高原重体力劳动人群返回低海拔区后心功能的脱适应改变观察

De-adaptation change in cardiac function of laborers engaged in physical labor at high altitude after returning to lower altitude

目的观察高原重体力劳动对心功能的影响及返回低海拔地区后心功能的恢复情况。方法 96名快速进入高海拔(3700m)地区的男性官兵按照我国急性高原反应(AHAR)症状学计分方法进行评分和分度,并在从事重体力劳动50d及返回低海拔(1500m)后第2、15天清晨分别进行血清肌酸激酶同工酶(CK-MB)、乳酸脱氢酶同工酶(LDH-1)、Tei指数、左心室射血分数(LVEF)和左心室短轴缩短率(LVFS)测定,并与低海拔(1500m)地区的50名健康官兵(对照组)进行比较。结果 96名快速进入高海拔地区的男性官兵中共71例发生AHAR,其中重度24例,轻中度47例,其余25例未发生AHAR。血清CK-MB、LDH-1水平及Tei指数比较,重度AHAR组>轻中度AHAR组>无AHAR组>对照组,LVEF、LVFS比较,重度AHAR组<轻中度AHAR组<无AHAR组<对照组,组间两两比较差异均有统计学意义(P<0.01)。直线相关分析显示,海拔3700m暴露50d时,血清CK-MB、LDH-1与Tei指数呈显著正相关(r=0.625、0.598),与LVEF呈显著负相关(r=-0.716、-0.639),与LVFS亦呈显著负相关(r=-0.658、-0.727),差异均有统计学意义(P<0.01)。海拔3700m暴露50d时,血清CK-MB、LDH-1水平及Tei指数显著高于返回低海拔后第2天、第15天和对照组,且返回低海拔后第2天显著高于返回低海拔后第15天和对照组,LVEF、LVFS显著低于返回低海拔后第2天、第15天和对照组,且返回低海拔后第2天显著低于返回低海拔后第15天和对照组(P<0.01),返回低海拔后15d与对照组之间各指标无显著差异(P>0.05)。结论高原重体力劳动对部队官兵的心功能有明显损害,且随着AHAR程度的加重而加重,但返回低海拔后第2天即有显著改善,返回后第15天即恢复到正常水平。

Objective To assess the effects of physical labor on cardiac function of laborers at high altitude and changes in cardiac function after returning to lower altitude.Methods According to symptomatic scores on Chinese acute high altitude reaction（AHAR）,96 male officers and soldiers,who rapidly entered high altitude areas（3700m altitude）,and engaged in heavy physical work for 50 days,were be scored and graded.Levels of creatine kinase isoenzymes-MB（CK-MB） and lactic dehydrogenase isoenzyme-1（LDH-1） in the serum,Tei index,left ventricular ejection fraction（LVEF）,and left ventricular fractional shortening（LVFS） were measured in the 96 servicemen at the 50th day of residing at high altitude,and the 2nd and 15th day after returning to lower altitude（1500m altitude）,and the results were compared with that of 50 healthy controls residing at 1500m.Results Among the 96 male servicemen,71 developed AHAR,and 24 of them had severe AHAR,47 mild to moderate AHAR,and the rest 25 had no AHAR.Levels of serum CK-MB,LDH-1 and Tei index were higher in the severe AHAR group than in the mild to moderate AHAR group,higher in the mild to moderate AHAR group than in the no AHAR group and higher in the no AHAR group than in the healthy group.As far as the values of LVEF and LVFS were concerned,the severe AHAR group 〈 mild to moderate AHAR group 〈 no AHAR group 〈 control group.Significant difference was found in these levels between every two successive groups（P〈0.01）.Linear correlation analysis showed that levels of CK-MB and LDH-1 of persons staying at 3700m altitude for 50 days were positively correlated with Tei index（r= 0.625,0.598,respectively,P〈0.01）,and negatively correlated with LVEF（r=0.716,-0.658,respectively,P〈0.01）,and also negatively correlated with LVFS（r=-0.639,-0.727,respectively,P〈0.01）.Level of serum CK-MB,LDH-1 and Tei index at 3700m altitude for 50 days were significantly higher than those 2 days and 15 days after returning to 1500m altitude and those in control group（P〈0.01）,and were significantly higher on the 2th day than on the 15th day.Moreover,the values of LVEF and LVFS were significantly lower than those at 2 and 15 days after returning to 1500m altitude and those in control group（P〈0.01）,and significantly lower on the 2th day than on the 15th day.All parameters after 15 days returning to low altitude showed no significant difference compared with control group（P〉0.05）.Conclusion Heavy physical work at high altitude could obviously impair human cardiac function.The impairment may aggravate along with increase in severity of AHAR.However,cardiac function may be improved significantly after returning to low altitude for 2 days,and recover to normal status 15 days later.