High Positive End-Expiratory Pressure Renders Spontaneous Effort Noninjurious

Author(s):Show less -

Morais, Caio C. A. ^[1] ; Koyama, Yukiko ^[2] ; Yoshida, Takeshi ^{[2, 3]} ; Plens, Glauco M. ^[1] ; Gomes, Susimeire ^[1] ; Lima, Cristhiano A. S. ^[1] ; Ramos, Ozires P. S. ^[1] ; Pereira, Sergio M. ^[1] ; Kawaguchi, Naomasa ^[4] ; Yamamoto, Hirofumi ^[4] ; Uchiyama, Akinori ^[2] ; Borges, Joao B. ^[5] ; Melo, Marcos F. Vidal ^[6] ; Tucci, Mauro R. ^[1] ; Amato, Marcelo B. P. ^[1] ; Kavanagh, Brian P. ^[3] ; Costa, Eduardo L. V. ^[1] ; Fujino, Yuji ^[2]

Affiliation

^[1] Univ Sao Paulo, Fac Med, Hosp Clin, Div Pneumol, Inst Coracao Incor, Sao Paulo - Brazil

^[2] Osaka Univ Hosp, Intens Care Unit, Suita, Osaka - Japan

^[3] Univ Toronto, Hosp Sick Children, Dept Crit Care Med & Anesthesia, Translat Med, 686 Bay St, Toronto, ON M5G 0A4 - Canada

^[4] Osaka Univ, Sch Allied Hlth Sci, Dept Pathol, Grad Sch Med, Suita, Osaka - Japan

^[5] Uppsala Univ, Sect Anesthesiol & Crit Care, Dept Surg Sci, Hedenstierna Lab, Uppsala - Sweden

^[6] Harvard Univ, Massachusetts Gen Hosp, Dept Anesthesia Crit Care & Pain Med, Boston, MA - USA

• Document type: Journal article
• Source: American Journal of Respiratory and Critical Care Medicine; v. 197, n. 10, p. 1285-1296, MAY 15 2018.
• Web of Science Citations: 31

Abstract

Rationale: In acute respiratory distress syndrome (ARDS), atelectatic solid-like lung tissue impairs transmission of negative swings in pleural pressure (Ppl) that result from diaphragmatic contraction. The localization of more negative Ppl proportionally increases dependent lung stretch by drawing gas either from other lung regions (e.g., nondependent lung {[}pendelluft]) or from the ventilator. Lowering the level of spontaneous effort and/or converting solid-like to fluid-like lung might render spontaneous effort noninjurious. Objectives: To determine whether spontaneous effort increases dependent lung injury, and whether such injury would be reduced by recruiting atelectatic solid-like lung with positive end-expiratory pressure (PEEP). Methods: Established models of severe ARDS (rabbit, pig) were used. Regional histology (rabbit), inflammation (positron emission tomography; pig), regional inspiratory Ppl (intrabronchial balloon manometry), and stretch (electrical impedance tomography; pig) were measured. Respiratory drive was evaluated in 11 patients with ARDS. Measurements and Main Results: Although injury during muscle paralysis was predominantly in nondependent and middle lung regions at low (vs. high) PEEP, strong inspiratory effort increased injury (indicated by positron emission tomography and histology) in dependent lung. Stronger effort (vs. muscle paralysis) caused local overstretch and greater tidal recruitment in dependent lung, where more negative Ppl was localized and greater stretch was generated. In contrast, high PEEP minimized lung injury by more uniformly distributing negative Ppl, and lowering the magnitude of spontaneous effort (i.e., deflection in esophageal pressure observed in rabbits, pigs, and patients). Conclusions: Strong effort increased dependent lung injury, where higher local lung stress and stretch was generated; effort-dependent lung injury was minimized by high PEEP in severe ARDS, which may offset need for paralysis. (AU)

• FAPESP's process: 14/02030-7 - Spontaneous breathing during mechanical ventilation in an experimental model of acute lung injury: assessment of lung inflammation by PET-CT using two values of positive end-expiratory pressure (PEEP)
• Grantee: Eduardo Leite Vieira Costa
• Support Opportunities: Regular Research Grants