Marga Hoogendoorn

100 the satisfaction of nurses about workload. As the Nursing Activity Score and the NASA- TLX questionnaire already contain many items to be scored we opted for the simple one-dimensional question to avoid adding more registration load. This question was unambiguous in asking for the satisfaction rate on the nursing workload during the last shift and it simply used a scale between zero and ten that nurses are used to in all kinds of daily life varying from school grades as well as review rates of consumer products and travel services. Although our study is one of the larger studies in adult ICUs comparing workload data with both the Nursing Activities Score and the NASA-TLX, the number of observations is still relatively low and this might cause lack of power to prove an association between workload satisfaction and Nursing Activities Score or NASA-TLX, especially on the subscales of NASA-TLX. To generalize the results of our study a larger study population and studies in different ICUs and in different countries are needed. It seems to be important to focus on a further validation of the optimal Nursing Activities Score per nurse. CONCLUS I ON We showed that both the objective nursing workload as measured with Nursing Activities Score and the perceived nursing workload as measured with the NASA-TLX are associated with the satisfaction with nursing workload. A Nursing Activities Score per nurse between 74 and 84 points per nurse and a total NASA-TLX of > 27 points are significantly associated with a higher workload satisfaction. This indicates that there is an optimum in the nursing workload. Further research is needed to validate the optimum Nursing Activities Score per nurse.