Effect of remote ischemic preconditioning on exhaled nitric oxide concentration in piglets during and after one-lung ventilation

Abstract

BackgroundRemote ischemic preconditioning (RIP) may protect target organs from ischemia – reperfusion injury, however, little is known on pulmonary effects of RIP prior to, immediately after and several hours after one-lung ventilation (OLV). The present randomized, controlled, animal experiment was undertaken to analyze these issues. MethodsAfter animal ethics committee approval, twelve piglets (26 ± 2 kg) were anesthetized and randomly assigned to a control (n = 6) or to a RIP group (n = 6). For RIP, arterial perfusion of a hind limb was suspended by an inflated blood pressure cuff (200 mmHg for 5 min) and deflated for another 5 min, this was repeated four times. After intubation, mechanical ventilation (MV) was kept constant with tidal volume 10 ml/kg, inspired oxygen fraction (FIO2) 0.40, and positive end-expiratory pressure (PEEP) 5cmH2O. FIO2 was increased to 1 after RIP in the RIP group and after the sham procedure in the control group, respectively, for the time of OLV. OLV was established by left-sided bronchial blockade. After OLV, TLV was re-established until the end of the protocol. Exhaled nitric oxide (NO) was measured by ozon chemiluminiscense and ventilatory and hemodynamic variables were assessed according to the protocol. ResultsHemodynamic and respiratory data were similar in both groups. Arterial pO2 was higher in the RIP group after two hours of OLV. In the control group, exhaled NO decreased during OLV and remained at low levels for the rest of the protocol. In the RIP group, exhaled NO decreased as well during OLV but returned to baseline levels when TLV was re-established. ConclusionsRIP has no effects on hemodynamic and respiratory variables in juvenile, healthy piglets. RIP improves the oxygenation after OLV and prevents the decline of exhaled NO after OLV.