An Examination of Early Transfers to the ICU Based on a Physiologic Risk Score

Abstract

Unplanned transfers of patients from general medical-surgical wards to the Intensive Care Unit (ICU) can occur due to unexpected patient deterioration. Such patients tend to have higher mortality rates and longer lengths-of-stay than direct admissions to the ICU. As such, the medical community has invested substantial efforts in the development of patient risk scores with the intent to identify patients at risk of deterioration. In this work, we consider how one such risk score could be used to trigger proactive transfers to the ICU. We utilize a retrospective dataset from 21 Kaiser Permanente Northern California hospitals to estimate the potential benefit of transferring patients to the ICU at various levels of patient risk of deterioration. In order to reduce the sensitivity of our findings to key identification and modeling assumptions, we use a combination of multivariate matching and instrumental variable approaches. Using our empirical results to calibrate a simulation model, we find that proactively transferring the most severe patients could reduce mortality rates and lengthsof-stay without increasing other adverse events; however, proactive transfers should be used judiciously as being too aggressive could increase ICU congestion and degrade quality of care.

Using Machine Learning to Predict ICU Transfer in Hospitalized COVID-19 Patients

“…Given the sensitivity of the model, it can effectively identify patients who are likely to be transferred to ICU within 24 h, reducing the chance of missing the patients in need of ICU care. Moreover, clinical implementation of the tool can increase the rates of early ICU transfers, which can potentially translate into reduced mortality and shorter lengths of ICU stay [ 40 , 41 ], with favorable consequences on other complications affecting patient outcomes, such as delirium and sleep disorders [ 42 , 43 ]. However, its positive predictive value and precision are limited, and it is not practical to perform labor-intensive interventions for all patients whom the model predicted are at high risk.…”

Analysis of Benefit of Intensive Care Unit Transfer for Deteriorating Ward Patients

“…The IV was ICU bed availability, defined as the sum of physically empty ICU beds plus those with ICU patients ready for discharge. 20 , 21 , 25 , 26 This measure has been previously used as an IV for patient admission or transfer. 20 , 21 , 25 , 26 Following these studies, we assumed that spare ICU capacity encouraged transfer but did not otherwise affect the mortality of patients assessed.…”

Stronger Instruments and Refined Covariate Balance in an Observational Study of the Effectiveness of Prompt Admission to Intensive Care Units

“…Previous studies have reported that ICU admission is associated with higher mortality, but these studies are likely to have provided biased estimates, as patients who are promptly admitted to the ICU tend to have a more severe casemix, according to both measured and unmeasured patient characteristics (Chalfin et al, 2007;Gabler et al, 2013;Renaud et al, 2009). To address this problem, other investigators have used an IV to study the effects of critical care (Hu et al, 2018;Kc and Terwiesch, 2012;Shmueli et al, 2004;Valley et al, 2015;Pirracchio et al, 2011). An IV acts as a nudge or encouragement for treatment receipt that can affect the outcome only via the treatment.…”