title: Echocardiographic evaluation during weaning from mechanical ventilation.
abstract: BACKGROUND
  Echocardiographic, electrocardiographic and other cardiorespiratory variables can change during weaning from mechanical ventilation.
  
  
  OBJECTIVE
  To analyze changes in cardiac function, using Doppler echocardiogram, in critical patients during weaning from mechanical ventilation, using two different weaning methods: pressure support ventilation and T-tube; and comparing patient subgroups: success vs. failure in weaning.
  
  
  METHODS
  Randomized crossover clinical trial including patients under mechanical ventilation for more than 48 h and considered ready for weaning. Cardiorespiratory variables, oxygenation, electrocardiogram and Doppler echocardiogram findings were analyzed at baseline and after 30 min in pressure support ventilation and T-tube. Pressure support ventilation vs. T-tube and weaning success vs. failure were compared using ANOVA and Student's t-test. The level of significance was p<0.05.
  
  
  RESULTS
  Twenty-four adult patients were evaluated. Seven patients failed at the first weaning attempt. No echocardiographic or electrocardiographic differences were observed between pressure support ventilation and T-tube. Weaning failure patients presented increases in left atrium, intraventricular septum thickness, posterior wall thickness and diameter of left ventricle and shorter isovolumetric relaxation time. Successfully weaned patients had higher levels of oxygenation.
  
  
  CONCLUSIONS
  No differences were observed between Doppler echocardiographic variables and electrocardiographic and other cardiorespiratory variables during pressure support ventilation and T-tube. However cardiac structures were smaller, isovolumetric relaxation time was larger, and oxygenation level was greater in successfully weaned patients.
authors: Intensive Care Unit, Hospital de Caridade Dr. Astrogildo de Azevedo, Santa Maria, RS, Brazil. luciele@terra.com.br
authors: Luciele Medianeira
authors: LM
authors: Schifelbain
authors: Silvia Regina Rios
authors: SR
authors: Vieira
authors: Janete Salles
authors: JS
authors: Brauner
authors: Deise Mota
authors: DM
authors: Pacheco
authors: Alexandre Antonio
authors: AA
authors: Naujorks
mesh_terms: D018806:APACHE; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D015150:Echocardiography, Doppler; D005260:Female; D006321:Heart / Q000502:physiology*; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D011312:Pressure; D012121:Respiration, Artificial; D013997:Time Factors; D015300:Ventilator Weaning / Q000379:methods*; D055815:Young Adult