Influence of the Method of Alleviation of Aorto-Caval Compression on the Trans-Hepatic Ultrasound-Assessed Inferior Vena Cava Diameter In Pregnant Patients

Cardiac arrest during pregnancy is rare but may result in poor maternal and fetal outcome. Because of its rare occurrence and ethical issues this topic is not very well studied and many questions pertaining to maternal resuscitation remain unanswered. One of the challenging aspects of cardiopulmonary resuscitation in a term pregnant patient is the ideal positioning during chest compressions. International societies have made recommendations regarding management of pregnant patients during cardiac arrest. They advocate the use of left lateral position with 30 degrees tilt or manual uterine displacement. However these recommendations are not based on high level of evidence. Ultrasound has been used to visualize the change in diameter of great vessels to determine the volume status or adequacy of blood circulation of these patients. This approach can be used to study the adequacy of blood circulation of pregnant patients in different positions. The objective of this study is to compare the change in Inferior vena cava diameter obtained with pregnant women in either the left lateral tilt or in the supine position with a manual uterine displacement, compared to the left lateral position and the supine position.

Our hypothesis is that the inferior vena cava diameter obtained in the supine position with manual left uterine displacement would be larger as compared to that obtained with women positioned with a 30-degree tilt.