Objective:To assess the effect of a 12-hour shift on mood states and sleepiness at the beginning and end of the shift. Method: Quantitative, cross-sectional and descriptive study. It was conducted with 70 neonatal intensive care unit nurses. The Brunel Mood Scale (BRUMS), Karolinska Sleepiness Scale (KSS), and a socio-demographic profile questionnaire were administered. Results: When the KSS and BRUMS scores were compared at the beginning of the shift associations were found with previous sleep quality (p ≤ 0.01), and quality of life (p ≤ 0.05). Statistical significant effects on BRUMS scores were also associated with previous sleep quality, quality of life, liquid ingestion, healthy diet, marital status, and shift work stress. When the beginning and end of the shift were compared, different KSS scores were seen in the group of all nurses and in the night shift one. Significant vigor and fatigue scores were observed within shift groups. Conclusion: A good night's sleep has positive effects on the individual`s mood states both at the beginning and the end of the shift. The self-perception of a good quality of life also positively influenced KSS and BRUMS scores at the beginning and end of the shift. Proper liquid ingestion led to better KSS and BRUMS scores.
DESCRIPTORS
INTRODUCTIONIntensive care unit (ICU) nurses have to provide high quality care for fragile patients (1) . Such care occurs in a technology-rich and rapidly changing environment, which gives rise to both human and nonhuman sources of error (2) . Workers with high demands have significantly enhanced risks of developing psychiatric disorders, with stress and fatigue as important contributing factors. Both acute fatigue and chronic fatigue negatively affect quality of life and performance (2) . Stress is a complex phenomenon that includes the psychophysiological stress event and its perception, intrinsic and extrinsic mediating factors, and the response (3) . It has been suggested that perceptions of stress in work situations are more influential than the stressors themselves. Stress can affect the physical health of nurses, manifesting as headaches, skin rashes, intestinal disorders and weight variations. Ultimately, and importantly, it affects the quality of patient care. Care of children with poor prognoses, workload, distrust of nurses' opinions by physicians, lack of knowledge and the limited experience of staff are possible stressors (4) . In addition, lack of support and respect within a team, long hours of work and the responsibility of taking care of critically ill patients, can be added to the list of stressors (5) . ICU nurses must also deal with the patients' family members (3) . Intensive care unit nurses usually work shifts; according to a number of studies 12-h shifts are associated with difficulty in staying awake, sleep deprivation and a threefold risk of making mistakes (6)(7) . A number of studies have quantified the negative impact of sleep deprivation on shift work, fatigue, performance and learning (8) .Comparisons betw...