Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
Med Sci Sports Exerc. 2010 Sep;42(9):1688-95. doi: 10.1249/MSS.0b013e3181d85dc3.
Acute voluntary lung hyperinflation provoked by glossopharyngeal insufflation (GI) elicits numerous, possibly deleterious, effects on the cardiopulmonary system by increasing intrathoracic pressures far above normal values. This study quantifies acute pulmonary hemodynamics during GI using phase-contrast magnetic resonance imaging (MRI).
Hemodynamic parameters were measured in nine elite male breath hold divers with a mean age of 30 yr (range = 20-43 yr) by velocity-encoding cine (VEC)-MRI of the main pulmonary artery (PA) before, during, and after GI. Simultaneously, GI-lung volume (GIVEC-MRI) was measured by MR-compatible spirometry.
Hemodynamic parameters were associated with GIVEC-MRI. Highly significant changes during GI were shown for the mean flow in the PA, which decreased by 45% (P < 0.007), and right ventricular output and cardiac index, which decreased by 41% and 40%, respectively (P < 0.007). Acceleration time also decreased highly significant by 36% during GI (P < 0.007). All hemodynamic parameters except acceleration time returned to baseline after GI.
Acute voluntary lung hyperinflation mimics changes seen in pulmonary arterial hypertension, but unlike the latter, these changes are fully reversible shortly after cessation of voluntary lung hyperinflation. Persistent changes due to repetitive GI could not be detected.
通过使咽鼓管充气来诱发急性自愿性肺过度充气，会使胸腔内压力大大高于正常水平，从而对心肺系统产生许多可能有害的影响。本研究使用相位对比磁共振成像（MRI）来定量测量咽鼓管充气期间的急性肺血液动力学。
通过对 9 名精英男性潜水员进行速度编码电影（VEC）-MRI 主肺动脉（PA）的测量，这些潜水员的平均年龄为 30 岁（范围为 20-43 岁），分别在咽鼓管充气前、充气中和充气后进行测量。同时，通过与磁共振兼容的肺活量计测量咽鼓管充气-肺容量（GIVEC-MRI）。
血流动力学参数与 GIVEC-MRI 相关。在咽鼓管充气期间，PA 的平均流量显著降低了 45%（P < 0.007），右心室输出和心指数分别降低了 41%和 40%（P < 0.007），这些变化非常显著。加速度时间也在咽鼓管充气期间显著降低了 36%（P < 0.007）。除了加速度时间之外，所有血流动力学参数在咽鼓管充气后均恢复到基线。
急性自愿性肺过度充气模拟了肺动脉高压中所见的变化，但与后者不同的是，这些变化在自愿性肺过度充气停止后很快就完全可逆。由于重复进行咽鼓管充气而导致的持续变化无法被检测到。
