by Green, Cameron;
Bonavia, William; Toh, Candice; Tiruvoipati, Ravindranath
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.