Intensive Care Medicine

, Volume 35, Issue 5, pp 781–795 | Cite as

Sleep and delirium in ICU patients: a review of mechanisms and manifestations

  • Milagros I. Figueroa-RamosEmail author
  • Carmen Mabel Arroyo-Novoa
  • Kathryn A. Lee
  • Geraldine Padilla
  • Kathleen A. Puntillo


Sleep deprivation and delirium are conditions commonly encountered in intensive care unit patients. Sleep in these patients is characterized by sleep fragmentation, an increase in light sleep, and a decrease of both slow wave sleep and rapid eye movement sleep. The most common types of delirium in this population are hypoactive and mixed-type. Knowledge about the mechanisms of sleep and delirium has evolved over time, but these phenomena are not yet well understood. What is known, however, is that different areas in the brainstem transmit information to the thalamus and cortex necessary for sleep–wake regulation. Delirium is related to an imbalance in the synthesis, release, and inactivation of some neurotransmitters, particularly acetylcholine and dopamine. The relationship between sleep deprivation and delirium has been studied for many years and has been viewed as reciprocal. The link between them may be ascribed to shared mechanisms. An imbalance in neurotransmitters as well as alteration of melatonin production may contribute to the pathogenesis of both phenomena. A better understanding of the mechanisms and factors that contribute to sleep deprivation and delirium can guide the development of new methods and models for prevention and treatment of these problems and consequently improve patient outcomes.


Sleep Sleep deprivation Delirium Intensive care unit Mechanisms 



We thank Dr. Richard S. Bourne for his review of a prior rendition of this manuscript.


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Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Milagros I. Figueroa-Ramos
    • 1
    • 2
    Email author
  • Carmen Mabel Arroyo-Novoa
    • 1
    • 2
  • Kathryn A. Lee
    • 2
  • Geraldine Padilla
    • 2
  • Kathleen A. Puntillo
    • 2
  1. 1.School of NursingUniversity of Puerto Rico, Medical Sciences CampusSan JuanPuerto Rico
  2. 2.School of NursingUniversity of California, San FranciscoSan FranciscoUSA

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