title: Perioperative noninvasive ventilation in obese patients: a qualitative review and meta-analysis.
abstract: BACKGROUND
  Perioperative noninvasive ventilation (NIV) has been proposed to reduce postoperative morbidity and improve perioperative outcomes in patients undergoing general anesthesia. Whether it is advantageous to apply NIV just before and after general anesthesia in obese patients has not been yet established.
  
  
  OBJECTIVE
  To perform a qualitative review and meta-analysis to assess the effectiveness and tolerability of perioperative NIV in obese patients.
  
  
  METHODS
  All studies in English language performed in clinical setting that compared the application of NIV with standard care just before and after induction of general anesthesia in obese adults (body mass index [BMI]≥35 kg/m(2)) were included. Data on oxygenation, respiratory function, complications, and outcomes were extracted.
  
  
  RESULTS
  Twenty-nine articles were selected and used in the qualitative review. Eleven studies including 768 patients were used for subsequent meta-analyses. Compared with standard preoxygenation, NIV was associated with a significant improvement in oxygenation (P<.0001) before tracheal intubation. Benefits in oxygenation (P<.0001), clearance of carbon dioxide (P<.0001), and pulmonary function testing (P<.0001) after general anesthesia were observed with NIV compared with standard care. Postoperatively, NIV was associated with a decreased risk of respiratory complications (relative risk [RR] = .33; 95% confidence interval [CI] .16-.66; P = .002), but not of reintubation after tracheal extubation (RR = .41; 95% CI .09-1.82]; P = .3657) and unplanned intensive care unit admission (RR = .43; 95% CI .16-1.15; P = .0937). NIV-related complications in obese patients were mainly due to intolerance and ranged from 7% to 28% of cases. NIV-related anastomotic leakage and adverse events were not reported.
  
  
  CONCLUSIONS
  Results from this review and meta-analysis suggest that NIV is well tolerated and effective in improving perioperative care in obese patients. The application of NIV before and after general anesthesia should be considered and promoted in relevant cases.
authors.affiliation: Department of Medicine, Anesthesiology and Intensive Care, University of Padova, Padova, Italy. Electronic address: michele.carron@unipd.it.
authors.forename: Michele
authors.initials: M
authors.lastname: Carron
authors.affiliation: Department of Medicine, Anesthesiology and Intensive Care, University of Padova, Padova, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Zarantonello
authors.affiliation: Department of Cardiac, Thoracic and Vascular Sciences, Biostatistics, Epidemiology and Public Health Unit, University of Padova, Padova, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Tellaroli
authors.affiliation: Department of Medicine, Anesthesiology and Intensive Care, University of Padova, Padova, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Ori
mesh_terms: D000758:Anesthesia / Q000379:methods; D050110:Bariatric Surgery / Q000009:adverse effects / Q000379:methods*; D006801:Humans; D007430:Intraoperative Care / Q000379:methods; D063087:Noninvasive Ventilation; D009767:Obesity, Morbid / Q000503:physiopathology / Q000601:surgery*; D010366:Peak Expiratory Flow Rate / Q000502:physiology; D011183:Postoperative Complications / Q000209:etiology; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012120:Respiration Disorders / Q000209:etiology / Q000503:physiopathology; D016896:Treatment Outcome
keywords: Anesthesia; Bariatric surgery; Complications; Gas exchange; Lung function; Noninvasive ventilation; Obesity