(423) Clinical Characteristics and Mortality of Extreme Elderly Patients Undergoing Mechanical Ventilation

Introduction: Advanced age is a risk factor for mortality (M) in critically ill patients. Frailty and comorbidities correlate with worse outcomes and are used in decisions to restrict care. This investigation describes the clinical characteristics and M of extreme elderly (EE) patients undergoing mechanical ventilation (MV), including the potential impact of sex and preadmission functional status (FS).

Methods: This IRB approved retrospective analysis of prospectively collected data includes all patients admitted to the Stamford Hospital MICU between 2009–2023 who received MV. We defined 3 cohorts: YOUNG (Y, < 75); ELDERLY (E, 75-84); and EE (>85). M was defined as status at hospital discharge. FS1 was defined as independent, living at home; FS2, partially/fully dependent, living at home; FS3, living in outside facility. We calculated Observed:Expected M ratios (OEMR, the quotient of M and APACHE IV predicted M) to determine the independent association of sex and FS1 with M.

Results: The cohort of 3706 included 2402Y, 802E and 502EE. Their median ages were 58, 79 and 88. 63.6%, 55.5% and 50.1% were male and 82.8%, 60.7% and 42.4% were FS1, respectively. Class III or IV cardiac (C) or pulmonary (P) comorbidities were more common in E and EE than in Y, and cirrhosis was more common in Y. C and P admitting diagnoses were more common in E and EE; alcohol and drug related admissions were more common in Y. M increased with increasing age (25.6% Y, 41.4% E, 50% EE), as did OEMR (0.69 Y, 0.81 E, 0.94 EE, p< 0.0001 all comparisons). Median ICU LOS were clinically similar (3.9, 3.8, 3.2 days, respectively). Males had lower OEMR than females in Y (0.67 vs 0.72, p< 0.0001) but higher OEMR in E (0.84 vs 0.78, p=0.01) and EE (0.96 vs 0.92, p=0.06). FS1 had lower OEMR than non-FS1 in all 3 groups (Y: 0.64 vs 0.86, p< 0.0001; E: 0.79 vs 0.85, p=0.04; EE: 0.85 vs 1.00, p< 0.001).

Conclusions: Despite EE undergoing MV having significantly higher M and predicted M than E and Y, those EE w better functional status had improved M compared to EE with worse FS. Despite the increased ICU M that comes with increased age and comorbidities, better FS was independently associated with lower M in all 3 groups. The divergent associations of sex with M comparing Y to E and EE merit further investigation.