Effects of off-pump coronary surgery on the mechanics of the respiratory system, lung, and chest wall: Comparison with extracorporeal circulation

Abstract

Coronary bypass surgery with and without extracorporeal circulation results in dramatic impairment of respiratory system mechanics. Based on respiratory system mechanics, early extubation after coronary artery bypass grafting should be performed with caution, no matter whether the off-pump or cardiopulmonary bypass technique is used.

Mechanisms of pulmonary dysfunction after on-pump and off-pump cardiac surgery: a prospective cohort study

“…In other observational studies and randomized trials [2,11,17-21,30,31], however, authors found off-pump versus on-pump coronary artery surgery to be associated with less pulmonary complications, less oxygenation impairment, earlier extubation, shorter mechanical ventilation and less often pneumonia, but these observations also remained largely unexplained. In contrast, other authors reported no differences in lung mechanical changes, but this is controversial too [5,6,11,23,29,30]. Our results finally do not agree with the suggestion that off-pump surgery is associated with less radiographic atelectasis than on-pump surgery [32], which, otherwise, was not confirmed in other studies [11,29].…”

“…Indeed, a lung vascular injury and oedema may be associated with deteriorated gas exchange and pulmonary compliance after surgery, although this is controversial [2,3,5-7]. We do not know whether the transfusion of RBC concentrates was a marker or a mediator of severe lung vascular injury and a high PLI, as in TRALI [12,13].…”

“…Even though biocompatibility of CPB systems have improved over decades, off-pump bypass surgery has been revitalized, potentially offering less pulmonary complications as compared to on-pump surgery [16], although only few [11,17-21] of the prospective randomised clinical trials with primary or secondary pulmonary endpoints [11,17-27], including gas exchange, duration of intubation and mechanical ventilation and occurrence of pneumonia favored off-pump surgery. Non-randomized studies indicate similar [5,28,29] or better [6,23,30-32] postoperative radiography, lung compliance and gas exchange and less pulmonary complications with off-pump surgery. The mechanisms remained unclear, however, and might relate to prevention of a proinflammatory responses, lung vascular injury and atelectasis, by obviating CPB and collapse of non-ventilated lungs [7,8,30,32].…”

Re-engineering in OPCAB—A Vettath’s perspective

“…Patients with coexisting chronic obstructive airway disease derive better early clinical benefit from CABG performed without CPB compared with on-pump surgery [47], although in low-risk patients, OPCAB induces impairment of the mechanics of the respiratory system, lung and chest wall similar to on-pump CABG [48].…”

Effect of N - Acetylcysteine on Oxidative Stress in Patients Undergoing Off Pump Coronary Artery Bypass Grafting

“…19,20 But Fransen et al, 21 had observed that the acute phase response of systemic inflammation in CABG patients, which was historically been ascribed to CPB is predominantly caused by surgical procedure per se and both OPCABG and conventional CABG produces similar degrees of oxidative injury. 4,5,22 Oxidative stress results from an imbalance between local antioxidant defences and formation of reactive oxygen derived free radicals, which are generated and released by activated inflammatory cells. ROS are highly reactive and can induce lipid peroxidation (oxidation of membrane phospholipids) and the accumulation of their products including MDA, 7,16,23,24 4-hydroxy-2-nonenal, acrolein, hydroperoxides 6 and F2-isoprostanes 7,10,14 acts as an indirect measure of free radical activity.…”