Pediatric Sedation and Analgesia
The relief of pain and anxiety becomes one of the most important aspects of care in the critically ill child. Often, infusions are employed as a means of delivering a continuous level of patient analgesia. The ventilated pediatric patient is a unique challenge; endotracheal tube discomfort, ventilator asynchrony, and severity of lung disease are important factors necessitating the use of sedative and anxiolytic agents. In this section, we review common approaches to sedation and analgesia of the critically ill child and long-term side effects, with primary focus on agents used in the child who is mechanically ventilated.
Despite their benefit, continuous infusions of sedatives and analgesics have been shown to be independent predictors of prolonged mechanical ventilation and increased length of stay in the PICU. Additionally, consequences of these infusions include dependence and associated risks of acute withdrawal, delirium, and potential long-term effects on the developing brain.
Practice varies in the approach to sedation and analgesia in children, because few studies in children are available to guide appropriate selection of specific agents. Some studies in children have suggested that the use of objective assessments to guide appropriate levels of sedation and analgesia, and protocols to escalate dosages and wean from infusions, reduce the number of days of exposure to agents. However, the largest trial to date failed to show decreased duration of mechanical ventilation in intubated patients who were treated with a sedation protocol.
Several objective tools have been developed to guide the appropriate level of sedation of PICU patients based on clinical scenario. The Richmond Agitation–Sedation Scale and the State Behavioral Scale are two such tools.
|Richmond Agitation and Sedation Scale (RASS)
||Violent, immediate danger to self and staff
||Pulls at lines or tubes, aggressive
||Frequent, nonpurposeful movements, fights ventilator
||Anxious, apprehensive, but movements not aggressive or vigorous
||Alert and calm
||Not fully alert, but has sustained awakening to voice (eye opening and eye contact ≥10 seconds)
||Briefly awakens to voice (eye opening and eye contact <10 seconds)
||Movement or eye opening to voice (but no eye contact)
||No response to voice, but movement or eye opening to physical stimulation
||No response to voice or physical stimulation
Benzodiazepines have historically been the mainstay of sedation in the PICU, administered as either intermittent doses or a continuous infusion. The most common agent used is midazolam. Major side effects of benzodiazepines include respiratory depression, hypotension, and delirium. In select patients, intermittent doses of benzodiazepines may help reduce total benzodiazepine exposure.
Dexmedetomidine is an alpha-2-adrenergic agonist that can be used for sedation of critically ill children. It does not cause respiratory depression but typically does not provide levels of deep sedation. Major side effects are bradycardia, hypotension, and hypertension at higher doses.
Propofol is an anesthetic drug that is commonly used in operative procedures for sedation. Pediatric patients are at risk for propofol-related infusion syndrome (PRIS), which can cause irreversible metabolic derangements and bradycardia. Risk factors for PRIS include young age, higher doses of propofol infusion, and simultaneous treatment with catecholamines, although the syndrome has been described in patients without these characteristics. Given this risk, propofol is used cautiously and is generally limited to use for less than 24 hours.
Pediatric patients requiring continuous analgesia are typically managed with opioid infusions. Common agents include morphine and fentanyl. Major side effects include respiratory depression, tolerance, and dependence. Additionally, intermittent dosing of nonopioid analgesics is often also used, including acetaminophen and NSAIDs.
Discontinuation of Infusion Therapy
As children recover from their illness or need for mechanical ventilation, care must be taken to prevent withdrawal from opioid and benzodiazepine dependence. In general, patients who are on infusions for ≥5 days are at risk of withdrawal symptoms, but children who have received shorter duration of therapy can also be affected. Many strategies have been employed to prevent withdrawal, including slow weaning off of infusions and use of intermittent replacement therapy with intravenous or enteral equivalents of drugs including lorazepam, methadone, and clonidine. Children should be assessed for signs and symptoms of withdrawal, generally with an objective scoring tool, and treated with “rescue” doses of drugs to lessen discomfort if withdrawal were to occur. One such validated tool is the Withdrawal Assessment Tool (WAT-1), which assesses withdrawal-related symptoms such as gastrointestinal discomfort (diarrhea, loose stools, vomiting), tremors, sweating, yawning/sneezing, and muscle tone.
For more information on procedural sedation and analgesia and rapid-sequence induction for intubation, please see Common Procedures in the Pediatric Emergency Medicine rotation guide.