Critical Care Medicine  |   July 2018
Continuous Negative Abdominal Pressure Reduces Ventilator-induced Lung Injury in a Porcine Model
Author Notes
  • From the Department of Translational Medicine (T.Y., D.E., G.O., B.K., M.P., B.P.K.) and Departments of Critical Care Medicine and Anesthesia (T.Y., B.K., B.P.K.), Hospital for Sick Children, University of Toronto, Toronto, Canada; Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Canada (T.Y., B.K., N.F., L.B., B.P.K.); Division of Respirology, Department of Medicine, University Health Network and Mount Sinai Hospital, Toronto, Ontario, Canada (N.F.); Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Ontario, Canada (L.B.); and the Cardio-Pulmonary Department, Pulmonary Division, Heart Institute (Incor), University of São Paulo, Brazil (M.A.).
  • This article is featured in “This Month in Anesthesiology,” page 1A.
    This article is featured in “This Month in Anesthesiology,” page 1A.×
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    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).×
  • Submitted for publication July 27, 2017. Accepted for publication March 9, 2018.
    Submitted for publication July 27, 2017. Accepted for publication March 9, 2018.×
  • Address correspondence to Dr. Kavanagh: Department of Critical Care Medicine, Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada M5G 1X8. brian.kavanagh@utoronto.ca. 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 / Basic Science / Critical Care / Respiratory System
Critical Care Medicine   |   July 2018
Continuous Negative Abdominal Pressure Reduces Ventilator-induced Lung Injury in a Porcine Model
Anesthesiology 7 2018, Vol.129, 163-172. doi:10.1097/ALN.0000000000002236
Anesthesiology 7 2018, Vol.129, 163-172. doi:10.1097/ALN.0000000000002236
Abstract

Background: In supine patients with acute respiratory distress syndrome, the lung typically partitions into regions of dorsal atelectasis and ventral aeration (“baby lung”). Positive airway pressure is often used to recruit atelectasis, but often overinflates ventral (already aerated) regions. A novel approach to selective recruitment of dorsal atelectasis is by “continuous negative abdominal pressure.”

Methods: A randomized laboratory study was performed in anesthetized pigs. Lung injury was induced by surfactant lavage followed by 1 h of injurious mechanical ventilation. Randomization (five pigs in each group) was to positive end-expiratory pressure (PEEP) alone or PEEP with continuous negative abdominal pressure (−5 cm H2O via a plexiglass chamber enclosing hindlimbs, pelvis, and abdomen), followed by 4 h of injurious ventilation (high tidal volume, 20 ml/kg; low expiratory transpulmonary pressure, −3 cm H2O). The level of PEEP at the start was ≈7 (vs. ≈3) cm H2O in the PEEP (vs. PEEP plus continuous negative abdominal pressure) groups. Esophageal pressure, hemodynamics, and electrical impedance tomography were recorded, and injury determined by lung wet/dry weight ratio and interleukin-6 expression.

Results: All animals survived, but cardiac output was decreased in the PEEP group. Addition of continuous negative abdominal pressure to PEEP resulted in greater oxygenation (Pao2/fractional inspired oxygen 316 ± 134 vs. 80 ± 24 mmHg at 4 h, P = 0.005), compliance (14.2 ± 3.0 vs. 10.3 ± 2.2 ml/cm H2O, P = 0.049), and homogeneity of ventilation, with less pulmonary edema (≈10% less) and interleukin-6 expression (≈30% less).

Conclusions: Continuous negative abdominal pressure added to PEEP reduces ventilator-induced lung injury in a pig model compared with PEEP alone, despite targeting identical expiratory transpulmonary pressure.