Biological Impact of Transpulmonary Driving Pressure in Experimental Acute Respiratory Distress Syndrome. (August 2015)

• Record Type: Journal Article
• Authors: Samary, Cynthia S.; Santos, Raquel S.; Santos, Cíntia L.; Felix, Nathane S.; Bentes, Maira; Barboza, Thiago; Capelozzi, Vera L.; Morales, Marcelo M.; Garcia, Cristiane S. N. B.; Souza, Sergio A. L.; Marini, John J.; Gama de Abreu, Marcelo; Silva, Pedro L.; Pelosi, Paolo; Rocco, Patricia R. M.
• Is Part Of: Anesthesiology. Volume 123:Number 2(2015)
• Publication Date: 2015-08
• Subjects: Anesthesiology -- Periodicals; Anesthetics -- Periodicals; Anesthesia -- Periodicals; 617.9605
• DOI: 10.1097/ALN.0000000000000716
• Languages: English
• ISSNs: 0003-3022

Abstract

<abstract> <title> <x xml:space="preserve">Abstract</x> </title> <sec> <title>Background:</title> <p>Ventilator-induced lung injury has been attributed to the interaction of several factors: tidal volume (V<sub>T</sub>), positive end-expiratory pressure (PEEP), transpulmonary driving pressure (difference between transpulmonary pressure at end-inspiration and end-expiration, ΔP, L), and respiratory system plateau pressure (Pplat, rs).</p> </sec> <sec> <title>Methods:</title> <p>Forty-eight Wistar rats received <italic>Escherichia coli</italic> lipopolysaccharide intratracheally. After 24 h, animals were randomized into combinations of V<sub>T</sub> and PEEP, yielding three different ΔP, L levels: ΔP, L<sub>LOW</sub> (V<sub>T</sub> = 6 ml/kg, PEEP = 3 cm H<sub>2</sub>O); ΔP, L<sub>MEAN</sub> (V<sub>T</sub> = 13 ml/kg, PEEP = 3 cm H<sub>2</sub>O or V<sub>T</sub> = 6 ml/kg, PEEP = 9.5 cm H<sub>2</sub>O); and ΔP, L<sub>HIGH</sub> (V<sub>T</sub> = 22 ml/kg, PEEP = 3 cm H<sub>2</sub>O or V<sub>T</sub> = 6 ml/kg, PEEP = 11 cm H<sub>2</sub>O). In other groups, at low V<sub>T</sub>, PEEP was adjusted to obtain a Pplat, rs similar to that achieved with ΔP, L<sub>MEAN</sub> and ΔP, L<sub>HIGH</sub> at high V<sub>T</sub>.</p> </sec> <sec> <title>Results:</title> <p>At ΔP, L<sub>LOW</sub>, expressions of interleukin (IL)-6, receptor for advanced glycation end products (RAGE), and amphiregulin were reduced, despite morphometric evidence of alveolar collapse. At ΔP, L<sub>HIGH</sub> (V<sub>T</sub> = 6 ml/kg and PEEP = 11 cm H<sub>2</sub>O), lungs were fully open and IL-6 and RAGE were reduced compared with ΔP, L<sub>MEAN</sub> (27.4 ± 12.9 <italic>vs.</italic> 41.6 ± 14.1 and 0.6 ± 0.2 <italic>vs.</italic> 1.4 ± 0.3, respectively), despite increased hyperinflation and amphiregulin expression. At ΔP, L<sub>MEAN</sub> (V<sub>T</sub> = 6 ml/kg and PEEP = 9.5 cm H<sub>2</sub>O), when PEEP was not high enough to keep lungs open, IL-6, RAGE, and amphiregulin expression increased compared with ΔP, L<sub>LOW</sub> (41.6 ± 14.1 <italic>vs.</italic> 9.0 ± 9.8, 1.4 ± 0.3 <italic>vs.</italic> 0.6 ± 0.2, and 6.7 ± 0.8 <italic>vs.</italic> 2.2 ± 1.0, respectively). At Pplat, rs similar to that achieved with ΔP, L<sub>MEAN</sub> and ΔP, L<sub>HIGH</sub>, higher V<sub>T</sub> and lower PEEP reduced IL-6 and RAGE expression.</p> </sec> <sec> <title>Conclusion:</title> <p>In the acute respiratory distress syndrome model used in this experiment, two strategies minimized ventilator-induced lung injury: (1) low V<sub>T</sub> and PEEP, yielding low ΔP, L and Pplat, rs; and (2) low V<sub>T</sub> associated with a PEEP level sufficient to keep the lungs open.</p> </sec> </abstract>