Association of Multiple Rib Fractures With Pneumonia After Successful Cardiopulmonary Resuscitation: A Retrospective Cohort Study Using Propensity Score Matching

Abstract Background: Few studies have examined the impact of chest wall injury on respiratory complications after cardiopulmonary resuscitation. This is due to many confounding factors for the development of complications after cardiopulmonary resuscitation. Accordingly, we investigated the association between multiple rib fractures and the incidence of pneumonia during the post-resuscitation period after adjusting for confounding factors using a propensity score.Methods: This single-centre, retrospective cohort study enrolled adult, non-traumatic, out-of-hospital, cardiac arrest patients who maintained circulation for >48 h between June 2015 and May 2019. Rib fractures were evaluated by computed tomography on the day of hospital admission, and the association with newly developed pneumonia within 7 days of hospitalisation was analysed using propensity score matching with adjustment for variables previously reported to be risk factors for the development of pneumonia.Results: Of the 683 out-of-hospital cardiac arrest patients treated during the study period, 87 eligible cases were enrolled for analysis. Thirty-two patients had multiple rib fractures identified by computed tomography and 35 patients developed pneumonia. The presence of multiple rib fractures was significantly associated with a higher incidence of pneumonia (propensity score-adjusted hazard ratio: 3.51; 95% confidence interval: 1.59–7.72; p=0.002). Consistently, after propensity score matching, the multiple rib fracture group showed significantly shorter pneumonia-free survival than the non-multiple rib fracture group (p<0.01).Conclusion: Multiple rib fractures are independently associated with the development of pneumonia after successful resuscitation.