Clonidine in the sedation of mechanically ventilated children: a pilot randomized trial

Age-specific vulnerability and high prevalence of delirium in pediatric intensive care based on a prospective cohort study

BACKGROUND

Delirium, a neuropsychiatric syndrome characterized by acute disruptions in attention and awareness, significantly impacts children in Pediatric Intensive Care Units (PICUs), leading to prolonged hospitalization, increased infection risk, and dependence on mechanical ventilation. Despite growing recognition, its true burden and risk factors in children remain poorly understood. This prospective cohort study investigated the prevalence, characteristics, and potential therapeutic targets for delirium in 890 children admitted to a tertiary PICU between January and December 2022. Delirium was screened every 12 hours using the validated Cornell Assessment of Pediatric Delirium (CAPD). We analyzed data on demographics, comorbidities, medications, interventions, and clinical outcomes to identify associations with the development of delirium. Our study revealed a high prevalence of delirium, affecting 69.4% (95% CI: 66.33-72.3) of admitted children. Notably, infants were disproportionately affected, accounting for 33.5% of delirium cases. Respiratory diagnoses were significantly associated with delirium (78.6%), while oncology cases had the lowest prevalence (29.4%). Opioid use was identified as a risk factor, increasing the risk of delirium by 45.2%. Furthermore, 97.6% of children with withdrawal syndrome also experienced delirium, highlighting a strong association between these conditions. Delirium was significantly associated with longer PICU stays, and all 20 mortalities during the study period occurred in delirious patients. The adjusted odds ratios from multi-level regression modeling further elucidated the risk factors associated with the development of delirium. This study demonstrates a high prevalence of delirium in PICUs, with infants and those with respiratory diagnoses being particularly vulnerable. Opioid use and withdrawal syndrome emerged as risk factors. Further research is needed to elucidate the mechanisms underlying these associations and develop targeted interventions to prevent, manage, and improve outcomes for children suffering from delirium in critical care settings.

Use of continuous infusion of clonidine for sedation in critically ill infants and children

BACKGROUND

Adequate sedation and analgesia are required for critically ill children in order to minimize discomfort, reduce anxiety, and facilitate care. This is commonly achieved through a combination of opioids and benzodiazepines. Prolonged use of these agents is associated with tolerance and withdrawal. Clonidine as an adjunctive sedative agent may reduce sedation-related adverse events.

OBJECTIVE

Our first aim was to describe the indication for clonidine administration and its secondary effects in a mixed cohort of critically ill children. Our secondary aim was to measure the consumption of sedatives during two study periods: before and after the use of clonidine in our pediatric intensive care unit (PICU).

METHODS

This was a single-center study conducted in a tertiary PICU and encompassed retrospective chart review of patients who received clonidine between November 2013 and April 2015. We collected data on clonidine dosage, duration of administration, indication for the prescription, and potential side effects. We analyzed the total consumption of sedatives over 18 months, before and after the introduction of clonidine in our sedation protocol.

RESULTS

A total of patients received clonidine, with a mean age of 2.2 ± 2.8 years. The primary reason for intensive care admission was respiratory failure (48%). The main indication for clonidine administration was increasing requirement for morphine and midazolam (60%). The mean duration of clonidine infusion was 9 ± 7.3 days. Bradycardia and hypotension occurred in five patients (11.6%) and nine patients (21%), respectively. These side effects did not result in any major intervention. Younger age was a risk factor for clonidine-associated bradycardia. We observed a significant decrease in morphine and midazolam consumption with clonidine as a comedication. Compared with the pre-study period, consumption decreased by 19.7% for morphine and by 59% for midazolam (calculated as milligram/admission).

CONCLUSION

Continuous infusion of clonidine in critically ill children is safe and effective. Clonidine is a sedative-sparing agent and this can help reduce complications associated with prolonged use of opioids and benzodiazepines.

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

OBJECTIVES

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

DESIGN

Scoping review.

DATA SOURCES

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

STUDY SELECTION

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

DATA EXTRACTION

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

RESULTS

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

CONCLUSIONS

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

Safety of clonidine used for long-term sedation in paediatric intensive care: A systematic review

AIM

Although not approved, the α-adrenoceptor agonist clonidine is considered an option for long-term sedation protocols in paediatric intensive care. We reviewed adverse effects of clonidine occurring in this indication.

METHODS

Relevant literature was systematically identified from PubMed and Embase. We included interventional and observational studies on paediatric patients admitted to intensive care units and systemically long-term sedated with clonidine-containing regimes. In duplicates, we conducted standardised and independent full-text assessment and extraction of safety data.

RESULTS

Data from 11 studies with 909 patients were analysed. The studies were heterogeneous regarding patient characteristics (age groups, comorbidity, or comedication) and sedation regimes (dosage, route, duration, or concomitant sedatives). Just four randomised controlled trials (RCTs) and one observational study had comparison groups, using placebo or midazolam. For safety outcomes, our validity evaluation showed low risk of bias only in three studies. All studies focused on haemodynamic problems, particularly bradycardia and hypotension. Observed incidences or subsequent interventions never caused concerns. However, only two RCTs allowed meaningful comparisons with control groups. Odds ratios showed no significant difference between the groups, but small sample sizes (50 and 125 patients) must be considered; pooled analyses were not reasonable.

CONCLUSION

All evaluated studies concluded that the use of clonidine in paediatric intensive care units is safe. However, a valid characterisation of the safety profile remains challenging due to limited, biased and heterogeneous data and missing investigation of long-term effects. This evaluation demonstrates the lack of data, which prevents reliable conclusions on the safety of clonidine for long-term sedation in critically ill children. For an evidence-based use, further studies are needed.

Total Daily Production and Periodicity of Melatonin Metabolite in Critically Ill Children

OBJECTIVES

To determine whether total daily 6-sulfatoxymelatonin excretion and diurnal variation of melatonin secretion was maintained during the early phase of PICU admission through examination of the melatonin urinary metabolite, 6-sulfatoxymelatonin.

DESIGN

Exploratory prospective, observational study.

SETTING

Twelve-bed medical-surgical PICU of a Children's Hospital.

PATIENTS

Fifty children 3 months to 18 years old enrolled within 24 hours of PICU admission with access for urinary sampling.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Urine samples were collected at 4-hour intervals for 24 hours and stored at -80C. 6-sulfatoxymelatonin was determined in duplicate by direct enzyme-linked immunosorbent assay. Patients were heterogeneous for diagnosis, had a mean age of 8.1 years (SD = 6.1 yr), and median (interquartile range) Pediatric Risk of Mortality III of 10 (4-13). Mean (SD) total daily 6-sulfatoxymelatonin production was 30.0 µg (25.6 µg) for the first 24 hours, which did not differ significantly from the means on days 2 (p = 0.56) or 3 (p = 0.29), and was similar to literature controls. Mean 6-sulfatoxymelatonin production for the population fit a periodic function well, with a reliable amplitude of 326 ng/hr and peak excretion from 04:00 to 08:00 (F = 4.4, p = 0.01), even when 6-sulfatoxymelatonin was corrected for body weight (F = 3.4, p = 0.03) and when sedation was included in the model (F = 3.95, p = 0.004). There was no significant correlation between lighting and 6-sulfatoxymelatonin excretion at any time period (R values: 0.11-0.25, p = 0.10-0.94). Mean 6-sulfatoxymelatonin excretion did not fit the model for a periodic function well for the subpopulations studied (sepsis [n = 18, F = 1.1, p = 0.32], respiratory failure requiring deep sedation [n = 10, F = 0.4, p = 0.66], and neurologic injury [n = 7, F = 0.6, p = 0.55]).

CONCLUSIONS

Total daily and diurnal variation of 6-sulfatoxymelatonin excretion is heterogeneously maintained early in pediatric critical illness. However, this may not hold true for specific diagnostic categories.

The Impact of a Clonidine Transition Protocol on Dexmedetomidine Withdrawal in Critically Ill Pediatric Patients

OBJECTIVES

This study describes our experience with a clonidine transition protocol to prevent dexmedetomidine (DEX) withdrawal in critically ill pediatric patients.

METHODS

Retrospective review of electronic medical records of patients in the pediatric intensive care unit of a single tertiary children's hospital. All patients up to 19 years of age, who received concomitant DEX infusion and enteral clonidine between June 1, 2016, and May 31, 2018, were included.

RESULTS

Two of 24 encounters had DEX restarted for withdrawal (8.3%). Five of 14 encounters who were transitioned to clonidine 2 mcg/kg every 6 hours required an increased dose, and 1 of 10 encounters transitioned to clonidine 4 mcg/kg every 6 hours required an increased dose (36% vs 10%, p = 0.21). For encounters with clonidine dose increases, 5 of 6 had improvements in Withdrawal Assessment Tool-1 (WAT-1) scores. Of these 5 encounters, 4 had decreasing or stable opioid and sedative requirements and 1 was transitioned to methadone. No encounters required discontinuation of clonidine owing to adverse events. Two of 24 encounters met our safety endpoint. One received a fluid bolus during the clonidine transition with no change in clonidine dosing, while the other had clonidine dose decreased for asymptomatic bradycardia.

CONCLUSIONS

The 24 encounters in our retrospective study add to the limited literature available to describe dosing, initiation time, and duration of clonidine to prevent withdrawal from DEX in critically ill pediatric patients. Further research is needed to clarify the optimal dosing and duration of clonidine to prevent DEX withdrawal in pediatric patients.

The Effectiveness of α2 Agonists As Sedatives in Pediatric Critical Care: A Propensity Score-Matched Cohort Study

OBJECTIVES

There is limited evidence supporting the widespread use of α2 agonists (clonidine and dexmedetomidine) in pediatric critical care sedation. This study sought to test the association between the use of α2 agonists and enhanced sedation.

DESIGN

A retrospective observational cohort study was conducted. Noninferiority of time adequately sedated (COMFORT Behavior Score 11-16) while mechanically ventilated was assessed. Secondarily, dosing of opioids and benzodiazepines was examined.

SETTING

Two tertiary PICUs.

PATIENTS

Children were classified into an exposed group, who received an α2 agonist as part of their sedation regimen, and an unexposed group. Groups were matched using propensity score analysis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

One-thousand eighty-five patients were included. The exposed group were adequately sedated 74% (95% CI, 72-75%) of the study time compared with the unexposed group at 70% (95% CI, 67-72%) giving a ratio of 1.06 (95% CI, 1.02-1.10) and a noninferior time adequately sedated. A decrease in time oversedated was observed with 8.1% (95% CI, 4.3-11.9%) less time classified as oversedated in the exposed group. Reduction in morphine use of 0.25 μg/kg/hr (95% CI, -0.68 to 1.18 μg/kg/hr) was not statistically significant. Midazolam use did not decrease and was statistically higher.

CONCLUSIONS

Use of α2 agonists was associated with similar time adequately sedated as a matched unexposed group although no reduction in morphine or benzodiazepine coadministration was observed. There was a shift toward lighter sedation with α2 agonist use.

Analgesics and Sedatives in Critically Ill Newborns and Infants: The Impact on Long-Term Neurodevelopment

Inadequate pain and/or stress management in preterm- and term-born infants has been associated with increased morbidity and even mortality. However, exposure to analgosedatives during early infancy may also be one of the risk factors for subsequent neurodevelopmental impairment, at least in animal studies. Because infants admitted to neonatal or pediatric intensive care units may receive high amounts of these drugs for prolonged periods of time and the majority of these infants nowadays survive to discharge, this is of major concern. A balanced approach that incorporates the assessment and quantification of both wanted effects as well as unwanted side effects is therefore needed. In this article, the optimal dose determination of commonly used analgosedative drugs as well as their potential long-term effects on the developing human brain and neuropsychological functioning are reviewed.

Optimizing clonidine dosage for sedation in mechanically ventilated children: A pharmacokinetic simulation study

BACKGROUND

Clonidine is in widespread off-label use as a sedative in mechanically ventilated children, despite limited evidence of efficacy. A variety of dosage regimens have been utilized in clinical practice and in research studies. Within these studies, clonidine has inconsistently shown useful sedation properties. One of the reasons attributed to the inconsistent signs of efficacy is suboptimal clonidine dosing.

AIMS

This study aims to propose a target plasma concentration and simulate clonidine pharmacokinetics (PK) in a cohort of mechanically ventilated children to evaluate the adequacy of clonidine dosage regimens used in clinical practice and research studies.

METHODS

A literature search was undertaken to identify a clonidine pharmaockinetic-pharmacodynamics (PKPD) model, from which a target concentration for sedation was defined. Using a previously published PK model, the projected plasma concentrations of 692 mechanically ventilated children (demographics taken from a recent study) were generated. Doses from recently published clinical studies were investigated. Adequacy of each regimen to attain therapeutic clonidine plasma concentrations was assessed.

RESULTS

A target plasma concentration of above 2 µg/L was proposed. Nine dosage regimens (four intravenous boluses, four intravenous infusions, and one nasogastric route boluses) were evaluated ranging from 1 µg/kg eight hourly intravenous boluses to a regimen up to 3 µg/kg/hr continuous intravenous infusion. Regimens with a loading dose of 2 µg/kg followed by variable continuous infusion of up to 2 µg/kg/hr titrated according to sedation score appear most suitable. Doses should be halved in neonates.

CONCLUSION

The variety of dosage regimens in the previous studies of clonidine along with difficulties in the conduct of interventional studies may have contributed to the lack of efficacy data to support its use. Simulations of clonidine plasma concentrations based on known population pharmacokinetic parameters suggest a loading dose followed by higher than current practice maintenance dose infusion is required to achieve adequate steady-state concentrations early in treatment. Further PKPD studies will aid in the determination of the optimal clonidine dosage regimen.

Clonidine in pediatric anesthesia: the new panacea or a drug still looking for an indication?

PURPOSE OF REVIEW

Clonidine, an α2-receptor agonist is a widely used drug in pediatrics with a large scope of indications ranging from prevention of postoperative emergence agitation, analgesia, anxiolysis, sedation, weaning to shivering. In the era of 'opioid-free' medicine with much attention be directed toward increasing problems with opioid use, clonidine due to its global availability, low cost and safety profile has become an even more interesting option.

RECENT FINDINGS

Increasing evidence from randomised clinical trials support the use of clonidine in healthy children in the perioperative setting. Clonidine appears to significantly reduce postoperative emergence agitation, opioid consumption, shivering, nausea and vomiting. In addition, emerging evidence support the use of clonidine for sedation of critically ill children in ICUs. In this review, the current evidence for clonidine in pediatrics is described and analyzed including a meta-analysis for prevention of emergence agitation.

SUMMARY

Clonidine appears a safe and beneficial drug with moderate to high-quality evidence supporting its use in pediatric anesthesia. However, for some indications and populations such as children younger than 12 months old and those with hemodynamic instability, there is an urgent need for high-quality trials.

Pharmacological Strategies for Decreasing Opioid Therapy and Management of Side Effects from Chronic Use

As awareness increases about the side effects of opioids and risks of misuse, opioid use and appropriate weaning of opioid therapies have become topics of significant clinical relevance among pediatric populations. Critically ill hospitalized neonates, children, and adolescents routinely receive opioids for analgesia and sedation as part of their hospitalization, for both acute and chronic illnesses. Opioids are frequently administered to manage pain symptoms, reduce anxiety and agitation, and diminish physiological stress responses. Opioids are also regularly prescribed to youth with chronic pain. These medications may be prescribed during the initial phase of a diagnostic workup, during an emergency room visit; as an inpatient, or on an outpatient basis. Following treatment for underlying pain conditions, it can be challenging to appropriately wean and discontinue opioid therapies. Weaning opioid therapy requires special expertise and care to avoid symptoms of increased pain, withdrawal, and agitation. To address this challenge, there have been enhanced efforts to implement opioid-reduction during pharmacological therapies for pediatric pain management. Effective pain management therapies and their outcomes in pediatrics are outside the scope of this paper. The aims of this paper were to: (1) Review the current practice of opioid-reduction during pharmacological therapies; and (2) highlight concrete opioid weaning strategies and management of opioid withdrawal.

Hemodynamic Tolerance to IV Clonidine Infusion in the PICU

OBJECTIVES

Clonidine is an antihypertensive drug used for analgosedation in the PICU. Lack of reliable data on its hemodynamic tolerance limits its use. This study explores the hemodynamic tolerance of IV clonidine infusion in a broad population of children with high severity of disease.

DESIGN

Retrospective analysis of prospectively collected data.

SETTING

A tertiary and quaternary referral PICU.

PATIENTS

Critically ill children age 0-18 years old who received an IV clonidine infusion for analgosedation of at least 1 hour.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary endpoints were the prevalences of bradycardia and hypotension. Secondary endpoints were changes in heart rate, blood pressure, Vasoactive-Inotropic Score, COMFORT Behavior score (a sedation scoring scale), and body temperature during the infusion. The association of bradycardia with other hemodynamic variables was explored, as well as potential risk factors for severe bradycardia. One-hundred eighty-six children (median age, 12.9 mo [interquartile range, 3.5-60.6 mo]) receiving a maximum median clonidine infusion of 0.7 µg/kg/hr (interquartile range, 0.3-1.5) were included. Severe bradycardia and systolic hypotension occurred in 72 patients (40.2%) and 105 patients (58%), respectively. Clonidine-associated bradycardia was hemodynamically well tolerated, as it was not related with hypotension and the need for vasoactive drugs decreased in parallel with a sedation score guided clonidine infusion rate increase. Younger age was the only identified risk factor for clonidine-associated bradycardia.

CONCLUSIONS

Although administration of clonidine is often associated with bradycardia and hypotension, these complications do not seem clinically significant in a mixed PICU population with a high degree of disease severity. Clonidine may have a vasoactive-inotropic sparing effect.

Iatrogenic Opioid Withdrawal in Critically Ill Patients: A Review of Assessment Tools and Management

OBJECTIVE

To (1) provide an overview of the epidemiology, clinical presentation, and risk factors of iatrogenic opioid withdrawal in critically ill patients and (2) conduct a literature review of assessment and management of iatrogenic opioid withdrawal in critically ill patients.

DATA SOURCES

We searched MEDLINE (1946-June 2017), EMBASE (1974-June 2017), and CINAHL (1982-June 2017) with the terms opioid withdrawal, opioid, opiate, critical care, critically ill, assessment tool, scale, taper, weaning, and management. Reference list of identified literature was searched for additional references as well as www.clinicaltrials.gov .

STUDY SELECTION AND DATA EXTRACTION

We restricted articles to those in English and dealing with humans.

DATA SYNTHESIS

We identified 2 validated pediatric critically ill opioid withdrawal assessment tools: (1) Withdrawal Assessment Tool-Version 1 (WAT-1) and (2) Sophia Observation Withdrawal Symptoms Scale (SOS). Neither tool differentiated between opioid and benzodiazepine withdrawal. WAT-1 was evaluated in critically ill adults but not found to be valid. No other adult tool was identified. For management, we identified 5 randomized controlled trials, 2 prospective studies, and 2 systematic reviews. Most studies were small and only 2 studies utilized a validated assessment tool. Enteral methadone, α-2 agonists, and protocolized weaning were studied.

CONCLUSION

We identified 2 validated assessment tools for pediatric intensive care unit patients; no valid tool for adults. Management strategies tested in small trials included methadone, α-2 agonists, and protocolized sedation/weaning. We challenge researchers to create validated tools assessing specifically for opioid withdrawal in critically ill children and adults to direct management.

The CLOSED trial; CLOnidine compared with midazolam for SEDation of paediatric patients in the intensive care unit: study protocol for a multicentre randomised controlled trial

INTRODUCTION

Sedation is an essential part of paediatric critical care. Midazolam, often in combination with opioids, is the current gold standard drug. However, as it is a far-from-ideal agent, clonidine is increasingly being used in children. This drug is prescribed off-label for this indication, as many drugs in paediatrics are. Therefore, the CLOSED trial aims to provide data on the pharmacokinetics, safety and efficacy of clonidine for the sedation of mechanically ventilated patients in order to obtain a paediatric-use marketing authorisation.

METHODS AND ANALYSIS

The CLOSED study is a multicentre, double-blind, randomised, active-controlled non-inferiority trial with a 1:1 randomisation between clonidine and midazolam. Both treatment groups are stratified according to age in three groups with the same size: <28 days (n=100), 28 days to <2 years (n=100) and 2-18 years (n=100). The primary end point is defined as the occurrence of sedation failure within the study period. Secondary end points include a pharmacokinetic/pharmacodynamic relationship, pharmacogenetics, occurrence of delirium and withdrawal syndrome, opioid consumption and neurodevelopment in the neonatal age group. Logistic regression will be used for the primary end point, appropriate statistics will be used for the secondary end points.

ETHICS

Written informed consent will be obtained from the parents/caregivers. Verbal or deferred consent will be used in the sites where national legislation allows. The study has institutional review board approval at recruiting sites. The results will be published in a peer-reviewed journal and shared with the worldwide medical community.

TRIAL REGISTRATION

EudraCT: 2014-003582-24; Clinicaltrials.gov: NCT02509273; pre-results.

Effectiveness of α2agonists for sedation in paediatric critical care: study protocol for a retrospective cohort observational study

INTRODUCTION

Mechanically ventilated children in paediatric intensive care units are commonly administered analgesics and sedative agents to minimise pain and distress and facilitate cooperation with medical interventions. Opioids and benzodiazepines are the most common analgesic and sedative agents but have safety concerns. The α₂ agonists clonidine and dexmedetomidine are alternative sedatives in use despite neither having robust evidence to support their use. Studies evaluating effectiveness of α₂ agonists to date have not focused on sedation-based outcomes instead focusing on opioid-sparing properties and ventilation outcomes. The aim of this study is to evaluate if an opioid-based sedation regimen, with an α₂ agonist adjunct (clonidine or dexmedetomidine), produces a non-inferior proportion of time adequately sedated compared with a control group without an α₂ agonist adjunct, while conferring potential additional benefits such as reduced opioid administration and less exposure to potential additional agents such as benzodiazepines.

METHODS AND ANALYSIS

We will conduct a retrospective cohort study in two Irish paediatric intensive care units using clinical information on patient characteristics, sedation scores and drug use. Eligible children admitted between January 2014 and June 2016 who were mechanically ventilated and received an opioid infusion will be included. Patients will be categorised into two exposure categories (received an α₂ agonist or did not receive an α₂ agonist) and the time adequately sedated (measured using the COMFORT Behaviour Score) will be calculated using interpolation of nursing sedation scores at each recorded time point. At least 150 per group is planned for inclusion to ensure adequate study power. Propensity score matching will be used in analysis to account for potential confounding by indication.

ETHICS AND DISSEMINATION

The study has been approved by the ethics committees of both hospitals. Dissemination will occur via local, national and international presentations for academic and healthcare audiences as well as through peer reviewed publications.

Clonidine for sedation in the critically ill: a systematic review and meta-analysis

Background

This systematic review and meta-analysis investigates the efficacy and safety of clonidine as a sedative in critically ill patients requiring invasive mechanical ventilation.

Methods

We performed a comprehensive search of MEDLINE, EMBASE, CINAHL and the Cochrane trial registry. We identified RCTs that compared clonidine to any non-clonidine regimen in critically ill patients, excluding neonates, requiring mechanical ventilation. The GRADE method was used to assess certainty of evidence.

Results

We included eight RCTs (n = 642 patients). In seven of the trials clonidine was used for adjunctive rather than stand-alone sedation. There was no difference in the duration of mechanical ventilation (mean difference (MD) 0.05 days, 95% confidence interval (CI) = -0.65 to 0.75, I² = 86%, moderate certainty), ICU mortality (relative risk (RR) 0.98, 95% CI = 0.51 to 1.90, I² = 0%, low certainty), or ICU length of stay (MD 0.04 days, 95% CI = -0.46 to 0.53, I² = 16%, moderate certainty), with clonidine. There was a significant reduction in the total dose of narcotics (standard mean difference (SMD) -0.26, 95% CI = -0.50 to -0.02, I² = 0%, moderate certainty) with clonidine use. Clonidine was associated with increased incidence of clinically significant hypotension (RR 3.11, 95% CI = 1.64 to 5.87, I² = 0%, moderate certainty).

Conclusions

Until further RCTs are performed, data remains insufficient to support the routine use of clonidine as a sedative in the mechanically ventilated population. Clonidine may act as a narcotic-sparing agent, albeit with an increased risk of clinically significant hypotension.

Clonidine for Sedation and Analgesia and Withdrawal in Critically Ill Infants and Children

The need for sedation and analgesia and treatment of iatrogenic drug withdrawal is common in critically ill children. First-line therapy typically includes opioid agonists. However, clonidine, a central α₂ agonist, has been suggested as a treatment option for sedation and analgesia and iatrogenic drug withdrawal. Therefore, we conducted a literature search to identify articles evaluating the use of enteral (PO) and transdermal clonidine in critically ill infants and children for sedation and analgesia and treatment of iatrogenic drug withdrawal. The literature search was limited to English-language articles in Medline (1946-May 2016), Embase (1988-May 2016), and International Pharmaceutical Abstracts (1970-May 2016). Reference citations from relevant articles were also reviewed. Ten case reports and studies, representing a total of 114 children receiving clonidine, were included. Fifty patients (43.9%) received clonidine for sedation and analgesia while mechanically ventilated, and 33 (29.0%) received clonidine for treatment or prevention of drug withdrawal. The remaining 31 patients (27.1%) were included in a pharmacokinetic study that did not evaluate clinical outcomes. Seventy-nine patients (69.3%) received PO clonidine, with a dosage range of 2-15 µg/kg/day divided every 6-8 hours. Thirty-five patients (30.7%) received transdermal clonidine, with a dosage range of 2.3-20 µg/kg/day. Whole, cut, and occluded transdermal patches were used in the reports. Patients receiving cut patches had more variable and significantly higher serum clonidine concentrations than those receiving whole patches. Only three studies reported that the PO clonidine dose was tapered at the end of therapy; however, no report specifically described the process. The two most common adverse events reported with PO and transdermal clonidine were bradycardia and hypotension. PO and transdermal clonidine have a potential role for sedation and analgesia and drug withdrawal in critically ill infants and children. The use of cut transdermal patches should be avoided. Future prospective studies are needed to further define clonidine's role as adjunct therapy or monotherapy.

Pharmacological sedation management in the paediatric intensive care unit

Objective

This review addresses sedation management on paediatric intensive care units and possible gaps in the knowledge of optimal sedation strategies. We present an overview of the commonly used sedatives and their pharmacokinetic and pharmacodynamic considerations in children, as well as the ongoing studies in this field. Also, sedation guidelines and current sedation strategies and assessment methods are addressed.

Key findings

This review shows that evidence and pharmacokinetic data are scarce, but fortunately, there is an active research scene with promising new PK and PD data of sedatives in children using new study designs with application of advanced laboratory methods and modelling. The lack of evidence is increasingly being recognized by authorities and legislative offices such as the US Food and Drug Administration (FDA) and European Medicines Agency (EMA).

Conclusion

The population in question is very heterogeneous and this overview can aid clinicians and researchers in moving from practice-based sedation management towards more evidence- or model-based practice. Still, paediatric sedation management can be improved in other ways than pharmacology only, so future research should aim on sedation assessment and implementation strategies of protocolized sedation as well.

Clonidine as a First-Line Sedative Agent After Neonatal Cardiac Surgery: Retrospective Cohort Study

OBJECTIVES

To determine the cardiovascular tolerance of clonidine used as a first-line sedative after cardiac surgery in small infants.

DESIGN

Retrospective chart review.

SETTING

A tertiary and quaternary referral cardiac PICU.

PATIENTS

All infants younger than 2 months who received a clonidine infusion for sedation after cardiac surgery from October 2011 to July 2013.

INTERVENTIONS

None.

MEASUREMENT AND MAIN RESULTS

Heart rate, blood pressure, central venous and left atrial pressure, vasoactive inotropic score, volume of fluid bolus, and lactate and central mixed venous saturation were assessed. Preinfusion values were compared with postinfusion values. Of 224 potentially eligible patients, only 23 infants met inclusion criteria, as most patients only received high doses of morphine and some received midazolam instead of clonidine. Clonidine administration was started at a median of 12 hours after surgery (Q1-Q3, 5-23), and infusion rate was 0.5-2 μg/kg/hr for a median duration of 30 hours (Q1-Q3, 12-54). Heart rate decreased (maximal mean decrease: 12% [149 beats/min (SD, 17) to 131 beats/min (SD, 17)]; p < 0.0001). Apart from a transient and limited drop in diastolic blood pressure of 13% (maximal mean decrease: from 42.8 mm Hg [SD, 5.9] to 37.1 mm Hg [SD, 4.0]; p = 0.018), all other cardiovascular variables were stable or improved. A contemporaneous cohort of patients who received midazolam, did so sooner after surgery, stayed longer in the PICU and showed less favorable hemodynamics.

CONCLUSIONS

IV clonidine as sedative added to morphine in selected patients seems hemodynamically safe. The observed decrease in heart rate and diastolic blood pressure seems of minimal clinical importance as all other hemodynamic variables remained stable or improved. The safety of clonidine given early after cardiac surgery as alternative to midazolam merits further study.

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

OBJECTIVE

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

DATA SOURCES

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

STUDY SELECTION

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

DATA EXTRACTION

Two authors independently screened articles for inclusion.

DATA SYNTHESIS

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

CONCLUSIONS

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

Transition from dexmedetomidine to enteral clonidine for ICU sedation: an observational pilot study

INTRODUCTION

Enteral clonidine represents a potentially less costly alternative to dexmedetomidine for sedation in intensive care unit (ICU) patients. This study describes our practice of transitioning selected adult ICU patients from dexmedetomidine to clonidine with a focus on efficacy, safety, and drug acquisition costs.

METHODS

We conducted a single-center prospective observational pilot study from January through March 2014. Consecutive patients 18 years and older treated with dexmedetomidine and transitioned to clonidine were followed. The transition was assessed in five phases: dexmedetomidine maintenance, transition, clonidine maintenance, clonidine taper, and post clonidine. Efficacy data included any occurrence of significant pain, excessive agitation or oversedation, delirium, and need for ancillary psychoactive medications. Safety data included any occurrence of bradycardia, hypotension, new second- or third-degree atrioventricular node blockade, and clonidine withdrawal syndrome. Drug acquisition cost avoidances were estimated using average wholesale price.

RESULTS

Twenty patients were evaluated. Fifteen (75%) were successfully transitioned from dexmedetomidine within 48 hours of starting clonidine. The initial and maintenance clonidine regimens were 0.3 mg every 6 hours. Clonidine was the sole α2A -receptor agonist administered for 45 hours while in the ICU and for 54 hours outside the ICU. Fentanyl requirements were lower when clonidine was administered as the sole α2A -receptor agonist as compared to dexmedetomidine alone (387 vs. 891 μg/day, p = 0.03). Otherwise, there were no statistically significant differences in efficacy data during the dexmedetomidine and clonidine maintenance phases. No statistically significant differences in safety data were observed. Clonidine withdrawal syndrome criteria were met in one patient. The potential drug acquisition cost avoidance was $819-$2338 per patient during the 3-month study.

CONCLUSIONS

Transitioning from dexmedetomidine to clonidine may be an efficacious, safe, and less costly method of maintaining α2A -receptor agonist therapy in critically ill adults; these results warrant confirmation in expanded studies.

Pain and Sedation Management in Mechanically Ventilated Children

Assessing and managing pain and agitation in critically ill children can be challenging. Multiple factors contribute to the challenges of management, including prior medication exposure, surgical and procedural interventions, pharmacokinetics, and age-related pharmacodynamics making the population heterogeneous. Therefore, individualizing treatment approaches embedded with frequent assessments is likely to improve the management of pain and agitation in critically ill children. Novel approaches to manage pain and agitation continue to evolve and will require ongoing evaluation prior to widespread adoption.

Ethics of drug research in the pediatric intensive care unit

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