Sedation

Overview

The aim of sedation is to reduce anxiety, agitation, and pain so that patients can tolerate unpleasant medical procedures or interventions while maintaining control of their airway, breathing, and blood pressure.

Procedural sedation and analgesia are commonly used in:

• Emergency departments

• Radiology and diagnostic units

• Dentistry

• Endoscopic procedures

• Gynaecological procedures

Minimal sedation (anxiolysis)

Minimal sedation is appropriate when analgesia is not required.

Use one of the following:

Diazepam (IV)

• 0.1 mg/kg.

For a 60 kg patient:

• Administer 2 mg boluses every minute.

• Up to 10 mg may be required.

OR

Nitrous oxide (inhaled)

• 20–50% in oxygen.

Note: Nitrous oxide also provides some analgesia.

OR

Midazolam (IV)

• 0.05 mg/kg.

For a 60 kg patient:

• Administer 1 mg boluses every minute.

• Up to 3 mg may be required.

Moderate sedation and analgesia

If analgesia is required, one of the sedative agents above is usually combined with an opioid.

Ketamine has intrinsic analgesic properties and may be used alone or in combination with a benzodiazepine.

Ketamine (IV)

• 0.5 mg/kg.

• Repeat 0.5 mg/kg every 5–10 minutes as required.

OR

Morphine (IV)

• 0.1 mg/kg.

• Administer in 2 mg increments every 5 minutes as required.

OR

Fentanyl (IV)

• 0.25 micrograms/kg.

Alternative agents

Propofol (IV)

• Initial dose: 0.5 mg/kg.

• Repeat 0.25 mg/kg boluses every 5 minutes as required.

OR

Etomidate (IV)

• Initial dose: 0.1 mg/kg.

• Repeat 0.05 mg/kg every 5 minutes as required.

Note: Etomidate is more likely to cause myoclonus.

Deep sedation and analgesia

Deep sedation is usually achieved by:

• Using higher doses of medications recommended for moderate sedation, or

• Combining:

  • an opioid,

  • a benzodiazepine, and

  • either propofol or etomidate.

When multiple agents are combined, lower doses of each medication may be adequate.

Supplemental analgesia for procedural sedation

Simple analgesics may be administered before or after the procedure.

Paracetamol (PO)

• 1 g every 4–6 hours as required.

• Maximum: 4 doses within 24 hours.

Maximum dose:

• 15 mg/kg per dose

• 4 g within 24 hours

OR

Ibuprofen (PO)

• 400 mg every 8 hours with meals after the procedure.

Sedation in intensive care

General principles

• The indication for sedation should be defined individually for each patient.

• Sedation may be required for:

  • Anxiolysis

  • Analgesia

  • Control of agitation

  • Tolerance of uncomfortable procedures such as intubation and mechanical ventilation

• Sedation requirements may change rapidly and require regular reassessment.

• Adequate pain control is often more effective than sedatives in reducing agitation.

• Delirium should always be considered and managed appropriately.

Short-term sedation (less than 24 hours)

Use one of the following:

Midazolam (IV)

• 0.05–0.2 mg/kg/hour.

OR

Propofol (IV)

• 0.5 mg/kg/hour.

Note: Because of its high fat solubility, midazolam behaves as a long-acting agent after infusions lasting more than 24 hours.

Long-term sedation (72 hours or more)

Use one of the following:

Lorazepam (IV)

• 0.1 mg/kg/hour.

OR

Midazolam (IV)

• 0.2 mg/kg/hour.

Note: Lorazepam (0.1 mg/kg/hour) is as effective as midazolam (0.2 mg/kg/hour) and is similarly easy to wean, although it is more difficult to titrate.

Supplemental analgesia during intensive care sedation

Morphine (IV)

• 0.1–0.2 mg/kg/hour.

OR

Fentanyl (IV)

• 1 microgram/kg/hour.

Note: Following prolonged infusion, fentanyl also becomes long acting because of its high fat solubility.