Procedural sedation in adults in the emergency department: General considerations, preparation, monitoring, and mitigating complications

INTRODUCTION — Procedural sedation and analgesia (PSA) reduces the patient's discomfort, apprehension, and potentially unpleasant memories associated with procedures. The preparation to perform procedural sedation in adults, including monitoring and anticipating and managing complications, will be reviewed here.

Medication selection and dosing for procedural sedation, as well as discharge criteria, are discussed separately. (See "Procedural sedation in adults in the emergency department: Medication selection, dosing, and discharge criteria".)

TOPIC SCOPE — This topic provides guidance for procedural sedation in adult patients performed in the emergency department and other settings where the sedation is being performed by the proceduralist or a non-anesthesia clinician (eg, intensive care unit, procedural suite).

●Procedural sedation in children is discussed separately. (See "Procedural sedation in children: Approach" and "Procedural sedation in children: Preparation" and "Procedural sedation in children: Selection of medications".)

●Procedure sedation performed by endoscopists is discussed separately. (See "Gastrointestinal endoscopy in adults: Procedural sedation administered by endoscopists" and "Adverse events related to procedural sedation for gastrointestinal endoscopy in adults".)

●Monitored anesthesia care (MAC) by an anesthesia clinician is discussed separately. (See "Monitored anesthesia care in adults".)

DEFINITIONS — Procedural sedation involves the use of short-acting medications to provide analgesia and light-to-moderate sedation that enables clinicians to perform procedures effectively while monitoring the patient closely for potential adverse effects. This process was previously (and inappropriately) termed "conscious sedation," but because effective sedation often alters consciousness, the preferred term is "procedural sedation and analgesia" (PSA) [1].

●International Committee for the Advancement of Procedural Sedation – "The practice of procedural sedation is the administration of one or more pharmacological agents to facilitate a diagnostic or therapeutic procedure while targeting a state during which airway patency, spontaneous respiration, protective airway reflexes, and hemodynamic stability are preserved, while alleviating anxiety and pain" [2].

The Committee further notes that procedural sedation may occur with concurrent blunting of airway reflexes with local anesthesia and that sedation states within the purview of the definition include minimal sedation, moderate sedation, dissociative sedation, and deep sedation. It further notes that procedural sedation differs from general anesthesia, "which targets an unarousable state in which airway intervention is often required and spontaneous ventilation is frequently inadequate" [2].

●Joint Commission/American Society of Anesthesiologists (ASA) – In the United States, the Joint Commission and ASA have defined the levels of sedation on a continuum (table 1) [3-5]. It is not always possible to predict how an individual patient will respond, and many sedatives can cause rapid changes in the depth of sedation.

●Glossary of terms – Common terms include the following:

•Analgesia – Relief of pain without intentionally producing a sedated state. Altered mental status may occur as a secondary effect of medications administered for analgesia.

•Minimal sedation (anxiolysis) – The patient responds normally to verbal commands. Cognitive function and coordination may be impaired, but ventilatory and cardiovascular functions are unaffected.

•Moderate sedation and analgesia – The patient responds purposefully to verbal commands alone or when accompanied by light touch. Protective airway reflexes and adequate ventilation are maintained without intervention. Cardiovascular function remains stable.

•Deep sedation and analgesia – The patient cannot be easily aroused but responds purposefully to noxious stimulation. Assistance may be needed to ensure the airway is protected and adequate ventilation maintained. Cardiovascular function is usually stable.

•General anesthesia – The patient cannot be aroused and often requires assistance to protect the airway and maintain ventilation. Cardiovascular function may be impaired.

•Dissociative sedation – A trance-like cataleptic state in which the patient experiences profound analgesia and amnesia but retains airway protective reflexes, spontaneous respirations, and cardiopulmonary stability as defined in the American College of Emergency Physicians Policy Statement for Unscheduled Procedural Sedation [6,7]. Dissociative sedation stands apart from the continuum of sedation due to its unique characteristics. Ketamine is the pharmacologic agent used for procedural sedation that produces this state. (See "Procedural sedation in adults in the emergency department: Medication selection, dosing, and discharge criteria", section on 'Ketamine sedation'.)

INDICATIONS — Procedural sedation and analgesia (PSA) may be used for any procedure in which a patient's pain or anxiety may be excessive and may impede performance. It is often useful for procedures where deep relaxation facilitates performance (eg, closed reduction of a dislocated joint). Common procedures in which PSA may be beneficial include electrical cardioversion, closed joint reduction, fracture reduction and splinting, complicated laceration repair, abscess incision and drainage, and lumbar puncture.

GENERAL CONSIDERATIONS AND PRECAUTIONS — There are no absolute contraindications to procedural sedation and analgesia (PSA). The clinician and the patient must agree that the potential benefit of PSA outweighs the potential risks, which depend upon the patient and the procedure.

Factors to consider before proceeding with PSA include:

●Age – There is no specific age above which PSA is absolutely contraindicated. Nevertheless, older patients have a slightly increased risk of adverse events such as hypoxemia, transient apnea, and vital sign perturbations [8-10]. This is due to increased sensitivity to sedatives, decreased physiologic reserve, medication interactions, and a smaller volume of distribution resulting in higher peak serum medication concentrations in this population [11-13]. These events tend to be relatively minor and transient and resolve with interventions such as verbal/tactile stimulation and supplemental oxygen. Very few serious adverse events have been reported and only rarely require aggressive interventions such as endotracheal intubation [9,14,15]. However, individual hospital policies may specify which older patients, taking into account comorbidities, are considered inappropriate for PSA outside of the operating room.

●Comorbid conditions – There is insufficient evidence to suggest which patients are inappropriate for PSA in the emergency department based on comorbidities alone. Patients with major comorbid medical conditions, correlating with class III or greater of the American Society of Anesthesiologists (ASA) physical status classification system (table 2), are at increased risk for adverse events with PSA [11,13]. Important comorbidities are those that increase patient susceptibility to the cardiorespiratory depressant effects of sedatives and include heart failure, chronic obstructive pulmonary disease, obstructive sleep apnea, neuromuscular disease, dehydration, and anemia.

The 2018 ASA practice guidelines for moderate procedural sedation recommend consultation with an anesthesiologist for "severely compromised or medically unstable patients (eg, ASA status IV, anticipated difficult airway, severe obstructive pulmonary disease, coronary artery disease, or congestive heart failure)" [16]. However, clinicians may need to rely on individual hospital policies while considering availability of anesthesia consultation, urgency of the planned procedure, and local practice standards.

●Anticipated difficulty with airway, oxygenation, or ventilation – PSA is relatively contraindicated in patients who are likely to be difficult to ventilate or oxygenate if respiratory difficulties arise while the patient is sedated. In such patients, it is important to minimize sedation in order to maintain spontaneous ventilation. Consultation with an anesthesiologist is reasonable if deep sedation will be required and the pre-procedure airway examination identifies signs associated with a difficult airway (eg, obesity with obstructive sleep apnea, small mouth opening, airway cancer, radiation to the head or neck). Tools to identify potential difficult airways include the LEMON mnemonic (table 3), the “3-3-2” rule (picture 1), and the modified Mallampati classification (figure 1). Alternatives to PSA may be preferable if an anesthesiologist and proceduralist are available and any associated procedural delay would not be harmful. (See "Approach to the difficult airway in adults for emergency medicine and critical care".)

●Duration of sedation – Patients should be sedated for the shortest period necessary to perform the procedure. However, no data clearly demonstrate that a longer duration of PSA correlates with an increase in adverse outcomes.

●Time of last oral intake – Whether the patient recently ate should be considered before performing PSA, although this does not appear to have a major impact on aspiration risk [17,18]. (See 'Preprocedure fasting' below.)

PREPARATION AND MONITORING

Preprocedure fasting — We recommend not delaying an emergency procedure to ensure a predetermined preprocedural fasting period. In general, the purported benefits of preprocedural fasting do not outweigh the risks of delaying an urgent or emergency procedure. Patients undergoing emergency procedures requiring procedural sedation and analgesia (PSA) are thought to be at increased risk of aspiration because their stomachs can be full, and aspirated gastric contents above a critical volume and acidity can cause severe respiratory and systemic consequences [19]. However, extending the duration of preprocedural fasting does not decrease gastric volumes or increase pH [7,13,20-24]. Also, episodes of emesis, apnea, or hypoxemia are not reduced by periods of preprocedure fasting [25,26]. An approach to reduce aspiration risk for emergency procedures in a non-fasting patient is discussed below. (See 'Aspiration' below.)

The risk of clinically significant aspiration during PSA is extremely low and frequently does not cause harm when it does occur, except in gastrointestinal endoscopy [17,18,27,28]. A systematic review in 2017 of all published reports of aspiration involving procedural sedation (1249 publications) found no reports of aspiration events in non-fasted patients receiving procedures other than endoscopy [29]. There were nine deaths, eight of which occurred during upper gastrointestinal endoscopy; none occurred in healthy children or adults.

Although some advocate performing the procedure under general anesthesia in the operating room in patients who have not been fasting, this approach has not been proven to reduce the risk of aspiration [23,30]. Endotracheal intubation may not protect the patient from aspiration, and airway manipulation involved in performing intubation may increase the risk of aspiration [21,22,30-33]. Additionally, depending on the practice setting, a proceduralist (eg, surgeon) and anesthesiologist are often unavailable for emergency procedures.

The practice of not delaying urgent procedures for a fast is supported by society guidelines. A 2018 practice guideline by The American College of Emergency Physicians (ACEP) states: "Providers of unscheduled procedural sedation should assess the timing and nature of recent oral intake. The urgency of the procedure will dictate the necessity of providing sedation without delay regardless of the fasting status" [34]. The latest American Society of Anesthesiologists (ASA) guidelines published in 2018 state: "In urgent or emergent situations where complete gastric emptying is not possible, do not delay moderate procedural sedation based on fasting time alone" [16].

For elective procedures in adults, fasting guidelines are discussed separately (table 4). (See "Preoperative fasting in adults", section on 'Fasting guidelines'.)

Informed consent — Before performing PSA, the clinician must discuss the risks, benefits, and alternatives of the procedure and the planned sedation with the patient and ideally obtain written consent if time and the clinical situation (eg, desire to prevent infection spread during the coronavirus disease 2019 [COVID-19] pandemic) permit. Verbal or written consent can also be obtained from a family member or health care proxy if needed. Implied consent is acceptable in cases where the patient is unable to provide explicit consent due to severe pain, hemodynamic instability, or altered mental status [35]. A detailed discussion of informed consent, including in emergency situations and in patients who lack adequate decision-making capacity, is available separately. (See "Informed procedural consent".)

Personnel — The practice of providing PSA is routinely and safely performed by specialists other than anesthesia practitioners, such as emergency clinicians, critical care specialists, gastroenterologists, cardiologists, and various nurse specialists [36,37]. Clinicians providing PSA should have in-depth knowledge of the relevant drugs, including their clinical effects, doses, adverse effects, and reversal agents. Such clinicians must also be qualified to perform advanced cardiovascular life support, including airway management. (See "Advanced cardiac life support (ACLS) in adults".)

The number of clinicians needed to perform PSA and the procedure safely varies according to the patient, setting, and procedure. Administration of PSA requires at least two clinicians. In most cases, one clinician performs the procedure while another (usually a nurse) administers the sedative agents and monitors and records the patient's vital signs and clinical status. Whenever possible, we suggest that this minimum standard be met [16,27].

Some experts suggest that an additional physician (separate from the proceduralist) who is skilled in PSA and airway management should be present [13,35]. Depending on the practice setting, it may not be feasible or practical to have two physicians present for PSA. Studies have shown that PSA directed by the emergency department physician performing the procedure accompanied by an emergency department nurse had comparably low complication and high success rates when compared with two physicians present [38,39]. Guidelines from the ASA do not require the presence of a second physician but call for a designated individual other than the proceduralist who has "advanced life support skills" and can monitor the patient, obtain intravenous (IV) access, and recognize and treat complications related to the performance of procedural sedation [3,16].

●Hospital-based settings – For deep sedation in the hospital but outside of the operating room, our practice is to have an advanced practice clinician or a nurse with extensive experience in airway management and resuscitation (such as an emergency department-, intensive care unit-, or post-anesthesia care unit-experienced registered nurse) to monitor the patient's sedation in addition to the proceduralist. In all cases, there should be at least one clinician present during the procedure (either the proceduralist or monitoring advanced practice clinician or nurse) who is qualified and experienced in definitive management of the airway, including bag-mask ventilation, the placement of supraglottic devices, and endotracheal intubation.

●Free-standing outpatient settings – For PSA provided in a free-standing outpatient facility, the clinician providing PSA should be qualified to manage all levels of PSA and any complications that may arise, such as airway compromise and cardiac arrest. The clinician providing PSA should be able to recover the patient from sedation and be immediately available during the recovery period should an emergency arise. The proceduralist (eg, gastroenterologist, plastic surgeon) could be expected to provide assistance during an adverse event but should not be counted upon to provide potential lifesaving care. Multiple studies, especially in the gastroenterology literature, have demonstrated the safety of PSA in the outpatient setting [40].

Equipment and medications — All supplies necessary to perform the procedure, monitor the patient, and manage the airway and complications should be available at the bedside during the performance of PSA. These include:

●Suction to manage vomiting or oral secretions

●Airway adjuncts such as a bag-valve mask and oral and nasal airways

●Equipment to perform endotracheal intubation (see 'Monitoring' below)

●Resuscitation medications, including advanced cardiac life support medications and reversal agents (ie, naloxone and flumazenil)

IV access should be established when PSA is being performed, but the IV may be placed after administration of an oral or intramuscular sedative in selected circumstances (eg, patient with anxiety).

Monitoring — Proper patient monitoring during PSA is crucial. We recommend the following:

●Frequent vital signs – Blood pressure, heart rate, and respiratory rate should be measured at frequent, regular intervals. In a patient with major comorbid medical conditions (eg, ASA class III or greater (table 2)), we suggest increasing the frequency of blood pressure measurements during PSA.

●Continuous cardiorespiratory monitoring – For all patients undergoing PSA, we recommend continuous monitoring of oxygen saturation (SpO₂) using pulse oximetry, end-tidal carbon dioxide (EtCO₂) using capnography, and cardiac rhythm monitoring [13]. Pulse oximetry and capnography help keep patients safe during PSA, but they do not replace vigilant clinical monitoring by the PSA provider. Pulse oximetry and capnography are discussed in detail separately. (See "Pulse oximetry" and "Carbon dioxide monitoring (capnography)".)

Capnography correlates closely with arterial carbon dioxide (CO₂) and responds more rapidly to hypoventilation and apnea compared with pulse oximetry, especially when the patient is receiving supplemental oxygen [27,41-44]. Capnography can also detect upper airway obstruction, laryngospasm, and bronchospasm (algorithm 1). Even though capnography monitoring during PSA results in fewer hypoxic episodes compared with standard monitoring, there is insufficient evidence that capnography reduces significant adverse events [45,46]. A meta-analysis of trials comparing the addition of capnography in emergency department patients undergoing PSA (three trials, 1272 patients) did not show a reduction in the rate of clinically significant adverse events, but heterogeneity and reporting bias limit the extrapolation of results [47]. (See "Carbon dioxide monitoring (capnography)", section on 'Procedural sedation'.)

If capnography is not used during PSA (eg, because of unfamiliarity or unavailability), it is necessary to closely monitor the patient's respiratory mechanics (ie, chest wall rise) since pulse oximetry desaturation lags behind the onset of hypoventilation.

●Closely monitoring level of sedation – The patient's response to medications and the procedure must also be closely monitored. Level of alertness, depth of respiration, and response to painful stimuli (eg, fracture reduction) are all important factors in determining subsequent medication doses. Sedation scales, such as the Richmond Agitation Sedation Scale (table 5) and the Ramsay Sedation Scale (table 6), have not been adequately studied in the setting of PSA. They may be more useful in determining the appropriate titration of sedatives during long-term procedures (eg, mechanical ventilation).

Processed electroencephalography monitoring (ie, bispectral index [BIS] monitoring), a technology developed to monitor the level of general anesthesia, does not appear to be useful for monitoring the depth of procedural sedation [48-50]. BIS measurements do not appear to correlate well with clinical sedation and have poor reproducibility.

Supplemental oxygenation — We suggest administering supplemental oxygen to patients undergoing PSA if monitoring with capnography, which is not affected by the presence or absence of additional oxygen. If capnography is unavailable, it is reasonable to forgo supplemental oxygen to potentially detect respiratory insufficiency earlier. If administering oxygen, use a high-flow delivery system (eg, 10 to 15 L/minute via nonrebreather mask or 30 to 60 L/minute via high-flow nasal cannula).

Administering supplemental oxygen is easy to perform, is unlikely to cause harm, maintains oxygen reserves, and reduces frequency of desaturation events during PSA [3,16,51-54]. Hypoxic episodes occur commonly during PSA and occur more frequently with deeper sedation and longer procedures [55]. A trial of 117 adults undergoing propofol PSA found that patients who received oxygen 15 L/minute via nonrebreather mask were less likely to have episodes of hypoxia (SpO₂ <93 percent) lasting longer than 15 seconds compared with those receiving compressed air (19 versus 41 percent, difference 23 percent, 95% CI 6-38 percent) [56]. However, supplemental oxygen at lower concentrations (eg, 2 L/minute nasal canula) may not reliably prevent desaturation during PSA [57]. A meta-analysis (six trials, 2633 patients) found that compared with standard oxygen therapy (4 to 10 L/minute nasal canula), patients who received high-flow nasal cannula oxygen during PSA were less likely to have intra-procedure desaturation events (2 versus 13 percent, RR 0.18, 95% CI 0.04-0.87), although there was no difference in interventions or complications [58].

If capnography is not available, it is reasonable to forgo supplemental oxygen, which renders pulse oximetry ineffective as an early warning device for respiratory depression since SpO₂ may not fall until a prolonged period of hypoventilation or apnea has occurred [16,41,59]. Paying close attention to both pulse oximetry and respiratory mechanics remains critical when monitoring a patient breathing room air during PSA.

Intuitively, early detection of hypoxemia and hypoventilation would appear to be beneficial. However, there is insufficient evidence to suggest that brief episodes of either have a negative impact on patient outcome, especially if recognized quickly [35,52]. Fortunately, most desaturation episodes are brief and easily treated (eg, supplemental oxygen, jaw lift, positive-pressure ventilation with bag-valve mask), and they rarely result in serious consequences [35,57].

Both the 2018 ASA guidelines on PSA and the 2018 ACEP policy statement on unscheduled procedural sedation recommend the use of supplemental oxygen [6,16]. However, the authors of the ASA guidelines did not find sufficient evidence to support a specific oxygen delivery method [16]. Also, the ACEP policy statement says "oxygen is commonly avoided when capnography is not used, thus permitting pulse oximetry to provide warning should interactive monitoring fail to detect ventilatory compromise" [6].

SPECIAL POPULATIONS

Obesity — Adjustments in management and medication dosing are often necessary when providing procedural sedation to adults with obesity due to physiologic changes and associated health problems, such as sleep apnea and restrictive lung disease [60]. These conditions may predispose to hypoxemia and difficulties with ventilation and other aspects of airway management [61,62].

Procedural sedation and analgesia (PSA) in patients with obesity is associated with a more frequent need for airway maneuvers (eg, bag-mask ventilation) and more frequent, albeit brief, episodes of hypoxemia, but obesity does not appear to increase the incidence of serious adverse outcomes or premature termination of the procedure [63]. The physiologic changes and medical conditions associated with obesity, and important aspects of airway management in adults with obesity, are discussed separately. (See "Overweight and obesity in adults: Health consequences" and "Airway management in the morbidly obese patient for emergency medicine and critical care".)

Obesity may affect the choice of sedative agent and dosing, as pharmacokinetics and pharmacodynamics can be changed by the increased volume of distribution, altered drug clearance, and increased cardiac output seen with obesity. Adjustments in the dosing of medications used for PSA should generally be based on ideal or lean bodyweight to avoid oversedation and are described separately. (See "Procedural sedation in adults in the emergency department: Medication selection, dosing, and discharge criteria", section on 'Patients with obesity'.)

Pregnancy — PSA can be performed safely in pregnant patients with the following considerations:

●Aspiration mitigation – Standard adult fasting guidelines for PSA for elective procedures apply in pregnant patients (table 4) as delayed gastric emptying is not a factor since it only occurs during active labor and postpartum [64]. Pregnancy does not appear to increase risk of clinically significant aspiration during PSA compared with nonpregnant patients. In a retrospective review of 51,086 first-trimester and 11,039 second-trimester pregnant patients undergoing propofol PSA, there were no cases of perioperative pulmonary aspiration even though preoperative antacids were not routinely used [65]. (See "Preoperative fasting in adults", section on 'Pregnant patients'.)

Some experts routinely administer nonparticulate antacids (eg, sodium citrate-citric acid), H2 receptor antagonists, and/or metoclopramide for patients who are beyond 18 to 20 weeks gestation, while others only administer these if the patient has aspiration risk factors (table 7) [28,66]. There is insufficient evidence to determine if aspiration prophylaxis prior to the procedure has any benefit, and there is no study examining this issue regarding PSA in pregnant patients [20]. The reason for administration is that increased intra-abdominal pressure and relaxation of the lower esophageal sphincter in pregnancy predisposes pregnant patients to reflux, especially when recumbent. (See "Anesthesia for nonobstetric surgery during pregnancy", section on 'Preoperative aspiration mitigation'.)

●Positioning – The pregnant patient who is in the late second or third trimester should be placed in a 15-degree left lateral tilt when supine to reduce the risk of hypotension and resultant uteroplacental insufficiency and fetal hypoxemia. (See "Anesthesia for nonobstetric surgery during pregnancy", section on 'Positioning'.)

●Fetal monitoring – Measure the fetal heart rate before and after the procedure. This is sufficient in a pregnancy at a gestational age incompatible with ex-utero survival. In pregnancies at or beyond the gestational age compatible with ex-utero survival, continuous fetal heart rate and contraction monitoring is not required but should be individualized based on the gestational age, type of procedure, and resources available [67]. For example, a patient in the third trimester in whom there may be concern for hemodynamic instability or hypoxemia during the procedure should undergo continuous fetal monitoring. (See "Nonobstetric surgery in pregnant patients: Patient counseling, surgical considerations, and obstetric management", section on 'Fetal heart rate monitoring'.)

●Provide supplemental oxygenation – High-flow oxygen (eg, 10 to 15 L/minute via nonrebreather mask or 30 to 60 L/minute via high-flow nasal cannula) should be administered because of the risk of sedation-related maternal desaturation, primarily due to decreased functional residual capacity in pregnancy. Short periods of maternal hypoxia are generally well tolerated by the fetus because of increased oxygen affinity of fetal hemoglobin, but prolonged periods of maternal hypoxia are potentially deleterious to the fetus [64]. (See "Maternal adaptations to pregnancy: Cardiovascular and hemodynamic changes" and "Maternal adaptations to pregnancy: Dyspnea and other physiologic respiratory changes", section on 'Physiologic pulmonary changes in pregnancy'.)

●Avoid hypercarbia and hypotension – Preprocedural hydration and close monitoring can help avoid hypotension and hypercapnia, which may cause maternal acidosis, myocardial depression, and reduced uteroplacental blood flow [64]. (See "Anesthesia for nonobstetric surgery during pregnancy", section on 'Hemodynamic management'.)

ANTICIPATING AND MITIGATING COMPLICATIONS

Overview — Even though serious complications attributable to procedural sedation and analgesia (PSA) rarely occur, many complications can be prevented through appropriate selection of patients, proper use of sedative medication, and careful monitoring [27,68,69]. Adverse outcomes may include respiratory depression with hypoxia or hypercarbia, cardiovascular instability, vomiting and aspiration, emergence reactions, and inadequate sedation preventing completion of the procedure [11]. Respiratory and cardiovascular side effects can be minimized by titrating the medication in small incremental doses, titrating to desired effect, and permitting the peak effect to occur before giving additional medication [16]. Particular attention should be paid to patients in whom oxygenation and ventilation may be difficult should the need for airway management arise. Such patients may not be appropriate candidates for PSA. (See 'General considerations and precautions' above.)

According to a systematic review of 55 studies including 9652 cases of PSA performed in the emergency department, the rate of severe adverse events requiring an emergency intervention is exceedingly low [68]. Significant respiratory compromise, the most concerning potential complication, develops in well less than 1 percent of cases. Among the studies included, the review identified one case of aspiration in 2370 sedations (1.2 per 1000), one case of laryngospasm in 883 sedations (4.2 per 1000), and two intubations in 3636 sedations (1.6 per 1000).

Respiratory depression — Nearly all of the sedative agents used for PSA can cause dose-dependent respiratory depression [11]. Respiratory complications, such as oxygen desaturation, are the most common adverse events and can be minimized by cautious, unhurried medication titration [11]. Oxygen desaturation develops in up to 11 percent of adults who have PSA with either propofol or etomidate [13]. Rates are slightly higher if supplemental oxygen is not used.

Hypoventilation and apnea may occur but are usually short lived due to the brief duration of the drugs used for PSA. These complications nearly always resolve with patient stimulation, supplemental oxygen, positioning of the airway, or brief ventilatory support using a bag-valve mask. Treatment with the reversal agent naloxone or flumazenil may be necessary with more severe or prolonged respiratory depression during PSA using opioids or benzodiazepines. The use of naloxone and flumazenil are reviewed separately. (See "Acute opioid intoxication in adults", section on 'Basic measures and antidotal therapy' and "Benzodiazepine poisoning", section on 'Role of antidote (flumazenil)'.)

Cardiovascular side effects — Significant hypotension and bradycardia seldom occur but may develop in patients with significant cardiac morbidity and those taking cardio-depressant medications (eg, beta blockers) [11,70-72]. These problems are usually transient and resolve without intervention. Hemodynamically neutral sedatives (eg, etomidate) may be preferable for patients at risk from changes in blood pressure or heart rate. (See "Procedural sedation in adults in the emergency department: Medication selection, dosing, and discharge criteria", section on 'Etomidate'.)

Aspiration — We suggest the following approach to reducing aspiration risk:

●Carefully consider the risks and benefits of performing the procedure immediately. Although there is no strong evidence that longer fasting times reduce aspiration risk, it may be reasonable to wait if the patient's stomach is full (ie, reported a recent meal) and the procedure is not a true emergency [73]. Fasting times for elective procedures are provided in a separate topic. (See "Preoperative fasting in adults", section on 'Fasting guidelines'.)

If the procedure can be delayed, fasting may be particularly helpful when a potentially difficult airway or an increased risk for aspiration exists, as with the following circumstances [21,34]:

•Conditions predisposing to esophageal reflux (eg, bowel obstruction, hiatal hernia, pregnancy)

•Extremes of age (<6 months or >70 years old)

•Severe systemic disease (American Society of Anesthesiologists [ASA] class III or greater)

•Obstructive sleep apnea

•Obesity

•Gastroparesis (eg, idiopathic, diabetes, chronic opioid or glucagon-like peptide agonist use)  

•Other concerning conditions (eg, depressed mental status)

●Decrease the targeted depth of sedation and avoid deep sedation when possible. While no evidence clearly demonstrates that deeper levels of sedation increase the risk of aspiration, lighter sedation may permit the patient to maintain protective airway reflexes, which reduces risk [21].

●There is no benefit from administering preprocedural antacids or promotility medications. These medications have not been shown to reduce aspiration risk [20]. However, some experts will administer these to pregnant patients routinely or in cases of increased aspiration risk (table 7) since they are unlikely to cause harm. (See 'Pregnancy' above.)

Nausea and vomiting — Antiemetics may be used as needed to prevent and treat nausea and vomiting; however, there is insufficient evidence regarding prophylactic use or which agent is preferable. Nausea and vomiting occur in about 5 percent of patients undergoing PSA, although rates may be higher when opioids are used [74-77]. In one randomized trial involving PSA with ketamine, 16 of 127 children managed without antiemetics experienced post-procedural vomiting versus 6 of 128 children pretreated with ondansetron, a 7.9 percent reduction in absolute risk (95% CI 1.1-14.7) [78]. Sedation-related nausea and vomiting are discussed in greater detail elsewhere. (See "Postoperative nausea and vomiting".)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Procedural sedation in adults".)

SUMMARY AND RECOMMENDATIONS

●Definitions – Procedural sedation and analgesia (PSA) involves the use of short-acting medications to provide analgesia and light-to-moderate sedation that enables clinicians to perform procedures while monitoring the patient closely for potential adverse effects. This process was previously termed "conscious sedation." (See 'Definitions' above.)

●General considerations and precautions – PSA may be used for any procedure in which a patient's pain or anxiety may be excessive and impede performance of the procedure. The clinician and the patient must agree that the potential benefit of PSA outweighs the potential risks, which depend upon the patient and the procedure. There are no absolute contraindications to PSA. Relative contraindications include older age, significant medical comorbidities (correlating with American Society of Anesthesiologists [ASA] class III or greater (table 2)), and signs of a difficult airway (table 3 and picture 1 and figure 1), for which the ASA practice guidelines suggest consultation with an anesthesiologist. Clinicians may need to rely on individual hospital policies while considering availability of anesthesia consultation, urgency of the planned procedure, and local practice standards. (See 'Indications' above and 'General considerations and precautions' above.)

●Preprocedure fasting – Whether the patient recently ate should be considered before performing PSA, although the benefits of preprocedural fasting do not outweigh the risks of delaying an urgent or emergency procedure. Except for gastrointestinal endoscopy, the risk of clinically significant aspiration during PSA is extremely low and frequently does not cause harm when it does occur. (See 'Preprocedure fasting' above.)

●Personnel – The number of clinicians needed to perform PSA and the procedure safely may vary according to the patient and the procedure. Administration of PSA requires at least two clinicians. In most cases, one clinician performs the procedure while another (usually a nurse) administers the sedative agents and monitors and records the patient's vital signs and clinical status. (See 'Personnel' above.)

●Equipment – All equipment necessary for airway management should be at the bedside during PSA, including suction, airway adjuncts (eg, bag-valve mask, oral and nasal airways), and equipment to perform endotracheal intubation. (See 'Equipment and medications' above.)

●Monitoring – Proper monitoring during PSA is crucial. The patient's blood pressure, heart rate, and respiratory rate should be measured at frequent, regular intervals. We recommend continuous monitoring of oxygen saturation (SpO₂) using pulse oximetry, end-tidal carbon dioxide (EtCO₂) monitoring with capnography, and cardiac rhythm monitoring for all patients undergoing PSA. (See 'Monitoring' above.)

●Supplemental oxygen – In a patient undergoing PSA and being monitored with capnography, we suggest administering supplemental oxygen in order to reduce frequency of desaturation events (Grade 2C). If capnography is unavailable, it is reasonable to forgo supplemental oxygen, which renders pulse oximetry ineffective as an early warning device for respiratory depression since SpO₂ may not fall until a prolonged period of hypoventilation or apnea has occurred. If administering oxygen, use a high-flow delivery system (eg, 10 to 15 L/minute via nonrebreather mask or 30 to 60 L/minute via high-flow nasal cannula). During PSA, supplemental oxygen maintains oxygen reserves; however, there is insufficient evidence to suggest that brief episodes of hypoventilation have a negative impact on patient outcome, especially if recognized quickly. (See 'Supplemental oxygenation' above.)

●Anticipating and mitigating complications – Serious complications attributable to PSA rarely occur. Significant respiratory compromise develops in less than 1 percent of cases. Adverse outcomes may include respiratory depression with hypoxia or hypercarbia, cardiovascular instability, vomiting and aspiration, and inadequate sedation preventing completion of the procedure. (See 'Anticipating and mitigating Complications' above.)

•Respiratory complications – Oxygen desaturation is the most common adverse events and can be minimized by cautious, unhurried medication titration. Desaturation nearly always resolves with patient stimulation, supplemental oxygen, positioning of the airway, or brief ventilatory support using a bag-valve mask. (See 'Respiratory depression' above.)

•Cardiovascular – Significant hypotension and bradycardia seldom occur but may develop in patients with significant cardiac morbidity and those taking cardio-depressant medications but are usually transient and resolve without intervention. Cardiovascular events can be mitigated by choice of medications that are hemodynamically neutral (eg, etomidate). (See 'Cardiovascular side effects' above.)

•Aspiration – Risk of aspiration can be reduced by carefully considering the risks and benefits of performing the procedure immediately and by avoiding deep sedation. (See 'Aspiration' above.)

•Nausea and vomiting – Antiemetics may be used as needed to prevent and treat nausea and vomiting; however, there is insufficient evidence regarding prophylactic use or which agent is preferable. (See 'Nausea and vomiting' above.)