Frequency and intensity of pulmonary bone marrow and fat embolism due to manual or automated chest compressions during cardiopulmonary resuscitation

Iatrogenic consequences of cardiopulmonary resuscitation (CPR) include sternal or rib fractures, pulmonary bone marrow embolisms (BME) and fat embolisms (FE). This report aimed to analyze the frequency and intensity of pulmonary BME and FE in fatal cases receiving final CPR efforts with the use of automated chest compression devices (ACCD) or manual chest compressions (mCC). The study cohort (all cardiac causes of death, no ante-mortem fractures) consisted of 15 cases for each group ACCD', mCC' and no CPR'. Lung tissue samples were retrieved and stained with hematoxylin eosin (n=4 each) and Sudan III (n=2 each). Evaluation was conducted microscopically for any existence of BME or FE, the frequency of BME-positive vessels, vessel size for BME and the graduation according to Falzi for FE. The data were compared statistically using non-parametric analyses. All groups were matched except for CPR duration (ACCD > mCC) but this time interval was linked to the existence of pulmonary BME (p=0.031). Both entities occur in less than 25% of all cases following unsuccessful CPR. BME was only detectable in CPR cases, but was similar between ACCD and mCC cases for BME frequency (p=0.666), BME intensity (p=0.857) and the size of BME-affected pulmonary vessels (p=0.075). If any, only mild pulmonary FE (grade I) was diagnosed without differences in the CPR method (p=0.624). There was a significant correlation between existence of BME and FE (p=0.043). Given the frequency, intensity and size of pulmonary BME and FE following CPR, these conditions may unlikely be considered as causative for death in case of initial survival but can be found in lower frequencies in autopsy histology.