Hand placement during chest compressions in parturients: a pilot study to identify the location of the left ventricle using transthoracic echocardiography

Background: Current guidelines for maternal cardiopulmonary resuscitation recommend the hands be placed on the lower half of the sternum for compressions. We sought to evaluate the effect of the gravid uterus and left uterine displacement on the position of the left ventricle (LV) using transthoracic echocardiography. Methods: We enrolled 20 women in the third trimester of a singleton pregnancy. Transthoracic echocardiography images in the supine and left lateral position, using a 30° wedge, were acquired. Parasternal long and short axis views of the LV were obtained at the lower half of the sternum and at the ideal imaging window (best image of mid-LV at 90° transducer orientation) The primary aim was to evaluate the distance between the distal end of the xiphoid and the location of the best imaging window of the LV. Results: The cohort included women without prior anatomical cardiac disease. The LV was best visualized 5.8 (±2) cm cranial to the distal end of the xiphoid in the supine position and 6.1 (±2) cm in the lateral position (P=0.6), using the left parasternal border as a reference. No lateral cardiac displacement was evidenced in either position. Conclusions: This pilot study used transthoracic echocardiography to document the position of the LV during the third trimester of pregnancy. The LV was located approximately 6 cm cranial to the distal tip of the xiphoid process. Further validation is required before recommending changes in hand placement during maternal cardiopulmonary resuscitation.