Discussion
LVOT, volume of cardiac output, cardiac arrest, ventricular compression, chest compression, injuries
CARDIAC ARREST, COMPLICATIONS
Direct ventricular compression is theoretically the most effective method for generating blood flow during CPR. Our primary concern is ensuring that the level of LV max targets a volume of cardiac output maximization while avoiding compression of outflow vesselsWith concern of anatomical variants among populations, Lee et al.Nevertheless, during the actual CPR, patients are usually in arm down position with mostly expiration and sometimes inspiration in the case of assisted ventilation. The previous studiesA few studies reported the optimal location of hand placement during CPR. In 2007, Shin et al. suggested, based on chest computed tomography (CT), that positioning the hands at the inter-nipple line mostly affected the root of the aorta, ascending aorta, and left ventricular outflow tract (LVOT) rather than the LV (20.6%)Concerns for organ complications from chest compression includes compression on the LVOT and injuries to the liver and stomachHwang et al.There were 87.3% (178/204) and 53.4% (109/204) of the subjects whose uppermost part of the liver and stomach were located in the thoracic region above the tip of xiphoid process with IAR position. Nearly all of these subjects had their uppermost part of the liver and stomach found in lower half of the sternum level in IAR position, majority in the 1st quarter from TOX. There is limited evidence in literature for adjusting the position of the intraabdominal organs during CPR from IAR position. However, assuming diaphragmatic elevation during expiration, majority of the subjects would have their liver and stomach located above tip of xiphoid process. This may support results of previous studies which reported liver and stomach laceration during CPRThe 2005 edition of the AHA guideline for CPR previously recommended inter-nipple line level as the proper hand position for chest compressionThere were several limitations in this study. The primary limitation of this study is that the participants were not individuals who had experienced cardiac arrests. In other words, since the study cohort differs from the population of cardiac arrest patients, it is important to exercise caution when generalizing the findings of this study to individuals who have suffered cardiac arrests. Second, this is a pilot study with a limited number of subjects as part of a multi-regional investigation. Further data collection of a larger group of subjects in different regions of the country would more closely represent Thai population. Nevertheless, the results could represent trends of optimal hand position during CC in Thai individuals. Third, the actual heights of anatomical landmarks during expiration and arm down position as of cardiac arrests’ postition were not determined due to the routine CT scan protocols in IAR position. However, we attempted to adjust these measurements (LV