LETTER TO THE EDITOR

Active compression–decompression CPR necessitates follow-up post mortem

The study of thoracic injuries and biomechanics during CPR requires detailed studies that are very scarce. The role of the heart in CPR biomechanics has not been determined. This study aimed to determine the risk factors importance for serious ribcage damage due to CPR.

Data were collected from a prospective registry of out-of-hospital cardiac arrest between April 2014 and April 2017. This study included consecutive out-of-hospital CPR attempts undergoing an autopsy study focused on CPR injuries. Cardiac mass ratio was defined as the ratio of real to expected heart mass. Pearson’s correlation coefficient was used to select clinically relevant variables and subsequently classification tree models were built. The Gini index was used to determine the importance of the associated serious ribcage damage factors. The LUCAS® chest compressions device forces and the cardiac mass were analyzed by linear regression.

Two hundred CPR attempts were included (133 manual CPR and 67 mechanical CPR). The mean age of the sample was 60.4 ± 13.5, and 56 (28%) were women. In all, 65.0% of the patients presented serious ribcage damage. From the classification tree build with the clinically relevant variables, age (0.44), cardiac mass ratio (0.26), CPR time (0.22), and mechanical CPR (0.07), in that order, were the most influential factors on serious ribcage damage. The chest compression forces were greater in subjects with higher cardiac mass.

The heart plays a key role in CPR biomechanics being cardiac mass ratio the second most important risk factor for CPR injuries.

Summarise the evidence regarding the safety of mechanical and manual chest compressions for cardiac arrest patients.

Two investigators separately screened the articles of EMBASE, PubMed, and Cochrane Central databases. Cohort studies and randomized clinical trials (RCTs) that evaluated the safety of mechanical (LUCAS or AutoPulse) and manual chest compressions in cardiac arrest patients were included. A meta-analysis was performed using a random effects model to calculate the pooled odds ratios (ORs) and their 95% confidence intervals (CIs). The primary outcome was the rate of overall compression-induced injuries. The secondary outcomes included the incidence of life-threatening injuries, skeletal fractures, visceral injuries, and other soft tissue injuries.

The meta-analysis included 11 trials involving 2,818 patients. A significantly higher rate of overall compression-induced injuries was found for mechanical compressions than manual compressions (OR, 1.29; 95% CI, 1.19–1.41), while there was no significant difference between the two groups in respect of the rate of life-threatening injuries. Furthermore, both modalities shared similar incidences of sternal fractures, vertebral fractures, lung, spleen, and kidney injuries. However, compared to mechanical compressions, manual compressions were shown to present a reduced risk of posterior rib fractures, and heart and liver lesions.

The findings suggested that manual compressions could decrease the risk of compression-induced injuries compared to mechanical compressions in cardiac arrest patients. Interestingly, mechanical compressions have not increased the risk of life-threatening injuries, whereas additional high-quality RCTs are needed to further verify the safety of mechanical chest devices.

Trial registry: INPLASY; Registration number: INPLASY2020110111; URL: https://inplasy.com/.

The aim of this study was to compare the injuries observed after cardiopulmonary resuscitation (₁ CPR) by means of standard or assisted chest compression by the Lund University Cardiopulmonary Assist System (₂ LUCAS™2) device visualized by post-mortem computed tomography (₃ PMCT).

A retrospective study was conducted that included 44 cases delivered to our institution following CPR before death. All bodies underwent PMCT. The case group was divided into two groups: one group that underwent manual and one group that underwent mechanical CPR with the LUCAS™2 device. The main traumatic findings associated with CPR were reported, and a statistical evaluation was performed.

The LUCAS group comprised 24 cases, the manual group 20 cases. Rib fractures were the most frequent injury in both groups. A mean of 10.38 rib fractures per case was observed in the LUCAS group, and 10.40 fractures were observed in the manual group (p=0.999). Subcutaneous pre-sternal hematomas were described in 15/24 patients in the LUCAS group and in 6/20 patients in the manual group. The frequency of sternal factures was similar in both groups. A few trauma injuries to internal organs (i.e., retrosternal, perihepatic, and retroperitoneal hematomas and lung contusion) were recorded in both groups.

PMCT is useful for evaluating injuries related to CPR. LUCAS™2-CPR has a greater association with subcutaneous pre-sternal hematomas than standard CPR. There is no further significant difference in the incidence of injuries between mechanical and manual chest compression. From a forensic point of view, it is important to identify CPR-related injuries.

The reported incidence of injuries due to cardiopulmonary resuscitation using manual chest compressions (manual CPR) varies greatly. Our aim was to elucidate the incidence of CPR-related injuries by manual chest compressions compared to mechanical chest compressions with the LUCAS device (mechanical CPR) in non-survivors after out-of-hospital cardiac arrest.

In this prospective multicentre trial, including 222 patients (83 manual CPR/139 mechanical CPR), autopsies were conducted after unsuccessful CPR and the results were evaluated according to a specified protocol.

Among the patients included, 75.9% in the manual CPR group and 91.4% in the mechanical CPR group (p = 0.002) displayed CPR-related injuries. Sternal fractures were present in 54.2% of the patients in the manual CPR group and in 58.3% in the mechanical CPR group (p = 0.56). Of the patients in the manual CPR group, there were 64.6% with at least one rib fracture versus 78.8% in the mechanical CPR group (p = 0.02). The median number of rib fractures among patients with rib fractures was 7 in the manual CPR group and 6 in the mechanical CPR group. No CPR-related injury was considered to be the cause of death.

In patients with unsuccessful CPR after out-of-hospital cardiac arrest, rib fractures were more frequent after mechanical CPR but there was no difference in the incidence of sternal fractures. No injury was deemed fatal by the pathologist.

The incidence of thoracic injuries resulting from cardiopulmonary resuscitation (CPR) is not well characterized. We describe a case in which a CPR-associated atrial rupture was identified with ultrasound and successfully managed in the intensive care unit with a bedside thoracotomy and atrial repair. We then describe a systematic review with pooled data analysis of CPR-associated cardiovascular, pulmonary, pleural, and thoracic wall injuries.

PubMed, Scopus, EMBASE, and Web of Science were searched to identify relevant published studies. Unpublished studies were identified by searching the Australian and New Zealand Clinical Trials Registry, World Health Organization International Clinical Trials Registry Platform, Cochrane Library, ClinicalTrials.gov, Current Controlled Trials, and Google.

Inclusion criteria for the pooled analysis were any clinical or autopsy study in which (a) patients underwent cardiopulmonary resuscitation, (b) chest compressions were administered either manually or with the assistance of active compression–decompression devices, and (c) autopsy or dedicated imaging assessments were conducted to identify complications. Exclusion criteria for the pooled analysis were pre-clinical studies, case reports and abstracts.

Nine-hundred twenty-eight potentially relevant references were identified. Twenty-seven references met inclusion criteria.

A systematic review of the literature is provided with pooled data analysis.

The incidence of reported CPR-associated cardiovascular and thoracic wall injuries varies widely. CPR with active compression–decompression devices has a higher reported incidence of cardiopulmonary injuries. Bedside ultrasound may be a useful adjunct to assess and risk-stratify patients to identify serious or life-threatening CPR-associated injuries.