Ketamine

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You can keep staring at the 3 year old’s deep eyebrow laceration, desperate to glue it, but you know it needs to be sutured. Now what?

 

Injured or distressed children present us with difficulties in the emergency department. Children experience a more intense physical and emotional reaction to painful or threatening procedures than adults. The goals of sedation of children in the emergency department include minimizing pain, anxiety, movement which may jeopardize the procedure, and maximizing the chances of success for the procedure performed, returning the patient to his or her pre-sedated state as quickly as possible while assuring the patient’s safety. In addition to minimizing the negative psychological experience for the child, sedation will reduce fear and distress in subsequent presentations to health care facilities.

Paediatric procedural sedation has become a domain of expertise in emergency medicine. As emergency physicians, we should be aware of the pros and cons of the different options within paediatric sedation, and not only skilled in the technicalities of each but in the non-clinical aspect of ensuring both the child and the caregiver have as pleasant an experience as possible.

 

Choice of sedation:

There are no hard and fast rules on what sedation to use. One must take into account many variables, including the age (and temperament) of the child, the proposed procedure, fasting time, co-morbidities, and levels of parental anxiety. If a patient or a parent is extremely anxious, or if the procedure has the potential to be very long, complex or painful, it may be more appropriate or kinder for the child to have their procedure done in theatre under general anaesthetic. In a compliant child with a laceration away from the face needing sutures, Nitrous Oxide may be ideal.

 

Prior to any form of sedation:

  • Take time to discuss the options with the parents.
  • Remember to consider systemic pain relief. If using ketamine it is important that the patient is comfortable before the drug is administered – if they are uncomfortable or agitated during administration they are more likely to have nightmares or a scary emergence.
  • ALA (or similar) should be used around wound edges, and AnGel/LMX on potential cannulations sites.
  • Local anaesthetic should be used where appropriate as the analgesic effect will outlast the ketamine.

 

Ketamine sedation:

Ketamine has been described as the “ideal” agent for paediatric sedation, and has rapidly become the drug of choice for short, painful procedures in the ED due to its rapid onset of action, and anxiolytic, analgesic and amnesic properties. Ketamine dissociation results in a lack of response to painful or noxious stimuli, whilst preserving respiratory and cardiovascular stability.

Ketamine use has previously been restricted to anaesthetists, but emergency physicians are using it more and more frequently; ACEM and ACEP both have formal guidelines for emergency physicians especially for ketamine sedations, and most departments will have a local protocol. It should, however, only ever be used in a resuscitation area by an airway trained doctor in case of laryngospasm. It is mandatory to have a separate doctor performing the procedure itself and a nurse credentialed in ketamine sedation. Local policies may specify PLS/APLS certification or similar. This may mean delaying the procedure until daylight hours or calling in the consultant if there is an urgent clinical need.

 

Absolute contraindication: infants less than 6 months (due to increased risk of airway compromise, and recent animal studies which have found that ketamine is involved in neuronal degeneration within the developing brain)

Relative contraindications:

  • age less than 12 months
  • high risk of laryngospasm (e.g. asthma, active URTI)
  • significant cardiac disease
  • reduced loc or recent head injury
  • previous psychosis
  • prior adverse reaction to ketamine

Examples of appropriate procedures:

  • Suturing
  • Reduction of fractures/dislocations
  • Burn debridement
  • Lumbar Puncture
  • Abscess drainage

 

For the parents:

For successful sedation, it is integral to involve the parents or caregivers and keep them on side. Take the time to explain the procedure to them and gain informed consent. I often given them a leaflet to read about ketamine sedation and then come back ten minutes later to answer any questions they may have. Ensure to go over what will happen, what they will see and what the child will experience.

 

Examples:

  • Your child may seem to be awake after receiving ketamine, their eyes might flicker from side to side or they might twitch – this is normal
  • They may develop a rash
  • They may vomit
  • They may drool
  •  Sometimes as your child wakes up they may be agitated or appear to be having hallucinations or nightmares. These can normally be helped by minimising sensory input (e.g. talking softly and dimming the lights), but if required we can give a drug which will help to minimise these.
  • In very few cases, we may have to give extra Oxygen or extra drugs
  • Be reassured that your child will not remember the procedure

 

How parents can help:

Keep calm themselves, reassure the child, talk softly and smoothly and describe a pleasant scene to them as they are given the drug. Remain with the child throughout the procedure and provide positive

 

Routes of administration:

Ketamine can be used intravenously or intra-muscularly, if access is likely to be problem. Studies have concluded that IV ketamine is similar to IM ketamine in terms of efficacy and safety, with no significant difference in the rates of adverse respiratory events, however higher rates of vomiting were found in intramuscular administration.

IM has also been found to last slightly longer, and time to discharge was therefore longer (129 minutes from administration to discharge with intra-muscular ketamine, versus 80 minutes with IV).

 

Dose:

  • Dissociation can usually be achieved with:
  • 1-1.5mg/kg iv (given over 1-2 mins to avoid apnoea); top up dose of 0.5mg/kg iv can be given if required
  • 4mg/kg im, a repeat dose of 2-4mg/kg can be given after 10 minutes if sedation inadequate

Note – Several studies have shown that higher ketamine doses are required for smaller children

It is normally good practice to site a cannula when the child is dissociated if using the IM route, in case the procedure takes longer or any other drugs are required, and in order to titrate any top-up doses more accurately.

 

During the procedure:

Talk gently and tell the child to choose a dream as they drift off to sleep. You can also describe (or get the parent to describe) a pleasant scene as you are administering the drug.

Adequate sedation is usually indicated by a lack of response to verbal stimuli and nystagmus.Be patient. The effects of ketamine are usually apparent 1-2 minutes after an intravenous dose, and 5 minutes after an intramuscular dose (this can seem a long time with the orthopaedic surgeon staring at you!) Top-up doses can be given as above, but ensure you have waited sufficient time before topping up.

Atropine 0.02mcg/kg up to a maximum of 0.6mg can be used to reduce the hypersalivation caused by ketamine which can lead to larynogospasm or aspiration. Recent studies have shown no benefit to routine co-administration of atropine, though prophylactic administration may be considered in procedures in which minimising oral secretions is important, such as lip or tongue wounds. It is worth having it drawn up to be administered in the event of concerns surrounding hypersalivation during the procedure.

Midazolam has previously been used for emergence phenomena, but it should be noted that unpleasant reactions are uncommon and there is no benefit from the routine prophylactic administration of midazolam in children. There is significant variation in the literature with regards to dose, ranging from 0.02mg/kg to 0.1mg/kg. I favour a dose of 0.05mg/kg, but this can be repeated if necessary. I normally don’t draw this up, but have the dose required in my head and the vial nearby should unpleasant reactions arise.

Ondansetron 0.15mg/kg would be the drug of choice for the vomiting child; some clinicians opt to give it prophylactically although there is minimal evidence to support routine use.

 

After the procedure:

Ensure to put the lights down, talk in whispers, and leave the child to wake up

Regular observations are required post procedure until the child is fully awake

 

Prior to discharge:

Ensure the child is fully awake and give them something to eat and drink

Discharge home with parents when able to mobilise and verbalise

Ensure to give appropriate post-procedure advice

 

 

 

 

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A London raised and trained ED registrar, she has temporarily swapped breaches for beaches in beautiful Northern Sydney. Passionate about all things EM – especially trauma, critical care and paediatrics – and hugely excited by the #FOAMed movement

Author: Jess Longmore

A London raised and trained ED registrar, she has temporarily swapped breaches for beaches in beautiful Northern Sydney. Passionate about all things EM – especially trauma, critical care and paediatrics – and hugely excited by the #FOAMed movement

2 Responses to "Ketamine"

  1. Kat Evans
    Kat Evans 11 months ago .Reply

    I see oral is not included in the routes of administration. We find this particularly useful for very short procedures, good option for low resource environment.

    • Andrew Tagg
      Andrew Tagg 11 months ago .Reply

      Thanks Kat.

      I have to say I have no real experience with oral ketamine in the ED. I’ve seen data regarding its use for painful dressing changes.

      What sort of dosing regime do you use?

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