Patient Mortality Is Associated With Staff Resources and Workload in the ICU: A Multicenter Observational Study.

OBJECTIVE: Matching healthcare staff resources to patient needs in the ICU is a key factor for quality of care. We aimed to assess the impact of the staffing-to-patient ratio and workload on ICU mortality. DESIGN: We performed a multicenter longitudinal study using routinely collected hospital data. SETTING: Information pertaining to every patient in eight ICUs from four university hospitals from January to December 2013 was analyzed. PATIENTS: A total of 5,718 inpatient stays were included. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We used a shift-by-shift varying measure of the patient-to-caregiver ratio in combination with workload to establish their relationships with ICU mortality over time, excluding patients with decision to forego life-sustaining therapy. Using a multilevel Poisson regression, we quantified ICU mortality-relative risk, adjusted for patient turnover, severity, and staffing levels. The risk of death was increased by 3.5 (95% CI, 1.3-9.1) when the patient-to-nurse ratio was greater than 2.5, and it was increased by 2.0 (95% CI, 1.3-3.2) when the patient-to-physician ratio exceeded 14. The highest ratios occurred more frequently during the weekend for nurse staffing and during the night for physicians (p < 0.001). High patient turnover (adjusted relative risk, 5.6 [2.0-15.0]) and the volume of life-sustaining procedures performed by staff (adjusted relative risk, 5.9 [4.3-7.9]) were also associated with increased mortality. CONCLUSIONS: This study proposes evidence-based thresholds for patient-to-caregiver ratios, above which patient safety may be endangered in the ICU. Real-time monitoring of staffing levels and workload is feasible for adjusting caregivers' resources to patients' needs.

Bedside assessment of passive leg raising effects on venous return.

OBJECTIVE: Passive leg raising (PLR) provides a reversible fluid-loading challenge and can be used to predict fluid responsiveness. The amount of blood volume recruited by this maneuver called stressed volume (Vs) is unknown. The present study aims to assess the quantitative effects of passive leg raising on venous return at bedside. METHODS: We conducted a prospective interventional study. Nine mechanically ventilated postoperative cardiac surgery patients with preserved left ventricular function were enrolled. Cardiac output (CO) was continuously monitored by PiCCO™ via the pulse contour method. Ten second intervals of inspiratory breath holding at four plateau pressures (5, 15, 25 and 35 cm H(2)O) were performed to measure the relationship between blood flow (CO) and central venous pressure (CVP). These were used to determine mean systemic filling pressure (Pmsf) and Vs. Patients were studied at three successive steps: semirecumbent position, after PLR and back in the semirecumbent position after volume expansion (VE). RESULTS: Similar to VE, PLR significantly increased Pmsf from 19.7 (17.0-22.6) mmHg at baseline to 22.0 (18.5-27.8) mmHg (p <0.05). CO increased 11.1% (9.5-20) with PLR and 14.8% (4.2-19.9) with VE. Venous return resistance was unchanged throughout the three conditions, whereas the the pressure gradient for venous return (Pmsf-CVP) increased during PLR (p = 0.058) and during VE (p < 0.05). Baseline circulatory compliance was 1.14 (0.52-2.65) ml mm Hg(-1) kg(-1). Vs increased to 3.5 (1.1-3.9) ml kg(-1) with PLR. CONCLUSIONS: The effect of transient hemodynamic changes on venous return induced by passive leg raising can be directly measured in intensive care patients using inspiratory-hold procedures. This technique makes quantification of PLR feasible and could be used clinically to assess fluid responsiveness.