without neuromuscular blockade in order to prevent excessive head and neck movement with resultant tension on the tracheal anastomosis. Achieving this level of immobility features in caring for these children.

AIM

The aims of this article are to describe a variety of commonly used sedation and analgesic agents and to provide guidance as to their optimal use following LTR.

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.

Sedation and analgesia in the pediatric Intensive Care Unit following laryngotracheal reconstruction

Deep levels of sedation and analgesia are needed in the majority of children who require prolonged tracheal intubation after laryngotracheal reconstruction (LTR). Drug doses may be determined most appropriately using validated scoring tools for sedation and analgesia; these scales continue to evolve and are used with increasing regularity in the pediatric intensive care unit (PICU). In this presentation, the validated scoring tools used to assess sedation and analgesia are reviewed, and specific agents used to manage sedation, analgesia, and neuromuscular blockade in the PICU after LTR are discussed.

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.

Critically ill children in non-paediatric intensive care units: a survey, review and proposal for practice

Despite strong arguments in favour of centralising care of critically ill children to paediatric intensive care units, around 2000 children per year are cared for in non-paediatric intensive care units in Australia and New Zealand. This paper reports a survey of consultants from 13 such units that admitted over 50 children in 2002 and 2003, to find out what factors affect the decision to keep critically ill children locally or transfer them to a paediatric intensive care unit and what infrastructure existed to support local care of these children. The results of this survey form the basis for a proposal to improve care of critically ill children in the non-paediatric intensive care units. The four key elements of this proposal are: the use of protocols, routine consultation with the regional paediatric intensive care unit, the use of telemedicine, and enhancing skills and experience of local staff Evidence supporting these measures as well as the evidence for centralising care of critically ill children is reviewed.

Minimizing tolerance and withdrawal to prolonged pediatric sedation: case report and review of the literature

Midazolam and fentanyl infusions are commonly used for prolonged sedation and analgesia in the pediatric intensive care setting. Tolerance and withdrawal are major concerns when these infusions are used for days or weeks. Here, we review the current approaches to prolonged pediatric sedation using midazolam and fentanyl and discuss newer strategies to avoid tolerance and withdrawal syndromes. We report the case of a pediatric burn patient who developed tolerance syndrome and a movement disorder in our institution. We also review the relevant literature and methods of minimizing tolerance and withdrawal. Prolonged sedation is often necessary in treating critically ill children, and tolerance and abstinence syndrome can complicate a successful recovery. Scoring systems can be used to minimize oversedation and to titrate effectively. "Drug cycling," "wake-up protocols," and weaning regimens, possibly combined with adjuvant drugs, are being implemented successfully. Such novel approaches may decrease the incidence of tolerance and withdrawal associated with prolonged sedative and analgesic use.

Opioid analgesia in neonates following cardiac surgery

Pain in the newborn is complex, involving a variety of receptors and mechanisms within the developing nervous system. When pain is generated, a series of sequential neurobiologic changes occur within the central nervous system. If pain is prolonged or repetitive, the developing nervous system could be permanently modified, with altered processing at spinal and supraspinal levels. In addition, pain is associated with a number of adverse physiologic responses that include alterations in circulatory (tachycardia, hypertension, vasoconstriction), metabolic (increased catabolism), immunologic (impaired immune response), and hemostatic (platelet activation) systems. This "stress response" associated with cardiac surgery in neonates could be profound and is associated with increased morbidity and mortality. Neonates undergoing cardiac operations are exposed to extensive tissue damage related to surgery and additional painful stimulation related to endotracheal and thoracostomy tubes that may remain in place for variable periods of time following surgery. In addition, postoperatively neonates endure repeated procedural pain from suctioning of endotracheal tubes, placement of vascular catheters, and manipulation of wounds (eg, sternal closure) and dressings. The treatment and/or prevention of pain are widely considered necessary for humanitarian and physiologic reasons. Improved clinical and developmental outcomes underscore the importance of providing adequate analgesia for newborns who undergo major surgery, mechanical ventilation, and related procedures in the intensive care unit. This article reviews published information regarding opioid administration and associated issues of tolerance and abstinence syndromes (withdrawal) in neonates with an emphasis on those having undergone cardiac surgery.

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.

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.

Methadone dosage for prevention of opioid withdrawal in children

BACKGROUND

Opioids are frequently used for sedation in the Paediatric Intensive Care Unit (PICU). With time the dosing often increases because of tolerance. On cessation of the sedation there is a risk of the opioid withdrawal syndrome. The aim of our study was to evaluate methadone dosing as a risk factor for opioid withdrawal and to determine optimal dose and efficacy of methadone to prevent withdrawal.

METHOD

We undertook a clinical, retrospective, chart review study. Data were analysed from the quality improvement initiative database of a tertiary-care 18 bed PICU.

RESULTS

Data from 30 children who received an opioid infusion for >/=7 days and subsequently received methadone for opioid withdrawal (between January 2000 and July 2001) were analysed. Nurses documented the presence or absence of withdrawal signs daily. Our unit protocol has recommended converting the patient's opioid dose into fentanyl equivalents and a dose of methadone equal to the total daily dose of fentanyl to be given three times a day. Twenty patients had no or minimal withdrawal symptoms and 10 experienced significant withdrawal. Age, weight, PRISM score, lorazepam dose, muscle relaxant use and fentanyl dose were not statistically significantly between these groups. Receiver Operator Characteristics analysis showed that 80% of the suggested methadone dose was effective in minimizing withdrawal symptoms. The odds ratio for withdrawal with <80% of the predicted methadone dose was 21.

CONCLUSIONS

Inadequate methadone is a risk factor for opioid withdrawal. A daily starting methadone dose equivalent to 2.5 times the daily fentanyl dose is effective in minimizing withdrawal symptoms.

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

STUDY OBJECTIVE

To determine if enterally administered methadone can facilitate fentanyl discontinuation and prevent withdrawal in children at high risk for opioid abstinence syndrome.

DESIGN

Retrospective analysis.

SETTING

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

PATIENTS

Twenty-two children (aged 6.1 +/- 5.4 yrs) who received continuous fentanyl infusion for 9 days or longer.

INTERVENTION

Guidelines for initiating enteral methadone, rapidly tapering and discontinuing fentanyl infusions, and tapering methadone were implemented in the PICU. Development of opioid abstinence syndrome was evaluated during fentanyl and methadone dosage reductions and for 72 hours thereafter.

MEASUREMENTS AND MAIN RESULTS

Children received fentanyl by continuous infusion for 17.8 +/- 8.4 days. Peak fentanyl infusion rate was 5.9 +/- 3.8 microg/kg/hour, and the median cumulative dose was 1302 microg/kg (range 354-7535 microg/kg). Methadone 0.50 +/- 0.22 mg/kg/day was begun 1.6 +/- 1.9 days before tapering fentanyl. The fentanyl infusion rate on starting the taper was 5.0 +/- 3.6 microg/kg/hour. Fentanyl was tapered and discontinued in a median of 2.6 days (range 0-11.9 days). Twenty-one patients had no opioid abstinence syndrome during or after fentanyl taper. One patient experienced significant opioid withdrawal after fentanyl discontinuation, which resolved after reinstitution of fentanyl and increasing the dosage of methadone to 0.3 mg/kg every 6 hours. Overall, methadone was tapered and discontinued in 18.2 +/- 11.9 days without precipitating opioid abstinence syndrome.

CONCLUSION

Enteral administration of methadone may expedite fentanyl discontinuation and reduce the risk of withdrawal in critically ill children at high risk for opioid abstinence syndrome.

Efficacy of an enteral 10-day methadone wean to prevent opioid withdrawal in fentanyl-tolerant pediatric intensive care unit patients

OBJECTIVE

To demonstrate the efficacy of a 10-day, single daily dose, enteral methadone weaning protocol for the prevention of opioid withdrawal symptoms in pediatric patients after prolonged fentanyl exposure.

DESIGN

Prospective, observational study.

SETTING

Twenty-four-bed medical-surgical intensive care unit within a 222-bed pediatric teaching hospital.

PATIENTS

Twenty-nine children, aged 1 day to 19.8 yrs, who received methadone to prevent opioid withdrawal after prolonged continuous fentanyl infusion exposure.

INTERVENTIONS

Institution of a standardized methadone weaning protocol.

MEASUREMENTS AND MAIN RESULTS

All 29 patients had received a continuous fentanyl infusion; duration of exposure was 14.5 +/- 9.2 days, cumulative fentanyl dose was 1.93 +/- 1.53 mg/kg, and peak fentanyl infusion was 9.6 +/- 4.3 microg/kg per hr. Twenty-five (86%) of 29 patients successfully completed the methadone wean in 10 days. Withdrawal complications that required a weaning delay were seen in three patients, and one patient expired before completion. Sixteen patients were discharged to complete their weaning schedule at home without incident.

CONCLUSIONS

Opioid withdrawal symptoms in pediatric intensive care unit patients after prolonged fentanyl exposure can be avoided by using an enteral, 10-day, single daily dose methadone weaning protocol.