Sleep as one of the basic human needs is absolutely essential for patients to survive from critical illness. Despite the best medical interventions, critically ill patients require sleep to recuperate. Therefore, sleep quality and factors that might negatively influence sleep were assessed. The current study revealed that critically ill patients perceived sleep quality as altered and described this alteration as a moderate degree of sleep disturbance. The etiologies of sleep disturbances in the current study were found to be multifactorial: presence of strange and bad odors, noise, having...