Head Up Cardiopulmonary Resuscitation: Novel Physiological Discoveries and Latest Clinical Outcomes

Despite decades of research, survival rates following cardiac arrest remain dismal. The recent use of pressure-volume (PV) loop analysis has provided important insights into the underlying physiology of cardiopulmonary resuscitation (CPR). During conventional CPR (C-CPR), ventricular ejection is limited, contributing to poor circulatory effectiveness. In contrast, automated head-up CPR (AHUP-CPR)-which combines active compression-decompression (ACD) CPR, an impedance threshold device (ITD), and controlled head-thorax elevation-generates favorable negative intrathoracic pressure, promoting cerebral venous drainage and increases right heart preload, resulting in enhanced stroke volume, cardiac output, and end-tidal CO₂ (ETCO₂) by improving ventricular-pulmonary-arterial circulation. This article summarizes recent advances related to AHUP-CPR with a focus on novel physiological findings derived from intraventricular conductance catheter recordings during ventricular fibrillation, C-CPR, and AHUP-CPR. The PV loop observations shed new light on the mechanisms through which AHUP-CPR improves circulatory efficiency and neurological outcomes.