空气或纯氧复苏宫内窒息新生大鼠血气和大脑SOD水平的比较

Effects of resuscitation with air or oxygen on blood gas and cerebral SOD concentration in neonatal rats with intrauterine asphyxia

目的 比较采用空气或纯氧复苏宫内窒息新生大鼠效果,为寻求合理的新生儿复苏气源提供一些理论依据.方法 将77只胎龄21 d的SD新生大鼠随机（随机数字法）分为三组：对照组（SHAM组）;正常新生大鼠,剖宫产娩出;空气复苏组（RAR组）,宫内窒息新生大鼠,剖宫产娩出后采用空气复苏;纯氧复苏组（POR组）,宫内窒息新生大鼠,剖宫产娩出后采用纯氧复苏.比较各组新生大鼠复苏后0 h,6 h及24 h 血气结果和大脑超氧化物歧化酶（superoxide dismutase SOD）水平以及复苏后新生大鼠死亡率.结果 POR组复苏后0 h,新生大鼠动脉血氧分压（PaO2）（69.0±8.2）mmHg,与RAR组新生大鼠PaO2（55.5±10.3）mmHg比较,差异具有统计学意义（P=0.004）,POR组复苏后6 h及24 h,新生大鼠PaO2与RAR组比较,差异均无统计学意义（P＞0.05）.POR组复苏后0 h及6 h,新生大鼠大脑SOD值分别为（38.3±9.8）U/mgprot和（8.6±3.6）U/mgprot,与RAR组新生大鼠大脑SOD值（53.8±10.6）U/mgprot和（13.0±4.6）U/mgprot比较,差异均具有统计学意义（P值为0.003和0.04）,POR组复苏后24 h,新生大鼠大脑SOD值为（17.6±6.8）U/mgprot,与RAR组（19.8±6.3）U/mgprot比较,差异无统计学意义（P=0.53）.RAR组和POR组在复苏后0 h,6 h及24 h新生大鼠大脑SOD水平,与对照组比较,差异均有统计学意义（P＜0.05）.POR组新生大鼠复苏后0 h死亡率3.7%,与RAR组比较,差异无统计学意义（P＞0.05）.结论 纯氧或空气复苏窒息新生大鼠,复苏后短期死亡率相似,但纯氧复苏后窒息新生大鼠出现短暂血氧分压升高,同时大脑SOD在一定时期内维持较低水平.

Objective To test the effects of restuscitation with air or oxygen on the blood gas and cerebral superoxide dismutase （SOD） concentration in neonatal rats with experimental intrauterine asphyxia. Method Seventy-seven neonatal rats were randomly （random number） divided into three experimental groups： sham operation group （SHAM）, air resuscitation group （AR）, and oxygen resuscitation group （OR）. In groups AR and OR, animal models of intrauterine asphyxia were established and then resuscitated with air （AR） or oxygen （OR） for 30min. Comparison was made between groups including the mortality 0 hour after resuscitation, and the levels of blood gas and cerebral SOD concentrations 0 h, 6 h and 24 h after resuscitation. Results Mortality of neonatal rats in SHAM group, AR group and OR group were 0 （0/24）, 0 （0/26） and 3.7% （1/27）, respectively （P 〉0.05）. The average levels of blood PaO2 in OR group and AR group 0 h after resuscitation were （69.2 ± 8.2）mmHg and （55.5±10.3） mmHg,respectively （P=0.004）. Blood pH and PaCO2 and BE levels in OR group 0 h after resuscitation were not significantly different from those in AR group （P〉0.05）. Blood pH, PO2, PCO2and BE levels in OR group were also not significantly different from those in AR group 6 h and 24 hours after resuscitation. The average concentrations of cerebral SOD in OR group 0 h and 6 hours after resucitation were （38.3±9.8） U/mgprot and （8.6±3.6） U/mgprot, and those in AR group were （53.8± 10.6） U/mgprot and （13.0±4.6） U/mgprot, respectively （P = 0.003, 0.04）. The cerebral SOD concentration in OR group 24 hours after resuscitation was not significantly different from that in AR group （P〉0.05）. The cerebral SOD concentrations in SHAM group 0 h,6 h and 24 hours after resuscitation were much higher than those in OR group and AR group （P〈0.05）. Conclusions Resuscitation with air is as good as pure oxygen in neonatal resuscitation, in respect of early mortality and improvement of acidosis in neonatal rats after intrauterine asphyxia. Resuscitation with air will generate less radical oxygen species than pure oxygen in neonatal rats after intrauterine asphyxia.