Partial liquid ventilation and positive end-expiratory pressure reduce ventilator-induced lung injury in an ovine model of acute respiratory failure.
OBJECTIVE
To examine the isolated and combined effects of positive end-expiratory pressure (PEEP) and partial liquid ventilation (PLV) on the development of ventilator-induced lung injury in an ovine model.


METHODS
Prospective controlled animal study.


METHODS
University-based cardiovascular animal physiology laboratory.


METHODS
Thirty-eight anesthetized supine sheep weighing 22.3 +/- 2.2 kg.


METHODS
Animals were ventilated for 6 hrs (respiratory rate, 15; FIO2, 1.0, inspiratory/expiratory ratio, 1:1) with one of five pressure-controlled strategies, expressed as peak inspiratory pressure (PIP)/PEEP: low-PIP, 25/5 cm H2O (n = 8); high-PIP, 50/5 cm H2O (n = 8); high-PIP-PLV, 50/5 cm H2O-PLV (n = 8); high-PEEP, 50/20 cm H2O (n = 7); and high-PEEP-PLV, 50/20 cm H2O-PLV (n = 7).


RESULTS
Compared with the low-PIP control, high-PIP ventilation increased airleak, shunt, histologic evidence of lung injury, neutrophil infiltrates, and wet lung weight. Maintaining PEEP at 20 cm H2O or adding PLV reduced the development of physiologic shunt and dependent histologic injury indexes. Neither higher PEEP nor PLV reduced the high incidence of barotrauma observed in high-PIP animals.


CONCLUSIONS
We conclude that application of PLV or PEEP at 20 cm H2O may improve gas exchange and afford lung protection from ventilator-induced lung injury during high-pressure mechanical ventilation in this model.
Reickert
Craig A
CA
Department of Surgery, University of Michigan Medical Center, Ann Arbor, USA.
Rich
Preston B
PB
Crotti
Stefania
S
Mahler
Simon A
SA
Awad
Samir S
SS
Lynch
William R
WR
Johnson
Kent J
KJ
Hirschl
Ronald B
RB
D000208:Acute Disease; D000818:Animals; D004195:Disease Models, Animal; D021061:Liquid Ventilation; D008168:Lung / Q000473:pathology / Q000503:physiopathology*; D011175:Positive-Pressure Respiration; D012131:Respiratory Insufficiency / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D012756:Sheep; D012122:Ventilators, Mechanical / Q000009:adverse effects*