Nursing Activities Score (NAS): 5 years of experience in the intensive care units of an Italian University hospital.

Objective: To retrospectively analyse the application of the Nursing Activities Score (NAS) in an intensive care department from January 2006 to December 2011.

Method: The sample consists of 5856 patients in three intensive care units (GICU: General Intensive Care Unit, NeuroICU: Neurosurgical Intensive Care Unit, CICU: Cardiothoracic Intensive Care Unit) of an Italian University hospital. The NAS was calculated for each patient every 24 hours.