Study objectives: Patients requiring mechanical ventilation for asthma are at a high risk of similar attacks and death in the future. Early recognition and treatment with systemic corticosteroids (SC) can influence outcome in near-fatal asthma (NFA). We studied the ability of patients to recognize the severity of asthma, implement SC therapy, and seek timely help from a health-care provider (HCP).
Design: Retrospective review of patient histories and medical records.
Setting: Medical ICU and inpatient medical ward of an inner-city university hospital.
Patients: Asthma patients requiring mechanical ventilation.
Methods: Seventy episodes of NFA requiring endotracheal intubation (intubation group [IG]) and 523 hospital admissions with acute asthma (nonintubation group [NIG]) were analyzed over a 4-year period from January 1997 to September 2000. Prior intubation(s), duration of symptoms, steroid dependence, and knowledge and use of inhaled corticosteroids and SC were noted. Indications for mechanical ventilation, ventilatory parameters using permissive hypercapnia, sedation/paralysis, duration, extubation criteria, complications, and outcome were analyzed.
Results: Twenty-nine of 70 patients (41.4%) in the IG had at least one prior episode of NFA requiring mechanical ventilation, compared to 123 of 523 patients (23.5%) in the NIG (p < 0.005). Ten of 70 patients (14.3%) in the IG were steroid dependent, compared to 40 of 523 patients (7.6%) in the NIG (p < 0.05). Forty of 70 patients (57%) in the IG compared to 308 of 523 patients (59%) in the NIG reported noncompliance with prescribed inhaled corticosteroids (not significant). All received aerosolized β-agonist therapy, but only 11 of 70 patients (15.7%) initiated SC therapy in the IG compared to 145 of 523 patients (27.7%) in the NIG (p < 0.05). Even with symptoms > 48 h, 34 of 43 patients (79%) in the IG did not receive SC. Three patients died and four patients acquired myopathy in the IG.
Conclusion: History of intubation and steroid dependence were identified as risk factors for future intubation. Our patients with asthma in both the IG and NIG were noncompliant with inhaled corticosteroids. Despite a long duration of symptoms and knowledge of SC, the majority neither implemented self-management with SC nor contacted an HCP. Early initiation of SC (symptoms < 48 h) might have averted intubation in the high-risk group. Most of our patients were extubated successfully in < 48 h. Incidence of barotrauma was very low, probably due to utilization of permissive hypercapnia.