2012 National Meeting

3051 — Associations between Timing of Intensive Care Unit Admission, Nursing Factors, and Patient Outcomes

Li Y, and He J, Clinical and Operational Analytics, OIA; Sales AE, VA Inpatient Evalution Center, OIA; Almenoff P, Clinical and Operational Analytics, OIA;

Previous research suggests a negative relationship between nurse staffing and adverse patient outcomes. The relationship depends in part on whether a patient has an ICU stay during hospitalization. However, ICU patients may be direct admissions or transferred from medical/surgical wards. Timing of ICU admission may have substantial impact on patient outcomes. This study examines if the likelihood of experiencing preventable complications and 30-day mortality vary by nurse staffing level and across 3 stratums of patients stratified by the timing of ICU admission.

This cross-sectional study included 269,799 admissions to 445 acute care units at 125 VA medical centers in FY2008. Data were from VA administrative datasets, DSS Discharge, Ward, and ALB extracts, Vista extracts of laboratory results, and national databases on market/health service area characteristics. We stratified patients into 3 groups using timing of ICU admission: ward only, ICU first, and ward-to-ICU transfer. Nursing factors included total nursing hours per patient day (HPPD) and the proportion of registered nurse (RN) hours to total nursing hours (skill mix). We conducted hierarchical logistic regression models separately for medical and surgical patients and two dependent variables: experienced preventable complications and 30-day mortality. We regressed the dependent variables on patient, unit, facility, and market characteristics, adjusting for clustering at the unit and facility levels.

Overall complication and mortality rates were 4.4% and 5.0% for medical patients, compared to 4.5% and 2.0% for surgical patients. Ward-to-ICU transfers accounted for 4.1% of medical patients and 16.6% of surgical patients. HPPD and RN skill mix were 16.0 and 90.8% for ICU first patients, compared to 9.4 and 56.8% for the other two strata. Multivariable analysis results suggested that, compared to ward-to-ICU transfers, ward only and ICU first patients were less likely to experience complications (OR = 0.24 for ward only and OR = 0.47 for ICU first, p <.001) and had lower 30-day mortality (OR = 0.23 for ward only and OR = 0.34 for ICU first, p <.001) among medical admissions. For surgical admissions, ward only patients but not ICU first patients were less likely to experience complications (OR = 0.27, p <.001) and had lower 30-day mortality (OR = 0.33, p <.001) than ward-to-ICU transfers. RN skill mix was negatively associated with 30-day mortality (OR = 0.988, p <.01) and had a borderline negative association with experiencing complication (OR = 0.994, p = .053) only among surgical admissions.

Ward-to-ICU transfers account for only a small proportion of hospital admissions but are more likely to experience adverse outcomes. The association of patient outcomes with timing of ICU admission and nurse staffing level differ for medical vs. surgical admissions.

Identifying determinants of delayed ICU transfer is critical in improving current practices in triaging patients to direct ICU admission.