Todd T R, Baile E M, Hogg J C
Am Rev Respir Dis. 1978 Sep;118(3):613-6. doi: 10.1164/arrd.1978.118.3.613.
To test the hypothesis that the position of a pulmonary arterial wedge catheter might affect its ability to measure left atrial pressure, we inserted 2 wedge catheters, one superiorly, and one dependently, in supine dogs. The position of the catheter tips and the zero level of the transducers were located on a lateral chest radiograph so that by referencing the transducers to the posterior surface of the lung and measuring the height of the catheter tip above that reference point, the zones in which the catheter tips were located were determined. When both catheters were in Zone III (pulmonary arterial pressure greater than left atrial pressure greater than alveolar pressure), the wedge pressures accurately reflected left atrial pressure. However, during hemorrhage, left atrial pressure decreased, and when the pulmonary arterial wedge catheter placed superiorly came under Zone II conditions (pulmonary arterial pressure greater than alveolar pressure greater than left atrial pressure), it recorded a constant pressure somewhat greater than left atrial pressure; the pulmonary arterial wedge catheter placed dependently, which remained in Zone III, continued to reflect left atrial pressure. We conclude that a pulmonary arterial wedge catheter measures left atrial pressure only when it is located in Zone III.
为了验证肺动脉楔压导管的位置可能会影响其测量左心房压力能力的这一假设，我们在仰卧位的犬身上插入了2根楔压导管，一根朝上，一根朝下。导管尖端的位置以及换能器的零水平在胸部侧位X线片上确定，这样通过将换能器参考肺的后表面，并测量导管尖端高于该参考点的高度，就可以确定导管尖端所在的区域。当两根导管都位于Ⅲ区（肺动脉压＞左心房压＞肺泡压）时，楔压能准确反映左心房压力。然而，在出血过程中，左心房压力下降，当朝上放置的肺动脉楔压导管进入Ⅱ区（肺动脉压＞肺泡压＞左心房压）时，它记录到一个略高于左心房压力的恒定压力；而朝下放置的肺动脉楔压导管仍位于Ⅲ区，继续反映左心房压力。我们得出结论，肺动脉楔压导管只有位于Ⅲ区时才能测量左心房压力。
