Protective effects of dexmedetomidine combined with lung-protective ventilation on lungs in patients undergoing thoracic surgery / 中华麻醉学杂志

ABSTRACT

Objective To evaluate protective effects of dexmedetomidine combined with lung-protective ventilation on lungs in patients undergoing thoracic surgery.Methods Eighty patients with normal pulmonary function,aged 40-64 yr,of American Society of Anesthesiologists physical status Ⅰ or Ⅱ,with body mass index of 20-25 kg/m2,scheduled for elective right lobectomy for lung cancer performed via a thoracoscope,were divided into 4 groups (n =20 each) using a random number tableconventional ventilation group (group C),dexmedetomidine combined with conventional ventilation group (group DC),lung-protective ventilation group (group P) and dexmedetomidine combined with lung-protective ventilation group (group DP).In DC and DP groups,dexmedetomidine was intravenously infused as a loading dose of 0.5 μg/kg (over 10 min) starting from 10 min before anesthesia induction,followed by an infusion of 0.6 μg · kg 1 · h-1 until the end of surgery.In C and DC groups,the tidal volume was set at 9 ml/kg,positive end-expiratory pressure 0 cmH2O,fraction of inspired oxygen 100％,respiratory rate 10-12 breaths/min,inspiratory/expiratory ratio 1 ∶ 2,and end-tidal pressure of carbon dioxide was maintained at 35-45 mmHg during both two-lung ventilation (TLV) and one-lung ventilation (OLV).In P and DP groups,the tidal volume was set at 6 ml/kg,positive end-expiratory pressure 5 cmH2O,fraction of inspired oxygen 70％,respiratory rate 14-16 breaths/min,i nspiratory/expiratory ratio 1 ∶ 2,and end-tidal pressure of carbon dioxide was maintained at 35-45 mmHg during TLV and OLV.Airway peak pressure (Ppe~),airway plateau pressure (Pp~t),dynamic lung compliance and airway resistance (Raw) were monitored and recorded immediately before OLV (T1),at 30 min,1 h and 2 h of OLV (T2-4) and at 15 min after restoration of TLV (T5).Arterial blood samples were collected at 10 min before induction of anesthesia (T0) and T1-5 for blood gas analysis,and oxygenation index was calculated.At T0,T1,T3,T4 and 2 and 24 h after surgery (T6,7),blood samples were taken from the right internal jugular vein for determination of the concentrations of serum tumor necrosis factor-alpha (TNF-α),interleukin-6 (IL-6) and high-mobility group box 1 protein (HMGB1) by enzyme-linked immunosorbent assay.Results Compared with group C,Raw was significantly decreased at T2-4 in group DC,Ppeak,Pplat and Raw were significantly decreased at T2-4 in P and DP groups,oxygenation index was significantly increased at T5 in DC and P groups,oxygenation index was significantly inereased at T2-5 in group DP,the concentrations of serum TNF-α and IL-6 were significantly decreased at T3,4 and T6,7 in P,DC and DP groups,and the concentrations of serum HMGB1 were significantly decreased at T6,7 in DC and DP groups (P＜0.05).Compared with group DC,Ppeak,Pplat and Raw were significantly decreased at T2-4,oxygenation index was increased at T3-5,and the concentrations of serum TNF-α and IL-6 were decreased at T3,4 and T6,7 in group DP (P＜0.05).Compared with group P,Raw was signifieantly decreased at T2-4,oxygenation index was increased at T2-5,and the concentrations of serum TNF-α and IL-6 were decreased at T3,4 and T6,7,and the concentrations of serum HMGB1 were decreased at T6,7 in group DP (P＜0.05).There was no significant difference in dynamic lung compliance at each time point among the four groups (P＞0.05).Conclusion The combination of dexmedetomidine and lung-proteetive ventilation provides protective effects on lungs and exterts better efficacy than either alone,and the mechanism may be related to inhibiting systemic inflammatory responses of patients undergoing thoracic surgery.