COCHRANE COMMENTARIES edited by Katrina Williams (Katrina.Williams@rch.org.au) written by Mike South (Mike.South@rch.org.au) and Katrina Williams (Katrina.Williams@rch.org.au) Evidence to support current use of nebulised epinephrine in croup to achieve immediate clinical improvement What is this review about? The use of epinephrine for the treatment of croup assessed by improvement in clinical score. What are the findings? Epinephrine is associated with clinically and statistically signifi- cant transient reduction of symptoms of croup 30 minutes post- treatment. Evidence does not favour racemic epinephrine or L-epinephrine, or intermittent positive pressure breathing over simple nebulization. What are the findings based on? A small number of studies (N=8) and participants (N=225) with a maximum of three trials reporting similar outcomes in similar settings allowing data synthesis. None of the studies included children with mild croup. Timing of outcome mea- sures varied between studies and co-interventions (for example, corticosteroid administration) were not explicitly described for some studies. There were too few studies included to formally assess publication bias. The majority of the studies were intermediate to low risk of bias, half of the studies reported adequately concealed patient allocation methods and all were double-blind. The majority of the studies reported their primary outcome, several studies reported a loss to follow up and few studies conducted an intention-to-treat analysis. No other systematic reviews on this topic were identified but it is likely that review of the evidence has taken place as part of evidence based clinical guideline preparation. Implications for practice • Nebulized epinephrine may be used to treat obstructive airway symptoms associated with moderate to severe croup. • The clinical effect of nebulized epinephrine is apparent at 30 minutes post-treatment. • There is no evidence to suggest that croup symptoms, on average, worsen after the treatment effect of nebulized epi- nephrine dissipates. • There is reasonable evidence that L-epinephrine is at least as effective as racemic epinephrine if this drug for some reason is not available. • The addition of intermittent positive pressure breathing did not appear to improve the clinical effect of epinephrine as compared with nebulization alone. Clinical perspective Nebulised adrenaline (epinephrine) has been used in the treat- ment of severe croup for many years. Anyone who uses this treatment regularly can tell you that it is effective in reducing the signs of airway obstruction because the improvements are immediate and usually very obvious (sometimes dramatically so). This review provides controlled-trial evidence to support the substantial evidence available from observation in everyday clinical practice (Figure 1). The uncertainties about nebulised adrenaline have not been about its utility in producing a short-term reduction in signs of airway obstruction, but rather if single or repeated doses can reduce the need for endotracheal intubation. Some children, despite the use of nebulised adrenaline, still require intubation. The topic has also changed somewhat in the last few years due to the routine use of corticosteroid therapy in croup. These drugs have been clearly shown to alter the course of the illness rather than just produce short term improvements in symptom scores. There is now the impression that a dose or two of adrenaline might avoid intubation while waiting for the corti- costeroids to become effective. This has not been tested in a trial situation, but would be the routine practise in many centres. It is clear that the racemic form of adrenaline offers no advan- tage over the L-isomer (the same form as used intravenously for other purposes). Given the ready availability of the L-isomer most centres have abandoned use of racemic adrenaline. Nebulized epinephrine for croup in children. Bjornson C, Russell KF, Vandermeer B, Durec T, Klassen TP, Johnson DW. Cochrane Library DOI: 10.1002/14651858.CD006619.pub2 http://onlinelibrary.wiley.com/o/cochrane/clsysrev/articles/CD006619/ frame.html All residents of Australia can access The Cochrane Library for free, thanks to funding provided by the Australian Government and admin- istered by The Department of Health and Ageing. doi:10.1111/j.1440-1754.2012.02436.x Journal of Paediatrics and Child Health 48 (2012) 279–280 © 2012 The Authors Journal of Paediatrics and Child Health © 2012 Paediatrics and Child Health Division (Royal Australasian College of Physicians) 279