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Procedural Skills (SLO6)
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Question 80 of 141
A 29 year old man presents to ED following a rugby injury in which he sustained an anterior shoulder dislocation. You are performing shoulder reduction under procedural sedation using propofol. Which of the following findings would suggest that the patient is under deep sedation?
Answer:
Deep Sedation is a drug-induced depression of consciousness during which patients cannot be easily aroused but respond purposefully following repeated or painful stimulation. The ability to independently maintain ventilatory function may be impaired. Patients may require assistance in maintaining a patent airway, and spontaneous ventilation may be inadequate. Cardiovascular function is usually maintained.Procedural Sedation: Procedure
Pain & Sedation / Procedural Skills (SLO6)
Last Updated: 27th March 2021
Depths of sedation and definitions
Sedation is a continuum which extends from normal alert consciousness to complete unresponsiveness.
| Sedation | Response | Airway reflexes | Ventilatory function | Cardiovascular function |
|---|---|---|---|---|
| Minimal sedation (anxiolysis) e.g. Entonox (Level 1) | Normal response to verbal commands | Maintained | Maintained | Maintained |
| Moderate sedation/analgesia (conscious sedation) e.g. opioids/benzodiazepines (Level 2) | Purposeful response to verbal commands (+/- light stimuli) | Maintained | Usually maintained | Maintained |
| Deep sedation/analgesia e.g. propofol (Level 3) | Not easily aroused but purposeful response to repeated or painful stimuli | May be impaired | May be impaired | Usually maintained |
| General anaesthesia (Level 4) | Patient unrousable, even by painful stimulation | Impaired | Usually impaired | May be impaired |
An important boundary exists between moderate or ‘conscious’ sedation, where the patient responds purposefully to verbal commands, and deeper levels of sedation where the patient responds only to painful stimuli, or not at all. Once verbal contact with the patient is lost it becomes difficult to determine the level of unconsciousness, and over-sedation with an associated risk of airway and cardiorespiratory complications is possible. Deeper levels of sedation are, to all intents and purposes, indistinguishable from general anaesthesia and should therefore be treated as such. Because sedation is a continuum, it is not always possible to predict how the individual patient will respond. Practitioners intending to produce a given level of sedation must therefore be able to ‘rescue’ patients from a deeper level of sedation than intended.
Dissociative sedation: Ketamine is a unique drug in sedation because it causes a dissociative state that does not fit the standard definitions of sedation listed above. Dissociative sedation is defined as ‘a trance-like cataleptic state characterised by profound analgesia and amnesia, with retention of protective airway reflexes, spontaneous respirations, and cardiopulmonary stability'. As there is a loss of verbal contact with patients during ketamine sedation and because significant complications, although rare, can occur unpredictably, ketamine sedation has been grouped with deep sedation/general anaesthesia.
Requirements for ED sedation
- Required minimum staffing levels:
- For minimal sedation with entonox:
- One physician OR emergency nurse practitioner (ENP)
- For all other sedation:
- One physician as sedationist AND
- One physician or ENP as operator AND
- One nurse
- For minimal sedation with entonox:
- Required location and facilities:
- For minimal sedation with entonox:
- Anywhere within the Emergency Department (ED)
- For all other sedation:
- Resuscitation room facilities
- For minimal sedation with entonox:
- Required competencies of sedating practitioner:
- ASA grading
- Pre-procedural assessment including prediction of difficulty in airway management
- Pre-procedural fasting and risk benefit assessment
- Consent and documentation
- Drug selection and preparation: safe use of benzodiazepine/opioid combinations, propofol, and ketamine; intervals between increments and reversal drugs
- Monitoring, complications (e.g. hypoxia, hypotension) and rescue strategies
- Governance and audit
- Required monitoring:
- For minimal sedation with entonox:
- Pulse oximetry
- For all other sedation:
- ECG, NIBP, pulse oximetry
- The use of continuous capnography is recommended for conscious sedation and mandatory for deep and dissociative sedation
- For minimal sedation with entonox:
Fasting prior to ED sedation
- Fasting is not needed for minimal sedation, sedation with nitrous oxide (in oxygen) alone, or moderate sedation where verbal contact is maintained.
- For elective procedures using all other sedation techniques (deep sedation, dissociative sedation and moderate sedation where the patient might not maintain verbal contact with the healthcare professional), apply the fasting rule used for general anaesthesia: two hours for clear fluids and six hours for solids.
- For an emergency procedure in someone who is not fasted, base the decision to proceed with sedation on the urgency of the procedure and the target depth of sedation.
- Careful judgement is required when assessing the risk of aspiration in relation to the urgency of a proposed procedure. The key factors to consider are:
- The urgency of the proposed procedure
- In many life or limb threatening situations (e.g. cardioversion of a cardiac arrhythmia causing significant cardiovascular compromise, or an orthopaedic procedure to correct distal limb ischaemia) the patient is unable to wait and the main question becomes the choice of sedation/ anaesthetic technique rather than the possibility of deferment.
- The proposed depth and duration of sedation
- Longer periods of sedation, greater sedation depth and airway interventions may stimulate airway reflexes (coughing, hiccoughs or laryngospasm) and gastrointestinal motor responses (gagging or recurrent swallowing) leading to gastric distension, regurgitation or vomiting.
- Patient factors
- Conditions such as raised intracranial pressure, hiatus hernia and gastrointestinal obstruction are known to delay gastric emptying, and these patients may be at greater risk. Gastric emptying may also be delayed in patients who have previously undergone upper gastrointestinal surgery, in those recently injured or receiving opioids, and in pregnancy. Morbidly obese patients may be at risk, because the intra-abdominal pressure is higher and the incidence of hiatus hernia is greater than in non-obese patients. The timing of food intake in relation to the injury is also important.
- The urgency of the proposed procedure
- Where the risk of aspiration is significantly increased steps should be taken to mitigate this risk. Suggested approaches include:
- Delaying the procedure, if clinically appropriate.
- Adopting an alternative technique. (Rapid sequence induction of anaesthesia and tracheal intubation is considered the ‘gold standard’ where there is an increased aspiration risk, but pulmonary aspiration may still occur. In addition, RSI introduces other risks, such as inability to intubate or ventilate the patient and the risk of adverse reaction to induction and neuromuscular blocking drugs.)
- Regional anaesthetic techniques may allow the required procedure to be performed with no or minimal sedation.
- Reducing the depth and duration of sedation. This increases the risk of procedural failure, but may be appropriate in some instances.
- Consider whether the administration of ranitidine or proton pump inhibitors, metoclopramide and sodium citrate is appropriate to neutralise gastric acid and promote gastric emptying.
Other considerations for ED sedation
- Oxygen:
- Oxygen should be given to sedated patients, who may experience a fall in oxygen saturation from the baseline level measured on room air. Oxygen should be given from the start of sedative administration until the patient is ready for discharge from the recovery area.
- Capnography
- The use of continuous capnography is mandatory wherever deep sedation, dissociative sedation, general anaesthesia or RSI occurs (i.e. whenever it is anticipated that verbal contact with the patient will be lost), except in rare cases where it would substantially interfere with surgical access.
- Capnography is also recommended at lighter levels of sedation; this is an emerging area of practice, and the use of capnography is expected to become routine.
- Documentation
- Standard forms should be routinely used for patient pre-assessment, patient information, consent, monitoring, discharge information and clinical audit. Past medical history, medications, allergies and physical examination of vital signs, airway and cardiopulmonary status should all be recorded prior to the procedure.
- Whilst the urgency of the clinical situation or patient status may sometimes necessitate treatment in the absence of consent, and in the patient’s best interests, every effort should be made to obtain prior written consent for both the proposed procedure and sedation technique.
Post-procedure monitoring and discharge status
- All patients who have received sedation should continue to be managed in a clinical area that provides the same level of facilities and monitoring as those required during the procedure, until the level of consciousness and other vital signs have returned to pre-procedure baseline levels.
- Patients should be formally assessed for discharge suitability from the clinical area where sedation has taken place.
- Discharge criteria are as follows:
- The patient has returned to their baseline level of consciousness
- Vital signs are within normal limits for that patient
- Respiratory status is not compromised
- Nausea, vomiting, pain and discomfort have been adequately addressed
- If there is a requirement to discharge the patient prior to meeting these criteria they should be transferred to an appropriate clinical environment with continuation of periprocedural monitoring standards.
- Patients meeting discharge criteria following sedation who go on to be discharged home from the Emergency Department should be discharged into the care of a responsible third party. Verbal and written instructions should be given.
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- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
