Cardiac arrest (CA) is a critical condition in the field of cardiovascular medicine. Despite successful resuscitation, patients continue to have a high mortality rate, largely due to post CA syndrome (PCAS). However, the injury and pathophysiological mechanisms underlying PCAS remain unclear. Experimental animal models are valuable tools for exploring the etiology, pathogenesis, and potential interventions for CA and PCAS. Current CA animal models include electrical induction of ventricular fibrillation (VF), myocardial infarction, high potassium, asphyxia, and hemorrhagic shock. Although these models do not fully replicate the complexity of clinical CA, the mechanistic insights they provide remain highly relevant, including post-CA brain injury (PCABI), post-CA myocardial dysfunction (PAMD), systemic ischaemia/reperfusion injury (IRI), and the persistent precipitating pathology. Summarizing the methods of establishing CA models, the challenges encountered in the modeling process, and the mechanisms of PCAS can provide a foundation for developing standardized CA modeling protocols.
Animals ; Disease Models, Animal ; Post-Cardiac Arrest Syndrome/physiopathology* ; Heart Arrest/physiopathology* ; Humans ; Ventricular Fibrillation/complications*

The ultimate goal of cardiac arrest-cardiopulmonary resuscitation (CA-CPR) is to reduce brain damage and promote neurological recovery. Although the return of spontaneous circulation (ROSC) has improved, the proportion of patients who survive to discharge is very low, so how to evaluate the recovery of brain function after resuscitation is particularly important in clinical work. From a clinical perspective, although early prognostic indicators are not perfect, identifying high-risk features may help clinicians determine the severity of brain injury caused by a patient's potential course of disease. This review, based on recent literature, selects several commonly used clinical brain function evaluation indicators to provide theoretical and practical support for assessing brain function recovery in patients after CPR.
Humans ; Cardiopulmonary Resuscitation/methods* ; Heart Arrest/physiopathology* ; Brain/physiopathology* ; Recovery of Function ; Prognosis

We described two patients who were successfully resuscitated from out-of-hospital cardiac arrest. Their ECGs showed ST elevations in V1 and aVR, as well as diffuse ST depression. Their ST elevation in V1 was noted to be greater than in aVR. While one patient was found to have an occlusion of the right ventricular (RV) branch of the right coronary artery, the other was found to have an occlusion of a proximal non-dominant right coronary artery supplying the RV branch. Successful primary percutaneous coronary intervention was performed for each patient with angioplasty and implantation of a drug-eluting stent. Both patients made good physical and neurological recovery.
Adult ; Angioplasty ; Angioplasty, Balloon, Coronary ; Cardiopulmonary Resuscitation ; Coronary Vessels ; physiopathology ; Defibrillators ; Drug-Eluting Stents ; Electrocardiography ; Heart Ventricles ; physiopathology ; Hepatitis B ; complications ; Humans ; Male ; Myocardial Infarction ; diagnosis ; physiopathology ; Out-of-Hospital Cardiac Arrest ; therapy ; Percutaneous Coronary Intervention ; Resuscitation ; Singapore

To investigate the changes of myocardial glucose metabolism in rabbit cardiac arrest models and the effect of hydrogen intervention by 18F-fluroro-2-deoxyglucose (18F-FDG) positron emission tomography (PET) imaging.
 Methods: Fifteen male New Zealand white rabbits were randomly divided into a hydrogen group (n=6), a control group (n=6) and a sham group (n=3). Cardiac arrest (CA) was induced by intravenous injection of potassium chloride. Conventional cardiopulmonary resuscitation (CPR) was initiated after five-minutes CA. The hydrogen group and the control group were mechanically ventilated into mixed gas with 4% hydrogen+96% oxygen and pure oxygen, respectively, for 30 minutes after CPR. Rats in the sham group was performed the same surgical procedure and was injected adrenaline and potassium chloride but did not induce CA. The vital signs at basic state and 30 min after return of spontaneous circulation (ROSC) were recorded in each group. The parameters of CPR were recorded in two CA groups. Myocardial glucose metabolism was assessed by positron emission tomography (PET) at basic state, 2 h and 24 h after ROSC. The maximum standardized uptake value (SUVmax) of 18F-FDG was measured.
 Results: There were no significant differences in the basal body weight and vital signs among the three groups. There was no significant difference in the blood glucose level before PET examination. The 18F-FDG SUVmax in the sham group at three time points was not significantly changed. In the hydrogen group and the control group, the 18F-FDG SUVmax at 2 h after ROSC were significantly higher than the basic level (1.89±0.47 vs 3.47±1.24 and 1.90±0.36 vs 4.26±0.80, respectively). Compared with the control group, the 18F-FDG SUVmax in the hydrogen group was lower at the point at 2 h after ROSC. The 18F-FDG SUVmax in the 2 CA group were down to the basic level at 24 h after ROSC (hydrogen group 2.02±0.64, control group 2.07±0.61).
 Conclusion: Myocardial glucose metabolism in CA rabbits was increased significantly after ROSC, and hydrogen intervention can reduce the degree of glucose metabolism.
Animals ; Cardiopulmonary Resuscitation ; Glucose ; metabolism ; Heart Arrest ; physiopathology ; surgery ; Male ; Myocardium ; metabolism ; Positron-Emission Tomography ; Rabbits ; Random Allocation ; Rats

BackgroundThe incidence of cancer, diabetes, and autoimmune diseases has been increasing. Furthermore, there are more and more patients with solid organ transplants. The survival rate of these immunocompromised individuals is extremely low when they are severely hit-on. In this study, we established cardiac arrest cardiopulmonary resuscitation (CPR) model in severe combined immunodeficient (SCID) mice, analyzed the expression and activation of mitochondrial autophagy and NLRP3 inflammasome/caspase-1, and explored mitochondrial repair and inflammatory injury in immunodeficiency individual during systemic ischemia-reperfusion injury.

MethodsA potassium chloride-induced cardiac arrest model was established in C57BL/6 and nonobese diabetic/SCID (NOD/SCID) mice. One hundred male C57BL/6 mice and 100 male NOD/SCID mice were randomly divided into five groups (control, 2 h post-CPR, 12 h post-CPR, 24 h post-CPR, and 48 h post-CPR). A temporal dynamic view of alveolar epithelial cells, macrophages, and neutrophils from bronchoalveolar lavage fluid (BALF) was obtained using Giemsa staining. Spatial characterization of phenotypic analysis of macrophages in the lung interstitial tissue was analyzed by flow cytometry. The morphological changes of mitochondria 48 h after CPR were studied by transmission electron microscopy and quantified according to the Flameng grading system. Western blotting analysis was used to detect the expression and activation of the markers of mitochondrial autophagy, NLRP3 inflammasome, and caspase-1.

Results(1) In NOD/SCID mice, macrophages were disintegrated in BALF, and many alveolar epithelial cells were shed at 48 h after resuscitation. Compared with C57BL/6 mice, the ratio of macrophages/total cells peaked at 12 h and was significantly higher in NOD/SCID mice (31.17 ± 4.13 vs. 49.69 ± 2.43, t = 14.46, P = 0.001). After 24 h, the results showed a downward trend. Furthermore, a large number of macrophages were disintegrated in the BALF. (2) Mitochondrial autophagy was present in both C57BL/6 and NOD/SCID mice after CPR, but it began late in the NOD/SCID mice. Compared with C57BL/6 mice, phos-ULK1 (Ser) expression was significantly lower at 2 h and 12 h after CPR (2 h after CPR: 1.88 ± 0.36 vs. 1.12 ± 0.11, t = -1.36, P < 0.01 and 12 h after CPR: 1.52 ± 0.16 vs. 1.05 ± 0.12, t = -0.33, P < 0.01), whereas phos-ULK1 (Ser) expression was significantly higher at 2 h and 12 h after CPR in NOD/SCID mice (2 h after CPR: 1.28 ± 0.12 vs. 1.69 ± 0.14, t = 1.7, P < 0.01 and 12 h after CPR: 1.33 ± 0.10 vs. 1.94 ± 0.13, t = 2.75, P < 0.01). (3) Furthermore, NLRP3 inflammasome/caspase-1 activation in the pulmonary tissues occurred early and for only a short time in C57BL/6 mice, but this phenomenon was sustained in NOD/SCID mice. The expression of the NLRP3 inflammasome increased modestly in the C57 mice, but the increase was higher in the NOD/SCID mice than in the C57BL/6 mice, especially at 12, 24, 48 h after CPR (48 h after CPR: 1.46 ± 0.13 vs. 2.97 ± 0.19, t = 5.34, P = 0.001). The expression of caspase-1-20 generally followed the same pattern as the NLRP3 inflammasome.

ConclusionsThere is a regulatory relationship between the NLRP3 inflammasome and mitochondrial autophagy after CPR in the healthy mice. This regulatory relationship was disturbed in the NOD/SCID mice because the signals for mitochondrial autophagy occurred late, and NLRP3 inflammasome- and caspase-1-dependent cell injury was sustained.

Animals ; Autophagy ; physiology ; Heart Arrest ; metabolism ; physiopathology ; Inflammasomes ; metabolism ; Lung ; metabolism ; physiopathology ; Macrophages ; metabolism ; physiology ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Inbred NOD ; Mice, SCID ; Mitochondria ; metabolism ; NLR Family, Pyrin Domain-Containing 3 Protein ; metabolism

OBJECTIVETo investigate the effects of Shenfu Injection (, SFI) on cerebral metabolism in a porcine model of cardiac arrest (CA).

METHODSThirty Wuzhishan minipigs were randomly assigned to the control group (n=6), epinephrine group (EP group, n=12) and Sfigroup (n=12). After 8 min of untreated ventricular fifibrillation (VF), pigs in the EP group or Sfigroup were administered with either EP (0.02 mg/kg) or Sfi(1.0 mL/kg), respectively. After successful resuscitation, cerebrospinal fluid (CSF) levels of glucose, pyruvate, lactate, glutamate and glycerol were measured at 1, 6, 12 and 24 h after recover from spontaneous circulation (ROSC). In addition, neurologic defificit score (NDS) was calculated at 24 h after ROSC. Surviving pigs were killed at 24 h after ROSC, and the brain tissue was obtained for ultra-microstructure examination.

RESULTSCompared with the EP group, CSF glucose and pyruvate levels were higher (all P<0.01), and lactate levels were lower in the Sfigroup (P<0.01). Meanwhile, CSF glutamate and glycerol levels in the Sfigroup were lower in comparison to the EP group (all P<0.05). In addition, Sfidecreased NDS at 24 h after ROSC (P<0.01), and alleviated the histopathological damage of the brain.

CONCLUSIONSSficould alleviate brain injury after CA, which may be associated with improving cerebral metabolism.

Animals ; Blood Circulation ; Blood Gas Analysis ; Brain ; drug effects ; metabolism ; ultrastructure ; Cardiopulmonary Resuscitation ; Disease Models, Animal ; Drugs, Chinese Herbal ; administration & dosage ; pharmacology ; therapeutic use ; Heart Arrest ; cerebrospinal fluid ; drug therapy ; physiopathology ; Injections ; Jugular Veins ; drug effects ; metabolism ; Perfusion ; Sus scrofa

OBJECTIVETo investigate whether Shen-Fu Injection (, SFI) reduces post-resuscitation immune dysfunction in a porcine model of cardiac arrest by modulating apoptosis of regulatory T lymphocytes (Treg) in the spleen.

METHODSAfter 8-min untreated ventricular fibrillation and 2-min basic life support, 24 pigs were divided into 3 groups with a random number table, i.e. SFI group, epinephrine (EP) group, and saline (SA) group (8 in each group), which received central venous injection of SFI (1.0 mL/kg), EP (0.02 mg/kg) and SA, respectively. The same procedure without CA initiation was achieved in the sham-operated (sham) group (n=6). After successful return of spontaneous circulation (ROSC), apoptosis rate of splenic Treg was detected by flow cytometry; and the mRNA expression of forkhead/winged helix transcription factor (Foxp3) of splenic Treg was detected by real time-polymerase chain reaction; and the levels of interleukin-4 (IL-4) and interferon-γ (IFN-γ) in porcine splenic Treg were detected by using enzyme-linked immunosorbent assay (ELISA).

RESULTSCompared with the sham group, the apoptosis rate of Treg was significantly decreased, and the levels of Foxp3 mRNA expression, IFN-γ, IL-4 and IFN-γ/IL-4 were increased in the SA group (P<0.05 or P<0.01). Compared with the EP and SA groups, SFI treatment increased the apoptosis rate of Treg and reduced the levels of Foxp3 mRNA expression, IFN-γ and IFN-γ/IL-4 (P<0.05).

CONCLUSIONSSFI has signifificant effects in attenuating post-resuscitation immune dysfunction by modulating apoptosis of Treg in the spleen.

Animals ; Apoptosis ; drug effects ; Cardiopulmonary Resuscitation ; Disease Models, Animal ; Drugs, Chinese Herbal ; administration & dosage ; pharmacology ; therapeutic use ; Forkhead Transcription Factors ; genetics ; metabolism ; Heart Arrest ; drug therapy ; immunology ; pathology ; physiopathology ; Hemodynamics ; drug effects ; Injections ; Interferon-gamma ; metabolism ; Interleukin-4 ; metabolism ; Lymphocyte Subsets ; drug effects ; metabolism ; Male ; Oxygen ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Spleen ; immunology ; Survival Analysis ; Swine ; Swine, Miniature ; T-Lymphocytes, Regulatory ; drug effects ; immunology

OBJECTIVETo compare the effects of Shenfu Injection (SFI) and epinephrine (EPI) on catecholamine levels in a porcine model of prolonged cardiac arrest (CA).

METHODSAfter 8 min of untreated ventricular fibrillation, 24 Wuzhishan miniature pigs were randomly assigned to one of the three groups (n=8 per group) and received central venous injection, respectively: SFI group (1 mL/kg), EPI group (20 μg/kg EPI), and normal saline (NS) group. Cardiac output (CO), maximum rate of increase/decrease in left ventricular pressure (±dp/dt), serum levels of EPI, norepinephrine (NE), and dopamine (DA) were determined at baseline and at 0.5, 1, 2, and 4 h after restoration of spontaneous circulation.

RESULTSThe duration of cardiopulmonary resuscitation was shorter in the EPI and SFI groups than in the NS group (P<0.05). The EPI level increased significantly after restoration of spontaneous circulation (ROSC) in all three groups, and was significantly different between the EPI group and the other two groups immediately after ROSC (both P<0.01), but these differences gradually disappeared over time. There were no significant differences in NE or DA levels among the three groups, and there were no correlations between catecholamine levels and CO or dp/dt (P>0.05).

CONCLUSIONSSFI did not significantly affect endogenous catecholamine levels during cardiopulmonary resuscitation after prolonged ventricular fibrillation. However, SFI improved oxygen metabolism, and produced a better hemodynamic status compared with EPI. SFI might be a potentially vasopressor drug for the treatment of CA.

Animals ; Cardiac Output ; drug effects ; Cardiopulmonary Resuscitation ; Catecholamines ; blood ; Disease Models, Animal ; Drugs, Chinese Herbal ; administration & dosage ; pharmacology ; therapeutic use ; Epinephrine ; pharmacology ; therapeutic use ; Heart Arrest ; blood ; drug therapy ; Heart Ventricles ; physiopathology ; Injections ; Lactic Acid ; blood ; Sus scrofa

BACKGROUNDMorbidity and mortality after resuscitation largely depend on the recovery of brain function. Ventricular fibrillation cardiac arrest (VFCA) and asphyxial cardiac arrest (ACA) are the two most prevalent causes of sudden cardiac death. Up to now, most studies have focused on VFCA. However, results from the two models have been largely variable. So, it is necessary to characterize the features of postresuscitation cerebral metabolism of both models.

METHODSForty-four Wuzhishan miniature inbred pigs were randomly divided into three groups: 18 for VFCA group, ACA group, respectively, and other 8 for sham-operated group (SHAM). VFCA was induced by programmed electric stimulation, and ACA was induced by endotracheal tube clamping. After 8 min without treatment, standard cardiopulmonary resuscitation (CPR) was initiated. Following neurological deficit scores (NDS) were evaluated at 24 h after achievement of spontaneous circulation, cerebral metabolism showed as the maximum standardized uptake value (SUVmax) was measured by 18 F-fluorodeoxyglucose positron emission tomography/computed tomography. Levels of serum markers of brain injury, neuron specific enolase (NSE), and S100β were quantified with an enzyme-linked immunosorbent assay.

RESULTSCompared with VFCA group, fewer ACA animals achieved restoration of spontaneous circulation (61.1% vs. 94.4%, P < 0.01) and survived 24-h after resuscitation (38.9% vs. 77.8%, P < 0.01) with worse neurological outcome (NDS: 244.3 ± 15.3 vs. 168.8 ± 9.71, P < 0.01). The CPR duration of ACA group was longer than that of VFCA group (8.1 ± 1.2 min vs. 4.5 ± 1.1 min, P < 0.01). Cerebral energy metabolism showed as SUVmax in ACA was lower than in VFCA (P < 0.05 or P < 0.01). Higher serum biomarkers of brain damage (NSE, S100β) were found in ACA than VFCA after resuscitation (P < 0.01).

CONCLUSIONSCompared with VFCA, ACA causes more severe cerebral metabolism injuries with less successful resuscitation and worse neurological outcome.

Animals ; Asphyxia ; complications ; physiopathology ; Brain ; metabolism ; Cardiopulmonary Resuscitation ; Heart Arrest ; metabolism ; pathology ; therapy ; Positron-Emission Tomography ; Swine ; Ventricular Fibrillation ; metabolism ; pathology ; therapy

BACKGROUNDAnimal models of asphyxiation cardiac arrest (ACA) are frequently used in basic research to mirror the clinical course of cardiac arrest (CA). The rates of the return of spontaneous circulation (ROSC) in ACA animal models are lower than those from studies that have utilized ventricular fibrillation (VF) animal models. The purpose of this study was to characterize the factors associated with the ROSC in the ACA porcine model.

METHODSForty-eight healthy miniature pigs underwent endotracheal tube clamping to induce CA. Once induced, CA was maintained untreated for a period of 8 min. Two minutes following the initiation of cardiopulmonary resuscitation (CPR), defibrillation was attempted until ROSC was achieved or the animal died. To assess the factors associated with ROSC in this CA model, logistic regression analyses were performed to analyze gender, the time of preparation, the amplitude spectrum area (AMSA) from the beginning of CPR and the pH at the beginning of CPR. A receiver-operating characteristic (ROC) curve was used to evaluate the predictive value of AMSA for ROSC.

RESULTSROSC was only 52.1% successful in this ACA porcine model. The multivariate logistic regression analyses revealed that ROSC significantly depended on the time of preparation, AMSA at the beginning of CPR and pH at the beginning of CPR. The area under the ROC curve in for AMSA at the beginning of CPR was 0.878 successful in predicting ROSC (95% confidence intervals: 0.773∼0.983), and the optimum cut-off value was 15.62 (specificity 95.7% and sensitivity 80.0%).

CONCLUSIONSThe time of preparation, AMSA and the pH at the beginning of CPR were associated with ROSC in this ACA porcine model. AMSA also predicted the likelihood of ROSC in this ACA animal model.

Animals ; Cardiopulmonary Resuscitation ; Heart Arrest ; physiopathology ; Logistic Models ; Swine