Newly Published
Critical Care Medicine  |   February 2019
Lung Recruitment in Obese Patients with Acute Respiratory Distress Syndrome
Author Notes
  • From the Department of Anesthesia, Critical Care and Pain Medicine (J.F., R.R.S.S., M.T.D., C.Z., L.B.), the Respiratory Care Department (R.M.K.), and the Department of Radiology (F.J.F., F,M.T.), Massachusetts General Hospital, Boston, Massachusetts; and the Pulmonary Division, Cardio-Pulmonary Department, Heart Institute (Incor), Hospital Das Clínicas, Faculty of Medicine, University of Sao Paulo, São Paulo, Brazil (C.C.A.M., M.B.P.A.).
  • Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
  • Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
  • Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
  • Respiratory Care Department, Massachusetts General Hospital, Boston, Massachusetts
  • Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
  • Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
  • Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
  • Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
  • Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
  • Submitted for publication May 31, 2018. Accepted for publication January 14, 2019.
    Submitted for publication May 31, 2018. Accepted for publication January 14, 2019.×
  • Preliminary data from this study was presented as an abstract presentation and oral communication at the 38th International Symposium on Intensive Care and Emergency Medicine, March 20–23, 2018, Square Brussels Meeting Center, Mont des Arts, Brussels, Belgium. J.F. and R.R.S.S. contributed equally to this article.
    Preliminary data from this study was presented as an abstract presentation and oral communication at the 38th International Symposium on Intensive Care and Emergency Medicine, March 20–23, 2018, Square Brussels Meeting Center, Mont des Arts, Brussels, Belgium. J.F. and R.R.S.S. contributed equally to this article.×
  • *Members of Massachusetts General Hospital Lung Rescue Team Investigators are listed in the appendix.
    Members of Massachusetts General Hospital Lung Rescue Team Investigators are listed in the appendix.×
  • Correspondence: Address correspondence to Dr. Berra: Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, 02114, Boston, Massachusetts. lberra@mgh.harvard.edu. 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
Critical Care Medicine   |   February 2019
Lung Recruitment in Obese Patients with Acute Respiratory Distress Syndrome
Anesthesiology Newly Published on February 28, 2019. doi:10.1097/ALN.0000000000002638
Anesthesiology Newly Published on February 28, 2019. doi:10.1097/ALN.0000000000002638
Abstract

Editor’s Perspective:

What We Already Know about This Topic:

  • Obesity increases the propensity to atelectasis in acute respiratory distress syndrome, but the optimal approach to reversing this atelectasis is uncertain

What This Article Tells Us That Is New:

  • A clinical crossover study comparing three approaches to titrate positive end-expiratory pressure (PEEP; according to a fixed table, according to end-expiratory esophageal pressure, and targeting the best compliance during a decremental PEEP trial) found that a recruitment maneuver followed by decremental PEEP minimized atelectasis and overdistension, and best restored compliance and oxygenation without causing hemodynamic impairment

Background: Obese patients are characterized by normal chest-wall elastance and high pleural pressure and have been excluded from trials assessing best strategies to set positive end-expiratory pressure (PEEP) in acute respiratory distress syndrome (ARDS). The authors hypothesized that severely obese patients with ARDS present with a high degree of lung collapse, reversible by titrated PEEP preceded by a lung recruitment maneuver.

Methods: Severely obese ARDS patients were enrolled in a physiologic crossover study evaluating the effects of three PEEP titration strategies applied in the following order: (1) PEEPARDSNET: the low PEEP/Fio2 ARDSnet table; (2) PEEPINCREMENTAL: PEEP levels set to determine a positive end-expiratory transpulmonary pressure; and (3) PEEPDECREMENTAL: PEEP levels set to determine the lowest respiratory system elastance during a decremental PEEP trial following a recruitment maneuver on respiratory mechanics, regional lung collapse, and overdistension according to electrical impedance tomography and gas exchange.

Results: Fourteen patients underwent the study procedures. At PEEPARDSNET (13 ± 1 cm H2O) end-expiratory transpulmonary pressure was negative (−5 ± 5 cm H2O), lung elastance was 27 ± 12 cm H2O/L, and PaO2/Fio2 was 194 ± 111 mmHg. Compared to PEEPARDSNET, at PEEPINCREMENTAL level (22 ± 3 cm H2O) lung volume increased (977 ± 708 ml), lung elastance decreased (23 ± 7 cm H2O/l), lung collapse decreased (18 ± 10%), and ventilation homogeneity increased thus rising oxygenation (251 ± 105 mmHg), despite higher overdistension levels (16 ± 12%), all values P < 0.05 versus PEEPARDSnet. Setting PEEP according to a PEEPDECREMENTAL trial after a recruitment maneuver (21 ± 4 cm H2O, P = 0.99 vs. PEEPINCREMENTAL) further lowered lung elastance (19 ± 6 cm H2O/l) and increased oxygenation (329 ± 82 mmHg) while reducing lung collapse (9 ± 2%) and overdistension (11 ± 2%), all values P < 0.05 versus PEEPARDSnet and PEEPINCREMENTAL. All patients were maintained on titrated PEEP levels up to 24 h without hemodynamic or ventilation related complications.

Conclusions: Among the PEEP titration strategies tested, setting PEEP according to a PEEPDECREMENTAL trial preceded by a recruitment maneuver obtained the best lung function by decreasing lung overdistension and collapse, restoring lung elastance, and oxygenation suggesting lung tissue recruitment.