275 Emerg Med J: first published as 10.1136/emj.2003.005769 on 22 April 2004. Downloaded from CLINICAL TOPIC REVIEW Emerg Med J: first published as 10.1136/emj.2003.005769 on 22 April 2004. Downloaded from Ketamine for paediatric sedation/analgesia in the emergency department M C Howes ............................................................................................................................... Emerg Med J 2004;21:275–280. doi: 10.1136/emj.2003.005769 This review investigates the use of ketamine for paediatric pain or other noxious stimuli, with relative preservation of respiratory and cardiovascular sedation and analgesia in the emergency department functions despite profound amnesia and analge- ........................................................................... sia,10 30–32 described as ‘‘cataleptic.’’10 This trance- like state of sensory isolation provides a unique combination of amnesia, sedation, and analge- he injured child presents a challenge to sia.7103031 The eyes often remain open, though emergency department (ED) practitioners. nystagmus is commonly seen. Heart rate and The pain and distress can be upsetting for T blood pressure remain stable, and are often staff as well as parents. The child’s distress can stimulated, possibly through sympathomimetic be compounded by the fear of a painful actions.30 31 33 Functional residual capacity and procedure to follow, previous conditioning from tidal volume are preserved, with bronchial unexpected ‘‘jabs’’ when receiving immunisa- smooth muscle relaxation34–37 and maintenance tions, or previous visits to an ED.1 of airway patency and respiration.10 30 31 38 As doctors we strive to relieve pain and However, despite the enthusiasm of many suffering, and swear to do no harm. Forced authors and practitioners, ketamine may not be restraint, still performed in some departments in the ideal agent. Emergence reactions, sub- the country (personal communications), is no anaesthetic conditions, and airway problems do longer acceptable and may compound the hospi- occur,10 16 39–41 and it is generally recommended tal—and needle—phobia throughout life.1–3 that only physicians skilled in airway manage- Distraction techniques, play therapy, and ade- ment and resuscitation are involved in the care of quate analgesia may be sufficient to produce a sedated children. cooperative, relaxed child.45 When this fails the Is ketamine sedation the answer for the alternatives to enable a pain free treatment of the unconsolable injured child requiring a painful injury are general anaesthesia or sedation.6 procedure in the emergency department? Such a To compare these two approaches we must child could require exploration of a wound, a consider several factors; firstly, the ideal require- http://emj.bmj.com/ strange adult with instruments invading the http://emj.bmj.com/ ments of the agent to be used: rapid onset, child’s personal space, and attention to func- adequate depth of sedation and anxiolysis, tional and cosmetic outcome. Assuming distrac- maintenance of spontaneous respiration, lack of tion therapy has failed, a three part question can response to the painful stimulus, rapid recovery, be formulated thus: and minimal side effects.67 Secondly, the staff- ‘‘In [children with injuries requiring a painful ing, equipment, and facilities required. Thirdly, procedure] is [ketamine sedation/analgesia] a the preference of the parent, who acts as the [safe and acceptable technique in the A&E child’s advocate; lastly, the procedure proposed. on September 28, 2021 by guest. Protected copyright. department]?’’ on September 28, 2021 by guest. Protected copyright. The phencyclidine derivative ketamine has been described as the ideal agent for paediatric sedation in EDs,8–18 with departments in the LITERATURE SEARCH UK,19–21 USA,22 23 Australia24 25 Europe, Japan, Databases: Medline 1966 to present and Embase Mexico, the Middle East (Green SM unpublished 1980 to present via the Ovid interface. data), and Singapore26 using the technique To specify trials involving the randomised regularly. The American College of Emergency comparison of ketamine with other sedative Physicians27 and the Australasian College of agents the following strategy was used: Emergency Medicine28 both have formal guide- ‘‘ketamine.mp. AND (children or child$ or pae- lines for emergency physicians specifically for diatric or paediatric$ or pediatric or pediatric$). ketamine sedation, although the latest national mp.’’ AND ( maximally sensitive randomised guideline on paediatric sedation in the United control trial filter).43 Kingdom recommends ‘‘…the general anaesthetic A further search for additional papers was agents […ketamine…]…are only used by those performed with the following strategy: (keta- formally trained in paediatric or neonatal anaesthesia mine or ketamin$).mp. AND (children or child$ ....................... or intensive care…’’29 or paediatric or paediatric$ or pediatric or Correspondence to: Ketamine is a unique drug giving complete pediatric$).mp. AND (emergency or emergenc$ Dr M C Howes, Emergency anaesthesia and analgesia with preservation of or accident or accident$ or (accident and Department, Royal Preston vital brain stem functions. This ‘‘dissociative’’ emergency)).mp. Hospital, Sharoe Green state has been described as ‘‘a functional and No limits were applied. The results were Lane, Preston PR2 9HT, neuro-physiological dissociation between the neocortical assessed for relevant articles by searching the UK; martenhowes@ 30 doctors.org.uk and limbic systems.’’ Ketamine dissociation abstracts. The references of review articles were ....................... results in a clinical state of lack of response to also searched for any additional papers of www.emjonline.com 276 Howes relevance, and the following journals were hand searched for Emerg Med J: first published as 10.1136/emj.2003.005769 on 22 April 2004. Downloaded from recent articles not yet included in the Medline or Embase databases that may be relevant: Annals of Emergency Medicine, Academic Emergency Medicine, Emergency Medicine Journal, Emergency Medicine, American Journal of Emergency Medicine, bias Pediatric Emergency Care. ? Other sources include data from Lancaster Royal Infirmary blinded, low numbers, and communications with authors in the field of ketamine ? sedation in children in A&E (Ray McGlone, Lancaster, UK, and Steven Green, California). selected for ketamine, no blinding Good blinding. assessment of sedation by operator Initially combative children No blinding, no randomisation, powered, tolerance scale not validated Different local anaesthesia, not Comments RESULTS Randomised trials comparing ketamine with other agents When comparing agents used for sedation the primary outcome measures must be the characteristics of our mythical ‘‘ideal agent.’’67 Only three trials were identified that directly compared ketamine alone with another sedative agent. Others used combinations of sedatives, were studying ketamine in the Results but ldquo;deeper,’’ better parent and doctor satisfaction parent preference for ketamine satisfaction with ketamine, less restraint needed with ketamine Better sedation with ketamine Less restraint with ketamine, Less agitation and better parent context of general anaesthesia for surgery in an operating Lower sedation score with ketamine and better tolerance environment, or studying the pharmacology of ketamine. Others studied ketamine for critical care procedures. One study was placebo controlled. Table 1 summarises these three trials. The trial published by Acworth et al44 is included to highlight UK experience and the attempts at blinding the investigators made. The trial was confounded as ketamine was given with midazolam. It is difficult to perform a truly blinded comparison of Outcomes Physiology, sedation score, parent assessment of sedation Behaviour, restraint, parent satisfaction Behaviour, restraint, parent satisfaction sedative agents. Tolerance, time to sedation, parental acceptance, adverse events Acworth et al44 blinded the observers by bringing them into the sedation room to score the sedation level after drug administration and placing dummy intravenous cannulas on the patients. They also attempted to perform a quality control on their blinding by asking the observers to guess which sedation agent had been given; observers were right in 55%. However, these observers may introduce bias as the ketamine dissociated state can be recognised from other sedation flumazenil, IM http://emj.bmj.com/ 10 17 2 / IN midazolam 0.4 mg/kg, IN midazolam 0.5 mg/kg, IM midazolam 0.4 mg/kg IV midazolam 0.1 mg/kg IM ketamine 2.5 mg/kg Oral ketamine 10 mg/kg, + ketamine 2.5 mg/kg IV ketamine 1 mg/kg plus levels. A study blinding the data analysis from the oral midazolam 0.7 mg/kg clinicians has yet to be reported, and so additional bias remains in the published work. Varying sedation scoring systems, and definitions of ‘‘agitation’’ and ‘‘satisfaction’’ complicate the analysis. The conclusion is that ketamine appears to provide better conditions of sedation, though a somewhat different level of sedation than other agents. Definitions of sedation levels will be dealt with later in this on September 28, 2021 by guest. Protected copyright. Number of patients Treatment arms review. 59 Attempts to compare side effects of sedative agents would require statistical powering. Green et al45 calculated that 7216 subjects would be required for a study to detect a 50% relative difference in airway complications