Use of positive end-expiratory pressure (PEEP)

PEEP is part of a lung-protection ventilation strategy that has been highly successful in preventing further lung injury in patients with existing acute lung injury. Modern anesthetic machines can be easily set-up to provide a small amount of PEEP―at least 5 cm H2O, to all patients once the ventilator is turned on. 

While the latest Cochrane review published in 20141 did not find a reduction in mortality or pneumonia in a population of undifferentiated patients, overall patients had a higher PaO2/FiO2 on postoperative day 1 and less atelectasis as demonstrated on CT scan. 

A small study in the British Journal of Anaesthesia from 2014 used lung compliance measurements in 40 patients and showed that likely more than 5 cm of PEEP is needed to prevent intratidal recruitment/de-recruitment that results in atelectasis.7 Levels of PEEP less than 5 cm H2O add no benefit, and levels above 10 cm H2O in patients without pulmonary disease may result in unacceptable hemodynamic effects. 

References

  1. Barbosa FT, Castro AA, de Sousa-Rodrigues CF. Positive end-expiratory pressure (PEEP) during anaesthesia for prevention of mortality and postoperative pulmonary complications. Cochrane Database Syst Rev. 2014 Jun 12(6):CD007922.
     
  2. PROVE Network Investigators for the Clinical Trial Network of the European Society of Anaesthesiology, Hemmes SN, Gama de Abreu M, Pelosi P, Schultz MJ. High versus low positive end-expiratory pressure during general anaesthesia for open abdominal surgery (PROVHILO trial): a multicentre randomised controlled trial. Lancet. 2014 Aug 09;384(9942):495-503.
     
  3. Severgnini P, Selmo G, Lanza C, Chiesa A, Frigerio A, Bacuzzi A, Dionigi G, et al. Protective mechanical ventilation during general anesthesia for open abdominal surgery improves postoperative pulmonary function. Anesthesiology. 2013 Jun;118(6):1307-21.
     
  4. Guldner A, Kiss T, Serpa Neto A, Hemmes SN, Canet J, Spieth PM, et al. Intraoperative protective mechanical ventilation for prevention of postoperative pulmonary complications: a comprehensive review of the role of tidal volume, positive end-expiratory pressure, and lung recruitment maneuvers. Anesthesiology. 2015 Sep;123(3):692-713.
     
  5. Serpa Neto A, Hemmes SN, Barbas CS, Beiderlinden M, Biehl M, Binnekade JM, et al. Protective versus conventional ventilation for surgery: a systematic review and individual patient data meta-analysis. Anesthesiology. 2015 Jul;123(1):66-78.
     
  6. Ferrando C, Soro M, Canet J, Unzueta MC, Suarez F, Librero J, et al. Rationale and study design for an individualized perioperative open lung ventilatory strategy (iPROVE): study protocol for a randomized controlled trial. Trials. 2015 Apr 27;16:193.
     
  7. Wirth S, Baur M, Spaeth J, Guttmann J, Schumann S. Intraoperative positive end-expiratory pressure evaluation using the intratidal compliance-volume profile. Br J Anaesth. 2015 Mar;114(3):483-90.