Lung injury after cardiopulmonary bypass: Alternative treatment prospects

Introduction: Lung dysfunction following cardiac surgery is currently viewed as the consequence of atelectasis and lung injury. While the mechanism of atelectasis has been largely detailed, the pathogenesis of lung injury after cardiopulmonary bypass is still unclear. Based upon clinical and experimental studies, we hypothesized that lungs could be injured through a mechanical phenomenon. Methods: We recorded pulmonary compliance at six key moments of a heart operation in 62 adult patients undergoing elective cardiac surgery. We focused on the period lasting from anesthetic induction to aorta unclamping. We calculated the variation of static and dynamic pulmonary compliance caused by thorax opening; ΔCstat1 and ΔCdyn1 and that caused by cardiopulmonary bypass, ΔCstat2 and ΔCdyn2. Blood gases were performed under standardized ventilation after anesthetic induction and after surgical closure. The PaO2/FiO2 ratio was calculated. ∆PaO2/FiO2 was the criterion for lung dysfunction. We compared ΔCstat1 and ΔCdyn1 with both ∆PaO2/FiO2 and, respectively, ΔCstat2 and ΔCdyn2. Results: Static and dynamic compliance increased with the opening of the thorax and decreased with the start of cardiopulmonary bypass. The PaO2/FiO2 ratio diminished after surgery. ΔCstat1 and ΔCdyn1 were negatively correlated with both ∆PaO2/FiO2 (r=-0.42; p<0.001 and r=-0.44; p<0.001) and, respectively, with ΔCstat2 and ΔCdyn2 (r=-0.59; p<0.001 and r=-0.53; p<0.001). Conclusions: Increased pulmonary compliance induced by the opening of the thorax is correlated with worsened intrapulmonary shunt after cardiopulmonary bypass. A mechanical phenomenon could be partly responsible for post-operative hypoxemia.

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The N-terminal lectin-like domain of thrombomodulin reduces acute lung injury without anticoagulant effects in a rat cardiopulmonary bypass model

General Thoracic and Cardiovascular Surgery ◽

10.1007/s11748-020-01292-8 ◽

2020 ◽

Vol 68 (8) ◽

pp. 785-792

Author(s):

Tatsuya Itonaga ◽

Shingo Hirao ◽

Kazuhiro Yamazaki ◽

Tadashi Ikeda ◽

Kenji Minatoya ◽

...

Keyword(s):

Acute Lung Injury ◽

Cardiopulmonary Bypass ◽

Lung Injury

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A rise of MMP-2 and MMP-9 in bronchoalveolar lavage fluid is associated with acute lung injury after cardiopulmonary bypass in a swine model

Perfusion ◽

10.1191/0267659103pf662oa ◽

2003 ◽

Vol 18 (2) ◽

pp. 107-113 ◽

Cited By ~ 12

Author(s):

Wolfgang Eichler ◽

J F Matthias Bechtel ◽

Jan Schumacher ◽

Johanna A Wermelt ◽

Karl-Friedrich Klotz ◽

...

Keyword(s):

Acute Lung Injury ◽

Cardiopulmonary Bypass ◽

Lung Injury ◽

Bronchoalveolar Lavage ◽

Bronchoalveolar Lavage Fluid ◽

Lavage Fluid ◽

Swine Model ◽

Tissue Samples ◽

Pulmonary Capillary ◽

A Prospective Study

Postoperative acute lung injury (ALI) contributes to the morbidity and mortality following cardiopulmonary bypass (CPB). To determine whether the presence of matrix metalloproteinases (MMPs) is associated with ALI after CPB, MMP-2 and MMP-9 activities in bronchoalveolar lavage fluid (BALF) were compared with parameters indicating impaired gas exchange. In a prospective study, 17 minipigs were subjected to CPB for 60 min. Before and at five and 180 min after CPB, MMP-2 and MMP-9 were assayed in BALF and the arterial-alveolar gradient of oxygen tension (AaDO2), the pulmonary capillary wedge pressure (PCWP) and the water content of lung tissue samples (Wt) were evaluated and compared with baseline values. MMP-2 and MMP-9 increased significantly 5 minutes (2.1- and 6.2-fold, respectively) and 180 minutes (3.4- and 14.3-fold, respectively) post-CPB. AaDO2 and Wt, but not PCWP, increased significantly 180 minutes after CPB and only AaDO2, but not PCWP or Wt, was significantly correlated with MMP-2 (r/0.66, p/0.006) and MMP-9 (r/0.62, p/0.01). In conclusion, high levels of MMP-2 and MMP-9 in the pulmonary compartment are associated with ALI after CPB.

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