Organ Perfusion Research Articles

Cardiopulmonary Resuscitation Education in United States Schools: Shortcomings and Future Directions.

Cardiopulmonary resuscitation (CPR) is a lifesaving procedure that is performed during a cardiac arrest. CPR consists of chest compressions, rescue breaths, and the usage of an automated external defibrillator (AED) based on availability. Performance of CPR can greatly increase the chances of survival by enabling the manual perfusion of vital organs in lieu of the heart's normal function. Despite extensive studies demonstrating the efficacy and necessity of CPR in an emergency, most of the public across the United States is ill-equipped and/or educated on how to perform it. While there may be other contributing factors, the lack of CPR education across schools in the United States almost certainly furthers the CPR illiteracy of the general population. Although states require some degree of CPR training, the level of education that students receive varies widely across communities and school districts, largely dictated by the available funding for training courses. Despite the lack of CPR education in the United States, studies conducted abroad have shown the efficacy of a CPR course in preparing students to respond in emergencies-lending hope to mending the current situation in the United States. In this article, we analyze legislation dictating CPR instruction and hypothesize ways in which states' Department of Education might be able to promote education and hands-on experience for students across all ages of schooling. Ultimately, we hope to highlight the importance and feasibility of preparing the next generation of citizens across the United States to respond when their name is called upon in an emergency.

Preserving flow, saving lives: Successful treatment of aortic valve failure in acute myocardial infarction without flow down-regulation using ECMO - a case report and mini review.

Direct percutaneous coronary intervention (PPCI) has significantly reduced cardiac mortality in patients with acute myocardial infarction (AMI), but the mortality rate remains high for those who develop cardiogenic shock (CS), reaching 40% to 50%. Veno-arterial extracorporeal membrane oxygenation (V-A ECMO) provides robust hemodynamic support and oxygen delivery for AMI patients with refractory CS, ensuring adequate organ perfusion and oxygen supply. However, there is currently no standardized optimal Mean Arterial Pressure (MAP) range during V-A ECMO support. Achieving the proper MAP is crucial for adequate myocardial perfusion, cardiac function recovery, successful weaning off of V-A ECMO, and improving long-term outcomes. In this case study, we successfully treated a 55-year-old man with AMI and refractory cardiogenic shock using V-A ECMO. By adjusting ECMO blood flow and employing hemodynamic strategies, including vasoactive drugs, we optimized the MAP, leading to improved cardiac function and successful weaning off of V-A ECMO. This presents a potential opportunity for MAP optimization under ECMO support in patients with acute myocardial infarction and cardiogenic shock.

Role of multilayer flow modulator stents in the treatment of arterial aneurysms.

Arterial aneurysms remain a significant public health problem because they often result in death when ruptured; therefore, they require immediate medical treatment. Endovascular aneurysm repair (EVAR) has recently become the primary treatment option, owing to the fewer side effects compared to those with open surgery. However, stents used for conventional EVAR often cause side-branch occlusion, which alters the perfusion of vital organs. Recently, multilayer flow modulator (MFM) stents have been used as a new treatment for arterial aneurysms. These stents appear to be feasible owing to their unique design consisting of an uncoated three-dimensionally braided multilayered structure. MFM stents generally remodulate laminar flow and reduce the flow velocity in the aneurysmal sac, leading to thrombosis, which causes the aneurysm to shrink over time. Thus, they reduce the risk of mortality. Moreover, they reduce morbidity by preserving the side-branch blood flow. They can be easily applied to complex aneurysms and are ready to use without customization, which shortens the waiting time for interventions. This study aimed to evaluate the role of MFM stents in the treatment of arterial aneurysms based on available data.

Understanding and addressing the cholera outbreak in Zambian communities

Cholera is a bacterial infection caused by the Vibrio cholera bacterium, primarily transmitted through contaminated water and food. The effects of cholera on health can be severe and potentially life-threatening. The hallmark symptom of cholera is acute watery diarrhea, which can lead to rapid dehydration and electrolyte imbalance. As the body loses large amounts of fluid and essential salts, individuals with cholera often experience intense thirst, dry mucous membranes, sunken eyes, and lethargy. If left untreated, the dehydration can progress rapidly, causing a dangerous condition known as choleric dehydration and in most cases death. Hence, the study was conducted to analyze the effects of cholera on health in selected communities of Lusaka district in Zambia. The study employed both qualitative and quantitative methods and a descriptive survey design that sampled 42 participants purposively and conveniently. Data was obtained from the respondents by means of questionnaires and record reading. The data was analyzed by the use of software; Statistical Package for Social Sciences (version 26) and Microsoft Excel (version 16). Frequency tables, graphs, figures, and pie charts were also used to analyze the data. The findings revealed that the effect of cholera on health extends beyond dehydration, affecting various organ systems. Severe cases may lead to hypovolemic shock, characterized by a significant drop in blood pressure and inadequate perfusion of organs. The study also found that Cholera outbreaks pose significant public health challenges, particularly in areas with inadequate sanitation and limited access to clean water. The study therefore recommended that since cholera is highly contagious, primarily through contaminated water and food, those affected should be isolated to prevent the spread of the bacteria. Additionally, Proper hygiene, such as regular handwashing, is essential to reduce the risk of transmission.

Multiple Cardiac Diseases Involving the Aortic Arch: Beating Heart Debranching, and Normothermic Arch Replacement: A Case Series

(1) Background: Conventional open surgery is still the gold standard for aortic arch disease, and despite recent developments in optimizing strategies for neuroprotection, distal organ perfusion, and myocardial protection, aortic arch replacement is still associated with high morbidity and mortality rates. (2) Methods: We present our case series of 12 patients undergoing surgical management of multiple cardiac diseases involving the aortic arch. In this single-center study, we report our initial experience over a five-year period (from December 2018 to October 2023) with the use of a “debranching first” technique for the supra-aortic vessels of a beating heart, followed by the cardiac step addressing proximal diseases, and a final distal step treating the aortic arch. This strategy aims to minimize cardiac, cerebral, and peripheral ischemia. (3) Results: Six patients underwent aortic root replacement with either Bentall (n = 4) or valve-sparing aortic root (David procedure) (n = 2). The mean nasopharyngeal temperature was 34 °C and the mean cardiocirculatory arrest was 14.3 min. The early mortality was 8.3% (1 patient); no patient experienced a permanent neurologic event. (4) Conclusions: In patients with complex aortic disease and concomitant cardiac disease, this approach reduces the need for hypothermia and decreases cardiopulmonary bypass time and myocardial arrest time and therefore could represent a valid surgical option, even in high-risk patients.

Microvascular Capillary and Precapillary Cardiovascular Disturbances Strongly Interact to Severely Affect Tissue Perfusion and Mitochondrial Function in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Evolving from the Post COVID-19 Syndrome.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a frequent, debilitating and still enigmatic disease. There is a broad overlap in the symptomatology of ME/CFS and the Post-COVID-19 Syndrome (PCS). A fraction of the PCS patients develop the full clinical picture of ME/CFS. New observations in microvessels and blood from patients suffering from PCS have appeared and include microclots and malformed pathological blood cells. Capillary blood flow is impaired not only by pathological blood components but also by prothrombotic changes in the vascular wall, endothelial dysfunction, and the expression of adhesion molecules in the capillaries. These disturbances can finally cause a low capillary flow and even capillary stasis. A low cardiac stroke volume due to hypovolemia and the inability of the capacitance vessels to adequately constrict to deliver the necessary cardiac preload generate an unfavorable low precapillary perfusion pressure. Furthermore, a predominance of vasoconstrictor over vasodilator influences exists, in which sympathetic hyperactivity and endothelial dysfunction play a strong role, causing the constriction of resistance vessels and of precapillary sphincters, which leads to a fall in capillary pressure behind the sphincters. The interaction of these two precapillary cardiovascular mechanisms causing a low capillary perfusion pressure is hemodynamically highly unfavorable in the presence of a primary capillary stasis, which is already caused by the pathological blood components and their interaction with the capillary wall, to severely impair organ perfusion. The detrimental coincidence of microcirculatory and precapillary cardiovascular disturbances may constitute the key disturbance of the Post-COVID-19 syndrome and finally lead to ME/CFS in predisposed patients because the interaction causes a particular kind of perfusion disturbance-capillary ischemia/reperfusion-which has a high potential of causing mitochondrial dysfunction by inducing sodium- and calcium-overload in skeletal muscles. The latter, in turn, worsens the vascular situation through the generation of reactive oxygen species to close a vicious cycle from which the patient can hardly escape.

Effect of Respiratory Failure on Peripheral and Organ Perfusion Markers in Severe COVID-19: A Prospective Cohort Study.

Microvascular dysfunction and inflammation caused by COVID-19 disrupt organ function. The study aimed to investigate the association between the severity of SARS-CoV-2 pneumonia and peripheral and organ perfusion as a consequence of altered microcirculation. A total of 116 patients hospitalized due to severe COVID-19 were enrolled in the study. On admission, the patients underwent a Capillary Refill Time (CRT) examination, finger oxygen saturation measurement, thermal imaging of the hand (FIT), and a kidney Doppler ultrasound. Medical data were collected from the medical history. From the evaluated perfusion parameters, only renal cortex perfusion (RCP) was substantially correlated with the CT score (p < 0.010). The peripheral perfusion parameters of Sat., FIT, CRT, and RCP correlated with the ARDS stages (p = 0.0021; p = 0.038; p < 0.0006; p < 0.0002, respectively). The Oxygenation Ratio value (p < 0.001) was significantly associated with all the perfusion parameters (saturation, CRT, FIT, and RCP) in the multivariable regression analysis model. According to the stepwise retrograde regression analysis, RCP was an independent parameter linked with the Oxygenation Ratio (p < 0.001). Severe COVID-19 can result in microvascular dysfunction influencing peripheral and organ perfusion, which can be measured with various methods. The staging of COVID-19 assessed by CT and the Oxygenation Ratio correlates with RCP, CRT, FIT, and oxygen saturation.

Appropriate timing of veno-arterial extracorporeal membrane oxygenation initiation after cardiac surgery

BackgroundVeno-arterial extracorporeal membrane oxygenation (VA-ECMO) can be initiated during cardiac surgery or later in ICU according to the hemodynamic profile and organ perfusion. Our aim was to study the appropriate timing of post-cardiotomy ECMO (PC-ECMO) initiation. We retrospectively analyzed 152 adult patients supported with PC-ECMO in our cardiac center between 2016 and 2022. The patients were divided into two groups: the intra-operative ECMO and the postoperative ECMO groups. The primary outcome was all-and-on-ECMO hospital mortality. The secondary outcomes included ECMO duration, new need for dialysis, cerebrovascular stroke, and length of ICU stay.ResultsOur cohort analysis revealed that 81(53.3%) patients were intra-operatively supported with VA-ECMO while 71(46.7%) patients were postoperatively supported in ICU. The postoperative ECMO group had significantly lesser SAVE score (p = 0.001), higher SAVE risk classes (p < 0.001), and higher SOFA score (p = 0.008) compared to the intra-operative ECMO group. The postoperative ECMO group had significantly more frequent hospital mortality (p = 0.003), on-ECMO mortality (p = 0.006), cerebrovascular stroke (p = 0.034), acute renal failure requiring dialysis (p < 0.001), and lesser lactate clearance at 12 h (p = 0.016) and at 24 h (p = 0.023) compared to the intra-operative group. There were statistically insignificant differences between the two groups regarding post-ECMO hospital mortality, cerebral bleeding, limb ischemia, ECMO, and ICU duration. Postponed postoperative ECMO insertion was associated with an increased risk of death (HR 1.628, 95%CI 1.102–2.403, p =0.014) with cox-proportional hazard regression. Logistic multivariable regression showed that atrial fibrillation (OR 6.2, 95% CI 2.71–61.84, p = 0.002), initial SOFA score (OR 1.46, 95% CI 1.041–3.83, p = 0.001), and postoperative ECMO insertion (OR 1.93, 95% CI 1.04–8.73, p = 0.031) were the predictors of hospital mortality.ConclusionsPostponed ECMO insertion in critically sick patients was associated with increased mortality after cardiac surgery. Early intra-operative initiation of PC-ECMO may have the potential to improve outcomes after cardiac surgeries.

Non-invasive assessment of sublingual microcirculation using flow derived from green light PPG: evaluation and reference values.

The study of sublingual microcirculation offers valuable insights into vascular changes and overcomes some limitations of peripheral microcirculation assessment. Videomicroscopy and pulse oximetry have been used to assess microcirculation, providing insights into organ perfusion beyond macrohemodynamics parameters. However, both techniques have important limitations that preclude their use in clinical practice. To address this, we propose a non-invasive approach using photoplethysmography (PPG) to assess microcirculation. Two experiments were performed on different samples of 31 subjects. First, multi-wavelength, finger PPG signals were compared before and while applying pressure on the sensor to determine if PPG signals could detect changes in peripheral microcirculation. For the second experiment, PPG signals were acquired from the ventral region of the tongue, aiming to assess the microcirculation through features calculated from the PPG signal and its first derivative. In experiment 1, 13 out of 15 features extracted from green PPG signals showed significant differences () before and while pressure was applied to the sensor, suggesting that green light could detect flow distortion in superficial capillaries. In experiment 2, 15 features showed potential application of PPG signal for sublingual microcirculation assessment. The PPG signal and its first derivative have the potential to effectively assess microcirculation when measured from the fingertip and the tongue. The assessment of sublingual microcirculation was done through the extraction of 15 features from the green PPG signal and its first derivative. Future studies are needed to standardize and gain a deeper understanding of the evaluated features.

High-throughput CRISPR technology: a novel horizon for solid organ transplantation.

Organ transplantation is the gold standard therapy for end-stage organ failure. However, the shortage of available grafts and long-term graft dysfunction remain the primary barriers to organ transplantation. Exploring approaches to solve these issues is urgent, and CRISPR/Cas9-based transcriptome editing provides one potential solution. Furthermore, combining CRISPR/Cas9-based gene editing with an ex vivo organ perfusion system would enable pre-implantation transcriptome editing of grafts. How to determine effective intervention targets becomes a new problem. Fortunately, the advent of high-throughput CRISPR screening has dramatically accelerated the effective targets. This review summarizes the current advancements, utilization, and workflow of CRISPR screening in various immune and non-immune cells. It also discusses the ongoing applications of CRISPR/Cas-based gene editing in transplantation and the prospective applications of CRISPR screening in solid organ transplantation.

Serum CIRP increases the risk of acute kidney injury after cardiac surgery.

Acute kidney injury (AKI) is a frequent perioperative complication. The underlying mechanisms of cardiac surgery-associated AKI are still not completely elucidated. Cold-induced RNA-binding protein (CIRP) has been subsequently found to be regulated by various stress conditions. During cardiac surgery and cardiopulmonary bypass (CPB), the host is subjected to hypothermia and inadequate organ perfusion, resulting in an upregulation of CIRP secretion. The aim of this study is to evaluate the role of elevated extracellular CIRP level as a contributing factor in the development of AKI. A total of 292 patients who underwent cardiac surgery were retrospectively enrolled and their serum samples were collected preoperative and postoperative. Demographic data, intraoperative data, in-hospital outcomes, and the occurrence of AKI were also collected for the patients. The correlation between CIRP and intraoperative procedures, as well as its association with postoperative outcomes were analyzed. In multivariable analysis, higher ΔCIRP (p = 0.036) and body mass index (p = 0.015) were independent risk factors for postoperative AKI. Meanwhile, patients with postoperative AKI exhibited lower survival rate in 2-year follow-up (p = 0.008). Compared to off-pump coronary artery bypass grafting surgery, patients who underwent on-pump coronary artery bypass grafting, valve surgery, aortic dissection and other surgery showed higher ΔCIRP, measuring 1,093, 666, 914 and 258 pg/mL, respectively (p < 0.001). The levels of ΔCIRP were significantly higher in patients who underwent CPB compared to those who did not (793.0 ± 648.7 vs. 149.5 ± 289.1 pg/mL, p < 0.001). Correlation analysis revealed a positive correlation between ΔCIRP levels and the duration of CPB (r = 0.502, p < 0.001). Patients with higher CIRP levels are at greater risk of postoperative AKI (OR: 1.67, p = 0.032), especially the stage 2-3 AKI (OR: 2.11, p = 0.037). CIRP secretion increases with prolonged CPB time after cardiac surgery, and CIRP secretion is positively correlated with the duration of CPB. Cardiac surgeries with CPB exhibited significantly higher levels of CIRP compared to non-CPB surgeries. Elevation of CIRP level is an independent risk factor for the incidence of AKI, especially the severe AKI, and were associated with adverse in-hospital outcomes.

СЕРИЯ КЛИНИЧЕСКИХ СЛУЧАЕВ ПРИМЕНЕНИЯ ЭКСТРАКОРПОРАЛЬНОЙ МЕМБРАННОЙ ОКСИГЕНАЦИИ ПРИ ВЫПОЛНЕНИИ ЧКВ ВЫСОКОГО РИСКА

Introduction. Percutaneous coronary interventions (PCI) have become increasingly intricate, particularly considering patient comorbidities. The simultaneous or staged coronary artery stenting in patients with ST-segment elevation myocardial infarction (STEMI) and multivessel coronary artery disease during the index hospitalization has garnered considerable interest. The utilization of venoarterial extracorporeal membrane oxygenation (VA-ECMO) in PCI has notably increased, serving both as an emergency intervention in acute myocardial infarction (AMI) and in planned PCI to maintain hemodynamics and organ perfusion. The term "high-risk PCI" has been introduced to denote interventions performed using short-term mechanical circulatory support, necessitating a multidisciplinary approach for patient management. Aim. This study aims to investigate the management approaches for high-risk PCI patients using mechanical circulatory support methods. Materials and Methods. A comprehensive literature review on the management of high-risk PCI patients was conducted. Patients with STEMI who underwent LCA trunk stenting at the bifurcation site using ECMO were selected based on the Barnaul ACCD. Results. Data on ECMO use in high-risk PCI are primarily limited to single-center observational studies or individual clinical cases. In the presented cases, ECMO facilitated successful implementation of complex PCI in patients with STEMI and critical stenoses of large coronary arteries. Indications for routine use of mechanical devices during PCI procedures should be individualized, considering potential benefits and complications. In the cases presented, ECMO use during XRD enabled complete revascularization despite acute heart failure and cardiogenic shock, leading to rapid patient stabilization and discharge in satisfactory condition. Conclusions. Managing high-risk PCI patients necessitates a multidisciplinary approach, requiring collaboration among endovascular surgeons, clinical cardiologists, and cardiac surgeons. Critical aspects in the intensive care unit for these patients are not yet fully understood, emphasizing the need to optimize patient condition pre-procedure, manage concurrent diseases, and ensure adequate postoperative care. The synergy between intensive care specialists and cardiologists can significantly impact treatment outcomes in this clinical context.

Versatile, in-line optical oxygen tension sensors for continuous monitoring during ex vivo kidney perfusion.

Integration of physiological sensing modalities within tissue and organ perfusion systems is becoming a steadily expanding field of research, aimed at achieving technological breakthrough innovations that will expand the sites and clinical settings at which such systems can be used. This is becoming possible in part due to the advancement of user-friendly optical sensors in recent years, which rely both on synthetic, luminescent sensor molecules and inexpensive, low-power electronic components for device engineering. In this article we report a novel approach towards enabling automated, continuous monitoring of oxygenation during ex vivo organ perfusion, by combining versatile flow cell components and low-power, programmable electronic readout devices. The sensing element comprises a 3D printed, miniature flow cell with tubing connectors and an affixed oxygen-sensing thin film material containing in-house developed, brightly-emitting metalloporphyrin phosphor molecules embedded within a polymer matrix. Proof-of-concept validation of this technology is demonstrated through integration within the tubing circuit of a transportable medical device for hypothermic oxygenated machine perfusion of extracted kidneys as a model for organs to be preserved as transplants.

Hemodynamic assessment and management of septic shock in children

Abstract The three main pathophysiologic contributors to septic shock include varying combinations of hypovolemia (relative &gt; absolute), vasoplegia, and myocardial dysfunction. The three pillars of hemodynamic support include fluid boluses (FBs), vasopressors ± inotropic agents. The three goals of hemodynamic resuscitation include an adequate cardiac output (CO)/clinical perfusion markers, pressure parameters (adequate mean arterial pressure [MAP] and diastolic blood pressure [DBP]) for organ perfusion, and avoiding congestion (worse filling) parameters. Fluid bolus-induced CO improvements are variable (33%–50%) and ill-sustained on account of sepsis-mediated glycocalyx injury. A pragmatic approach is to administer a small bolus (10 mL/kg over 20–30 min) as a test and judge the response based on clinical perfusion markers, pressure parameters, and congestive features. Vasoplegia is characterized by low DBP, which is a major contributor to hypotension in septic shock; furthermore, FBs may exacerbate vasoplegia. A strategy of restricted FB with early low-dose norepinephrine (NE) (0.05–0.1 µg/kg/min) can be helpful. NE has press or effects and also mild inotropy and can be a useful first-line vasoactive even in patients with mild-moderate septic myocardial dysfunction (SMD) to maintain adequate coronary perfusion and DBP while minimizing tachycardia. Severe SMD may benefit from additional inotropy (epinephrine/dobutamine). Except vasopressin, most vasoactive drugs may safely be administered via a peripheral route. The lowest MAP (5th centile for age) may be an acceptable target, provided that end-organ perfusion and organ function (mentation and urine output) are satisfactory. An individualized rather than protocolized approach combining the history, physical examination, laboratory analyses, available monitoring tools, and re-assessments can improve outcomes.

Development of a novel artificial normothermic organ perfusion preservation solution and its application in DCD donor liver preservation

Development of a novel artificial normothermic organ perfusion preservation solution and its application in DCD donor liver preservation

Beating Heart Transplants—Overview and Implications for Anesthesiologists

As the demand of heart allografts for transplantation continues to rise, ex-vivo organ perfusion strategies are playing an increasingly important role in preservation of organs from donation after circulatory death (DCD) and extended-criteria donors. One such method utilizes the Organ Care System™ (TransMedics, Andover, MA). Traditionally, this technique of preservation requires two periods of warm ischemia and subsequent cardioplegic arrest. In a novel surgical technique pioneered at our institution, heart allograft implantation no longer requires a second cardioplegic arrest. This article discusses the surgical approach for this procedure, advantages and disadvantages to this approach, and analogues to current clinical practice to theorize what impact this may have on cardiac transplantation volumes in the future.

The heart, a secondary organ in the control of blood circulation.

Circulation of the blood is a fundamental physiological function traditionally ascribed to the pressure-generating function of the heart. However, over the past century the 'cardiocentric' view has been challenged by August Krogh, Ernst Starling, Arthur Guyton and others, based on haemodynamic data obtained from isolated heart preparations and organ perfusion. Their research brought forth experimental evidence and phenomenological observations supporting the concept that cardiac output occurs primarily in response to the metabolic demands of the tissues. The basic tenets of Guyton's venous return model are presented and juxtaposed with their critiques. Developmental biology of the cardiovascular system shows that the blood circulates before the heart has achieved functional integrity and that its movement is intricately connected with the metabolic demands of the tissues. Long discovered, but as yet overlooked, negative interstitial pressure may play a role in assisting the flow returning to the heart. Based on these phenomena, an alternative circulation model has been proposed in which the heart functions like a hydraulic ram and maintains a dynamic equilibrium between the arterial (centrifugal) and venous (centripetal) forces which define the blood's circular movement. In this focused review we introduce some of the salient arguments in support of the proposed circulation model. Finally, we present evidence that exercising muscle blood flow is subject to local metabolic control which upholds optimal perfusion in the face of a substantive rise in muscle vascular conductance, thus lending further support to the permissive role of the heart in the overall control of blood circulation.

Mesenteric Ischemia.

Mesenteric ischemia occurs when perfusion of the visceral organs fails to meet normal metabolic requirements and subsequently results in abdominal symptoms such as diffuse postprandial pain, peritonitis, food fear, and weight loss. While generally divided into acute and chronic manifestations, mesenteric ischemia is commonly misdiagnosed at initial presentation due to the significant overlap with symptoms of other abdominal pathologies. Prompt recognition and diagnosis, mesenteric revascularization, and critical care management remain the mainstay of treatment in these patients for optimal outcomes. This review will highlight acute versus chronic mesenteric ischemia, their etiology, diagnostic criteria, treatment options, and will emphasize the joint role of the gastrointestinal and vascular surgeon in the timely management of this condition to prevent devastating outcomes.

Argipressin-norepinephrine association in the treatment of septic shock: the use of the polydistrectual resistance index as an assessment of vascular compliance

IntroductionThe hemodynamic management of septic patients involves initial fluid therapy, followed by the use of vasoconstrictors in case of treatment failure. The latest Surviving Sepsis Campaign guidelines suggest the synergistic use of argipressin in addition to norepinephrine when hemodynamic optimization is not achieved with norepinephrine alone.MethodsIn our single-center retrospective observational study, the primary endpoint is the safety of initial norepinephrine-argipressin association treatment, assessed through a reduction in Resistance Index. Our secondary endpoint includes the efficacy of this combination, measured by an increase in Mean Arterial Pressure and a reduction in Resistance Index as an indicator of organ perfusion. The Resistance Index (RI) is evaluated through Power Doppler ultrasound. RI is crucial for assessing multi-district vascular tone and multiorgan perfusion. Patients were categorized into three groups based on their treatment. In Group 1, we analyzed patients treated with norepinephrine alone in incremental doses; in Group 2, we analyzed patients receiving the initial norepinephrine-argipressin association treatment (norepinephrine 0.05 mcg/kg/min-argipressin 0.03 IU/min); in the third group (Group 3), we analyzed patients given argipressin (0.03 IU/min) after norepinephrine (&amp;lt;0.10–0.25≥ mcg/kg/min) to stabilize their hemodynamics (MAP &amp;gt; 65 mmHg). RI measurements were taken in the Renal Artery (ARE), Radial Artery (AR), Central Retinal Artery (CRA), and Superior Mesenteric Artery (AMS) at four different time points: T0 before vasopressor therapy, T1 at 1 h, T2 at 24 h, and T3 at 48 h after vasopressor infusion.ResultsA total of 48 patients were divided into three groups: 17 patients in Group 1, 16 in Group 2, and 15 in Group 3. In Group 1, an increase in Mean Arterial Pressure (MAP) was observed, but there was an increase in RIs in the right CRI and left ARE. In Group 2, there was an improvement in MAP and a reduction in RIs in the right/left CRI, left ARE, AMS, and right AR. In Group 3, there was an increase in MAP and a reduction in RIs in the right/left CRI, left ARE, AMS, and right AR.ConclusionEarly norepinephrine-argipressin association treatment appears to be a valid strategy for hemodynamic optimization in this patient population.

Central vs peripheral vascular factors determining risk of aortic dissection

Hypertension is the commonest cause of “central” aortic dissection, despite being an “peripheral” arteriole disease. We hypothesised that known regional variations in peripheral organ perfusion, due to variation in arteriole tone, via its effect on differential head and neck vessel flows can alter the risk and location of central aortic dissection. This might help to explain why some hypertensive patients dissect their aorta and others don't despite having similar aortic geometry. We utilised a simple 2D computational fluid dynamic model to test our hypothesis. We hypothesise (1) that variations in “peripheral” organ flow can alter the site of “central” aortic dissection, despite the blood pressure and cardiac output being identical, (2) variations in cardiac output at rest may also help to explain the risk of dissection but not the site of the initial intimal tear, and (3) atrial fibrillation, a known factor for aortic dissection, increases the risk via stroke volume variation. MRI scanning, via regional aortic branch flow quantification, may help to identify individuals who have a family history of dissection/aneurysm, who are normotensive with normal aortic anatomy that have a high potential risk for dissection due to calculated high wall velocity/shear stresses. This may allow selective beta blocker prescriptions in an asymptomatic patient population that is at a predicted high risk of aortic dissection – a hither to unidentified patient subpopulation.