Cardiac arrest, stony heart, and cardiopulmonary resuscitation: An updated revisit

The post-resuscitation period is recognized as the main predictor of cardiopul-monary resuscitation(CPR)outcomes.The first description of post-resuscitation syndrome and stony heart was published over 50 years ago.Major manifestations may include but are not limited to,persistent precipitating pathology,systemic ischemia/reperfusion response,post-cardiac arrest brain injury,and finally,post-cardiac arrest myocardial dysfunction(PAMD)after successful resuscitation.Why do some patients initially survive successful resuscitation,and others do not?Also,why does the myocardium response vary after resuscitation?These ques-tions have kept scientists busy for several decades since the first successful resuscitation was described.By modifying the conventional modalities of resu-scitation together with new promising agents,rescuers will be able to salvage the jeopardized post-resuscitation myocardium and prevent its progression to a dismal,stony heart.Community awareness and staff education are crucial for shortening the resuscitation time and improving short-and long-term outcomes.Awareness of these components before and early after the restoration of circulation will enhance the resuscitation outcomes.This review extensively addresses the underlying pathophysiology,management,and outcomes of post-resuscitation syndrome.The pattern,management,and outcome of PAMD and post-cardiac arrest shock are different based on many factors,including in-hospital cardiac arrest vs out-of-hospital cardiac arrest(OHCA),witnessed vs unwitnessed cardiac arrest,the underlying cause of arrest,the duration,and protocol used for CPR.Although restoring spontaneous circulation is a vital sign,it should not be the end of the game or lone primary outcome;it calls for better understanding and aggressive multi-disciplinary interventions and care.The development of stony heart post-CPR and OHCA remain the main challenges in emergency and critical care medicine.

Successful rescue of disseminated Nocardia infection with multiple abscesses in a patient with membranous nephropathy after cardiopulmonary resuscitation:A three-year follow-up

Nocardiosis manifests as an opportunistic infection,primarily affecting individuals who are immunocompromised and susceptible to the infection.We present a case study of one patient with nephrotic syndrome and membranous nephropathy,who underwent treatment with prednisone and cyclosporine in 2016.In early 2017,the patient was diagnosed with a"fungal infection"and discontinued the use of cyclosporine.After one month of anti-infection therapy,a cranial magnetic resonance imaging scan showed multiple abscesses in the right temporal region.The diagnosis of nocardiosis was confirmed based on the presence of metastatic abscess masses,multiple lung and brain lesions,and a positive culture of Nocardia in the drainage.We changed the anti-infection therapy to a combination of trimethoprim-sulfamethoxazole(TMP-SMX),minocycline,and voriconazole.However,the patient experienced a sudden cardiac arrest and subsequently recovered after cardiopulmonary resuscitation.During the five-month follow-up period following the discharge,the patient displayed an enhanced nutritional status and stable renal function.The focal infection ultimately resolved during the subsequent three years.Neuro-infection caused by Nocardia should be considered in immunocompromised patients,and TMP-SMX is the preferred initial therapy;however,because of the high mortality rate,a long-term combination therapy with imipenem,cefotaxime,amikacin,and TMP-SMX is suggested.

Advances in the Use of Prone Cardiopulmonary Resuscitation During Spinal Surgery in the Prone Position

Spinal surgery is usually performed in the prone position, which is a longer and more difficult procedure and is prone to complications such as circulatory dysfunction and stress injuries. Among them, stress injury is the main complication of prone spine surgery, but the reasons for stress injury in prone spine surgery are not clear, and whether prone cardiopulmonary resuscitation (CPR) can be used needs to be further verified. Supine cardiopulmonary resuscitation is commonly used in posterior spinal surgery, retroperitoneal surgery, and so on, which can effectively improve the patient’s hypoxemia. Such surgeries require a high level of anesthetic management, and cardiopulmonary resuscitation is necessary if a patient in a prone position experiences cardiac arrest. In the process of cardiopulmonary resuscitation, supine cardiopulmonary resuscitation is often used, especially for some obese patients, if they are immediately changed to the supine position, it takes up more time, there may be wound infection, and there is a possibility of missing the optimal rescue and resuscitation time. Based on this, this paper reviews the use of prone-position cardiopulmonary resuscitation for spinal surgery in the prone position.

Analysis of the Application Value of Virtual Reality Combined with Flipped Classroom Teaching Mode in Cardiopulmonary Resuscitation Teaching

Objective:To analyze the value of using virtual reality combined with the flipped classroom teaching model in teaching cardiopulmonary resuscitation(CPR).Methods:Two classes of our nursing program were randomly selected for the study from September 2022 to September 2023,Class A(52 students,conventional teaching method)and Class B(52 students,virtual reality combined with flipped classroom teaching mode).The assessment scores and independent learning ability scores of the students in the two classes were compared.Results:CPR theory and operation scores,passing rate,and independent learning ability scores of Class B were higher than those of Class A(P<0.05).Conclusion:the use of virtual reality combined with the flipped classroom teaching mode in CPR teaching is conducive to the improvement of students’assessment scores and independent learning ability.

Correction:Establishment of a prediction model for prehospital return of spontaneous circulation in out-of-hospital patients with cardiac arrest

This is an erratum to an already published paper named“Establishment of a prediction model for prehospital return of spontaneous circulation in out-ofhospital patients with cardiac arrest”.We found errors in the affiliated institution of the authors.We apologize for our unintentional mistake.Please note,these changes do not affect our results.

The neuro-prognostic value of the ion shift index in cardiac arrest patients following extracorporeal cardiopulmonary resuscitation

BACKGROUND:The ion shift index(ISI) as a prognostic indicator that can show the severity of hypoxic-ischemic injury.We aimed to evaluate the performance of the ISI in predicting unfavorable neurological outcomes at hospital discharge in cardiac arrest(CA) patients following extracorporeal cardiopulmonary resuscitation(ECPR) and to compare its performance to other prognostic predictors.METHODS:This was a retrospective observational study including adult CA patients treated with ECPR between January 2018 and December 2022 in a tertiary hospital.Data regarding clinical characteristics and laboratory parameters were collected from medical records.The ISI was determined based on the first available serum electrolyte levels after ECPR.The primary outcome was unfavorable neurological status at hospital discharge,defined as Cerebral Performance Categories 3–5.Comparisons of the characteristics between the two groups were made using the χ2 test for categorical variables and the t-test or non-parametric Mann-Whitney U-test for continuous variables,as appropriate.Correlation analysis was performed using Spearman’s rank correlation coeficient.A two-tailed P-value <0.05 was considered statistically significant.RESULTS:Among the 122 patients involved,46(37.7%) had out-of-hospital CA,and 88 had unfavorable neurological outcomes.The ISI was significantly higher in the unfavorable outcome group than in the favorable outcome group(3.74 [3.15–4.57] vs.2.69 [2.51–3.07],P<0.001).A higher ISI level was independently related to unfavorable outcome(odds ratio=6.529,95% confidence interval 2.239–19.044,P=0.001).An ISI level >3.12 predicted unfavorable outcomes with a sensitivity and specificity of 74.6% and 85.2%,respectively(P<0.001).The prognostic performance of ISI(area under the curve [AUC]=0.887) was similar to that of other predictors,such as gray-to-white matter ratio(AUC=0.850,P=0.433) and neuronspecific enolase(AUC=0.925,P=0.394).CONCLUSION:ISI may be used as a prognostic biomarker to predict neurological outcomes in CA patients following ECPR.

Vagus nerve stimulation protects against cerebral injury after cardiopulmonary resuscitation by inhibiting inflammation through the TLR4/NF-κB and α7nAChR/JAK2 signaling pathways

BACKGROUND: Our previous research proved that vagus nerve stimulation(VNS) improved the neurological outcome after cardiopulmonary resuscitation(CPR) by activating α7 nicotinic acetylcholine receptor(α7nAChR) in a rat model, but the underlying mechanism of VNS in neuroprotection after CPR remains unclear.METHODS: In vivo, we established a mouse model of cardiac arrest(CA)/CPR to observe the survival rate, and the changes in inflammatory factors and brain tissue after VNS treatment. In vitro, we examined the effects of α7nAChR agonist on ischemia/reperfusion(I/R)-induced inflammation in BV2 cells under oxygen-glucose deprivation/reoxygenation(OGD/R) conditions. We observed the changes in cell survival rate, the levels of inflammatory factors, and the expressions of α7nAChR/Janus kinase 2(JAK2) and toll-like receptor 4(TLR4)/nuclear factor-κB(NF-κB).RESULTS: In vivo, VNS preconditioning enhanced functional recovery, improved the survival rate, and reduced hippocampal CA1 cell damage, and the levels of inflammatory mediators after CA/CPR. The application of α7nAChR agonists provided similar effects against cerebral injury after the return of spontaneous circulation(ROSC), while α7nAChR antagonists reversed these neuroprotective impacts. The in vitro results mostly matched the findings in vivo. OGD/R increased the expression of tumor necrosis factor-alpha(TNF-α), TLR4 and NF-κB p65. When nicotine was added to the OGD/R model, the expression of TLR4, NF-κB p65, and TNF-α decreased, while the phosphorylation of JAK2 increased, which was prevented by preconditioning with α7nAChR or JAK2 antagonists.CONCLUSION: The neuroprotective effect of VNS correlated with the activation of α7nAChR. VNS may alleviate cerebral IR injury by inhibiting TLR4/NF-κB and activating the α7nAChR/JAK2 signaling pathway.

Cardiac arrest and cardiopulmonary resuscitation in“hostile”environments:Using automated compression devices to minimize the rescuers’danger

Mechanical automated compression devices are being used in cardiopulmonary resuscitation instead of manual,“hands-on”,rescuer-delivered chest compressions.The-theoretical-advantages include high-quality non-stop compressions,thus freeing the rescuer performing the compressions and additionally the ability of the rescuer to stand reasonably away from a potentially“hazardous”victim,or from hazardous and/or difficult resuscitation conditions.Such circumstances involve cardiopulmonary resuscitation(CPR)in the Cardiac Catheterization Laboratory,especially directly under the fluoroscopy panel,where radiation is well known to cause detrimental effects to the rescuer,and CPR during/after land or air transportation of cardiac arrest victims.Lastly,CPR in a coronavirus disease 2019 patient/ward,where the danger of contamination and further serious illness of the health provider is very existent.The scope of this review is to review and present literature and current guidelines regarding the use of mechanical compressions in these“hostile”and dangerous settings,while comparing them to manual compressions.

Establishment of a Rat Model of Capillary Leakage Syndrome Induced by Cardiopulmonary Resuscitation After Cardiac Arrest

Objective:Cardiopulmonary resuscitation(CPR)after cardiac arrest(CA)is one of the main causes of capillary leakage syndrome(CLS).This study aimed to establish a stable CLS model following the CA and cardiopulmonary resuscitation(CA-CPR)model in Sprague-Dawley(SD)rats.Methods:We conducted a prospective,randomized,animal model study.All adult male SD rats were randomly divided into a normal group(group N),a sham operation group(group S),and a cardiopulmonary resuscitation group(group T).The SD rats of the three groups were all inserted with 24-G needles through their left femoral arteries and right femoral veins.In group S and group T,the endotracheal tube was intubated.In group T,CA induced by asphyxia(AACA)was caused by vecuronium bromide with the endotracheal tube obstructed for 8 min,and the rats were resuscitated with manual chest compression and mechanical ventilation.Preresuscitation and postresuscitation measurements,including basic vital signs(BVS),blood gas analysis(BG),routine complete blood count(CBC),wet-to-dry ratio of tissues(W/D),and the HE staining results after 6 h were evaluated.Results:In group T,the success rate of the CA-CPR model was 60%(18/30),and CLS occurred in 26.6%(8/30)of the rats.There were no significant differences in the baseline characteristics,including BVS,BG,and CBC,among the three groups(P>0.05).Compared with pre-asphyxia,there were significant differences in BVS,CBC,and BG,including temperature,oxygen saturation(SpO_(2)),mean arterial pressure(MAP),central venous pressure(CVP),white blood cell count(WBC),hemoglobin,hematocrit,pH,pCO_(2),pO_(2),SO_(2),lactate(Lac),base excess(BE),and Na+(P<0.05)after the return of spontaneous circulation(ROSC)in group T.At 6 h after ROSC in group T and at 6 h after surgery in groups N and S,there were significant differences in temperature,heart rate(HR),respiratory rate(RR),SpO_(2),MAP,CVP,WBC,pH,pCO_(2),Na+,and K+among the three groups(P<0.05).Compared with the other two groups,the rats in group T showed a significantly increased W/D weight ratio(P<0.05).The HE-stained sections showed consistent severe lesions in the lung,small intestine,and brain tissues of the rats at 6 h after ROSC following AACA.Conclusion:The CA-CPR model in SD rats induced by asphyxia could reproduce CLS with good stability and reproducibility.

Do cardiopulmonary resuscitation real-time audiovisual feedback devices improve patient outcomes? A systematic review and metaanalysis

BACKGROUND Cardiac arrest is a leading cause of mortality in America and has increased in the incidence of cases over the last several years.Cardiopulmonary resuscitation(CPR)increases survival outcomes in cases of cardiac arrest;however,healthcare workers often do not perform CPR within recommended guidelines.Real-time audiovisual feedback(RTAVF)devices improve the quality of CPR performed.This systematic review and meta-analysis aims to compare the effect of RTAVF-assisted CPR with conventional CPR and to evaluate whether the use of these devices improved outcomes in both in-hospital cardiac arrest(IHCA)and out-of-hospital cardiac arrest(OHCA)patients.AIM To identify the effect of RTAVF-assisted CPR on patient outcomes and CPR quality with in-and OHCA.METHODS We searched PubMed,SCOPUS,the Cochrane Library,and EMBASE from inception to July 27,2020,for studies comparing patient outcomes and/or CPR quality metrics between RTAVF-assisted CPR and conventional CPR in cases of IHCA or OHCA.The primary outcomes of interest were return of spontaneous circulation(ROSC)and survival to hospital discharge(SHD),with secondary outcomes of chest compression rate and chest compression depth.The methodo-logical quality of the included studies was assessed using the Newcastle-Ottawa scale and Cochrane Collaboration’s“risk of bias”tool.Data was analyzed using R statistical software 4.2.0.results were statistically significant if P<0.05.RESULTS Thirteen studies(n=17600)were included.Patients were on average 69±17.5 years old,with 7022(39.8%)female patients.Overall pooled ROSC in patients in this study was 37%(95%confidence interval=23%-54%).RTAVF-assisted CPR significantly improved ROSC,both overall[risk ratio(RR)1.17(1.001-1.362);P=0.048]and in cases of IHCA[RR 1.36(1.06-1.80);P=0.002].There was no significant improvement in ROSC for OHCA(RR 1.04;0.91-1.19;P=0.47).No significant effect was seen in SHD[RR 1.04(0.91-1.19);P=0.47]or chest compression rate[standardized mean difference(SMD)-2.1;(-4.6-0.5);P=0.09].A significant improvement was seen in chest compression depth[SMD 1.6;(0.02-3.1);P=0.047].CONCLUSION RTAVF-assisted CPR increases ROSC in cases of IHCA and chest compression depth but has no significant effect on ROSC in cases of OHCA,SHD,or chest compression rate.

Cardiac arrest secondary to pulmonary embolism treated with extracorporeal cardiopulmonary resuscitation:Six case reports

BACKGROUND Massive pulmonary embolism(PE)results in extremely high mortality rates.Veno-arterial extracorporeal membrane oxygenation(VA-ECMO)can provide circulatory and oxygenation support and rescue patients with massive PE.However,there are relatively few studies of extracorporeal cardiopulmonary resuscitation(ECPR)in patients with cardiac arrest(CA)secondary to PE.The aim of the present study is to investigate the clinical use of ECPR in conjunction with heparin anticoagulation in patients with CA secondary to PE.CASE SUMMARY We report the cases of six patients with CA secondary to PE treated with ECPR in the intensive care unit of our hospital between June 2020 and June 2022.All six patients experienced witnessed CA whilst in hospital.They had acute onset of severe respiratory distress,hypoxia,and shock rapidly followed by CA and were immediately given cardiopulmonary resuscitation and adjunctive VA-ECMO therapy.During hospitalization,pulmonary artery computed tomography angiography was performed to confirm the diagnosis of PE.Through anticoagulation management,mechanical ventilation,fluid management,and antibiotic treatment,five patients were successfully weaned from ECMO(83.33%),four patients survived for 30 d after discharge(66.67%),and two patients had good neurological outcomes(33.33%).CONCLUSION For patients with CA secondary to massive PE,ECPR in conjunction with heparin anticoagulation may improve outcomes.

Establishment of a prediction model for prehospital return of spontaneous circulation in out-of-hospital patients with cardiac arrest

BACKGROUND Out-of-hospital cardiac arrest(OHCA)is a leading cause of death worldwide.AIM To explore factors influencing prehospital return of spontaneous circulation(P-ROSC)in patients with OHCA and develop a nomogram prediction model.METHODS Clinical data of patients with OHCA in Shenzhen,China,from January 2012 to December 2019 were retrospectively analyzed.Least absolute shrinkage and selection operator(LASSO)regression and multivariate logistic regression were applied to select the optimal factors predicting P-ROSC in patients with OHCA.A nomogram prediction model was established based on these influencing factors.Discrimination and calibration were assessed using receiver operating charac-teristic(ROC)and calibration curves.Decision curve analysis(DCA)was used to evaluate the model’s clinical utility.RESULTS Among the included 2685 patients with OHCA,the P-ROSC incidence was 5.8%.LASSO and multivariate logistic regression analyses showed that age,bystander cardiopulmonary resuscitation(CPR),initial rhythm,CPR duration,ventilation mode,and pathogenesis were independent factors influencing P-ROSC in these patients.The area under the ROC was 0.963.The calibration plot demonstrated that the predicted P-ROSC model was concordant with the actual P-ROSC.The good clinical usability of the prediction model was confirmed using DCA.CONCLUSION The nomogram prediction model could effectively predict the probability of P-ROSC in patients with OHCA.

Changes of Tumor Necrosis Factor-α and the Effects of Ulinastatin Injection during Cardiopulmonary Cerebral Resuscitation

Summary: The changes of tumor necrosis factor-α (TNF-α) and brain ultrastructure during cardiopulmonary resuscitation and the effects of ulinastation injection were observed, and the mechanism was investigated. Twenty-four adult healthy Sprague-Dawley rats were randomly divided into control group (8 rats), resuscitation group (8 rats) and ulinastatin (UTI) group (8 rats). Rats in control group underwent tracheotomy without clipping the trachea to induce circulatory and respiratory standstill. Rats in resuscitation and ulinastatin group were subjected to the procedure of establishing the model of cardiopulmonary cerebral resuscitation (CPCR). Rats in ulinastatin group were given with UTI 104 U/kg once after CPCR. In the control group, the plasma was collected immediate, 30 min, 2 h, 4 h, and 6 h after tracheotomy. In resuscitation group and UTI group, plasma was collected immediate after tracheotomy, 30 min, 2 h, 4 h and 6 h after successful resuscitation. The plasma levels of TNF-α were determined by radioimmunoassay (RIA). At the end of the experiment, 2 rats were randomly selected from each group and were decapitated. The cortex of the brain was taken out immediately to observe the ultrastructure changes. In control group, there were no significant differences in the level of TNF-α among different time points (P>0.05). In resuscitation group, the level of TNF-α was increased obviously after resuscitation (P<0.01) and reached its peak 2 h later after resuscitation. An increasing trend of TNF-α showed in UTI group. There were no differences in TNF-α among each sample taken after successful resuscitation and that after tracheotomy. The utrastructure of brains showed the injury in UTI group was ameliorated as compared with that in resuscitation group. In early period of CPCR, TNF-α was expressed rapidly and kept increasing. It indicated that TNF-α might take part in the tissue injury after CPCR. The administration of UTI during CACR could depress TNF-α and ameliorate brain injury. By regulating the expression of damaging mediator, UTI might provide a protective effect on the tissue injury after CPCR.

Pre-recorded instructional audio vs. dispatchers' conversational assistance in telephone cardiopulmonary resuscitation: A randomized controlled simulation study

BACKGROUND:To assess the effectiveness of the telephone chest-compression-only cardiopulmonary resuscitation(CPR)guided by a pre-recorded instructional audio when compared with dispatcher-assisted resuscitation.METHODS:It was a prospective,blind,randomised controlled study involving 109 medical students without previous CPR training.In a standardized mannequin scenario,after the step of dispatcher-assisted cardiac arrest recognition,the participants performed compression-only resuscitation guided over the telephone by either:(1)the pre-recorded instructional audio(n=57);or(2)verbal dispatcher assistance(n=52).The simulation video records were reviewed to assess the CPR performance using a 13-item checklist.The interval from call reception to the first compression,total number and rate of compressions,total number and duration of pauses after the first compression were also recorded.RESULTS:There were no significant differences between the recording-assisted and dispatcher-assisted groups based on the overall performance score(5.6±2.2 vs.5.1±1.9,P>0.05)or individual criteria of the CPR performance checklist.The recording-assisted group demonstrated provided(170.2±48.0 vs.156.2±60.7).CONCLUSION:When provided by untrained persons in the simulated settings,the compression-only resuscitation guided by the pre-recorded instructional audio is no less efficient than dispatcher-assisted CPR.Future studies are warranted to further assess feasibility of using instructional audio aid as a potential alternative to dispatcher assistance.

Investigation of Myocardial Stunning after Cardiopulmonary Resuscitation in Pigs

Objective To investigate cardiac function and myocardial perfusion during 48 h after cardiopulmonary resuscitation （CPR）, further to test myocardial stunning and seek indicators for long‐term survival after CPR. Methods After 4 min of untreated ventricular fibrillation, fifteen anesthetized pigs were studied at baseline and 2 h, 4 h, 24 h, and 48 h after restoration of spontaneous circulation （ROSC）. Hemodynamic data, echocardiography and gated‐single photon emission computed tomography myocardial perfusion images were carried out. Results Mean arterial pressure （MAP）, coronary perfusion pressure （CPP） and cardiac troponin I （CTNI） showed significant differences between eventual survival animals and non‐survival animals at 4 h after ROSC （109.2±10.7 mmHg vs. 94.8±12.3 mmHg, P=0.048; 100.8±6.9 mmHg vs. 84.4±12.6 mmHg, P=0.011; 1.60±0.13 ug/L vs. 1.75±0.10 ug/L, P=0.046）. Mitral valve early‐to‐late diastolic peak velocity ratio, mitral valve deceleration time recovered 24 h; ejection faction and the summed rest score recovered 48 h after ROSC. Conclusion Cardiac systolic and early active relaxation dysfunctions were reversible within survival animals; cardiac stunning might be potentially adaptive and protective after CPR. The recovery of MAP, CPP, and CTNI could be the indicators for long‐term survival after CPR.

Comparison of extracorporeal and conventional cardiopulmonary resuscitation:A meta-analysis of 2 260 patients with cardiac arrest

BACKGROUND: This meta-analysis aimed to determine whether extracorporeal cardiopulmonary resuscitation(ECPR), compared with conventional cardiopulmonary resuscitation(CCPR), improves outcomes in adult patients with cardiac arrest(CA).DATA RESOURCES: Pub Med, EMBASE, Web of Science, and China Biological Medicine Database were searched for relevant articles. The baseline information and outcome data(survival, good neurological outcome at discharge, at 3–6 months, and at 1 year after CA) were collected and extracted by two authors. Pooled risk ratios(RRs) and 95% confidence intervals(CIs) were calculated using Review Manager 5.3.RESULTS: In six studies 2 260 patients were enrolled to study the survival rate to discharge and longterm neurological outcome published since 2000. A signi? cant effect of ECPR was observed on survival rate to discharge compared to CCPR in CA patients(RR 2.37, 95%CI 1.63–3.45, P<0.001), and patients who underwent ECPR had a better long-term neurological outcome than those who received CCPR(RR 2.79, 95%CI 1.96–3.97, P<0.001). In subgroup analysis, there was a significant difference in survival to discharge favoring ECPR over CCPR group in OHCA patients(RR 2.69, 95%CI 1.48–4.91, P=0.001). However, no signi? cant difference was found in IHCA patients(RR 1.84, 95%CI 0.91–3.73, P=0.09).CONCLUSION: ECPR showed a bene? cial effect on survival rate to discharge and long-term neurological outcome over CCPR in adult patients with CA.

Bone marrow-derived mesenchymal stem cell transplantation attenuates overexpression of inflammatory mediators in rat brain after cardiopulmonary resuscitation

Emerging evidence suggests that bone marrow-derived mesenchymal stem cell transplantation improves neurological function after cardiac arrest and cardiopulmonary resuscitation;however, the precise mechanisms remain unclear. This study aimed to investigate the effect of bone marrow-derived mesenchymal stem cell treatment on expression profiles of multiple cytokines in the brain after cardiac arrest and cardiopulmonary resuscitation. Cardiac arrest was induced in rats by asphyxia and cardiopulmonary resuscitation was initiated 6 minutes after cardiac arrest. One hour after successful cardiopulmonary resuscitation, rats were injected with either phosphate-buffered saline(control) or 1 × 10~6 bone marrow-derived mesenchymal stem cells via the tail vein. Serum S100 B levels were measured by enzyme-linked immunosorbent assay and neurological deficit scores were evaluated to assess brain damage at 3 days after cardiopulmonary resuscitation. Serum S100 B levels were remarkably decreased and neurological deficit scores were obviously improved in the mesenchymal stem cell group compared with the phosphate-buffered saline group. Brains were isolated from the rats and expression levels of 90 proteins were determined using a RayBio Rat Antibody Array, to investigate the cytokine profiles. Brain levels of the inflammatory mediators tumor necrosis factor-α, interferon-γ, macrophage inflammatory protein-1α, macrophage inflammatory protein-2, macrophage inflammatory protein-3α, macrophage-derived chemokine, and matrix metalloproteinase-2 were decreased ≥ 1.5-fold, while levels of the anti-inflammatory factor interleukin-10 were increased ≥ 1.5-fold in the mesenchymal stem cell group compared with the control group. Donor mesenchymal stem cells were detected by immunofluorescence to determine their distribution in the damaged brain, and were primarily observed in the cerebral cortex. These results indicate that bone marrow-derived mesenchymal stem cell transplantation attenuates brain damage induced by cardiac arrest and cardiopulmonary resuscitation, possibly via regulation of inflammatory mediators. This experimental protocol was approved by the Institutional Animal Care and Use Committee of Fujian Medical University, China in January 2016(approval No. 2016079).

Effect of metronome rates on the quality of bag-mask ventilation during metronome-guided 30:2 cardiopulmonary resuscitation:A randomized simulation study

BACKGROUND: Metronome guidance is a feasible and effective feedback technique to improve the quality of cardiopulmonary resuscitation(CPR). The rate of the metronome should be set between 100 to 120 ticks/minute and the speed of ventilation may have crucial effect on the quality of ventilation. We compared three different metronome rates(100, 110, 120 ticks/minute) to investigate its effect on the quality of ventilation during metronome-guided 30:2 CPR.METHODS: This is a prospective, randomized, crossover observational study using a Respi Trainer r. To simulate 30 chest compressions, one investigator counted from 1 to 30 in cadence with the metronome rate(1 count for every 1 tick), and the participant performed 2 consecutive ventilations immediately following the counting of 30. Thirty physicians performed 5 sets of 2 consecutive(total 10) bag-mask ventilations for each metronome rate. Participants were instructed to squeeze the bag over 2 ticks(1.0 to 1.2 seconds depending on the rate of metronome) and defl ate the bag over 2 ticks. The sequence of three different metronome rates was randomized.RESULTS: Mean tidal volume significantly decreased as the metronome rate was increased from 110 ticks/minute to 120 ticks/minute(343±84 m L vs. 294±90 m L, P=0.004). Peak airway pressure significantly increased as metronome rate increased from 100 ticks/minute to 110 ticks/minute(18.7 vs. 21.6 mm Hg, P=0.006).CONCLUSION: In metronome-guided 30:2 CPR, a higher metronome rate may adversely affect the quality of bag-mask ventilations. In cases of cardiac arrest where adequate ventilation support is necessary, 100 ticks/minute may be better than 110 or 120 ticks/minute to deliver adequate tidal volume during audio tone guided 30:2 CPR.

Effects of mild hypothermia on the ROS and expression of caspase-3 m RNA and LC3 of hippocampus nerve cells in rats after cardiopulmonary resuscitation

BACKGROUND: Cardiac arrest(CA) is a common and serious event in emergency medicine. Despite recent improvements in resuscitation techniques, the survival rate of patients with CA is unchanged. The present study was undertaken to observe the effect of mild hypothermia(MH) on the reactive oxygen species(ROS) and the effect of neurological function and related mechanisms.METHODS: Sixty-five healthy male Sprague Dawley(SD) adult rats were randomly(random number) divided into 2 groups: blank control group(n=5) and CPR group(n=60). CA was induced by asphyxia. The surviving rats were randomly(random number) divided into two groups: normothermia CPR group(NT) and hypothermia CPR group(HT). Normothermia of 37 °C was maintained in the NT group after return of spontaneous circulation(ROSC), hypothermal intervention of 32 °C was carried out in the HT group for 4 hours immediately after ROSC. Both the NT and HT groups were then randomly divided into 2 subgroups 12 hours and 24 hours after ROSC(NT-12, NT-24, HT-12, HT-24 subgroups). During observation, the neurological defi cit scores(NDSs) was recorded, then the bilateral hippocampi were obtained from rats' head, and monoplast suspension of fresh hippocampus tissue was made immediately to determine the level of intracellular ROS by flow cytometry. Transmission electron microscope was used to observe the ultramicro changes of cellular nucleus and mitochondria. Reverse transcription-polymerase chain reaction(RT-PCR) was used to determine the expression of caspase-3 m RNA, and western-blotting(WB) was used to determine the level of LC3 in frozen hippocampus tissue. Measured data were analyzed with paired sample t test and One-Way ANOVA.RESULTS: Of 60 rats with CA, 44(73%) were successfully resuscitated and 33(55%) survived until the end of the experiment. The NDSs of rats in the NT and HT groups were more signifi cantly reduced than those in the BC group(F=8.107, P<0.05), whereas the NDSs of rats in the HT-12 and HT-24 subgroups were significantly increased in comparison with those NDSs of rats in the NT-12 and NT-24 subgroups, respectively(t=9.692, P<0.001; t=14.374, P<0.001). The ROS in hippocampus nerve cells in the NT and HT groups signifi cantly increased compared to the BC group(F=16.824, P<0.05), whereas the ROS in the HT-12 and HT-24 subgroups significantly reduced compared with that ROS in the NT-12 and NT-24 subgroups, respectively(t=9.836, P<0.001; t=7.499, P<0.001). The expression of caspase-3 m RNA in hippocampus nerve cells in the NT and HT groups were signifi cantly increased compared to the BC group(F=24.527, P<0.05), whereas the expression of caspase-3 m RNA in rats of the HT-12 and HT-24 subgroups was signifi cantly reduced compared to the NT-12 and NT-24 subgroups, respectively(t=6.935, P<0.001; t=4.317, P<0.001). The expression of LC3B-II/I in hippocampus nerve cells of rats in the NT and HT groups signifi cantlyincreased compared to the BC group(F=6.584, P<0.05), whereas the expression of LC3B-II/I in rats of the HT-12 and HT-24 subgroups significantly reduced compared to the NT-12 and NT-24 subgroups, respectively(t=10.836, P<0.001; t=2.653, P=0.02). Ultrastructure damage of nucleus and mitochondria in the NT group was more evident than in the BC group, and eumorphism of nucleus and mitochondria were maintained in rats of the HT group compared with the NT group.CONCLUSION: Mild hypothermia lessened the injury of nerve cells and improved the neurological function of rats that survived from cardiac arrest by reducing the ROS production of nerve cells and inhibiting the expression of caspase-3 m RNA and LC3, leading to cellular apoptosis and massive autophagy in rats that survived from cardiac arrest after CPR.

Social attitude and willingness to attend cardiopulmonary resuscitation training and perform resuscitation in the Crimea

BACKGROUND: To promote potentially life-saving bystander cardiopulmonary resuscitation(CPR), the proportion of CPR-trained general public and their attitude toward CPR should be assessed, which is yet to be done in the former Soviet Union countries. As a case study, the survey is aimed to investigate the prevalence of CPR training, CPR knowledge, attitude and willingness to attend training and attempt CPR in the general population of the Crimea.METHODS: A personal interview survey was done from November 2017 to January 2018 with quota sampling refl ecting age, gender and territorial distribution of the Crimean population.RESULTS: Out of 384 persons surveyed, 53% were trained in CPR. Of trained, 24% passed training within the last year, 44% attended a single course. Among the non-trained, 51% never thought about the need to attend training. Knowledge of CPR is generally poor. About 52% wish to learn CPR, 79% and 91% are willing to attempt CPR on a stranger or a loved one, respectively. Lack of knowledge is the strongest barrier to attempt CPR. People aged ≥60, those with educational level lower than high school, widowed and retired are mostly untrained and unwilling to learn CPR. Females and unemployed are mostly untrained, but willing to be educated.CONCLUSION: There is a need for increasing CPR training and retraining, and improving awareness and motivation to learn CPR in the Crimean population, targeting the least trained groups. The results could be used as a reference point for future studies in the former USSR countries, utilising the same methodology.