Effects of Dexmedetomidine Infusion on Inflammatory Responses and Injury of Lung Tidal Volume Changes during One-Lung Ventilation in Thoracoscopic Surgery: A Randomized Controlled Trial

Abstract

One-lung ventilation in thoracic surgery provokes profound systemic inflammatory responses and injury related to lung tidal volume changes. We hypothesized that the highly selective a2-adrenergic agonist dexmedetomidine attenuates these injurious responses. Sixty patients were randomly assigned to receive dexmedetomidine or saline during thoracoscopic surgery. There is a trend of less postoperative medical complication including that no patients in the dexmedetomidine group developed postoperative medical complications, whereas four patients in the saline group did (0% versus 13.3%, p = 0.1124). Plasma inflammatory and injurious biomarkers between the baseline and after resumption of two-lung ventilation were particularly notable. The plasma high-mobility group box 1 level decreased significantly from 51.7 (58.1) to 33.9 (45.0) ng.ml^-1 (p < 0.05) in the dexmedetomidine group, which was not observed in the saline group. Plasma monocyte chemoattractant protein 1 [151.8 (115.1) to 235.2 (186.9) pg.ml^-1, p < 0.05] and neutrophil elastase [350.8 (154.5) to 421.9 (106.1) ng.ml^-1, p < 0.05] increased significantly only in the saline group. In addition, plasma interleukin-6 was higher in the saline group than in the dexmedetomidine group at postoperative day 1 [118.8 (68.8) versus 78.5 (58.8) pg.ml^-1, p = 0.0271]. We conclude that dexmedetomidine attenuates one-lung ventilation-associated inflammatory and injurious responses by inhibiting alveolar neutrophil recruitment in thoracoscopic surgery.

Figure 1

CONSORT diagram.

Figure 2

Changes in perioperative plasma levels of one-lung ventilation-induced inflammatory biomarkers. (a). Perioperative changes in plasma high-mobility group box 1 protein levels. ^∗ indicates a higher level in the DEX group than in the saline group with a p < 0.05 at T₁. # indicates an intragroup increase between T₁ and T₂ with p < 0.05 in the DEX group. (b). Perioperative changes in plasma monocyte chemoattractant protein 1 levels. # indicates an intragroup increase between T₁ and T₂ with p < 0.05 in the saline group. (c). Perioperative changes in plasma interleukin-6 levels. ^∗ indicates a higher level in the saline group than in the DEX group with p < 0.05 at T₃. # indicates intragroup increases between T₁ and T₂ with p < 0.05 in both DEX and saline groups.

Figure 3

Changes in perioperative plasma levels of one-lung ventilation-induced lung tidal volume injury biomarkers. (a). Perioperative changes in plasma neutrophil elastase levels. # indicates an intragroup increase between T₁ and T₂ with p < 0.05 in the saline group. (b). Perioperative changes in plasma Clara cell protein levels. # indicates intragroup increases between T₁ and T₂ with p < 0.05 in both DEX and saline groups.