title: Efficacy of ventilator waveforms observation in detecting patient-ventilator asynchrony.
abstract: OBJECTIVE
  The value of visual inspection of ventilator waveforms in detecting patient-ventilator asynchronies in the intensive care unit has never been systematically evaluated. This study aims to assess intensive care unit physicians' ability to identify patient-ventilator asynchronies through ventilator waveforms.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  Intensive care unit of a University Hospital.
  
  
  METHODS
  Twenty-four patients receiving mechanical ventilation for acute respiratory failure.
  
  
  METHODS
  Forty-three 5-min reports displaying flow-time and airway pressure-time tracings were evaluated by 10 expert and 10 nonexpert, i.e., residents, intensive care unit physicians. The asynchronies identified by experts and nonexperts were compared with those ascertained by three independent examiners who evaluated the same reports displaying, additionally, tracings of diaphragm electrical activity.
  
  
  RESULTS
  Data were examined according to both breath-by-breath analysis and overall report analysis. Sensitivity, specificity, and positive and negative predictive values were determined. Sensitivity and positive predictive value were very low with breath-by-breath analysis (22% and 32%, respectively) and fairly increased with report analysis (55% and 44%, respectively). Conversely, specificity and negative predictive value were high with breath-by-breath analysis (91% and 86%, respectively) and slightly lower with report analysis (76% and 82%, respectively). Sensitivity was significantly higher for experts than for nonexperts for breath-by-breath analysis (28% vs. 16%, p < .05), but not for report analysis (63% vs. 46%, p = .15). The prevalence of asynchronies increased at higher ventilator assistance and tidal volumes (p < .001 for both), whereas it decreased at higher respiratory rates and diaphragm electrical activity (p < .001 for both). At higher prevalence, sensitivity decreased significantly (p < .001).
  
  
  CONCLUSIONS
  The ability of intensive care unit physicians to recognize patient-ventilator asynchronies was overall quite low and decreased at higher prevalence; expertise significantly increased sensitivity for breath-by-breath analysis, whereas it only produced a trend toward improvement for report analysis.
authors.affiliation: Dipartimento di Medicina Clinica e Sperimentale, Università del Piemonte Orientale Amedeo Avogadro, Alessandria, Novara, Vercelli, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Colombo
authors.forename: Gianmaria
authors.initials: G
authors.lastname: Cammarota
authors.forename: Moreno
authors.initials: M
authors.lastname: Alemani
authors.forename: Luca
authors.initials: L
authors.lastname: Carenzo
authors.forename: Federico Lorenzo
authors.initials: FL
authors.lastname: Barra
authors.forename: Rosanna
authors.initials: R
authors.lastname: Vaschetto
authors.forename: Arthur S
authors.initials: AS
authors.lastname: Slutsky
authors.forename: Francesco
authors.initials: F
authors.lastname: Della Corte
authors.forename: Paolo
authors.initials: P
authors.lastname: Navalesi
mesh_terms: D006785:Hospitals, University; D006801:Humans; D007362:Intensive Care Units; D015588:Observer Variation; D010820:Physicians; D011446:Prospective Studies; D012119:Respiration; D012121:Respiration, Artificial / Q000379:methods*