有氧前臂运动试验在线粒体肌病及脑肌病筛选中的应用

Auxiliary diagnosis of aerobic forearm exercise in mitochondriai myopathy and encephalopathy

目的探讨血氧分析和乳酸测定在有氧前臂运动试验中的应用,及其对于线粒体肌病及脑肌病的筛选诊断意义。方法对42例确诊的线粒体肌病及脑肌病(MM)、40名健康人(HC)和40例其他肌病患者(PC)进行有氧前臂运动试验,受试者以40%最大收缩力、1 s 间隔做反复等长收缩前臂运动4 min,在运动前、运动中及运动后行血氧分析和乳酸测定。结果运动中,MM 组、HC 组和 PC 组静脉 PO_2(mm Hg,1 mm Hg=0.133 kPa)分别从41.2±12.6降至39.5士16.2,50.5±14.4降至30.8±13.1,50.1±7.9降至44.3±35.5,HC 组下降幅度明显高于其他2组(F=6.34,P<0.01);3组静脉 SO_2分别从70.5%±15.8%降至64.4%±15.2%,82.4%±10.0%降至47.2%±11.7%,84.6%±6.3%降至51.1%±9.3%,MM 组下降幅度明显低于其他2组(F=91.95,P<0.01)。运动后,静脉 PO_2、SO_2 3组间差异无统计学意义。3组运动中血乳酸(mmol/L)分别由2.7±3.2升至5.1±3.8,1.1±0.5升至3.1±1.9,1.3±0.8升至3.5±1.8。运动后,3组血乳酸分别为3.8±3.5、1.8±1.0、2.3±1.4,MM 组高于其余2组(F=8.50,P<0.01)。结论线粒体肌病及脑肌病患者运动时氧摄取能力比健康人及其他肌病患者下降。有氧前臂运动试验运用血氧分析和乳酸测定的方法,是一种行之有效的线粒体肌病及脑肌病筛查试验,对于线粒体肌病及脑肌病的辅助诊断有意义,其敏感性及特异性较高。

Objective To investigate blood gas analysis and lactic acid evaluation in aerobic forearm exercise and the significance of aerobic forearm exercise for the auxiliary diagnosis of mitochondrial myopathy and encephalopathy patients. Methods Forty-two patients with mitochondrial myopathy and encephalopathy patients, 40 healthy control, and 40 patients control were studied. They performed a protocol under aerobic exercise conditions, consisting of intermittent forearm exercise for 4 minutes at 40% of intented maximal voluntary contraction force. Blood samples were collected to monitor blood gas and plasma lactate before, during and after exercise. Results During exercise venous PO2 （mm Hg, 1 mm Hg = 0. 133 kPa） decreased in mitochondrial myopathy and encephalopathy patients from 41.2± 12. 6 to 39. 5 ± 16. 2, whereas PO2 fell from 50. 5 ± 14. 4 to 30. 8 ± 13.1 in healthy control and from 50. 1 ±7.9 to 44. 3 ±35.5 in patient control. Venous PO2 decreased much more in healthy control group than the other 2 groups （ F = 6.34,P 〈 0. 01 ）. During exercise venous SO2 dropped in mitochondrial myopathy and encephalopathy patients from70.5% ±15.8% to 64.4% ±15.2%, from 82.4% ±10.0% to 47.2% ±11.7% in healthy control and from 84. 6% ±6. 3% to 51.1% ±9. 3% in patient control. Venous SO2 decreased much less in mitochondrial myopathy and encephalopathy patients than the other 2 groups （ F = 91.95, P 〈 0. 01 ）. Recovery venous PO2 and SO2 were similar in all subjects. During exercise resting plasma lactate （mmol/L） rose from 2.7 ±3.2 to 5. 1 ±3.8 in mitochondrial myopathy and encephalopathy patients,from 1.1 ±0. 5 to 3.1 ± 1.9 in healthy control and from 1.3 ± 0. 8 to 3.5 _± 1.8 in patient control. Recovery plasma lactate in mitochondrial myopathy and encephalopathy patients was 3.8 ± 3.5, 1.8 ± 1.0 in healthy control ,2. 3 ± 1.4 in patient control. Recovery plasma lactate in mitochondrial myopathy and encephalopathy patients was higher than the other 2 groups （ F = 8.50, P 〈 0. 01 ）. Conclusions The oxygen uptake ability during exercise of mitochondrial myopathy and encephalopathy patients decreases compared with healthy people and other myopathy patients. Aerobic forearm exercise is a valuable method in auxiliary diagnosis of mitochondrial myopathy and encephalopathy patients by means of monitor blood gas and plasma lactate with high sensitivity and specificity are high.