Changes of Aortic Dimensions as an Evidence of Cardiac Pump Mechanism During Cardiopulmonary Resuscitation: Transesophageal Echocardiographic Observation

Hwang,  Sung Oh; Kim,  Sun Man; Cho,  Jun Hwi; Oh,  Bum Jin; Kim,  Sung Hwan; Kang,  Ku Hyun; Lee,  Kang Hyun; Lee,  Seung Hwan; Yoon,  Jung Han; Choe,  Kyung Hoon

J Korean Soc Emerg Med > Volume 10(1); 1999 > Article

Original Article

Journal of The Korean Society of Emergency Medicine 1999;10(1): 60-69.

Changes of Aortic Dimensions as an Evidence of Cardiac Pump Mechanism During Cardiopulmonary Resuscitation: Transesophageal Echocardiographic Observation

Sung Oh Hwang, Sun Man Kim, Jun Hwi Cho, Bum Jin Oh, Sung Hwan Kim, Ku Hyun Kang, Kang Hyun Lee, Seung Hwan Lee, Jung Han Yoon, Kyung Hoon Choe

ABSTRACT

BACKGROUND: Although the cardiac pump mechanists and the thoracic pump mechanism have been suggested, the mechanism of blood flow generated by precordial compression in human remains controversial. We hypothesized that, during compression systole, the proximal descending thoracic aorta would be distended by forward blood flow if the heart acts as a pump, and be contacted or unchanged if increased intrathoracic pressure generates blood flow.
METHODS:
Fourteen patients with cardiac angst underwent transesophageal echocardiogaphy to verify the morphologic changes of the descending thoracic aorta during standard manual cardiopulmonary resuscitation. The aortic dimensions including cross sectional area and diameters at the end of compression and of relaxation were measured proximal to and at the maximal compressing site of the descending thoracic aorta.
RESULTS:
At the point of maximal compression, deformations of the descending thoracic aorta were observed during compression in all patients and ratio of the longest to shortest diameter of the aorta deceased during compression than relaxation(0.58+/-0.15 versus 0.81+/-0.11, p=0.001). Cross sectional area of the aorta at the maxim compression deceased during compression than relaxation(3.01+/-1.91 versus 7.26+/-14.70 cm2, p=0.035). Ratio of the longest to shortest diameter of the proximal descending thoracic aorta remained unchanged during compression and relaxation(1.0+/- 0.88 versus 1.0+/-0.9, p=0.345). Cross sectional area of the proximal descending thoracic aorta increased during compression than relaxation(4.81+/-2.86 versus 4.29+/-2.51 cm2, p=0.011).
CONCLUSION:
Distention of the proximal descending thoracic aorta and deformation of the aorta at the maximal compression during the compression systole suggests that the heart act as a pump during standard manual cardiopulmonary resucitation in human.