ARDS in Aged Patients: Respiratory System Mechanics and Outcome

Abstract

Background: Aging is associated with physiological changes in respiratory mechanical properties. In elderly patients an increased incidence of Acute Respiratory Distress Syndrome (ARDS) resulting in increased number of elderly patients treated in Intensive Care Units (ICUs), along with increased mortality has been reported. Aim of the present study was to identify potential age-related differences in respiratory mechanics, gas exchange and ventilator settings in patients with early ARDS. The relationship between age and ICU mortality was additionally assessed. Methods: In 58 consecutive early ARDS patients demographic and anthropometric characteristics, ventilatory settings, pulmonary physiologic measurements (arterial blood gases and static respiratory mechanics) and outcome within ICU setting were recorded. Patients were divided into three age groups, those <45 yrs old (Group A, n=16), those 45-65 yrs old (Group B, n=24) and those ≥ 65 yrs old (Group C, n=18). Results: Ventilatory settings did not differ among the three ARDS age groups studied. Arterial blood gases and static respiratory mechanics were also comparable. Similarly, alveolar to arterial oxygen gradient (A-aDO2) did not differ significantly between the three groups. The middle-aged and elderly patients compared to younger ones had significantly longer length of ICU stay (p=0.018) and higher, although not significant, ICU mortality (Group A: 25%; Group B: 41.67%; Group C: 61.1%). Conclusions: An overt impact of age on respiratory system mechanics and gas exchange in early ARDS patients was not detected in our cohort. Nevertheless, elderly patients demonstrated a trend for higher mortality, along with significantly longer hospitalization in the ICU.