Objectives: The optimum chest compression site (P_optimum) in children is debated: European Resuscitation Council recommends one finger breadth above the xiphisternal joint, whereas American Heart Association proposes the lower sternal half. Using a coordinate system imposed on CT, we aimed to determine the pediatric P_optimum to maximize stroke volume, the key point for successful cardiopulmonary resuscitation, while minimizing hepatic injury.
Design: Retrospective, cross-sectional study.
Setting: University hospital.
Patients: Children 1-15 years old who underwent chest CT.
Interventions: None.
Measurements and main results: We defined zero point (0, 0) as the center of the xiphisternal joint designating leftward and upward directions of the patients as positive on each axis. P_optimum (x_max. left ventricle, y_max. left ventricle) was defined as the center of the maximum diameter of the left ventricle, whereas P_aorta (x_aorta, y_aorta) as that of the aortic annulus. To compress the left ventricle exclusively, y_max. left ventricle should range above the y coordinate of hepatic dome (y_liver_dome) and below y_aorta. Data were presented as median (interquartile range) and compared among age groups 1.0-5.0, 5.1-10.0, and 10.1-15.0 years using Kruskal-Wallis test. For universal application regardless of age, y coordinates were converted into relative ones with unit of sternal top: 1 unit of sternal top was the y coordinate of the sternal top. A total of 163 patients were enrolled, median age 8.8 year (4.2-14.3 yr). Among age groups, no significant difference was observed in y_max. left ventricle, relative y_max. left ventricle, y_aorta, and y_liver_dome: 1.0 cm (0.1-1.9 cm), 0.10 unit of sternal top (0.01-0.18 unit of sternal top), 0.39 unit of sternal top (0.30-0.47 unit of sternal top), and -0.14 unit of sternal top (-0.25 to -0.03 unit of sternal top), respectively. The probability to compress the left ventricle exclusively was greater than or equal to 96% when placing hand at 0.05-0.20 unit of sternal top. Subgroup analysis demonstrated the following regression equation: x_max. left ventricle (mm) = 0.173 × (height in cm) + 13 (n = 106; p < 0.001; R = 0.278).
Conclusions: Theoretically, pediatric P_optimum is located 1 cm (or 0.1 unit of sternal top) above the xiphisternal joint.