Changes in temporal muscle dimensions and their clinical impact in out-of-hospital cardiac arrest survivors

•Significant decreases in temporal muscle dimensions observed in OHCA survivors.•The median daily rate for temporal muscle area atrophy was 2.0% per day.•No correlation found between temporal muscle atrophy and 30-day survival.•Clinical factors did not show a significant link with temporal muscle atrophy. This study investigates temporal muscle atrophy in out-of-hospital cardiac arrest patients post-resuscitation, seeking associations with neurological outcomes and factors associated with atrophy. Using data from six Japanese intensive care units, adult patients’ post-resuscitation who underwent head computed tomography scans on admission and two to five days post-admission were assessed. Temporal muscle area, thickness, and density were quantified from a single cross-sectional image. Patients were categorized into 'atrophy' or 'no atrophy' groups based on median daily temporal muscle atrophy rates. The primary outcome was changes in temporal muscle dimensions between admission and follow-up two to five days later. Secondary outcomes included assessing the impact of temporal muscle atrophy on 30-day survival, as well as identifying any clinical factors associated with temporal muscle atrophy. A total of 185 patients were analyzed. Measurements at follow-up revealed significant decreases in temporal muscle area (214 vs. 191 mm2, p