The impact of the nursing hours per patient day (NHPPD) staffing method on patient outcomes: a retrospective analysis of patient and staffing data.

BACKGROUND In March 2002 the Australian Industrial Relations Commission ordered the introduction of a new staffing method - nursing hours per patient day (NHPPD) - for implementation in Western Australia public hospitals. This method used a "bottom up" approach to classify each hospital ward into one of seven categories using characteristics such as patient complexity, intervention levels, the presence of high dependency beds, the emergency/elective patient mix and patient turnover. Once classified, NHPPD were allocated for each ward. OBJECTIVES The objective of this study was to determine the impact of implementing the NHPPD staffing method on 14 nursing-sensitive outcomes: central nervous system complications, wound infections, pulmonary failure, urinary tract infection, pressure ulcer, pneumonia, deep vein thrombosis, ulcer/gastritis/upper gastrointestinal bleed, sepsis, physiologic/metabolic derangement, shock/cardiac arrest, mortality, failure to rescue and length of stay. DESIGN AND SETTING The research design was an interrupted time series using retrospective analysis of patient and staffing administrative data from three adult tertiary hospitals in metropolitan Perth over a 4-year period. SAMPLE All patient records (N=236,454) and nurse staffing records (N=150,925) from NHPPD wards were included. RESULTS The study found significant decreases in the rates of nine nursing-sensitive outcomes when examining hospital-level data following implementation of NHPPD; mortality, central nervous system complications, pressure ulcers, deep vein thrombosis, sepsis, ulcer/gastritis/upper gastrointestinal bleed shock/cardiac arrest, pneumonia and average length of stay. At the ward level, significant decreases in the rates of five nursing-sensitive outcomes; mortality, shock/cardiac arrest, ulcer/gastritis/upper gastrointestinal bleed, length of stay and urinary tract infections occurred. CONCLUSIONS The findings provide evidence to support the continuation of the NHPPD staffing method. They also add to evidence about the importance of nurse staffing to patient safety; evidence that must influence policy. This study is one of the first to empirically review a specific nurse staffing method, based on an individual assessment of each ward to determine staffing requirements, rather than a "one-size-fits-all" approach.