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

Due to its great clinical significance, brain injury following cardiac arrest (CA) has attracted more attention now. Meanwhile, there are currently no approved real time objective methods used to monitor brain injury following CA. In this study, we adopt the method of nonextensive Kullback-Leibler Entropy in investigating the HRV signals from brain injury and compare the result with that of corresponding EEG analysis. The comparative analysis shows that Kullback-Leibler Entropy can reveal the injury level of brain following CA. And we propose a novel quantitative approach for monitoring brain injury.
Algorithms ; Brain ; pathology ; physiopathology ; Brain Ischemia ; physiopathology ; Electroencephalography ; Heart Arrest ; complications ; Heart Rate ; physiology ; Humans

BACKGROUNDThe influences of intrathoracic pressure (ITP) to hemodynamic and respiratory parameters during cardiopulmonary resuscitation (CPR) are confusing. In this research, we investigated the phasic changes of ITP during CPR and reveal the relationships among the hemodynamics, respiratory parameters, and ITP.

METHODSAfter 8 minutes of untreated ventricular fibrillation, which was induced in twenty intubated male domestic pigs, 12 minutes of 30: 2 CPR was performed. Continuous respiratory variables, hemodynamics, ITP and blood gas analysis were measured during CPR. After that, defibrillation was done and prognostic indicators after CPR was recorded.

RESULTSAverage ITP at baseline was -(14.1 ± 1.6) mmHg (1 mmHg = 0.133 kPa). When gasping inspirations were going on, it decreased sharply to near -50 mmHg. ITP fluctuated up and down quickly from near -20 mmHg to 20 mmHg when compressions were performed. These phasic changes became mild as the CPR was performed, the contrast of high and low ITP decreased to (12.95 ± 2.91) mmHg at the end of 12 minutes of CPR. Total alveolus minute volume decreased too, because of the decrease of compression and gasp related ventilations. Curve correlation was found between the tidal volume of compression and ITP: ITP = 607.33/(1 + 3134 × e(-0.58 × TV)), (e: natural constant, R(2) = 0.895). Negative correlations were found between the right atrial diastolic pressure and ITP (r = -0.753, P < 0.01); and positive correlations were found between the coronary perfusion pressure and ITP (r = 0.626, P < 0.01).

CONCLUSIONSITP is one of the key factors which can influence the prognosis of CPR. Correlations were found between the changes of ITP and the tidal volumes of compressions, right atrial diastolic pressure and coronary perfusion pressure during CPR. More positive ITP during compression and more negative during decompression were good to ventilation and perfusion.

Animals ; Blood Gas Analysis ; Cardiopulmonary Resuscitation ; Heart Arrest ; physiopathology ; therapy ; Hemodynamics ; Male ; Pressure ; Respiration ; Sus scrofa

Cardiopulmonary Resuscitation ; adverse effects ; Chylothorax ; etiology ; Heart Arrest ; physiopathology ; Humans ; Infant ; Infant, Newborn ; Male ; Neonatology

Adult ; Aged ; Female ; Heart Arrest ; physiopathology ; therapy ; Humans ; Intensive Care Units ; Male ; Middle Aged ; Multivariate Analysis ; Retrospective Studies ; Risk Factors

OBJECTIVETransesophageal echocardiography was performed during closed-chest cardiopulmonary resuscitation (CPR) in in-hospital cardiac arrest to further explore the hemodynamic mechanism of CPR.

METHODSCPR attempts were performed according to advanced cardiovascular life support guidelines in 6 cases of in-hospital cardiac arrest. Multi-plane transesophageal echocardiography was carried out within 15 min of initiation of CPR. Throughout CPR, the motion of the mitral, tricuspid and aortic valves, the changes in the left ventricular cavity size and the thoracic aortic diameter were observed. Trans-mitral and trans-aortic Doppler files of blood flow were also documented.

RESULTSA closure of the mitral and tricuspid valves with simultaneous opening of the aortic valve occurred exclusively during chest compression, resulting in forward blood flow in the pulmonary and systemic circulation. Peak forward aortic flow at a velocity of 58.8 +/- 11.6 cm/s was recorded during the compression phase. Whereas, a closure of the aortic valve and rapid opening of the atrioventricular valves associated with ventricular filling during relaxation of chest compression was noted in all 6 patients. Peak forward mitral flow at a velocity of 60.6 +/- 20.0 cm/s was recorded during the release phase. Mitral regurgitation during the chest compression period was detected in 5 patients, reflecting a positive ventricular-to-atrial pressure gradient. A reduction in the left ventricular chamber and an increase in the thoracic aortic diameter during the compression phase was found in all patients, indicating that direct cardiac compression contributed to forward blood flow.

CONCLUSIONThese observations favor the cardiac pump theory as the predominant hemodynamic mechanism of forward blood flow during CPR in human beings.

Aged ; Aged, 80 and over ; Cardiopulmonary Resuscitation ; Echocardiography, Transesophageal ; Female ; Heart Arrest ; diagnostic imaging ; physiopathology ; therapy ; Hemodynamics ; Humans ; Male ; Middle Aged

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

OBJECTIVE: To investigate the methods to alleviate lung injury of non-heart-beating donor to attain better structure and function. METHODS: Sixty-four Sprague-Dawley rats were randomly divided into 4 groupsú a heart-beating donor group(HBD group), a non-heart-beating donor group without protective measures(NHBD-N group), a non-heart-beating donor group with continuous mechanical ventilation or with topical cooling on cadaver lung (NHBD-V group and NHBD-I group). After the transplantation, lung compliance,pulmonary function,wet/dry ratio of lung and content of energy metabolism were compared among the 4 groups. RESULTS: Due to the longer warm ischemic period, NHBD lungs suffered more injuries than HBD lungs. However, compared with NHBD-N group, the wet/dry ratio of the lung in NHBD-V group and NHBD-I group was lower(5.28+/-1.24,4.21+/-0.85,4.14+/-1.33,P<0.01),the lung injury index (14.35+/-3.21,11.28+/-3.26,10.41+/-2.85, P<0.01)and the count of white blood cells(425.60+/-86.47,316.30+/-56.24,295.50+/-70.26, P<0.01) were milder, while the lung compliance and preservation of energetic metabolte were better in the NHBD-V group and the NHBD-I group. CONCLUSION Continuous mechanical ventilation or topical cooling may protect the NHBD lung during the warm ischemic period.
Animals ; Cadaver ; Heart Arrest ; metabolism ; physiopathology ; Lung ; metabolism ; physiopathology ; Lung Compliance ; Lung Transplantation ; methods ; Male ; Organ Preservation ; methods ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Time Factors ; Tissue Donors

OBJECTIVETo explore the appropriate temperature of the kalium-verapamil-propranolol (KVP) cardioplegia by observation of the effect on the function of the immature rat heart.

METHODSIsolated hearts from immature rats were perfused by Langendorff method, and assigned to 1 of the following 5 groups (n = 6-8): control, continuously perfused for 170 min at 36 degrees C, normal temperature, normal perfused for 20 min, changed to perfuse with KVP for 3 min then no perfusion 87 min (ischemia 90 min), followed by 60 min reperfusion. 3 groups of low temperature, perfused for 15 min, cool down to 32 degrees C, 28 degrees C and 24 degrees C especially in 5 min, and at 20th min. heart rate (b/min), tension (g), contraction force (g), peak systolic velocity (dT/dt(max)), peak diastole velocity (dT/dt(max)), coronary flow (Drop/min) were monitored during the whole perfusion.

RESULTSCompared to control group, the heart tension increased after 50 min KVP ischemia. The protection of KVP in normal temperature (36 degrees C) was better than lower temperature (32 degrees C, 28 degrees C, 24 degrees C) such as reducing bad contraction, keeping normal myocardium tension,recovering heart rate, recovering the fuction of contraction force and protecting the coronary flow.

CONCLUSIONThe KVP cardioplegia in normal temperature has the better effect than that in hypothermia to protect the immature heart.

Animals ; Cardioplegic Solutions ; pharmacology ; Heart ; physiopathology ; Heart Arrest, Induced ; In Vitro Techniques ; Male ; Myocardial Reperfusion Injury ; prevention & control ; Rats ; Rats, Sprague-Dawley ; Temperature ; Ventricular Dysfunction ; prevention & control

This study investigated the feasibility and effects of organ bath to be used for detection of bronchial function of non-heart-beating donor (NHBD) lung after 1-h warm ischemia. Sixteen Swedish pigs were divided into two groups randomly: heart-beating donor (HBD) group and NHBD with 1-h warm ischemia (NHBD-1 h) group. The bronchial rings whose lengths and inner diameters were both 1.5 mm were obtained from isolated left lungs of all the pigs. Acetylcholine, arachidonic acid natrium and papaverine were used to test and compare the contractile and relaxant function of bronchial smooth muscles and epithelium-dependent relaxation (EpiDR) response between HBD and NHBD-1 h groups. The results showed that there was no significant difference in the values of bronchial precontraction between HBD and NHBD-1 h groups (5.18+/-0.07 vs 5.10+/-0.11 mN, P>0.05). No significant difference in the values of EpiDR responses between HBD and NHBD-1 h groups (1.26+/-0.05 vs 1.23+/-0.07 mN, P>0.05) was observed either. During the process of EpiDR induction, the rings had no spontaneous relaxation in two groups. In addition, papaverine solution completely relaxed the bronchial smooth muscles of all bronchial rings. It was concluded that after warm ischemia for 1 h, the contractile and relaxant abilities of bronchial smooth muscles, and the epithelium-dependent adjustment both kept intact. Organ bath model could be a liable and scientific way to evaluate the bronchial function of NHBD lung.
Biological Factors/metabolism ; Bronchi/metabolism ; Bronchi/*physiology ; Heart Arrest/*metabolism ; Heart Arrest/physiopathology ; Lung Transplantation ; Models, Biological ; Muscle Relaxation/physiology ; Organ Preservation/*methods ; Random Allocation ; Reperfusion Injury/prevention & control ; Swine ; Tissue and Organ Procurement ; Warm Ischemia/*methods