The effects of methylene blue on ovine post‐pneumonectomy pulmonary oedema

Abstract

MB did not reduce PPO and accumulation of NOx in sheep subjected to ventilation with excessive tidal volumes and ZEEP.

Inhibitor of neuronal nitric oxide synthase improves gas exchange in ventilator-induced lung injury after pneumonectomy

“…The present study confirms our previous findings in sheep: pneumonectomy followed by one-lung ventilation with excessive tidal volumes and zero end-expiratory pressure promotes lung injury, as characterized by increased pulmonary vascular pressure and permeability, and accumulation of extravascular lung water in concert with derangements of gas exchange [4,12]. Continuous infusion of the inhibitor of nNOS, 7-nitroindazole (NI), from two hours after the start of injurious ventilation dampened the decrease in oxygenation and the respiratory acidosis.…”

“…The absence of changes in PBVI in the early postpneumonectomy period confirmed our previous finding that ovine ventilator-induced lung injury after pneumonectomy is not a result of cardiac failure or fluid volume overload [4,12]. This notion is also supported by the observation of no significant differences in GEDVI, which is another marker of preload, between injuriously and protectively ventilated animals [19].…”

“…The introducer was also used for infusion of Ringer’s acetate at a rate of 10 ml/kg/h throughout the experiment. Additionally, a 4 F fiberoptic thermistor catheter (PV PV2024L, Pulsion Medical Systems) was placed in the descending thoracic aorta via an introducer in a femoral artery, and a right-sided pneumonectomy was performed, as previously reported [4,12]. …”

“…Systemic vascular resistance index (SVRI) and pulmonary vascular resistance index (PVRI) were calculated by the Cold Z-021. All the thermodilution variables were computed as a mean of three measurements, as previously described from our laboratory [4,12]. …”

“…The cytotoxic effect of NO, most likely, increases after combining with highly reactive oxygen species to form peroxynitrite, which supposedly plays an important role in the pathogenesis of MODS [5]. In a previous study, we found that infusion of methylene blue, an unspecific inhibitor of eNOS and iNOS, did not attenuate the emergence of ovine PPE [12]. This motivated us to a search for other inhibitors of NOS that could potentially protect against VILI.…”