Effect of remote ischemic preconditioning combined with dexmedetomidine on lung injury during one-lung ventilation in patients undergoing thoracic surgery

Abstract

Objective To investigate the effect of remote ischemic preconditioning (RIPC) combined with dexmedetomidine on the lung injury during one-lung ventilation (OLV) in the patients undergoing thoracic surgery. Methods Eighty ASA physical status I or Ⅱ patients, scheduled for elective radical operation for esophageal cancer, were randomly divided into 2 groups(40 patients each group) using a random number table: control group and RIPC combined with dexmedetomidine group (ORD group). In ORD group, 10 min after endotraeheal intubation, RIPC was induced by 3 cycles of 5 min lower extremity ischemia followed by 5 min reperfusion, and at the same time a loading dose of dexmedetomidine 1.0 μg/kg was infused intravenously over 15 min and then dexmedetomidine was infused at a rate of 0.5 μg/(kg·h) until the end of operation. At 0, 30 min, 1 h and 2 h of OLV(T1-4), blood samples were obtained from the radial artery for blood gas analysis and determination of plasma concentrations of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-10.Oxygenation index and respiratory index were calculated. Exhaled breath condensate was collected at T1, T3 and T4, and the pH value was measured. Results The respiratory index at T2-4 in 2 groups were significantly higher than those at T1, control group: 1.16 ± 0.12, 1.02 ± 0.10 and 0.97 ± 0.12 vs. 0.49 ± 0.06, ORD group: 0.84 ± 0.15, 0.72 ± 0.12 and 0.65 ± 0.10 vs. 0.48 ± 0.08, there were statistical differences (P <0.05). The oxygenation index at T2-4 in 2 groups were significantly lower than those at T1, control group: (287.1 ± 21.8), (306.8 ± 35.2) and (312.9 ± 25.5) mmHg (1 mmHg =0.133 kPa) vs. (426.5 ± 39.0) mmHg, ORD group: (335.0 ± 34.7), (341.1 ± 41.3) and (359.1 ± 38.8) mmHg vs. (433.6 ± 23.8) mmHg, there were statistical differences (P <0.05). Compared with control group, the respiratory index at T2-4 in ORD group were elevated, the oxygenation index at T2-4 in ORD group were depressed, there were statistical differences (P <0.05). The TNF-α and IL-1β at T3-4 in 2 groups were significantly higher than those at T1, control group: (31.4 ± 6.7) and (38.3 ± 7.2) μg/L vs. (16.2 ± 5.1) μg/L, (7.2 ± 1.6) and (12.3 ± 4.2) μg/L vs. (3.0 ± 0.7) μg/L, ORD group: (21.7 ± 5.4) and (23.4 ± 5.1) μg/L vs. (16.3 ± 4.7) μg/L, (4.8 ± 0.9) and (6.3 ± 1.6) μg/L vs. (2.9 ± 0.8) μg/L, there were statistical differences (P <0.05). The pH value of exhaled breath condensate at T3-4 in 2 groups were significantly lower than those at T1, control group: 6.41 ± 0.23 and 6.33 ± 0.21 vs. 6.93 ± 0.35, ORD group: 6.79 ± 0.30 and 6.74 ± 0.33 vs. 7.07 ± 0.22, there were statistical differences (P <0.05). The IL-10 at T4 in 2 groups were significantly higher than those at T1, control group: (30.6 ± 6.3) μg/L vs. (19.2 ± 5.3) μg/L, ORD group: (41.3 ± 5.2) μg/L vs. (19.5 ± 4.9) μg/L, there were statistical differences (P <0.05). Compared with control group, the TNF-α and IL-1β at T3-4 in ORD group were depressed, the pH value of exhaled breath condensate at T3-4 in ORD group were elevated, the IL-10 at T4 in ORD group was elevated, there were statistical differences (P <0.05). Conclusions RIPC combined with dexmedetomidine can inhibit inflammatory responses and reduce airway acidification, thus attenuate the lung injury during OLV in the patients undergoing thoracic surgery. Key words: Radical resection of esophageal carcinoma; One-lung ventilation; Ischemic preconditioning; Dexmedetomidine