Post-resuscitation pneumothorax – an underestimated complication?

Abstract

Background Pneumothorax can arise as an adverse effect of cardiopulmonary resuscitation (CPR) and could pose a potentially life-threatening complication. In two separate study projects we sought to investigate the incidence of pneumothorax both in clinical patients experiencing out-of-hospital cardiac arrest (OHCA) and cadavers embalmed by the Thiel method undergoing simulated cardiopulmonary resuscitation. Moreover, in the clinical study the identification of possible risk factors for development of pneumothorax following CPR and its association with outcomes were of particular interest. Methods The clinical trial was conducted as a retrospective analysis of hospitalized OHCA cases from 03/2014 until 12/2021 to which teams of the physician-staffed ambulance based at the University Medical centre of Graz, Austria responded. The dataset was compiled in accordance with the latest Utstein style recommendations. Chest imaging after hospital admission was reviewed to evaluate whether pneumothorax was present or not. Logistic regression analysis was then performed to identify risk factors for development of pneumothorax and assess its relationship with survival to hospital discharge and neurological outcome. In an experimental study design, eleven Thiel-embalmed cadavers underwent simulated cardiopulmonary resuscitation using a mechanical chest compression device and mechanical ventilators. After initial lung recruitment and following every two-minute cycle of chest compressions bilateral lung ultrasound was performed to test for pneumothorax. At the conclusion of the protocol, bilateral finger thoracostomy was conducted to assess for tension pneumothorax, indicated by a noticeable escape of air. Results In the clinical trial we were able to include 237 patients hospitalized after OHCA. In 26 patients (11.0%) pneumothorax was present after admission. History of obstructive pulmonary was significantly associated with post-CPR pneumothorax, with an incidence of 23.0% in this subgroup. Pneumothorax was not identified as a relevant factor to predict outcome. We detected pneumothorax in 8 out 11 (72.7%) Thiel cadavers at various stages of the study protocol. Pneumothorax was present unilaterally in 4 cases, while the remaining 4 cases showed bilateral tension pneumothorax. Higher recruitment pressure (35cmH2O instead of 30cmH2O) was found to be significantly (p=0.024) associated with the development of tension pneumothorax. Conclusion Pneumothorax after cardiopulmonary resuscitation is not an uncommon finding, occurring in more than one out of ten patients after out-of-hospital cardiac arrest. History of obstructive pulmonary disease seems to be a relevant risk factor for development of post-CPR pneumothorax. In the Thiel cadaver model of simulated CPR, pneumothorax was observed with notably greater frequency than in clinical cases. Recruitment pressure emerged as a key factor influencing its development and should be carefully considered in the design of future CPR studies utilizing Thiel-embalmed cadavers.

Datum der Bewilligung	2025
Originalsprache	Englisch
Gradverleihende Hochschule	Medizinische Universität Graz
Betreuer/-in	Stefan Heschl (Betreuer*in), Gerhard Prause (Betreuer*in) & Freyja-Maria Smolle-Juettner (Betreuer*in)