Effect of Shen-Fu Injection Pretreatment to Myocardial Metabolism During Untreated Ventricular Fibrillation in a Porcine Model / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Shen-Fu injection (SFI) can attenuate ischemia-reperfusion injury, protect cardiac function, and improve microcirculation during cardiopulmonary resuscitation. We hypothesized that SFI may also have an influence on myocardial metabolism during ventricular fibrillation (VF). In this study, we used SFI pretreatment prior to VF to discuss the changes of myocardial metabolism and catecholamine (CA) levels during untreated VF, trying to provide new evidence to the protection of SFI to myocardium.</p><p><b>METHODS</b>Twenty-four pigs were divided into three groups: Saline group (SA group), SFI group, and SHAM operation group (SHAM group). Thirty minutes prior to the induction of VF, the SFI group received 0.24 mg/ml SFI through an intravenous injection; the SA group received an equal amount of sodium chloride solution. The interstitial fluid from the left ventricle (LV) wall was collected through the microdialysis tubes during VF. Adenosine diphosphate (ADP), adenosine triphosphate (ATP), and Na + -K + -ATPase and Ca2 + -ATPase enzyme activities were measured after untreated VF. Peak-to-trough VF amplitude and median frequency were analyzed for each of these 5-s intervals.</p><p><b>RESULTS</b>The levels of glucose and glutamate were lower after VF in both the SA and SFI groups, compared with baseline, and the levels in the SFI group were higher than those in the SA group. Compared with baseline, the levels of lactate and the lactate/pyruvate ratio increased after VF in both SA and SFI groups, and the levels in the SFI group were lower than those in the SA group. In both the SA and SFI groups, the levels of dopamine, norepinephrine, and epinephrine increased significantly. There were no statistical differences between the two groups. The content of ATP, ADP, and phosphocreatine in the SFI group was higher than those in the SA group. The activity of LV Na + -K + -ATPase was significantly higher in the SFI group than in the SA group. Amplitude mean spectrum area (AMSA) was significantly lower in the SA and SFI groups at 8- and 12-min compared with 4-min. The AMSA in the SFI group was higher than that in the SA group at each time point during untreated VF.</p><p><b>CONCLUSIONS</b>SFI pretreatment can improve myocardial metabolism and reduce energy exhaustion during VF, and it does not aggravate the excessive secretion of endogenous CAs.</p>

Effects of chest compressions on cardiorespiratory function in a non-arrested porcine model / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The effects of chest compressions to hemodynamic and respiratory parameters during hands-only cardiopulmonary resuscitation (CPR) in a non-arrested patient who suddenly collapses are confusing. In this research, we investigated the effects of chest compressions in a non-arrested porcine model.</p><p><b>METHODS</b>Fourteen male domestic pigs were randomized into sham control group (SHAM group, only anesthetized and instrumented without chest compression, n = 6) or chest compression group (CC group, 2 minutes of chest compressions, n = 8). Continuous hemodynamic parameters, dynamic lung compliance (Cdyn), and blood gas analysis outcomes were recorded. Serum levels of catecholamine were measured at baseline and 2 minutes, 30 minutes, 4 hours, and 24 hours after chest compressions. Chest computed tomography (CT) was performed at 30 minutes and 24 hours. Conventional histopathology evaluation was performed.</p><p><b>RESULTS</b>After two minutes of chest compressions in the CC group, heart rate and extravascular lung water increased significantly; mean arterial pressure, stroke volume, and global ejection fraction significantly decreased. Cdyn significantly decreased to valley levels at 30 minutes and slowly recovered. Compared with the baseline, serum levels of catecholamine significantly increased at 2 minutes and rapidly decreased 24 hours later. At 30 minutes after chest compressions, chest CT showed local exudation, which was absorbed 24 hours later.</p><p><b>CONCLUSIONS</b>This research showed that 2 minutes of chest compressions causes various heart and lung tissue damage in the normal a normal porcine model. It also impacts the hemodynamic and Cdyn.</p>

Relationship between intrathoracic pressure and hemodynamics during cardiopulmonary resuscitation in a porcine model of prolonged cardiac arrest / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The 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.</p><p><b>METHODS</b>After 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.</p><p><b>RESULTS</b>Average 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).</p><p><b>CONCLUSIONS</b>ITP 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.</p>

Evaluation of respiratory dysfunction in a pig model of severe acute dichlorvos poisoning / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Respiratory failure is the main cause of death in acute organophosphorus pesticide poisoning. In this study, a pulse-induced contour cardiac output monitor was used to evaluate the respiratory status in a pig model of acute dichlorvos poisoning.</p><p><b>METHODS</b>Twenty female pigs were randomly allocated to dichlorvos (n = 7), atropine (n = 7), and control (n = 6) groups. In the dichlorvos group, pigs were administered 80% emulsifiable dichlorvos (100 mg/kg) via a gastric tube. In the atropine group, pigs were similarly administered dichlorvos, and 0.5 hours later, atropine was injected to attain and maintain atropinization. The control group was administered saline solution. Arterial blood gas was measured at 0, 0.5, 1, 2, 4, and 6 hours post-injection. The extravascular lung water index and pulmonary vascular permeability index were recorded by the pulse-induced contour cardiac output monitor. At termination of the study, the animals were euthanized, the lung wet-to-dry weight ratio was determined, and histopathology was observed.</p><p><b>RESULTS</b>In the dichlorvos group, the extravascular lung water index and pulmonary vascular permeability index were substantially increased from 0.5 hours and were particularly high within 1 hour. In the atropine group, these indices increased initially, but decreased from the 1-hour mark. The control group exhibited no obvious changes. In both the dichlorvos and atropine groups, the extravascular lung water index was negatively correlated with partial pressure of oxygen/fraction of inspiration oxygen (PO2/FiO2) and positively correlated with the pulmonary vascular permeability index. Compared with the control group, the lung wet-to-dry weight ratio markedly increased and the histopathological findings obviously changed in the dichlorvos group, but only mildly increased and changed, respectively, in the atropine group.</p><p><b>CONCLUSION</b>The extravascular lung water index is an appropriate and valuable parameter for assessment of respiratory function in acute dichlorvos poisoning.</p>

Seroepidemiological survey of sheep hepatitis E virus infection in Aksu region of Xinjiang Autonomous / 病毒学报

Four hundreds and ninety sheep sera from seven breeds raised at eight counties and one city of Aksu region in Xinjiang were tested by ELISA for the presence of antibodies against hepatitis E virus (HEV), and the positive rate differences were compared based on administrative areas, breeds and age by Chi-square test. The result showed that the general positive rate was 28.98% (142/490), the positive rate were 35.44% (28/79), 29.67% (27/91), 20% (4/20), 40% (12/30), 32.5% (26/80), 38% (19/50), 22.5% (9/40), 8% (4/50) and 26% (13/50) respectively in eight counties and one city, there was a significant difference between Xayar and other administrative areas (P<0.01); there was also a significant difference among age ranges (P<0.01), being 38.75% (31/80) over 2 years old, 15.45% (17/110) below 1 year old; The seroprevalence was still related to breeds, i. e. there was a significant difference between Mongolia sheep and other breeds (P<0.01). From these data, it is confirmed that there is a possibility of previous and potential infection of sheep HEV in Aksu region of Xinjiang Autonomous.