Friday, September 27, 2002

This presentation is part of : Nursing Role Effectiveness Model: Conceptualizing to Theory Testing

The Impact of Nurses' Independent Role on Patient Health Outcomes

Souraya Sidani, RN, PhD, associate professor and Diane Irvine Doran, RN, PhD, associate professor. Faculty of Nursing, University of Toronto, Toronto, ON, Canada

Objectives: Increasingly, nurses are expected to demonstrate their contribution to patient outcome achievement as a basis for evaluating practice and for monitoring improvements in practice. A model was developed that describes nursing practice in relationship to the roles nurses assume in health care, and links patient and system outcomes to nurses' role functions (Irvine, Sidani, McGillis Hall, 1998). The purpose of this study was to empirically test the propositions in the Nursing Role Effectiveness model by examining the impact of nurse and unit structural variables on nurses' independent role performance, using two different methods for conceptualizing and measuring role performance. The specific objectives of the study were to examine the impact of work design, unit experience, and nurses' educational preparation on nurses' independent role performance, and to evaluate the impact of nurses' role performance on medical/surgical patients' health outcomes.

Design: A repeated-measures design was employed to collect data on patient outcomes at hospital admission and at discharge. Data were also obtained from nurses assigned to the same units to which patients were admitted.

Population, Sample, Setting, Years: The setting for the study was four acute care hospitals. The population was hospitalized adult medical and surgical patients and nurses employed a minimum of 20 hours per week on the inpatient units. Data were collected from a sample of 409 medical and surgical patients, 289 nurses, and 24 nurse managers. Data collection occurred in 1999-2000.

Variables: The nurse and unit structural variables of interest included the nurses' length of experience on the unit, the proportion of baccalaureate prepared nurses, and the care delivery model. Nurses' independent role performance was operationally defined as evidence of nursing process through the documentation of nursing interventions and the perceived effectiveness of nursing care. The patient outcome variables included functional status, symptom distress, and perceived health benefit from nursing care.

Methods: Patient's functional status was assessed at admission and discharge by a trained nurse, using the Functional Independence Measure. Cronbach's alpha was 0. 84 and 0.91 respectively. The Symptom Distress Scale was used to collect data on patient self-reported symptom status. Cronbach's alpha was 0.79 and 0.85. The Perceived Health Benefit from Nursing Care was used to collect data on patients' satisfaction with the outcomes of nursing care (Cronbach's alpha 0.87). Nurses provided data on their years of experience on the unit, and assessed the effectiveness of nursing care, using an instrument developed by Shortell and colleagues. Cronbach's alpha was 0.85. Data on nursing interventions were extracted from the patient chart by a trained nurse using a tool adapted from the Iowa Intervention Classification instrument. Percent agreement among raters based on a sample of three charts was 99%. A questionnaire was used to collect data from nurse managers about the care delivery model and the educational preparation of nursing staff. Structural equation modeling was used to test the hypothesized relationships among the nurse and unit structural variables, nurses' role performance, and patient outcome achievement. Patients' capacity for good outcomes was controlled for by including age, medical complexity, and length of stay in the structural model.

Findings: The percentage of baccalaureate prepared nurses was positively related to the documentation of nursing interventions and to the perceived effectiveness of nursing care. Length of experience on the unit was positively related to the documentation of nursing interventions but negatively related to the perceived effectiveness of nursing care. There was greater documentation of nursing interventions on units where the care delivery model was identified as team nursing. The documentation of nursing interventions was positively related to improvements in patients' functional status and symptom distress and with perceived health benefit from nursing care. The effectiveness of nursing care was associated with the patient's perceived health benefit from nursing care.

Conclusions: The study results offer empirical validation for the propositions in the Nursing Role Effectiveness model. The baccalaureate preparation of unit staff was a significant predictor of the two role performance variables. Of the two methods used to assess nurses' independent role performance, the documentation of nursing interventions was a better predictor of patient outcome achievement than the nurses' perceived role effectiveness.

Implications: The Nursing Role Effectiveness model is a useful framework for theorizing about the effect of structural variables on process and outcomes. The study advances our understanding of how to conceptualize and measure nurses' contribution to patient outcome achievement, by focusing on nursing process. The findings underscore the importance of the educational preparation of nursing staff and offer support for policy initiatives directed toward raising the educational entry requirements for nursing.

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