[Effects of the lung protective ventilatory strategy on proinflammatory cytokine release during one-lung ventilation]

A prolonged period of one-lung ventilation(OLV) is required during thoracic surgery and this may activate cytokine release and cause lung inflammatory response. The lung protective ventilatory strategy has reduced lung and systemic cytokine release and achieved remarkable curative effect in patients with acute respiratory distress syndrome (ARDS). This study was to investigate the effect of the lung protective ventilatory strategy on proinflammatory cytokine release during OLV in patients underwent thoracic surgery.

Forty patients underwent esophagectomy were randomly divided into conventional ventilation (CV) group (n=20) and protective ventilation (PV) group (n=20). In CV group, all patients received two-lung ventilation (TLV) and OLV with a tidal volume (VT) of 10 mL/kg and an inspiration/expiration ratio (I/E) of 1:1.5. In PV group, all patients received TLV with a VT of 10 mL/kg and an I/E ratio of 1:1.5, and received OLV with a VT of 5-6 mL/kg and an I/E ratio of 1:1, along with positive end-expiratory pressure (PEEP) preset at 3-5 cm H2O. Blood samples of 3 mL were extracted at three time courses, which were after tracheal intubation (T1), 120 min after OLV (T2) and 24 h after operation (T3), to analyze concentrations of interleukin (IL)-6 and IL-8 in the two groups. Values of airway peak pressure (Ppeak), airway plateau pressure (Pplat), and airway resistance(Raw)were also recorded using side stream spirometry.

In CV group, concentrations of IL-6 and IL-8 at T2 [(269.4+/-57.2) ng/L, (180.8+/-35.0) ng/L] and T3[(335.8+/-98.7) ng/L,(178.5+/-18.3) ng/L] were significantly increased as compared with those at T1 [(17.0+/-5.4) ng/L,(18.2+/-2.8) ng/L](P<0.05). In PV group, concentrations of IL-6 and IL-8 at T2 [(209.3+/-55.7) ng/L], (115.3+/-71.5) ng/L] and T3 [(278.2+/-100.8) ng/L,(124.2+/-40.1) ng/L] were significantly increased as compared with those at T1[(20.0+/-7.1) ng/L,(15.3+/-3.6) ng/L] (P<0.05). Concentrations of IL-6 and IL-8 at T2 and T3 were significantly higher in CV group than in PV group (P<0.05). Ppeak, Pplat and Raw at T2 were significantly higher in CV group [(33.6+/-4.6 cmH2O,(21.5+/-3.1) cmH2O, (26.3+/-2.1) cmH2O.L(-1).S(-1)] than in PV group [(26.7+/-3.5) cmH2O, (12.4+/-2.1) cmH2O, (18.3+/-2.3) cmH2O.L(-1).S(-1)](P<0.05).

Concentrations of IL-6 and IL-8 are increased during and after OLV in thoracic surgery. The lung protective ventilatory strategy can reduce the airway pressure and airway resistance during OLV, decrease the release of IL-6 and IL-8, and inhibit lung inflammatory responses during OLV and postoperatively.