title: Prevalence and severity of neurologic dysfunction in critically ill patients. Influence on need for continued mechanical ventilation.
abstract: OBJECTIVE
  The relative importance of neurologic dysfunction in critically ill mechanically ventilated patients has not been well studied. This study investigates the prevalence of neurologic dysfunction in critically ill mechanically ventilated patients and its influence on preventing the discontinuation of mechanical ventilation and patient outcome.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  University-based, tertiary care center.
  
  
  METHODS
  All eligible adult patients mechanically ventilated for more than 48 h were included. A total of 66 patients were evaluated.
  
  
  METHODS
  None.
  
  
  METHODS
  Two independent questionnaires, one completed by the critical care attending physician documenting the major clinical factors necessitating continued mechanical ventilation, and a second questionnaire, completed by a critical-care trained neurologist documenting neurologic status and objective cardiopulmonary status formed the basis for outcome measurements. Respiratory and physiologic data, the patient's clinical conditions, and outcome (mortality) were also included in the database.
  
  
  RESULTS
  Pulmonary factors were the major reason for prolonged ventilation in only 51 percent of the patient evaluations. Neurologic status was the major factor necessitating continued mechanical ventilation in 32 percent of the patient evaluations and a significant contributing factor in an additional 41 percent. Of the neurologic factors, diminished level of consciousness was the major cause of continued ventilatory support. This was usually due to a systemic illness, rather than a primary central nervous system disorder. Mortality was significantly lower in patients who continued to require mechanical ventilation after 48 h because of neurologic factors as opposed to pulmonary factors (15 percent vs 72 percent, p = 0.002).
  
  
  CONCLUSIONS
  There is a high prevalence of neurologic dysfunction in critically ill patients and this problem plays a significant role in preventing the discontinuation of mechanical ventilation. Altered mental status is a major factor necessitating continued mechanical ventilation in combined medical-surgical intensive care units.
authors.affiliation: Department of Medicine, University of California, San Francisco 94143-0130.
authors.forename: B J
authors.initials: BJ
authors.lastname: Kelly
authors.forename: M A
authors.initials: MA
authors.lastname: Matthay
mesh_terms: D002493:Central Nervous System Diseases / Q000628:therapy*; D016638:Critical Illness; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012121:Respiration, Artificial; D012131:Respiratory Insufficiency / Q000628:therapy; D015300:Ventilator Weaning