Abstract
BACKGROUND: ICU admissions among very old patients are increasing. Invasive ventilation (IV) is common, but its benefit in patients aged ≥ 90 years is uncertain given high mortality and ethical concerns. METHODS: This retrospective cohort study analysed all consecutive ICU patients aged ≥ 90 years admitted between 2008 and 2023 at a tertiary care centre in Germany. Demographic, clinical, and outcome data were extracted from electronic health records. Multivariable logistic regression was used to identify predictors of hospital mortality, while Kaplan-Meier survival analysis and Cox proportional hazards regression were used to assess predictors of 1-year mortality. RESULTS: Of 113,950 patients, 1422 (1.25%) aged ≥ 90 years were identified (median 92 years, IQR 91-94; 66% female). IV was administered to 434 patients (31%), while 988 (69%) were not invasively ventilated. Median ICU length of stay was 1.7 days (IQR 1-4) overall. Among ventilated patients, the median duration of IV was 13 h (IQR 4-44), and 66% received IV for less than 24 h. IV was associated with higher illness severity at admission (SOFA score 9 [IQR 7-11] vs. 2 [IQR 1-4], p < 0.001), longer ICU stays (2.9 days [IQR 1.1-7.4] vs. 1.5 days [IQR 0.9-3.1], p < 0.001), as well as higher requirement of vasopressors at admission (0.112 µg/kg/min [IQR 0.056-0.278] vs. 0.072 µg/kg/min [IQR 0.038-0.133], p < 0.001) and renal replacement therapy (3.5% [n = 15] vs. 1.7% [n = 17], p = 0.042). In patients requiring IV, ICU and hospital mortality were 35.7% (n = 155) and 49.3% (n = 214) vs. 11.5% (n = 114) and 21.5% (n = 212) in non-IV patients, respectively (both p < 0.001). Independent and significant predictors of hospital mortality included prolonged IV duration (> 72 h: OR 4.01), peak lactate ≥ 4 mmol/l within 72 h (OR 6.67), as well as elevated SOFA scores (4-7: OR 1.96, ≥ 8: OR 3.46), and CCI ≥ 3 (OR 1.74) at admission. One-year mortality risks were 73.2% (95% CI 68.5-77.3%) and 53.4% (95% CI 50.0-56.6%) for IV and no-IV patients (p < 0.001), respectively. CONCLUSIONS: In this selected cohort of ICU patients aged ≥ 90 years, invasive ventilation-particularly beyond 72 h-identified a subgroup with very high ICU and hospital mortality and greater illness severity. These observational data support using invasive ventilation in nonagenarians as a trigger for early, patient-centred goals-of-care discussions, rather than as evidence that ventilation itself causes excess mortality.