Clinical Practice Guidelines

Ketamine use in the emergency department

  • See also: Nitrous Oxide Guideline
    Analgesia & Sedation Guideline


    Ketamine is a potent sedative, amnestic, analgesic and anaesthetic agent. It has relatively little effect on the respiratory centre at the doses used.

    The airway is to be managed by a doctor approved for this purpose by the Emergency Department.

    Characteristics of ketamine dissociative state

    • Dissociation - the patient passes into a trance like state with the eyes open but not responding
    • Catalepsy - normal or slightly increased muscle tone is maintained.
    • Analgesia - excellent analgesia is typical
    • Amnesia is usually total
    • Airway reflexes are maintained.
    • Cardiovascular state - Blood pressure and heart rate tend to increase slightly.
    • Nystagmus is typical

    Potential side effects:

    • Unpleasant emergence phenomena - more common beyond mid adolescence.
    • Hypersalivation.
    • Transient laryngospasm
    • Transient apnea or respiratory depression
    • Emesis
    • Recovery agitation
    • Random purposeless movements, muscle twitching and rash are common.

    Patient selection


    • Children aged over 12 months - there is an increased risk of airway complications in children less than 12 months and particularly less than 3 months.
    • Short painful procedures especially those requiring immobilisation. Examples of these include: lacerations - especially of the face, and fracture reduction.


    • Children under 12 months
    • Food within four hours.
    • Chest infection /URTI or lung disease.
    • History of previous airway surgery or congenital anomaly.
    • Procedures that will stimulate the posterior pharynx.
    • Cardiovascular disease including hypertension.
    • Head injury with LOC, altered conscious state or vomiting.
    • Poorly controlled seizure disorder.
    • Glaucoma or acute globe injury.
    • Psychosis, Porphyria.
    • Thyroid disease.


    Staff required:

    • Airway doctor - must be approved by the Emergency Department
    • Nurse
    • Doctor for the procedure.

    Resuscitation equipment must be readily available.


    • The procedure should be explained to the caregivers and child including an explanation of the effects of Ketamine.
    • Written informed consent must be obtained.
    • Baseline observations should include BP, PR, RR and O2 saturation.
    • Encourage the child and parents to talk (dream) about happy topics. This helps minimise unpleasant emergence phenomena.

    Adjunctive agents

    • Atropine 0.02mg/kg to a maximum of 0.6mg can be used to diminish hypersalivation.
    • Midazolam 0.02 mg/kg may be added to ameliorate emergence phenomena in children over 5 years old.

    These may all be mixed in the same syringe for intramuscular or intravenous injection.

    Local anaesthetic agents may be used but are rarely required.


    IV: (with local anaesthetic cream)

    • Especially useful for procedures longer than 15-20 minutes
    • The Ketamine dose of 1-1.5 mg/kg is given slowly over (1-2 min) as more rapid administration is associated with respiratory depression.
    • Further incremental doses of 0.5mg/kg may be given if sedation is inadequate or longer sedation is necessary.
    • Atropine and Midazolam may be given prior to or with the Ketamine.


    • Ketamine can be safely used without i.v. access.
    • 3-4 mg/kg Ketamine with atropine and Midazolam mixed in the same syringe.
    • A repeat dose of 2-4 mg/kg may be given after 10 minutes if sedation is inadequate.
    Route of Administration IM IV
    Advantages No IV necessary Ease of repeat dosing, slightly faster recovery
    Clinical onset 5 minutes 1 minute
    Effective sedation 15-30 minutes 10-20 minutes
    Time to discharge (average) 100 -140 minutes 90-120 minutes


    • Each patient should have pulse oximetry and cardiac monitoring, and a nurse in attendance until recovery is well established.
    • Close observation of the airway and chest movements is necessary.

    Post procedure


    • Nil orally until fully alert
    • Nurse in a quiet area with minimal noise and physical contact, allow dim lighting if possible, and do not stimulate prematurely.
    • When patient is able to ambulate and verbalise at a level consistent with their pretreatment functioning then they may be discharged home.

    Discharge instructions

    • Careful family observation and no independent ambulating for at least two hours.