Sedation and analgesia in paediatric intensive care units: a guide to drug selection and use

Trichloroethanol, an active metabolite of chloral hydrate, modulates tetrodotoxin-resistant Na+ channels in rat nociceptive neurons

BACKGROUND

Chloral hydrate is a sedative-hypnotic drug widely used for relieving fear and anxiety in pediatric patients. However, mechanisms underlying the chloral hydrate-mediated analgesic action remain unexplored. Therefore, we investigated the effect of 2',2',2'-trichloroethanol (TCE), the active metabolite of chloral hydrate, on tetrodotoxin-resistant (TTX-R) Na⁺ channels expressed in nociceptive sensory neurons.

METHODS

The TTX-R Na⁺ current (I_Na) was recorded from acutely isolated rat trigeminal ganglion neurons using the whole-cell patch-clamp technique.

RESULTS

Trichloroethanol decreased the peak amplitude of transient TTX-R I_Na in a concentration-dependent manner and potently inhibited persistent components of transient TTX-R I_Na and slow voltage-ramp-induced I_Na at clinically relevant concentrations. Trichloroethanol exerted multiple effects on various properties of TTX-R Na⁺ channels; it (1) induced a hyperpolarizing shift on the steady-state fast inactivation relationship, (2) increased use-dependent inhibition, (3) accelerated the onset of inactivation, and (4) retarded the recovery of inactivated TTX-R Na⁺ channels. Under current-clamp conditions, TCE increased the threshold for the generation of action potentials, as well as decreased the number of action potentials elicited by depolarizing current stimuli.

CONCLUSIONS

Our findings suggest that chloral hydrate, through its active metabolite TCE, inhibits TTX-R I_Na and modulates various properties of these channels, resulting in the decreased excitability of nociceptive neurons. These pharmacological characteristics provide novel insights into the analgesic efficacy exerted by chloral hydrate.

Procedural Sedation in Congenital Heart Disease

Procedural sedation in patients with congenital heart disease (CHD) is associated with significant morbidity and mortality. It is vital for the practitioner to fully understand the complexity of lesions, their hemodynamics, and the impact of medications commonly used for procedural sedation on the stability of systemic vascular resistance and pulmonary flow. According to the literature, we explain the interaction of the systemic vascular resistance and pulmonary flow in such lesions and divide them into five categories outlined in this article: (1) CHDs with left-to-right shunt with normal pulmonary arterial pressure and resistance, (2) CHD with left-to-right shunt and moderate to severe elevation of pulmonary arterial pressure with near-normal pulmonary vascular resistance, (3) CHD with pulmonary flow dependent on systemic vascular resistance, (4) patients with congenital coronary stenosis and coronary anomalies, and 5) aortic obstructive lesions.

Association of Intravenous Acetaminophen Administration With the Duration of Intravenous Opioid Use Among Hospitalized Pediatric Patients

Importance

Adoption of multimodal pain regimens that incorporate nonopioid analgesic medications to reduce inpatient opioid administration can prevent serious opioid-related adverse effects in children, including tolerance, withdrawal, delirium, and respiratory depression. Intravenous (IV) acetaminophen is in widespread pediatric use; however, its effectiveness as an opioid-sparing agent has not been evaluated in general pediatric inpatients.

Objective

To determine if IV acetaminophen administered prior to IV opioids is associated with a reduction in the total duration of IV opioids administered compared with IV opioids administered without IV acetaminophen in general pediatric inpatients.

Design, Setting, and Participants

This comparative effectiveness research study included data on pediatric inpatients from 274 US hospitals between January 2011 and June 2016 collected from a national database. Outcomes were compared with a propensity score-matched analysis of pediatric inpatients administered IV opioids without IV acetaminophen (control) and those administered IV acetaminophen prior to IV opioids (intervention). Data were analyzed from January 2020 through October 2021.

Exposures

Patients in the intervention group received IV acetaminophen prior to IV opioids. Patients in the control group received IV opioids without IV acetaminophen.

Main Outcomes and Measures

Total duration of all IV opioids administered during a patient's hospitalization.

Results

Of 893 293 pediatric inpatients, a total of 104 579 were included in analysis (median [IQR] age, 1.3 [0-14.7] years; 59 806 [57.2%] female; 21 485 [21.5%] African American, 56 309 [53.8%] White), of whom 18 197 (2.0%) received IV acetaminophen, and 287 504 (34.0%) received IV opioids. After applying exclusion criteria, among patients who received IV acetaminophen, 1739 (10.8%) received IV acetaminophen prior to IV opioids within a median (IQR) treatment time of 1.5 (0.02-7.3) hours. After propensity score matching produced comparable groups in the control and intervention groups (with 839 patients in each group), the multivariable model estimated a 15.5% shorter duration of IV opioid use in the intervention group, with an absolute IV opioid reduction of 7.5 hours (95% CI, 0.7-15.8 hours).

Conclusions and Relevance

In this comparative effectiveness study, IV acetaminophen administered prior to IV opioids was associated with a reduction in IV opioid duration by 15.5%. Multimodal pain regimens that use IV acetaminophen prior to IV opioids could reduce IV opioid duration.

Paeonol Derivatives and Pharmacological Activities: A Review of Recent Progress

Paeonol, 2-hydroxy-4-methoxy acetophenone, is one of the main active ingredients of traditional Chinese medicine such as Cynanchum paniculatum, Paeonia suffruticosa Andr and Paeonia lactiflora Pall. Modern medical research has shown that paeonol has a wide range of pharmacological activities. In recent years, a large number of studies have been carried out on the structure modification of paeonol and the mechanism of action of paeonol derivatives has been studied. Some paeonol derivatives exhibit good pharmacological activities in terms of antibacterial, anti-inflammatory, antipyretic analgesic, antioxidant and other pharmacological effects. Herein, the research progress on paeonol derivatives and their pharmacological activities were systematically reviewed.

Sedation, Analgesia, and Neuromuscular Blockade: An Assessment of Practices From 2009 to 2016 in a National Sample of 66,443 Pediatric Patients Cared for in the ICU

OBJECTIVES

To describe the pharmaceutical management of sedation, analgesia, and neuromuscular blockade medications administered to children in ICUs.

DESIGN

A retrospective analysis using data extracted from the national database Health Facts.

SETTING

One hundred sixty-one ICUs in the United States with pediatric admissions.

PATIENTS

Children in ICUs receiving medications from 2009 to 2016.

EXPOSURE/INTERVENTION

Frequency and duration of administration of sedation, analgesia, and neuromuscular blockade medications.

MEASUREMENTS AND MAIN RESULTS

Of 66,443 patients with a median age of 1.3 years (interquartile range, 0-14.5), 63.3% (n = 42,070) received nonopioid analgesic, opioid analgesic, sedative, and/or neuromuscular blockade medications consisting of 83 different agents. Opioid and nonopioid analgesics were dispensed to 58.4% (n = 38,776), of which nonopioid analgesics were prescribed to 67.4% (n = 26,149). Median duration of opioid analgesic administration was 32 hours (interquartile range, 7-92). Sedatives were dispensed to 39.8% (n = 26,441) for a median duration of 23 hours (interquartile range, 3-84), of which benzodiazepines were most common (73.4%; n = 19,426). Neuromuscular-blocking agents were dispensed to 17.3% (n = 11,517) for a median duration of 2 hours (interquartile range, 1-15). Younger age was associated with longer durations in all medication classes. A greater proportion of operative patients received these medication classes for a longer duration than nonoperative patients. A greater proportion of patients with musculoskeletal and hematologic/oncologic diseases received these medication classes.

CONCLUSIONS

Analgesic, sedative, and neuromuscular-blocking medications were prescribed to 63.3% of children in ICUs. The durations of opioid analgesic and sedative medication administration found in this study can be associated with known complications, including tolerance and withdrawal. Several medications dispensed to pediatric patients in this analysis are in conflict with Food and Drug Administration warnings, suggesting that there is potential risk in current sedation and analgesia practice that could be reduced with practice changes to improve efficacy and minimize risks.

Chloral hydrate enteral infusion for sedation in ventilated children: the CHOSEN pilot study

Background

We aimed to test a novel method of delivery of chloral hydrate (CH) sedation in ventilated critically ill young children.

Methods

Children < 12 years old, within 72 hours of admission, who were ventilated, receiving enteral tube-feeds, with intermittent CH ordered were enrolled after signed consent. Patients received a CH loading-dose of 10 mg/kg enterally, then a syringe-pump enteral infusion at 5 mg/kg/hour, increasing to a maximum of 9 mg/kg/hour. Cases were compared to historical controls matched for age group and Pediatric Risk of Mortality score (PRISM) category, using Fisher’s exact test and the t test. The primary outcome was feasibility, defined as the use of an enteral CH continuous infusion without discontinuation attributable to a pre-specified potential harm.

Results

There were 21 patients enrolled, at age 11.4 (12.1) months, with bronchiolitis in 10 (48%), a mean Pediatric Logistic Organ Dysfunction (PELOD) score of 6.2 (5.2), and having received enteral CH continuous infusion for 4.5 (2.2) days. Infusion of CH was feasible in 20/21 (95%; 95% CI 76–99%) patients, with one (5%) adverse event of duodenal ulcer perforation on day 3 in a patient with croup receiving regular ibuprofen and dexamethasone. The CH infusion dose (mg/kg/h) on day 2 (n = 20) was 8.9 (IQR 5.9, 9), and on day 4 (n = 11) was 8.8 (IQR 7, 9). Days to titration of adequate sedation (defined as ≤ 3 PRN doses/shift) was 1 (IQR 0.5, 2.5), and hours to awakening for extubation was 5 (IQR 2, 9). Cases (versus controls) had less positive fluid balance at 48 h (-2 (45) vs. 26 (46) ml/kg, p = 0.051), and a decrease in number of PRN sedation doses from 12 h pre to 12 hours post starting CH (4.7 (3.3) to 2.6 (2.8), p = 0.009 versus 2.9 (3.9) to 3.4 (5), p = 0.74). There were no statistically significant differences between cases and controls in inotrope scores, signs or treatment of withdrawal, or PICU days.

Conclusions

Delivering CH by continuous enteral infusion is feasible, effective, and may be associated with less positive fluid balance. Whether there is a risk of duodenal perforation requires further study.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1879-7) contains supplementary material, which is available to authorized users.

Case Study of High-Dose Ketamine for Treatment of Complex Regional Pain Syndrome in the Pediatric Intensive Care Unit

Complex regional pain syndrome (CRPS) is a life-altering and debilitating chronic pain condition. The authors are presenting a case study of a female who received high-dose ketamine for the management of her CRPS. The innovative treatment lies not only within the pharmacologic management of her pain, but also in the fact that she was the first patient to be admitted to our pediatric intensive care unit solely for pain control. The primary component of the pharmacotherapy treatment strategy plan was escalating-dose ketamine infusion via patient-controlled-analgesia approved by the pharmacy and therapeutics committee guided therapy for this patient. The expertise of advanced practice nurses blended exquisitely to ensure patient and family-centered care and the coordination of care across the illness trajectory. The patient experienced positive outcomes.

Sedation and Analgesia in Pediatric Cardiac Critical Care

OBJECTIVES

This review will focus on the pharmacokinetics (with an emphasis on the context-sensitive half-time), pharmacodynamics, and hemodynamic characteristics of the most commonly used sedative/hypnotic, analgesic, and IV anesthetics used in cardiac intensive care. In addition, the assessment of pain and agitation and withdrawal will be reviewed.

DATA SOURCE

MEDLINE, PubMed.

CONCLUSIONS

Children in the cardiac ICU often require one or more components of general anesthesia: analgesia, amnesia (sedation and hypnosis), and muscle relaxation to facilitate mechanical ventilation, to manage postoperative pain, to perform necessary procedures, and to alleviate fear and anxiety. Furthermore, these same children are often vulnerable to hemodynamic instability due to unique underlying physiologic vulnerabilities. An assessment of hemodynamic goals, postoperative procedures to be performed, physiologic vulnerabilities, and the intended duration of mechanical ventilation should be made. Based on this assessment, the optimal selection of sedatives, analgesics, and if necessary, muscle relaxants can then be made.

Pediatric Cardiac Intensive Care Society 2014 Consensus Statement: Pharmacotherapies in Cardiac Critical Care: Sedation, Analgesia and Muscle Relaxant

OBJECTIVE

This article reviews pharmacotherapies currently available to manage sedation, analgesia, and neuromuscular blockade for pediatric cardiac critical patients.

DATA SOURCES

The knowledge base of an expert panel of pharmacists, cardiac anesthesiologists, and a cardiac critical care physician involved in the care of pediatric cardiac critical patients was combined with a comprehensive search of the medical literature to generate the data source.

STUDY SELECTION

The panel examined all studies relevant to management of sedation, analgesia, and neuromuscular blockade in pediatric cardiac critical patients.

DATA EXTRACTION

Each member of the panel was assigned a specific subset of the studies relevant to their particular area of expertise (pharmacokinetics, pharmacodynamics, and clinical care) to review and analyze.

DATA SYNTHESIS

The panel members each crafted a comprehensive summary of the literature relevant to their area of expertise. The panel, as a whole, then collaborated to cohesively summarize all the available, relevant literature.

CONCLUSIONS

In the cardiac ICU, management of the cardiac patient requires an individualized sedative and analgesic strategy that maintains hemodynamic stability. Multiple pharmacological therapies exist to achieve these goals and should be selected based on the patient's underlying physiology, hemodynamic vulnerabilities, desired level of sedation and analgesia, and the projected short- or long-term recovery trajectory.

Practice guidelines for sedation and analgesia management of critically ill children: a pilot study evaluating guideline impact and feasibility in the PICU

AIMS

The aim of this study was to develop and implement guidelines for sedation and analgesia management in the paediatric intensive care unit (PICU) and evaluate the impact, feasibility and acceptability of these as part of a programme of research in this area and as a prelude to future trial work.

METHOD

This pilot study used a pre-post design using a historical control.

SETTING

Two PICUs at different hospitals in an Australian metropolitan city.

PARTICIPANTS

Patients admitted to the PICU and ventilated for ≥24 h, aged more than 1 month and not admitted for seizure management or terminal care.

INTERVENTION

Guidelines for sedation and analgesia management for critically ill children including algorithm and assessment tools.

OUTCOME VARIABLES

In addition to key outcome variables (ventilation time, medication dose and duration, length of stay), feasibility outcomes data (recruitment, data collection, safety) were evaluated. Guideline adherence was assessed through chart audit and staff were surveyed about merit and the use of guidelines.

RESULTS

The guidelines were trialled for a total of 12 months on 63 patients and variables compared with the historical control group (n=75). Analysis revealed differences in median Morphine infusion duration between groups (pretest 3.63 days (87 h) vs post-test 2.83 days (68 h), p=0.05) and maximum doses (pretest 120 μg/kg/h vs post-test 97.5 μg/kg/h) with no apparent change to ventilation duration. Chart audit revealed varied use of tools, but staff were positive about the guidelines and their use in practice.

CONCLUSIONS

The sedation guidelines impacted on the duration and dosage of agents without any apparent impact on ventilation duration or length of stay. Furthermore, the guidelines appeared to be feasible and acceptable in clinical practice. The results of the study have laid the foundation for follow-up studies in withdrawal from sedation, point prevalence and longitudinal studies of sedation practices as well as drug trial work.

High doses of benzodiazepine predict analgesic and sedative drug withdrawal syndrome in paediatric intensive care patients

AIM

Critically ill children can develop withdrawal syndrome after prolonged analgesia and sedation in a paediatric intensive care unit (PICU), when treatment is stopped abruptly or reduced quickly. The aim of this study was to evaluate the incidence of withdrawal syndrome in patients after three or more days of analgesic or sedative drug therapy, using a validated scale. We also analysed the association between withdrawal syndrome and the patients' outcome and factors related to analgesia and sedation treatment.

METHODS

This prospective observational study analysed 89 periods of weaning from analgesia and sedation in 60 children between October 2010 and October 2011. Of these, 65% were less than six months old and 45% were admitted to the PICU after heart surgery. Withdrawal syndrome was assessed using the Withdrawal Assessment Tool-1 (WAT-1) scale.

RESULTS

The incidence of withdrawal syndrome was 37%, and the only variable that predicted its presence was the highest administered dose of benzodiazepine. The duration of weaning, Sophia Observational Withdrawal Symptom scale score and nurse judgment were also associated with positive WAT-1 scores.

CONCLUSION

Withdrawal syndrome should be considered after three or more days of analgesic or sedative treatment. A high dose of benzodiazepine increases the risk of developing withdrawal symptoms.

Assessing circadian rhythms during prolonged midazolam infusion in the pediatric intensive care unit (PICU) children

BACKGROUND

This study evaluates possible circadian rhythms during prolonged midazolam infusion in 27 pediatric intensive care unit (PICU) children under mechanical ventilation.

METHODS

Blood samples for midazolam and 1-OH-midazolam assay were collected throughout the infusion at different times of the day. The blood pressure, heart rate and body temperature were recorded every hour for the rhythms analysis. Population nonlinear mixed-effect modeling with NONMEM was used for data analysis.

RESULTS

A two-compartment model for midazolam pharmacokinetics and a one-compartment model for midazolam metabolite adequately described the data. The 24 h profiles of all monitored physiological parameters were greatly disturbed/abolished in comparison with the well-known 24 h rhythmic patterns in healthy subjects. There was no significant circadian rhythm detected with respect to midazolam pharmacokinetics, its active metabolite pharmacokinetics and all monitored parameters.

CONCLUSIONS

We concluded that the light-dark cycle did not influence midazolam pharmacokinetics in intensive care units children. Also, endogenous rhythms in critically ill and sedated children are severely disturbed and desynchronized. Our results confirmed that it is necessary to adjust the dose of midazolam to the patient's body weight. The low value of midazolam clearances observed in our study was probably caused by mechanical ventilation, which was shown to decrease the cardiac output.

A predictive pharmacokinetic/pharmacodynamic model of fentanyl for analgesia/sedation in neonates based on a semi-physiologic approach

BACKGROUND AND OBJECTIVES

Fentanyl is a synthetic opioid commonly used as an anesthetic and also increasingly popular as a sedative agent in neonates. Initial dosage regimens in this population are often empirically derived from adults on a body weight basis. However, ontogenic maturation processes related to drug disposition are not necessarily always body weight correlates. We developed a predictive pharmacokinetic/pharmacodynamic model that includes growth and maturation physiologic changes for fentanyl in neonatal care.

METHODS

Key pharmacokinetic variables and principles (protein binding, clearance, distribution) as related to fentanyl pharmacokinetic/pharmacodynamic behavior in adults (tricompartmental model) and to neonatal physiologic data (organ weights and blood flows, body composition, renal and hepatic function, etc.) were used to guide the building of a semi-physiologic ontogenic model. The model applies to a normal-term neonate without any other intervention. Then, extension to a pharmacokinetic/pharmacodynamic link model for fentanyl was made. The final model was evaluated by predicting the time course of plasma concentrations and the effect of a standard regimen of 10.5 μg/kg over a 1-h period followed by 1.5 μg/kg/h for 48 h.

RESULTS

Hepatic clearance was linked to ontogeny of unbound fraction and of α1-acid glycoprotein. All parameters were reduced in the neonate compared to adults but in a differing proportion due to qualitative changes in physiology that are analyzed and accounted for. Systemic clearance (CLS), volume of the central compartment (V1) and steady-state volume of distribution predicted by the model were 0.028 L/min, 1.26 L, and 22.04 L, respectively. Weight-corrected parameters generally decreased in adults compared with neonates, but differentially, e.g., CLS = 0.0093 versus 0.0088 L/min/kg, while V1 = 0.42 versus 0.18 L/kg (neonates vs. adults). Under such complexity a pharmacokinetic/pharmacodynamic model is the appropriate method for rational efficacy targeting. Fentanyl pharmacodynamics in neonates were considered to be similar to those in adults except for the equilibrium rate constant, which was also scaled on an ontogenic basis. The model adequately predicted the reported mean expected concentration-time profiles for the standard regimen.

CONCLUSIONS

Integrated pharmacokinetic/pharmacodynamic modeling showed that the usually prescribed dosage regimens of fentanyl in neonates may not always provide the optimum degree of sedation. The model could be used in optimal design of clinical trials for this vulnerable population. Prospective clinical testing is the reasonable next step.

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.

Pediatric illness severity measures predict delirium in a pediatric intensive care unit

CONTEXT

Delirium in children is a serious but understudied neuropsychiatric disorder. So there is little to guide the clinician in terms of identifying those at risk.

OBJECTIVE

To study, in a pediatric intensive care unit (PICU), the predictive power of widely used generic pediatric mortality scoring systems in relation to the occurrence of pediatric delirium (PD).

DESIGN AND METHODS

Four-year prospective observational study, 2002-2005. Predictors used were the Pediatric Index of Mortality (PIM) and Pediatric Risk of Mortality (PRISM II).

SETTING

A tertiary 8-bed PICU in The Netherlands.

PATIENTS

877 critically ill children who were acutely, nonelectively, and consecutively admitted.

MAIN OUTCOME MEASURE

Pediatric delirium.

MAIN RESULTS

Out of 877 children with mean age 4.4 yrs, 40 were diagnosed with PD (Cumulative incidence: 4.5%), 85% of whom (versus 40% with nondelirium) were mechanically ventilated. The area under the curve was 0.74 for PRISM II and 0.71 for the PIM, with optimal cut-off points at the 60th centile (PRISM: sensitivity: 76%; specificity: 62%; PIM: sensitivity: 82%; specificity: 62%). A PRISM II or PIM score above the 60th centile was strongly associated with later PD in terms of relative risk (PRISM II: risk ratio = 4.9; 95% confidence interval: 2.3-10.1; PIM: RR = 6.7; 95% confidence interval: 3.0-15.0). Given the low incidence of PD, values for positive predictive value were lower (PRISM II: 8.3%; PIM: 8.9%, rising to, respectively, 10.1% and 10.6% in mechanically ventilated patients) and values for negative predictive value were higher (PRISM II: 98.3%; PIM: 98.7%).

LIMITATIONS

Given the relatively low incidence of delirium, a low detection rate biased toward the most severe cases cannot be excluded.

CONCLUSIONS

Given the fact that PIM and PRISM II are widely used mortality scoring instruments, prospective associations with PD suggest additional value for ruling in, or out, patients at risk of PD.

Clinical uses of dexmedetomidine in pediatric patients

Dexmedetomidine is being used off-label as an adjunctive agent for sedation and analgesia in pediatric patients in the critical care unit and for sedation during non-invasive procedures in radiology. It also has a potential role as part of anesthesia care to prevent emergence delirium and postanesthesia shivering. Dexmedetomidine is currently approved by the US FDA for sedation only in adults undergoing mechanical ventilation for <24 hours. Pediatric experiences in the literature are in the form of small studies and case reports. In patients sedated for mechanical ventilation and/or opioid/benzodiazepine withdrawal, the loading dose ranged from 0.5 to 1 microg/kg and was usually administered over 10 minutes, although not all patients received loading doses. This patient group also received a continuous infusion at rates ranging from 0.2 to 2 microg/kg/h, with higher rates used in burn patients and those with withdrawal following > or =24 hours of opioid/benzodiazepine infusion. The dexmedetomidine dosage used for anesthesia and sedation during non-invasive procedures, such as radiologic studies, ranged from a loading dose of 1-2 microg/kg followed by a continuous infusion at 0.5-1.14 microg/kg/h, with most patients spontaneously breathing. For invasive procedures, such as awake craniotomy or cardiac catheterization, dosage ranged from a loading dose of 0.15 to 1 microg/kg followed by a continuous infusion at 0.1-2 microg/kg/h. Adverse hemodynamic and respiratory effects were minimal; the agent was well tolerated in most patients. The efficacy of dexmedetomidine varied depending on the clinical situation: efficacy was greatest during non-invasive procedures, such as magnetic resonance imaging (MRI), and lowest during invasive procedures, such as cardiac catheterization. Dexmedetomidine may be useful in pediatric patients for sedation in a variety of clinical situations. The literature suggests potential use of dexmedetomidine as an adjunctive agent to other sedatives during mechanical ventilation and opioid/benzodiazepine withdrawal. In addition, because of its minimal respiratory effects, dexmedetomidine has also been used as a single agent for sedation during non-invasive procedures such as MRI. However, additional studies in pediatric patients are warranted to further evaluate its safety and efficacy in all age ranges.

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.

Pediatric delirium in critical illness: phenomenology, clinical correlates and treatment response in 40 cases in the pediatric intensive care unit

Objective

To study the phenomenology, clinical correlates, and response to treatment of delirium in critically ill children in the pediatric intensive care unit (PICU).

Design, setting and patients

Descriptive study of a cohort of child psychiatric consultations from a tertiary PICU between January 2002 and December 2005. Demographic data, clinical presentation, and response to treatment of children subsequently diagnosed with delirium were analyzed.

Results

Out of 877 admissions (age distribution 0–18 years) arose 61 requests for psychiatric assessment. Of the 61 children, 40 (15 girls and 25 boys) were diagnosed with delirium (cumulative incidence 5%; mean age 7.6 years). Age-specific incidence rates varied from 3% (0–3 years) to 19% (16–18 years). In addition to the classical hypoactive and hyperactive presentations, a third presentation was apparent, characterized mainly by anxiety, with a higher prevalence in boys. All but 2 of the 40 children received antipsychotic medication: 27 (68%) haloperidol, 10 (25%) risperidone, and 1 both in succession. Two children treated with haloperidol experienced an acute torticollis as side effect. All children made a complete recovery from the delirium; five, however, died of their underlying disease.

Conclusion

The rate of delirium in critically ill children on a PICU is not negligible, yet prospective studies of the phenomenology, risk factors and treatment of childhood delirium are very rare. Once pediatric delirium has been recognized, it generally responds well to treatment.

Age is of influence on midazolam requirements in a paediatric intensive care unit

AIM

To test that age is of influence on midazolam requirements during prolonged mechanical ventilation in critically ill children.

METHODS

Retrospective observational study of children (28 days-18 year) admitted between January 1st 2002 and January 1st 2005 who needed controlled mechanical ventilation for 5 days and initial sedation with midazolam were included. Exclusion criteria were psychomotor retardation, therapeutic use of midazolam, ventilator weaning within 5 days, kidney or liver failure.

RESULTS

A total of 1186 children were admitted, of which 58 children were included. The children were divided into three age groups: 28 days-1 year (n = 28), 1-4 years (n = 16) and older than 4 years (n = 14). Within 2 days the children age 1-4 years received the maximum midazolam dosage (0.3 mg/kg/h). In addition, the mean total dose of midazolam was higher at all days for this age group. At day 5 none of the children between 1 and 4 years could be sedated with midazolam alone.

CONCLUSIONS

Our data showed that children between 1 and 4 years needed higher doses of midazolam as compared to children who were younger and older. Furthermore, we observed that midazolam alone is a poor sedative for all age groups. The influence of and mechanisms for possible age related effects on midazolam requirements remain to be elucidated, as well as the position of midazolam as a first line drug for PICU sedation.

Postoperative Sedation and Analgesia After Pediatric Liver Transplantation

The goal of sedation in the pediatric intensive care unit (PICU) is to produce a calm and comfortable child, free from pain and discomfort. Children receiving liver transplantation need analgesics to control pain from surgical incisions, drains, vascular access, or endotracheal suctioning. Sedatives are used to facilitate the delivery of nursing care, to prevent self-extubation, and to facilitate mechanical ventilation. Optimal sedation produces a state in which the patient is somnolent, responsive to the environment but untroubled by it, and with no excessive movements. A common problem in the PICU is the fluctuation in the delivery of sedatives and analgesics depending on the health care providers and on a breakdown in communication between physicians and nurses to define end points for pharmacological therapy. This variability more often leads to oversedation rather than undersedation. Oversedation delays extubation, promotes ventilator-associated pneumonia, and increases the risk of reintubation. The use of written sedation policies to guide practice at the bedside reduces the length of time for which patients require mechanical ventilation and the length of PICU stay. Protocols for drug administration practices increase patient safety during mechanical ventilation, promote nursing autonomy, and facilitate communication between nurses and physicians as well as between nurses.

Adverse responses: sedation, analgesia and neuromuscular blocking agents in critically ill children

Advanced practice nurses (APNs) prescribe sedation, analgesia, and neuromuscular blocking agents in the management of critically ill children. Although most children are unscathed from the use of the medications, some suffer adverse responses. This article elucidates adverse responses to these medications for the APN, including withdrawal syndrome, muscle weakness, decreased gastric motility, corneal abrasions, and costs associated with these morbidities.

Differential Effects of MK801 and Lorazepam on Heart Rate Variability in Adolescent Rhesus Monkeys (Macaca Mulatta)

Previous research shows that ketamine significantly alters cardiac signal regulation in rhesus monkeys, however relatively little is known about the mechanism for this effect. In the study reported here the relative contributions of NMDA receptor activation on cardiac signal dynamics were determined by administering a specific NMDA antagonist, MK801, to rhesus monkeys. The general effects of sedation were assessed by measuring cardiac response to lorazepam, a sedative drug without direct NMDA receptor activity. Electrocardiographic signal dynamics were examined before and after I.V. administration of either MK801 (0.16 mg/kg) or lorazepam (0.48 mg/kg). Inter-beat interval time series data were analyzed in the frequency domain after Fourier transform, and a nonlinear measure of autocorrelation, the Hurst exponent (H), was derived. After MK801 administration, log [HF /Total power] increased post-infusion (M = 1.11, SD = 0.45) compared with pre-infusion values [M = -0.19, SD = 0.32, F(1,4) = 19.49, P = 0.01] while H decreased, mean pre versus post 0.52+/-S.D. 0.10 versus 0.01+/- 0.05, P = 0.0002. Lorazepam administration did not significantly alter heart rate variability measures obtained in the frequency or nonlinear domains. To our knowledge, this is the first study that has defined the effects of peripherally administered MK801 on cardiovascular dynamics in primates and establishes that peripheral administration of NMDA antagonists result in large increases the high-frequency components of cardiac rhythm and increased heart rate variability compatible with MK801-associated increases in parasympathetic outflow.

Propofol 6% as sedative in children under 2 years of age following major craniofacial surgery

BACKGROUND

After alarming reports concerning deaths after sedation with propofol, infusion of this drug was contraindicated by the US Food and Drug Administration in children <18 yr receiving intensive care. We describe our experiences with propofol 6%, a new formula, during postoperative sedation in non-ventilated children following craniofacial surgery.

METHODS

In a prospective cohort study, children admitted to the paediatric surgical intensive care unit following major craniofacial surgery were randomly allocated to sedation with propofol 6% or midazolam, if judged necessary on the basis of a COMFORT behaviour score. Exclusion criteria were respiratory infection, allergy for proteins, propofol or midazolam, hypertriglyceridaemia, familial hypercholesterolaemia or epilepsy. We assessed the safety of propofol 6% with triglycerides (TG) and creatine phosphokinase (CPK) levels, blood gases and physiological parameters. Efficacy was assessed using the COMFORT behaviour scale, Visual Analogue Scale and Bispectral Index monitor.

RESULTS

Twenty-two children were treated with propofol 6%, 23 were treated with midazolam and 10 other children did not need sedation. The median age was 10 (IQR 3-17) months in all groups. Median duration of infusion was 11 (range 6-18) h for propofol 6% and 14 (range 5-17) h for midazolam. TG levels remained normal and no metabolic acidosis or adverse events were observed during propofol or midazolam infusion. Four patients had increased CPK levels.

CONCLUSION

We did not encounter any problems using propofol 6% as a sedative in children with a median age of 10 (IQR 3-17) months, with dosages <4 mg kg(-1) h(-1) during a median period of 11 (range 6-18) h.

Short-term propofol infusion as an adjunct to extubation in burned children

Children who require intubation as a component of their burn management generally need heavy sedation, usually with a combination of opiate and benzodiazepine infusions with a target sensorium of light sleep. When extubation approaches, the need for sedation to prevent uncontrolled extubation can conflict with the desire to lighten sedation enough to ensure that airway protective reflexes are strong. The several hours' half-life of these medications can make this period of weaning challenging. Therefore, the hours preceding extubation are among the most difficult in which to ensure safe adequate sedation. The pharmacokinetics of propofol allow for the rapid emergence of a patient from deep sedation. We have had success with an extubation strategy using short-term propofol infusions in critically ill children. In this work, children were maintained on morphine and midazolam infusions per our unit protocol, escalating doses as required to maintain comfort. Approximately 8 hours before planned extubation, these infusions were decreased by approximately half and propofol infusion added to maintain a state of light sleep. Extubation was planned approximately 8 hours later to allow ample time for the chronically infused opiates and benzodiazepines to be metabolized down to the new steady-state level. Thirty minutes before planned extubation, propofol was stopped while morphine and midazolam infusions were maintained at the reduced level. When the children awakened from the propofol-induced state of light sleep, they were extubated while the reduced infusions of morphine and midazolam were maintained. These were subsequently weaned slowly, depending on the child's need for ongoing pain and anxiety medication, per our unit protocol to minimize the incidence of withdrawal symptoms. Data are shown in the text as mean +/- standard deviation. These 11 children (eight boys and three girls) had an average age of 6.6 +/- 5.6 years (range, 1.2-13 years), average weight of 36.9 +/- 28.7 kg (range, 9.3-95 kg), and burn size of 43 +/- 21.4% (range, 10-85%). Three children had sustained scald burns and eight had flame injuries with associated inhalation injury. They had been intubated for an average of 12.7 +/- 10.9 (range, 2-33 days). Morphine infusions immediately before the initiation of propofol averaged 0.26 +/- 0.31 mg/kg/hour (range, 0.04-1.29 mg/kg/hr) and midazolam averaged 0.15 +/- 0.16 mg/kg/hr (range, 0.06-0.65 mg/kg/hr). Morphine infusions after beginning propofol and at extubation averaged 0.16 +/- 0.16 (range, 0.04-0.65 mg/kg/hr) and midazolam averaged 0.09 +/- 0.08 mg/kg/hr (range, 0.02-0.32 mg/kg/hr). Propofol doses after initial titration during the first hour of infusion averaged 3.6 +/- 2.9 mg/kg/hr (range, 0.4-8.1 mg/kg/hr). Nine of the 11 children (82%) were successfully extubated on the first attempt. Two required reintubation for postextubation stridor 2 to 6 hours after extubation but were successfully extubated the next day after a short course of steroids, again using the same propofol technique. All were awake at extubation and went on to survive. Morphine and midazolam infusions were gradually weaned, and there were no withdrawal symptoms noted. Although prolonged (days) infusions of propofol have been associated with adverse cardiovascular complications in critically ill young children and should probably be avoided, short-term (in hours) use of the drug can facilitate smooth extubation.

Procedural sedation for children with special health care needs

Children with special health care needs represent a growing percentage of pediatric patients treated in all emergency departments. Substantial literature exists concerning the medical treatment of these patients, but there is little written describing the management of procedural sedation or analgesia in this population. This article examines the unique anatomic and physiologic implications of procedural sedation or analgesia management in children with special health care needs.