Delirium prediction in the intensive care unit: comparison of two delirium prediction models

This article by Wassenaar and others was published in the May 2018 issue of Critical Care.
Background:  Accurate prediction of delirium in the intensive care unit (ICU) may facilitate efficient use of early preventive strategies and stratification of ICU patients by delirium risk in clinical research, but the optimal delirium prediction model to use is unclear. We compared the predictive performance and user convenience of the prediction model for delirium (PRE-DELIRIC) and early prediction model for delirium (E-PRE-DELIRIC) in ICU patients and determined the value of a two-stage calculation.
Methods:  This 7-country, 11-hospital, prospective cohort study evaluated consecutive adults admitted to the ICU who could be reliably assessed for delirium using the Confusion Assessment Method-ICU or the Intensive Care Delirium Screening Checklist. The predictive performance of the models was measured using the area under the receiver operating characteristic curve. Calibration was assessed graphically. A physician questionnaire evaluated user convenience. For the two-stage calculation we used E-PRE-DELIRIC immediately after ICU admission and updated the prediction using PRE-DELIRIC after 24 h.
Results:  In total 2178 patients were included. The area under the receiver operating characteristic curve was significantly greater for PRE-DELIRIC (0.74 (95% confidence interval 0.71-0.76)) compared to E-PRE-DELIRIC (0.68 (95% confidence interval 0.66-0.71)) (z score of - 2.73 (p < 0.01)). Both models were well-calibrated. The sensitivity improved when using the two-stage calculation in low-risk patients. Compared to PRE-DELIRIC, ICU physicians (n = 68) rated the E-PRE-DELIRIC model more feasible.
Conclusions:  While both ICU delirium prediction models have moderate-to-good performance, the PRE-DELIRIC model predicts delirium better. However, ICU physicians rated the user convenience of E-PRE-DELIRIC superior to PRE-DELIRIC. In low-risk patients the delirium prediction further improves after an update with the PRE-DELIRIC model after 24h.
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Effect of nocturnal sound reduction on the incidence of delirium in intensive care unit patients: An interrupted time series analysis

Introduction:  Delirium in critically-ill patients is a common multifactorial disorder that is associated with various negative outcomes. It is assumed that sleep disturbances can result in an increased risk of delirium. This study hypothesized that implementing a protocol that reduces overall nocturnal sound levels improves quality of sleep and reduces the incidence of delirium in Intensive Care Unit (ICU) patients.

Methods:  This interrupted time series study was performed in an adult mixed medical and surgical 24-bed ICU. A pre-intervention group of 211 patients was compared with a post-intervention group of 210 patients after implementation of a nocturnal sound-reduction protocol. Primary outcome measures were incidence of delirium, measured by the Intensive Care Delirium Screening Checklist (ICDSC) and quality of sleep, measured by the Richards-Campbell Sleep Questionnaire (RCSQ). Secondary outcome measures were use of sleep-inducing medication, delirium treatment medication, and patient-perceived nocturnal noise.

Results:  A significant difference in slope in the percentage of delirium was observed between the pre- and post-intervention periods (-3.7% per time period, p=0.02). Quality of sleep was unaffected (0.3 per time period, p=0.85). The post-intervention group used significantly less sleep-inducing medication (p<0.001). Nocturnal noise rating improved after intervention (median: 65, IQR: 50-80 versus 70, IQR: 60-80, p=0.02).

Conclusions:  The incidence of delirium in ICU patients was significantly reduced after implementation of a nocturnal sound-reduction protocol. However, reported sleep quality did not improve.

This article by Van de Pol and colleagues was published in Intensive & critical care nursing; August 2017.  Library members can order the full text of this and other articles via the Rotherham NHS Foundation Trust Library and Knowledge Service website using the article requests online via this link.

Outcomes of subsyndromal delirium in ICU

A systematic review to identify publications that evaluated SSD in ICU patients | Critical Care

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Background: Subsyndromal delirium (SSD) is a frequent condition and has been commonly described as an intermediate stage between delirium and normal cognition. However, the true frequency of SSD and its impact on clinically relevant outcomes in the intensive care unit (ICU) remains unclear.

Results: The six eligible studies were evaluated. SSD was present in 950 (36%) patients. Four studies evaluated only surgical patients. Four studies used the Intensive Care Delirium Screening Checklist (ICDSC) and two used the Confusion Assessment Method (CAM) score to diagnose SSD. The meta-analysis showed an increased hospital length of stay (LOS) in SSD patients (0.31, 0.12–0.51, p = 0.002; I 2 = 34%). Hospital mortality was described in two studies but it was not significant (hazard ratio 0.97, 0.61–1.55, p = 0.90 and 5% vs 9%, p = 0.05). The use of antipsychotics in SSD patients to prevent delirium was evaluated in two studies but it did not modify ICU LOS (6.5 (4–8) vs 7 (4–9) days, p = 0.66 and 2 (2–3) vs 3 (2–3) days, p = 0.517) or mortality (9 (26.5%) vs 7 (20.6%), p = 0.55).

Conclusions: SSD occurs in one-third of the ICU patients and has limited impact on the outcomes. The current literature concerning SSD is composed of small-sample studies with methodological differences, impairing a clear conclusion about the association between SSD and progression to delirium or worse ICU clinical outcomes.

Full reference: Serafim, R.B. et al. (2017) Outcomes of subsyndromal delirium in ICU: a systematic review and meta-analysis. Critical Care. Published: 12 July 2017

Extended ICU Visitation Model for Delirium Prevention

This study aims to evaluate the effect of an extended visitation model compared with a restricted visitation model on the occurrence of delirium among ICU patients | Critical Care Medicine

Interventions: Change of visitation policy from a restricted visitation model (4.5 hr/d) to an extended visitation model (12 hr/d).

Measurements and Main Results: Two hundred eighty-six patients were enrolled (141 restricted visitation model, 145 extended visitation model). The primary outcome was the cumulative incidence of delirium, assessed bid using the confusion assessment method for the ICU. Predefined secondary outcomes included duration of delirium/coma; any ICU-acquired infection; ICU-acquired bloodstream infection, pneumonia, and urinary tract infection; all-cause ICU mortality; and length of ICU stay. The median duration of visits increased from 133 minutes (interquartile range, 97.7-162.0) in restricted visitation model to 245 minutes (interquartile range, 175.0-272.0) in extended visitation model (p < 0.001). Fourteen patients (9.6%) developed delirium in extended visitation model compared with 29 (20.5%) in restricted visitation model (adjusted relative risk, 0.50; 95% CI, 0.26-0.95). In comparison with restricted visitation model patients, extended visitation model patients had shorter length of delirium/coma (1.5 d [interquartile range, 1.0-3.0] vs 3.0 d [interquartile range, 2.5-5.0]; p = 0.03) and ICU stay (3.0 d [interquartile range, 2.0-4.0] vs 4.0 d [interquartile range, 2.0-6.0]; p = 0.04). The rate of ICU-acquired infections and all-cause ICU mortality did not differ significantly between the two study groups.

Conclusions: In this medical-surgical ICU, an extended visitation model was associated with reduced occurrence of delirium and shorter length of delirium/coma and ICU stay.

Full reference: Rosa, R.G. et al. (2017) Effectiveness and Safety of an Extended ICU Visitation Model for Delirium Prevention: A Before and After Study. Critical Care Medicine: Published online: 30th June 2017

Survey among critical care nurses and physicians about delirium management

Delirium is a serious complication in patients in intensive care units. Previous surveys on delirium management in daily practice showed low adherence to published guidelines | Nursing in Critical Care

Aim: To evaluate delirium management in nurses and physicians working in intensive care units in German-speaking countries and to identify related differences between nurses and physicians.

Conclusion: In German-speaking countries, assessment of delirium needs further improvement, leading to accurate assessment. Delirium-related structures and processes appear to be implemented widely, with only a few differences between nurses and physicians.

Full reference: Nydal, P. et al. (2017) Survey among critical care nurses and physicians about delirium management. DOI: 10.1111/nicc.12299

The Confusion Assessment Method for the ICU-7 Delirium Severity Scale

Khan, B.A. et al. (2017) Critical Care Medicine. 45(5) pp. 851–857

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Objectives: Delirium severity is independently associated with longer hospital stays, nursing home placement, and death in patients outside the ICU. Delirium severity in the ICU is not routinely measured because the available instruments are difficult to complete in critically ill patients. We designed our study to assess the reliability and validity of a new ICU delirium severity tool, the Confusion Assessment Method for the ICU-7 delirium severity scale.

Conclusions: Our results suggest that Confusion Assessment Method for the ICU-7 is a valid and reliable delirium severity measure among ICU patients. Further research comparing it to other delirium severity measures, its use in delirium efficacy trials, and real-life implementation is needed to determine its role in research and clinical practice.

Read the full abstract here

Quality of clinical practice guidelines in delirium

Bush, S.H. et al. (2017) BMJ Open. 7:e013809

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Objective: To determine the accessibility and currency of delirium guidelines, guideline summary papers and evaluation studies, and critically appraise guideline quality.

Conclusions: Delirium guidelines are best sourced by a systematic grey literature search. Delirium guideline quality varied across all six AGREE II domains, demonstrating the importance of using a formal appraisal tool prior to guideline adaptation and implementation into clinical settings. Adding more knowledge translation resources to guidelines may improve their practical application and effective monitoring. More delirium guideline evaluation studies are needed to determine their effect on clinical practice.

Read the full review here