阻力呼吸对正常人血流动力学的影响及其临床意义研究

Influence and clinical significance of resistant respiration on hemodynamics in normal man

目的 研究不同胸腔压力条件下心内各瓣口血流速度的变化 ,进一步验证呼吸影响心功能机制假说 ,为临床无创测定左心室舒张功能提供依据。方法 3 0名健康志愿者 ,分别测量平静呼吸及不同阻力呼吸时 (胸腔压力变化为 :-4mmHg、-8mmHg 和 -12mmHg)的各瓣口血流速度 ,不同胸压变化时不同呼吸相所测的各瓣口血流速度分别取平均值 ,计算呼吸性血流速度波动指数 (RVI)。结果 各瓣口血流速度在平静呼吸和胸腔压力变化为 -4mmHg时 ,RVI值差别无显著性意义。胸压变化为-8mmHg及 -12mmHg时 ,二尖瓣、主动脉瓣、三尖瓣和肺动脉瓣RVI值分别为 :12 .5 4% ,13 .19% ;6.2 3 % ,8.2 7% ;2 0 .2 7% ,2 4.3 6%和 6.45 % ,7.69%。上述各值与平静呼吸时的RVI值相比 ,差异有显著性意义 (P <0 .0 1或P <0 .0 0 1)。除二尖瓣和肺动脉瓣外 ,其余各瓣口RVI值在胸压变化为-8mmHg 和 -12mmHg 时差别有显著性意义 (P <0 .0 1)。结论 各瓣口RVI随胸压下降幅度增大而增大 ,这为RVI的临床应用、哮喘患者出现奇脉及呼吸影响心功能机制假说提供了依据。

Objective To observe the effects of resistant respiration on hemodynamics in normal man and to further verify the new proposal of the mechanism of respiratory effects on hemodynamics. Methods Pulsed wave Doppler spectra of the four cardiac valves were recorded with Sequoia 512 in 30 normal subjects with no apparent cardiac and pulmonary abnormalities aged from 22 to 55 years old.Electrocardiogram and respiratory tracing by a nasal thermistor were recorded simultaneously with the echocardiograms. The blood flow velocities of each valve during inspiration and expiration with different thoracic pressure changes were averaged separately and those were again averaged for at least 3 consecutive respiratory cycles, and the respiratory variation indices (RVI) were calculated and compared. Results There existed no significant difference in all the cardiac valves between quiet respiration and resistant respiration with thoracic pressure change at -4 mm Hg . With the thoracic pressure change at -8 mm Hg and -12 mm Hg , the RVI were 12.54 %, 13.19 %; 6.23 %, 8.27 %; 20.27 %, 24.36 %; 6.45 %, 7.69 %.All the above RVI values had significant difference over those during quiet respiration (P< 0.01 or P< 0.001 ). Except the RVI in pulmonary valve, all the RVI values of the other three cardiac valves had significant difference between the thoracic pressure change at -12 mm Hg and at -8 mm Hg (P< 0.01 ). Conclusions RVIs of all cardiac valves decreased with the increase of the negative thoracic pressure change, which could explain the occurrence of pulsus paradoxus in the patients with asthma and further verified our hypothesis of respiratory influence on cardic function.