Can apneic oxygen insufflation become a novel lung protective ventilation strategy? A randomized, controlled, blinded, single center clinical trial

OBJECTIVE: The aim of this study was to determine whether a AOI strategy on non-ventilated lung could reduce the regional and systemic proinflammatory cytokine and oxidative stress response associated with esophagectomy, and to evaluate whether AOI can be used as a novel lung protective ventilation strategy. Its impact on oxygenation after OLV, surfactant protein A, B, C (SP-A, B, C), postoperative hospital stay and postoperative pulmonary complications (PPCs) was also evaluated. METHODS: Fifty-four adults (ASA II-III) undergoing esophagectomy with OLV were enrolled in the study. Patients were randomly assigned into 2 groups: control group (group C) and treated group (group T). Group C was treated with traditional OLV mode,while group T was given AOI of 5 L/min oxygen on the non-ventilated lung immediately at the beginning of OLV. Arterial blood gas was analyzed before and after OLV. A bronchoalveolar lavage(BAL) was performed after OLV on the non-ventilated lung. Proinflammatory cytokine, oxidative stress markers(TNF-α, NF-κB,sICAM-1,IL-6,IL-10,SOD,MDA) and SP-A, B, C were analyzed in serum and BALF as the primary endpoint.The clinical outcome determined by PPCs was assessed as the secondary endpoint. RESULTS: Patients with AOI had better oxygenation in the recovery period, oxygenation index(OI) (394[367–426] and 478[440–497]mmHg, respectively) of group T at T(2) and T(3) were significantly higher than those (332[206–434] and 437[331–512]mmHg, respectively) of group C. OLV resulted in an increase in the measured inflammatory markers in both groups, however, the increase of inflammatory markers upon OLV in the group C was significantly higher than those of group T. OLV resulted in an increase in the measured SP-A, B, C in serum of both groups. However, the levels of SP-A, B, C of group T were lower than those of group C in serum after OLV, and the results in BALF were the opposite. The BALF levels of SOD(23.88[14.70–33.93]U/ml) of group T were higher than those(15.99[10.33–24.16] U/ml) of group C, while the levels of MDA in both serum and BALF of group T(8.60[4.14–9.85] and 1.88[1.33–3.08]nmol/ml, respectively) were all lower than those of group C (11.10[6.57–13.75] and 1.280[1.01–1.83]nmol/ml) after OLV. There was no statistical difference between the two groups in terms of postoperative hospital stay and the incidence of PPCs. CONCLUSION: AOI on non-ventilated lung during OLV can improve the oxygenation function after OLV, relieve the inflammatory and oxidative stress response in the systemic and non-ventilated lung after OLV associated with esophagectomy. TRIAL REGISTRATION: ChiCTR-IOR-17011037. Registered on 31 March 2017.