Determination of the theoretical personalized optimum chest compression point using anteroposterior chest radiography

Abstract

Objective There is a traditional assumption that to maximize stroke volume, the point beneath which the left ventricle (LV) is at its maximum diameter (P_max.LV) should be compressed. Thus, we aimed to derive and validate rules to estimate P_max.LV using anteroposterior chest radiography (chest_AP), which is performed for critically ill patients urgently needing determination of their personalized P_max.LV. Methods A retrospective, cross-sectional study was performed with non-cardiac arrest adults who underwent chest_AP within 1 hour of computed tomography (derivation:validation = 3:2). On chest_AP, we defined cardiac diameter (CD), distance from right cardiac border to midline (RB), and cardiac height (CH) from the carina to the uppermost point of left hemi-diaphragm. Setting point zero (0, 0) at the midpoint of the xiphisternal joint and designating leftward and upward directions as positive on x-and y-axes, we located P_max.LV (x_max.LV, y_max.LV). The coefficients of the following mathematically inferred rules were sought: x_max.LV = α0*CD-RB; y_max.LV = β0*CH+γ0 (α0: mean of [x_max.LV+RB]/CD; β0, γ0: representative coefficient and constant of linear regression model, respectively). Results Among 360 cases (52.0 ± 18.3 years, 102 females), we derived: x_max.LV = 0.643*CD-RB and y_max.LV = 55-0.390*CH. This estimated P_max.LV (19 ± 11 mm) was as close as the averaged P_max.LV (19 ± 11 mm, P = 0.13) and closer than the three equidistant points representing the current guidelines (67± 13, 56± 10, and 77± 17 mm; all P < 0.001) to the reference identified on computed tomography. Thus, our findings were validated. Conclusion Personalized P_max.LV can be estimated using chest_AP. Further studies with actual cardiac arrest victims are needed to verify the safety and effectiveness of the rule.

Hand Placement During Chest Compressions in Parturients: A Pilot Study to Identify the Location of the Left Ventricle Using Transthoracic Echocardiography

“…2 Kim et al determined the point from anteroposterior chest radiography in critically ill patients. 3 Furthermore, contrary to the traditional theory, the point of maximal LV diameter may not be optimal for chest compression. Patients with point of maximal LV diameter located at close to the mid-sternum have not shown better ROSC or survival-to -discharge rate.…”

“…They suggested the estimated position with chest radiography is not necessarily located at the mid-sternum 2. Kim et al determined the point from anteroposterior chest radiography in critically ill patients 3. Furthermore, contrary to the traditional theory, the point of maximal LV diameter may not be optimal for chest compression.…”

“…The compression to this point can lead to the increased stroke volume and coronary perfusion, resulting in successful return of spontaneous circulation (ROSC) and good outcome. Chest radiography [2][3][4] and computed tomography 5 have been used in order to estimate or locate the point of maximum LV diameter. Cho et al recently estimated the position of maximum LV diameter using posteroanterior chest radiography and compared with personalized optimum chest compression point on computed tomography.…”