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Bu çalışma Uludağ Üniversitesi Tıp Fakültesi Kardiyoloji Anabilim Dalında göğüs ağrısı nedeni ile takip edilen ve koroner anjiyografi yapılan hastalarda, koroner arter hastalığı derecesinin, aort distensibilitesi, koroner perfüzyon basıncı ve miyokardiyal blush skoru üzerine etkisini araştırmak amacıyla yapılmıştır. Retrospektif olarak 2019 yılından sonra koroner anjiyografi yapılmış olan hastalarda invazif olarak aort distensibilitesi, miyokard blush skoru ve koroner perfüzyon basınçları ölçülmüştür. Bu ölçümlerin yapılabilmesi için ventrikül ve aort basınç kayıtları mevcut olan hastalar çalışmaya dahil edilmiştir. Hastaların miyokard perfüzyonunu değerlendirmek için miyokardiyal blush skoru ölçülmüştür. Bunun için yeterli süre ile cineanjiyografi yapılmış hastalar seçilmiştir. Koroner baypas yapılmış olan hastalar çalışma dışı bırakılmıştır. Çalışmaya toplam 56 hasta alınmıştır. Gensini skorlaması koroner arter hastalığının şideti ve yaygınlığını değerlendirmek için kullanılmıştır. Koroner anjiyografisi tamamen normal olan hasta sayısı 28 olup hastaların yarısını oluşturmuştur. Hafif koroner hastalık 11 hastada, ciddi koroner arter hastalığı 17 hastada tespit edilmiştir. Bunlar çalışma gruplarını oluşturmuş ve istatiksel karşılaştırmalar bu gruplar üzerinden yapılmıştır. İstatistiksel değerlendirmede frekans dağılımı, ortalama ± standart sapma verilmiş gruplar arası karşılaştırmalarda Kruskal Wallis testi kullanılmıştır. Çalışmaya dahil edilen hastaların yaş ortalaması 61.05±9.07 bulunmuştur. Koroner arter hastalığı şiddeti ve yaygınlığı ile ortalama arter basıncı, aort sistolik basıncı, aort diyastolik basıncı ve total miyokardiyal blush skoru arasında istatistiksel olarak anlamlı ilişkili bulunmuştur. The study was conducted to investigate the effect of the degree of coronary artery disease on aortic distensibility, coronary perfusion pressure and myocardial blush score in patients who were followed up with chest pain and coronary angiography in Uludağ University Faculty of Medicine Department of Cardiology. Retrospectively, aortic distensibility and myocardial blush score and coronary perfusion pressures were measured invasively in patients who underwent coronary angiography after 2019. In order to make these measurements, patients with ventricular and aortic pressure records were included in the study. Myocardial blush score was measured to evaluate myocardial perfusion of patients. For this, patients who have undergone cineangiography for a sufficient period of time were selected. Patients who underwent coronary bypass were excluded from the study. A total of 56 patients were included in the study. Gensini scoring has been used to assess the severity and prevalence of coronary artery disease. The number of patients with completely normal coronary angiography was 28 and constituted half of the patients. Mild coronary disease was detected in 11 patients and severe coronary artery disease in 17 patients. These constituted the study groups and statistical comparisons were made through these groups. Kruskal-Wallis test was used in nonparametric comparison of groups. Again, frequencies and average ± standard deviation were used. The mean age of the patients included in the study was 61.05 ± 9.07. The severity and prevalence of coronary artery disease were associated with mean arterial pressure, aortic systolic and diastolic pressure, and total myocardial blush score.

Objective Experimental studies of head-up positioning (HUP) during cardiopulmonary resuscitation (CPR) have had some degree of conflicting published results. The current study aim was to analyze and reconcile those discrepancies in order to better clarify the effects of HUP CPR compared to conventional supine (SUP) CPR. Methods Three databases (PubMed, EMBASE and Cochrane Library) were searched comprehensively (from each respective database's inception to May 2021) for articles addressing HUP CPR. The primary outcome to be observed was cerebral perfusion pressure (CerPP), and secondary outcomes were mean intracranial pressure (ICP), mean arterial pressure (MAP), coronary perfusion pressure (CoPP) and frequencies of return of spontaneous circulation (ROSC). Results Seven key studies involving 131 animals were included for analysis. Compared to SUP CPR, CerPP (MD 10.37; 95% CI 7.11–13.64; p I2 = 58%) and CoPP (MD 7.56; 95% CI 1.84–13.27, p = 0.01; I2 = 75%) increased significantly with HUP CPR, while ICP (MD − 13.66; 95% CI − 18.6 to –8.71; p I2 = 96%) decreased significantly. Combining all study methodologies, there were no significant differences detected in MAP (MD − 1.63; 95% CI − 10.77–7.52; p = 0.73; I2 = 93%) or frequency of ROSC (RR 0.9; 95% CI 0.31–2.60; p = 0.84; I2 = 65%). However, in contrast to worse outcomes in studies using immediate elevation of the head in a reverse Trendelenburg position, study outcomes were significantly improved when HUP (head and chest only) was introduced in a steady, graduated manner following a brief period of basic CPR augmented by active compression–decompression (ACD) and impedance threshold (ITD) devices. Conclusion In experimental models, gradually elevating the head and chest following a brief interval of circulatory priming with ACD and ITD devices can enhance CoPP, lower ICP and improve CerPP significantly while maintaining MAP. This effect is immediate, remains sustained and is associated with improved outcomes.

Aims Right ventricle adaptation to prolonged exposure against pulmonary hypertension (PH) includes structural and functional abnormalities, translated into modifications of blood flow pattern through the right coronary artery. Given these changes, we investigate the relationship between right coronary artery diastolic perfusion pressure (RCDPP) and clinical outcome, in patients with PH secondary to left‐sided heart failure (HF). Methods and results We studied 108 HF patients who underwent right heart catheterization. PH was present in 75 (69.4%). Mean RCDPP was lower in patients with PH (59.4 ± 14.0 mmHg) as compared with no PH patients (65.5 ± 11.6 mmHg) (P = 0.03). Aortic diastolic pressure accounted for 79% of RCDPP variability explained by the model (P

Background/Aim. Dysfunctions at the cellular, tissue, and organ level, which can result in death, are caused by metabolic changes and affection on the regulation of gene transcription and micro- and macrocirculation. The aim of the present study was to assess the impact of hyperbaric oxygenation (HBO) on isolated heart as well as on the oxidative status of rats with sepsis. Methods. The investigation included male Wistar albino rats classified into three groups: the first group was a control group (CTRL); the second group included animals exposed only to the induction of sepsis without HBO treatment (the Sepsis group), while the third group included animals treated with HBO after the induction of sepsis (the Sepsis + HBO group). For the induction of sepsis, fecal peritonitis model was used (3 mL/kg of fecal suspension administered intraperitoneally). After the induction of sepsis, the rats were exposed twice a day (on 12 hours) to HBO treatment at 2.8 atmospheres absolute (ATA) for 90 minutes over a period of 3 days. 72 h after the confirmation of sepsis, the animals were sacrificed and the hearts were retrogradely perfused on the Langendorff apparatus at a gradually increased coronary perfusion pressure (CPP = 40?120 cm H2O). The following parameters of heart function were continuously recorded: maximum and minimum rate of left ventricular pressure development (dp/dt max, dp/dt min); systolic and diastolic left ventricular pressure (SLVP and DLVP); heart rate (HR). Coronary flow (CF) was measured flowmetrically. Following oxidative stress markers were measured: nitrites (NO2?), superoxide anion radical (O2?), hydrogen peroxide (H2O2), index of lipid peroxidation (TBARS), activity of superoxide dismutase (SOD) and catalase (CAT) and the level of reduced glutathione (GSH). Results. There were no significant differences in dp/dt max, dp/dt min, SLVP and HR between the groups. CF was statistically significantly higher (p < 0.01) in the sepsis group. The values of all cardiac oxidative markers were lower in the sepsis + HBO group (p < 0.05), while systemic pro-oxidative and antioxidative parameters were unchanged. Conclusion. Our results showed that HBO treatment was not associated with improved cardiac function and coronary perfusion, while expressed promising beneficial effects on cardiac oxidative stress.

Physiological or supraphysiological levels of testosterone appear to be associated with the development of risk factors for cardiovascular diseases such as hypertension, as this hormone modulates the release of endothelial factors. However, its actions are still controversial, especially in the coronary circulation of hypertensive animals. This study was designed to assess the effects of testosterone treatment (T) on endothelium-dependent coronary vascular reactivity in orchiectomized SHR. The animals were divided into SHAM, orchiectomized (ORX), ORX+T and ORX+T+aromatase inhibitor (AI). All treatments lasted 15 days. Blood pressure (BP) was measured. Dose–response curves to bradykinin (BK) were constructed using the Langendorff technique, followed by inhibition of endothelium mediators (NO, prostanoids, EETs) and potassium channels. The intensity of eNOS, COX-1, COX-2, Akt, and gp91phox protein expression was quantified by Western blotting. BP was elevated in SHAM, ORX+T, and ORX+T+AI groups. However, we did not observe differences in the ORX group. Baseline coronary perfusion pressure (CPP) remained unaffected. Orchiectomy did not change the BK-induced relaxation compared to the SHAM group, whereas testosterone treatment increased it. This response was diminished in the absence of NO, prostanoids, and EETs in the SHAM and ORX groups, while in ORX+T group the relaxation was diminished only in the absence of NO and EETs. There was no difference in eNOS, COX-1, COX-2, and gp91phox protein expression, though Akt expression was increased in ORX and ORX+T groups. These results show that testosterone treatment can modulate endothelial function, especially in the coronary circulation under hypertension conditions, via NO and EETs pathways.

Visual Abstract, Highlights • SNPeCPR improves coronary perfusion pressure, tissue perfusion, and carotid blood flow compared to epinephrine-based standard advanced cardiac life support. • In a porcine model of prolonged resuscitation, SNPeCPR was associated with decreased arterial oxygen saturation but improved tissue oxygen delivery due to improvement in blood flow. • Oxygen supplementation led to alleviation of hypoxemia and maintenance of the SNPeCPR hemodynamic benefits. • Arterial oxygen saturation must be a safety endpoint that will be prospectively assessed in the first SNPeCPR clinical trial in humans., Summary Sodium nitroprusside–enhanced cardiopulmonary resuscitation has shown superior resuscitation rates and neurologic outcomes in large animal models supporting the need for a randomized human clinical trial. This study is the first to show nonselective pulmonary vasodilation as a potential mechanism for the hemodynamic benefits. The pulmonary shunting that is created requires increased oxygen treatment, but the overall improvement in blood flow increases minute oxygen delivery to tissues. In this context, hypoxemia is an important safety endpoint and a 100% oxygen ventilation strategy may be necessary for the first human clinical trial.

The search for safe and effective patient management strategies during weaning from cardiopulmonary bypass is ongoing; intravenous calcium is occasionally used as a first-line drug. The physiologic role of calcium suggests that it can support the function of the cardiovascular system during this critical period. Patients may be mildly hypocalcemic after cardiopulmonary bypass; however, this degree of hypocalcemia does not significantly impair the cardiovascular system. The transient beneficial effects of calcium administration (increase in arterial blood pressure, systemic vascular resistance, cardiac index, stroke volume, and coronary perfusion pressure) might be helpful in cases of moderate contractility reduction or vasoplegia. Nonetheless, effects on clinically relevant endpoints are unknown, and possible systemic side effects, such as transient reduction in internal mammary artery graft flow, attenuation of the effects of β-sympathomimetics, "stone heart" phenomenon, and pancreatic cellular injury, may limit the use of calcium salts. Further studies are needed to expand the understanding of the effects of calcium administration on patient outcomes.

Traumatic brain injury remains a leading cause of morbidity and mortality in children. The use of hyperosmolar therapy to offset increased intracranial pressure (ICP) is described in pediatric guidelines, yet some controversy remains regarding which option to select. A search was conducted using the PubMed, MEDLINE, Cumulative Index of Nursing and Allied Health, Academic Search Premier, PsycInfo, and Cochrane Library databases. Studies were included if they described the hyperosmolar therapy use, involved severe traumatic brain injury (TBI), and patient age was 0 to 18 years. A total of 331 studies published between 1987 and 2017 were retrieved; of these, 9 met the inclusion criteria. Included studies were evaluated for the type and concentration of hyperosmolar therapy, associated mortality outcomes, ICP and coronary perfusion pressure (CPP) measurements, concurrent medications, and reported serum sodium and serum osmolarity or osmolality values. Hypertonic saline was the most commonly reported hyperosmolar therapy. Mannitol was less studied, but collectively demonstrated a higher incidence of mortality than hypertonic saline. There were several studies that did not report monitoring outcomes associated with serum sodium and/or serum osmolarity, despite the use of hyperosmolar therapies. Inconsistencies were noted between the studies in the overall study design as well as reported monitoring parameters and length of stay. Hypertonic saline appears to be safe and efficacious at several concentrations for treatment of increased ICP associated with severe TBI in pediatric patients. The limited available data regarding the use of mannitol do not allow a strong conclusion to be made regarding its use.

Background Elevated systolic blood pressure and decreased diastolic blood pressure increase systolic load, with concurrent decrease in coronary perfusion pressure. Researches suggested a relation between elevated pulse pressure and morbidity and mortality due to cardiovascular events. This study set out to investigate whether pulse pressure is a predisposing risk factor for coronary heart disease or an aggravating risk factor in patients with coronary artery disease. Methods A total of 5,027 pressure registers were evaluated. Pulse pressure was determined invasively [...]

Aortic balloon occlusion (ABO) facilitates the success of cardiopulmonary resuscitation (CPR) in non-traumatic cardiac arrest, and is also effective in controlling traumatic hemorrhage; however, a prolonged occlusion results in irreversible organ injury and death. In this study, we investigated the effects of ABO on CPR outcomes and its optimal duration for post-resuscitation organ protection in a porcine model of traumatic cardiac arrest (TCA).Twenty-seven male domestic pigs weighing 33 ± 4 kg were utilized. Forty percent of estimated blood volume was removed within 20 min. The animals were then subjected to 5 min of untreated ventricular fibrillation and 5 min of CPR. Coincident with the start of CPR, the animals were randomized to receive either 30-min ABO (n = 7), 60-min ABO (n = 8) or control (n = 12). Meanwhile, fluid resuscitation was initiated by the infusion of normal saline with 1.5 times of hemorrhage volume in 1 h, and finished by the reinfusion of 50% of the shed blood in another 1 h. The resuscitated animals were monitored for 6 h and observed for an additional 18 h.During CPR, coronary perfusion pressure was significantly increased followed by a higher rate of resuscitation success in the 30 and 60-min ABO groups compared with the control group. However, post-resuscitation cardiac, neurologic dysfunction, and injuries were significantly milder accompanied with less renal and intestinal injuries in the 30-min ABO group than in the other two groups.In conclusion, ABO augmented the efficacy of CPR after TCA, and furthermore a 30-min ABO improved post-resuscitation cardiac and neurologic outcomes without exacerbating the injuries of kidney and intestine.

Scientific statements and publications have recommended the use of vasoconstrictors as the first-line pharmacologic choice for most cases of cardiogenic shock (CS), without the abundance of strong clinical evidence. One challenge of guidelines is that the way recommendations are stated can potentially lead to oversimplification of complex situations. Except for acute coronary syndrome with CS, in which maintenance of coronary perfusion pressure seems logical prior to revascularization, physiologic consequences of increasing afterload by use of vasoconstrictors should be analyzed. Changing the CS conceptual frame, emphasizing inflammation and other vasodilating consequences of prolonged CS, mixes causes and consequences. Moreover, the considerable interpatient differences regarding the initial cause of CS and subsequent consequences on both macro- and microcirculation, argue for a dynamic, step-by-step, personalized therapeutic strategy. In CS, vasoconstrictors should be used only after a reasoning process, a review of other possible options, and then should be titrated to reach a reasonable pressure target, while checking cardiac output and organ perfusion.

Spontaneous coronary artery dissection (SCAD) can lead to acute coronary syndrome and sudden cardiac death, particularly in young women. Observational data show that, in SCAD patients, both percutaneous coronary intervention and coronary artery bypass grafting seem to be hampered by higher technical complexity, lower success rates, and worse outcomes. As spontaneous healing is a common occurrence, expert consensus advices medical management of the acute phase, when feasible. We present the case of a young woman with SCAD of left anterior descending artery causing myocardial infarction with ST‐segment elevation. High‐anatomical complexity and unstable conditions of the patient made both medical management and immediate revascularization unfeasible options. Therefore, we decided to implant a percutaneous off‐loading mechanical support device to improve coronary perfusion pressure by unloading the left ventricle and preserve cardiac function, preventing worse complications of acute myocardial infarction. This strategy was successful in stabilizing the patient, until the definitive revascularization treatment became an option.

Objective Two-Thumb(TT) technique provides superior quality chest compressions compared with Two-Finger(TF) in an instrumented infant manikin. Whether this translates to differences in blood flow, such as carotid arterial blood flow(CABF), has not been evaluated. We hypothesized that TT-CPR generates higher CABF and Coronary Perfusion Pressure(CPP) compared with TF-CPR in a neonatal swine cardiac arrest model. Methods Twelve anesthetized & ventilated piglets were randomized after 3 min of untreated VF to receive either TT-CPR or TF-CPR by PALS certified rescuers delivering a compression rate of 100/min. The primary outcome, CABF, was measured using an ultrasound transonic flow probe placed on the left carotid artery. CPP was calculated and end-tidal CO2(ETCO2) was measured during CPR. Data(mean ± SD) were analyzed and p-value ≤0.05 was considered statistically significant. Results Carotid artery blood flow (% of baseline) was higher in TT-CPR (66.2 ± 35.4%) than in the TF-CPR (27.5 ± 10.6%) group, p = 0.013. Mean CPP (mm Hg) during three minutes of chest compression for TT-CPR was 12.5 ± 15.8 vs. 6.5 ± 6.7 in TF-CPR, p = 0.41 and ETCO2 (mm Hg) was 29.0 ± 7.4 in TT-CPR vs. 20.7 ± 5.8 in TF-CPR group, p = 0.055. Conclusion TT-CPR achieved more than twice the CABF compared with TF-CPR in a piglet cardiac arrest model. Although CPP and ETCO2 were higher during TT-CPR, these parameters did not reach statistical significance. This study provides direct evidence of increased blood flow in infant swine using TT-CPR and further supports that TT chest compression is the preferred method for CPR in infants.

BACKGROUND: Current guidelines recommend a 50 mm or greater compression depth for manual chest compression in adults. However, whether this uniform compression depth is a suitable requirement for mechanical CPR remains to be determined. We hypothesized that a relatively shallow compression depth (30 mm) would have similar hemodynamic efficacy but fewer complications versus the standard compression depth (50 mm) during mechanical cardiopulmonary resuscitation (CPR) with the miniaturized chest compressor (MCC) in a porcine model. METHODS: In the current study, we used a total of 16 domestic male pigs (38±2 kg). All pigs were exposed to 7 min of ventricular fibrillation (VF) followed by 5 min of CPR. Then the animals were randomly assigned to the shallow (30 mm) group and the standard (50 mm) group. At the second min of CPR, every pig was given epinephrine (20 µg/kg) through the femoral vein and repeated every 3 min. First defibrillation was delivered with a single 120 J shock at 5 min of CPR. Hemodynamics, carotid blood flow (CBF), end-tidal carbon dioxide (ETCO(2)), coronary perfusion pressure (CPP), intrathoracic pressure (ITP) and arterial blood gas were measured. Rib fractures and lung injuries, as indicated by ground-glass opacification (GGO), as well as intense parenchymal opacification (IPO), were assessed and calculated by quantitative computed tomography (QCT) scan. RESULTS: We found no significant differences in CPP, CBF, or ETCO(2) between the both groups throughout the CPR period. After administration of epinephrine, the CPP of all animals increased while ETCO(2) and CBF decreased during CPR. A significantly lower intrathoracic positive pressure (ITPP) and systolic artery pressure (SAP) were measured in the shallow group at the first min of CPR. However, we didn’t find remarkable differences in these values between the both groups for the next 4 min of CPR. All animals were successfully resuscitated. The shallow group had significantly lower IPO QCT scores compared with the standard group. We found no significant differences in GGO QCT scores after resuscitation between both groups. CONCLUSIONS: Relatively shallow compression depth has similar hemodynamic efficacy but fewer complications versus the standard compression depth.

Primary vasopressor efficacy of epinephrine during cardiopulmonary resuscitation (CPR) is due to its α-adrenergic effects. However, epinephrine plays β1-adrenergic actions, which increasing myocardial oxygen consumption may lead to refractory ventricular fibrillation (VF) and poor outcome. Effects of a single dose of esmolol in addition to epinephrine during CPR were investigated in a porcine model of VF with an underlying acute myocardial infarction. VF was ischemically induced in 16 pigs and left untreated for 12 min. During CPR, animals were randomized to receive epinephrine (30 µg/kg) with either esmolol (0.5 mg/kg) or saline (control). Pigs were then observed up to 96 h. Coronary perfusion pressure increased during CPR in the esmolol group compared to control (47 ± 21 vs. 24 ± 10 mmHg at min 5, p p p p

Importance Pediatric in-hospital cardiac arrest (IHCA) occurs frequently and is associated with high morbidity and mortality. The objective of this narrative review is to summarize the current knowledge and recommendations regarding pediatric IHCA and cardiopulmonary resuscitation (CPR). Observations Each year, more than 15 000 children receive CPR for cardiac arrest during hospitalization in the United States. As many as 80% to 90% survive the event, but most patients do not survive to hospital discharge. Most IHCAs occur in intensive care units and other monitored settings and are associated with respiratory failure or shock. Bradycardia with poor perfusion is the initial rhythm in half of CPR events, and only about 10% of events have an initial shockable rhythm. Pre-cardiac arrest systems focus on identifying at-risk patients and ensuring that they are in monitored settings. Important components of CPR include high-quality chest compressions, timely defibrillation when indicated, appropriate ventilation and airway management, administration of epinephrine to increase coronary perfusion pressure, and treatment of the underlying cause of cardiac arrest. Extracorporeal CPR and measurement of physiological parameters are evolving areas in improving outcomes. Structured post-cardiac arrest care focused on targeted temperature management, optimization of hemodynamics, and careful intensive care unit management is associated with improved survival and neurological outcomes. Conclusions and relevance Pediatric IHCA occurs frequently and has a high mortality rate. Early identification of risk, prevention, delivery of high-quality CPR, and post-cardiac arrest care can maximize the chances of achieving favorable outcomes. More research in this field is warranted.

Background A ‘catecholamine storm’ in a case of pheochromocytoma can lead to a transient left ventricular dysfunction similar to Takotsubo cardiomyopathy. A cardiogenic shock can thus develop, with high left ventricular end-diastolic pressure and a reduction in coronary perfusion pressure. This scenario can ultimately lead to a cardiac arrest, in which unloading the left ventricle with a peripheral left ventricular assist device (Impella®) could help in achieving the return of spontaneous circulation (ROSC). Case summary A patient affected by Takotsubo cardiomyopathy caused by a pheochromocytoma presented with cardiogenic shock that finally evolved into refractory cardiac arrest. Cardiopulmonary resuscitation was performed but ROSC was achieved only after Impella® placement. Discussion In the clinical scenario of Takotsubo cardiomyopathy due to pheochromocytoma, when cardiogenic shock develops treatment is difficult because exogenous catecholamines, required to maintain organ perfusion, could exacerbate hypertension and deteriorate the cardiomyopathy. Moreover, as the coronary perfusion pressure is critically reduced, refractory cardiac arrest could develop. Although veno-arterial extra-corporeal membrane oxygenation (va-ECMO) has been advocated as the treatment of choice for in-hospital refractory cardiac arrest, in the presence of left ventricular overload a device like Impella®, which carries fewer complications as compared to ECMO, could be effective in obtaining the ROSC by unloading the left ventricle.

Introduction: Survival rates for patients in out-of-hospital cardiac arrest have remained around 10% in the United Kingdom for the past seven years. If outcomes are to be improved, research into new methods of advanced life support is required. One such method may be ‘heads-up’ cardiopulmonary resuscitation.Methods: A systematic review of literature exploring heads-up cardiopulmonary resuscitation was conducted in an attempt to identify its effects on survival to discharge and neurological outcome.Results: A comprehensive search of CINAHL, MEDLINE and Google Scholar was undertaken. Six papers were classed as sufficiently relevant for inclusion. Included studies were generally of low quality and none studied the effect of heads-up cardiopulmonary resuscitation on out-of-hospital cardiac arrest patients. Animal studies identified a significant reduction in intracranial pressure and increase in cerebral and coronary perfusion pressure for use of augmented heads-up cardiopulmonary resuscitation in the porcine model of cardiac arrest.Conclusion: Further research is required to analyse the effects and potential benefits of augmented heads-up cardiopulmonary resuscitation in out-of-hospital cardiac arrest.

Aim Pseudo-pulseless electrical activity (pseudo-PEA) is a global hypotensive ischemic state with retained coordinated myocardial contractile activity and an organized ECG with no clinically detectable pulses. The role of standard external chest compressions (CPR) and its associated intrinsic hemodynamics remains unclear in the setting of pseudo-PEA. We undertook an experimental trial to compare epinephrine alone versus epinephrine with CPR in the treatment of pseudo-PEA. Methods Using a porcine model of hypoxic pseudo-PEA, we randomized 12 Yorkshire male swine to resuscitation with epinephrine only (control) (0.0015 mg/kg) versus epinephrine plus standard CPR (intervention). Animals who achieved return of spontaneous circulation (ROSC) were stabilized, fully recovered to hemodynamic and respiratory baseline, and rearrested up to 6 times. Primary outcome was ROSC defined as a sustained systolic blood pressure (SBP) of 60 mmHg for 2 min. Secondary outcomes included time to ROSC, coronary perfusion pressure (CoPP), and end-tidal carbon dioxide (ETCO2). Results Among 47 events of pseudo-PEA in 12 animals, we observed significantly higher proportion of ROSC when treatment included CPR (14/21 – 67%) compared to epinephrine alone (4/26 – 15%) (p = 0.0007). CoPP, aortic pressures and ETCO2 were significantly higher, and right atrial pressures were lower in the intervention group. Conclusions In a swine model of hypoxia-induced pseudo-PEA, epinephrine plus CPR was associated with improved intra-arrest hemodynamics and higher probability of ROSC. Thus, epinephrine plus CPR may be superior to epinephrine alone in the treatment of patients with pseudo-PEA.

Although progesterone has the ability to promote dilation of vascular smooth muscle, its role in coronary circulation is still poorly characterized, especially in essential hypertension and in a model of endogenous deficiency of ovarian hormones. Thus, this study evaluated the effect of progesterone treatment on endothelium-dependent coronary vascular reactivity in hypertensive (SHR) and ovariectomized rats. Adult SHR aged 8–10 weeks were divided into: SHAM, Ovariectomized (OVX) and Ovariectomized + treatment with 2 mg/kg/day of progesterone for 15 days (OVX-P4). Coronary vascular reactivity was investigated using the modified Langendorff method. After stabilization, baseline coronary perfusion pressure (CPP) was recorded and vascular reactivity to bradykinin (BK, 0.1–1000 ng) were assessed before and after infusion, either individually or in combination, with Nω-nitro-l-arginine methyl ester (l-NAME), indomethacin or clotrimazole. Scanning electron microscopy was used for qualitative analysis of the endothelium. OVX and OVX-P4 groups had a higher baseline CPP compared to that of the SHAM group. BK was able to promote vasodilation in all groups. However, relaxation to BK was less pronounced in the OVX group when compared to SHAM, with architecture loss and areas of cell atrophy having been observed. Progesterone treatment prevented this injury. Perfusion with l-NAME induced greater damage to the SHAM group, while the use of indomethacin led to a significant reduction in the vasodilator response to BK in the OVX-P4 group. Taken together, our results show that progesterone modulates endothelium-dependent coronary vasodilation in SHR ovariectomized, preventing damage caused by ovarian hormonal deficiency through a mechanism that involves prostanoid pathway.

Aim of the study Controlled sequential elevation of the head and thorax (CSE) during active compression decompression (ACD) cardiopulmonary resuscitation (CPR) with an impedance threshold device (ITD) has been shown to increase cerebral perfusion pressure and cerebral blood flow in previous animal studies as compared to the traditional supine position. The potential for this novel bundled treatment strategy to improve survival with intact neurological function is unknown. Methods Female farm pigs were sedated, intubated, and anesthetized. Central arterial and venous access were continuously monitored. Regional brain tissue perfusion (CerO2) was also measured transcutaneous. Ventricular fibrillation (VF) was induced and untreated for 10 min. Pigs were randomized to (1) Conventional CPR (C-CPR) flat or (2) ACD + ITD CSE CPR that included 2 min of ACD + ITD with the head and heart first elevated 10 and 8 cm, and then gradual elevation over 2 min to 22 and 9 cm, respectively. After 19 min of CPR, pigs were defibrillated and recovered. A veterinarian blinded to the intervention assessed cerebral performance category (CPC) at 24 h. A neurologically intact outcome was defined as a CPC score of 1 or 2. Categorical outcomes were analyzed by Fisher's exact test and continuous outcomes with an unpaired student's t-test. Results In 16 animals, return of spontaneous circulation rate was 8/8 (100%) with ACD + ITD CSE and 3/8 (25%) for C-CPR (p = 0.026). For the primary outcome of neurologically intact survival, 6/8 (75%) pigs had a CPC score 1 or 2 with ACD + ITD CSE versus 1/8 (12.5%) with C-CPR (p = 0.04). Coronary perfusion pressure (mmHg, mean ± SD) was higher with CSE at 18 min (41 ± 24 versus 10 ± 5, p = 0.004). rSO2 (%, mean ± SD) and ETCO2 (mmHg, mean ± SD) values were higher at 18 min with CSE (32 ± 9 versus 17 ± 2, p = 0.01, and 55 mmHg ± 10 versus 21 mmHg ± 4, p Conclusions The novel bundled resuscitation approach of CSE with ACD + ITD CPR increased favorable neurological survival versus C-CPR in a swine model of cardiac arrest.

Aim: Compare vasopressin to a second dose of epinephrine as rescue therapy after ineffective initial doses of epinephrine in diverse models of pediatric in-hospital cardiac arrest. Methods: 67 one- to three-month old female swine (10−30 kg) in six experimental cohorts from one laboratory received hemodynamic-directed CPR, a resuscitation method where high quality chest compressions are provided and vasopressor administration is titrated to coronary perfusion pressure (CoPP) ≥20 mmHg. Vasopressors are given when CoPP is

Intraaortic balloon pump counterpulsation is the most common form of mechanical circulatory support used in patients with myocardial ischemia and cardiogenic shock. The physiologic principles of counterpulsation include diastolic augmentation of aortic pressure and systolic reduction of left ventricular afterload, resulting in hemodynamic benefits through increased coronary perfusion pressure and improved myocardial oxygen balance in patients with myocardial ischemia. Major trials have failed to conclusively demonstrate improvements in morbidity and mortality with counterpulsation therapy for patients with acute myocardial infarction (MI), cardiogenic shock, and/or severe coronary artery disease undergoing revascularization therapy, and the debate over its applications continues. Part I of this review focuses on the history of the development of counterpulsation, technical considerations, and complications associated with its use, its physiologic effects, and evidence for its use in myocardial ischemia and cardiogenic shock.

Objectives We evaluated the feasibility of optimising coronary perfusion pressure (CPP) during cardiopulmonary resuscitation (CPR) with a closed-loop, machine-controlled CPR system (MC-CPR) that sends real-time haemodynamic feedback to a set of machine learning and control algorithms which determine compression/decompression characteristics over time. Background American Heart Association CPR guidelines (AHA-CPR) and standard mechanical devices employ a “one-size-fits-all” approach to CPR that fails to adjust compressions over time or individualise therapy, thus leading to deterioration of CPR effectiveness as duration exceeds 15–20 ​min. Methods CPR was administered for 30 ​min in a validated porcine model of cardiac arrest. Intubated anaesthetised pigs were randomly assigned to receive MC-CPR (6), mechanical CPR conducted according to AHA-CPR (6), or human-controlled CPR (HC-CPR) (10). MC-CPR directly controlled the CPR piston’s amplitude of compression and decompression to maximise CPP over time. In HC-CPR a physician controlled the piston amplitudes to maximise CPP without any algorithmic feedback, while AHA-CPR had one compression depth without adaptation. Results MC-CPR significantly improved CPP throughout the 30-min resuscitation period compared to both AHA-CPR and HC-CPR. CPP and carotid blood flow (CBF) remained stable or improved with MC-CPR but deteriorated with AHA-CPR. HC-CPR showed initial but transient improvement that dissipated over time. Conclusion Machine learning implemented in a closed-loop system successfully controlled CPR for 30 ​min in our preclinical model. MC-CPR significantly improved CPP and CBF compared to AHA-CPR and ameliorated the temporal haemodynamic deterioration that occurs with standard approaches.

Introduction Amiodarone represents the most widely used antiarrhythmic drug, even though it has been shown that it has negative inotropic and lusitropic effect in healthy hears. On the other hand, dronedarone reduces the risk of recurrent atrial fibrillation, but with increased early mortality related to the worsening of heart failure. However, the mechanisms responsible for these fatal outcomes remain unclear and require further examinations. Purpose To investigate acute, direct effects of Dronedarone and Amiodarone on cardiac contractility, coronary flow and oxidative stress parameters in isolated rat heart with hypertension. Methods The present study was carried out on 18 isolated hearts of spontaneously hypertensive Wistar Kyoto male rats (6 weeks old, bodyweight 200 ± 10 g). After isolation, all hearts were retrogradely perfused according to Langendorff technique with a gradually increment of coronary perfusion pressure (CPP from 40 to 120 cm H2O) and randomly divided into 3 groups: Control (n = 6), Amiodarone (n = 6, isolated hearts perfused with Amiodarone in dose of 3 umol), Dronedarone (n = 6, isolated hearts perfused with Dronedarone in dose of 1.8 umol). During ex vivo protocol continuously were registered cardiac contractility parameters and coronary flow, while from collected coronary venous effluent markers of oxidative stress were measured. All hearts were then fixated and stained with Hematoxylin/eosin. Results Dronedarone severely depressed the function of all cardiodynamic parameters of the heart compared with Amiodarone or Control while Amiodarone intensified the function of the isolated rat heart with hypertension compared to Control (dp/dt max mmHg/s at coronary perfusion pressure 120cmH2O Dronedarone vs. Amiodarone vs. Control 579.733 ± 202.27 vs. 3063.65 ± 467.93 vs. 2682.88 ± 368.75; p Conclusions Acute administration of Dronedarone depresses cardiac function in isolated, working rat heart with hypertension, with decreasing the NO2- levels, increasing the level of H2O2 and enhanced structural changes when compared to Amiodarone.

In pre-hypertension, moderate control of blood pressure (BP) can be obtained by a nutritional approach. The effects of a diet enriched with defatted larvae of the mealworm Tenebrio molitor (Coleoptera: Tenebrionidae) (TM) endowed with ACE inhibitory activity was studied in both spontaneously hypertensive rats (SHR) and in the age-matched normotensive Wistar Kyoto strain. These were fed for 4 weeks with standard laboratory rodent chow supplemented with or without TM or captopril. In SHR, the TM diet caused a significant reduction in BP, heart rate and coronary perfusion pressure, as well as an increase in red blood cell glutathione/glutathione disulphide ratio. Rat brain slices of SHR were more resistant to oxidative stress and contained lower levels of inflammatory cytokines, while vascular and liver enzyme-activities were not affected. These results suggest that TM can be considered a new functional food that can lower BP in vivo and thus control cardiovascular-associated risk factors such as hypertension.

Aims The described association of low diastolic blood pressure (DBP) with increased cardiovascular outcomes could be due to reduced coronary perfusion or is simply due to reverse causation. If DBP is physiologically relevant, coronary reperfusion after myocardial infarction (MI) might influence DBP–risk association. Methods and results The relation of achieved DBP with cardiovascular death or cardiovascular hospitalization, cardiovascular death, and all-cause death was explored in 5929 patients after acute myocardial infarction (AMI) with impaired left ventricular function, signs and symptoms of heart failure, or diabetes in the EPHESUS trial according to their reperfusion status. Cox regression models were used to assess the impact of reperfusion status on the association of DBP and systolic blood pressure (SBP) with outcomes in an adjusted fashion. In patients without reperfusion, lower DBP Conclusion Patients after AMIs with a low DBP had an increased risk, which was sensitive to reperfusion therapy. Low blood pressure after MI identifies in patients with particular higher risk. These data support the hypothesis that low DBP in patients with stenotic coronary lesions is associated with risk, potentially involving coronary perfusion pressure and the recommendations provided by guidelines suggesting lower DBP boundaries for these high-risk patients.

Background Epinephrine increases the rate of return of spontaneous circulation. However, it increases severity of postresuscitation myocardial and cerebral dysfunction and reduces duration of survival. We investigated the effects of aortic infused polyethylene glycol, 20 000 molecular weight ( PEG ‐20k) during cardiopulmonary resuscitation on coronary perfusion pressure, postresuscitation myocardial and cerebral function, and duration of survival in a rat model of cardiac arrest. Methods and Results Twenty‐four male rats were randomized into 4 groups: (1) PEG ‐20k, (2) epinephrine, (3) saline control–intravenous, and (4) saline control–intra‐aortic. Cardiopulmonary resuscitation was initiated after 6 minutes of untreated ventricular fibrillation. In PEG ‐20k and Saline‐A, either PEG ‐20k (10% weight/volume in 10% estimated blood volume infused over 3 minutes) or saline was administered intra‐aortically after 4 minutes of precordial compression. In epinephrine and placebo groups, either epinephrine (20 μg/kg) or saline placebo was administered intravenously after 4 minutes of precordial compression. Resuscitation was attempted after 8 minutes of cardiopulmonary resuscitation. Sublingual microcirculation was measured at baseline and 1, 3, and 5 hours after return of spontaneous circulation. Myocardial function was measured at baseline and 2, 4, and 6 hours after return of spontaneous circulation. Neurologic deficit scores were recorded at 24, 48, and 72 hours after return of spontaneous circulation. Aortic infusion of PEG ‐20k increased coronary perfusion pressure to the same extent as epinephrine. Postresuscitation sublingual microcirculation, myocardial and cerebral function, and duration of survival were improved in PEG ‐20k ( P P Conclusions Aortic infusion of PEG ‐20k during cardiopulmonary resuscitation increases coronary perfusion pressure to the same extent as epinephrine, improves postresuscitation myocardial and cerebral function, and increases duration of survival in a rat model of cardiac arrest.

The aim of this study was to investigate the influence of enhanced external counterpulsation (EECP) on the cardiac function of beagle dogs after prolonged ventricular fibrillation. Twenty-four adult male beagles were randomly divided into control and EECP groups. Ventricular fibrillation was induced in the animals for 12 min, followed by 2 min of cardiopulmonary resuscitation. They then received EECP therapy for 4 h (EECP group) or not (control group). The hemodynamics was monitored using the PiCCO2 system. Blood gas and hemorheology were assessed at baseline and at 1, 2, and 4 h after return of spontaneous circulation (ROSC). The myocardial blood flow (MBF) was quantified by 18F-flurpiridaz PET myocardial perfusion imaging at baseline and 4 h after ROSC. Survival time of the animals was recorded within 24 h. Ventricular fibrillation was successfully induced in all animals, and they achieved ROSC after cardiopulmonary resuscitation. Survival time of the control group was shorter than that of the EECP group [median of 8 h (min 8 h, max 21 h) vs median of 24 h (min 16 h, max 24 h) (Kaplan Meyer plot analysis, P=0.0152). EECP improved blood gas analysis findings and increased the coronary perfusion pressure and MBF value. EECP also improved the cardiac function of Beagles after ROSC in multiple aspects, significantly increased blood flow velocity, and decreased plasma viscosity, erythrocyte aggregation index, and hematocrit levels. EECP improved the hemodynamics of beagle dogs and increased MBF, subsequently improving cardiac function and ultimately improving the survival time of animals after ROSC.

Background The aim of this study was to investigate whether 33% duty cycle increases end-tidal carbon dioxide (ETCO2) level, a surrogate measurement for cardiac output during cardiopulmonary resuscitation (CPR), compared with 50% duty cycle. Methods Six pigs were randomly assigned to the DC33 or DC50 group. After 3 min of induced ventricular fibrillation (VF), CPR was performed for 5 min with 33% duty cycle (DC33 group) or with 50% duty cycle (DC50 group) (phase I). Defibrillation was delivered until return of spontaneous circulation (ROSC) thereafter. After 30 min of stabilization, the animals were re-assigned to the opposite groups. VF was induced again, and CPR was performed (phase II). The primary outcome was ETCO2 during CPR, and the secondary outcomes were coronary perfusion pressure (CPP), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and right atrial pressure (RAP). Results Mean ETCO2 was higher in the DC33 group compared with the DC50 group (22.5 mmHg vs 21.5 mmHg, P = 0.018). In a linear mixed model, 33% duty cycle increased ETCO2 by 1.0 mmHg compared with 50% duty cycle (P < 0.001). ETCO2 increased over time in the DC33 group [0.6 mmHg/min] while ETCO2 decreased in the DC50 group [-0.6 mmHg/min] (P < 0.001). Duty cycle of 33% increased SAP (6.0 mmHg, P < 0.001), DAP (8.9 mmHg, P < 0.001) RAP (2.6 mmHg, P < 0.001) and CPP (4.7 mmHg, P < 0.001) compared with the duty cycle of 50%. Conclusion Duty cycle of 33% increased ETCO2, a surrogate measurement for cardiac output during CPR, compared with duty cycle of 50%. Moreover, ETCO2 increased over time during CPR with 33% duty cycle while ETCO2 decreased with 50% duty cycle.

Aim To investigate the molecular mechanisms and cellular signaling pathways involved in the activation of TP receptors and the consequent induction of contractile responses in coronary arteries of renal hypertensive (2K-1C) rats. Methods and results The coronary perfusion pressure (CPP) was lower in 2K-1C rats during increased coronary flow as measured by the Langendorff technique. The coronary contraction and relaxation were evaluated by vascular reactivity studies, and the molecular mechanisms were investigated on the basis of the protein expression of TP receptors, Cav-1, eNOS, COX-1, and COX-2, as measured by Western blot. The levels of eicosanoids were determined by ELISA immunoassay and analyzed by reverse-phase HPLC coupled to electrospray ionization mass spectrometry (HPLC-MS/MS). The metabolites from NO production were evaluated by the Griess reaction. The coronary arteries of 2K-1C rats expressed COX-2 to a larger extent and TP receptors to a lesser extent than the coronary arteries of normotensive (2K) rats. Selective COX-1 and non-selective COX inhibitors reversed the reduction in the contraction induced by TP receptors in the coronary arteries of 2K-1C rats. U46619, an agonist of TP receptors, induced a contractile response that was relaxed by acetylcholine (ACh). In the coronary arteries of 2K-1C rats, this ACh-induced relaxation depended on COX. The activation of TP receptors increased the production of PGI2 in the coronary arteries of 2K-1C rats. The results demonstrated that increased COX signaling in the coronary arteries of 2K-1C rats mediated the low levels of CPP, the contraction induced by the activation of TP receptors, and the endothelium-dependent relaxation. The vasodilator PGI2 seemed to be the major product. Conclusion Activation of TP receptors increases production of PGI2 in coronary arteries of 2K-1C rats.

Background: There is a conflict in the superiority of each of the vasopressin and epinephrine compared to the other. Vasopressin has a vasoconstrictive action that results in an increase of the coronary perfusion pressure. Due to the expensive and sometimes scarce of vasopressin in most hospitals, this study aims to evaluate the response rate of vasopressin compared with epinephrine, in return of ROSC. Methods: In this descriptive-analytical study all patients in the emergency medicine department were enrolled in the study suffered a cardiopulmonary arrest and resuscitation will be done instantly for them (According to the guidelines AHA 2010). Their data were extracted from the hospital records and the success rate of recovery, 3-month survival and complications in patients recovering from the drug used during the CPR were analyzed. Results: A total of 61 patients record were analyzed. 31 patients had received epinephrine alone and 30 patients received a combination of epinephrine and vasopressin. No significant difference was observed between the two groups in terms of sex, sepsis, hypovolemia, renal failure, cancers, drug toxicity, brady, dysrhythmia, PEA, VT, VF, defibrillator, duration of CPR and three month outcome. The mean time of CPR in combination of epinephrine and vasopressin group was 27.26±12.72 and the mean time of CPR in epinephrine group was 27.24±13.510 (p-value= 0.99).Conclusion: Among patients with in-hospital cardiopulmonary arrest in this study no statistically significant difference was obtained between the results of treatment with epinephrine alone and combination of epinephrine and vasopressin.

Taken into consideration that molecular and cellular mechanisms involved in cardiotoxicity are still not clear the aim of this study was to compare the production of oxidative stress parameters in the isolated rat heart between animals chronically treated with cisplatin and saline. The hearts of male Wistar albino rats (n = 24, 12 per group, age 8 weeks, body mass 250±50 g) were excised and perfused according to the Langendorff technique at gradually increased coronary perfusion pressures (40-120 cm H2O). We followed the production of superoxide anion radicals, hydrogen peroxide, and nitrites and also index of lipid peroxidation during the changes of coronary perfusion pressure (CPP) (from 40 to 120 cm H2O) in coronary venous effluent. Modifications CPP were performed in order to determined if oxidative stress is involved in coronary endothelium response in conditions of hypoxia (lower than 60 cm H2O) and hyperoxia (higher than 80 cm H2O).Based on the results of this research we can conclude that with enhancement of CPP the values of oxidative stress statistically increased. However, this increment is more prominent in control group as a result of preserved endothelium and its more powerful response to hyperoxia. On the other hand, damaged endothelium of cisplatin-treated animals had weaker response to hyperoxia, and also lower antioxidant capacity.

Only one in ten patients survives cardiac arrest (CA), underscoring the need to improve CA management. Isoflurane has shown cardio- and neuroprotective effects in animal models of ischemia-reperfusion injury. Therefore, the beneficial effect of isoflurane should be tested in an experimental CA model. We hypothesize that isoflurane anesthesia improves short-term outcome following resuscitation from CA compared with a subcutaneous fentanyl/fluanisone/midazolam anesthesia. Male Sprague-Dawley rats were randomized to anesthesia with isoflurane ( n = 11) or fentanyl/fluanisone/midazolam ( n = 11). After 10 min of asphyxial CA, animals were resuscitated by mechanical chest compressions, ventilations, and epinephrine and observed for 30 min. Hemodynamics, including coronary perfusion pressure, systemic O2consumption, and arterial blood gases, were recorded throughout the study. Plasma samples for endothelin-1 and cathecolamines were drawn before and after CA. Compared with fentanyl/fluanisone/midazolam anesthesia, isoflurane resulted in a shorter time to return of spontaneous circulation (ROSC), less use of epinephrine, increased coronary perfusion pressure during cardiopulmonary resusitation, higher mean arterial pressure post-ROSC, increased plasma levels of endothelin-1, and decreased levels of epinephrine. The choice of anesthesia did not affect ROSC rate or systemic O2consumption. Isoflurane reduces time to ROSC, increases coronary perfusion pressure, and improves hemodynamic function, all of which are important parameters in CA models.NEW & NOTEWORTHY The preconditioning effect of volatile anesthetics in studies of ischemia-reperfusion injury has been demonstrated in several studies. This study shows the importance of anesthesia in experimental cardiac arrest studies as isoflurane raised coronary perfusion pressure during resuscitation, reduced time to return of spontaneous circulation, and increased arterial blood pressure in the post-cardiac arrest period. These effects on key outcome measures in cardiac arrest research are important in the interpretation of results from animal studies.

ATP-sensitive potassium (KATP) channels are widely expressed in the cardiovascular system, where they regulate a range of biological activities by linking cellular metabolism with membrane excitability. KATP channels in vascular smooth muscle have a well-defined role in regulating vascular tone. KATP channels are also thought to be expressed in vascular endothelial cells, but their presence and function in this context are less clear. As a result, we aimed to investigate the molecular composition and physiological role of endothelial KATP channels. We first generated mice with an endothelial specific deletion of the channel subunit Kir6.1 (eKO) using cre-loxP technology. Data from qRT-PCR, patch clamp, ex vivo coronary perfusion Langendorff heart experiments, and endothelial cell Ca2+ imaging comparing eKO and wild-type mice show that Kir6.1-containing KATP channels are indeed present in vascular endothelium. An increase in intracellular [Ca2+], which is central to changes in endothelial function such as mediator release, at least partly contributes to the endothelium-dependent vasorelaxation induced by the KATP channel opener pinacidil. The absence of Kir6.1 did not elevate basal coronary perfusion pressure in eKO mice. However, vasorelaxation was impaired during hypoxia in the coronary circulation, and this resulted in greater cardiac injury during ischemia–reperfusion. The response to adenosine receptor stimulation was impaired in eKO mice in single cells in patch clamp recordings and in the intact coronary circulation. Our data support the existence of an endothelial KATP channel that contains Kir6.1, is involved in vascular reactivity in the coronary circulation, and has a protective role in ischemia reperfusion.

Background: A compression-ventilation (C:V) ratio of 30:2 is recommended for adult cardiopulmonary resuscitation (CPR) by the current American Heart Association (AHA) guidelines. However, continuous chest compression (CCC) is an alternative strategy for CPR that minimizes interruption especially when an advanced airway exists. In this study, we investigated the effects of 30:2 mechanical CPR when compared with CCC in combination with regular ventilation in a porcine model. Methods: Sixteen male domestic pigs weighing 39±2 kg were utilized. Ventricular fibrillation was induced and untreated for 7 min. The animals were then randomly assigned to receive CCC combined with regular ventilation (CCC group) or 30:2 CPR (VC group). Mechanical chest compression was implemented with a miniaturized mechanical chest compressor. At the same time of beginning of precordial compression, the animals were mechanically ventilated at a rate of 10 breaths-per-minute in the CCC group or with a 30:2 C:V ratio in the VC group. Defibrillation was delivered by a single 150 J shock after 5 min of CPR. If failed to resuscitation, CPR was resumed for 2 min before the next shock. The protocol was stopped if successful resuscitation or at a total of 15 min. The resuscitated animals were observed for 72 h. Results: Coronary perfusion pressure, end-tidal carbon dioxide and carotid blood flow in the VC group were similar to those achieved in the CCC group during CPR. No significant differences were observed in arterial blood gas parameters between two groups at baseline, VF 6 min, CPR 4 min and 30, 120 and 360 min post-resuscitation. Although extravascular lung water index of both groups significantly increased after resuscitation, no distinct difference was found between CCC and VC groups. All animals were successfully resuscitated and survived for 72 h with favorable neurologic outcomes in both groups. However, obviously more numbers of rib fracture were observed in CCC animals in comparison with VC animals Conclusions: There was no difference in hemodynamic efficacy and gas exchange during and after resuscitation, therefore identical 72 h survival with intact neurologic function was observed in both VC and CCC groups. However, the incidence of rib fracture increases during the mechanical CPR strategy of CCC combined with regular ventilations.

Compared with age-matched men, premenopausal women are largely protected from coronary artery disease, a difference that is lost after menopause. The effects of oestrogens are mediated by the activation of nuclear receptors (ERα and ERβ) and by the G protein-coupled oestrogen receptor (GPER). This study aims to evaluate the potential role of GPER in coronary circulation in female and male rats. The baseline coronary perfusion pressure (CPP) and the concentration–response curve with a GPER agonist (G-1) were evaluated in isolated hearts before and after the blockade of GPER. GPER, superoxide dismutase (SOD-2), catalase and gp91phox protein expression were assessed by Western blotting. Superoxide production was evaluated ‘in situ’ via dihydroethidium fluorescence (DHE). GPER blockade significantly increased the CPP in both groups, demonstrating the modulation of coronary tone by GPER. G-1 causes relaxation of the coronary bed in a concentration-dependent manner and was significantly higher in female rats. No differences were detected in GPER, SOD-2 and catalase protein expression. However, gp91phox expression and DHE fluorescence were higher in male rats, indicating elevated superoxide production. Therefore, GPER plays an important role in modulating coronary tone and reactivity in female and male rats. The observed differences in vascular reactivity may be related to the higher superoxide production in male rats. These findings help to elucidate the role of GPER-modulating coronary circulation, providing new information to develop a potential therapeutic target for the treatment of coronary heart disease.