Elsevier

Journal of Critical Care

Volume 35, October 2016, Pages 168-173
Journal of Critical Care

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Routine delirium monitoring is independently associated with a reduction of hospital mortality in critically ill surgical patients: A prospective, observational cohort study

https://doi.org/10.1016/j.jcrc.2016.05.028Get rights and content

Abstract

Purpose

Although delirium monitoring is recommended in international guidelines, there is lacking evidence for improved outcome due to it. We hypothesized that adherence to routine delirium monitoring would improve clinical outcome in adult critically ill patients.

Material and methods

We present the results of a prospective, noninterventional, observational cohort study that was conducted on 2 intensive care units (ICUs) of a tertiary care medical center between July and October 2007 (International Standard Registered Clinical Trial Record identifier: 76100795). We assessed delirium-monitoring and outcome parameters on a daily basis. Besides multivariate logistic and robust linear regression to analyze the relationship between delirium monitoring and outcome, we used the doubly robust augmented inverse probability weighting method for observational data to estimate effect sizes.

Results

Of 355 screened patients, we included 185 surgical ICU patients into our final analysis, of which 87 were mechanically ventilated. We found an independent association between delirium-monitoring adherence and in-hospital mortality for ventilated patients (odds ratio, 0.973; P= .041). Estimating the effect size, delirium monitoring indicated a reduction of 22% of in-hospital mortality if conducted 50% or more of ICU days per patient. The average ICU length of stay of 46 days was estimated to be reduced by 19 days (P= .031) if patients were sufficiently monitored.

Conclusion

Our data suggest an improved outcome for mechanically ventilated patients being screened for delirium in clinical routine.

Introduction

Delirium is defined as a disturbance in attention accompanied by a change in either cognition or consciousness that fluctuates over the course of the day and results from an underlying medical condition [1]. The incidence of delirium in critically ill patients has a wide variability depending on the mode of diagnosis, screening, and the patients under observation [2], [3], [4], [5]. Various studies have shown that delirious patients have an increased length of hospitalization [6], as well as a higher risk for long-term cognitive impairment [7] and functional impairments [8]. There are also studies stating a higher risk for mortality, which is a matter of current discussion [2]. The practice guideline of the Society of Critical Care Medicine [9] and national societies [10] recommend a frequent screening for delirium with particular assessment tools. These tools have been developed to allow a valid and reliable screening for delirium in clinical routine [3]. In comparison to a subjective, clinical evaluation, the use of validated scores improves the physician's and nurse's ability to detect delirium [11].

Delirium monitoring is part of the evidence-based organizational approach referred to as the “ABCDEF bundle” (Awakening and Breathing Coordination, Choice of sedatives, Delirium monitoring, Early mobility, Fast sleep) [12]. In this respect, feasibility and effectiveness have been shown for the implementation of parts of this bundle [13]: Considering the single features of the bundle, there is a body of literature favoring protocol-based sedation and showing negative effects of a continuous benzodiazepine-driven sedation [14], compared with a regime favoring nonbenzodiazepine sedation [15] and favoring less sedation [16]. In addition, early mobility has proven benefits for the patient [17]. In contrast, the distinct value of delirium monitoring in clinical routine has not been addressed so far and remains hypothetical. This might be one potential cause for the low implementation of delirium screening in clinical practice [18].

We set up a prospective cohort study to address this issue. We hypothesized that adherence to delirium monitoring, as an additional level of care, would result in a reduction of mortality in ventilated and nonventilated patients.

Section snippets

Materials and methods

In this prospective, observational, clinical trial (International Standard Registered Clinical Trial Record: 76100795) patients were included between July 2007 and October 2007. The data acquisition was performed on 2 intensive care units (ICUs) of a tertiary care medical center in Germany. The local ethics committee of the Charité–Universitätsmedizin Berlin, Berlin, Germany, approved the study and waived informed consent (ethical vote no. EA1/132/07, protocol no. 1.0, date of approval January

Cohort characteristics

Of 355 screened ICU patients, 185 participants were included in our final analysis (Fig. 2). Eighty-seven patients received MV, and 98 patients were NMV. The most common admission diagnosis, according to the International Classification of Diseases, Tenth Revision, was a malignancy of the digestive tract (65 [35.1%]), followed by severe injuries (35 [18.9%]). Other causes for admission were nonmalignant diseases of the digestive system (21 [11.4%]), diseases of the nervous system (16 [8.7%]),

Discussion

This single-center, cohort study of a surgical ICU population revealed that higher delirium-monitoring adherence was independently associated with a reduction of in-hospital mortality in MV patients.

Delirium monitoring is an integral part of guideline recommendations and ICU bundles [9]. In contrast, a point prevalence analysis within an international survey showed that 73% of observed patients were not monitored with a validated delirium score [18]. Despite the low implementation rates,

Conclusion

In conclusion, our data suggest that MV patients may profit from a daily delirium screening, as delirium-monitoring adherence was independently associated with lower in-hospital mortality. Nevertheless, considering the limitations of our study, these results should be confirmed in a broader ICU setting including other patient populations.

Acknowledgments

Alawi Luetz is a participant in the Charité Clinical Scientist Program funded by the Charité–Universitätsmedizin Berlin and the Berlin Institute of Health (internal institutional grant program).

References (31)

  • P.P. Pandharipande et al.

    Long-term cognitive impairment after critical illness

    N Engl J Med

    (2013)
  • J. Barr et al.

    Clinical practice guidelines for the management of pain, agitation, and delirium in adult patients in the intensive care unit

    Crit Care Med

    (2013)
  • J. Martin et al.

    Evidence and consensus-based German guidelines for the management of analgesia, sedation and delirium in intensive care--short version

    Ger Med Sci

    (2010)
  • J.W. Devlin et al.

    Use of a validated delirium assessment tool improves the ability of physicians to identify delirium in medical intensive care unit patients

    Crit Care Med

    (2007)
  • P. Pandharipande et al.

    Liberation and animation for ventilated ICU patients: the ABCDE bundle for the back-end of critical care

    Crit Care

    (2010)
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    The first 2 authors have contributed equally to this work.

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