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Research Snapshot Theater: Quality and Patient Safety/Epidemiology - Outcomes, Adult

Prospective, Real-Time Measurement of ICU Activity and Strain With the Modified Activity Index Score

Sunday, March 22, 2026

11:00 AM - 12:00 PM Central Time

Location: Connections Central - RST 11

GM

Gabrielle Matias, MD

Disclosure(s): No relevant financial relationship(s) to disclose.
AR

Adovich S. Rivera, MD, PhD

Assistant Professor
Medical Social Sciences, Northwestern University Feinberg School of Medicine

Disclosure information not submitted.
YN

Yash Nelavelli, n/a

Pre-Medical Intern
Department of Biochemistry, University of Illinois Urbana-Champaign

Disclosure information not submitted.
SR

Susan Russell, MD

Associate Professor
Division of Pulmonary and Critical Care, Department of Medicine, Northwestern University Feinberg School of Medicine

Disclosure information not submitted.
AB

Allison Blackmur, RN

Nursing Manager
Northwestern Medicine

Disclosure information not submitted.
EH

Emily Hagen, RN

Nursing Manager
Northwestern Medicine

Disclosure information not submitted.
NN

Nandita R. Nadig, MD, MSCR

Associate Professor
Division of Pulmonary and Critical Care, Department of Medicine, Northwestern University Feinberg School of Medicine

Disclosure information not submitted.

Introduction: The past decade has had increasing focus on ICU strain – the mismatch between increased demand and an individual ICU or system’s capacity to deliver high-quality care. Prior works have found that strain negatively affects patient- and ICU-related outcomes, but prospectively collected data is limited. Our study adapted the COVID-era Activity Index (AI), a composite metric of ICU census and patient acuity, to develop a Modified Activity Index Scores (MAIS) – a real-time score with additional high-intensity care variables reflecting ICU activity in present-day. We hypothesized that patients admitted on days with higher MAIS are associated with worse patient outcomes.

Methods: This was a prospective, observational study of adult patients admitted to a 40-bed, academic medical ICU March-May 2025. Demographic and clinical variables were extracted from the electronic data warehouse. Additional data included reports of daily patient census, nurse staffing ratios, and volume of patients requiring high intensity care (e.g., multiple vasopressors, acutely post arrest, renal replacement therapy, etc). Daily MAIS was calculated with 16 variables divided over the number of staffed ICU beds. Each patient was assigned an admission MAIS: average of MAIS daily scores on the day of and day prior to admission. We tested if admission MAIS was associated with in-ICU mortality using logistic regression models adjusting for age, race, sex, DNR status, SOFA score, and weekend admission.

Results: We included a total of 398 unique admissions with mean age of 60 (SD 18.58), 50.8% males, 50.5% white, and a mean admission SOFA of 6.45 (SD 4.03). 26.1% were ventilated, 41.7% on vasopressors, 6.5% on renal replacement therapy, and 6% had an in-hospital cardiac arrest. Admission MAIS ranged from 0.41-1.51. The crude in-ICU mortality was 14.8% and median ICU length of stay (LOS) was 1.97 days (1.05-4.21). In adjusted analysis, higher admission MAIS was not associated with increased in-ICU mortality (OR 0.89, 0.71-1.14; p=0.36).

Conclusions: Our study demonstrates the feasibility of capturing MAIS as a real-time measurement of ICU activity, but this score was not associated with ICU mortality. Future work should evaluate MAIS’s association on efficiency outcomes such as ICU admission delays, LOS, or best practice adherence.