Comprehensive pre-sedation assessment

A comprehensive pre-sedation assessment is the foundation of safe and effective procedural sedation (PS). It serves as the first line of defense against potential adverse events by identifying patient-specific risk factors and optimizing sedation strategies.

Before proceeding with sedation, clinicians must assess:

✅ Is sedation necessary? Can the procedure be performed without it, or are alternative approaches available?
✅ What is the urgency? Does delaying sedation improve safety without compromising outcomes?

To guide this process, the following key questions should be considered:

• How urgent is the procedure?
• What depth of sedation is required?
• What is the expected procedure duration?
• What is the patient’s risk of adverse events?
• Does the patient have an adequate airway?

Indications for Procedural Sedation

Indications for procedural sedation in the Emergency Department are broad, but some common considerations include:

• Cardioversion
• Fracture/joint reductions
• Complex wound repairs
• Tube thoracostomy
• Lumbar puncture
• Incision and drainage
• Central line placement

Sedation not only enhances patient comfort but also improves procedural success. For instance, children or highly anxious patients may be unable to tolerate certain procedures without adequate sedation, potentially leading to delays, poor procedural outcomes, or increased distress.

The latest ACEP guidelines emphasize structured decision-making, ensuring that PS is used effectively and safely.

Pre-Sedation Assessment:

1. History and Physical exam:

   ✅ Underlying medical conditions (e.g., cardiovascular, respiratory, or neurological disease)
   ✅ Sedation or anesthesia history (e.g., prior adverse reactions, allergies)

2. Evaluate ASA Classification
   • ASA I-II: Generally low risk for procedural sedation
   • ASA III+: Higher risk – requires increased vigilance 
   • Patients classified as ASA III or higher may need careful dose titration or anesthesia consultation for deep sedation.
3. Airway and Ventilation Risk Assessment
   

   Airway evaluation is critical, as PS carries a risk of respiratory compromise. Patients at risk of difficult ventilation or oxygenation require a modified sedation approach to maintain spontaneous breathing.

   • Predictors of difficult airway and ventilation:
     🟢 LEMON Mnemonic – Used to anticipate difficult airway
     🟢 3-3-2 Rule – Identifies limited mouth opening and airway obstruction risk
     🟢 Modified Mallampati Score – Although widely used, ACEP does not recommend it due to limited clinical impact (3,4).

   • Difficult Bag-Mask Ventilation (DMV) Risk Factors:

• • • Age >55
    • BMI >26
    • Bearded
    • Edentulous
    • History of snoring
    • 📌 If a patient has two or more DMV predictors, the risk of airway complications increases significantly (5).

Pre-Procedural Fasting: Myth vs Reality

Aspiration risk during PS is exceedingly rare, and strict fasting protocols are not supported by evidence.

📊 Key Findings:

• Only 9 reported aspiration-related deaths since 1984, 8 of which occurred during upper endoscopy (6).
• No clear evidence suggests that non-compliance with fasting increases aspiration risk.
• 📌 ACEP Guidelines: Recent oral intake is not a contraindication to PS (2).

For high-risk aspiration patients (e.g., OSA, obesity, age <12 months), consider dissociative sedation with ketamine, which:

✅ Preserves airway reflexes
✅ Has no reported cases of aspiration (6,7)

Levels of Sedation: Matching Depth to Procedural Needs

📊 Levels of sedation – Minimal, Moderate, Deep, General Anesthesia

Cappellini I, Piccini GB, Campagnola L, Bochicchio C, Carente R, Lai F, et al. Procedural Sedation in Emergency Department:A Narrative Review. 2024;

📌 Key Concepts:

🔹 Too light – Inadequate pain control, patient movement, procedure failure
🔹 Too deep – Risk of airway loss, respiratory compromise, prolonged recovery

Dissociative Sedation: The Ketamine Advantage

Unlike traditional sedatives, ketamine induces a dissociative state, providing:\

✅ Profound sedation
✅ Maintained airway reflexes & spontaneous breathing
✅ Cardiovascular stability
💡 Why is this important? Dissociative sedation is ideal for procedures requiring deep sedation, while avoiding airway compromise (8).

Choosing the Right Sedation Regime

Since no single agent is perfect for all patients, sedation should be individualized based on:

✅ Procedure type & duration
✅ Patient-specific risks
✅ Need for analgesia vs. anxiolysis

📊 Commonly used sedatives & their properties:

Cappellini I, Piccini GB, Campagnola L, Bochicchio C, Carente R, Lai F, et al. Procedural Sedation in Emergency Department:A Narrative Review. 2024;

Key Considerations:

💉 Propofol – Rapid onset & recovery, but risk of hypotension
💉 Ketamine – Ideal for dissociative sedation; preserves airway reflexes
💉 Etomidate – Hemodynamically stable, but risk of adrenal suppression
💉 Fentanyl/Midazolam – Good for mild/moderate sedation, but can cause respiratory depression

Choosing the right agent maximizes procedural success while minimizing risk

✅ A structured pre-sedation assessment reduces adverse events.
✅ Airway risk assessment is crucial—use LEMON & DMV predictors.
✅ Fasting is not a contraindication to PS per ACEP guidelines.
✅ Ketamine offers a unique advantage for high-risk aspiration patients.
✅ Selecting the appropriate sedative regimen is key to procedural success.

What do you need? (Staff/Stuff/Space)

Successful procedural sedation (PS) requires:
✅ Skilled personnel trained in sedation and airway management
✅ Real-time patient monitoring to detect and manage adverse events
✅ Proper equipment to mitigate complications

1. Sedation Environment

• A monitored setting equipped with oxygen, suction, and resuscitation equipment
• An environment where rapid intervention is possible if complications arise

📌 Key Point: PS should never be performed in unmonitored or resource-limited areas.

• A minimum of two trained healthcare professionals should be present for all procedural sedations:

  • 👨‍⚕️ Sedation Provider (Physician or Advanced Practitioner)

    • Administers PS and monitors depth of sedation

    • Detects and manages physiological changes

    • Possesses airway management and resuscitation skills (e.g., airway repositioning, bag-mask ventilation)

  • 👩‍⚕️ Sedation Monitor (RN or RT)

    • Continuously monitors the patient and documents procedural events

  • Can One Provider Perform Both Roles?

    • Moderate or dissociative sedation: The sedation provider may also perform the procedure if it can be halted immediately in case of an adverse event.

    • Deep sedation: Guidelines traditionally recommend dedicating one provider solely to sedation.

  • 📊 Evidence: A 2006 study of 1,028 procedural sedations across 14 community settings found that when the same provider performed both roles, the adverse event rate was 4.1%, comparable to rates (1-23%) reported in university settings (9).

    📌 Bottom Line: While best practice favors a dedicated sedation provider during deep sedation, evidence suggests that dual-role providers can still maintain safe outcomes in appropriately selected patients.

2. Monitoring During Procedural Sedation

Monitoring is essential for early detection of adverse events and can be divided into two main categories:

• 🧐 Interactive Monitoring (Clinical Observation)
  • Regularly assess sedation depth
  • Monitor response to verbal commands and stimulation
  • Loss of response to stimulation signals deeper sedation than intended
  • Early detection of oversedation allows for rapid intervention before complications arise
  • 📌 Key Concept: The deeper the sedation, the higher the risk of airway loss and respiratory/cardiovascular depression.

• 📊 Physiologic Monitoring

  • Cardiac Monitoring – Detects bradycardia and arrhythmias
  • Blood Pressure Monitoring – Frequent checks, especially in high-risk patients
  • Pulse Oximetry – Detects oxygen desaturation in real time
  • Capnography (End-Tidal CO₂ Monitoring):
    • ✅ More sensitive than pulse oximetry for detecting hypoventilation and apnea
      • ✅ Reduces the risk of unrecognized hypoxia
  • 📌 Tip: Apply once the patient is adequately sedated if they are initially uncooperative

💡 For more on capnography, see Dr. Nick Choi’s post on the topic!

3. Supplies

• 🫁 Supplemental Oxygen
• ✅ High-flow oxygen can delay desaturation by:
  • 6 minutes in adults
  • 2-4 minutes in children
  • ⚠ Caution: Avoid using oxygen alone without capnography, as it may mask hypoventilation (i.e., CO₂ retention despite normal SpO₂).
• 🧴 Reversal Agents (Antidotes)
  • ✅ Flumazenil – Reverses benzodiazepines
  • ✅ Naloxone – Reverses opioids
  • 📌 Keep these readily available in case of oversedation.
• 🛠️ Advanced Airway & Resuscitation Equipment
  • ✅ Bag-mask ventilation setup
  • ✅ Supraglottic airways (e.g., LMA)
  • ✅ Intubation equipment for severe respiratory compromise
  • 🚨 Always be prepared for a potential airway emergency.

4. Post Sedation Monitoring and Recovery

• Monitoring does not end when the procedure is over! Patients should be observed until they:
  • ✅ Return to baseline mental status
  • ✅ Have stable vital signs
  • ✅ No longer have a risk of airway compromise
• 🏠 When Can a Patient Be Discharged? ACEP guidelines state that:
  • Patients do not need to tolerate oral intake before discharge
  • Driving post-sedation is not formally contraindicated but requires clinical judgment
  • 📌 Final Check: Ensure patients are fully alert with adequate motor function before sending them home.

Managing Adverse Events in Procedural Sedation

While procedural sedation (PS) is generally safe, it is not without risk. Adverse events can occur across four primary systems:

• Respiratory – Hypoxia, apnea, laryngospasm
  • Key Concept: Nearly all sedative agents can cause dose-dependent respiratory depression.
  • 📌 Prevention & Management:
  • ✅ Preoxygenate to increase apnea tolerance
  • ✅ Use capnography to detect early hypoventilation
  • ✅ Bag-mask ventilation (BMV) for transient respiratory depression
  • ✅ Be prepared for airway intervention in high-risk patients

• Cardiovascular – Hypotension, bradycardia
  • 💡 Significant hypotension and bradycardia are rare but can occur in:
  • Patients with cardiac disease
  • Patients on beta-blockers or other cardio-depressant medication
  • 📌 Management
  • ✅ Monitor BP frequently, especially in volume-depleted patient
  • ✅ Consider pre-sedation IV fluids if feasibl
  • ✅ Use hemodynamically stable agents (e.g., ketamine, etomidate) in high-risk patients

• Neurological – Oversedation, delirium
  • Oversedation is the most common neurological adverse event.
  • 📌 Management:
  • ✅ Adjust sedative dosing as needed
  • ✅ Use reversal agents (flumazenil for benzodiazepines, naloxone for opioids) if necessary
  • ✅ Monitor patients post-procedure until alert and oriented

• Gastrointestinal – Nausea, vomiting, aspiration
  • 📊 Evidence:
    • Routine prophylactic antiemetics are not strongly supported by evidence.
    • Ondansetron has been shown to reduce vomiting in pediatric patients receiving ketamine
    • 📌 Recommendations:
    • ✅ Consider prophylactic ondansetron in pediatric patients or those at high risk of vomiting
    • ✅ Monitor for aspiration risk, especially in high-risk populations (e.g., OSA, obesity, pregnancy)

Special Populations in Procedural Sedation

Pediatrics

• Risk Factors
  • Airway differences – Increased risk of obstruction, laryngospasm
    • Congenital abnormalities such as Pierre Robin syndrome present high-risk airways and should prompt consultation with a pediatric anesthesiologist.
  • Immature protective reflexes – Higher sensitivity to sedatives
    • Children under 6 years of age exhibit greater airway vulnerability, less matured protective airway reflexes, and greater sensitivity to sedatives affecting respiratory drive compared to older children (12).
  • Younger children may experience deeper-than-intended sedation
    • Infants under 6 months of age exhibit slower drug clearance, decreased protein binding, increased blood-brain barrier permeability, and lower lean body mass ration, predisposing them to altered pharmacokinetics and increased drug sensitivity (11).

Anatomical and Physiological Differences in in Pediatrics (adopted from Walls et al., 2023 (22).

• 📊 Key Study:
  • A 2017 multicenter observational study examined 6,295 children undergoing PS in Canadian EDs:
  • Adverse event rate: 11.7%
  • Desaturation: 5.6%
  • Vomiting: 5.2%
  • Ketamine alone was associated with the lowest rates of serious adverse events (13).
    • Although rare, laryngospasm is a potentially life-threatening complication in pediatric populations.
      • A study reported an incidence of 3.3 events per 1000 sedations in a cohort of 270,000 pediatric sedations over 7 years with the greatest predictors of laryngospasm to be (14):
        • Higher ASA class.
        • Presence of URTI.
          
• 📌 Recommendations:
  • ✅ Use single-agent sedation (e.g., ketamine) when possible
  • ✅ Consider pre-treatment with ondansetron to reduce post-sedation vomiting
  • ✅ Opioid use increases adverse event risk—use judiciously
  • ✅ Fasting is NOT a predictor of aspiration risk in pediatrics

Geriatrics

• Older adults are at higher risk during PS due to:
  • Increased comorbidities
  • Greater sensitivity to sedatives
  • Slower drug clearance and prolonged sedation
• 📌 Recommendations:
  • ✅ Use smaller per kg dosing to avoid oversedation
  • ✅ Increase dosing intervals to prevent cumulative effects
  • ✅ Preoxygenate to mitigate risk of hypoxia

Bariatrics

• Physiological Considerations:
  • ↓ Lung capacity, ↑ oxygen consumption → More frequent airway interventions
  • ↑ CO₂ retention → Higher risk of hypoventilation
  • Obese patient frequently suffer from associated health problems such as sleep apnea and restrictive lung disease which leads to more frequent airway interventions (e.g., bag-mask ventilation) and short episodes of hypoxemia, but it does not significantly raise the risk of severe adverse outcomes (17).
  • The decreases ratio of lean body mass in obese patients alters both pharmacodynamics and pharmacokinetics, necessitating careful attention to medication dosing.
• 📌 Recommendations:
  • ✅ Use lean/ideal body weight (LBW) for medication dosing
  • ✅ Anticipate and prepare for airway interventions

Pregnancy

• Key Considerations:
  • Pregnancy-related physiological changes impact sedation management
  • Fetal considerations must be factored into decision-making
  • Pregnancy-Related Physiological Changes:
    • ↑ Cardiac output (CO), ↓ Functional residual capacity (FRC), ↑ Oxygen consumption
    • Dilutional anemia → Increased risk of hypotension
• 📌 Recommendations:
  • ✅ Standard fasting guidelines apply—pregnancy alone is NOT an aspiration risk unless in active labor (18).
  • ✅ Left lateral decubitus (LLD) positioning in 2nd & 3rd trimesters (15° tilt) to prevent hypotension and fetal hypoxia (19).
  • ✅ Fetal heart rate monitoring before and after PS—continuous monitoring if pregnancy is beyond term or complicated (20).
  • ✅ High-flow oxygen to prevent maternal hypoxia (21).
  • ✅ Consult obstetrics in high-risk cases.

References

1. Khan MT, Khan AR, Rohail S, Raza FA, Ahmed S, Siddiqui A, et al. Safety of procedural sedation in emergency department settings among the adult population: a systematic review and meta-analysis of randomized controlled trials. Intern Emerg Med. 2024 Aug;19(5):1385–403.
2. Green SM, Roback MG, Krauss BS, Miner JR, Schneider S, Kivela PD, et al. Unscheduled Procedural Sedation: A Multidisciplinary Consensus Practice Guideline. Ann Emerg Med. 2019 May;73(5):e51–65.
3. Lee A, Fan LTY, Gin T, Karmakar MK, Ngan Kee WD. A Systematic Review (Meta-Analysis) of the Accuracy of the Mallampati Tests to Predict the Difficult Airway: Anesth Analg. 2006 Jun;102(6):1867–78.
4. Iyer M, Pitetti R, Vitale M. Higher Mallampati Scores Are Not Associated with More Adverse Events During Pediatric Procedural Sedation and Analgesia. West J Emerg Med. 2018 Mar 5;19(2):430–6.
5. Langeron O, Bianchi A. Prediction of Difficult Mask Ventilation. 2000;92(5).
6. Green SM, Mason KP, Krauss BS. Pulmonary aspiration during procedural sedation: a comprehensive systematic review. Br J Anaesth. 2017 Mar;118(3):344–54.
7. Green SM, Roback MG, Kennedy RM, Krauss B. Clinical Practice Guideline for Emergency Department Ketamine Dissociative Sedation: 2011 Update. Ann Emerg Med. 2011 May;57(5):449–61.
8. Cappellini I, Piccini GB, Campagnola L, Bochicchio C, Carente R, Lai F, et al. Procedural Sedation in Emergency Department:A Narrative Review. 2024;
9. Hogan K, Sacchetti A, Aman L, Opiela D. The safety of single-physician procedural sedation in the emergency department. Emerg Med J. 2006 Dec 1;23(12):922–3.
10. Langston WT, Wathen JE, Roback MG, Bajaj L. Effect of Ondansetron on the Incidence of Vomiting Associated With Ketamine Sedation in Children: A Double-Blind, Randomized, Placebo-Controlled Trial. Ann Emerg Med. 2008 Jul;52(1):30–4.
11. Ku LC, Smith PB. Dosing in neonates: special considerations in physiology and trial design. Pediatr Res. 2015 Jan;77(1):2–9.
12. Dial S, Silver P, Bock K, Sagy M. Pediatric sedation for procedures titrated to a desired degree of immobility results in unpredictable depth of sedation: Pediatr Emerg Care. 2001 Dec;17(6):414–20.
13. Bhatt M, Johnson DW, Chan J, Taljaard M, Barrowman N, Farion KJ, et al. Risk Factors for Adverse Events in Emergency Department Procedural Sedation for Children. JAMA Pediatr. 2017 Oct 1;171(10):957.
14. Cosgrove P, Krauss BS, Cravero JP, Fleegler EW. Predictors of Laryngospasm During 276,832 Episodes of Pediatric Procedural Sedation. Ann Emerg Med. 2022 Dec;80(6):485–96.
15. Ben-Yakov M, Bhatt M. Emergency procedural sedation in children. Can Med Assoc J. 2020 Oct 5;192(40):E1162–E1162.
16. Eldawlatly AA, Delvi MB, Ahmad A. Procedural sedation analgesia in the elderly patient. Saudi J Anaesth. 2023 Oct;17(4):533–9.
17. Bautista A, Hrushka L, Lenhardt R. Procedural sedation in the morbidly obese: implications, complications, and management. Int Anesthesiol Clin. 2020;58(3):41–6.
18. Dean G, Jacobs AR, Goldstein RC, Gevirtz CM, Paul ME. The safety of deep sedation without intubation for abortion in the outpatient setting. J Clin Anesth. 2011 Sep;23(6):437–42.
19. Lee SWY, Khaw KS, Ngan Kee WD, Leung TY, Critchley LAH. Haemodynamic effects from aortocaval compression at different angles of lateral tilt in non-labouring term pregnant women. Br J Anaesth. 2012 Dec;109(6):950–6.
20. ACOG Committee Opinion No. 775: Nonobstetric Surgery During Pregnancy. Obstet Gynecol. 2019 Apr;133(4):e285–6.
21. Neuman G, Koren G. Safety of Procedural Sedation in Pregnancy. J Obstet Gynaecol Can. 2013 Feb;35(2):168–73.
22. Walls RM, Hockberger RS, Gausche-Hill M, Erickson TB, Wilcox SR. Rosen’s emergency medicine : concepts and clinical practice [Internet]. Tenth edition. Philadelphia: Elsevier; 2023. Available from: https://www.clinicalkey.com/dura/browse/bookChapter/3-s2.0-C20181032357