Frequency and intensity of pulmonary bone marrow and fat embolism due to manual or automated chest compressions during cardiopulmonary resuscitation

Iatrogenic consequences of cardiopulmonary resuscitation (CPR) include sternal or rib fractures, pulmonary bone marrow embolisms (BME) and fat embolisms (FE). This report aimed to analyze the frequency and intensity of pulmonary BME and FE in fatal cases receiving final CPR efforts with the use of automated chest compression devices (ACCD) or manual chest compressions (mCC). The study cohort (all cardiac causes of death, no ante-mortem fractures) consisted of 15 cases for each group 'ACCD', 'mCC' and 'no CPR'. Lung tissue samples were retrieved and stained with hematoxylin eosin (n = 4 each) and Sudan III (n = 2 each). Evaluation was conducted microscopically for any existence of BME or FE, the frequency of BME-positive vessels, vessel size for BME and the graduation according to Falzi for FE. The data were compared statistically using non-parametric analyses. All groups were matched except for CPR duration (ACCD > mCC) but this time interval was linked to the existence of pulmonary BME (p = 0.031). Both entities occur in less than 25% of all cases following unsuccessful CPR. BME was only detectable in CPR cases, but was similar between ACCD and mCC cases for BME frequency (p = 0.666), BME intensity (p = 0.857) and the size of BME-affected pulmonary vessels (p = 0.075). If any, only mild pulmonary FE (grade I) was diagnosed without differences in the CPR method (p = 0.624). There was a significant correlation between existence of BME and FE (p = 0.043). Given the frequency, intensity and size of pulmonary BME and FE following CPR, these conditions may unlikely be considered as causative for death in case of initial survival but can be found in lower frequencies in autopsy histology.

Chest compression-associated injuries in cardiac arrest patients treated with manual chest compressions versus automated chest compression devices (LUCAS II) - a forensic autopsy-based comparison

The aim of this autopsy study was to investigate chest-compression associated injuries to the trunk in out-of-hospital and in-hospital non-traumatic cardiac arrest patients treated with automated external chest compression devices (ACCD; all with LUCAS II devices) versus exclusive manual chest compressions (mCC). In this retrospective single-center study, all forensic autopsies between 2011 and 2017 were included. Injuries following cardiopulmonary resuscitation (CPR) in patients treated with mCC or ACCD were investigated and statistically compared using a bivariate logistic regression. In the seven-year period with 4433 autopsies, 614 were analyzed following CPR (mCC vs. ACCD: n = 501 vs. n = 113). The presence of any type of trunk injury was correlated with longer resuscitation intervals (30 ± 15 vs. 44 ± 25 min, p < 0.05). In comparison with mCC, treatment with ACCD led to more frequent skin emphysema (5 vs 0%, p = 0.012), pneumothorax (6 vs. 1%, p = 0.008), lung lesions (19 vs. 4%, p = 0.008), hemopericardium (3 vs 1%, p = 0.025) and liver lesions (10 vs. 1%, p = 0.001), all irrespective of confounding aspects. Higher age and longer CPR durations statistically influenced frequency of sternal and rib fractures (p < 0.001). The mean number of fractured ribs did not vary significantly between the groups (6 ± 3 vs. 7 ± 2, p = 0.09). In this cohort with unsuccessful CPR, chest compression-related injuries were more frequent following ACCD application than in the mCC group, but with only minutely increased odds ratios. The severity of injuries did not differ between the groups, and no iatrogenic injury was declared by the forensic pathologist as being fatal. In the clinical routine after successful return of spontaneous circulation a computed tomography scan for CPR-associated injuries is recommended as soon as possible.

Use of automated chest compression devices after out-of-hospital cardiac arrest in Sweden

OBJECTIVE

To evaluate the implementation of automated chest compression cardiopulmonary resuscitation (ACC-CPR) after out-of-hospital cardiac arrest (OHCA) in Sweden during the years 2011 through 2015. The association between ACC-CPR and 30-day survival was studied as a secondary objective.

METHODS

The Swedish cardiopulmonary resuscitation registry is a prospectively recorded nationwide registry of modified Utstein parameters including all patients with attempted resuscitation after OHCA. Propensity score matching (PSM) was used to adjust for known confounders in the secondary analysis.

RESULTS

Of the 24,316 patients included in the study population, 32.4% received ACC-CPR, with substantial regional variation ranging from 0.8% to 78.8%. Male gender and an initial shockable rhythm were associated with ACC-CPR, whereas crew witnessed status was associated with manual CPR. Potential markers of prolonged resuscitation attempts (drug administration and endotracheal intubation) were more prevalent in the ACC-CPR group. The unadjusted 30-day survival rate was 6.3% for ACC-CPR patients. The adjusted odds ratio for 30-day survival regarding use of an ACC device was 0.72 (95% CI 0.62-0.84, p<0.001, n=13922).

CONCLUSION

The use of ACC devices varied significantly between Swedish regions and overall survival to 30days was low among patients receiving ACC-CPR. Although measured and unmeasured confounding might explain our finding of lower survival rates for patients exposed to ACC-CPR, specific guidelines recommending when and how ACC-CPR should be used are warranted as there might be circumstances where these devices do more harm than good.