Sedation and analgesia in the PICU: many questions remain

Considerations for pediatric burn sedation and analgesia

Burn patients experience anxiety and pain in the course of their injury, treatment, and recovery. Hence, treatment of anxiety and pain is paramount after burn injury. Children, in particular, pose challenges in anxiety and pain management due to their unique physiologic, psychologic, and anatomic status. Burn injuries further complicate pain management and sedation as such injuries can have effects on medication response and elimination. Burn injuries further complicate pain management and sedation as such injuries can have effects on medication response and elimination. The purpose of this review is to describe the challenges associated with management of anxiety, pain, and sedation in burned children and to describe the different options for treatment of anxiety and pain in burned children.

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.

Sedation guidelines, protocols, and algorithms in PICUs: a systematic review

OBJECTIVE

To evaluate the impact of sedation guidelines, protocols, and algorithms on clinical outcomes in PICUs.

DATA SOURCES

CINAHL, Medline, EMBASE, Web of Science, and the Cochrane Database of Systematic Reviews,

STUDY SELECTION

: English-only publications from 1966 to December 2013, which included keywords "sedation," "guideline," "algorithm," "protocol," and "pediatric intensive care." We included all primary studies involving critically ill children on sedation guidelines, protocols, and algorithms and excluded those which focused mainly on diagnostic or procedural purposes.

DATA EXTRACTION

Two authors independently screened each article for inclusion. A standardized data extraction sheet was used to extract data from all included studies.

DATA SYNTHESIS

Among the 1,283 citations yielded from our search strategy, six observational studies were included in the final review. Due to the heterogeneity of the studies included, clinical outcomes were not combined into a meta-analysis. A descriptive account of the studies was formulated to characterize all included studies. The three outcomes of interest were clinical outcomes, patients' comfort and safety, and sedative use. We found an association between the use of sedation guidelines, protocols, and algorithms and reduced PICU length of stay, frequency of unplanned extubation, prevalence of patients experiencing drug withdrawal, total sedation duration, and doses. Overall, the quality of identified studies is low.

CONCLUSIONS

Despite widespread recommendation for the use of sedation guidelines, protocols, and algorithms in critically ill children, our systematic review revealed a paucity of high-quality evidence to guide this practice. More robust studies are urgently needed for this important aspect of PICU care.

Extubation during pediatric extracorporeal membrane oxygenation: a single-center experience

OBJECTIVES

Describe aspects of one center's experience extubating infants and children during extracorporeal membrane oxygenation.

DESIGN

Retrospective review of medical records.

SETTING

Seventy-one-bed critical care service (PICU and cardiovascular ICU) in a large urban tertiary children's hospital.

PATIENTS

Pediatric and neonatal patients supported on extracorporeal membrane oxygenation between 1996 and 2013 who were either not intubated or extubated greater than 24 hours during their extracorporeal membrane oxygenation course.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Sixteen of 511 patients on extracorporeal membrane oxygenation were extubated for at least 24 hours during their extracorporeal membrane oxygenation courses. Fourteen had respiratory failure and two had cardiac disease. Five patients died while on extracorporeal membrane oxygenation, but the cause of death was not related to complications associated with extubation. Extubated patients were supported a median of 19.7 days on extracorporeal membrane oxygenation, with a median extubation latency (time between cannulation and first extubation) of 6.2 days and a median extubation duration of 5.5 days. Mean time extubated was 43% of the total time on extracorporeal membrane oxygenation. Two patients were reintubated briefly or had a laryngeal mask airway placed for decannulation (n = 1). The remaining patients were extubated within 5 days of decannulation, weeks afterward (n = 2), transferred to outside facilities (n = 2), or died during extracorporeal membrane oxygenation support (n = 5). We also observed no complications directly attributable to extubation and spontaneous reaeration of consolidated lungs in acute respiratory distress syndrome in extubated patients on extracorporeal membrane oxygenation.

CONCLUSION

Extubation and discontinuation of mechanical ventilation appear feasible in patients requiring long-term extracorporeal membrane oxygenation. Emergency procedure planning may need to be modified in extubated patients on extracorporeal membrane oxygenation.

Feasibility of sedation and analgesia interruption following cannulation in neonates on extracorporeal membrane oxygenation

Purpose

In most extracorporeal membrane oxygenation (ECMO) centers patients are heavily sedated to prevent accidental decannulation and bleeding complications. In ventilated adults not on ECMO, daily sedation interruption protocols improve short- and long-term outcome. This study aims to evaluate safety and feasibility of sedation interruption following cannulation in neonates on ECMO.

Methods

Prospective observational study in 20 neonates (0.17–5.8 days of age) admitted for ECMO treatment. Midazolam (n = 20) and morphine (n = 18) infusions were discontinued within 30 min after cannulation. Pain and sedation were regularly assessed using COMFORT-B and visual analog scale (VAS) scores. Midazolam and/or morphine were restarted and titrated according to protocolized treatment algorithms.

Results

Median (interquartile range, IQR) time without any sedatives was 10.3 h (5.0–24.1 h). Median interruption duration for midazolam was 16.5 h (6.6–29.6 h), and for morphine was 11.2 h (6.7–39.4 h). During this period no accidental extubations, decannulations or bleeding complications occurred.

Conclusions

This is the first study to show that interruption of sedatives and analgesics following cannulation in neonates on ECMO is safe and feasible. Interruption times are 2–3 times longer than reported for adult ICU patients not on ECMO. Further trials are needed to substantiate these findings and evaluate short- and long-term outcomes.

Developmental neurotoxicity of sedatives and anesthetics: a concern for neonatal and pediatric critical care medicine?

OBJECTIVE

To evaluate the currently available evidence for the deleterious effects of sedatives and anesthetics on developing brain structure and neurocognitive function.

DESIGN

A computerized, bibliographic search of the literature regarding neurodegenerative effects of sedatives and anesthetics in the developing brain.

MEASUREMENTS AND MAIN RESULTS

A growing number of animal studies demonstrate widespread structural damage of the developing brain and long-lasting neurocognitive abnormalities after exposure to sedatives commonly used in neonatal and pediatric critical care medicine. These studies reveal a dose and exposure time dependence of neuronal cell death, characterize its molecular pathways, and suggest a potential early window of susceptibility in humans. Several clinical studies document neurologic abnormalities in neonatal intensive care unit graduates, usually attributed to comorbidities. Emerging human epidemiologic data, however, do not exclude prolonged or repetitive exposure to sedatives and anesthetics in early childhood as contributing factors to some of these abnormalities.

CONCLUSIONS

Neuronal cell death after neonatal exposure to sedatives and anesthetics has been clearly demonstrated in developing animal models. Although the relevance for human medicine remains speculative, the phenomenon's serious implications for public health necessitate further preclinical and clinical studies. Intensivists using sedatives and anesthetics in neonates and infants need to stay informed about this rapidly emerging field of research.

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.

Effect of low-dose naloxone infusion on fentanyl requirements in critically ill children

OBJECTIVE

Sedating critically ill patients often involves prolonged opioid infusions causing opioid tolerance. Naloxone has been hypothesized to limit opioid tolerance by decreasing adenylate cyclase/cyclic adenosine monophosphate activation. The study purpose was to investigate the effect of low-dose naloxone on the maximum cumulative daily fentanyl dose in critically ill children.

METHODS

We conducted a double-blinded, randomized, placebo-control trial from December 2002 through July 2004 in a university PICU. We enrolled 82 children age 1 day to 18 years requiring mechanical ventilation and fentanyl infusions anticipated to last for >4 days were eligible for enrollment. Those receiving additional oral analgesia or sedation, having a history of drug dependence or withdrawal, or having significant neurologic, renal, or hepatic disease were excluded. In addition to fentanyl infusions, patients received low-dose naloxone or placebo infusions. Medications were adjusted using the Modified Motor Activity Assessment Scale. Withdrawal was monitored using the Modified Narcotic Withdrawal Scale. Intervention was a low-dose naloxone infusion (0.25 microg/kg per hour) and the main outcome variable was the maximum cumulative daily fentanyl dose (micrograms per kilogram per day).

RESULTS

There was no difference in the maximum cumulative daily fentanyl dose between patients treated with naloxone (N = 37) or those receiving placebo (N = 35). Adjustment for the starting fentanyl dose also failed to reveal group differences. Total fentanyl dose received throughout the study in the naloxone group (360 microg/kg) versus placebo (223 microg/kg) was not statistically different. Placebo patients trended toward fewer rescue midazolam boluses (10.7 vs 17.8), lower total midazolam dose (11.6 mg/kg vs 23.9 mg/kg), and fewer rescue fentanyl boluses (18.5 vs 23.9).

CONCLUSIONS

We conclude that administration of low-dose naloxone (0.25 microg/kg per hour) does not decrease fentanyl requirements in critically ill, mechanically ventilated children.

Monitoring the anaesthetic depth in children - an update

PURPOSE OF REVIEW

There are several commercially available electroencephalogram-derived devices for monitoring anaesthesia depth. This article reviews all published studies describing their use in children; first assessing studies of performance in measuring anaesthesia depth in observational, physiological studies and then describing relevant outcome studies. There is also a brief discussion of why they might be useful, what physiological problems may arise and what the reader should be wary of in the methodology of these studies. The subject is approached from a clinical perspective.

RECENT FINDINGS

There are several physiological studies suggesting that for older children the bispectral index, entropy, Narcotrend index, cerebral state index and A-line ARX index all change with induction of anaesthesia, and have reasonable correlations with doses of anaesthetic agent. There is consistent evidence that the performances are substantially poorer in infants. Some of these devices have been demonstrated to reduce anaesthesia drug consumption and hasten recovery in older children.

SUMMARY

The bispectral index is the most widely studied, but at this stage there is no evidence to suggest any one device is substantially superior to any other. There may be a role emerging for their use in older children, but their use in infants cannot be supported.

Current United Kingdom sedation practice in pediatric intensive care

BACKGROUND

The aim of this study was to investigate the current practice of sedation, analgesia, and neuromuscular blockade in critically ill children on pediatric intensive care units (PICUs) in the UK and identify areas that merit further study.

METHODS

Data were gathered in a prospective observational study of 338 critically ill children in 20 UK PICUs.

RESULTS

There is considerable variation in clinical practice. A total of 24 different sedative and analgesic agents were used during the study. The most commonly used sedative and analgesic agents were midazolam and morphine. Four different neuromuscular blockers (NMBs) were used, most commonly vecuronium. There were differences in treatment between cardiac and noncardiac children, but there were a greater number of infants and neonates in the cardiac group. NMBs were used in 30% of mechanically ventilated patients. Withdrawal symptoms were reported in 13% of ventilated patients, relatively early in their stay; weaning sedative agents ('tapering') was apparently of no benefit. The use of clonidine in this setting was noted. Physical restraints were used in 7.4%. Propofol was used but in only 2.6% of patients, all over the age of 4 years, and not exceeding 2 mgxkg(-1)xh(-1). No side effects attributable to 'propofol syndrome' were noted.

CONCLUSIONS

There is considerable heterogeneity of sedation techniques. NMBs are used in a large portion of this population. Withdrawal symptoms were associated with higher doses of sedation and greater lengths of stay and were not ameliorated by withdrawing sedation gradually ('tapering').

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.