title: Unidirectional Expiratory Valve Method to Assess Maximal Inspiratory Pressure in Individuals without Artificial Airway.
abstract: BACKGROUND
  Maximal Inspiratory Pressure (MIP) is considered an effective method to estimate strength of inspiratory muscles, but still leads to false positive diagnosis. Although MIP assessment with unidirectional expiratory valve method has been used in patients undergoing mechanical ventilation, no previous studies investigated the application of this method in subjects without artificial airway.
  
  
  OBJECTIVE
  This study aimed to compare the MIP values assessed by standard method (MIPsta) and by unidirectional expiratory valve method (MIPuni) in subjects with spontaneous breathing without artificial airway. MIPuni reproducibility was also evaluated.
  
  
  METHODS
  This was a crossover design study, and 31 subjects performed MIPsta and MIPuni in a random order. MIPsta measured MIP maintaining negative pressure for at least one second after forceful expiration. MIPuni evaluated MIP using a unidirectional expiratory valve attached to a face mask and was conducted by two evaluators (A and B) at two moments (Tests 1 and 2) to determine interobserver and intraobserver reproducibility of MIP values. Intraclass correlation coefficient (ICC[2,1]) was used to determine intraobserver and interobserver reproducibility.
  
  
  RESULTS
  The mean values for MIPuni were 14.3% higher (-117.3 ± 24.8 cmH2O) than the mean values for MIPsta (-102.5 ± 23.9 cmH2O) (p<0.001). Interobserver reproducibility assessment showed very high correlation for Test 1 (ICC[2,1] = 0.91), and high correlation for Test 2 (ICC[2,1] = 0.88). The assessment of the intraobserver reproducibility showed high correlation for evaluator A (ICC[2,1] = 0.86) and evaluator B (ICC[2,1] = 0.77).
  
  
  CONCLUSIONS
  MIPuni presented higher values when compared with MIPsta and proved to be reproducible in subjects with spontaneous breathing without artificial airway.
authors.affiliation: Department of Rehabilitation, Hospital Sírio-Libanês (HSL), São Paulo, São Paulo, Brazil.
authors.forename: Samantha Torres
authors.initials: ST
authors.lastname: Grams
authors.affiliation: Department of Rehabilitation, Hospital Sírio-Libanês (HSL), São Paulo, São Paulo, Brazil.
authors.forename: Karen Yumi Mota
authors.initials: KY
authors.lastname: Kimoto
authors.affiliation: Department of Rehabilitation, Hospital Sírio-Libanês (HSL), São Paulo, São Paulo, Brazil.
authors.forename: Elen Moda de Oliveira
authors.initials: EM
authors.lastname: Azevedo
authors.affiliation: Department of Rehabilitation, Hospital Sírio-Libanês (HSL), São Paulo, São Paulo, Brazil.
authors.forename: Marina
authors.initials: M
authors.lastname: Lança
authors.affiliation: Department of Rehabilitation, Hospital Sírio-Libanês (HSL), São Paulo, São Paulo, Brazil; Department of Pulmonary Function-Núcleo Avançado de Tórax (NAT), Hospital Sírio-Libanês (HSL), São Paulo, São Paulo, Brazil.
authors.forename: André Luis Pereira de
authors.initials: AL
authors.lastname: Albuquerque
authors.affiliation: Department of Rehabilitation, Hospital Sírio-Libanês (HSL), São Paulo, São Paulo, Brazil.
authors.forename: Christina May Moran de
authors.initials: CM
authors.lastname: Brito
authors.affiliation: Department of Rehabilitation, Hospital Sírio-Libanês (HSL), São Paulo, São Paulo, Brazil.
authors.forename: Wellington Pereira
authors.initials: WP
authors.lastname: Yamaguti
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D006801:Humans; D001239:Inhalation; D008297:Male; D053580:Muscle Strength; D015588:Observer Variation; D011312:Pressure; D015203:Reproducibility of Results; D012121:Respiration, Artificial / Q000379:methods; D012129:Respiratory Function Tests; D012132:Respiratory Muscles / Q000502:physiology; D055815:Young Adult