An inquest into the deaths of 10 people in Melbourne’s thunderstorm asthma event of 2016 has been told the time from onset of asthma flare-up to respiratory arrest was just 15 minutes.
Giving evidence to the Victorian coronial inquest, Professor Jo Douglass, head of the Royal Melbourne Hospital’s department of allergy and clinical immunology, also noted that the pollen-induced attacks disproportionately affected people of Asian background and only three of the ten victims had an asthma action plan.
The inquest heard that high levels of rye grass pollen circulating on the 35-degree day of 21 November 2016 triggered asthma flare-ups in people across the city, including the ten who died.
Professor Douglass told the inquest that the allergen-induced flare ups were notable for their rapid onset, within minutes.
“So this would render emergency responses very time critical,” she said.
“It also behoves, I think, clinicians, to be aware of the warning signs of severe asthma and symptoms of unstable asthma leading up to it, so that perhaps that could be extended because if one recognises asthma as unstable in the hours before one has much more time in which to do something, the fifteen minutes obviously does not leave anyone time to do much.”
Few people survived respiratory arrest outside a hospital, and even inside hospital it was not assured, she told the inquest.
“So I think survival – trying to get people to hospital in that setting is obviously a major ambition of treatment.”
Case reports on the 10 victims suggested that only two of them were using reliever medication as frequently as they could have in the minutes preceding their respiratory arrest, said Professor Douglass.
The asthma emergency paradigm recommends “four puffs by four minutes and just keep repeating at sixteen puffs and then keep doing it every fifteen minutes”.
“We certainly use that in hospital…very high dose reliever puffers which could be instituted outside. And whether that could be something that might be considered in further plans to help people in that extreme or very severe event whilst waiting for help,” she said.
Nine of the victims had either been formally diagnosed with, or were known to have, asthma, but only three had formal asthma management plans. Professor Douglass said the low rate of asthma action plans was consistent with community levels of 30%, despite the plans being shown to improve asthma control and be protective against death in epidemiological studies.
“[We’ve] been banging on for 30 years about these and just doesn’t happen despite recommendations for their use. But maybe if people in…Victoria are targeted maybe that’s some way of saying you really need to think about this again,” she said.
The use of asthma action plans had since been the focus of a working party convened by Victoria’s Department of Human Services, added Professor Douglass, noting that seasonal asthma was not well recognised or addressed in current guidelines.
She told the inquest there were not many reports of ryegrass pollen exposure or seasonal allergic rhinoconjunctivitis being a trigger for asthma “and it seems to be it’s underappreciated”.
“It’s also become clear that the thunderstorm asthma event as occurred in November 2016 is probably the tip of the iceberg, and in fact recurrent admissions with weather changes are very common. So monitoring people with seasonal allergic rhinitis and whom we believe would be at risk of this would be an appropriate way of … enabling us to identify those most at risk and enable targeting of interventions in the future,” she said.
Professor Douglass’s commentary has been taken from a transcript provided by the Coroner’s Court of Victoria.