This study aimed to determine if a simplified, easy-to-use ultrasound device (bladder scanner) can reliably locate the heart when applied over the intercostal spaces of the anterior thorax in supine patients.  Using a bladder scanner to evaluate the left sternal border and mid-clavicular lines, we determined the maximal scan volumes at 10 intercostal spaces for each participant.  Conclusions In this cross-sectional study of healthy volunteers, an easy-to-use ultrasound device (bladder scanner) was able to reliably localize the heart. 
bladder scanner
Use of a Simple Ultrasound Device to Identify the Optimal Area of Compression for Out-of-Hospital Cardiac Arrest.Background Despite automated defibrillation and compression-first resuscitation, out-of-hospital cardiac arrest (OHCA) survival remains low.  This study aimed to determine if a simplified, easy-to-use ultrasound device (bladder scanner) can reliably locate the heart when applied over the intercostal spaces of the anterior thorax in supine patients.  Conclusions In this cross-sectional study of healthy volunteers, an easy-to-use ultrasound device (bladder scanner) was able to reliably localize the heart. 
ultrasound device