Newly Published
Critical Care Medicine  |   September 2018
Individual Positive End-expiratory Pressure Settings Optimize Intraoperative Mechanical Ventilation and Reduce Postoperative Atelectasis
Author Notes
  • From Divisao de Anestesia, Terapia Intensiva e Dor (S.M.P., C.M.S., B.F.F.T., M.S.P., J.E.V.) and Divisao de Pneumologia, Instituto do Coracao (S.M.P., M.R.T., C.C.A.M., M.B.P.A.), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brazil; Anesthesia Department, Hospital Sírio-Libanes, Sao Paulo, Brazil (C.M.S., B.F.F.T, ); UT Southwestern Medical Center - Radiology Department, Dallas, Texas (F.U.K.); Department of Surgical Sciences and Integrated Diagnostics, IRCCS San Martino Policlinico Hospital, University of Genoa, Italy (P.P.).
  • Corresponding article on page XXX.
    Corresponding article on page XXX.×
  • Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are available in both the HTML and PDF versions of this article. Links to the digital files are provided in the HTML text of this article on the Journal’s Web site (www.anesthesiology.org).
    Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are available in both the HTML and PDF versions of this article. Links to the digital files are provided in the HTML text of this article on the Journal’s Web site (www.anesthesiology.org).×
  • Partial results were presented as a poster at ESICM Lives in Milan, Italy, October 1–5, 2016.
    Partial results were presented as a poster at ESICM Lives in Milan, Italy, October 1–5, 2016.×
  • S.M.P. and M.R.T. contributed equally to this article.
    S.M.P. and M.R.T. contributed equally to this article.×
  • Submitted for publication February 6, 2018. Accepted for publication August 9, 2018.
    Submitted for publication February 6, 2018. Accepted for publication August 9, 2018.×
  • Research Support: Support for this study was provided by The São Paulo Research Foundation – FAPESP (#2013/04059-0), São Paulo, Brazil; Brazilian Innovation Agency (FINEP); and Coordination for the Improvement of Higher Level Personnel (CAPES), Brazil. This trial is registered at https://clinicaltrials.gov/ct2/show/NCT02314845 (NCT02314845).
    Research Support: Support for this study was provided by The São Paulo Research Foundation – FAPESP (#2013/04059-0), São Paulo, Brazil; Brazilian Innovation Agency (FINEP); and Coordination for the Improvement of Higher Level Personnel (CAPES), Brazil. This trial is registered at https://clinicaltrials.gov/ct2/show/NCT02314845 (NCT02314845).×
  • Competing Interests: The authors declare no competing interests.
    Competing Interests: The authors declare no competing interests.×
  • Correspondence: Address correspondence to Dr. Tucci: Laboratório de Pneumologia LIM 09 Faculdade de Medicina da Universidade de São Paulo, Av. Doutor Arnaldo, 455 (Sala 2144, 2nd floor), São Paulo 01246-903, Brazil. mrotucci@gmail.com. Information on purchasing reprints may be found at www.anesthesiology.org or on the masthead page at the beginning of this issue. Anesthesiology’s articles are made freely accessible to all readers, for personal use only, 6 months from the cover date of the issue.
Article Information
Critical Care Medicine / Critical Care / Respiratory System / Thoracic Anesthesia
Critical Care Medicine   |   September 2018
Individual Positive End-expiratory Pressure Settings Optimize Intraoperative Mechanical Ventilation and Reduce Postoperative Atelectasis
Anesthesiology Newly Published on September 25, 2018. doi:10.1097/ALN.0000000000002435
Anesthesiology Newly Published on September 25, 2018. doi:10.1097/ALN.0000000000002435
Abstract

Editor’s Perspective:

What We Already Know about This Topic:

  • In patients with adult respiratory distress syndrome, physiologic tidal volume and positive end-expiratory pressure (PEEP) are protective

  • In patients without lung diseases undergoing mechanical ventilation under general anesthesia, optimal PEEP is unknown

What This Article Tells Us That Is New:

  • Optimal positive end-expiratory pressure (PEEP) values for patients with normal lungs and under general anesthesia vary significantly

  • Application of individualized optimal PEEP intraoperatively not only reduces driving pressure and improves respiratory compliance and oxygenation but also reduce the incidence and severity of postoperative atelectasis

Background: Intraoperative lung-protective ventilation has been recommended to reduce postoperative pulmonary complications after abdominal surgery. Although the protective role of a more physiologic tidal volume has been established, the added protection afforded by positive end-expiratory pressure (PEEP) remains uncertain. The authors hypothesized that a low fixed PEEP might not fit all patients and that an individually titrated PEEP during anesthesia might improve lung function during and after surgery.

Methods: Forty patients were studied in the operating room (20 laparoscopic and 20 open-abdominal). They underwent elective abdominal surgery and were randomized to institutional PEEP (4 cm H2O) or electrical impedance tomography–guided PEEP (applied after recruitment maneuvers and targeted at minimizing lung collapse and hyperdistension, simultaneously). Patients were extubated without changing selected PEEP or fractional inspired oxygen tension while under anesthesia and submitted to chest computed tomography after extubation. Our primary goal was to individually identify the electrical impedance tomography–guided PEEP value producing the best compromise of lung collapse and hyperdistention.

Results: Electrical impedance tomography–guided PEEP varied markedly across individuals (median, 12 cm H2O; range, 6 to 16 cm H2O; 95% CI, 10–14). Compared with PEEP of 4 cm H2O, patients randomized to the electrical impedance tomography–guided strategy had less postoperative atelectasis (6.2 ± 4.1 vs. 10.8 ± 7.1% of lung tissue mass; P = 0.017) and lower intraoperative driving pressures (mean values during surgery of 8.0 ± 1.7 vs. 11.6 ± 3.8 cm H2O; P < 0.001). The electrical impedance tomography–guided PEEP arm had higher intraoperative oxygenation (435 ± 62 vs. 266 ± 76 mmHg for laparoscopic group; P < 0.001), while presenting equivalent hemodynamics (mean arterial pressure during surgery of 80 ± 14 vs. 78 ± 15 mmHg; P = 0.821).

Conclusions: PEEP requirements vary widely among patients receiving protective tidal volumes during anesthesia for abdominal surgery. Individualized PEEP settings could reduce postoperative atelectasis (measured by computed tomography) while improving intraoperative oxygenation and driving pressures, causing minimum side effects.