Prediction of ICU Delirium: Validation of Current Delirium Predictive Models in Routine Clinical Practice.

OBJECTIVES: To investigate the ability of available delirium risk assessment tools to identify patients at risk of delirium in an Australian tertiary ICU. DESIGN: Prospective observational study. SETTING: An Australian tertiary ICU. PATIENTS: All patients admitted to the study ICU between May 8, 2017, and December 31, 2017, were assessed bid for delirium throughout their ICU stay using the Confusion Assessment Method for ICU. Patients were included in this study if they remained in ICU for over 24 hours and were excluded if they were delirious on ICU admission, or if they were unable to be assessed using the Confusion Assessment Method for ICU during their ICU stay. Delirium risk was calculated for each patient using the prediction of delirium in ICU patients, early prediction of delirium in ICU patients, and Lanzhou models. Data required for delirium predictor models were obtained retrospectively from patients medical records. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: There were 803 ICU admissions during the study period, of which 455 met inclusion criteria. 35.2% (n = 160) were Confusion Assessment Method for ICU positive during their ICU admission. Delirious patients had significantly higher Acute Physiology and Chronic Health Evaluation III scores (median, 72 vs 54; p < 0.001), longer ICU (median, 4.8 vs 1.8 d; p < 0.001) and hospital stay (16.0 vs 8.16 d; p < 0.001), greater requirement of invasive mechanical ventilation (70% vs 21.4%; p < 0.001), and increased ICU mortality (6.3% vs 2.4%; p = 0.037). All models included in this study displayed moderate to good discriminative ability. Area under the receiver operating curve for the prediction of delirium in ICU patients was 0.79 (95% CI, 0.75-0.83); recalibrated prediction of delirium in ICU patients was 0.79 (95% CI, 0.75-0.83); early prediction of delirium in ICU patients was 0.72 (95% CI, 0.67-0.77); and the Lanzhou model was 0.77 (95% CI, 0.72-0.81). CONCLUSIONS: The predictive models evaluated in this study demonstrated moderate to good discriminative ability to predict ICU patients' risk of developing delirium. Models calculated at 24-hours post-ICU admission appear to be more accurate but may have limited utility in practice.

Persistent Critical Illness and Long-Term Outcomes in Patients With COVID-19: A Multicenter Retrospective Cohort Study.

OBJECTIVES: A nontrivial number of patients in ICUs experience persistent critical illness (PerCI), a phenomenon in which features of the ICU course more consistently predict mortality than the initial indication for admission. We aimed to describe PerCI among patients with critical illness caused by COVID-19, and these patients' short- and long-term outcomes. DESIGN: Multicenter retrospective cohort study. SETTING: Australian and New Zealand Intensive Care Society Adult Patient Database of 114 Australian ICUs between January 1, 2020, and March 31, 2022. PATIENTS: Patients 16 years old or older with COVID-19, and a documented ICU length of stay. EXPOSURE: The presence of PerCI, defined as an ICU length of stay greater than or equal to 10 days. MEASUREMENTS: We compared the survival time up to 2 years from ICU admission using time-varying robust-variance estimated Cox proportional hazards models. We further investigated the impact of PerCI in subgroups of patients, stratifying based on whether they survived their initial hospitalization. MAIN RESULTS: We included 4961 patients in the final analysis, and 882 patients (17.8%) had PerCI. ICU mortality was 23.4% in patients with PerCI and 6.5% in those without PerCI. Patients with PerCI had lower 2-year (70.9% [95% CI, 67.9-73.9%] vs. 86.1% [95% CI, 85.0-87.1%]; p < 0.001) survival rates compared with patients without PerCI. Patients with PerCI had higher mortality (adjusted hazards ratio: 1.734; 95% CI, 1.388-2.168); this was consistent across several sensitivity analyses. When analyzed as a nonlinear predictor, the hazards of mortality were inconsistent up until 10 days, before plateauing. CONCLUSIONS: In this multicenter retrospective observational study patients with PerCI tended to have poorer short-term and long-term outcomes. However, the hazards of mortality plateaued beyond the first 10 days of ICU stay. Further studies should investigate predictors of developing PerCI, to better prognosticate long-term outcomes.