Ketamine Summary

Pharmacology

  • NMDA receptor antagonist
  • Dissociative sedative
  • Wide safety margin
  • Maintains airway reflexes

Timing

  • Onset: 1 minute
  • Duration: 10-20 minutes
  • Discharge: 90 minutes

Indications

  • Children >12 months
  • Painful procedures
  • Fracture reduction
  • Wound management

Key Contraindications

  • Age <12 months
  • Airway procedures
  • Active respiratory infection
  • Cardiac disease
  • Psychiatric history

Dosing

  • IV: 1.0 mg/kg over 1 min
  • Lower doses: 0.6-0.8 mg/kg
  • Supplemental: 0.5 mg/kg

Complications

  • Apnea (0.3%)
  • Laryngospasm (0.3%)
  • Emergence phenomena
  • Vomiting (5-10%)

Staff Requirements

  • Sedation doctor
  • Procedure clinician
  • Monitoring nurse
  • Resuscitation area

Ketamine Procedural Sedation

Dissociative sedation for pediatric procedures in emergency care

Pharmacology

Ketamine is a phencyclidine (PCP) derivative that acts as a dissociative sedative through antagonism of the N-methyl-D-aspartate (NMDA) receptor. It has anxiolytic, analgesic, amnesic and dissociative properties with a wide safety margin.

Characteristics of Ketamine Sedation

Clinical Effects

  • Dissociation: Trance-like state with eyes open but not responding
  • Catalepsy: Normal or slightly increased muscle tone maintained
  • Analgesia: Excellent analgesia is typical
  • Amnesia: Usually total

Physiological Effects

  • Airway reflexes maintained
  • Cardiovascular state relatively stable - BP and HR increase slightly
  • Nystagmus is typical, usually horizontal

Timings of Ketamine Sedation

Phase Time
Clinical onset 1 minute
Effective sedation 10 - 20 minutes
Time to discharge 90 minutes

Indications

Ketamine can be used for procedural sedation in children over 12 months of age who will need a painful or frightening procedure during the course of their emergency care. It can be used instead of general anaesthesia for minor and moderate procedures.

Age Considerations

  • Not recommended for children under 1 year (increased risk of airway complications)
  • Caution required for children aged 2-5 years (should only be used by clinicians with significant relevant experience)

Alternative Options to Consider First

Appropriate Procedures

Common Uses

  • Wound exploration/irrigation
  • Foreign body removal
  • Suturing
  • Fracture or joint reduction/manipulation

Additional Uses

  • Burn management
  • Incision and drainage of abscess
  • Tube thoracostomy placement

Contraindications

Absolute Contraindications

  • Age < 12 months
  • Pulmonary hypertension
  • High risk of laryngospasm
  • Unstable or abnormal airway (tracheal stenosis or surgery)
  • Active upper or lower respiratory tract infection
  • Proposed procedure within the mouth or pharynx

Relative Contraindications

  • Severe psychological problems
  • Significant cardiac disease
  • Intracranial hypertension with CSF obstruction
  • Intraocular pathology
  • Previous psychotic illness
  • Uncontrolled epilepsy

Other Contraindications

  • Hyperthyroidism or thyroid medication
  • Porphyria
  • Prior adverse reaction to ketamine
  • Altered conscious level due to acute illness or injury
  • Drug/alcohol intoxication

Side Effects

Most side effects self-resolve and require observation only.

Side Effect Incidence
Mild agitation 20%
Moderate/severe agitation 1.5%
Hypersalivation and lacrimation <10%
Involuntary movements/ataxia 5%
Vomiting 5-10%
Transient rash 10%
Airway problems <1%

Complications and Management

Apnea (0.3%)

  • Can occur after rapid IV bolusing
  • Airway repositioning or brief BVM ventilation may be required
  • Prevention: IV administration over 60 seconds

Airway Misalignment (<1%)

  • Basic airway repositioning usually sufficient
  • 'Ketamine breathing' (deep sighing) can mimic stridor
  • Correct head positioning minimizes this

Laryngospasm (0.3%)

Risk factors: Higher in children with posterior pharynx stimulation or active respiratory disease (contraindications)

Management of Laryngospasm
  1. If stridor develops: attempt airway repositioning, gentle suctioning, apply high flow oxygen
  2. If saturation appropriate: continue procedure
  3. If stridor worsens or desaturation: stop procedure, BVM oxygen, call for help
  4. If saturation <92%: start gentle BVM ventilation
  5. Apply PEEP if necessary, prepare for RSI
  6. If worsening: seek help, prepare suxamethonium, proceed to RSI

Emergence Phenomena

  • Children under 10: Uncommon (1.6%)
  • Adolescents/Adults: More common (up to 33%)
  • Prevention: Positive psychology ("have a happy dream")
  • Treatment: Midazolam 0.05-0.1mg/kg if severely distressed
  • Note: Prophylactic benzodiazepines NOT necessary

Intractable Vomiting

Treatment: IV ondansetron 0.1mg/kg (maximum 4mg) by slow IV injection

Procedure Guidelines

Pre-sedation Assessment

Fasting Considerations

Recent food intake should not be considered as a contraindication to ketamine use. Consider fasting state in relation to procedure urgency and comorbidities.

Staff Requirements

Minimum Three Staff

  • Doctor: Manages sedation and airway
  • Clinician: Performs the procedure
  • Experienced Nurse: Monitors and supports patient, family, and staff

Environment and Monitoring

  • High dependency or resuscitation area
  • Immediate access to full resuscitation facilities
  • Monitoring: Sedation level, pain, ECG, BP, respiration, SpO₂, capnography
  • Observations every 5 minutes

Oxygen Administration

Supplemental oxygen should be given prior to and during the procedure. Evidence supports safety of using 'room air' only during ketamine sedation if mask use interferes with procedure.

Administration Protocol

Step-by-Step Administration
  1. Use topical anaesthesia (EMLA®, Ametop®) for IV cannulation when possible
  2. Draw up ketamine dose and calculate resuscitation drugs
  3. Encourage happy topics to minimize emergence phenomena
  4. Parents may stay until sedation achieved and during recovery
  5. IV dose: 1.0 mg/kg over at least one minute
  6. Alternative: 0.6-0.8 mg/kg for short procedures
  7. Supplemental: 0.5 mg/kg after 5-10 minutes if needed
  8. Wait 2 minutes after administration before starting painful procedures
  9. Signs of adequate sedation: loss of verbal response, nystagmus

Recovery and Discharge

Recovery Area

  • Quiet, observed, monitored area
  • Continuous observation by trained staff
  • Monitoring until vital signs normal

Discharge Criteria

  • Conscious and responding appropriately
  • Nystagmus resolved
  • Able to walk unassisted (older children)
  • Vital signs within normal limits
  • Respiratory status not compromised
  • Pain and discomfort addressed

Post-discharge Instructions

  • Rest and quiet, supervised activity for remainder of day
  • No food or drink for two hours after discharge
  • Risk of ataxia may persist - increased fall risk
  • No driving for at least 24 hours (older children/adults)
  • Provide written advice sheet to parent/guardian

Documentation

Complete medical record and local audit documentation. Document and review all adverse events. Report clinical incidents as appropriate.