Propofol for Procedural Sedation in Adults

Context

Propofol (2-6 di-isopropylphenol) is a short acting hypnotic agent, which induces sedation in lower doses, and general anaesthesia in higher doses. It is one of the most commonly used anaesthetic drugs in the world.

The pharmacokinetics of propofol are complex, but typically it has a rapid onset of action causing an effect within one arm-brain circulation (generally under a minute), and rapid offset due to redistribution into tissues following a single bolus (generally in under 10 minutes). Repeated boluses or an infusion will lead to a prolonged duration of action.

The effects of propofol vary widely between individuals. Generally, patients who are older, sicker or intoxicated with other depressant drugs will have a more pronounced response to propofol. Younger patients or those with a background of alcohol dependence generally require higher doses to achieve the same effect.

Propofol has no analgesia effects, so when being used for procedural sedation it is often given with a short acting opioid, such as fentanyl, which will potentiate its effect. An alternative is to co-administer ketamine (“ketofol”), a practice that has both proponents and detractors, and is outside the scope of this module.

The key to safe use of propofol for procedural sedation in the emergency department is careful titration – you can always give more, but once given you cannot take it away!

The use of propofol for procedural sedation in emergency medicine was first reported in 1995. [1] Studies have since demonstrated a safety profile equivalent to benzodiazepine/opiate combinations. [2] Its safe use by emergency physicians has been established [3] and promoted. [4] The Royal College of Emergency Medicine (RCEM, with the support of the Royal College of Anaesthetists (RCoA) endorses the use of propofol by trained emergency physicians. [5, 6]

Sedation Definitions

The RCoA and CEM sedation definitions are as follows:

Moderate sedation/analgesia (“conscious sedation”)

This is a drug-induced depression of consciousness during which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation. No interventions are required to maintain a patent airway, and spontaneous ventilation is adequate. Cardiovascular function is usually maintained. In the ED this is most often achieved using a combination of opioids and benzodiazepines.

Deep sedation/analgesia

This 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.

Indications

Sedation with propofol might be particularly suitable in the following procedures:

Large Joint Relocation

Propofol may have a role in the relocation of any large joint, particularly where attempts with Entonox or Penthrox have been unsuccessful.

In principle, successful relocation of such a large joint (and its associated large muscle groups) requires brief deep sedation, for which propofol is ideal. For a dislocated prosthetic hip joint, non-randomised studies demonstrate success rates of nearly 100% using propofol [8, 9] versus 66% using benzodiazepine/opiate combinations. [10]

Propofol can be titrated to effect, and repeated doses can be given to prolong the duration of action.

Fracture Management

Similarly, propofol may have a role in sedation patients to manipulate a fracture, especially those where a regional anaesthetic technique such as haematoma block cannot be performed, and attempts using Entonox or Penthrox have not been successful.

One disadvantage of using propofol for fracture management (as opposed to a regional anaesthetic technique) as the patient must generally recover from the sedation in order to leave the resuscitation area and have imaging to confirm a successful reduction. As a result, repeated sedation may be required if the first reduction attempt was unsuccessful, whereas a regional block may still be working.

(Synchronised) DC cardioversion in cardiovascularly ‘stable’ patients

DCCV is an unpleasant procedure, but is only very briefly painful – the rapid onset/offset and hypnotic and amnesic effects of propofol make it a potentially useful sedative agent for patients undergoing DCCV, provided they are not cardiovascularly compromised.

Counter-indications

Important adverse effects of propofol include:

• Loss of upper airway tone leading to airway obstruction;
• Loss of protective airway reflexes, leading to aspiration in the event of regurgitation of gastric contents;
• Hypoventilation or apnoea leading to hypoxia;
• Vasodilatation and myocardial depression leading to hypotension, which may be profound.

Propofol should therefore be avoided, or used with extreme caution, in:

• Patients who are likely to be difficult to ventilate using a facemask, and/or intubate if required;
• Elderly patients, particularly frail elderly patients or those taking antihypertensives, who are at increased risk of hypotension;
• “Sick patients” such as those who are hypoxic or hypotensive due infection;
• Frail patients, or ASA III/IV patients;
• Obese patients, who may have altered pharmacokinetics and pharmacodynamics, may be difficult to ventilate, and are at increased risk of aspiration;
• Patients who are pregnant, who may also have altered pharmacokinetics and pharmacodynamics, and are at increased risk of difficult ventilation and aspiration;
• Patients who are not adequately fasted;
• Patients with a known or suspected allergy to soy or eggs (propofol is presented in an emulsion which contains 10% soybean oil and 1% egg phospholipid).

Onset of action

It should be noted that patients with reduced cardiac output (due to increasing age or frailty, or intercurrent illness) will have a prolonged arm-brain circulation time. It may therefore take longer for an effect to be seen after a single bolus of propofol is given. Inexperienced practitioners may give further boluses before the first has had effect, leading to potential overdose with higher risk of apnoea and hypotension. With these patients therefore, it is important to give small boluses, and give plenty of time for them to take effect.

Fasting

Fasting deserves further mention, given that the link between aspiration and the fasting state of the patient is controversial. A comprehensive review of the emergency procedural sedation literature found no evidence of a significant aspiration risk with procedural sedation. [12] Nevertheless, for those patients who have recently eaten or drunk, it remains good practice to carefully weigh up the risks/benefits of sedation, particularly in vulnerable patients (see below), and consider other options.

Patients who are particularly at risk of aspiration include:

• Those who have a hiatus hernia;
• Those with gastrointestinal obstruction;
• Those who are pregnant;
• Those who are morbidly obese.

Alternatives to propofol

Alternatives to propofol sedation in the emergency department include:

• Use of local anaesthetic, haematoma block, Bier’s block or other regional technique;
• Use of Penthrox or Entonox;
• Use of other sedative agents such as ketamine;
• Referral to specialty, such that the procedure can be performed in theatre with anaesthetic support;
• Delaying the procedure (for example, to prolong fasting time);
• Not performing the procedure at all.

Learning Bite

Identify ‘at risk’ patients and consider alternative strategies.

A Suggested Protocol

RCEM has published guidance on the use of procedural sedation in the emergency department. Please also refer to your own department’s sedation policy prior to performing sedation.

An example protocol is as follows:

• Perform a focussed assessment, with emphasis on current medications and allergies, airway, fasting status, and any previous adverse experience or reactions with sedation or anaesthesia.
• Consider the indication for propofol sedation, and alternate strategies that may be employed. It is important not only to consider the individual patient, but also the wider department – are resources currently available to deliver sedation safely?
• Consent the patient for sedation. Explain the procedure, the rationale for the use of sedation, and any alternative strategies that could reasonably be used. It is important to inform the patient that they will not be able to drive for 24 hours post sedation. It is also important to inform them of the risks of awareness/recall of the procedure being performed, post-sedation drowsiness and nausea, drug reaction, aspiration and the (very rare) requirement for intubation and ventilatory support.
• Move the patient to the resuscitation area. They should be made comfortable on a trolley. Raising the head of the bed may help to protect against passive regurgitation of gastric contents (and therefore aspiration) whilst improving V/Q matching (and thus protecting against hypoxia), though at an increased risk of cerebral hypoperfusion if hypotension develops.
• Gain and secure good IV access.
• Identify staff: one seditionist, one proceduralist, and at least one other staff member to act as a runner/scribe.
• Check that appropriate equipment is available, including (but not necessarily limited to) working suction, facemask and Mapleson C circuit, airway adjuncts and intubation equipment.
• Draw up appropriate drugs (propofol +/- opioid). If hypotension is likely, consider a bolus of fluid prior to sedation, and make sure that a vasopressor such as metaraminol is quickly available. Staff should be aware of the location of emergency drugs, including muscle relaxant, should they be required.
• Apply high flow oxygen via a non-rebreathe mask, and monitoring (SaO2, ECG, NIBP and capnography).
• Give sedative drugs. Propofol should be carefully titrated to effect. It is recommended to give an initial bolus of 0.5 – 1mg/kg (typically 50mg) in younger patients, and under 0.5mg/kg (typically 20mg) in older/frail patients, and then supplementary boluses of 10 – 20mg until the desired level of sedation is achieved.
• The proceduralist should perform the procedure whilst the sedationist continually monitors the patient, providing further boluses of sedation if needed. The total amount of propofol that may be required can vary widely, from just 10 – 20mg to well over 300mg!
• Following completion of the procedure, the patient should be allowed to wake to full consciousness before oxygen and monitoring is removed and they leave the resuscitation area.

Assessing a patient’s airway

• Is my patient able to position their head in the ‘sniffing the morning air’ position – meaning can they move their head forward in relation to their chest, and extend their head in relation to their neck?
• Is my patient able to open their mouth widely (so that an oropharyngeal airway can be inserted)?
• Is my patient able to protrude their bottom incisors in front of their top (suggesting they could accommodate a suitably sized oropharyngeal airway)?
• Does my patient have any features that may make facemask ventilation difficult, such as facial hair or retrognathia?

Remember the acronym LEMON

• Look for features that make facemask ventilation difficult, such as obesity, beards or cachexia.
• Evaluate using the “332” rule
• Mallampati grade
• Obstruction due to upper airway anatomical abnormality
• Neck movement

Hypoxia

Precautions taken to minimise the risk of hypoxia are:

• Careful patient selection
• Having the patient sat up
• Preoxygenation
• Carefully titrated propofol
• Reduced dose(s) for the elderly

Should hypoxia occur:

• Ask the proceduralist to begin the procedure if they have not done so already – the stimulation may result in a rapid improvement in respiratory effort;
• Open the airway with a jaw thrust, which may improve respiratory effect and oxygenation by itself;
• Provide facemask ventilation using a Mapleson C circuit if ventilatory effort remains poor or absent in spite of an open airway.

If facemask ventilation is not effective, call immediately for help. Effective pre-oxygenation can prevent hypoxia in an apnoeic patient for a surprisingly long time, but when oxygen saturations begin to fall they may fall precipitously. Consider the need for an airway adjunct, and prepare for intubation.

Hypotension

Precautions taken to minimise the risk of hypotension are:

• Careful patient selection
• Fluid bolus pre-procedure
• Titrated propofol and a reduction in dose for the elderly

The strategies to correct hypotension would be:

• Further fluid bolus
• Consider elevating the legs whilst maintaining a sitting up position
• Consider the use of vasopressors e.g. 0.5 mg boluses of metaraminol

The patient should not leave resus until:

• They are spontaneously alert;
• Vital signs are normalised, and supplementary oxygen is not required;
• Pain and nausea (if present) are controlled;
• The sedation has been documented and any drugs used have been prescribed and signed for.

If being discharged home, the patient should not leave the emergency department until:

• At least two hours have elapsed since any reversal agent (flumazenil, naloxone), if used, was given.
• They have been able to drink water (and eat if appropriate);
• They have safely mobilised (if appropriate);
• They have passed urine (if appropriate).

The patient should be discharged into the care of a responsible adult, who should be with them for the next 24 hours. The patient must not drive for 24 hours post sedation. Written advice should be given. [5]

Governance issues include:

Training

Sadly, research and audit have continually identified avoidable morbidity and mortality from sedation. The most common recurring theme is the lack of formal training for the appropriate administration of sedative drugs and prompt recognition and treatment of sedation-related complications.

Given that deeper levels of sedation are indistinguishable from general anaesthesia, you should have the knowledge and skills to manage and rescue a patient from general anaesthesia. The College requires you to have successfully completed the Initial Assessment of Competence of the Royal College of Anaesthetists and have been accredited through a local training programme. [5]

The latter includes training in:

• 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: benzodiazepine/opioid combinations, intervals between increments and reversal drugs
• Monitoring, complications (e.g. hypoxia and hypotension) and rescue strategies
• Governance and audit
• Drug selection with emphasis on potential alternative strategies and/or lighter sedation
• Safe use of propofol

Learning Bite

If you are using propofol for sedation, you should be comfortable that your skills include managing general anaesthesia.

Documentation

You should document patient evaluation, consent, data from monitoring during and after sedation and readiness for discharge. A dedicated, electronic, password-protected database is helpful. In addition, consider prospective use of an audit tool produced by an international consensus. [13]

Risk management

Ensure that the environment in which you use propofol includes the following facilities:

• Full resuscitation equipment for the administration of basic and advanced life support. Equipment and drugs should be checked daily, and after each use – that such checks have occurred should be routinely recorded.
• Difficult airway equipment
• Continuous high flow oxygen with appropriate devices for administration
• High pressure suction with appropriate suction catheters
• A trolley capable of being tipped head down
• Monitoring: Pulse oximeter, ECG, NIBP and continuous quantitative capnography
• Appropriate range of intravenous cannulae
• An appropriate range of intravenous fluids and infusion devices
• Manual handling devices

Audit process

To ensure appropriate governance of sedation within an institution, RCEM recommend a sedation committee and a nominated lead clinician for sedation. [6]

The TROOPS reporting tool [13] for adverse events should be considered as it focusses both on significant interventions (e.g., positive pressure ventilation) and outcomes (e.g. unplanned admission to hospital) without the need to define events in terms of ‘threshold’ or ‘duration’ which are often subject to clinician disagreement. It should be noted that often certain interventions (e.g., airway re-positioning) are an accepted part of PS and their performance does not necessarily signify a clinical error.

Learning Bite

There should be routine and transparent audit of your departmental sedation practice.

1. Swanson ER, Seaberg DC, Stypula RW, Troianos CA. Propofol for conscious sedation: a case series. Acad Emerg Med. 1995 Jul;2(7):661-3.
2. Hohl CM, Sadatsafavi M, Nosyk B, et al. Safety and clinical effectiveness of midazolam versus propofol for procedural sedation in the emergency department: a systematic review. 2008. In: Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet]. York (UK): Centre for Reviews and Dissemination (UK); 1995-.
3. Green SM. Propofol in emergency medicine: further evidence of safety. Emerg Med Aust 2007;19:389-393.
4. Green SM. Research advances in procedural sedation and analgesia. Ann Emerg Med. 2007 Jan;49(1):31-6.
5. The Royal College of Emergency Medicine (RCEM) Best Practice Guideline, Procedural Sedation in the Emergency Department. August 2022.
6. Miner JR, Burton JH. Clinical practice advisory: Emergency department procedural sedation with propofol. Ann Emerg Med. 2007 Aug;50(2):182-7, 187.e1.
7. Royal College of Anaesthetists (RCoA): Guidelines for the Provision of Anaesthesia Services in the Non-theatre Environment 2024.
8. Mathieu N, Jones L, Harris A, et al. Is propofol a safe and effective sedative for relocating hip prostheses? Emergency Medicine Journal 2009;26:37-38.
9. Gagg J, Jones L, Shingler G, et al. Door to relocation time for dislocated hip prosthesis: multicentre comparison of emergency department procedural sedation versus theatre-based general anaesthesia. Emerg Med J. 2009 Jan;26(1):39-40.
10. Frymann SJ, Cumberbatch GL, Stearman AS. Reduction of dislocated hip prosthesis in the emergency department using conscious sedation: a prospective study. Emerg Med J. 2005 Nov;22(11):807-9.
11. Green SM, Andolfatto G, Krauss B. Ketofol for procedural sedation? Pro and con. Ann Emerg Med. 2011 May;57(5):444-8.
12. Thorpe RJ, Benger J. Pre-procedural fasting in emergency sedation. Emerg Med J. 2010 Apr;27(4):254-61.
13. Roback MG, Green SM, et al. Tracking and Reporting Outcomes Of Procedural Sedation (TROOPS): Standardized Quality Improvement and Research Tools from the International Committee for the Advancement of Procedural Sedation. Br J Anaesth. 2018 Jan;120(1):164-172. Fig.1