Ketamine

Ketamine is a unique dissociative drug introduced into clinical practice in 1970. This drug has an excellent track record in procedural sedation for children in emergency medicine from 1998.18

Whilst ketamine can be given both intravenously and intramuscularly, IM injections are associated with a higher risk of vomiting and a longer recovery time. There is also a perceived safety benefit of gaining secure IV access prior to the administration of any sedative medications, lest complications occur that necessitate the administration of other drugs (such as muscle relaxant for emergency intubation). For this reason, IV ketamine is recommended over IM ketamine in most instances.

Characteristics of ketamine sedation19

  • 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
  • Airway reflexes maintained
  • Cardiovascular state blood pressure and heart rate increase slightly
  • Nystagmus is typical, usually horizontal; eyes remain open and glazed

Ketamine has a number of recognised side effects,19 including:

Mild agitation (20%). Moderate to severe agitation is less common (<2%) and may be managed with benzodiazepines. Prophylactic use of benzodiazepines is not recommended.20,21

Hypersalivation and lacrimation (<10%)22,23

Involuntary movements / ataxia (5%)

Vomiting (5-10%). Prophylactic antiemetic use may be beneficial,24 although is not recommended in RCEM guidance.

Transient rash (10%)

More significant complications of ketamine sedation are uncommon, but may include:

Noising breathing (<1%), which generally requires no action, and where action is required is often improved by airway repositioning.

Apnoea (0.3%), which generally occurs when ketamine is given rapidly, and may therefore be avoided by giving boluses over 60 seconds.

Laryngospasm (0.3%), which is more likely in children with active upper respiratory infections. It is generally transient and self-limiting. Where action is required, airway repositioning (including) Larson manoeuvre and positive airway pressure administered via a facemask are usually sufficient to break the spasm.25,26 Intubation (0.02%).