High accuracy of the nine equivalents of nursing manpower use score assessed by critical care nurses

A Perren,M Previsdomini,I Perren,P Merlani

doi:10.4414/smw.2012.13555

Abstract

The nine equivalents of nursing manpower use score (NEMS) is frequently used to quantify, evaluate and allocate nursing workload at intensive care unit level. In Switzerland it has also become a key component in defining the degree of ICU hospital reimbursement. The accuracy of nurse registered NEMS scores in real life was assessed and error-prone variables were identified. In this retrospective multicentre audit three reviewers (1 nurse, 2 intensivists) independently reassessed a total of 529NEMS scores. Correlation and agreement of the sum-scores and of the different variables among reviewers, as well as between nurses and the reviewers' reference value, were assessed (ICC, % agreement and kappa). Bland & Altman (reference value - nurses) of sum-scores and regression of the difference were determined and a logistic regression model identifying risk factors for erroneous assessments was calculated. Agreement for sum-scores among reviewers was almost perfect (mean ICC = 0.99 / significant correlation p <0.0001). The nurse registered NEMS score (mean ± SD) was 24.8 ± 8.6 points versus 24.0 ± 8.6 points (p <0.13 for difference) of the reference value, with a slightly lower ICC (0.83). The lowest agreement was found in intravenous medication (0.85). Bland & Altman was 0.84 ± 10, with a significant regression between the difference and the reference value, indicating overall an overestimation of lower scores (≤29 points) and underestimation of higher scores. Accuracy of scores or variables was not associated with nurses' characteristics. In real life, nurse registered NEMS scores are highly accurate. Lower (≤29 points) NEMS sum-scores are overestimated and higher underestimated. Accuracy of scores or variables was not associated with nurses' characteristics.

Highlights

Adequate nurse staffing is a prerogative for good quality of care for both the general ward [1] and the intensive care unit (ICU) [2]
In Switzerland it has become a key component in defining the degree of ICU hospital reimbursement
Accuracy and reliability of NEMS has been poorly studied, with the exception of a formal analysis of data accuracy in the original publication [8]. These results refer to a well defined study setting with trained observers, and to the best of our knowledge no study has so far assessed the accuracy of nurse registered NEMS scores in real life

Summary

Introduction

Adequate nurse staffing is a prerogative for good quality of care for both the general ward [1] and the intensive care unit (ICU) [2]. The nine equivalents of nursing manpower use score (NEMS) [8] derives from a simplified form of the therapeutic intervention scoring system (TISS-28) [7] and is frequently used for management purposes and multicentre ICU studies These workload indicators have become, in addition to the simplified acute physiology score II (SAPS II) [9], a key component in defining the degree of hospital reimbursement in Germany [10]. Accuracy and reliability of NEMS has been poorly studied, with the exception of a formal analysis of data accuracy in the original publication [8] These results refer to a well defined study setting with trained observers, and to the best of our knowledge no study has so far assessed the accuracy of nurse registered NEMS scores in real life. The aim of our study was 1) to assess the accuracy of nurse registered NEMS scores in real life, 2) to recognise error-

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