Thicker Posterior Subcutaneous Adipose Tissue (SAT) During Peri-arrest Period is Associated Favorable Neurological Outcome at Hospital Discharge in Patients Achieving Return of Spontaneous Circulation (ROSC) After IHCA: an Observational Study

Background: Moderate overweight in hospital cardiac arrest (IHCA) patients tend to have better neurological outcomes after attaining return of spontaneous circulation (ROSC), but the underlying mechanism has not been elucidated. Method: We collected the demographics, clinical and cardiac arrest characteristics, thoracic cage dimension indexes measured from computed tomography (CT) images, and survival and neurological outcome at hospital discharge of the eligible patients. Patients receiving different kind of respiratory support while performing pre-compression and post-compression CT scans were divided into groups and we did the subgroup analysis. Results: We reviewed the clinical records of 1663 CA patients. After selection, 70 patients were included into this study. We found thicker posterior SAT (pSAT) at the 7/8/10/11 spinous process plane in patients with favorable neurological outcome in post-compression CT images(p<0.05). For patients with favorable neurological outcome receiving one kind of respiratory support during peri-cardiac arrest period, we found significantly thicker pSAT at the 6/7/8/9/10/11 spinous process plane in pre-compression and 7/8/9/10/11/12 spinous plane in post-compression CT images (p<0.05). Patients with favorable neurological outcome receiving mechanical ventilation (MV) in peri-cardiac arrest period had thicker pSAT at the 10/11/12 spinous process plane; for those without MV, thicker pSATs were found at 10/11 spinous process plane in post-compression CT images(p<0.05). We found no difference in bony thorax within different vertebral plane after subgroup analysis (p>0.05). Conclusion: Thicker posterior SAT depth during peri-cardiac arrest period is associated with favorable neurological outcome at discharge for IHCA survivors. This could partly explain the “obese paradox” that overweight patients have better prognosis after CA. We recommend a multiple vertebral plane thorax measurement for future investigations concerning chest characteristics.