Effects of different doses of dexmedetomidine on lung injury in pediatric patients undergoing open heart surgery under cardiopulmonary bypass / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effects of different doses of dexmedetomidine on lung injury in pediatric patients undergoing open heart surgery under cardiopulmonary bypass (CPB).Methods Forty-eight pediatric patients,aged 7 months-3 yr,of ASA physical status Ⅱ or Ⅲ,scheduled for elective repair of ventricular septal defect under CPB,were randomly divided into 4 groups (n =12 each) using a random number tablecontrol group (group C) and 3 different doses of dexmedetomidine groups (D1-3 groups).Anesthesia was induced with midazolam,fentanyl and vecuronium.The patients were endotracheally intubated and mechanically ventilated.In D1-3 groups,dexmedetomidine 0.5μg/kg (initial dose) was given over more than 10 min,followed by continuous infusion at 0.1,0.3 and 0.5 μg· kg-1 · h-1,respectively,until the end of operation.The equal volume of normal saline was given instead of dexmedetomidine in group C.Before administration (T1),and at 2,6 and 12 h after termination of CPB (T2-4),blood samples were collected for determination of plasma tumor necrosis factor-α (TNF-α),interleukin-6 (IL-6) and IL-8 concentrations and for blood gas analysis.Respiratory index (RI),oxygenation index (OI) and lung compliance (CL) were calculated.Results The plasma concentrations of TNF-α and IL-8 at T2-4 and IL-6 at T3,4 were significantly lower in D2,3 groups than in group C.Compared with group D1,the plasma concentrations of TNF-α,IL-8 and RI were significantly decreased,and OI and CL were increased at T2-4 in D2-3 groups,and the plasma IL-6 concentrations at T3,4 in group D2 and at T2-4 in group D3 were decreased.The plasma concentrations of TNF-α and IL-6 were significantly lower,while OI and CL were higher at T2,3,and the plasma concentrations of IL-8 and RI were lower at T2-4 in group D3 than in group D2.Conclusion Dexmedetomidine can reduce lung injury in pediatric patients undergoing open heart surgery under CPB and promote the lung function after CPB possibly through inhibiting inflammatory responses to CPB dosedependently.