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Re: Variation in the management of acute exacerbations of asthma in New South Wales.

Dear Editor

We read with interest the article by Babl et al (1) as its findings closely correlate with our own. In a recent audit we studied the management of cases of acute exacerbations of childhood asthma referred to NETS (New South Wales newborn and paediatric Emergency Transport Service). Many are referred from smaller regional paediatric units. Advice is offered by specialists from the tertiary children’s hospitals and our own staff, with retrieval offered if required. We believe this gives us good insight into the practice of physicians in both types of institution, at least with children with moderate or more severe acute asthma.

Between July 2006 and June 2007 we identified 90 cases of acute exacerbation of asthma from 31 separate institutions. Clinical advice was offered by paediatric intensive care specialists in 57 cases (63%), and paediatric emergency specialists in 47 cases (52%). A NETS specialist was involved in each of the calls. In 83 cases (92%) the child was transferred to one of the children’s hospitals in New South Wales (NSW).

Based on the NSW Clinical Practice Guideline (CPG) (2) 10 cases were graded as life-threatening, 62 as severe and 18 as moderate. Although some treatment strategies were consistent amongst physicians, several showed noteworthy variability.

Ipratropium bromide

The role of inhaled ipratropium bromide continues to be disputed (3). In our study, the treatment was used in just half of the severe or life- threatening cases, and was suggested by tertiary specialists in only a further 10 per cent.

IV salbutamol

By the time of the referral call almost two-thirds of cases (58) had received intravenous (IV) salbutamol by either bolus (28) and / or infusion (41). The dose range of bolus salbutamol was 5 – 15 mcg/kg with almost half being given 5 mcg/kg and half 15 mcg/kg. Tertiary specialists advised 15 mcg/kg in 5 further cases. Most (70%) IV salbutamol infusions were 5mcg/kg/min although the dose range was 0.1 – 10 mcg/kg/min. There was also considerable variability in the use of inhaled salbutamol whilst IV salbutamol was infused, - some specialists advised discontinuing inhaled treatment and others continuing.

Magnesium Sulphate

Magnesium sulphate was used or advised in 13 cases. 5 different dosing regimens were used, including infusions and boluses.

We believe our findings are representative of the treatment given to children with severe acute exacerbations of asthma in NSW and provide insight into treatment in both regional and tertiary centres. Similar to Babl et al we have noted variations in clinical practice in the use of some of the major therapeutic agents.

The terminology for IV salbutamol administration in particular can be misleading. “Bolus” can be misinterpreted as a “load” prior to infusion, as a “load” of 5 mcg (or even 15mcg) over 10 minutes is a less drug delivery than an infusion at 5 mcg/kg/min.

We welcome further research and clarification of these important points, not least because the confusion they can produce may result in the errors in prescribing and administration that we have seen during our practice.

S Paget 1 , C Webber 2 1 Queen Elizabeth Hospital, Woolwich UK 2 Deputy Medical Director, NETS, POB 205 Westmead NSW 2145 Correspondence to: Dr Simon Paget, Queen Elizabeth Hospital NHS Trust, Stadium Road, Woolwich SE18 4Q UK; simonpaget@gmail.com Competing Interests: None.