OBJECTIVE: To compare the effects of different chest compression rates (60-140 times/min) on hemodynamic parameters, return of spontaneous circulation (ROSC), resuscitation success, and survival in a porcine model of cardiac arrest (CA) followed by cardiopulmonary resuscitation (CPR). METHODS: Forty healthy male domestic pigs were randomly divided into five groups based on chest compression rate: 60, 80, 100, 120, and 140 times/min (n = 8). All animals underwent standard anesthesia and tracheal intubation. A catheter was inserted via the left femoral artery into the thoracic aorta to monitor aortic pressure (AOP), and another via the right external jugular vein into the right atrium to monitor right atrial pressure (RAP). In each group, animals were implanted with a stimulating electrode via the right external jugular vein to the endocardium, and ventricular fibrillation (VF) was induced by delivering alternating current stimulation, resulting in CA. After a 1-minute, manual chest compressions were performed at the assigned rate with a compression depth of 5 cm. The first defibrillation was delivered after 2 minutes of CPR. No epinephrine or other pharmacologic agents were administered during the entire resuscitation process. From 1 minute before VF induction to 10 minutes after ROSC, dynamic monitoring of AOP, coronary perfusion pressure (CPP), and partial pressure of end-tidal carbon dioxide (P_ETCO₂). Cortical ultrastructure was examined 24 hours post-ROSC using transmission electron microscopy. RESULTS: With increasing compression rates, both the total number of defibrillations and cumulative defibrillation energy significantly decreased, reaching their lowest levels in the 120 times/min group. The number of defibrillations decreased from (4.88±0.83) times in the 60 times/min group to (2.25±0.71) times in the 120 compressions/min group, and energy from (975.00±166.90)J to (450.00±141.42)J. However, both parameters increased again in the 140 times/min group [(4.75±1.04)times, (950.00±207.02)J], the differences among the groups were statistically significant (both P < 0.01). As compression frequency increased, P_ETCO₂, pre-defibrillation AOP and CPP significantly improved, peaking in the 120 times/min group [compared with the 60 times/min group, P_ETCO₂ (mmHg, 1 mmHg≈0.133 kPa): 18.69±1.98 vs. 8.67±1.30, AOP (mmHg): 95.13±7.06 vs. 71.00±6.41, CPP (mmHg): 14.88±6.92 vs. 8.57±3.42]. However, in the 140 times/min group, these values declined significantly again [P_ETCO₂, AOP, and CPP were (10.59±1.40), (72.38±11.49), and (10.36±4.57) mmHg, respectively], the differences among the groups were statistically significant (all P < 0.01). The number of animals achieving ROSC, successful resuscitation, and 24-hour survival increased with higher compression rates, reaching a peak in the 120 times/min group (compared with the 60 times/min group, ROSC: 7 vs. 2, successful resuscitation: 7 vs. 2, 24-hour survival: 7 vs.1), then decreased again in the 140 times/min group (the animals that ROSC, successfully recovered and survived for 24 hours were 3, 3, and 2, respectively). Transmission electron microscopy revealed that in the 60, 80, and 140 times/min groups, nuclear membranes in cerebral tissue were irregular and incomplete, nucleoli were indistinct, and mitochondria were swollen with reduced cristae and abnormal morphology. In contrast, the 100 times/min and 120 times/min groups exhibited significantly attenuated ultrastructural damage. CONCLUSIONS Among the tested chest compression rates of 60-140 times/min, a chest compressions frequency of 120 times/min is the most favorable hemodynamic profile and outcomes during CPR in a porcine CA model. However, due to the wide spacing between groups, further investigation is needed to determine the optimal compression rate range more precisely.
Animals ; Cardiopulmonary Resuscitation/methods* ; Swine ; Male ; Heart Arrest/therapy* ; Heart Massage/methods* ; Hemodynamics

Objective:To observe the therapeutic effect of echinacoside (ECH) on liver injury and glucose metabolism disorder in sepsis rats induced by cecal ligation and puncture (CLP), and to explore its possible mechanism.Methods:Forty eight male Sprague Dawley (SD) rats were randomly divided into four groups: sham group (sham), model group (CLP), treatment group (CLP+ ECH) and inhibitor group (CLP+ ECH+ EX527). The sham group only received laparotomy, and the model group underwent CLP. The treatment group was intragastric administration of echinacea (30 mg/kg) every day after CLP modeling. The inhibitor group was injected with silence information regulator 1 (SIRT1) inhibitor EX527 (5 mg/kg) one hour before CLP, and then treated the same as the treatment group. Fasting blood glucose, insulin and serum biochemical indexes were detected in virous groups. The serum levels of interleukin (IL)-1 β, IL-6 and tumor necrosis factor-α(TNF-α) were detected by enzyme-linked immunosorbent assay (ELISA). 2′, 7′- dichlorofluorescein diacetate (DCFH-DA) staining was used to observe the production of reactive oxygen species (ROS) in liver tissue of rats in each group; hematoxylin-eosin (HE) staining was used to observe the pathological changes of liver tissue in each group; The expressions of SIRT1, glucose-6-phosphatase (G6Pase), phosphoenolpyruvate carboxykinase (PEPCK), phosphorylated signal transducers and activators of transcription 3 (p-STAT3) and phosphorylated protein ki-nase B(p-AKT) were detected by Western blot.Results:Compared with sham group, the levels of serum glucose, serum insulin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), ROS, IL-1β, IL-6 and TNF-α in model group increased, while the liver glycogen and survival rate decreased (all P<0.05). After echinacoside treatment, the serum glucose, serum insulin, ALT, AST, ROS , IL-1β, IL-6 and TNF-α levels decreased, and the liver glycogen and survival rate increased (all P<0.05); After SIRT1 inhibitor intervention, the levels of serum insulin, ALT, AST, IL-6 and ROS in the inhibitor group increased ( P<0.05). HE staining showed that there were infiltration and necrosis of inflammatory cells in the liver tissue of model group, and echinacoside could significantly reduce the focal and massive necrosis; Western blot showed that compared with the sham group, the expression levels of SIRT1, p-STAT3 and p-AKT protein in the model group decreased, while the expression levels of G6Pase and PEPCK protein increased ( P<0.05); After echinacoside treatment, the expression levels of SIRT1, p-STAT3 and p-AKT increased, while the expression levels of G6Pase and PEPCK decreased ( P<0.05). After SIRT1 inhibitor intervention, the expression of SIRT1, p-STAT3 and p-AKT protein decreased, and the expression of G6Pase and PEPCK protein increased in the inhibitor group ( P<0.05). Conclusions:Echinacoside is a potential therapeutic agent for sepsis associated liver injury and glucose metabolism disorders, which may play a role by targeting SIRT1 to activate STAT3 and AKT in the liver.