title: Preoperative maximal expiratory pressure is associated with duration of invasive mechanical ventilation after cardiac surgery: An observational study.
abstract: OBJECTIVE
  To evaluate the association of maximal expiratory pressure (MEP), maximal inspiratory pressure (MIP), and peak expiratory flow (PEF) with total duration of invasive mechanical ventilation (IMV) in subjects undergoing cardiac surgery.
  
  
  BACKGROUND
  Prolonged IMV is associated with respiratory infections, prolonged hospitalization, and increased mortality. Pulmonary function tests can help predict postoperative outcomes after cardiac surgery.
  
  
  METHODS
  We recruited subjects admitted for cardiac surgery. All MIP, MEP, and PEF measurements were performed before surgery. Multivariable analysis was performed using a multiple linear regression model to control for possible confounders and test for association of MIP, MEP, and PEF with IMV duration.
  
  
  RESULTS
  Overall, 125 subjects were included in the study. Higher MEP was associated with reduced duration of IMV after adjustment for confounders (P = 0.015), but no such association was observed between MIP or PEF and IMV.
  
  
  CONCLUSIONS
  In subjects undergoing elective cardiac surgery, preoperative MEP is associated with IMV duration.
authors.affiliation: Federal University of Rio Grande do Sul, Hospital de Clínicas de Porto Alegre, Brazil. Electronic address: mauricezanini@gmail.com.
authors.forename: Maurice
authors.initials: M
authors.lastname: Zanini
authors.affiliation: Physical Medicine and Rehabilitation Division, Hospital de Clínicas de Porto Alegre, Brazil.
authors.forename: Rosane Maria
authors.initials: RM
authors.lastname: Nery
authors.affiliation: Federal University of Rio Grande do Sul, Brazil.
authors.forename: Raquel Petry
authors.initials: RP
authors.lastname: Buhler
authors.affiliation: Federal University of Rio Grande do Sul, Hospital de Clínicas de Porto Alegre, Brazil.
authors.forename: Juliana Beust
authors.initials: JB
authors.lastname: de Lima
authors.affiliation: Department of Medicine, Federal University of Rio Grande do Sul, Brazil.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Stein
mesh_terms: D006348:Cardiac Surgical Procedures; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D000072277:Maximal Respiratory Pressures / Q000379:methods*; D008875:Middle Aged; D011184:Postoperative Period; D057234:Preoperative Period; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000379:methods*; D013997:Time Factors
keywords: Coronary artery bypass grafting; Heart valve replacement; Mechanical ventilation; Respiratory function; Respiratory pressure