Safety with Mechanical Chest Compressions in CPR : Clinical studies with the LUCAS™ device

Chest compressions in cardiopulmonary resuscitation are of utmost importance although not without a risk. Many injuries are described but the incidence of these is hard to define due to methodological differences. It is strenuous to perform chest compressions and therefore mechanical chest compressions have been looked upon with interest. This thesis presents new insights on the panorama and incidence of injuries in modern CPR and a comparison of safety and efficacy between manual chest compressions and mechanical chest compressions with the LUCAS™ device. We also evaluated if computed tomography could be an aid in the detection of these injuries. Two pilot trials were conducted and one presented no difference in early survival with 26% and 31% having return of spontaneous circulation when comparing manual chest compressions with the LUCAS device in out-of-hospital cardiac arrest. The other revealed no difference in autopsy-detected injuries. A third multicentre autopsy trial revealed that in patients treated with manual chest compressions 78.3% had at least one injury and 63.9% had at least one rib fracture. The corresponding numbers for patients treated with the LUCAS device was 92.8% (p = 0.002) and 77.7% (p=0.022). Sternal fractures occurred in 54.2% and in 58.3% of the cases treated with manual chest compressions and the LUCAS device respectively (p = 0.556). The median number of rib fractures was 7 in the group receiving manual chest compressions and 6 in the group receiving chest compressions with the LUCAS device. In 31 cases a computed tomography was conducted prior to autopsy and we found a very strong correlation in the discrimination of patients with or without rib fractures (kappa=0.83). Mean difference between the two methods in detecting rib fractures was 0.16. The detection of other injuries did not have a strong correlation. In conclusion there is no difference in early survival between the two methods and mechanical chest compressions adds 14-15% more patients with rib fractures but the amount of rib fractures, sternal fractures and other injuries is equal. CT can aid but not replace autopsies in the detection of these injuries