Evolving differences in the presentation of severe asthma requiring intensive care unit admission.

BACKGROUND: The prevalence of asthma in the community has been increasing. Asthma mortality has not followed the same pattern. Patients who present with a severe asthma exacerbation share many characteristics with patients who die from asthma.

OBJECTIVE: We examined the differences in the presentation of severe asthma in adults admitted to a medical intensive care unit (MICU) over a 10-year interval.

METHODS: We reviewed the records of the MICU at the Columbia Presbyterian Medical Center for all admissions with severe asthma for the period from January 2000 to December 2001. The data collected included the number of admissions per month, baseline characteristics, initial arterial pH and PCO(2), length of ICU stay, and complications. These data were compared with similar data obtained over the period 1990-1991.

RESULTS: The number of MICU admissions per month for severe asthma decreased from 3.1 in 1990-1991 to 0.8 in 2000-2001. There was a trend toward a reduction in asthma severity as determined by a decrease in the initial arterial PCO(2) from 80 +/- 27 to 55 +/- 23 mm Hg and an increase in pH from 7.1 +/- 0.14 to 7.23 +/- 0.14 (0.10 > p > 0.05 for both). There was 1 death from severe hypoxemia and respiratory acidosis in the earlier series and no asthma deaths in the later series.

CONCLUSION: In our institution, there has been a decline in the number of patients with status asthmaticus requiring ICU admission over the past 10 years and a trend towards less advanced presentations with reduced levels of respiratory acidosis and decreased ICU length of stay. These changes may be related to improved medications, education, or access to care in the community.