title: Subjective perceptions and physiological variables during weaning from mechanical ventilation.
abstract: BACKGROUND
  As costs related to mechanical ventilation increase, clear indicators of patients' readiness to be weaned are needed. Research has not yet yielded a consensus on physiological variables that are consistent correlates of weaning outcomes. Subjective perceptions rarely have been examined for their contribution to successful weaning.
  
  
  OBJECTIVE
  To explore the subjective perceptions of dyspnea, fatigue, and self-efficacy and selected physiological variables in patients being weaned from mechanical ventilation.
  
  
  METHODS
  Data were collected prospectively on 68 patients being weaned from mechanical ventilation. Subjective perceptions were measured by using 3 visual analog scales; physiological variables were measured by using the Burns Weaning Assessment Program and a patient profile. Weaning outcomes were recorded 24 hours after data collection.
  
  
  RESULTS
  Participants were primarily white women and required mechanical ventilation for a mean of less than 4 days. Participants reported mild dyspnea, moderate fatigue, and high weaning self-efficacy. High PaO2, low PaCO2, stable hemodynamic status, adequate cough and swallow reflexes, no metabolic changes, and no abdominal problems were associated with complete weaning (P = .05). Subjective perceptions were associated with physiological variables but not with weaning outcomes.
  
  
  CONCLUSIONS
  Multidimensional assessment of both primary and secondary indicators of readiness to be weaned is necessary for timely, efficient weaning from mechanical ventilation. Primary assessments include physiological variables related to gas exchange, hemodynamic status, diaphragmatic expansion, and airway clearance. Secondary assessments include perceptions related to key physiological variables. Additional research is needed to determine the predictive value of physiological variables and perceptions of dyspnea, fatigue, and self-efficacy.
authors.affiliation: School of Nursing, Ball State University, Critical Care Division, Ball Memorial Hospital, Muncie, Ind., USA.
authors.forename: Renee
authors.initials: R
authors.lastname: Twibell
authors.forename: Debra
authors.initials: D
authors.lastname: Siela
authors.forename: Mahnaz
authors.initials: M
authors.lastname: Mahmoodi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D004417:Dyspnea; D005221:Fatigue; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D009730:Nursing Assessment; D011237:Predictive Value of Tests; D011446:Prospective Studies; D020377:Self Efficacy; D015300:Ventilator Weaning / Q000451:nursing