Risk stratification identifies patients who are at risk of sedation-related adverse events so they can be referred to a more highly specialised sedation provider.
Risk stratification focuses on the degree of sedation required and may be unnecessary for procedures performed with mild sedation. Find more information in the Safe Procedural Sedation Matrix.
In higher volume services, a dedicated person will provide screening to enable safe and efficient care.
The screener will alert clinical staff when patients do not meet the agreed criteria for non-anaesthetist procedural sedation. This should then be followed up with a nominated contact within the department of anaesthesia for advice and referral.
Levels of sedation
Sedation depth is determined by the patient’s clinical response, not solely by the drug, dose or route of administration. Sedation is a continuum, and patients may progress unpredictably to a deeper level than intended. The clinician responsible for sedation must be able to recognise this progression and initiate appropriate rescue.
Mild sedation: a drug-induced state of diminished anxiety, during which patients are conscious and respond purposefully to verbal commands or light tactile stimulation. Common agents include nitrous oxide, methoxyflurane or oral anxiolytics.
Moderate sedation: a drug-induced state of depressed consciousness during which patients retain the ability to respond purposefully to verbal commands and tactile stimulation. Common agents include intravenous opioids, benzodiazepines, or small hand boluses of propofol.
Deep sedation: a drug-induced state of depressed consciousness during which patients are not easily roused and may respond only to noxious stimulation. Common agents include propofol administered via continuous infusion, including target-controlled infusion techniques.
Intentional deep sedation should only be administered by anaesthetists, critical care providers (CCPs) or other medical practitioners who are appropriately trained, credentialed and authorised to provide deep sedation, and who are able to recognise and manage unintended progression to general anaesthesia, including airway and cardiorespiratory complications.
Flag system
A flag system can be used to alert staff to higher risk patients.
Red flags represent the highest risk for procedural sedation. They indicate a contraindication to sedation performed without specialised anaesthesia or CCP. Patients should be carefully evaluated for red flags and, if any are identified, they should be referred to anaesthesia- or CCP-led sedation.
Red flag criteria differ for mild sedation and moderate sedation. In moderate sedation, there is a risk of unplanned deep sedation. As a result, risk for airway obstruction and aspiration risk must be considered.
Orange flags represent patients at increased risk and should be identified before episodes of moderate sedation. The presence of a greater number of orange flags represents an additive patient risk for sedation.
Local policies should determine what happens when multiple orange flags are identified. For example, the presence of three orange flags may mean that sedation is performed by an anaesthesia or CCP provider. At a minimum, patients with multiple orange flags should be discussed with a nominated contact at the department of anaesthesia for advice and consideration for referral.
Stratification
Consider depth of sedation and orange and red flags when assessing risk.
Example risk assessments are available on the Safe Procedural Sedation SharePoint site. Email ACI-Anaesthesia@health.nsw.gov.au to request access.
Anaesthesia or CCP-led sedation should be strongly considered for:
- planned deep sedation
- procedures > 60 minutes
- procedures with prolonged moderate or severe discomfort
- uncomfortable positioning during procedure
- previously failed sedation
- patients in whom benzodiazepines or opioids are contraindicated
- uncooperative patients
- patients unable to lie flat or remain still for the procedure.
The pre-sedation risk assessment and decision guidance provides an example of how risk assessment can be undertaken, to take both depth of sedation and orange or red flags into consideration.
Red flags for mild sedation:
- Threatened airway
- Respiratory failure, hypoxia or oxygen dependence
- Haemodynamically unstable
- Ongoing haemorrhage
- Increased susceptibility to sedative medications
- Decreased level of consciousness
- Severe neurological or neuromuscular disease
Note: severe refers to the degree of functional limitation associated with a condition (e.g. the presence of shortness of breath at rest or difficulty walking unaided) and does not necessarily indicate end-stage disease.
Red flags for moderate sedation:
- Threatened airway
- Respiratory failure, hypoxia or oxygen dependence
- Haemodynamically unstable
- Ongoing haemorrhage
- Increased susceptibility to sedative medications
- Decreased level of consciousness
- Severe neurological or neuromuscular disorder
- Severe frailty (Clinical Frailty Scale score of ≥ 7)
- Severe cardiac disease
- Severe respiratory disease
- High airway obstruction risk (complex airway anatomy, e.g. BMI ≥ 45)
- High aspiration risk (oesophageal, gastric or bowel obstruction)
Note: severe refers to the degree of functional limitation associated with a condition (e.g. the presence of shortness of breath at rest or difficulty walking unaided) and does not necessarily indicate end-stage disease.
Orange flags:
Patient factors
- Moderate frailty (Clinical Frailty Scale score of ≥ 6)
- Pregnancy (refer to local guidelines)
- Significant anxiety (personal anxiety preventing procedure to proceed)
- Chronic kidney disease (stage 4 or dialysis)
- Severe liver disease
Procedural factors
- Procedure duration > 60 minutes
- Shared airway procedure
- Prior sedation or anaesthesia related adverse events
Airway obstruction risk
- BMI > 35–44
- Moderate to severe OSA, STOP-BANG ≥ 5 or on CPAP
Aspiration risk
- Severe reflux
- Gastroparesis
- GLP-1 agonists