Does the ICU Requirement Score allow the poisoned patient to be safely managed without admission to the intensive care unit? – a validation cohort study

Abstract

Background

The Intensive care unit (ICU) Requirement Score (IRS) has been defined as identifying poisoned patients on hospital admission who do not require ICU referral, in an effort to reduce health expenses. However, this score has been poorly validated. We aimed to evaluate the IRS in a large cohort of poisoned patients.

Methods

We performed a single-center retrospective cohort study. IRS was calculated using clinical parameters obtained on admission including age, systolic blood pressure, heart rate, Glasgow coma score, intoxication type, co-morbidities (i.e., arrhythmia, cirrhosis, and respiratory insufficiency), and the combination of the intoxication with another reason for ICU admission. We evaluated the ability of IRS < 6 determined on admission to predict the lack of need for ICU treatment, defined as the need for mechanical ventilation, vasopressors, and/or renal replacement therapy in the first 24 h post-admission and/or death during the hospital stay. This score was compared to the usual prognostic scores, i.e., SAPS II and III, SOFA score, and PSS.

Results

During the 10-year study period, 2,514 poisoned patients were admitted, 1,011 excluded as requiring ICU treatment on admission, and 1,503 included. Among these patients, 232 met the endpoint whereas only 23/510 patients with IRS < 6 (4.5%) presented the endpoint and one patient died. The area under the curve of the IRS ROC curve was 0.736 (95% confidence interval (CI), 0.702–0.770). The negative predictive value of IRS < 6 was 95% (95% CI, 93–97), sensitivity 89% (95% CI, 85–93), specificity 38% (95% CI, 36–41), and positive predictive value 21% (95% CI, 18–24). IRS performance was similar to those of the other tested scores, which are however not readily available on admission.

Conclusion

Our data demonstrate the excellent negative predictive value of the IRS, allowing the exclusion of ICU requirements for poisoned patients with IRS < 6. IRS usefulness should be confirmed based on a prospective multicenter cohort study before extensive routine use.

Keywords:

• ICU Requirement Score
• poisoning
• predictive value
• validation
• cardiotoxicant

Acknowledgements

The authors would like to thank Mrs. Alison Good (Scotland, UK) for her helpful review of the manuscript.

Disclosure statement

The authors report no conflict of interest. The authors alone are responsible for the content and writing of this paper. The manuscript has been read and approved by all authors. The authors certify that the submission is not under review at any other publication. The authors certify that the authors have no other submissions and previous reports that might be regarded as overlapping with the current work. The authors declare no financial disclosures.

Author contributions

Study concept and design by Bruno Mégarbane. Patient management by Foued El Gharbi, Nathan Elbeze, Isabelle Malissin, Nicolas Deye, Sebastian Voicu, and Bruno Mégarbane. Analysis and interpretation of data by Foued El Gharbi Nathan Elbeze and Bruno Mégarbane. Drafting the manuscript by Foued El Gharbi and Bruno Mégarbane. Critical revision of the manuscript for important intellectual content by all authors.