Systemic inflammation and delirium during critical illness

PURPOSE

The purpose of this study was to determine associations between markers of inflammation and endogenous anticoagulant activity with delirium and coma during critical illness.

METHODS

In this prospective cohort study, we enrolled adults with respiratory failure and/or shock treated in medical or surgical intensive care units (ICUs) at 5 centers. Twice per day in the ICU, and daily thereafter, we assessed mental status using the Richmond Agitation Sedation Scale (RASS) and the Confusion Assessment Method-Intensive Care Unit (CAM-ICU). We collected blood samples on study days 1, 3, and 5, measuring levels of C-reactive protein (CRP), interferon gamma (IFN-γ), interleukin (IL)-1 beta (IL-1β), IL-6, IL-8, IL-10, IL-12, matrix metalloproteinase-9 (MMP-9), tumor necrosis factor-alpha (TNF-α), tumor necrosis factor receptor 1 (TNFR1), and protein C using validated protocols. We used multinomial logistic regression to analyze associations between biomarkers and the odds of delirium or coma versus normal mental status the following day, adjusting for age, sepsis, Sequential Organ Failure Assessment (SOFA), study day, corticosteroids, and sedatives.

RESULTS

Among 991 participants with a median age (interquartile range, IQR) of 62 [53-72] years and enrollment SOFA of 9 [7-11], higher concentrations of IL-6 (odds ratio [OR] [95% CI]: 1.8 [1.4-2.3]), IL-8 (1.3 [1.1-1.5]), IL-10 (1.5 [1.2-1.8]), TNF-α (1.2 [1.0-1.4]), and TNFR1 (1.3 [1.1-1.6]) and lower concentrations of protein C (0.7 [0.6-0.8])) were associated with delirium the following day. Higher concentrations of CRP (1.4 [1.1-1.7]), IFN-γ (1.3 [1.1-1.5]), IL-6 (2.3 [1.8-3.0]), IL-8 (1.8 [1.4-2.3]), and IL-10 (1.5 [1.2-2.0]) and lower concentrations of protein C (0.6 [0.5-0.8]) were associated with coma the following day. IL-1β, IL-12, and MMP-9 were not associated with mental status.

CONCLUSION

Markers of inflammation and possibly endogenous anticoagulant activity are associated with delirium and coma during critical illness.

Long-term outcomes after treatment of delirium during critical illness with antipsychotics (MIND-USA): a randomised, placebo-controlled, phase 3 trial

BACKGROUND

Delirium is common during critical illness and is associated with long-term cognitive impairment and disability. Antipsychotics are frequently used to treat delirium, but their effects on long-term outcomes are unknown. We aimed to investigate the effects of antipsychotic treatment of delirious, critically ill patients on long-term cognitive, functional, psychological, and quality-of-life outcomes.

METHODS

This prespecified, long-term follow-up to the randomised, double-blind, placebo-controlled phase 3 MIND-USA Study was conducted in 16 hospitals throughout the USA. Adults (aged ≥18 years) who had been admitted to an intensive care unit with respiratory failure or septic or cardiogenic shock were eligible for inclusion in the study if they had delirium. Participants were randomly assigned-using a computer-generated, permuted-block randomisation scheme with stratification by trial site and age-in a 1:1:1 ratio to receive intravenous placebo, haloperidol, or ziprasidone for up to 14 days. Investigators and participants were masked to treatment group assignment. 3 months and 12 months after randomisation, we assessed survivors' cognitive, functional, psychological, quality-of-life, and employment outcomes using validated telephone-administered tests and questionnaires. This trial was registered with ClinicalTrials.gov, NCT01211522, and is complete.

FINDINGS

Between Dec 7, 2011, and Aug 12, 2017, we screened 20 914 individuals, of whom 566 were eligible and consented or had consent provided to participate. Of these 566 patients, 184 were assigned to the placebo group, 192 to the haloperidol group, and 190 to the ziprasidone group. 1-year survival and follow-up rates were similar between groups. Cognitive impairment was common in all three treatment groups, with a third of survivors impaired at both 3-month and 12-month follow-up in all groups. More than half of the surveyed survivors in each group had cognitive or physical limitations (or both) that precluded employment at both 3-month and 12-month follow-up. At both 3 months and 12 months, neither haloperidol (adjusted odds ratio 1·22 [95% CI 0·73-2.04] at 3 months and 1·12 [0·60-2·11] at 12 months) nor ziprasidone (1·07 [0·59-1·96] at 3 months and 0·94 [0·62-1·44] at 12 months) significantly altered cognitive outcomes, as measured by the Telephone Interview for Cognitive Status T score, compared with placebo. We also found no evidence that functional, psychological, quality-of-life, or employment outcomes improved with haloperidol or ziprasidone compared with placebo.

INTERPRETATION

In delirious, critically ill patients, neither haloperidol nor ziprasidone had a significant effect on cognitive, functional, psychological, or quality-of-life outcomes among survivors. Our findings, along with insufficient evidence of short-term benefit and frequent inappropriate continuation of antipsychotics at hospital discharge, indicate that antipsychotics should not be used routinely to treat delirium in critically ill adults.

FUNDING

National Institutes of Health and the US Department of Veterans Affairs.

External validation of a predictive model for reintubation after cardiac surgery: A retrospective, observational study

STUDY OBJECTIVE

Explore validation of a model to predict patients' risk of failing extubation, to help providers make informed, data-driven decisions regarding the optimal timing of extubation.

DESIGN

We performed temporal, geographic, and domain validations of a model for the risk of reintubation after cardiac surgery by assessing its performance on data sets from three academic medical centers, with temporal validation using data from the institution where the model was developed.

SETTING

Three academic medical centers in the United States.

PATIENTS

Adult patients arriving in the cardiac intensive care unit with an endotracheal tube in place after cardiac surgery.

INTERVENTIONS

Receiver operating characteristic (ROC) curves and concordance statistics were used as measures of discriminative ability, and calibration curves and Brier scores were used to assess the model's predictive ability.

MEASUREMENTS

Temporal validation was performed in 1642 patients with a reintubation rate of 4.8%, with the model demonstrating strong discrimination (optimism-corrected c-statistic 0.77) and low predictive error (Brier score 0.044) but poor model precision and recall (Optimal F1 score 0.29). Combined domain and geographic validation were performed in 2041 patients with a reintubation rate of 1.5%. The model displayed solid discriminative ability (optimism-corrected c-statistic = 0.73) and low predictive error (Brier score = 0.0149) but low precision and recall (Optimal F1 score = 0.13). Geographic validation was performed in 2489 patients with a reintubation rate of 1.6%, with the model displaying good discrimination (optimism-corrected c-statistic = 0.71) and predictive error (Brier score = 0.0152) but poor precision and recall (Optimal F1 score = 0.13).

MAIN RESULTS

The reintubation model displayed strong discriminative ability and low predictive error within each validation cohort.

CONCLUSIONS

Future work is needed to explore how to optimize models before local implementation.

Recurrent delirium episodes within the intensive care unit: Incidence and associated factors

PURPOSE

Describe the incidence and factors associated with recurrent delirium in the intensive care unit (ICU).

MATERIALS AND METHODS

Retrospective study of ICU patients diagnosed with delirium. Delirium clearance defined as 48 h of negative delirium assessments following initial episode and recurrent delirium as any positive delirium assessment following clearance. Multivariable logistic regression model assessed independent association of patient and hospital factors on development of recurrent delirium, adjusting for pre-defined covariates.

RESULTS

Among 8591 ICU admissions identified with delirium, 1067 (12.4%) had recurrent symptoms. Factors associated with increased odds of recurrent delirium were age (nonlinear; p = 0.02), shock (OR 1.45, 95% CI [1.20, 1.75]), admission to medical (OR 3.25, 95% CI [2.42, 4.37]), surgical (OR 3.00, 95% CI [2.21, 4.06]), or trauma (OR 2.17, 95% CI [1.58, 3.00]) ICU vs. cardiovascular ICU, increased duration of mechanical ventilation (OR 2.43, 95% CI [2.22, 2.65]), propofol use (OR 1.35, 95% CI [1.02, 1.80]), and antipsychotic medications (haloperidol OR 1.53, 95% CI [1.26, 1.86]; quetiapine OR 2.45, 95% CI [1.98, 3.02]; and olanzapine OR 1.54, 95% CI [1.25, 1.88]).

CONCLUSIONS

Over 10% of delirious ICU patients had recurrent symptoms. Factors associated with recurrence included age, duration of mechanical ventilation and medication exposure.

CLINICAL TRIAL NUMBER

Not applicable.

Data-derived subtypes of delirium during critical illness

BACKGROUND

To understand delirium heterogeneity, prior work relied on psychomotor symptoms or risk factors to identify subtypes. Data-driven approaches have used machine learning to identify biologically plausible, treatment-responsive subtypes of other acute illnesses but have not been used to examine delirium.

METHODS

We conducted a secondary analysis of a large, multicenter prospective cohort study involving adults in medical or surgical ICUs with respiratory failure or shock who experienced delirium per the Confusion Assessment Method for the ICU. We used data collected before delirium diagnosis in an unsupervised latent class model to identify delirium subtypes and then compared demographics, clinical characteristics, and outcomes between subtypes in the final model.

FINDINGS

The 731 patients who developed delirium during critical illness had a median age of 63 [IQR, 54-72] years, a median Sequential Organ Failure Assessment score of 8.0 [6.0-11.0] and 613 [83.4%] were mechanically ventilated at delirium identification. A four-class model best fit the data with 50% of patients in subtype (ST) 1, 18% in subtype 2, 17% in subtype 3, and 14% in subtype 4. Subtype 2-which had more shock and kidney impairment-had the highest mortality (33% [ST2] vs. 17% [ST1], 25% [ST3], and 17% [ST4], p = 0.003). Subtype 4-which received more benzodiazepines and opioids-had the longest duration of delirium (6 days [ST4] vs. 3 [ST1], 4 [ST2], and 3 days [ST3], p < 0.001) and coma (4 days [ST4] vs. 2 [ST1], 1 [ST2], and 2 days [ST3], p < 0.001). Each of the four data-derived delirium subtypes was observed within previously identified psychomotor and risk factor-based delirium subtypes. Clinically significant cognitive impairment affected all subtypes at follow-up, but its severity did not differ by subtype (3-month, p = 0.26; 12-month, p = 0.80).

INTERPRETATION

The four data-derived delirium subtypes identified in this study should now be validated in independent cohorts, examined for differential treatment effects in trials, and inform mechanistic work evaluating treatment targets.

FUNDING

National Institutes of Health (T32HL007820, R01AG027472).

Antipsychotics and the QTc Interval During Delirium in the Intensive Care Unit: A Secondary Analysis of a Randomized Clinical Trial

Importance

Antipsychotic medications, often prescribed for delirium in intensive care units (ICUs), may contribute to QTc interval prolongation.

Objective

To determine whether antipsychotics increase the QTc interval in patients with delirium in the ICU.

Design, Setting, and Participants

An a priori analysis of a randomized clinical trial in medical/surgical ICUs within 16 centers across the US was conducted. Participants included adults with delirium in the ICU with baseline QTc interval less than 550 ms. The study was conducted from December 2011 to August 2017. Data analysis was performed from April 25 to August 18, 2021.

Interventions

Patients were randomized 1:1:1 to intravenous haloperidol, ziprasidone, or saline placebo administered twice daily until resolution of delirium, ICU discharge, or 14 days.

Main Outcomes and Measures

Twelve-lead electrocardiograms were used to measure baseline QTc before study drug initiation and telemetry was used to measure QTc before each subsequent dose of study drug. Unadjusted day-to-day changes in QTc were calculated and multivariable proportional odds regression was used to estimate the effects of antipsychotics vs placebo on next-day maximum QTc interval, adjusting for prespecified baseline covariates and potential interactions with sex. Safety end points, including the occurrence of torsade de pointes, were evaluated. All analyses were conducted based on the intention to treat principle.

Results

A total of 566 patients were randomized to haloperidol (n = 192), ziprasidone (n = 190), or placebo (n = 184). Median age was 60.1 (IQR, 51.4-68.7) years; 323 were men (57%). Baseline median QTc intervals across the groups were similar: haloperidol, 458.0 (IQR, 432.0-479.0) ms; ziprasidone, 451.0 (IQR, 424.0-472.0) ms; and placebo, 452.0 (IQR, 432.0-472.0) ms. From day 1 to day 2, median QTc changed minimally: haloperidol, -1.0 (IQR, -28.0 to 15.0) ms; ziprasidone, 0 (IQR, -23.0 to 20.0) ms; and placebo, -3.5 (IQR, -24.8 to 17.0) ms. Compared with placebo, neither haloperidol (odds ratio [OR], 0.95; 95% CI, 0.66-1.37; P = .78) nor ziprasidone (OR, 1.09; 95% CI, 0.75-1.57; P = .78) was associated with next-day QTc intervals. Effects were not significantly modified by sex (P = .41 for interaction). There were 2 occurrences of nonfatal torsade de pointes, both in the haloperidol group. Neither was associated with study drug administration.

Conclusions and Relevance

The findings of this trial suggest that daily QTc interval monitoring during antipsychotic use may have limited value in patients in the ICU with normal baseline QTc and few risk factors for QTc prolongation.

Trial Registration

ClinicalTrials.gov Identifier: NCT01211522.

In-hospital catatonia, delirium, and coma and mortality: Results from the delirium and catatonia prospective cohort investigation

BACKGROUND

Catatonia, a form of acute brain dysfunction typically linked with severe affective and psychotic disorders, occurs in critical illness with delirium and coma. Delirium and coma are associated with mortality, though catatonia's relationship with mortality is unclear. We aim to describe whether catatonia, delirium, and coma are associated with mortality.

METHODS

We enrolled a convenience cohort of critically ill adults (N = 378) at an academic medical center. We assessed catatonia, delirium, and coma using the Bush-Francis Catatonia Rating Scale, the Confusion Assessment Method for the Intensive Care Unit and the Richmond Agitation-Sedation Scale, respectively. We tested the associations between previous day brain dysfunction state occurrence with in-hospital and one-year mortality using multivariable time-dependent risk models. Additionally, we tested the association between brain dysfunction duration and one-year mortality.

RESULTS

Catatonia was not associated with death on the day after diagnosis during hospitalization, and neither previous catatonia occurrence nor duration was associated with one-year mortality. Delirium was not associated with death on any day following diagnosis during hospitalization, and neither previous delirium occurrence nor duration was associated with one-year mortality. The occurrence of coma was associated with death on any day after diagnosis during hospitalization (HR 2.30,CI 1.19-4.44,p = 0.014), as well as through one year following hospital discharge (HR 1.68,CI 1.09-2.59,p = 0.02).

CONCLUSIONS

Coma, but neither catatonia nor delirium, was associated with future day in-hospital and one-year mortality. More research is needed to understand catatonia's clinical impact. Delirium results differ from existing literature likely due to cohort demographics and size. Coma results highlight the prognostic significance of suppressed arousal while critically ill.

Advancing specificity in delirium: The delirium subtyping initiative

BACKGROUND

Delirium, a common syndrome with heterogeneous etiologies and clinical presentations, is associated with poor long-term outcomes. Recording and analyzing all delirium equally could be hindering the field's understanding of pathophysiology and identification of targeted treatments. Current delirium subtyping methods reflect clinically evident features but likely do not account for underlying biology.

METHODS

The Delirium Subtyping Initiative (DSI) held three sessions with an international panel of 25 experts.

RESULTS

Meeting participants suggest further characterization of delirium features to complement the existing Diagnostic and Statistical Manual of Mental Disorders Fifth Edition Text Revision diagnostic criteria. These should span the range of delirium-spectrum syndromes and be measured consistently across studies. Clinical features should be recorded in conjunction with biospecimen collection, where feasible, in a standardized way, to determine temporal associations of biology coincident with clinical fluctuations.

DISCUSSION

The DSI made recommendations spanning the breadth of delirium research including clinical features, study planning, data collection, and data analysis for characterization of candidate delirium subtypes.

HIGHLIGHTS

Delirium features must be clearly defined, standardized, and operationalized. Large datasets incorporating both clinical and biomarker variables should be analyzed together. Delirium screening should incorporate communication and reasoning.

Trends in use of antipsychotics and psychoactive drugs in older patients after major surgery

BACKGROUND

Professional society guidelines recommend limiting the use of antipsychotics in older patients with postoperative delirium. How these recommendations affected the use of antipsychotics and other psychoactive drugs in the postoperative period has not been studied.

METHODS

This retrospective cohort study included patients 65 years or older without psychiatric diagnoses who underwent major surgery in community hospitals (CHs) and academic medical centers (AMCs) in the United States. The outcome was the rate of hospital days exposed to antipsychotics, antidepressants, antiepileptics, benzodiazepines, hypnotics, and selective alpha-2 receptor agonist dexmedetomidine in the postoperative period by hospital type.

RESULTS

The study included 4,098,431 surgical admissions from CHs (mean age 75.0 [standard deviation, 7.1] years; 50.8% female) during 2008-2018 and 2,310,529 surgical admissions from AMCs (75.0 [7.4] years; 49.4% female) during 2009-2018. In the intensive care unit (ICU) setting, the number of exposed days per 1000 hospital-days declined for haloperidol (CHs: 33-21 days [p < 0.01]; AMCs: 24-15 days [p < 0.01]) and benzodiazepines (CHs: 261-136 days [p < 0.01]; AMCs: 150-77 days [p < 0.01]). The use of atypical antipsychotics, antidepressants, antiepileptics, and dexmedetomidine increased, while hypnotic use varied by the hospital type. In the non-ICU setting, the rate declined for haloperidol in CHs but not in AMCs (CHs: 10-6 days [p < 0.01]; AMCs: 4-3 days [p = 0.52]) and for benzodiazepines in both settings (CHs: 126-56 days [p < 0.01]; AMCs: 30-27 days [p < 0.01]). The use of antiepileptics and antidepressants increased, while the use of atypical antipsychotics and hypnotics varied by the hospital type.

CONCLUSIONS

The use of haloperidol and benzodiazepines in the postoperative period declined at both CHs and AMCs. These trends coincided with the increasing use of other psychoactive drugs.

Comparative Safety Analysis of Oral Antipsychotics for In-Hospital Adverse Clinical Events in Older Adults After Major Surgery : A Nationwide Cohort Study

BACKGROUND

Antipsychotics are commonly used to manage postoperative delirium. Recent studies reported that haloperidol use has declined, and atypical antipsychotic use has increased over time.

OBJECTIVE

To compare the risk for in-hospital adverse events associated with oral haloperidol, olanzapine, quetiapine, and risperidone in older patients after major surgery.

DESIGN

Retrospective cohort study.

SETTING

U.S. hospitals in the Premier Healthcare Database.

PATIENTS

17 115 patients aged 65 years and older without psychiatric disorders who were prescribed an oral antipsychotic drug after major surgery from 2009 to 2018.

INTERVENTIONS

Haloperidol (≤4 mg on the day of initiation), olanzapine (≤10 mg), quetiapine (≤150 mg), and risperidone (≤4 mg).

MEASUREMENTS

The risk ratios (RRs) for in-hospital death, cardiac arrhythmia events, pneumonia, and stroke or transient ischemic attack (TIA) were estimated after propensity score overlap weighting.

RESULTS

The weighted population had a mean age of 79.6 years, was 60.5% female, and had in-hospital death of 3.1%. Among the 4 antipsychotics, quetiapine was the most prescribed (53.0% of total exposure). There was no statistically significant difference in the risk for in-hospital death among patients treated with haloperidol (3.7%, reference group), olanzapine (2.8%; RR, 0.74 [95% CI, 0.42 to 1.27]), quetiapine (2.6%; RR, 0.70 [CI, 0.47 to 1.04]), and risperidone (3.3%; RR, 0.90 [CI, 0.53 to 1.41]). The risk for nonfatal clinical events ranged from 2.0% to 2.6% for a cardiac arrhythmia event, 4.2% to 4.6% for pneumonia, and 0.6% to 1.2% for stroke or TIA, with no statistically significant differences by treatment group.

LIMITATION

Residual confounding by delirium severity; lack of untreated group; restriction to oral low-to-moderate dose treatment.

CONCLUSION

These results suggest that atypical antipsychotics and haloperidol have similar rates of in-hospital adverse clinical events in older patients with postoperative delirium who receive an oral low-to-moderate dose antipsychotic drug.

PRIMARY FUNDING SOURCE

National Institute on Aging.

Effect of propranolol and clonidine after severe traumatic brain injury: a pilot randomized clinical trial

OBJECTIVE

To evaluate the safety, feasibility, and efficacy of combined adrenergic blockade with propranolol and clonidine in patients with severe traumatic brain injury (TBI).

BACKGROUND

Administration of adrenergic blockade after severe TBI is common. To date, no prospective trial has rigorously evaluated this common therapy for benefit.

METHODS

This phase II, single-center, double-blinded, pilot randomized placebo-controlled trial included patients aged 16-64 years with severe TBI (intracranial hemorrhage and Glasgow Coma Scale score ≤ 8) within 24 h of ICU admission. Patients received propranolol and clonidine or double placebo for 7 days. The primary outcome was ventilator-free days (VFDs) at 28 days. Secondary outcomes included catecholamine levels, hospital length of stay, mortality, and long-term functional status. A planned futility assessment was performed mid-study.

RESULTS

Dose compliance was 99%, blinding was intact, and no open-label agents were used. No treatment patient experienced dysrhythmia, myocardial infarction, or cardiac arrest. The study was stopped for futility after enrolling 47 patients (26 placebo, 21 treatment), per a priori stopping rules. There was no significant difference in VFDs between treatment and control groups [0.3 days, 95% CI (- 5.4, 5.8), p = 1.0]. Other than improvement of features related to sympathetic hyperactivity (mean difference in Clinical Features Scale (CFS) 1.7 points, CI (0.4, 2.9), p = 0.012), there were no between-group differences in the secondary outcomes.

CONCLUSION

Despite the safety and feasibility of adrenergic blockade with propranolol and clonidine after severe TBI, the intervention did not alter the VFD outcome. Given the widespread use of these agents in TBI care, a multi-center investigation is warranted to determine whether adrenergic blockade is of therapeutic benefit in patients with severe TBI. Trial Registration Number NCT01322048.

The genome-wide DNA methylation profiles among neurosurgery patients with and without post-operative delirium

AIMS

There is no previous study demonstrating the differences of genome-wide DNA methylation (DNAm) profiles between patients with and without postoperative delirium (POD). We aimed to discover epigenetic (DNAm) markers that are associated with POD in blood obtained from patients before and after neurosurgery.

METHODS

Pre- and post-surgical blood DNA samples from 37 patients, including 10 POD cases, were analyzed using the Illumina EPIC array genome-wide platform. We examined DNAm differences in blood from patients with and without POD. Enrichment analysis with Gene Ontology and Kyoto Encyclopedia of Genes and Genomes terms were also conducted.

RESULTS

When POD cases were tested for DNAm change before and after surgery, enrichment analyses showed many relevant signals with statistical significance in immune response related-pathways and inflammatory cytokine related-pathways such as "cellular response to cytokine stimulus", "regulation of immune system process", "regulation of cell activation", and "regulation of cytokine production". Furthermore, after excluding the potential effect of common factors related to surgery and anesthesia between POD cases and non-POD controls, the enrichment analyses showed significant signals such as "immune response" and "T cell activation", which are same pathways previously identified from an independent non-surgical inpatient cohort.

CONCLUSIONS

Our first genome-wide DNAm investigation of POD showed promising signals related to immune response, inflammatory response and other relevant signals considered to be associated with delirium pathophysiology. Our data supports the hypothesis that epigenetics play an important role in the pathophysiological mechanism of delirium and suggest the potential usefulness of an epigenetics-based biomarker of POD.

Protocol for a randomised controlled trial: reducing reintubation among high-risk cardiac surgery patients with high-flow nasal cannula (I-CAN)

INTRODUCTION

Heated, humidified, high-flow nasal cannula oxygen therapy has been used as a therapy for hypoxic respiratory failure in numerous clinical settings. To date, limited data exist to guide appropriate use following cardiac surgery, particularly among patients at risk for experiencing reintubation. We hypothesised that postextubation treatment with high-flow nasal cannula would decrease the all-cause reintubation rate within the 48 hours following initial extubation, compared with usual care.

METHODS AND ANALYSIS

Adult patients undergoing cardiac surgery (open surgery on the heart or thoracic aorta) will be automatically enrolled, randomised and allocated to one of two treatment arms in a pragmatic randomised controlled trial at the time of initial extubation. The two treatment arms are administration of heated, humidified, high-flow nasal cannula oxygen postextubation and usual care (treatment at the discretion of the treating provider). The primary outcome will be all-cause reintubation within 48 hours of initial extubation. Secondary outcomes include all-cause 30-day mortality, hospital length of stay, intensive care unit length of stay and ventilator-free days. Interaction analyses will be conducted to assess the differential impact of the intervention within strata of predicted risk of reintubation, calculated according to our previously published and validated prognostic model.

ETHICS AND DISSEMINATION

Vanderbilt University Medical Center IRB approval, 15 March 2021 with waiver of written informed consent. Plan for publication of study protocol prior to study completion, as well as publication of results.

TRIAL REGISTRATION NUMBER

clinicaltrials.gov, NCT04782817 submitted 25 February 2021.

DATE OF PROTOCOL

29 August 2022. Version 2.0.

In-Hospital Depressed Level of Consciousness and Long-Term Functional Outcomes in ICU Survivors

OBJECTIVES

Among critically ill patients, acutely depressed level of consciousness is associated with mortality, but its relationship to long-term outcomes such as disability and physical function is unknown. We investigated the relationship of level of consciousness during hospitalization with long-term disability and physical function in ICU survivors.

DESIGN

Multi-center observational cohort study.

SETTING

Medical or surgical ICUs at five U.S. centers.

PATIENTS

Adult survivors of respiratory failure or shock.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Depressed level of consciousness during hospitalization was defined using the Richmond Agitation Sedation Scale (RASS) score (including all negative scores) by calculating the area under the curve using linear interpolation. Sedative-associated level of consciousness was similarly defined for all hospital days that sedation was received. We measured disability in basic activities of daily living (BADLs), instrumental activities of daily living (IADLs), discharge destination, and self-reported physical function. In separate models, we evaluated associations between these measures of level of consciousness and outcomes using multivariable regression, adjusted for age, sex, race, body mass index, education level, comorbidities, baseline frailty, baseline IADLs and BADLs, hospital type (civilian vs veteran), modified mean daily Sequential Organ Failure Assessment score, duration of severe sepsis, duration of mechanical ventilation, and hospital length of stay. Of the 1,040 patients enrolled in the ICU, 781 survived to hospital discharge. We assessed outcomes in 624 patients at 3 months and 527 patients at 12 months. After adjusting for covariates, there was no association between depressed level of consciousness (total or sedation-associated) with BADLs or IADLs at either 3- or 12-month follow-up. There was also no association with self-reported physical function at 3 or 12 months or with discharge destination.

CONCLUSIONS

Depressed level of consciousness, as defined by the RASS, was not associated with disability or self-reported physical function. Future studies should investigate additional modifiable in-hospital risk factors for disability and poor physical function following critical illness.

Quantitative EEG During Critical Illness Correlates with Patterns of Long-Term Cognitive Impairment

OBJECTIVE

Many intensive care unit (ICU) survivors suffer disabling long-term cognitive impairment (LTCI) after critical illness. We compared EEG characteristics during critical illness with patients' 1-year neuropsychological outcomes.

METHODS

We performed a post hoc analysis of patients in the BRAIN-ICU study who had undergone EEG for clinical purposes during admission (n = 10). All survivors underwent formal cognitive assessments at 12-month follow-up. We evaluated EEGs by conventional visual inspection and computed 10 quantitative features. We explored associations between EEG and patterns of LTCI using Wilcoxon rank-sum tests and Spearman's rank correlations.

RESULTS

Of 521 Vanderbilt patients enrolled in the parent study, 24 had EEG recordings during admission. Ten survivors had EEG tracings available and completed follow-up cognitive testing. All but one inpatient EEG showed generalized background slowing. All patients demonstrated cognitive impairment in at least one domain at follow-up. The most common deficits occurred in delayed memory (DM-median index 62) and visuospatial/constructional (VC-median index 69) domains. Relative alpha power correlated with VC score (ρ = 0.78, P = .008). Peak interhemispheric coherence correlated negatively with DM (ρ = -0.81, P = .018).

CONCLUSIONS

Quantitative EEG features during critical illness correlated with domain-specific cognitive performance in our small cohort of ICU survivors. Further study in larger prospective cohorts is required to determine whether these relationships hold.

SIGNIFICANCE

EEG may serve as a prognostic biomarker predicting patterns of long-term cognitive impairment.

Design and Rationale of the Sevoflurane for Sedation in Acute Respiratory Distress Syndrome (SESAR) Randomized Controlled Trial

Preclinical studies have shown that volatile anesthetics may have beneficial effects on injured lungs, and pilot clinical data support improved arterial oxygenation, attenuated inflammation, and decreased lung epithelial injury in patients with acute respiratory distress syndrome (ARDS) receiving inhaled sevoflurane compared to intravenous midazolam. Whether sevoflurane is effective in improving clinical outcomes among patients with ARDS is unknown, and the benefits and risks of inhaled sedation in ARDS require further evaluation. Here, we describe the SESAR (Sevoflurane for Sedation in ARDS) trial designed to address this question. SESAR is a two-arm, investigator-initiated, multicenter, prospective, randomized, stratified, parallel-group clinical trial with blinded outcome assessment designed to test the efficacy of sedation with sevoflurane compared to intravenous propofol in patients with moderate to severe ARDS. The primary outcome is the number of days alive and off the ventilator at 28 days, considering death as a competing event, and the key secondary outcome is 90 day survival. The planned enrollment is 700 adult participants at 37 French academic and non-academic centers. Safety and long-term outcomes will be evaluated, and biomarker measurements will help better understand mechanisms of action. The trial is funded by the French Ministry of Health, the European Society of Anaesthesiology, and Sedana Medical.

DNA methylation in the inflammatory genes after neurosurgery and diagnostic ability of post-operative delirium

The pathophysiological mechanisms of postoperative delirium (POD) are still not clear, and no reliable biomarker is available to differentiate those with and without POD. Pre- and post-surgery blood from epilepsy subjects undergoing neurosurgery were collected. DNA methylation (DNAm) levels of the TNF gene, IL1B gene, and IL6 gene by the Illumina EPIC array method, and DNAm levels of the TNF gene by pyrosequencing, were analyzed. Blood from 37 subjects were analyzed by the EPIC array method, and blood from 27 subjects were analyzed by pyrosequencing. Several CpGs in the TNF gene in preoperative blood showed a negative correlation between their DNAm and age both in the POD group and in the non-POD group. However, these negative correlations were observed only in the POD group after neurosurgery. Neurosurgery significantly altered DNAm levels at 17 out of 24 CpG sites on the TNF gene, 8 out of 14 CpG sites on the IL1B gene, and 4 out of 14 CpG sites on the IL6 gene. Furthermore, it was found that the Inflammatory Methylation Index (IMI), which was based on the post-surgery DNAm levels at the selected five CpG sites, can be a potential detection tool for delirium with moderate accuracy; area under the curve (AUC) value was 0.84. The moderate accuracy of this IMI was replicated using another cohort from our previous study, in which the AUC was 0.79. Our findings provide further evidence of the potential role of epigenetics and inflammation in the pathophysiology of delirium.

Association of Delirium during Critical Illness With Mortality: Multicenter Prospective Cohort Study

BACKGROUND

The temporal association of delirium during critical illness with mortality is unclear, along with the associations of hypoactive and hyperactive motoric subtypes of delirium with mortality. We aimed to evaluate the relationship of delirium during critical illness, including hypoactive and hyperactive motoric subtypes, with mortality in the hospital and after discharge up to 1 year.

METHODS

We analyzed a prospective cohort study of adults with respiratory failure and/or shock admitted to university, community, and Veterans Affairs hospitals. We assessed patients using the Richmond Agitation-Sedation Scale and the Confusion Assessment Method for the intensive care unit (ICU) and defined the motoric subtype according to the corresponding Richmond Agitation-Sedation Scale if delirium was present. We used Cox proportional hazard models, adjusted for baseline characteristics, coma, and daily hospital events, to determine whether delirium on a given day predicted mortality the following day in patients in the hospital and also to determine whether delirium presence and duration predicted mortality after discharge up to 1 year in patients who survived to hospital discharge. We performed similar analyses for hypoactive and hyperactive subtypes of delirium.

RESULTS

Among 1040 critically ill patients, 214 (21%) died in the hospital and 204 (20%) died out-of-hospital by 1 year. Delirium was common, occurring in 740 (71%) patients for a median (interquartile range [IQR]) of 4 (2-7) days. Hypoactive delirium occurred in 733 (70%) patients, and hyperactive occurred in 185 (18%) patients, with a median (IQR) of 3 (2-7) days and 1 (1-2) days, respectively. Delirium on a given day (hazard ratio [HR], 2.87; 95% confidence interval [CI], 1.32-6.21; P = .008), in particular the hypoactive subtype (HR, 3.35; 95% CI, 1.51-7.46; P = .003), was independently associated with an increased risk of death the following day in the hospital. Hyperactive delirium was not associated with an increased risk of death in the hospital (HR, 4.00; 95% CI, 0.49-32.51; P = .19). Among hospital survivors, neither delirium presence (HR, 1.01; 95% CI, 0.82-1.24; P = .95) nor duration (HR, 0.99; 95% CI, 0.97-1.01; P = .56), regardless of motoric subtype, was associated with mortality after hospital discharge up to 1 year.

CONCLUSIONS

Delirium during critical illness is associated with nearly a 3-fold increased risk of death the following day for patients in the hospital but is not associated with mortality after hospital discharge. This finding appears primarily driven by the hypoactive motoric subtype. The independent relationship between delirium and mortality occurs early during critical illness but does not persist after hospital discharge.

Delirium in critical illness: clinical manifestations, outcomes, and management

Delirium is the most common manifestation of brain dysfunction in critically ill patients. In the intensive care unit (ICU), duration of delirium is independently predictive of excess death, length of stay, cost of care, and acquired dementia. There are numerous neurotransmitter/functional and/or injury-causing hypotheses rather than a unifying mechanism for delirium. Without using a validated delirium instrument, delirium can be misdiagnosed (under, but also overdiagnosed and trivialized), supporting the recommendation to use a monitoring instrument routinely. The best-validated ICU bedside instruments are CAM-ICU and ICDSC, both of which also detect subsyndromal delirium. Both tools have some inherent limitations in the neurologically injured patients, yet still provide valuable information about delirium once the sequelae of the primary injury settle into a new post-injury baseline. Now it is known that antipsychotics and other psychoactive medications do not reliably improve brain function in critically ill delirious patients. ICU teams should systematically screen for predisposing and precipitating factors. These include exacerbations of cardiac/respiratory failure or sepsis, metabolic disturbances (hypoglycemia, dysnatremia, uremia and ammonemia) receipt of psychoactive medications, and sensory deprivation through prolonged immobilization, uncorrected vision and hearing deficits, poor sleep hygiene, and isolation from loved ones so common during COVID-19 pandemic. The ABCDEF (A2F) bundle is a means to facilitate implementation of the 2018 Pain, Agitation/Sedation, Delirium, Immobility, and Sleep Disruption in Adult Patients in the ICU (PADIS) Guidelines. In over 25,000 patients across nearly 100 institutions, the A2F bundle has been shown in a dose-response fashion (i.e., greater bundle compliance) to yield improved survival, length of stay, coma and delirium duration, cost, and less ICU bounce-backs and discharge to nursing homes.

A Predictive Model of Reintubation after Cardiac Surgery Using the Electronic Health Record

BACKGROUND

Reintubation and prolonged intubation after cardiac surgery are associated with significant complications. Despite these competing risks, providers frequently extubate patients with limited insight into the risk of reintubation at the time of extubation. Achieving timely, successful extubation remains a significant clinical challenge.

METHODS

Based on an analysis of 2835 patients undergoing cardiac surgery at our institution between November 2017 and July 2020, we developed a model for an individual's risk of reintubation at the time of extubation. Predictors were screened for inclusion in the model based on clinical plausibility and availability at the time of extubation. Rigorous data reduction methods were used to create a model that could be easily integrated into clinical workflow at the time of extubation.

RESULTS

In total, 90 patients (3.2%) were reintubated within 48 hours of initial extubation. Number of inotropes [1 (adjusted odds ratio (OR), 15.4; 95% confidence interval (CI) 6.5-47.6; p <.001), ≥2 (OR, 62.7; 95% CI 14.3-279.5; p<.001)]; dexmedetomidine dose (OR, 3.0 [per mcg/kg/h]; 95% CI 1.9-4.7; p <.001), time to extubation (OR, 1.04 [per six hour increase]; 95% CI 1.02-1.05; p <.001), and respiratory rate (OR, 1.04 [per breath/min.]; 95% CI 1.01-1.07; p <.001) were the best predictors for the model, which displayed excellent discriminative capacity (the area under the receiver operating characteristic, 0.86; 95% CI 0.84-0.89).

CONCLUSIONS

An improved understanding of reintubation risk may lead to improved decision-making at extubation and targeted interventions to decrease reintubation in high-risk patients. Future studies are needed to optimize timing of extubation.

Prospective Validation of the Preschool Confusion Assessment Method for the ICU to Screen for Delirium in Infants Less Than 6 Months Old

OBJECTIVES

ICU delirium is a predictor of greater morbidity and higher mortality in the pediatric population. The diagnostic obstacles and validity of delirium monitoring among neonates and young infants have yet to be fully delineated. We sought to validate the Preschool Confusion Assessment Method for the ICU in neonates and young infants and determine delirium prevalence in this young population.

DESIGN

Prospective cohort study to validate the Preschool Confusion Assessment Method for the ICU for the assessment of ICU delirium in neonates and young infants compared with the reference standard, Child and Adolescent Psychiatry.

SETTING

Tertiary medical center PICU, including medical, surgical, and cardiac patients.

PARTICIPANTS

Infants less than 6 months old admitted to the PICU regardless of admission diagnosis.

MEASUREMENTS AND MAIN RESULTS

We enrolled 49 patients with a median age of 1.8 months (interquartile range, 0.7-4.1 mo), 82% requiring mechanical ventilation. Enrolled patients were assessed for delirium in blinded-fashion by the research team using the Preschool Confusion Assessment Method for the ICU and independently assessed by the psychiatry reference rater using Diagnostic and Statistical Manual of Mental Disorders-5 criteria. A total of 189 paired assessments were completed, and the Preschool Confusion Assessment Method for the ICU performed with a sensitivity of 95% (95% CI, 89-100%), specificity of 81% (68-90%), "negative and positive predictive values" of 97% (94-100%) and 69% (55-79%), respectively, compared with the reference rater. Delirium prevalence was 47%, with higher rates of 61% observed among neonates (< 1 mo old) and 39% among infants 1-6 months old.

CONCLUSIONS

The Preschool Confusion Assessment Method for the ICU is a valid screening tool for delirium monitoring in infants less than 6 months old. Delirium screening was feasible in this population despite evolving neurocognition and arousal architecture. ICU delirium was prevalent among infants. The consequence of acute brain dysfunction during crucial neurocognitive development remains unclear. Future studies are necessary to determine the long-term impact of ICU delirium and strategies to reduce associated harm in critically ill infants.

Nutritional Risk at intensive care unit admission and outcomes in survivors of critical illness

BACKGROUND AND AIMS

Risk factors for poor outcomes after critical illness are incompletely understood. While nutritional risk is associated with mortality in critically ill patients, its association with disability, cognitive, and health-related quality of life is unclear in survivors of critical illness. This study's objective was to determine whether greater nutritional risk at ICU admission is associated with greater disability, worse cognition, and worse HRQOL at 3 and 12-month follow-up.

METHODS

We enrolled adults (≥18 years of age) with respiratory failure or shock treated in medical and surgical intensive care units from two U.S. centers. We measured nutritional risk using the modified Nutrition Risk in Critically Ill (mNUTRIC) score (range 0-9 [highest risk]) at intensive care unit admission. We measured associations between mNUTRIC scores and discharge destination, disability in basic activities of daily living (ADLs) using the Katz ADL, instrumental ADLs using the Functional Activities Questionnaire (FAQ), global cognition using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), executive function using the Trail Making Test Part B (Trails B), and health-related quality of life using the SF-36, adjusting for sex, education, BMI, baseline frailty, disability, and cognition, severity of illness, days of delirium, coma, and mechanical ventilation.

RESULTS

Of the 821 patients enrolled in the ICU, 636 patients survived to hospital discharge. We assessed outcomes in 448 of 535 survivors (84%) at 3 months and 382 of 476 survivors (80%) at 12 months. Higher mNUTRIC scores predicted greater odds of discharge to an institution (OR 2.0, 95% CI: 1.6 to 2.6; P < 0.01). Higher mNUTRIC scores were associated with a trend towards greater disability in basic activities of daily living (IRR 1.3, 95% CI 1.0 to 1.7) at 3 months that did not reach significance (p = 0.09) with no association demonstrated at 12 months. There were no associations between mNUTRIC scores and FAQ, RBANS, or Trails B scores. mNUTRIC scores were inconsistently associated with SF-36 physical and mental component scale scores.

CONCLUSIONS

Greater nutritional risk at ICU admission is associated with disability in survivors of critical illness. Future studies should evaluate interventions in those at high nutritional risk as a means to speed recovery.

Motoric Subtypes of Delirium and Long-Term Functional and Mental Health Outcomes in Adults After Critical Illness

OBJECTIVES

Adult ICU survivors that experience delirium are at high risk for developing new functional disabilities and mental health disorders. We sought to determine if individual motoric subtypes of delirium are associated with worse disability, depression, and/or post-traumatic stress disorder in ICU survivors.

DESIGN

Secondary analysis of a prospective multicenter cohort study.

SETTING

Academic, community, and Veteran Affairs hospitals.

PATIENTS

Adult ICU survivors of respiratory failure and/or shock.

INTERVENTIONS

We assessed delirium and level of consciousness using the Confusion Assessment Method-ICU and Richmond Agitation and Sedation Scale daily during hospitalization. We classified delirium as hypoactive (Richmond Agitation and Sedation Scale ≤ 0) or hyperactive (Richmond Agitation and Sedation Scale > 0). At 3- and 12-month postdischarge, we assessed for dependence in activities of daily living and instrumental activities of daily living, symptoms of depression, and symptoms of post-traumatic stress disorder. Adjusting for baseline and inhospital covariates, multivariable regression examined the association of exposure to delirium motoric subtype and long-term outcomes.

MEASUREMENTS AND MAIN RESULTS

In our cohort of 556 adults with a median age of 62 years, hypoactive delirium was more common than hyperactive (68.9% vs 16.8%). Dependence on the activities of daily living was present in 37% at 3 months and 31% at 12 months, whereas dependence on instrumental activities of daily living was present in 63% at 3 months and 56% at 12 months. At both time points, depression and post-traumatic stress disorder rates were constant at 36% and 5%, respectively. Each additional day of hypoactive delirium was associated with higher instrumental activities of daily living dependence at 3 months only (0.24 points [95% CI, 0.07-0.41; p = 0.006]). There were no associations between the motoric delirium subtype and activities of daily living dependence, depression, or post-traumatic stress disorder.

CONCLUSIONS

Longer duration of hypoactive delirium, but not hyperactive, was associated with a minimal increase in early instrumental activities of daily living dependence scores in adult survivors of critical illness. Motoric delirium subtype was neither associated with early or late activities of daily living functional dependence or mental health outcomes, nor late instrumental activities of daily living functional dependence.

Dexmedetomidine or Propofol for Sedation in Mechanically Ventilated Adults with Sepsis

BACKGROUND

Guidelines currently recommend targeting light sedation with dexmedetomidine or propofol for adults receiving mechanical ventilation. Differences exist between these sedatives in arousability, immunity, and inflammation. Whether they affect outcomes differentially in mechanically ventilated adults with sepsis undergoing light sedation is unknown.

METHODS

In a multicenter, double-blind trial, we randomly assigned mechanically ventilated adults with sepsis to receive dexmedetomidine (0.2 to 1.5 μg per kilogram of body weight per hour) or propofol (5 to 50 μg per kilogram per minute), with doses adjusted by bedside nurses to achieve target sedation goals set by clinicians according to the Richmond Agitation-Sedation Scale (RASS, on which scores range from -5 [unresponsive] to +4 [combative]). The primary end point was days alive without delirium or coma during the 14-day intervention period. Secondary end points were ventilator-free days at 28 days, death at 90 days, and age-adjusted total score on the Telephone Interview for Cognitive Status questionnaire (TICS-T; scores range from 0 to 100, with a mean of 50±10 and lower scores indicating worse cognition) at 6 months.

RESULTS

Of 432 patients who underwent randomization, 422 were assigned to receive a trial drug and were included in the analyses - 214 patients received dexmedetomidine at a median dose of 0.27 μg per kilogram per hour, and 208 received propofol at a median dose of 10.21 μg per kilogram per minute. The median duration of receipt of the trial drugs was 3.0 days (interquartile range, 2.0 to 6.0), and the median RASS score was -2.0 (interquartile range, -3.0 to -1.0). We found no difference between dexmedetomidine and propofol in the number of days alive without delirium or coma (adjusted median, 10.7 vs. 10.8 days; odds ratio, 0.96; 95% confidence interval [CI], 0.74 to 1.26), ventilator-free days (adjusted median, 23.7 vs. 24.0 days; odds ratio, 0.98; 95% CI, 0.63 to 1.51), death at 90 days (38% vs. 39%; hazard ratio, 1.06; 95% CI, 0.74 to 1.52), or TICS-T score at 6 months (adjusted median score, 40.9 vs. 41.4; odds ratio, 0.94; 95% CI, 0.66 to 1.33). Safety end points were similar in the two groups.

CONCLUSIONS

Among mechanically ventilated adults with sepsis who were being treated with recommended light-sedation approaches, outcomes in patients who received dexmedetomidine did not differ from outcomes in those who received propofol. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT01739933.).

Worse Than Death: Survey of Public Perceptions of Disability Outcomes After Hypothetical Traumatic Brain Injury

OBJECTIVE

The aim of this study was to determine the health utility states of the most commonly used traumatic brain injury (TBI) clinical trial endpoint, the Extended Glasgow Outcome Scale (GOSE).

SUMMARY BACKGROUND DATA

Health utilities represent the strength of one's preferences under conditions of uncertainty. There are insufficient data to indicate how an individual would value levels of disability after a TBI.

METHODS

This was a cross-sectional web-based online convenience sampling adaptive survey. Using a standard gamble approach, participants evaluated their preferences for GOSE health states 1 year after a hypothetical TBI. The categorical GOSE was studied from vegetative state (GOSE2) to upper good recovery (GOSE8). Median (25th percentile, 75th percentile) health utility values for different GOSE states after TBI, ranging from -1 (worse than death) to 1 (full health), with 0 as reference (death).

RESULTS

Of 3508 eligible participants, 3235 (92.22%) completed the survey. Participants rated lower GOSE states as having lower utility, with some states rated as worse than death, though the relationship was nonlinear and intervals were unequal between health states. Over 75% of participants rated a vegetative state (GOSE2, absence of awareness and bedridden) and about 50% rated lower severe disability (GOSE3, housebound needing all-day assistance) as conditions worse than death.

CONCLUSIONS

In the largest investigation of public perceptions about post-TBI disability, we demonstrate unequally rated health states, with some states perceived as worse than death. Although limited by selection bias, these results may guide future comparative-effectiveness research and shared medical decision-making after neurologic injury.

Prevention and Management of Delirium in the Intensive Care Unit

Delirium is a debilitating form of brain dysfunction frequently encountered in the intensive care unit (ICU). It is associated with increased morbidity and mortality, longer lengths of stay, higher hospital costs, and cognitive impairment that persists long after hospital discharge. Predisposing factors include smoking, hypertension, cardiac disease, sepsis, and premorbid dementia. Precipitating factors include respiratory failure and shock, metabolic disturbances, prolonged mechanical ventilation, pain, immobility, and sedatives and adverse environmental conditions impairing vision, hearing, and sleep. Historically, antipsychotic medications were the mainstay of delirium treatment in the critically ill. Based on more recent literature, the current Society of Critical Care Medicine (SCCM) guidelines suggest against routine use of antipsychotics for delirium in critically ill adults. Other pharmacologic interventions (e.g., dexmedetomidine) are under investigation and their impact is not yet clear. Nonpharmacologic interventions thus remain the cornerstone of delirium management. This approach is summarized in the ABCDEF bundle (Assess, prevent, and manage pain; Both SAT and SBT; Choice of analgesia and sedation; Delirium: assess, prevent, and manage; Early mobility and exercise; Family engagement and empowerment). The implementation of this bundle reduces the odds of developing delirium and the chances of needing mechanical ventilation, yet there are challenges to its implementation. There is an urgent need for ongoing studies to more effectively mitigate risk factors and to better understand the pathobiology underlying ICU delirium so as to identify additional potential treatments. Further refinements of therapeutic options, from drugs to rehabilitation, are current areas ripe for study to improve the short- and long-term outcomes of critically ill patients with delirium.

Pharmacologic Management of Intensive Care Unit Delirium: Clinical Prescribing Practices and Outcomes in More Than 8500 Patient Encounters

BACKGROUND

Pharmacologic agents are frequently utilized for management of intensive care unit (ICU) delirium, yet prescribing patterns and impact of medication choices on patient outcomes are poorly described. We sought to describe prescribing practices for management of ICU delirium and investigate the independent association of medication choice on key in-hospital outcomes including delirium resolution, in-hospital mortality, and days alive and free of the ICU or hospital.

METHODS

A retrospective study of delirious adult ICU patients at a tertiary academic medical center. Data were obtained regarding daily mental status (normal, delirious, and comatose), pharmacologic treatment, hospital course, and survival via electronic health record. Daily transition models were constructed to assess the independent association of previous day mental status and medication administration on mental status the following day and in-hospital mortality, after adjusting for prespecified covariates. Linear regression models investigated the association of medication administration on days alive and free of the ICU or the hospital during the first 30 days after ICU admission.

RESULTS

We identified 8591 encounters of ICU delirium. Half (45.6%) of patients received pharmacologic treatment for delirium, including 45.4% receiving antipsychotics, 2.2% guanfacine, and 0.84% valproic acid. Median highest Richmond Agitation-Sedation Scale (RASS) score was 1 (0, 1) in patients initiated on medications and 0 (-1, 0) for nonrecipients. Haloperidol, olanzapine, and quetiapine comprised >97% of antipsychotics utilized with 48% receiving 2 or more and 20.6% continued on antipsychotic medications at hospital discharge. Haloperidol and olanzapine were associated with greater odds of continued delirium (odds ratio [OR], 1.48; 95% confidence interval [95% CI], 1.30-1.65; P < .001 and OR, 1.37; 95% CI, 1.20-1.56; P = .003, respectively) and increased hazard of in-hospital mortality (hazard ratio [HR], 1.46; 95% CI, 1.10-1.93; P = .01 and HR, 1.67; 95% CI, 1.14-2.45; P = .01, respectively) while quetiapine showed a decreased hazard of in-hospital mortality (HR, 0.58; 95% CI, 0.40-0.84; P = .01). Haloperidol, olanzapine, and quetiapine were associated with fewer days alive and free of hospitalization (all P < .001). There was no significant association of any antipsychotic medication with days alive and free of the ICU. Neither guanfacine nor valproic acid were associated with in-hospital outcomes examined.

CONCLUSIONS

Pharmacologic interventions for management of ICU delirium are common, most often with antipsychotics, and frequently continued at hospital discharge. These medications may not portend benefit, may introduce additional harm, and should be used with caution for delirium management. Continuation of these medications through hospitalization and discharge draws into question their safety and role in patient recovery.

Prevalence and risk factors for delirium in critically ill patients with COVID-19 (COVID-D): a multicentre cohort study

Background

To date, 750 000 patients with COVID-19 worldwide have required mechanical ventilation and thus are at high risk of acute brain dysfunction (coma and delirium). We aimed to investigate the prevalence of delirium and coma, and risk factors for delirium in critically ill patients with COVID-19, to aid the development of strategies to mitigate delirium and associated sequelae.

Methods

This multicentre cohort study included 69 adult intensive care units (ICUs), across 14 countries. We included all patients (aged ≥18 years) admitted to participating ICUs with severe acute respiratory syndrome coronavirus 2 infection before April 28, 2020. Patients who were moribund or had life-support measures withdrawn within 24 h of ICU admission, prisoners, patients with pre-existing mental illness, neurodegenerative disorders, congenital or acquired brain damage, hepatic coma, drug overdose, suicide attempt, or those who were blind or deaf were excluded. We collected de-identified data from electronic health records on patient demographics, delirium and coma assessments, and management strategies for a 21-day period. Additional data on ventilator support, ICU length of stay, and vital status was collected for a 28-day period. The primary outcome was to determine the prevalence of delirium and coma and to investigate any associated risk factors associated with development of delirium the next day. We also investigated predictors of number of days alive without delirium or coma. These outcomes were investigated using multivariable regression.

Findings

Between Jan 20 and April 28, 2020, 4530 patients with COVID-19 were admitted to 69 ICUs, of whom 2088 patients were included in the study cohort. The median age of patients was 64 years (IQR 54 to 71) with a median Simplified Acute Physiology Score (SAPS) II of 40·0 (30·0 to 53·0). 1397 (66·9%) of 2088 patients were invasively mechanically ventilated on the day of ICU admission and 1827 (87·5%) were invasively mechanical ventilated at some point during hospitalisation. Infusion with sedatives while on mechanical ventilation was common: 1337 (64·0%) of 2088 patients were given benzodiazepines for a median of 7·0 days (4·0 to 12·0) and 1481 (70·9%) were given propofol for a median of 7·0 days (4·0 to 11·0). Median Richmond Agitation–Sedation Scale score while on invasive mechanical ventilation was –4 (–5 to –3). 1704 (81·6%) of 2088 patients were comatose for a median of 10·0 days (6·0 to 15·0) and 1147 (54·9%) were delirious for a median of 3·0 days (2·0 to 6·0). Mechanical ventilation, use of restraints, and benzodiazepine, opioid, and vasopressor infusions, and antipsychotics were each associated with a higher risk of delirium the next day (all p≤0·04), whereas family visitation (in person or virtual) was associated with a lower risk of delirium (p<0·0001). During the 21-day study period, patients were alive without delirium or coma for a median of 5·0 days (0·0 to 14·0). At baseline, older age, higher SAPS II scores, male sex, smoking or alcohol abuse, use of vasopressors on day 1, and invasive mechanical ventilation on day 1 were independently associated with fewer days alive and free of delirium and coma (all p<0·01). 601 (28·8%) of 2088 patients died within 28 days of admission, with most of those deaths occurring in the ICU.

Interpretation

Acute brain dysfunction was highly prevalent and prolonged in critically ill patients with COVID-19. Benzodiazepine use and lack of family visitation were identified as modifiable risk factors for delirium, and thus these data present an opportunity to reduce acute brain dysfunction in patients with COVID-19.

Funding

None.

Translations

For the French and Spanish translations of the abstract see Supplementary Materials section.

Depression predicts long-term cognitive impairment in survivors of critical illness

INTRODUCTION

Intensive care unit (ICU) survivorship is associated with long-term cognitive impairment (LTCI). Our work has found post-ICU depression in up to 30% and posttraumatic stress disorder (PTSD) in up to 10% of ICU survivors. We hypothesized that post-ICU depression and PTSD are independently associated with LTCI in ICU survivors.

METHODS

This is a five-center nested prospective cohort of critically ill patients admitted to medical and surgical ICUs who underwent neuropsychological assessments at 3 and 12 months posthospital discharge. Our primary outcome was global cognition using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and Trail Making Test, Part B, a test of executive functioning, at 3- and 12-month follow-up. Our independent variables were Beck Depression Inventory II and the PTSD Checklist-Specific Version measured at 3 and 12 months. We performed multivariable linear regression models controlling for covariates such as age, years of education, preexisting cognitive impairment, comorbidities, ventilator days, hypoxemia episodes, and days of delirium or coma.

RESULTS

Of 1,047 patients in the combined cohort, 679 were alive and available for follow-up at 3 months. A total of 590 (87%) ICU survivors completed at least one 3-month assessment, and of the 554 who survived to 12 months, 519 (94%) completed both a 3- and 12-month assessment with a median age of 61 years (52-70 years) and mean daily Sequential Organ Failure Assessment score of 6 (4-8), 520 (88%) were mechanically ventilated, and 420 (71%) were with delirium. Of these, 113 (19%) had PTSD and 187 (32%) had depression at 3 months with similar rates at 12 months. Depression at 3 months was associated with lower 3-month RBANS (coefficient, -2.25; -3.10 to -1.39) and lower Trails B scores at both 3 months (odds ratio, 0.69; 0.56-0.85) and 12 months (odds ratio, 0.66; 0.52-0.84). Posttraumatic stress disorder at 3 months had no association with RBANS or Trails B scores at 3 or 12 months.

CONCLUSION

Early post-ICU depression, but not PTSD, is independently associated with coexisting LTCI, even when controlling for past ICU delirium. Treatment for early depression represents a novel intervention area for LTCI prevention in ICU survivors.

LEVEL OF EVIDENCE

Prognostic/epidemiological, level III.

Statistical analysis plan for the Maximizing the Efficacy of Sedation and Reducing Neurological Dysfunction and Mortality in Septic Patients with Acute Respiratory Failure trial

BACKGROUND: The best sedative medication to reduce delirium, mortality and long term brain dysfunction in mechanically ventilated septic patients is unclear. This multicentre, double-blind, randomised trial investigates the short term and long term effects of dexmedetomidine versus propofol for sedation in mechanically ventilated severely septic patients. OBJECTIVES: To describe the statistical analysis plan for this randomised clinical trial comprehensively and place it in the public domain before unblinding. METHODS: To ensure that analyses are not selectively reported, we developed a comprehensive statistical analysis plan before unblinding. This trial has an enrolment target of 420 severely septic and mechanically ventilated adult patients, randomly assigned to dexmedetomidine or propofol in a 1:1 ratio. Enrolment was completed in January 2019, and the study was estimated to be completed in September 2019. The primary endpoint is days alive without delirium or coma during first 14 study days. Secondary outcomes include 28-day ventilator-free days, 90-day all-cause mortality and cognitive function at 180 days. Time frames all begin on the day of randomisation. All analyses will be conducted on an intention-to-treat basis. CONCLUSION: This study will compare the effects of two sedatives in mechanically ventilated severely septic patients. In keeping with the guidance on statistical principles for clinical trials, we have developed a comprehensive statistical analysis plan by which we will adhere, as this will avoid bias and support transparency and reproducibility. TRIAL REGISTRATION: ClinicalTrials.gov (NCT01739933).

Statistical analysis plan for the Maximizing the Efficacy of Sedation and Reducing Neurological Dysfunction and Mortality in Septic Patients with Acute Respiratory Failure trial

BACKGROUND

The best sedative medication to reduce delirium, mortality and long term brain dysfunction in mechanically ventilated septic patients is unclear. This multicentre, double-blind, randomised trial investigates the short term and long term effects of dexmedetomidine versus propofol for sedation in mechanically ventilated severely septic patients.

OBJECTIVES

To describe the statistical analysis plan for this randomised clinical trial comprehensively and place it in the public domain before unblinding.

METHODS

To ensure that analyses are not selectively reported, we developed a comprehensive statistical analysis plan before unblinding. This trial has an enrolment target of 420 severely septic and mechanically ventilated adult patients, randomly assigned to dexmedetomidine or propofol in a 1:1 ratio. Enrolment was completed in January 2019, and the study was estimated to be completed in September 2019. The primary endpoint is days alive without delirium or coma during first 14 study days. Secondary outcomes include 28-day ventilator-free days, 90-day all-cause mortality and cognitive function at 180 days. Time frames all begin on the day of randomisation. All analyses will be conducted on an intention-to-treat basis.

CONCLUSION

This study will compare the effects of two sedatives in mechanically ventilated severely septic patients. In keeping with the guidance on statistical principles for clinical trials, we have developed a comprehensive statistical analysis plan by which we will adhere, as this will avoid bias and support transparency and reproducibility.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT01739933).

A Survey of Charge Sensitivity and Charge Awareness Among Intensive Care Unit Providers in a Large Academic Medical Center

Little is known about charge sensitivity or charge awareness among intensive care unit (ICU) providers in the United States. In a survey of 295 ICU providers at a large, academic medical center, 92.5% of respondents agreed that controlling health care expenses is partly their responsibility. However, 87.4% of respondents reported that they did not know the charges for most of the tests and medications they prescribe. Among surveyed participants, the correct charge for a medical procedure or test was selected only 35% of the time. While ICU providers overwhelmingly agree that controlling expenses is their responsibility, charge awareness is low and likely limits their ability to make value-based decisions.

Association of neuronal repair biomarkers with delirium among survivors of critical illness

PURPOSE

Delirium is prevalent but with unclear pathogenesis. Neuronal injury repair pathways may be protective. We hypothesized that higher concentrations of neuronal repair biomarkers would be associated with decreased delirium in critically ill patients.

MATERIALS AND METHODS

We performed a nested study of hospital survivors within a prospective cohort that enrolled patients within 72 h of respiratory failure or shock. We measured plasma concentrations of ubiquitin carboxyl-terminal-esterase-L1 (UCHL1) and brain-derived neurotrophic factor (BDNF) from blood collected at enrollment. Delirium was assessed twice daily using the CAM-ICU. Multivariable regression was used to examine the associations between biomarkers and delirium prevalence/duration, adjusting for covariates and interactions with age and IL-6 plasma concentration.

RESULTS

We included 427 patients with a median age of 59 years (IQR 48-69) and APACHE II score of 25 (IQR 19-30). Higher plasma concentration of UCHL1 on admission was independently associated with lower prevalence of delirium (p = .04) but not associated with duration of delirium (p = .06). BDNF plasma concentration was not associated with prevalence (p = .26) or duration of delirium (p = .36).

CONCLUSIONS

During critical illness, higher UCHL1 plasma concentration is associated with lower prevalence of delirium; BDNF plasma concentration is not associated with delirium. Clinical trial number: NCT00392795; https://clinicaltrials.gov/ct2/show/NCT00392795.

Intensive Care Unit Enhanced Recovery Pathway for Patients Undergoing Orthotopic Liver Transplants Recipients: A Prospective, Observational Study

BACKGROUND

Liver transplant recipients continue to have high perioperative resource utilization and prolonged length of stay despite improvements in perioperative care. Enhanced recovery pathways have been shown in other surgical populations to produce reductions in hospital resource utilization.

METHODS

A prospective, observational study was performed to examine the effect of an enhanced recovery pathway for postoperative care after liver transplantation. Outcomes from patients undergoing liver transplantation from November 1, 2013, to October 31, 2014, managed by the pathway were compared to transplant recipients from the year before pathway implementation. Multivariable regression analysis was used to assess the association of the clinical pathway on clinical outcomes.

RESULTS

The intervention and control groups included 141 and 106 patients, respectively. There were no demographic differences between the control and intervention group including no differences between the length of surgery and cold ischemic time. Median intensive care unit length of stay was reduced from 4.4 to 2.6 days (P < .001). The intervention group had a higher likelihood of earlier discharge (hazard ratio [95% CI], 2.01 [1.55-2.62]; P < .001), and a 69% and 65% lower odds of receiving a plasma (P < .001) or packed red blood cell (P < .001) transfusion. There was no significant effect on hospital mortality (P = .40), intensive care unit readmission rates (P = .75), or postoperative infections (urinary traction infections: P = .09; pneumonia: P = .27).

CONCLUSIONS

An enhanced recovery pathway focused on milestone-based elements of intensive care unit management and predetermined management triggers including hemodynamic goals, fluid therapy, perioperative antibiotics, glycemic control, and standardized transfusion triggers led to reductions in intensive care unit length of stay without an increase in perioperative complications.

Special Considerations for the Aging Brain and Perioperative Neurocognitive Dysfunction

Postoperative delirium and postoperative cognitive dysfunction (POCD) occur commonly in older adults after surgery and are frequently underrecognized. Delirium has been associated with worse outcomes, and both delirium and cognitive dysfunction increase the risk of long-term cognitive decline. Although the pathophysiology of delirium and POCD have not been clearly defined, risk factors for both include increasing age, lower levels of education, and baseline cognitive impairment. In addition, developing delirium increases the risk of POCD. This article examines interventions that may reduce the risk of developing delirium and POCD and improve long-term recovery and outcomes in the vulnerable older population.

Delirium Monitoring: Yes or No? That Is The Question

Delirium, one of the most common manifestations of acute brain dysfunction, is a serious complication in patients receiving care throughout the hospital and a strong predictor of worse outcome. Although delirium monitoring is advocated in numerous evidence-based guidelines as part of routine clinical care, it is still not widely and consistently performed at the bedside in different patient care settings. In a debate on delirium monitoring in hospitalized patients at the 7th American Delirium Society meeting in Nashville, Tennessee, June 2017, areas related to the feasibility, acceptability, and effectiveness of routine delirium monitoring of hospitalized patients were identified, and arguments both for (pro) and against (con) the practice were presented. These arguments and others arising in the discussion were subsequently expanded. The goals were to present a conversation among clinicians and researchers from different settings and to identify the evidence-practice gaps for delirium monitoring for future research and organizational quality improvement programs. Further research is needed to determine whether or not delirium monitoring should become routine clinical care for every patient in every hospital setting.

Melatonin in Critical Care

Melatonin is involved in regulation of a variety of physiologic functions, including circadian rhythm, reproduction, mood, and immune function. Exogenous melatonin has demonstrated many clinical effects. Numerous clinical studies have documented improved sleep quality following administration of exogenous melatonin. Recent studies also demonstrate the analgesic, anxiolytic, antiinflammatory, and antioxidative effects of melatonin. This article reviews the principal properties of melatonin and how these could find clinical applications in care of the critically ill patients.

A Brief Informant Screening Instrument for Dementia in the ICU: The Diagnostic Accuracy of the AD8 in Critically Ill Adults Suspected of Having Pre-Existing Dementia

BACKGROUND/AIM

The diagnostic accuracy of brief informant screening instruments to detect dementia in critically ill adults is unknown. We sought to determine the diagnostic accuracy of the 2- to 3-min Ascertain Dementia 8 (AD8) completed by surrogates in detecting dementia among critically ill adults suspected of having pre-existing dementia by comparing it to the Clinical Dementia Rating Scale (CDR).

METHODS

This substudy of BRAIN-ICU included a subgroup of 75 critically ill medical/surgical patients determined to be at medium risk of having pre-existing dementia (Informant Questionnaire on Cognitive Decline in the Elderly [IQCODE] score ≥3.3). We calculated the sensitivity, specificity, positive and negative predictive values (PPV and NPV), and AUC for the standard AD8 cutoff of ≥2 versus the reference standard CDR score of ≥1 for mild dementia.

RESULTS

By the CDR, 38 patients had very mild or no dementia and 37 had mild dementia or greater. For diagnosing mild dementia, the AD8 had a sensitivity of 97% (95% CI 86-100), a specificity of 16% (6-31), a PPV of 53% (40-65), an NPV of 86% (42-100), and an AUC of 0.738 (0.626-0.850).

CONCLUSIONS

Among critically ill patients judged at risk for pre-existing dementia, the 2- to 3-min AD8 is highly sensitive and has a high NPV. These data indicate that the brief tool can serve to rule out dementia in a specific patient population.

Haloperidol and Ziprasidone for Treatment of Delirium in Critical Illness

BACKGROUND

There are conflicting data on the effects of antipsychotic medications on delirium in patients in the intensive care unit (ICU).

METHODS

In a randomized, double-blind, placebo-controlled trial, we assigned patients with acute respiratory failure or shock and hypoactive or hyperactive delirium to receive intravenous boluses of haloperidol (maximum dose, 20 mg daily), ziprasidone (maximum dose, 40 mg daily), or placebo. The volume and dose of a trial drug or placebo was halved or doubled at 12-hour intervals on the basis of the presence or absence of delirium, as detected with the use of the Confusion Assessment Method for the ICU, and of side effects of the intervention. The primary end point was the number of days alive without delirium or coma during the 14-day intervention period. Secondary end points included 30-day and 90-day survival, time to freedom from mechanical ventilation, and time to ICU and hospital discharge. Safety end points included extrapyramidal symptoms and excessive sedation.

RESULTS

Written informed consent was obtained from 1183 patients or their authorized representatives. Delirium developed in 566 patients (48%), of whom 89% had hypoactive delirium and 11% had hyperactive delirium. Of the 566 patients, 184 were randomly assigned to receive placebo, 192 to receive haloperidol, and 190 to receive ziprasidone. The median duration of exposure to a trial drug or placebo was 4 days (interquartile range, 3 to 7). The median number of days alive without delirium or coma was 8.5 (95% confidence interval [CI], 5.6 to 9.9) in the placebo group, 7.9 (95% CI, 4.4 to 9.6) in the haloperidol group, and 8.7 (95% CI, 5.9 to 10.0) in the ziprasidone group (P=0.26 for overall effect across trial groups). The use of haloperidol or ziprasidone, as compared with placebo, had no significant effect on the primary end point (odds ratios, 0.88 [95% CI, 0.64 to 1.21] and 1.04 [95% CI, 0.73 to 1.48], respectively). There were no significant between-group differences with respect to the secondary end points or the frequency of extrapyramidal symptoms.

CONCLUSIONS

The use of haloperidol or ziprasidone, as compared with placebo, in patients with acute respiratory failure or shock and hypoactive or hyperactive delirium in the ICU did not significantly alter the duration of delirium. (Funded by the National Institutes of Health and the VA Geriatric Research Education and Clinical Center; MIND-USA ClinicalTrials.gov number, NCT01211522 .).

Antimicrobial exposure and the risk of delirium in critically ill patients

Background

Prior retrospective cross-sectional work has associated antimicrobials with a non-specific phrase: encephalopathy without seizures. The purpose of this study is to determine whether different classes of antimicrobials have differential associations with the daily risk of delirium after critical illness is adjusted for.

Methods

Our study was a nested cohort that enrolled non-neurological critically ill adults from a medical or surgical intensive care unit (ICU) with daily follow-up to 30 days. Our independent variable was exposure to previous-day antimicrobial class: beta-lactams (subclasses: penicillins, first- to third-generation cephalosporins, fourth-generation cephalosporins, and carbapenems), macrolides, fluoroquinolones, and other. We adjusted for baseline covariates (age, comorbidities, cognition scores, sepsis, and mechanical ventilation), previous-day covariates (delirium, doses of analgesics/sedatives, and antipsychotic use), and same-day covariates (illness severity). Our primary outcome of delirium was measured by using the Confusion Assessment Method for the ICU. A daily delirium logistic regression model was used with an ICU time-restricted sensitivity analysis including daily adjustment for sepsis and mechanical ventilation.

Results

Of 418 ICU patients, delirium occurred in 308 (74%) with a median of 3 days (interquartile range 2–6) among those affected and 318 (76%) were exposed to antimicrobials. When covariates and ICU type were adjusted for, only first- to third-generation cephalosporins were associated with delirium (logistic regression model odds ratio (OR) = 2.2, 95% confidence interval (CI) 1.28–3.79, P = 0.004; sensitivity analysis OR = 2.13, 95% CI 1.10–4.10, P = 0.024).

Conclusions

First-, second-, and third-generation cephalosporins doubled the odds of delirium after baseline co-morbidities, ICU type, the course of critical care, and other competing antimicrobial and psychotropic medication risks were adjusted for. We did not find an association between delirium and cefepime, penicillins, carbapenems, fluoroquinolones, or macrolides.

Electronic supplementary material

The online version of this article (10.1186/s13054-018-2262-z) contains supplementary material, which is available to authorized users.

Effect of anaesthesia type on postoperative mortality and morbidities: a matched analysis of the NSQIP database

BACKGROUND

The anaesthetic technique may influence clinical outcomes, but inherent confounding and small effect sizes makes this challenging to study. We hypothesized that regional anaesthesia (RA) is associated with higher survival and fewer postoperative organ dysfunctions when compared with general anaesthesia (GA).

METHODS

We matched surgical procedures and type of anaesthesia using the US National Surgical Quality Improvement database, in which 264,421 received GA and 64,119 received RA. Procedures were matched according to Current Procedural Terminology (CPT) and ASA physical status classification. Our primary outcome was 30-day postoperative mortality and secondary outcomes were hospital length of stay, and postoperative organ system dysfunction. After matching, multiple regression analysis was used to examine associations between anaesthetic type and outcomes, adjusting for covariates.

RESULTS

After matching and adjusting for covariates, type of anaesthesia did not significantly impact 30-day mortality. RA was significantly associated with increased likelihood of early discharge (HR 1.09; P< 0.001), 47% lower odds of intraoperative complications, and 24% lower odds of respiratory complications. RA was also associated with 16% lower odds of developing deep vein thrombosis and 15% lower odds of developing any one postoperative complication (OR 0.85; P < 0.001). There was no evidence of an effect of anaesthesia technique on postoperative MI, stroke, renal complications, pulmonary embolism or peripheral nerve injury.

CONCLUSIONS

After adjusting for clinical and patient characteristic confounders, RA was associated with significantly lower odds of several postoperative complications, decreased hospital length of stay, but not mortality when compared with GA.

Clinical phenotypes of delirium during critical illness and severity of subsequent long-term cognitive impairment: a prospective cohort study

BACKGROUND

Delirium during critical illness results from numerous insults, which might be interconnected and yet individually contribute to long-term cognitive impairment. We sought to describe the prevalence and duration of clinical phenotypes of delirium (ie, phenotypes defined by clinical risk factors) and to understand associations between these clinical phenotypes and severity of subsequent long-term cognitive impairment.

METHODS

In this multicentre, prospective cohort study, we included adult (≥18 years) medical or surgical ICU patients with respiratory failure, shock, or both as part of two parallel studies: the Bringing to Light the Risk Factors and Incidence of Neuropsychological Dysfunction in ICU Survivors (BRAIN-ICU) study, and the Delirium and Dementia in Veterans Surviving ICU Care (MIND-ICU) study. We assessed patients at least once a day for delirium using the Confusion Assessment Method-ICU and identified a priori-defined, non-mutually exclusive phenotypes of delirium per the presence of hypoxia, sepsis, sedative exposure, or metabolic (eg, renal or hepatic) dysfunction. We considered delirium in the absence of hypoxia, sepsis, sedation, and metabolic dysfunction to be unclassified. 3 and 12 months after discharge, we assessed cognition with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). We used multiple linear regression to separately analyse associations between the duration of each phenotype of delirium and RBANS global cognition scores at 3-month and 12-month follow-up, adjusting for potential confounders.

FINDINGS

Between March 14, 2007, and May 27, 2010, 1048 participants were enrolled, eight of whom could not be analysed. Of 1040 participants, 708 survived to 3 months of follow-up and 628 to 12 months. Delirium was common, affecting 740 (71%) of 1040 participants at some point during the study and occurring on 4187 (31%) of all 13 434 participant-days. A single delirium phenotype was present on only 1355 (32%) of all 4187 participant-delirium days, whereas two or more phenotypes were present during 2832 (68%) delirium days. Sedative-associated delirium was most common (present during 2634 [63%] delirium days), and a longer duration of sedative-associated delirium predicted a worse RBANS global cognition score 12 months later, after adjusting for covariates (difference in score comparing 3 days vs 0 days: -4·03, 95% CI -7·80 to -0·26). Similarly, longer durations of hypoxic delirium (-3·76, 95% CI -7·16 to -0·37), septic delirium (-3·67, -7·13 to -0·22), and unclassified delirium (-4·70, -7·16 to -2·25) also predicted worse cognitive function at 12 months, whereas duration of metabolic delirium did not (1·14, -0·12 to 3·01).

INTERPRETATION

Our findings suggest that clinicians should consider sedative-associated, hypoxic, and septic delirium, which often co-occur, as distinct indicators of acute brain injury and seek to identify all potential risk factors that may impact on long-term cognitive impairment, especially those that are iatrogenic and potentially modifiable such as sedation.

FUNDING

National Institutes of Health and the Department of Veterans Affairs.