2007 OPEN FORUM Abstracts
OUTCOME OF PATIENTS WITH ACUTE SEVERE EXACERBATIONS OF ASTHMA REQUIRING INTENSIVE CARE IN A TERTIARY CARE HOSPITAL
H. Tan1, P. Lo1, C. Eng1
Background: Acute severe asthma is associated with significant mortality and morbidity. Management is frequently complicated by barotrauma, hyperinflation, hypotension and neuromuscular weakness with the use of neuromuscular blocking agents. We undertook a study looking at outcomes of all patients admitted to the medical intensive care unit (MICU) with an acute exacerbation of asthma.
Method: Retrospective review of case-notes of all patients admitted to MICU of a 1,600 beds tertiary and university affiliated teaching hospital with an admitting diagnosis of bronchial asthma from January 2004 to April 2007.
Result: A total of 19 patients were identified during the study period. 3 patients were excluded, as the respiratory decompensation was secondary to causes other than asthma. The mean age was 57.3 years; 10 patients were male, and 6 were female. 12 cases were admitted directly to MICU from emergency department while 4 were transferred from general ward. 12 of the 16 patients required intubation and mechanical ventilation. All were treated with systemic steroids and given albuterol and ipratropium bromide (IB). Albuterol and IB were delivered with a small volume nebuliser for patients on spontaneous respiration. Intubated patients received albuterol and IB from a metered dose inhaler via spacer connected to inspiratory limb of ventilator circuit. Mean duration of mechanical ventilation was 1.9 days with no reported complications. Patients who were intubated had lower mean pH (7.23 vs. 7.31) and higher mean PaCO2 (80.48 vs. 47.18 mm Hg) compared to patients who were not intubated. All intubated patients were ventilated initially in SIMV mode with low rate of 8-14 breaths/min and tidal volume of 6 ml/kg. When there was clinical improvement, patients were converted to pressure support ventilation and extubated following a spontaneous breathing trial. The average ICU length of stay (LOS) for all patients was 2.3 days. The average hospital LOS was 10.2 days. 2 cases had a prolonged hospital stay of more than 30 days due to complications unrelated to asthma. When these 2 cases were excluded, the average hospital LOS was 4.75 days. There was no ICU nor hospital mortality for this group of patients.
Conclusion: Severe exacerbations of asthma is associated with a significant mortality. However, with aggressive respiratory therapy, and ventilatory measures to reduce pulmonary barotrauma and hyperinflation, favorable outcomes can be achieved in many patients.