How To Do Procedural Sedation and Analgesia

• Relieve pain and/or anxiety that occurs with therapeutic or diagnostic procedures*

• Facilitate a procedure by relaxing the patient and reducing patient motion

• Provide amnesia for a procedure, thereby sparing the patient possible psychological trauma

* Procedures include, but are not limited to, cardioversion, joint or fracture reduction, arthrocentesis, abscess drainage, laceration repair, foreign body removal, lumbar puncture, vascular access and cannulation.

Absolute contraindications

• Urgent need for treatment (eg, hemodynamic instability) that cannot await sedation

• Hypersensitivity to one of the medications*  

• < 3 months (increased risk of airway compromise)

• Particular to nitrous oxide: Pneumothorax, pneumomediastinum, bowel obstruction, or intraocular gas bubble (post-vitreoretinal surgery), which are sites of air accumulation into which nitrous oxide can expand

Relative contraindications

• Severe cardiopulmonary disease (increased risk of decompensation from respiratory depression)†

• Obstructive sleep apnea†

• Obesity or anatomic characteristics (eg, micrognathia, macroglossia, short neck, congenital anomalies) that suggest difficult intubation†

• Chronic liver or kidney disease: Some medications will be metabolized slowly, leading to prolonged sedation.

• Patients > 60 years of age (increased risk of decompensation): PSA medication doses should often be decreased.

• Acute sedative medication or drug intoxication (increased risk of respiratory complications): PSA medication doses should be decreased.

• Chronic alcohol or substance use disorder: PSA medication doses may need to be increased.

• Pre-procedural food or drink: Review institution-specific protocols regarding fasting before PSA‡

‡ Although some guidelines recommend delaying elective procedural sedation for a few hours after ingestion of clear liquids and 8 hours after ingestion of solids, no data establish the efficacy or necessity for doing so (3).

• Respiratory depression

• Oxygen desaturation

• Hypotension (rarely significant in the absence of concurrent serious disease or cardiovascular compromise)

• Aspiration (rare)

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• > 30 to 60 seconds]); sympathomimetic effects (hypertension, tachycardia, which pose risk to patients with ischemic heart disease or underlying hypertension); on recovery, vomiting or emergence reactions (anxiety/panic/hallucinatory episode), more frequent in adults than in children

• Monitoring equipment (pulse oximeter, capnograph [end-tidal CO2 monitor], blood pressure cuff, cardiac monitor)

• IV catheters and fluid (eg, 0.9% saline)

• Supplemental oxygen (with high-flow capacity)

• Suction source and tips

• Airway management equipment, especially a bag-valve-mask (BVM)

• Cardiopulmonary resuscitation equipment

• PSA medications and reversal agents (see examples below)

• Additionally, for nitrous oxide administration: Fail-safe gas administration equipment (built-in lower limit of 30% oxygen delivery); demand valve mask or continuous flow mask; ambient nitrous oxide sensor and gas scavenger apparatus (for removal of exhaled nitrous oxide from room air)

• Degrees of sedative-hypnotic sedation are defined as:

  Anxiolysis (minimal sedation): Consciousness and interactivity are retained; coordination and cognition may be impaired.

  Moderate sedation: Consciousness is depressed; response to verbal requests or touch is retained.

  Deep sedation: Consciousness is depressed; arousal is difficult and may require repeated verbal or painful stimuli; airway patency may decrease; spontaneous breathing may slow.

  General anesthesia: Patient is unconscious and unresponsive to stimuli; respiratory depression or airway compromise is frequent; cardiovascular compromise may occur. General anesthesia is not expected with PSA; however, PSA providers must be able to reverse general anesthesia and provide cardiopulmonary support as needed.

• Capnography is a more sensitive indicator of respiratory depression than oximetry, and, unlike oximetry, remains a reliable indicator when supplemental oxygen is being given.

• Respiratory depression occurs most commonly at the beginning of sedation and during the recovery period after the sedation. Bag-valve-mask ventilation usually suffices for temporary ventilatory support. Airway positioning and nasal or oral airways may be needed to maintain airway patency, particularly if patients have no gag reflex.

• Appropriate scavenging equipment should be used because nitrous oxide had been shown to be a teratogen in animal studies, although epidemiologic studies have not found increased incidence of teratogenicity in humans (5, 6).

• Position the patient recumbent or supine. The patient's head and shoulders should be exposed (to permit observation of breathing) and readily accessible (to permit immediate ventilatory assistance when needed).

PSA should be done, in accordance with institutional guidelines, by a clinician or service proficient with the procedure and with equipment and trained personnel available to provide emergency airway and ventilatory support.

Preparatory tasks

• Select a PSA strategy: A decision to do PSA and the selection of PSA medications to use (including alternative or additional medications) must consider factors such as clinical need, patient risk factors for complications and difficult intubation, and adequacy of provider training and familiarity with PSA medications.

• Ensure the availability of reversal agents as well as PSA medications.

• Ensure the availability of a nearby resuscitation cart, airway suction, and rescue airway equipment.

• Assemble bag-valve-mask and oxygen line, to be able to provide immediate oxygen support, as needed.

• Attach monitoring devices to the patient and verify that they are working correctly.

• Recommended: Begin slow IV infusion (eg, 0.9% saline at 30 mL/h) to ensure IV patency and thereby be able to provide immediate blood pressure support, as needed.

• Before giving PSA medications, establish the patient's pre-sedation vital signs, cardiac rate and rhythm, mental status (level of consciousness), and quality of breathing and ventilation.

Patient monitoring

Monitor the patient throughout PSA, to ensure PSA safety (absence of respiratory depression or cardiovascular compromise) and effectiveness (relief of pain and anxiety):

• Breathing: Continuously assess the state of spontaneous breathing. Changes in the rate, depth, or noise of breathing may precede other signs of respiratory depression.

• End-tidal CO2 (capnography) and O2 saturation (pulse oximetry): Maintain continuous vigilance for hypoventilation. Changes in end-tidal CO2 occur virtually simultaneously with medication-induced hypoventilation and precede hypoxia.

  Respiratory depression due to short-acting PSA medications usually resolves quickly (as the medications wear off).

  If hypoventilation or apnea occurs, provide supplemental oxygen, airway repositioning maneuvers, nasal and oral airways, and bag-valve-mask ventilation as needed. Provide verbal and tactile patient stimulation as needed. If necessary, continue bag-valve-mask ventilation and use appropriate reversal agents. More advanced respiratory support is seldom needed.

• Blood pressure, heart rate, heart rhythm: Frequently check hemodynamics. Transient hypotension may occur, but other cardiovascular events are rare.

  If procedural hypotension occurs, infuse IV fluid as needed to support blood pressure.

• Patient response to verbal and tactile stimuli: Periodically check patient responsiveness, which is used primarily to detect undersedation (insufficient relief of pain and anxiety), not to determine oversedation (which is more efficiently recognized as respiratory depression).

  Do not check patient responsiveness too frequently or aggressively, because doing so can unnecessarily disrupt an effective sedation and possibly incur an additional medication titration. If the patient is calm and pain-free, rely on monitoring of breathing, ventilation, oxygenation, and hemodynamics to ensure the patient's safety during PSA.

Continue patient monitoring until the patient has fully recovered from the sedation.

• Titrate to patient response (sedation) as follows:

  Initial dose: 0.5 to 2 mg IV over ≥ 2 minutes

  Subsequent doses (after 2 to 5 minutes): 0.5 to 2 mg IV doses over ≥ 2 minutes

  Maximum dose: 2.5 mg/dose and 5 mg cumulative IV dose (1.5 mg and 3.5 mg for patients ≥ 60 years of age)

• 5 mg IM (0.1 to 0.15 mg/kg in children). Do not rapidly titrate.

• For children, 0.2 to 0.5 mg/kg intranasally. Do not rapidly titrate.

• Titrate to patient response (mild sedation), as follows:

  Initial dose: 0.02 to 0.1 mg/kg IV over ≥ 2 minutes

  Subsequent doses (after 3 to 5 minutes): 0.005 to 0.025 mg/kg IV over ≥ 2 minutes

  Maximum dose: 2.5 mg/dose and 5 mg cumulative dose (1.5 mg and 3.5 mg for patients ≥ 60 years of age)

• Titrate to patient response (analgesia) as follows:

  Initial dose: 50 to 100 mcg (or 1 mcg/kg) IV

  Subsequent doses: May repeat 50-mcg IV dose every 3 minutes as needed.

• Give supplemental oxygen (eg, nasal oxygen at 2 to 4 liters per minute).

• Titrate doses to patient response (deep sedation), as follows:

  Initial dose: 0.5 to 1.0 mg/kg IV (1.0 to 2.0 mg/kg for children)

  Subsequent doses (after 1 to 3 minutes): 0.25 to 0.5 mg/kg IV every 1 to 3 minutes

  For obese and older patients, start with lower doses. For otherwise healthy adults, start at the higher doses.

• Titrate doses to patient response (deep sedation), as follows:

  Initial dose: 0.1 to 0.15 mg/kg IV

  Subsequent doses: 0.05 mg/kg IV every 3 to 5 minutes

• Give doses over 30 to 60 seconds and titrate to patient response (sedation) as follows:

  Initial dose: 1 to 1.5 mg/kg IV (1 to 2 mg/kg for children) over 1 to 2 minutes

  Subsequent doses (after 10 minutes): 0.5 to 0.75 mg/kg IV (0.5 to 1 mg/kg for children)

  Use lower doses (0.25 to 0.5 mg/kg) depending on the patient's clinical status (eg, older age) or other sedation; however, note that patients may experience partial dissociation and anxiety that is sometimes severe at doses of 0.5 to 1 mg/kg.

• Initial dose: 4 to 5 mg/kg IM

  Subsequent doses 2 to 2.5 mg IM every 10 minutes

• 2 to 10 mg/kg intranasally. Do not rapidly titrate.

PSA using nitrous oxide inhalation

A trained individual is required to administer or supervise nitrous oxide inhalation.

• Assemble gas-delivery and scavenger systems: Select a demand valve mask for a cooperative adult or child > 5 years of age or a continuous flow mask for patients 2 to 5 years of age or who are unable to cooperate.

• Give 100% oxygen for 2 minutes.

• Then switch to a nitrous oxide/oxygen mixture (eg, 40% N2O [N2O 4 L/m and O2 6 L/m]).

• Cooperative patient (self-administered N2O): Instruct the patient to hold the demand valve mask over the face (without strapping it on) and to breathe normally. As the patient becomes drowsy, the mask falls away from the face, the patient will breathe room air, and gas flow from the demand valve mask will stop. When the patient is once again awake or experiencing pain, tell him or her to resume breathing through the mask.

• Uncooperative patient/child (closely supervised N2O administration): Strap a continuous flow mask over the patient's nose and mouth and observe the patient's respirations and sedation level at all times.

• Titrate the gas mixture to provide mild sedation with normal respirations. Prolonged N2O delivery of concentrations > 50% are not typically needed.

• Do not exceed a maximum concentration of 70% N2O to ensure at least 30% O2 to prevent hypoxemia (7).

• When mild sedation is achieved, add an analgesic, sedative, or nerve block as needed for pain control.

• When the procedure is concluded, give 100% O2 for 5 minutes or more, to prevent diffusion hypoxia during recovery.

• Continue dedicated observation of patients until normal wakefulness has returned.

• Do not discharge adult patients until they can walk unaided.

• Do not discharge children until they can sit up unaided and speak at an age-appropriate level.

• Discharge patients accompanied by an adult who will continue observing the patient for post-sedative complications (eg, nausea and vomiting, dizziness, vertigo).

• Do not allow patients to drive themselves home.

• Instruct patients to restrict their activity for 12 hours after PSA (eg, no driving, alcohol, or important decision-making; light meals only).

• Be sure to designate a dedicated observer (eg, appropriately trained nurse, respiratory therapist) whose primary responsibility is to monitor the patient throughout PSA. The operator providing the patient's procedure should not be the dedicated observer.

• Ensure bedside availability of airway equipment. A bag-valve-mask (BVM) usually suffices for temporary ventilatory support.

• Consider avoiding supplemental oxygen if capnography is not available; supplemental oxygen alleviates hypoxemia during respiratory depression, which impedes detection of respiratory depression by pulse oximetry.

• Continue patient monitoring during the recovery period after PSA because respiratory depression, if it occurs, frequently happens soon after the procedure is finished and the pain has ended.

• Adhere to established medication-administration rates; too-slow administration of short-acting medications is common, can delay onset of effective sedation, and risks excessive medication accumulation.

• For subsequent dosing of a medication, frequent smaller doses are preferred over less frequent larger doses to maintain a steady state of sedation.

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1. 1. American Society of Anesthesiologists Task Force on Moderate Procedural Sedation and Analgesia, American Association of Oral and Maxillofacial Surgeons, American College of Radiology, et al: Practice guidelines for moderate procedural sedation and analgesia 2018. Anesthesiology 128:437-479.

2. 2. van der Merwe F, Vickery NJ, Kluyts HL, et al: Postoperative Outcomes Associated With Procedural Sedation Conducted by Physician and Nonphysician Anesthesia Providers: Findings From the Prospective, Observational African Surgical Outcomes Study. Anesth Analg. 2022 Aug 1;135(2):250-263. doi: 10.1213/ANE.0000000000005819. Epub 2021 Dec 28. PMID: 34962901.

3. 3. Beach ML, Cohen DM, Gallagher SM, et al: Major adverse events and relationship to nil per os status in pediatric sedation/anesthesia outside the operating room: A report of the pediatric sedation research consortium. Anesthesiology 124(1):80-88, 2016. doi: 10.1097/ALN.0000000000000933

4. 4. Pergolizzi JV, Webster LR, Vortsman E, et alJ Clin Pharm Therapeutics First published online July 8, 2021. https://doi.org/10.1111/jcpt.13484

5. 5. Zuarez-Easton S, Erez O, Zafran N, et al: Pharmacologic and nonpharmacologic options for pain relief during labor: An Expert review. Expert Rev 228(5 Supplement):S1246-S1259. doi: https://doi.org/10.1016/j.ajog.2023.03.003

6. 6. Fujinaga M: Teratogenicity of nitrous oxide. Best Pract Res Clin Anaesthesiology 15(3):363-375, 2001. https://doi.org/10.1053/bean.2001.0180

7. 7. Huang C, Johnson N: Nitrous oxide, from the operating room to the emergency department. Curr Emerg Hosp Med Rep4:11-18, 2016. doi: 10.1007/s40138-016-0092-3

8. 8. Ferguson I, Bell A, Treston G, et alAnn Emerg Med 68(5): 574-582, 2016. doi: 10.1016/j.annemergmed.2016.05.024 

The following English-language resource may be useful. Please note that The Manual is not responsible for the content of this resource.

Green SM, Roack MG, Krauss BS, et al: Unscheduled procedural sedation: A multidisciplinary consensus practice guideline. Ann Emerg Med 73(5):e51-e65, 2019. doi: 10.1016/j.annemergmed.2019.02.022