title: Pressure-controlled inverse ratio ventilation using laryngeal mask airway in gynecological laparoscopy.
abstract: BACKGROUND
  It is well documented that pressure-controlled ventilation (PCV) improves oxygenation and ventilation compared to volume-controlled ventilation and reduces peak airway pressure in gynecological laparoscopy. PCV with moderately inversed inspiratory-expiratory (I: E) ratio can successfully recruit collapsed alveoli and has been proved to be beneficial in intensive care. We tested the hypothesis that altering the I: E ratio to 1.5:1 in PCV improves ventilation during gynecological laparoscopy using laryngeal mask airway (LMA).
  
  
  OBJECTIVE
  To study pressure-controlled inverse ratio ventilation (PCIRV) with I: E ratio 1.5:1 as against PCV with I: E ratio 1:2 in gynecological laparoscopy with LMA using noninvasive parameters.
  
  
  METHODS
  Intraoperative hemodynamics and side-stream spirometry recordings were noted in 20 consecutive patients undergoing major gynecological laparoscopy with LMA. Flexible LMA or LMA supreme were used depending on normal body mass index (BMI) or high BMI, respectively.
  
  
  RESULTS
  REVERSING THE I: E ratio to 1.5:1 increased the tidal volume, mean airway pressures, and dynamic lung compliance significantly, all indicating better oxygenation at comparable peak airway pressures as against PCV with I: E ratio 1:2. There was no change in the end-tidal carbon dioxide. There was no auto-positive end expiratory pressure (PEEP) or change in the hemodynamics.
  
  
  CONCLUSIONS
  REVERSAL OF I: E ratio with PCV can be beneficially used with LMA in laparoscopy.
authors.affiliation: Department of Anaesthesiology, BEAMS Hospital, Mumbai, India.
authors.forename: Manju
authors.initials: M
authors.lastname: Sinha
authors.forename: Sheetal
authors.initials: S
authors.lastname: Chiplonkar
authors.forename: Rishita
authors.initials: R
authors.lastname: Ghanshani