Contra-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, Biers 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.