Schummer W, Schummer C, Schelenz C, Brandes H, Stock U, Müller T, Leder U, Hüttemann E
Clinic for Anaesthesiology and Intensive Care Medicine, Friedrich-Schiller University of Jena, Erlanger Allee 103, D-07747 Jena, Germany.
Br J Anaesth. 2004 Aug;93(2):193-8. doi: 10.1093/bja/aeh191. Epub 2004 Jun 25.
The classic increase in P wave size, known as 'P-atriale', is a widely accepted criterion for determination of proper positioning of central venous catheter tips. Recent transoesophageal echocardiography (TOE) studies did not confirm intra-atrial position despite advancing the central venous catheter further than indicated by ECG guidance. We postulate that the pericardial reflection rather than the entry into the right atrium corresponds to the ECG changes. In order to test our hypothesis we sought to determine the anatomical substrate for the electrical changes in an animal study. Subsequently, a modified version of the study was undertaken in man and is also reported.
In six juvenile pigs the left external jugular vein and right carotid artery were cannulated. A triple-lumen central venous catheter was positioned by ECG guidance using a Seldinger wire as an exploring electrode. The venous and arterial catheters were suture fixed 2 cm beyond the onset of an increase in P wave size. The corresponding anatomical catheter tip position was determined by open exploration of the vessels and the heart. Subsequently the catheter tip position (during advancement) of a pulmonary artery catheter and the corresponding electrical ECG changes were examined in 10 patients during open chest cardiac surgery.
All catheters-arterial and venous, in animals and humans-revealed an increase in size of the P wave as well as the QRS complex. All venous catheters were positioned in the superior vena cava, beyond the pericardial reflection but outside the right atrium. All arterial catheters were positioned in the ascending aorta thus also beyond the pericardial reflection.
The start of an increase in P wave size does not correspond with the entrance of the right atrium. The anatomic equivalent for the electrophysiological changes of the ECG is the pericardial reflection. ECG guidance is unable to distinguish between venous and arterial catheter position.
经典的P波大小增加，即所谓的“P波增大”，是确定中心静脉导管尖端正确位置的广泛接受的标准。最近的经食管超声心动图（TOE）研究表明，尽管中心静脉导管推进的距离超过了心电图引导所指示的范围，但仍未证实导管尖端位于心房内。我们推测，心电图变化对应的是心包折返而非进入右心房。为了验证我们的假设，我们试图在一项动物研究中确定电变化的解剖学基础。随后，我们在人体中进行了该研究的改良版本，并报告如下。
在6只幼年猪身上，分别插入左颈外静脉和右颈动脉导管。使用Seldinger导丝作为探测电极，在心电图引导下放置三腔中心静脉导管。将静脉导管和动脉导管在P波大小开始增加2 cm处缝合固定。通过对血管和心脏进行开放探查来确定相应的解剖学导管尖端位置。随后，在10例开胸心脏手术患者中，检查肺动脉导管的导管尖端位置（推进过程中）及相应的心电图电变化。
动物和人类的所有导管（动脉导管和静脉导管）均显示P波及QRS波群大小增加。所有静脉导管均位于上腔静脉，在心包折返之外但不在右心房内。所有动脉导管均位于升主动脉，因此也在心包折返之外。
P波大小开始增加并不与右心房入口相对应。心电图电生理变化的解剖学等效部位是心包折返。心电图引导无法区分静脉导管和动脉导管的位置。
