Lung perfusion during cardiac surgery with cardiopulmonary bypass: is it necessary?

Abstract

Thirty-two pigs were randomized into group I (aortic cross clamping, antegrade cardioplegia, moderate hypothermia) and group II (normothermia, beating empty heart). Groups were subdivided into subgroups A, B and C, receiving no lung perfusion, perfusion with arterial blood and perfusion with venous blood. Swan-Ganz catheter was used to take mean pulmonary artery pressure which would be used as lung perfusion pressure. Cardiopulmonary bypass (CPB) was established through cannulating aorta and double venae cavae, mechanical ventilation was interrupted and lung perfusion was carried out for 30 min. Blood samples and pulmonary specimens were withdrawn pre- and postoperatively for gasometrical, histological and genic analyses. Postoperative comparison revealed that pulmonary vascular resistance was lower in IC than IA (P=0.01) and it was lower in IIC than IIA (P=0.005). Subgroup IIB had increasing venous oxygen tension (P=0.01) as well as arterial and venous oxygen saturation (P=0.01) compared to IIA. Arterial oxygen saturation was decreased in IIC vs. IIA (P=0.006). Histological differences were observed between subgroups A and B as well as A and C (P=0.003). Lung perfusion during CPB may improve pulmonary hemodynamic performance, optimize gas exchange and maintain cellular integrity.

Perioperative ventilatory strategies in cardiac surgery

“…The authors found that in this cohort of patients managed with low levels of PEEP (4 [2. [2][3][4][5], median ), the utilization of low tidal volumes (below 8 ml/kg of predicted body weight) were associated with increased mortality. This suggests that low PEEP levels should not be associated with low tidal volumes….…”

“…Several mechanisms are potentially involved and include ischemia-reperfusion phenomena, ventilation disorders or overload-related lung injury due to transfusion or early respiratory mechanics impairment (1)(2)(3)(4). Systemic inflammation due to ECC and aggressive high tidal volume ventilation can cause non-cardiogenic pulmonary edema or other organ failure (5)(6)(7).…”

“…To be effectively contained, ischemia-reperfusion lesions necessitate no disruption in pulmonary artery blood flow, which can be achieved with specific ECC methods but further complicates the proceeding (3,4). Conversely, adequate ventilatory strategies could prevent from various lung injuries to appear, such as atelectasis, which lead to intra-pulmonary shunt and are the leading cause of postoperative hypoxemia (5).…”

Perfusão da artéria pulmonar não melhora os índices de fator natriurético cerebral (BNP) em estudo experimental em suínos

“…Gabriel et al [19] demonstrated experimentally the advantages of the pulmonary trunk with controlled perfusion pressure using both arterial and venous blood. From the hemodynamic point of view, these authors observed a significant reduction in mean pulmonary artery pressure and pulmonary vascular resistance in the immediate postoperative period in animals that underwent perfusion controlled of the pulmonary trunk.…”

Principles of Pulmonary Protection in Heart Surgery

“…Techniques and principles of controlled lung perfusion are analyzed, based on recent research devised by Gabriel at al. 1 This section provides original discussions on extracorporeal circuit pathways for lung perfusion, how to determine lung perfusion pressure, lung perfusion using arterial and venous blood, and impact of controlled lung perfusion from hemodynamic, gasometric, inflammatory, and radiologic standpoint of view during heart surgery with CPB.…”