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Page 8 of 12 Echeverria-Villalobos et al. Vessel Plus 2019;3:33 I http://dx.doi.org/10.20517/2574-1209.2019.12

Gagnon et al. [86] studied 40 patients undergoing CABG with CPB. Patients were randomized into two
groups, no ventilation (group I) and ventilation with low V (3 mL/kg) and ZEEP during CPB. Endothelial
T
function was assessed through the changes in pulmonary vascular resistance index (PVRI) after the
injection of acetylcholine (ACh) into the pulmonary artery. Although patients in the ventilated group had
a better vasodilatory response to ACh, the difference in PVRI between the two groups was not statistically
significant neither after declamping of the aorta (P = 0.32) nor at 1 h after CPB (P = 0.28). In addition,
LTV with or without PEEP has been associated with attenuation of the systemic and pulmonary immune-
inflammatory response and thereby, its effect in the lungs [9,10,12,87] .

MV and pulmonary perfusion during CPB
Discontinuation of the pulmonary artery circulation during CPB significantly affects the bronchial blood
flow and metabolic demand which results in ischemia-reperfusion injury. Nevertheless, maintaining
pulmonary circulation and ventilation during CPB have been associated with reduced ischemia-reperfusion
[95]
damage in preclinical models .

In humans, the impact of continuous pulmonary perfusion during extracorporeal circulation on reducing
[96]
postoperative lung injury remains controversial [96-98] . Santini et al. compared pulsatile pulmonary
perfusion during CPB with conventional CPB in patients undergoing cardiac surgery. The pulsatile
pulmonary perfusion group showed increased PaO /FiO and lung compliance with reduced neutrophils
2
2
in the bronchoalveolar lavage when compared to the conventional group. Moreover, pulmonary perfusion
has been also associated with an increased postoperative oxygenation when compared to the use of
[97]
histidine-tryptophan-ketoglutarate solution during CPB in patients undergoing cardiac surgery . Even
though pulmonary perfusion during CPB reduces the postoperative inflammatory response and improves
oxygenation, long-term benefits are yet to be determined. However, its implementation may considerably
increase surgeons’ workload.

CONCLUSION
A variety of MV strategies may have potential benefits in patients undergoing cardiac surgery with CPB.
PMV is a useful mechanistic strategy during CPB associated with reduced systemic and inflammatory
responses and thereby, lung injury. Nevertheless, the impact of these findings on postoperative morbidity
and mortality has not been clearly established. Future prospective RCTs should address the need for clinical
data describing both, short- and long-term outcomes in patients undergoing cardiac surgeries with CPB
under MV.

DECLARATIONS
Authors’ contributions
Made substantial contributions to conception and outline of this manuscript: Echeverria-Villalobos M
Made substantial contributions to data search, interpretation, and writing: Echeverria-Villalobos M,
Munlemvo DM, Fiorda-Diaz J, Essandoh MK

Availability of data and materials
Not applicable.

Financial support and sponsorship
None.

Conflicts of interest
All authors declared that there are no conflicts of interest.