Management of acute asthma

It’s easy to think that the rules do not apply to me as medically, the rules often don’t apply. Asthmatics are generally poor judges of their symptoms unless they receive some training on how to manage their asthma. In 1999, an articles on self-management of asthma [1] was published stating that:

Almost 75% of admissions for asthma are avoidable, and potentially preventable factors are common in deaths from asthma. At least 40% of people with asthma do not react appropriately when their symptoms worsen, and over 50% of patients admitted with acute asthma have had alarming symptoms for at least a week before admission. As many as 60% of asthmatic patients are poor at judging their dyspnoea

The same studies goes on to say that patient education helps. Patients usually are and should be educated on how to manage their condition, including how to make decisions during an asthma attack. Popular guidelines are the 4-4-4 rule (4 puffs, wait 4 minutes, 4 puffs) and in the UK, it’s generally the “one puff every minute for five minutes or until symptoms improve”. Both of these are followed with the advice that if symptoms do not improve after five minutes, call an ambulance. These are great guidelines and I’m sure they help save lives, but if I followed this guideline, I would be calling an ambulance at least twice a day. My asthma is as well-controlled as it can be, but it’s atypical and managing it is an imperfect art.

There are stages of acute asthma – moderate, severe, life-threatening and near-fatal. Moderate asthma attack is usually characterised by shortness of breath and a peak flow (PEF) of 50 – 75% of best. Signs of a severe asthma attack is:

  • peak flow 33–50% best or predicted
  • respiratory rate >25/min
  • heart rate >110/min
  • inability to complete sentences in one breath.

A life-threatening attack is denoted by any one of the following: peak flow <33% best or predicted, SpO2 <92%,PaO2 <8 kPa,normal PaCO2 (4.6–6.0 kPa), silent chest,cyanosis, feeble respiratory effort, bradycardia, dysrhythmia, hypotension, exhaustion, confusion, coma. A near-fatal attack is characterised by raised PaCO2 and/or requires mechanical ventilation with raised inflation pressures.

It’s a difficulty decision to make, when to call an ambulance. Brittle asthma is characterised by sudden severe attacks, but not every asthma attack I have is sudden or severe. I do rely on peak flow readings and respiratory rate quite a bit. I start to really pay attention when peak flow is below 30% of personal best (420 for me) and respiratory rate is >30. Rapid pulse is not a helpful indicator as sitting up causes my pulse to shoot over 110 and dysautonomia + heart condition makes tachycardia an unreliable predictor. My reasoning is usually pretty simplistic: use inhaler every minute until breathing either improves or worsen to the point where I can’t breathe at all. If it’s the first, great, attack aborted, if it’s the second, adrenalin shot time, give it a couple of minutes, then back to inhaler every minute if possible. Give it a few minutes and unless adrenaline shot significantly improves breathing, call 999.

Personally, I don’t worry until my BP starts to drop, my pulse hovers below 50 and/or my skin turns cold and clammy. I don’t worry about severe asthma, life-threatening is a word that makes me sit up and notice, but it’s near-fatal that really grabs my attention. Living with a serious medical condition like EDS and all the complications it creates makes it impossible to apply standard guidelines and panic over possibilities. Asthma attacks are serious to me when it gets to the point where terms like ‘mechanical ventilation’ is used. Ambulance trips that end in intensive care are serious, calling an ambulance isn’t.

[1] Lahdensuo A. Guided self-management of asthma–how to do it. BMJ 1999;319:759-60. (18 September.)