Prolonged Mechanical Ventilation in 540 Seriously Ill Older Adults: Effects of Increasing Age on Clinical Outcomes and Survival

Abstract

To investigate effects of older age, comorbidities, and physiological measures on outcomes of elderly adults requiring prolonged mechanical ventilation (PMV). Retrospective cohort study. Public long-term acute care hospital (LTACH) with an active program for ventilator weaning from PMV. Chronically seriously ill individuals with PMV aged 65 and older divided into six cohorts (65-69, 70-74, 75-79, 80-84, 85-89, ≥ 90) for comparative purposes (n = 540). Main outcomes were weaning criteria met, weaning success, discharge dispositions, and long-term survival. Other outcomes included weaning duration, LTACH days, discharge physical function, tracheostomy decannulation, and relapses to ventilator support. Weaning success was defined as 4 weeks or longer entirely free from mechanical ventilator support. The main finding from age cohort comparisons was that the likelihood of meeting weaning criteria (P = .001) and subsequent successful weaning (P = .002) decreased with age. Best predictors for weaning success in multivariable analysis were lower comorbidity burden (P < .001) and less-severe illness (P = .001). Other clinically important predictors were more-normal values in the respiratory physiology measures of rapid shallow breathing (P = .001) and static compliance (P = .003). Successful weaning was also associated with a 62% lower risk of death (P < .001). Although meeting weaning criteria and being successfully weaned decreased with increasing age, age was not the dominant factor in predicting outcomes. More importantly, individuals with PMV with better respiratory physiology and lower comorbidity burdens were more likely to be weaned and have longer survival, no matter their age.