title: Sleep disturbances in patients admitted to a step-down unit after ICU discharge: the role of mechanical ventilation.
abstract: BACKGROUND
  Severe sleep disruption is a well-documented problem in mechanically ventilated, critically ill patients during their time in the intensive care unit (ICU), but little attention has been paid to the period when these patients become clinically stable and are transferred to a step-down unit (SDU). We monitored the 24-h sleep pattern in 2 groups of patients, one on mechanical ventilation and the other breathing spontaneously, admitted to our SDU to assess the presence of sleep abnormalities and their association with mechanical ventilation.
  
  
  METHODS
  Twenty-two patients admitted to an SDU underwent 24-h polysomnography with monitoring of noise and light.
  
  
  RESULTS
  One patient did not complete the study. At night, 10 patients showed reduced sleep efficiency, 6 had reduced percentage of REM sleep, and 3 had reduced percentage of slow wave sleep (SWS). Sleep amount and quality did not differ between patients breathing spontaneously and those on mechanical ventilation. Clinical severity (SAPS(II) score) was significantly correlated with daytime total sleep time and efficiency (r = 0.51 and 0.5, P < 0.05, respectively); higher pH was correlated with reduced sleep quantity and quality; and higher PaO(2) was correlated with increased SWS (r = 0.49; P = 0.02).
  
  
  CONCLUSIONS
  Patients admitted to an SDU after discharge from an ICU still have a wide range of sleep abnormalities. These abnormalities are mainly associated with a high severity score and alkalosis. Mechanical ventilation does not appear to be a primary cause of sleep impairment.
authors.affiliation: Sleep Center, Istituto Scientifico di Pavia and Montescano, Fondazione S. Maugeri, IRCCS, Pavia, Italy. francesco.fanfulla@fsm.it
authors.forename: Francesco
authors.initials: F
authors.lastname: Fanfulla
authors.forename: Piero
authors.initials: P
authors.lastname: Ceriana
authors.forename: Nadia
authors.initials: N
authors.lastname: D'Artavilla Lupo
authors.forename: Rossella
authors.initials: R
authors.lastname: Trentin
authors.forename: Francesco
authors.initials: F
authors.lastname: Frigerio
authors.forename: Stefano
authors.initials: S
authors.lastname: Nava
mesh_terms: D000368:Aged; D000472:Alkalosis, Respiratory / Q000150:complications / Q000209:etiology; D001143:Arousal; D020920:Dyssomnias; D006801:Humans; D007362:Intensive Care Units / Q000706:statistics & numerical data; D010351:Patient Discharge / Q000706:statistics & numerical data; D017286:Polysomnography; D012121:Respiration, Artificial / Q000009:adverse effects*; D012720:Severity of Illness Index; D012890:Sleep / Q000502:physiology; D012893:Sleep Wake Disorders / Q000453:epidemiology / Q000209:etiology*