Low bone mineral density increases the risk of multiple rib and sternal fractures during cardiopulmonary resuscitation.

Abstract

The correlation between low bone mineral density (BMD) and an increased risk of skeletal fractures is well-established. Rib and sternal fractures are common following cardiopulmonary resuscitation (CPR). However, it is unclear to what extent BMD corelates to the risk of rib and sternal fractures following CPR. The study aims to identify how BMD and different CPR modalities for chest compression (CC) (bystander, professionals, mechanical) are risk factors for rib and sternal fractures in a forensic autopsy population. Postmortem computed tomography (PMCT) was used for volumetric BMD estimation. All cases were retrieved from a database of cases referred for medicolegal autopsy, who had received antemortem CPR. The number of rib and sternal fractures across CC-modalities and BMD-groups were compared using negative binomial regressions models, while the frequency of rib and sternal fractures was compared with Fisher's Exact Test. The data revealed a higher frequency and number of rib and sternal fractures (fracture count (FC)) among cases with low BMD, regardless of age (BMD-osteopenia FC-ratio: 1.3 (1.0-1.6), BMD-osteoporotic: FC-ratio: 1.4 (1.0-1.9), compared to BMD-normal). In general, the frequency and number of rib and sternal fractures was the same across CC-modalities. A tendency towards lowest frequency and number of rib and sternal fractures was observed among bystander CC (Bystander frequency: 43 % and FC-mean: 5.3 (3.1-9.3) vs. other CC-modality where frequency and FC-mean were at least 76 % and 7.2 (5.3-9.7)). In cases with normal BMD, the addition of mechanical chest compression statistically significantly increased the frequency of rib and sternal fractures (Manual: 63.3 % vs. Manual + Mechanical: 88.0 %, Fisher's Exact Test: 0.021). The study identified a statistically significant correlation between low BMD and a higher number of rib and sternal fractures after CPR. Further, in cases with normal BMD, the use of mechanical CC increased the frequency of rib and sternal fractures.