ET, Endotracheal; IM, intramuscular; IV, intravenous; PO, oral; SC, subcutaneous. *See Table 45-4 for causes of methemoglobinemia.
An acutely ill pediatric patient may have pain, discomfort, andanxiety resulting from injury, surgery, and invasive procedures(intubation, bone marrow aspiration, venous access placement)or during life-sustaining mechanical ventilation. Clear goalsshould be identified to allow provision of optimal analgesia orsedation without compromising the physiologic status of thepatient. Anxiolysis, cooperation, amnesia, immobility, and lackof awareness all are goals of sedation and can be accomplishedwith various drugs (Table 46-1). Many of these goals can beachieved with behavioral techniques (preprocedural teaching),but sedation is often a necessary adjunct for painful procedures.Pain may be expressed by verbal or visible discomfort, crying,agitation, tachycardia, hypertension, and tachypnea. A varietyof scales have been developed in an attempt to quantify painand allow more directed therapy. Few of these scales are wellvalidated, especially in populations of acutely ill children withphysiologic derangements secondary to the underlying pathology. Pain caused by procedural interventions should always betreated with analgesics in addition to sedation (Table 46-2).
A medical evaluation must be performed for any patient receiving procedural sedation to identify underlying medical conditions that may affect the choice of sedative agents. Specific attention must be paid to assessment of the airway (for ability to maintain a patent airway) and respiratory system (asthma, recent respiratory illness, loose teeth), cardiovascular status (especially adequacy of volume status), factors affecting drug metabolism (renal or liver disease), and risk of aspiration (adequate nothing-by-mouth status, gastroesophageal reflux). During the administration of procedural sedation, assessment of status must include monitoring of oxygen saturation, heart rate, and respiratory rate, as well as some assessment of effectiveness of ventilation. This assessment must be performed by someone who is not involved in the procedure; this person is also responsible for recording vital signs and drugs administered on a time-based graph. Monitoring must be continued until the child has returned to baseline. Patients who are receiving long-term sedation (e.g., to maintain endotracheal tube placement) may need only local anesthesia for painful procedures but may benefit from additional sedation or analgesia as well.
Many ventilated pediatric patients require sedation and some analgesia while intubated. The most common choice is a combination of a longer acting benzodiazepine and an opioid. Avoidance of oversedation is important. Use of appropriate pain and sedation scores allows for titration of medications to achieve goals of the sedation plan. Long-term use of benzodiazepines and opioids leads to tolerance, a problematic occurrence that must be considered as medications are added and weaned. True addiction is a rare occurrence, especially when medications are provided at the minimum level needed to achieve adequate sedation and pain control.
Table 46-1 Agents that Produce Sedation SEDATIVES EFFECT CONCERNS Midazolam Anxiolysis, sedation, muscle relaxation, amnesia Tolerance is possible; apnea, hypotension, depressed myocardial function; short action
Lorazepam Anxiolysis, sedation, muscle relaxation, amnesia Same as midazolam; long action
Ketamine Anesthesia, analgesia, amnesia Dissociative reactions, tachycardia, hypertension, increased bronchial secretions, emergent delirium, hallucinations; increases intracranial pressure
Chloral hydrate Sedative Emesis, hypotension, arrhythmias, hepatic dysfunction
Propofol Rapid-onset sedative for induction and Metabolic acidosis in children; may depress cardiac function maintenance of anesthesia