Effects of dexmedetomidine on cerebral oxygen and glucose metabolism in patients undergoing mitral valve replacement under cardiopulmonary bypass / 中华麻醉学杂志

ABSTRACT

ObjectiveTo investigate the effects of dexmedetomidine on cerebral oxygen and glucose metabolism in patients undergoing mitral valve replacement under cardiopulmonary bypass (CPB).Methods Fiftyeight ASA Ⅱ or Ⅲ patients of both sexes aged 32-64 yr weighing 52-90 kg undergoing mitral valve replacement were randomly divided into 2 groups (n =29 each) control group (group C) and dexmedetomidine group (group D).Dexmedetomidine was infused iv at 0.5 μg· kg- 1 · h- 1 starting after tracheal intubation until the end of operation in group D,while in group C equal volume of normal saline was infused instead of dexmedetomidine.Blood samples were collected from radial artery and jugular venous bulb for blood gas analysis and determination of glucose and lactate concentrations before CPB (T1,nasopharyngeal temperature =36 ℃ ),during CPB (T2,nasopharyngeal temperature =30 ℃ ),immediately and 30 min after restoration of spontaneous heart beat ( T3,T4 ).Arterial O2 content ( CaO2 ),arteriovenous O2 content difference ( Da-jvO2 ),cerebral extraction of O2 ( CEO2 ),arteriovenous glucose and lactate content differences (Da-jvGlu and Da-jvLac) were calculated.ResultsThe Da-jvO2 and CEO2 were significantly decreased at T2 in group D as compared with group C.There was no significant difference in CaO2,Da-jvGlu and Da-jvLac between the 2 groups.ConclusionDexmedetomidine can reduce cerebral O2 metabolism and help maintain the balance between cerebral O2 supply and demand but has no effect on cerebral glucose metabolism in patients undergoing mitral valve replacement under CPB.