Chapter 12: Procedural Sedation and Analgesia

• Continuous monitoring of oxygen saturation and heart rate will identify the most common serious risk of sedation, hypoxia.

• Avoid ketamine in infants younger than 3 months due to the risk of airway complications.

• Pressure applied to the “laryngospasm notch” may reverse laryngospasm.

• Emergence reactions associated with ketamine appear to be related to the pretreatment anxiety level of the patient.

• Etomidate as a sedative is associated with few airway events, and can be used in the hypotensive patient.

• Combinations of drugs may increase adverse effects of each, such as respiratory depression.

Acknowledgment of the presence and importance of pediatric pain has transformed the management of ill and injured patients.¹ Procedural sedation and analgesia (PSA) are now an integral component of pediatric emergency care.² Increased availability of emergent imaging has expanded the emergency physician's role to include MRI and CT scan sedation.

Sedatives with or without analgesics are given for tedious, precise, or painful procedures, resulting in a level of consciousness depressed enough to accomplish the procedure while maintaining respiratory drive. The previous misnomer conscious sedation has been replaced by four levels of procedural sedation, each with increasing risk of loss of protective and cardiorespiratory functions.³ Anxiolysis or “minimal sedation” impairs coordination and cognitive function, but allows patients to respond appropriately to verbal stimuli. “Moderate sedation” retains purposeful response to verbal or light stimuli, but with profound relaxation. “Deep sedation” patients are not easily aroused yet repeated painful stimulation yields purposeful response, at doses “not likely” to depress ventilatory function. “General anesthesia” is the state where painful stimuli do not evoke a response, thus the corresponding lack of tone can compromise both airway reflexes and cardiorespiratory function.

The Joint Commission and the American Academy of Pediatrics recognize that sedation is a continuum; therefore, safety and monitoring guidelines focus on the ability to rescue a patient from a deeper level of sedation than intended.^2,4 Safety guidelines encompass patient assessment, personnel and monitoring equipment, discharge criteria, and quality assurance. Knowledge of specific medications is critical, but guidelines leave specific requirements to individual hospital credentialing committees.

The analgesic or sedative need is determined by the patient complaint, the status and responses of the child, the preference of the treating clinician, and, when appropriate, family. Prior to moderate or deep procedural sedation, children should undergo a focused history pertinent to their chief complaint using a modified SAMPLE approach⁵ (Table 12-1). In addition to obstructive airway concerns such as snoring, other factors which have been associated with an increased risk of adverse events or the need for intervention include recurrent or current stridor, obstructive sleep apnea, morbid obesity, symptomatic asthma or heart disease, gastroesophageal reflux, or swallowing problems.⁶

The importance of recent food intake is balanced in the ED by the urgency of the procedure. One emergency clinical practice guideline takes urgency, sedative type, and recent literature into account to determine reasonable fasting times (Fig. 12-1).^1,7–9

Vital signs including baseline blood pressure, oxygen saturation, and temperature should be documented, as well as a brief examination of the oropharynx, posterior pharynx, and chest. Because of the relatively larger tongue and more reactive tonsils and adenoids in children, positional respiratory compromise is more of a concern in children undergoing PSA than adults. Larger tonsils or a history of snoring or apnea should guide a clinician to consider having a nasopharyngeal airway at the bedside. Evaluate the airway using a Mallampati score or other method to assess ease of emergent intubation (Fig. 12-2).¹⁰ Any patient anticipated to be a difficult intubation, that is, those with craniofacial abnormalities, past reconstruction of the trachea, or atlantoaxial instability, merits careful risk–benefit consideration and potential general anesthesia consultation.

Assign any child undergoing PSA in the ED an American Society of Anesthesiologists (ASA) score. ASA 1 or 2 patients are generally healthy children who are good candidates for PSA in the ED; ASA 4 or 5 patients are generally better treated in a formal operating room or procedural unit. ASA 3 patients may be managed in either area depending on the nature of the problem and the capabilities of the treating physician. Rating of ASA category may be subjective; a low ASA score does not override a concerning airway evaluation.

Immediately prior to sedation, Joint Commission requirements state that patients must be reassessed to ensure that their physical condition has not deteriorated since the initial examination. The AAP guidelines call for a “time out,” documenting the patient's name, procedure, and reason for procedure.²

The mnemonic “Soap Me!” includes all aspects of equipment that should be immediately available during deep sedation (Table 12-2). Suction, oxygen, and monitoring equipment should be set up and running in the room prior to initiation of sedation, and an airway crash cart can be readily available but not opened. A bag-valve-mask setup may be left unopened in the room for moderate sedation, but should be open and ready to use for anticipated deep sedation.

Use of supplemental oxygen is controversial, perhaps because of early association with adverse events in dental clinics where its use is routine.⁸ Although critics argue it may mask hypoventilation, studies of ED sedations where supplemental O₂ is supplied have fewer hypoxia events than when it is withheld.

The degree of monitoring required is determined by the intended depth of sedation and the intended procedure. The best monitor is a skilled dedicated observer who is not involved in the procedure and who can observe the child's level of consciousness, airway patency, response to stimulation, respiratory function, and perfusion. Patients receiving analgesia alone for an acute painful condition or minimal sedation/anxiolysis generally do not require additional monitoring.

Single smaller doses of nonparenteral medications separated in time typically result in minimal sedation/anxiolysis. The sedation level anticipated with combinations and dosages given concurrently is often addressed in individual hospital policies. When 0.1 mg/kg of morphine is inadequate for severe fractures or when adjunct parenteral benzodiazepines are needed (e.g., femur fracture), monitoring with a minimum of continuous pulse oximetry is warranted.¹¹

Patients undergoing moderate or deep procedural sedation require continuous cardiac and pulse oximetry monitoring, with intermittent blood pressure and respiratory rate checks. Generally, electronic monitoring should be in place prior to sedation initiation. In difficult circumstances, PSA may begin with bedside monitoring by an appropriately trained nurse or physician after a check to ensure the electronic equipment works. A child who continually screams and thrashes from the blood pressure cuff, oximetry, or an end-tidal CO2 monitor is in danger of laryngospasm or postsedation emergence. The offending monitor can be removed after baseline vitals immediately prior to sedation and replaced when the child is asleep.

Deep sedation requires an additional person whose sole responsibility is to monitor the patient. Using moderate sedation, the sedationist can perform a procedure with a person monitoring who can intermittently assist with the procedure. The sedationist should understand monitoring equipment, recognize the signs and symptoms of respiratory depression, and be able to provide effective bag-valve-mask ventilation should apnea occur.

The most common serious risk of PSA is hypoxia from respiratory depression. Continuous pulse oximetry can provide both an ongoing assessment of oxygenation as well as a continuous display of heart rate. Pulse oximetry may not reflect hypoventilation, particularly if supplemental oxygen is being provided. For children in whom it is important to maintain normal arterial CO₂ tensions, a continuous end-tidal capnometer (ETCO2) should be added to the monitoring equipment. In addition to providing information about apnea and obstruction in advance of oximetry, the ETCO2 wave form shows each exhalation, giving information about perfusion, shallow breathing, coughing, or erratic breaths suggesting waking or obstruction.¹² Patients who are physically removed from the ED (i.e., to radiology) should have ETCO2 monitoring. In cases where the patient's respiratory effort is difficult to assess even at the bedside (e.g., the obese patient with a gluteal abscess to be sedated prone), ETCO2 may also be useful.

The timing and duration of patient monitoring is determined by both the agent used and the procedure performed. Sedation clinical monitoring can also be based on sedation phase. Phase I sedation is when the patient is receiving or has received a drug, which is achieving its peak clinical effect. During this time, a 1:1 level clinical monitoring needs to occur. At a minimum, any sedated children should have monitoring continued until the clinical effects of their drug therapy have dissipated, the pharmacologic peak is past, and the child's respiratory and mental status have approached baseline. This is extremely important in children undergoing acute painful procedures such as fracture reductions. The greatest risk of hypoventilation in these children may occur after the painful stimuli of the procedure have ceased. Conversely, children who initially present extremely agitated and crying vigorously may exhaust themselves and remain sleeping long after the pharmacologic effects of a sedative have passed. Patients receiving long-acting medications, or for whom reversal agents were required, may require monitoring until peak medication action is passed. The duration of patient monitoring must be determined individually.

Discharge of children undergoing PSA should not occur until the child has normal vital signs, has returned to an appropriate presedation mental and physical baseline, is able to sit without assistance or maintain head control if they are still in a child seat. After-care instructions should reflect the fact that the child has received an agent that may alter mental status and must therefore receive close supervision and have limited high-risk play/recreation.

Properly staffed and prepared EDs have demonstrated low complication rates for all PSA patients, with no published aspirations or deaths. Implementation of current guidelines has further improved hospital sedation safety.^13–15

Intravenous (IV) administration offers the greatest flexibility in terms of titrating medications to a specific patient response and is the preferred route for a child when medication titration is anticipated or deep sedation is planned. Intramuscular (IM) and subcutaneous (SQ) injections provide reliable delivery but should be reserved for drugs with well-established dose–response relationships (e.g., ketamine) to avoid repeated administration. Oral (PO) administration should be reserved for drugs with predictable actions, or in cases when placement of an IV is not possible until oral sedatives take effect (e.g., strong, combative patients with autism). The timing of repeat doses can be difficult to determine due to delays in absorption and onset of action.

Transmucosal (TM) drug administration provides quicker onset than PO administration but is slow enough to make titration of medications difficult. Analgesic and sedative medications such as methohexital, midazolam, and fentanyl have been successfully delivered transmucosally through the oral, buccal, intranasal, and rectal routes.^16–19 Aerosolized intranasal midazolam delivery provides effective and well-tolerated TM delivery, making it ideal for short procedural sedation situations, such as simple laceration repair in young children.²⁰

Inhalation of nitrous oxide (N2O) and methoxyflurane has been described in children in the ED setting and is safe and relatively well-tolerated route of delivery.^21,22 Advantages of this route include ease of delivery and painless administration; the disadvantages are the need for specialized equipment and patient cooperation.

Clinicians using common sedative and analgesic agents for PSA should be familiar with their indications, their actions, relative contraindications, and potential alternatives (Table 12-3).²³

Minimal sedation/anxiolysis in the ED is commonly provided for laceration repair when a topical anesthetic will provide pain control, or when a patient is anxious about a brief painless procedure (e.g., CT scan). Regimens which will not require an IV are preferred. Benzodiazepines, the most commonly used sedative hypnotic agents for anxiolysis, act on γ-aminobutyric acid (GABA) receptors and are reversible with the competitive antagonist flumazenil if needed. Midazolam is a short-acting benzodiazepine commonly used for procedural sedation in the ED setting. Oral midazolam doses of 0.5 to 1 mg/kg as a single agent typically result in calmness within 15 to 30 minutes, while intranasal delivery at 0.3 to 0.5 mg/kg takes effect in 5 to 15 minutes.¹⁷ The medication may burn during nasal administration, and is more associated with paradoxical reactions and subsequent irritability at home than the oral route (6%).¹⁸ Rectal doses of 0.45 to 1 mg/kg have achieved efficacy up to 93% for laceration repair, but result in up to 27% agitation.²⁴ IV administration results in a paradoxical reaction in 1.4% of patients, which can be reversed with flumazenil.²⁵

The combination of oral midazolam and Fentanyl resulted in more vomiting during laceration repair, but enteral hydrocodone and midazolam have not been adequately studied.²³ Since the time of peak effect of hydrocodone is 1.3 hours, it may be more effective if given in triage rather than immediately before a procedure.

Nitrous oxide is an inhaled sedative analgesic that does not function through opioid receptor stimulation. Administered as an oxygen–nitrous oxide mixture, it has an onset of action of 2 to 3 minutes and a similar duration of action. This drug is not metabolized and is excreted only through exhalation by the lungs. The minimal concentration with any clinical efficacy is a 30% nitrous oxide to 70% oxygen mixture, typically slowly dialed up to 50% to 50% mixture or delivered premixed in the 50:50 ratio with a dose-dependent effect. Considered “minimal sedation/anxiolysis” up to 50%, at concentrations of 51% to 70%, it is considered moderate, and can become deep when adjunct opioids are given.²⁶ Older demand-valve nitrous oxide systems designed for self-administration have been supplemented by continuous flow systems (via either face mask or nasal hood) applicable to young children.^26,27 For laceration repair, N₂O delivered by a free flow system with a scavenger was found to be more effective and associated with better care-giver satisfaction than midazolam or nitrous and midazolam in combination.²⁶ Because of its rapid diffusion, N₂O is contraindicated with trapped air (e.g., pneumocephalus or pneumothorax) and may cause ear pain in patients with otitis media. Vomiting (in 10%–20% of patients) can be lessened with a slow increase in percentage of N₂O.

As the distinction between minimal and moderate sedation is clinically nuanced, institutional guidelines often arbitrarily define “moderate” based on types and doses of medications. Traditionally, combinations of IV opioid and benzodiazepines in variable doses are considered moderate sedation, resulting in profound relaxation during which a patient can still respond to verbal stimuli. Multiple redoses may be needed before patients will tolerate painful procedures; however, and adverse events may be more common than with “deep” sedatives due to synergistic respiratory depression. One study described airway complications in 6.1% of ketamine sedations, compared with 19.3% of those using fentanyl/midazolam.¹³

Ketamine has become the most commonly used sedative for painful emergency procedures. As a dissociative analgesic agent, it produces a trance-like cataleptic state through disruption of communications between the cortical and limbic systems. Within 2 minutes after induction, patients rarely respond to repeated painful stimulation. The safety profile is better than combinations of benzodiazepines and opioids, and spontaneous respiratory drive is maintained even with large doses. For induction, 4 to 5 mg/kg IM or 1.5 mg/kg IV has been found to be effective doses.^28,29 It should not be used in children younger than 3 months.

Ketamine has mild sympathomimetic effects that can decrease bronchospasm, raise systemic blood pressure, and produce tachycardia. Ketamine increases intracranial pressure and should be avoided in children at risk for increased intracranial pressure. Transient apnea has been reported when the drug has been administered by rapid intravenous bolus, so administration over 60 seconds is prudent.¹⁵

Ketamine increases protective airway reflexes, but a <1% incidence of transient laryngospasm has been reported with rare reports of persistent laryngospasm after IM ketamine leading to intubation without cardiorespiratory sequelae.^28,30 Use of atropine has been shown to decrease hypersalivation with a significantly decreased percentage of postsedation vomiting.³¹

The low incidence of laryngospasm drives extrapolation of data from anesthesia which suggests upper airway infections, asthma, and secretions are risk factors.³² Given the risk, a useful location to know is the “laryngospasm notch” (Fig. 12-3) in which pressure is applied inwardly and anteriorly. Its effectiveness has been attributed to either pain from pushing the styloid process reversing supraglottic obstruction or an unknown physiologic response.

Other complications with ketamine include emergence reactions, ranging from confused agitation to vivid hallucinations to hours of screaming. The widely varying incidence reported is roughly 15% for mild and <2% for severe agitation. Emergence reactions appear to be related to the child's level of anxiety prior to the procedure, so pretreatment with a benzodiazepine may be helpful for the anxious child. Midazolam after ketamine administration has not been shown to decrease emergence, but may cut the 20% rate of vomiting to half.³³

Medications in this group are also referred to as sedative hypnotic agents because of the ability to sedate patients and induce sleep. Most of the agents in this class exert their effect through the GABA receptor of central nervous system neurons. Delivery of subtherapeutic doses of any agents in this class will cause disinhibition in the child and may result in agitated, uncontrolled behavior with an increased risk of laryngospasm. More of the sedative hypnotic agent will take the child through the plane of disinhibition to one of somnolence.

Barbiturates are the classic pediatric sedative agents (i.e., pentobarbital, thiopental, and methohexital). Medications in this class produce predictable sedation with variability in effects related to their lipid solubility and rate of central nervous system penetration. Thiopental production has been permanently halted (due to ethical concerns in its use in capital punishment) and has largely been replaced by etomidate as an induction agent for rapid-sequence intubation protocols. Methohexital, however, has a similar onset and dosage as propofol when administered IV, and can be used as a continuous bolus for patients needing an MRI for whom propofol is contraindicated. Both rapidly penetrate the central nervous system and induce profound sedation within 30 seconds. Respiratory depression is a prominent feature of IV administration of these drugs at standard induction doses, and apnea should be anticipated. Rectal administration of 25 to 30 mg/kg of methohexital has proved effective for sedation of children undergoing diagnostic radiology studies, with transient airway events in 4% to 10%.^16,34 Absorption via this route may be rapid, and parents holding a child after administration of the drug should be closely supervised, sitting down, and positioned as if the child is already sleeping.

Pentobarbital is a rapid-acting, less-potent sedative hypnotic used primarily in sedation for very brief diagnostic studies. Administered either IV or IM, this agent produces very predictable actions, with a success rate of 97% for diagnostic studies. Pentobarbital produces better, more reliable sedation than benzodiazepines alone, but is outperformed by and has more complications than etomidate for CTs.³⁵ “Pentobarbital rage” can occur in up to 7% of patients. Most protocols give up to 6 mg/kg in two to three rapid-push divided doses, stacking doses every 30 seconds if the preceding one does not result in sleep. Barbiturates have the advantage of not burning with administration, but may be hyperalgesic, and should be avoided in patients with known temporal lobe seizures.

Propofol is an ultrashort-acting sedative hypnotic used for both rapid sequence intubation (RSI) and PSA. Propofol's mechanism of action is unclear and may relate to both a GABA receptor effect and a direct neuronal membrane action. Propofol is a highly lipid soluble agent that produces clinical effects within 30 seconds (one arm brain circulation) with a duration of 6 to 8 minutes. Relative contraindications include severe allergies to egg or soy. For procedures such as fast CTs and lumbar punctures, recent studies use a 2 mg/kg bolus, with supplemental boluses of 1 to 2 mg/kg to maintain the sedation during the procedure.⁶ For prolonged sedation (i.e., MRI), a propofol bolus followed by a continuous infusion of 100 to 150 mcg/kg/min is preferable to intermittent boluses.³⁶ ED-only studies have started with 1 mg/kg when adjunctive opioids have been used.^9,37 Emergency physician administered propofol sedation has been reported in a large study of over 25,000 sedations showing a low (2.3%) rate of reversible serious adverse events.³⁸ Propofol burns with injection, which can be mitigated by a 1 mg/kg lidocaine mini-bier block applied with tourniquet for 1 minute prior to delivery. Pain is less of an issue in older patients, particularly when an anticubital vein is used.

Airway events are the most common complications, given the profound relaxation of tone seen with propofol. The need for repositioning of the head should be expected at induction, with jaw thrusts being required 3% of the time.^9,39 One study comparing methohexital and propofol in adults noted brief bag-valve-mask in 4/52 methohexital patients and 2/51 propofol patients.⁴⁰ Hypotension with good perfusion is common and does not require treatment; one study found that supplemental IV fluids resulted in a mean change of systolic blood pressure of 22 mm Hg compared with 21 mm Hg in children who were not bloused.³⁹

Supplemental oxygen seems to decrease the incidence of the most common side effect, mild hypoxia. Despite the greater frequency of airway-related events with propofol, serious adverse events are rare when deep sedation guidelines are followed and ED practitioners trained in airway management administer the drug. Given the growing ED popularity due to rapid resolution of effects and efficacy, propofol clinical practice guidelines for ED use were published in 2007.^14,41

As propofol can actually act as an antiemetic, it can balance the common side effect of ketamine. Ketamine/propofol (ketofol) can be mixed 1:1 in a single syringe and titrated to effect, or given sequentially. This combination has been shown to be highly efficacious, with short recovery times, few adverse events, and high satisfaction scores.^42–44 One unique side effect of propofol is the blunting of sympathetic responses, particularly cardiac.⁴⁵ Patients are uniquely susceptible to vagal stimulation, resulting in rare bradycardia and deaths reported. Adjunct atropine should be readily available, though is not required for routine use in children with normal cardiac function.

Etomidate is an imidazole sedative hypnotic agent most commonly used as an induction agent for emergency intubations. It has a flat cardiovascular curve and is appropriate for hypotensive patients. Dosing at 0.3 mg/kg in a fast push brings on sedation within 30 seconds.⁴⁶ In contrast to propofol, barbiturates, or opioid/benzodiazepine combinations, etomidate is associated with few airway events in children.³⁵

Etomidate does not provide analgesia, thus, adjunct opioids are required for ED procedures such as fracture reductions. Fentanyl combined with etomidate has provided effective sedation, successful procedural completion, and rapid recovery with a median time from administration to discharge of 21 minutes in children.⁴⁷ Studies evaluating its use for pediatric painful procedures have started at 0.2 to 0.3 mg/kg, with adverse events consisting of hypoxia and respiratory depression, but no reported apnea.^48,49

Side effects include burning with injection and brief myoclonus up to 22% of the time. In adults, myoclonus has been reduced by pushing more rapidly, or by giving small 0.015 mg/kg doses of midazolam prior to administration.^50,51 Sedation from etomidate in a single bolus wears off as or even more rapidly than with propofol, which may limit its applicability in the ED. The adrenal suppression reported with prolonged ICU use can occur transiently with even a single dose. Recent evaluation of ICU patients with meningococcemia found greater death rates in patients who were intubated with etomidate rather than other sedatives; thus, it should not be used for procedures in potentially septic or critically ill patients.^52,53

Dexmedetomidine, related to clonidine, is a centrally acting α₂-adrenoceptor agonist with potent sedative, analgesic, and anxiolytic actions. This drug produces minimal respiratory depression. Initial hypertension followed by hypotension and bradycardia are potential side effects diminished by loading over 10 minutes, which may limit ED utility. It does not interfere with EEG recording as compared with other sedative agents. Recovery is relatively slow, and its use has been evaluated for noninvasive prolonged studies.⁵⁴ Studies in children during CT scans found a 2 μg/kg bolus over 10 minutes to be effective, with no adverse airway events in 62 children.⁵⁵ Combinations of dexmedetomidine and ketamine were less satisfactory than ketamine/propofol, but buccal and intranasal routes of administration may be promising future applications for agitated children where an IV is not possible.^42,56

Because of their short attention spans and susceptibility to suggestion, children are excellent candidates for nonpharmacologic sedation and analgesia techniques. Distraction either through intensive conversation, storytelling, or visual or tactile stimuli is effective at diverting a child's attention from a brief painful procedure such as a local infiltration or IV injection. Music via earphones or videos may occupy a child for performance of a more prolonged procedure.

In newborns, a highly concentrated sugar solution has been shown to decrease observational scores during painful procedures, such as circumcisions. The mechanism of action for this effect appears to be related to induction of central nervous system encephalins. About 1 to 2 mL of a 50% sucrose solution and sucrose-coated nipples have proved effective in decreasing crying in neonates undergoing heel sticks or venipunctures.

Hospital or departmental policies that permit access to a comprehensive choice of medications allow treating physicians to match a child more appropriately to the correct PSA agent. Overly restrictive ED formularies may force performance of a procedure with a less-than-optimal drug and increase the possibilities of an injury or adverse advent. PSA selection is also dictated by the intended effect on a child (e.g., cooperation for a painless diagnostic procedure).

Combinations of different agents may be used to take advantage of the desired properties of each. The most frequent combinations pair short-acting sedatives with short-acting narcotics such as fentanyl/midazolam or fentanyl/propofol. Caution should be maintained because not only will the desired effects be enhanced but adverse effects may also be increased. Doses lower than those of either agent alone should be used initially when combining potent agents. Combining a local anesthetic with a sedative can also produce effective patient control. The regional anesthesia permits pain control, and the sedative produces anxiolysis and cooperation for the procedure such as lumbar punctures and laceration repairs. Potential agents for desired clinical outcomes are listed in Figure 12-4.

An emergency physician may need to provide sedation for an agitated or psychotic patient for minor procedures. Orally dissolving tablets of atypical antipsychotics for patients who already carry a psychiatric diagnosis (autism and schizophrenia) may be considered. These have been shown to be more effective than haloperidol, with less risk of extrapyramidal side effects.⁵⁷ Intramuscular midazolam also has been proven more effective and safer than IM haloperidol.⁵⁸ Newer antipsychotics such as ziprasidone result in sedation in 15 minutes when given IM, but have largely been tested only in adults⁵⁹ For pediatric patients, repeating an oral dose of medications the patient already takes is an option. For psychosis, starting with low doses and repeating in 20 minutes after consultation with a psychiatrist is recommended. In children with autism and other behavioral disorders, dexmedetomidine with or without an oral premedication, has been shown to be a highly effective agent especially in obtaining radiographic imaging.⁶⁰

Children with underlying medical conditions, frequently referred to as children with special health care needs (CSHCN), may require PSA both for problems related to their underlying conditions and for acute problems common to all children. Often, sedation or analgesic agents are withheld for fear of complications related to preexisting conditions. In reality, these patients are more appropriate candidates for PSA to avoid undue physiologic or psychological stresses.

The approach to PSA in this population is the same as for any other child, except that selection of the PSA agent must take into account not only the child's acute problem but also preexisting conditions. Whenever possible, coordination of sedation with a child's medication schedule should be attempted (e.g., after a dose of their scheduled neuropsychiatric or seizure medication). Children with cardiovascular problems should be managed with agents such as fentanyl, which have little blood pressure or heart rate effects. Children with respiratory pathology or anatomic upper airway difficulties may best be served with regional anesthesia or a drug with minimal ventilatory effects such as ketamine. Children with hepatic or renal failure may be more sensitive to barbiturate and other drugs, requiring prolonged postprocedure observation. Anesthesiology consultation should be considered, particularly for patients who are ASA class 3 or above.