Assessment

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Sedation is safest for healthy patients. The pre-sedation assessment determines a person’s suitability for sedation and the depth of sedation needed.

Pre-sedation screening identifies patients whose health status means they may need more highly specialised sedation providers. A patient’s health status for anaesthesia is determined by a risk assessment in combination with their American Society of Anesthesiologists (ASA) score.

Typically, the risk assessment is performed by the procedural sedation provider or a suitably trained clinician acting under their supervision.

Assessment factors

Pre-sedation risk assessment takes into account the intended depth of sedation (mild, moderate or deep), as well as patient, airway and procedural factors.

Patient factors

  • Age1
  • Weight1
  • Significant cardiac or respiratory disease (limited cardiorespiratory reserve)
  • Significant neurological or neuromuscular disease (increases susceptibility to sedative medications)
  • Frailty (increases susceptibility to sedative medications)
  • Medications (especially anti-thrombotic and diabetic)1
  • Allergies, especially to sedative or analgesic medications1,2
  • Prior complications with procedural sedation or anaesthesia1,3-5
  • Potential for pregnancy6
  • Aboriginality

Airway factors

  • Risk of airway obstruction, e.g. airway abnormalities, severe obesity, sleep apnoea1,5,6
  • Risk factors for aspiration, including oesophageal and gastric or bowel obstruction, reflux, delayed gastric emptying or medications which delay gastric emptying, e.g. glucagon-like peptide-1 receptor agonists

Procedural factors

  • Intended depth of sedation – mild, moderate or deep
  • Procedure duration (moderate risk if >60 minutes, high risk if >120 minutes)
  • Pain or discomfort of procedure
  • Shared airway procedures, e.g. endoscopy
  • Prior failed sedation or complications with anaesthesia
  • Need for immobility
  • Uncomfortable positioning, e.g. prone

For planned procedures, complete assessments before the day of the procedure. This allows time to identify the patient’s needs, provide instructions and organise any required referral for anaesthesia or physician-led sedation.

ASA score

The ASA score is a global tool for classifying the physical status of the patient. It is also referred to as ASA-PS.

Every patient undergoing sedation should have an ASA score attributed to them by the person conducting the risk assessment.

Every sedation provider should know the patient’s ASA score if providing moderate or deep levels of sedation.

Patients with an ASA score of 1 or 2 are considered healthy.7 Risk increases exponentially with increasing ASA score.

ASA 1: a normal healthy patient

ASA 2: a patient with mild systemic disease

ASA 3: a patient with severe systemic disease

ASA 4: a patient with severe systemic disease that is a constant threat to life

ASA 5: a patient who is not expected to survive.8

References

  1. Australian and New Zealand College of Anaesthetists. PG09(G) Guideline on procedural sedation 2023. Melbourne, Australia: ANZCA; 2023 [cited 5 December 2024].
  2. Dobson G, Chong MA, Chow L, et al. Procedural sedation: a position paper of the Canadian Anesthesiologists' Society. Can J Anaesth. 2018;65(12):1372-84. DOI: 10.1007/s12630-018-1230-z
  3. Tran TT, Beutler SS, Urman RD. Moderate and deep sedation training and pharmacology for nonanesthesiologists: recommendations for effective practice. Curr Opin Anaesthesiol. 2019;32(4):457-63. DOI: 10.1097/aco.0000000000000758
  4. Green SM, Roback MG, Krauss BS, et al. Unscheduled Procedural Sedation: A Multidisciplinary Consensus Practice Guideline. Ann Emerg Med. 2019;73(5):e51-e65. DOI: 10.1016/j.annemergmed.2019.02.022
  5. Uí Bhroin S, Kidney E, Sabbagha H, et al. Procedural Sedation of Adults in the Emergency Department [v1.0]. Irish Association for Emergency Medicine (IAEM); 2022.
  6. Practice Guidelines for Moderate Procedural Sedation and Analgesia 2018: A Report by the American Society of Anesthesiologists Task Force on Moderate Procedural Sedation and Analgesia, the American Association of Oral and Maxillofacial Surgeons, American College of Radiology, American Dental Association, American Society of Dentist Anesthesiologists, and Society of Interventional Radiology. Anesthesiology. 2018;128(3):437-79. DOI: 10.1097/aln.0000000000002043
  7. Kim SH, Moon YJ, Chae MS, et al. Korean clinical practice guidelines for diagnostic and procedural sedation. Korean J Anesthesiol. 2024;77(1):5-30. DOI: 10.4097/kja.23745
  8. American Society of Anaesthesiologists. Statement on ASA Physical Status Classification System. Washington D.C., United States: ASA; 2020 [cited 12 February 2025].
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