Outcomes of acute respiratory distress syndrome (ARDS) in elderly patients

Abstract

Background: Elderly patients have become an increasingly prevalent proportion of the intensive care unit population. Outcomes of patients with acute respiratory distress syndrome (ARDS) have been improving in recent years, but studies of ARDS rarely include substantial numbers of elderly patients. Historically, the mortality rate for ARDS has been 69% to 80% among elderly patients. We reviewed our experience with ARDS to determine whether outcomes were improving over time, and in particular whether outcomes were equally favorable among our elderly patients aged 65 years or older.

Methods: Patients who developed ARDS in a university surgical intensive care unit from 1993 to 2003 were identified and their data were collected prospectively. Data collected included age, gender, cause of ARDS, Acute Physiology and Chronic Health Evaluation (APACHE) III score (AIII), initial Pao2:FIO2, lung injury score (LIS), maximum positive end-expiratory pressure, multiple organ dysfunction pulmonary and nonpulmonary organ dysfunction scores (MODnp), vasopressor dependence, and development of ventilator-associated pneumonia. Outcomes of patients >65 years old with ARDS were compared with those of patients <65 years old.

Results: In the study period, 343 patients developed ARDS, 210 of whom were >65 years old. Overall, age was 65.2 +/- 0.2 years, with a mean APACHE III score of 83.4 +/- 2.0 points. Sixty-six percent were men. The initial Pao2:FIO2 for the entire group was 104.3 +/- 4.1, and was less in younger patients. Maximum positive end-expiratory pressure was 15.6 +/- 0.5 cm H2O, and mean LIS was 3.3 +/- 0.6 points; these values did not differ between cohorts. Elderly patients had a mortality of 51.9% when compared with 41.7% for younger patients (p = not significant). By logistic regression analysis, factors predicting mortality included APACHE III score (each point, odds ratio [OR], 1.022; 95% confidence interval [CI], 1.008-1.035; p < 0.01) and nonpulmonary multiple organ dysfunction score (each point, OR, 1.366; 95% CI, 1.223-1.526; p < 0.0001), but neither age (p = 0.37), LIS (p = 0.49), multiple organ dysfunction pulmonary (p = 0.90), nor year of treatment (p = 0.74) had any effect on mortality.

Conclusions: The mortality rate for elderly patients with ARDS is lower in our experience when compared with historical series, even though illness severity may be higher, and comparable to that of other patients. Careful hemodynamic monitoring and resuscitation combined with other strategies to ameliorate nonpulmonary organ dysfunction achieved good outcomes in high-risk patients and could contribute in the future to further improved outcomes of elderly patients with ARDS.