Introduction: The Rothman Index (RI) is an objective measurement of a patient's overall condition, automatically generated from 26 variables including vital signs, laboratory data, cardiac rhythms, and nursing assessments. The purpose of this study was to assess the validity of RI scores in predicting surgical ICU (SICU) readmission rates and mortality.
Methods: We conducted a single-center retrospective analysis of surgical patients who were transferred from the SICU to the surgical floor from December 2014 to December 2016. Data included demographics, length of stay (LOS), mortality, and RI at multiple pretransfer and post-transfer time points.
Results: A total of 1,445 SICU patients were transferred to the surgical floor; 79 patients (5.5%) were readmitted within 48 hours of transfer. Mean age was 52 years, and 67% were male. Compared to controls, patients readmitted to the SICU within 48 hours experienced higher LOS (29 vs. 11 days, p < 0.05) as well as higher mortality (2.5% vs. 0.6%, p < 0.05). Patients requiring readmission also had a lower RI at 72, 48, and 24 hours before transfer as well as at 24 and 48 hours after transfer (p < 0.05 for all). Rothman Index scores were categorized into higher-risk (<40), medium-risk (40-65), and lower-risk groups (>65); RI scores at 24 hours before transfer were inversely proportional to overall mortality (RI < 40 = 2.5%, RI 40-65 = 0.3%, and RI > 65 = 0%; p < 0.05) and SICU readmission rates (RI < 40 = 9%, RI 40-65 = 5.2%, and RI > 65 = 2.8%; p < 0.05). Patients transferred with RI scores greater than 83 did not require SICU readmission within 48 hours.
Conclusion: Surgical ICU patients requiring readmission within 48 hours of transfer have a significantly higher mortality and longer LOS compared to those who do not. Patients requiring readmission also have significantly lower pretransfer and post-transfer RI scores compared to those who do not. Rothman Index scores may be used as a clinical tool for evaluating patients before transfer from the SICU. Prospective studies are warranted to further validate use of this technology.
Level of evidence: Retrospective database review, level III.