胸压对三尖瓣反流速度和肺动脉压测定的影响

目的 应用超声心动图观察平静呼吸情况下胸压对三尖瓣反流速度的影响及规律,为超声心动图准确测定肺动脉压和验证呼吸影响心功能机制新假说提供依据.方法 对50例三尖瓣反流患者,利用二维及多普勒超声心动图记录不同呼吸时相三尖瓣反流速度和跨瓣压,观察不同呼吸时相时三尖瓣反流速度的变化规律.结果 呼吸对三尖瓣反流速度有确定影响,反流速度与呼吸时相关系表现有三种类型:第一种为吸气相速度增加,呼气相速度减小;第二种表现与第一种相反;第三种为速度变化表现为随机性.结论 呼吸性胸压变化对三尖瓣反流速度有明确影响,提示用多普勒法无创测定肺动脉压时需要将呼吸停止在呼吸时相的中期,并保持测定过程中胸压稳定,以提高测定准确性.

Study of effects of the thoracic pressure on the velocity of tricuspid regurgitation and estimation of pulmonary artery systolic pressure

Objective To observe the effects and the mechanism of the thoracic pressure variation on the velocity of tricuspid regurgitation in quiet respiration, to accurately estimate the pulmonary artery systolic pressure,and to verify the new proposed mechanism of respiration effects on hemodynamics using echocardiography. Methods Continuous-wave Doppler spectra of tricuspid regurgitation were recorded with Sequoia 512 in 50 patients who had stable tricuspid regurgitation. Electrocardiogram and respiratory tracing were recorded simultaneously. The velocities and the pressure gradients were recorded during different respiration phases for analyzing. Results Respiration reliably affected on tricuspid regurgitant velocity. There were three patterns of manifestation:①The velocity increased in the inspiratory phase. ②The velocity decreased in the inspiratory phase. ③The velocity changed randomly. Conclusions Thoracic pressure variations had definite effects on the velocity of tricuspid regurgitation and tricuspid gradient. This research indicated that to obtain accurate and reliable Doppler echocardiographic measurement of the pulmonary artery systolic pressure, the measurement should be at the time between inspiration and expiration.