Intranasal Ketamine: Mum “Nose” Best at St Emlyn’s
St Emlyn’s in Virchester is a place full of talent, only a small cross-section of which is showcased here. Now and then, the opportunity to highlight the work of other Emergency Physicians arises.
Such an opportunity has come about in the last few weeks; Dr. Alison Robinson, an ED Registrar and mum to two girls, has been thinking about the opportunities for intranasal delivery of ketamine in the ED to kids needing procedural sedation. If you’re a regular reader of twitter you’d be forgiven for thinking ketamine cures all manner of ailments – it’s certainly a frequent topic of debate, and the subject of intranasal use has come up more than once.
So what does Alison think? Find out below, and remember: Mum “nose” best
Trying to balance life as a working Mother is tough, but when your two worlds collide you find knowledge of one increases the horrors of the other. Such is where I found myself, pinning my 20-month-old daughter down, whilst an eager Paeds trainee stuck needles in her. Holding her, watching her petechial rash increase across the SVC distribution as she screamed, I knew that the bloods being obtained were necessary, and the antibiotics needed – the possibility of the humbling meningococcal septicaemia not a risk any of us would be prepared to take. However, my thoughts drifted to the children that I do this, or worse, to…
What about the children getting IM injections; in my practice most commonly IM ketamine?
These kids are the hurt ones, the scared ones, the systemically well ones; 100% aware of what you are doing – and it is awful! Don’t get me wrong, I believe in ketamine sedation. For the right patient it’s brilliant, but it can be a total disaster – some children getting not one but two IM injections, then being listed for a GA once the procedure has failed.
So is there a better way? Is swapping a painful IM injection for an IV cannula better? Maybe, but in the chubby, no-veins-to-be-found age group probably not. So where does that leave us? I have heard tales of intranasal ketamine being used prehospitally, seen publications examining its use in dental sedation that excited me – could this be the answer? Can we throw away the needles?
Happily, it seems I am not the only one pondering this thought. A paper recently published in Pediatric Emergency Care examined the effectiveness of intranasal ketamine for paediatric procedural sedation in the ED. Its bottom line: IN ketamine achieved adequate sedation in only 3 put of 12 children. Not great, but I’m not sure IN ketamine should throw in the towel quite yet…
Call me an optimist (you may be the only ones who ever will), but I feel there are several reasons to not banish intranasal ketamine but to keep the painless sedation hope alive. Let’s have a look at the paper: see if you agree with me.
Click the image above to go to the PubMed abstract.
The authors conducted a pilot study looking at ASA grade I and II children between 1 and 7 years who needed suturing for simple laceration repair. Inclusion and exclusion criteria seem appropriate and consistent with the patients that I would consider ketamine for – great!
Patients were then randomised by age group (12-36 months, 36-60 months and 60-84 months), to receive either 3mg/kg, 6mg/kg or 9mg/kg IN ketamine by atomiser device (0.5ml per nostril). The groups therefore are not comparable – not so great.
All children had local anaesthetic gel applied to the wounds and a Ramsay sedation score was assigned by a blinded assessor every 15 seconds until a sedation score of 4 (“patient exhibits brisk response to light glabellar tap or loud auditory stimulus”) or more was achieved. I may be at risk of opening a can of worms regarding the depth of procedural sedation required (already much has been blogged about procedural sedation), however a child with a RSS of 3 (“patient responds to commands only”), or even 2 (patient is co-operative, orientated and tranquil), may let you stitch up their leg. A child scoring RSS 6 (“patient exhibits no response”) is likely to be over sedated in this context and I would be concerned.
There is also no control group to compare sedation scores to. I wonder how their sedation practice would compare to the study protocol, do they really only perform procedures on children achieving RSS of 4 or more? I suspect not, hence their study protocol is not “true to life”. I wonder how many of our IV/IM sedations would “fail” according to this protocol.
The children were also all cannulated and had multiple blood samples taken to measure serum ketamine and norketamine. These levels did not correlate well with clinical effects, and the process of obtaining IV access and repeated sampling may have adversely effected sedation by excess stimulation.
As so few children reached the defined criteria for adequate sedation, the study was abandoned prematurely, only recruiting 12 subjects. Entirely reasonable given that they were failing to do the procedures on these children, but I am sceptical… It would have been nice to see the individual scores, and that the investigators had performed any procedures that they felt could be undertaken appropriately.
I am a huge fan of IN diamorphine, which comes as a powder, easy to dissolve and give at very high concentrations minimising runoff into the oropharynx. It is quick, easy and it works so well, so why should nasal ED delivery stop there? Ketamine, at a maximum concentration of 100mg/ml is not so concentrated, so swallowing some may become a problem in achieving predictable sedation effects. Simple things, however – like suctioning snotty noses, warming the drug slightly to prevent vasoconstriction, dividing the dose between the nostrils to maximise the surface area to absorb it and delivering the drug by atomiser – will all improve its absorption.
So can we throw away the needles? Not yet I fear… But I for one would love to see IN ketamine given another chance to prove itself, so if (or perhaps knowing my daughter, when) I find myself waiting for her to be sutured a squirt up the nose is all that’s needed. Or if it’s not, at least I will be confident in the knowledge that that needle really is necessary…
Dr Alison Robinson
And now over to you – have you used intranasal ketamine? Did it work? Thoughts and views are very welcome!