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Are nebulisers or spacers better for managing acute asthma?


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This Cochrane review was published this week and here’s my summary.

This review looks at the question:

Which is better for the delivery of salbutamol in acute asthma – spacers or nebulisers?

The full version can be read here.


Why is this review useful?

It’s useful because, in my experience, different hospitals have different practices with regards to the initial management of asthma in PED. In my previous hospital we gave 3 back-to-back salbutamol nebulisers (2.5mg or 5mg depending on the age/size). In my current hospital we give 3 x 20 minutely salbutamol inhalers.


What type of patients were included?

The studies included children being managed in ED, or in the community, wih acute asthma.

People with life-threatening asthma were excluded.


How many patients were included?

This review looked at 39 studies which included 1897 children.  The review also looked at the evidence in adults.


What were the outcomes?

Primary outcomes: admission to hospital; duration of inpatient hospital stay.

Secondary outcomes: time in ED; change in respiratory rate; blood gases; pulse rate; tremor; symptom score; lung function; use of steroids; relapse rates.


What were the findings for these outcomes in ED?

There was no significant benefit in using nebulisers rather than spacers to deliver beta agonists to prevent hospital admission. And, the time spent in ED was significantly shorter (mean 33 mins) with spacers.

Pulse rate after treatment was significantly lower in children who received treatment via a spacer and development of tremor was more common in children who received nebulised treatment.

There was no difference in lung function or oxygen saturation.


Other points to note…

The authors acknowledge the uncertainty of choosing the correct dose.  The studies generally rely on titrating the treatment to the response of the patient and repeating doses as necessary.  This is good advice for real life.

The type of spacer did not affect the outcome.

The studies compared inhalers to separate nebulisers (not continuous). In practice, many hospitals use continuous nebulisers which is thought to be more effective than separate nebuliserss as it avoids rebound bronchoconstriction.


Main Conclusion

“Metered-dose inhalers with a spacer can perform at least as well as nebulisation in delivering beta-agonists in children with acute asthma”

Salbutamol has systemic side effects – tremor and increased pulse rate were more common when using nebulisers.


About the authors

  • Tessa Davis is a Consultant in Paediatric Emergency Medicine at the Royal London Hospital and a Senior Lecturer at Queen Mary University of London.


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9 thoughts on “Are nebulisers or spacers better for managing acute asthma?”

  1. Pingback: The LITFL Review 110 - Life in the Fast Lane medical education blog

  2. Thanks Tessa

    I agree paper strongly supports the practice of using spacers rather than nebulisers.

    We haven’t used nebulisers to treat asthma at RCH Melbourne since 2001, apart from the child heading to ICU with critical asthma and even then we still try to stick to spacers most of the time. If a nebuliser s used we rapidly back off to a spacer even in these v sick kids.

    Your readers might like to look at
    Successful implementation of spacer treatment guideline for acute asthma
    Which describes our experience of switching.

    Since the switch we have seen much less salbutamol toxicity. We were seeing a lot of this when we were using high dose nebulised salbutamol.

    The RCH CPG for acute asthma is at



    1. Important point about salbutamol toxicity, thanks Mike. In PED the temptation is just to chuck as much salbutamol as we can to avoid ICU. Need to always consider the systemic side effects of salbutamol.

  3. Thanks for the post! I’d have to say I’m still a big fan of nebulisers in the very sick patient who needs O2 anyway though, which for me would be where we might see a bigger clinical difference (given it’s the extreme end of the spectrum). Given this conclusion I wonder whether I’m not doing the more unwell kid any favours, although I guess there’s not really any choice if they have a mask O2 requirement.

  4. In my experience the noisy, steamy nebs scare kids +++, maybe a good source of endogenous adrenaline 🙂

    Always use spacer as it is a great chance to teach parents good technique and empower their home management strategy

    No nebs for my ED

  5. Thanks Tessa, interesting read. I am not sure the authors have chosen the most useful primary endpoints, i think the decision to admit vs stretch in ED is often somewhat subjective and with the rise of ED short stay units what is considered worthy of “admission” may now be significantly different from the times that these studies were done. Length of hospital stay is also often heavily affected by the efficiency of the in-patient rounding/review process, especially when you are measuring short admissions such as those typical of an asthma admission. I wonder if the lower rates of tachycardia and tremor in those treated with spacers are a simply a reflection of a tendency to give less salbutamol when using this delivery mechanism. The authors included children from the age of 2 and interestingly did not show the same reductions in admission rates in adults as they did in children. There is often some debate around the diagnosis of asthma in these younger children so while these results may reflect a real benefit in the pre-school aged wheezers is that benefit real in the teenage asthmatic? looking at the tables in the paper most of the studies individually do not seem overwhelming in their statistical support for their conclusions though the trends are pretty consistent. Overall though they looked at a lot of wheezy kids and failed to show any evidence at all that spacers are inferior to nebulisers. Given the opportunity for assessment and refinement of spacer technique that getting parents and kids to use their spacers under the expert supervision of ED nurses provides, I think this paper strongly supports the practice of using spacers rather than nebulisers in the asthmatics/wheezers not requiring oxygen in the ED.

  6. So that’s for preventing admission, what about acute exacerbations ie the type that call ambulance and need ED Rx? Or have comorbidity at that time eg LRTI.

  7. Thanks 4 sharing this. Great post and fantastic site.
    At our site we do a protocol for ped patients of 0.03ml/kg salbutamol per mask when doing nebulizer. I think this equals out to 0.15mg/kg though i need to clarify our hospital formulation. I have seen some places do the 2.5mg vs 5mg dose based on age/weight.
    Interested to see what others do.



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