title: Effects of recruitment maneuver and positive end-expiratory pressure on respiratory mechanics and transpulmonary pressure during laparoscopic surgery.
abstract: BACKGROUND
  The authors tested the hypothesis that during laparoscopic surgery, Trendelenburg position and pneumoperitoneum may worsen chest wall elastance, concomitantly decreasing transpulmonary pressure, and that a protective ventilator strategy applied after pneumoperitoneum induction, by increasing transpulmonary pressure, would result in alveolar recruitment and improvement in respiratory mechanics and gas exchange.
  
  
  METHODS
  In 29 consecutive patients, a recruiting maneuver followed by positive end-expiratory pressure 5 cm H(2)O maintained until the end of surgery was applied after pneumoperitoneum induction. Respiratory mechanics, gas exchange, blood pressure, and cardiac index were measured before (T(BSL)) and after pneumoperitoneum with zero positive end-expiratory pressure (T(preOLS)), after recruitment with positive end-expiratory pressure (T(postOLS)), and after peritoneum desufflation with positive end-expiratory pressure (T(end)).
  
  
  RESULTS
  Esophageal pressure was used for partitioning respiratory mechanics between lung and chest wall (data are mean ± SD): on T(preOLS), chest wall elastance (E(cw)) and elastance of the lung (E(L)) increased (8.2 ± 0.9 vs. 6.2 ± 1.2 cm H(2)O/L, respectively, on T(BSL); P = 0.00016; and 11.69 ± 1.68 vs. 9.61 ± 1.52 cm H(2)O/L on T(BSL); P = 0.0007). On T(postOLS), both chest wall elastance and E(L) decreased (5.2 ± 1.2 and 8.62 ± 1.03 cm H(2)O/L, respectively; P = 0.00015 vs. T(preOLS)), and Pao(2)/inspiratory oxygen fraction improved (491 ± 107 vs. 425 ± 97 on T(preOLS); P = 0.008) remaining stable thereafter. Recruited volume (the difference in lung volume for the same static airway pressure) was 194 ± 80 ml. Pplat(RS) remained stable while inspiratory transpulmonary pressure increased (11.65 + 1.37 cm H(2)O vs. 9.21 + 2.03 on T(preOLS); P = 0.007). All respiratory mechanics parameters remained stable after abdominal desufflation. Hemodynamic parameters remained stable throughout the study.
  
  
  CONCLUSIONS
  In patients submitted to laparoscopic surgery in Trendelenburg position, an open lung strategy applied after pneumoperitoneum induction increased transpulmonary pressure and led to alveolar recruitment and improvement of E(cw) and gas exchange.
authors.affiliation: Department of Anesthesia and Intensive Care, University of Foggia, Foggia, Italy. g.cinnella@unifg.it
authors.forename: Gilda
authors.initials: G
authors.lastname: Cinnella
authors.forename: Salvatore
authors.initials: S
authors.lastname: Grasso
authors.forename: Savino
authors.initials: S
authors.lastname: Spadaro
authors.forename: Michela
authors.initials: M
authors.lastname: Rauseo
authors.forename: Lucia
authors.initials: L
authors.lastname: Mirabella
authors.forename: Potito
authors.initials: P
authors.lastname: Salatto
authors.forename: Antonella
authors.initials: A
authors.lastname: De Capraris
authors.forename: Luigi
authors.initials: L
authors.lastname: Nappi
authors.forename: Pantaleo
authors.initials: P
authors.lastname: Greco
authors.forename: Michele
authors.initials: M
authors.lastname: Dambrosio
mesh_terms: D000328:Adult; D062186:Arterial Pressure; D005260:Female; D006801:Humans; D010535:Laparoscopy; D008168:Lung / Q000503:physiopathology*; D008170:Lung Compliance; D008176:Lung Volume Measurements; D008297:Male; D011028:Pneumoperitoneum, Artificial / Q000379:methods; D011175:Positive-Pressure Respiration / Q000379:methods*; D011659:Pulmonary Gas Exchange; D015656:Respiratory Mechanics; D013990:Tidal Volume