In 1994, sponsored by the European Communities Commission and the FRICE (Foundation for Research on Intensive Care in Europe), the EURICUS proyect was born, which, among other objectives, sets out to know objectively the work loads of the nursing staff in the intensive medicine services. As a consequence, the FRICE developed and validated a new therapeutic index, the nine equivalents of nursing manpower use score, NEMS. This scale (NEMS) can determine the therapeutic effort required by critically ill patients in a simple way and only using nine therapeutic variables. The objectives of this study are: to know if the NEMS scale reflects the therapeutic effort of the pediatric critical patients and validate if the NEMS scale measures the health care effect of the nursing staff in a pediatric intensive care unit (PICU). The study was performed in the Pediatrics Intensive Care Unit of the Hospital Sant Joan de Déu in Barcelona. The population studied was made up by the patients admitted to the PICU during a three week period (January 17 to February 6, 2001). Eight nurses from the unit having different shifts participated in the data collection. The NEMS scale was measured at 7 am.m. and 7 p.m. respectively in all the patients and then a qualitative assessment of the data obtained was performed. During this period, there were 50 admissions in the unit: 2.2 admissiions per day. The occupancy rate during the days of the study was 75%. A total of 389 measurements were performed, obtaining a mean value of 26.1 on the NEMS scale. Principal contributions of the nurses participating in the study were:They believe that use of the health care effort scales is useful in the intensive care units. The NEMS scale is easy to use and requires little time to be filled out. The NEMS scale reflects the therapeutic effort of the pediatric critically ill patients, but does not reflect the nursing staff cares. In a pediatric ICU, the age of the patient who is hospitalized influences the requirements of the nursing staff. Depending on at what time the scale is measured, not all the nursing activity is reflected, due to the high number of daily admissions and discharges. The NEMS scale is simple to use and reflects the therapeutic effort of the patients admitted to a PICU; however it only measures those cares delegated from therapeutic intervention and does not reflect the basic nursing cares.