Variable tidal volumes improve lung protective ventilation strategies in experimental lung injury.
BACKGROUND
Noisy ventilation with variable Vt may improve respiratory function in acute lung injury.


OBJECTIVE
To determine the impact of noisy ventilation on respiratory function and its biological effects on lung parenchyma compared with conventional protective mechanical ventilation strategies.


METHODS
In a porcine surfactant depletion model of lung injury, we randomly combined noisy ventilation with the ARDS Network protocol or the open lung approach (n = 9 per group).


RESULTS
Respiratory mechanics, gas exchange, and distribution of pulmonary blood flow were measured at intervals over a 6-hour period. Postmortem, lung tissue was analyzed to determine histological damage, mechanical stress, and inflammation. We found that, at comparable minute ventilation, noisy ventilation (1) improved arterial oxygenation and reduced mean inspiratory peak airway pressure and elastance of the respiratory system compared with the ARDS Network protocol and the open lung approach, (2) redistributed pulmonary blood flow to caudal zones compared with the ARDS Network protocol and to peripheral ones compared with the open lung approach, (3) reduced histological damage in comparison to both protective ventilation strategies, and (4) did not increase lung inflammation or mechanical stress.


CONCLUSIONS
Noisy ventilation with variable Vt and fixed respiratory frequency improves respiratory function and reduces histological damage compared with standard protective ventilation strategies.
Spieth
Peter M
PM
Department of Anesthesiology and Intensive Care Therapy, University Hospital Dresden, Fetscherstrasse 74, 01307 Dresden, Germany.
Carvalho
Alysson R
AR
Pelosi
Paolo
P
Hoehn
Catharina
C
Meissner
Christoph
C
Kasper
Michael
M
Hübler
Matthias
M
von Neindorff
Matthias
M
Dassow
Constanze
C
Barrenschee
Martina
M
Uhlig
Stefan
S
Koch
Thea
T
de Abreu
Marcelo Gama
MG
D055371:Acute Lung Injury / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D000818:Animals; D004195:Disease Models, Animal; D006439:Hemodynamics; D008168:Lung / Q000098:blood supply; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption / Q000502:physiology; D010313:Partial Pressure; D011650:Pulmonary Alveoli / Q000473:pathology; D011659:Pulmonary Gas Exchange / Q000502:physiology; D011897:Random Allocation; D012121:Respiration, Artificial / Q000009:adverse effects / Q000379:methods*; D012128:Respiratory Distress Syndrome / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D015656:Respiratory Mechanics / Q000502:physiology; D018709:Statistics, Nonparametric; D013552:Swine; D013990:Tidal Volume / Q000502:physiology
D010100:Oxygen