Acute asthma and the life threatening episode.
OBJECTIVE
To present a clinical approach to the management of acute asthma and the life threatening episode of asthma.


METHODS
A review of published peer-review articles and studies reported from 1966 to 1999 and identified through a MEDLINE search on the management of acute asthma, status asthmaticus and acute fulminant asthma.


RESULTS
Asthma is a disease caused by a chronic desquamative eosinophilic bronchitis with airway hyper-responsiveness to specific and non-specific stimuli. It is characterised clinically by episodic airflow obstruction. A life threatening episode indicates the presence of one of the three clinical types; acute severe asthma (an acute episode of bronchospasm where the FEV(1) is 30% or less than the predicted value), status asthmaticus (where the episode becomes resistant to beta-adrenergic agonists and corticosteroids), or acute fulminant asthma (where the onset is rapid and severe and the patient is obtunded). Management of acute severe asthma includes oxygen, continuous nebulised salbutamol (until an adequate clinical response occurs) and intravenous hydrocortisone (200 mg/70 kg i.v. followed by 50 mg/70 kg hourly or 200 mg 4-hourly). The patient's speech, conscious state, pulse and respiratory rate, peak expiratory flow rate, oximetry and blood gases should be monitored, and if there is no improvement or the patient deteriorates, admission to an intensive care unit is required. Additional therapy includes intravenous aminophylline (2mg/kg, followed by 4 mg/kg over 30 minutes), nebulised ipratropium (500 microg 6-hourly), high dose inhaled corticosteroids, intravenous magnesium sulphate (5-10 mmol as a bolus with 40 mmol over 1-2 hours), and even inhaled helium oxygen mixtures. With further deterioration or for the management of acute fulminant asthma, intravenous adrenaline (20-200microg bolus followed by an infusion of 1-10 microg/min) is often used. Endotracheal intubation, with mechanical ventilation (using low tidal volumes and low respiratory rates) ketamine anaesthesia (1-2 mg/kg followed by 50 microg/kg/min), inhaled anaesthetic agents (e.g. diethyl ether) and even extracoporeal life support (using extracorporeal membrane oxygenation) may be required.


CONCLUSIONS
Inhaled salbutamol and intravenous corticosteroids are initially administered to manage the episode of acute severe asthma. Management of acute fulminant asthma or status asthmaticus requires admission to the intensive care unit and may require anaesthetic agents and complex life support techniques.
Hegde
R M
RM
Department of Critical Care Medicine, Flinders Medical Centre, Adelaide, South Australia.
Worthley
L I
LI