Background

Procedural sedation and analgesia (PSA) is a core competency for emergency physicians (EP) that is commonly practiced.^1–4 PSA entails suppressing a patient’s level of consciousness with sedative or dissociative agents to alleviate pain, anxiety, and suffering to enhance medical procedure performance and patient experience (Table 22.1).^{1, 5}

Indications

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  Traumatic injuries account for the greatest number of sedations in the emergency department (ED).^6–12

  
  
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  ED PSA for the severely injured trauma patient may be limited to life-saving interventions (LSI). Tube thoracostomy and cricothyrotomy may require PSA in addition to injection of local anesthetic agents.¹³

  
  
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  LSI and emergent procedures necessitate procedural performance in the ED. For urgent and non-urgent procedures, however, lengthy procedures and higher risk patients may benefit from PSA in the operating room or with anesthesiology staff support in the ED.

  
  
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  Agitated trauma patients may require sedation for diagnostic procedures, such as neuroimaging (Box 22.1).¹⁴

Preparation

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  The American Society of Anesthesiology (ASA) physical status classification is a useful tool for risk stratifying patients by their medical history.^14–16 ASA Class I and II are associated with significant adverse event rates <5%, while risk increases with greater ASA Classes (Table 22.2).^{16, 17}

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  Evaluate for difficult bag valve mask ventilation, difficult intubation, allergies, and PSA agent contraindications.

  
  
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  Be prepared to respond to airway obstruction, apnea/hypoventilation, hypotension, dysrhythmia, and emesis.^14–16

  
  
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  Fasting state is often considered, but aspiration of emesis during ED PSA is rare, and preprocedural fasting does not decrease risk.^{1, 19}

  
  
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  End tidal carbon dioxide monitoring is not required, but it may detect apnea/hypoventilation before pulse oximetry, especially in patients on supplemental oxygen.^20–22

  
  
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  Important equipment recommended for procedural sedation is listed in Box 22.2.

Medication Choices

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  Consider airway status, ventilatory function, hemodynamic state, and previous opioid analgesic administrations when selecting the appropriate agent and dose.

  
  
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  Reduced doses titrated to sedation goals are appropriate in hypovolemic, elderly, and obese patients.^{15, 16}

Discharge Considerations

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  The ability to urinate or tolerate PO prior to discharge is not universally required; the need for this may be case-by-case specific.³⁴

  
  
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  All patients should be required to have another responsible party with them prior to discharge.

  
  
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  No data has demonstrated a required amount of time post-sedation before discharge.³⁴

  
  
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  ED should have sedation-specific discharge instructions to provide the patient.

  
  
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  Discharge time needs to be adjusted if a reversal agent was given based on drug-specific pharmacokinetics.

  
  
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  Box 22.3 depict discharge criteria after PSA.

Special Populations – Pediatrics

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  Pediatric patients frequently require sedation for additional reasons beyond adults (e.g. psychological challenges, developmental delays).

  
  
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  Ketamine is frequently used with a large safety margin³⁵; ketamine-associated emesis and agitation are more frequent with older children.³⁶

  
  
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  Barbiturates are not recommended; they have no intrinsic analgesic properties.³⁷

  
  
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  Sedation in children is often more difficult to titrate, with greater variability in the level of sedation achieved.^{38, 39}

  
  
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  Consider alternative routes of administration in order to obviate challenges associated with IV placement (e.g. oral midazolam, oral ketamine, intranasal ketamine, intramuscular ketamine); consider IV placement after sedation is achieved.⁴⁰

  
  
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  Advanced airway equipment specific to patient size should be readily available.⁴¹

  
  
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  Use of an independent observer of patient hemodynamic/respiratory status reduces the risks of adverse events (does not have to be physician, consider having a dedicated nurse or qualified technician, if available).⁴¹

  
  
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  Pediatric-specific protocols may reduce adverse events, especially in very young children.⁴²

  
  
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  NPO status is a consideration; but ED-based procedures are often not “elective” and, thus, clinicians must evaluate each patient encounter risk/benefit.^{1, 43}

  
  
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  ACEP Clinical Policy states: “Do not delay procedural sedation in adults or pediatrics in the ED based on fasting time. Preprocedural fasting for any duration has not demonstrated a reduction in the risk of emesis or aspiration when administering procedural sedation and analgesia.” (Level B recommendation)¹

  
  
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  Table 22.6 discusses key considerations in oral intake before sedation from the AAP and ASA, though ACEP recommends that no fasting is required before sedation.

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  Consider using the University of Michigan Sedation Scale (UMSS) to guide sedation goals, which is simple and reproducible (Table 22.7).⁴⁵

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  Box 22.4 depicts discharge criteria for pediatric patients after PSA.

Special Populations – Pregnancy

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  There is very little data to guide PSA in the pregnant patient. ACEP does not have a specific clinical policy on this population.⁴

  
  
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  Significant physiologic changes occur in pregnancy: plasma volume and cardiac output increase along with a commensurate increase in respiratory volume and rate to compensate for metabolic demands ➔ decreased ability to compensate during hemodynamic stress and more rapid deoxygenation.⁴⁷

  
  
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  Regional anesthesia may be used as an alternative (lidocaine is pregnancy class B).

  
  
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  Meperidine (pregnancy class B) may be preferred over morphine (pregnancy class C).⁴⁸

  
  
  
  
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    May be reversed with naloxone (pregnancy class B).

  
  
  
  
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  Propofol is the preferred agent (pregnancy class B).⁴⁸

  
  
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  Avoid benzodiazepines (pregnancy class D; known teratogenic effects).

  
  
  
  
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    Flumazenil risk unclear (pregnancy class C).

  
  

Special Populations – Elderly

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  Age, in and of itself, is not a contradiction to sedation.⁴⁹

  
  
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  Very little ED-specific data on sedation in the elderly; most data are extrapolated from anesthesia and dental literature.

  
  
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  Generally, elderly patients often require lower dosing and have higher risk of adverse events compared to other patient populations.^{50, 51}

  
  
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  For propofol, consider administering an “age based” test dose. A rough estimate may be 100 mg minus the patient’s age (e.g. for a 75 year old patient, start with 25 mg).⁵²

  
  
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  In elderly >70 years, half-dose titration of propofol and benzodiazepines is preferred to avoid adverse events.^{49, 50, 53–55}

  
  
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  While ketamine has some theoretical risks in the elderly, that has not been borne out in the data. Ketamine use appears safe in the elderly.^56–58

  
  
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  While we do not recommend etomidate for procedural sedation due to the high-risk of myoclonic reactions, it appears safe for use in the elderly.⁵⁹

Pitfalls

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  Pushing additional boluses of PSA agents (especially propofol) too quickly and inducing hypotension or hypopnea – wait an appropriate length of time for the drug to take effect before repeat dosing to reduce adverse event risk, which may have dose-dependent effects.⁵²

  
  
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  Drugs can have stacking-effects when given together. Drugs given before the sedation may potentiate the likelihood of an adverse event.⁶⁰

  
  
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  Airway related complications are not always predictable; have appropriate airway equipment available and ready before starting sedation.

  
  
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  Consider adjusting dosing for patient characteristics that may affect medication metabolism (e.g. age, body mass, liver function, kidney function).