Decrease In Perfusion Pressure Research Articles

Diagnostics of acute compartment syndrome : Current gold standard and the state of science of noninvasive assessment methods

Acute compartment syndrome (ACS) is defined by a disorder of the microcirculation due to a persistent pathological pressure increase within amuscle compartment. The ischemia of the tissue leads to an initially reversible functional impairment and finally irreversible damage of the musculature, nerves and other structures. Based on the understanding of the pathophysiology, the current diagnostic concepts and treatment using the so-called dermatofasciotomy of the affected muscle compartments can be derived. In addition to the suspicion of a possible ACS based on the medical history of the patient, the findings of the clinical examination are decisive. This review article gives a summary of all the essential aspects of the diagnostics. In clinically uncertain cases and for monitoring, an objectification of the findings using instrument-based techniques is increasingly required. Nowadays, invasive needle pressure measurement is available; however, due to limited reliability, specificity and sensitivity, these measurements only represent an aid to decision guidance supporting or advising against the indications for dermatofasciotomy. The increasing demands on making a certain diagnosis and justification of a surgical intervention from a legal point of view, substantiate the numerous scientific efforts to develop noninvasive instrument-based diagnostics. These methods are based either on detection of increasing intracompartmental pressure or decreasing perfusion pressure and microcirculation. The various measurement principles are summarized in a lucid form.

Biological activity of a benzene sulfonamide on perfusion pressure and coronary resistance using an isolated rat heart model

There are studies which indicate that some sulfonamide derivatives can produce changes in the cardiovascular system; however, their biological activity on perfusion presure and coronary resistance is not clear. The aim of this research was to evaluate the effect exerted by benzenesulfonamide, and their derivatives (2,5-dichloro- N-(4-nitro-phenyl)-benzene-sulfonamide, 2-hydrazino-carbonyl-benzenesulfonamide, 4-(2-amino-ethyl)-benze- ne-sulfonamide, and 4-[3-(4-nitro-phenyl)-ureido]-benzene- sulfonamide) on perfusion pressure and coronary reistance. To evaluate the biological activity of benzenesulfonamide and their derivatives on perfusion pressure and coronary reistance an isolated rat heart model was used. Furthermore, theoretical interaction of 4-(2-amino-ethyl)-benzenesul- fonamide with Calcium channel surface was determined using 6jp5 protein, nifedipine, amlodipine, verapamil and BayK 8644 as theoretical tools in a DockingServer program. The Results showed that 4-(2-amino-ethyl)-ben- zenesulfonamide decreased perfusion pressure and coronary resistance compared to benzenesulfonamide, 2,5-dichloro- N-(4-nitro-phenyl)-benzene-sulfonamide, 2-hydrazinocar- bonyl-benze-nesulfonamide, 4-[3-(4-nitro-phenyl)-ureido]- benenesulfonamide and the control conditions. Besides, theoretical data suggest that 4-(2-aminoethyl)benzenesulfo- namide could interact with aminoacid residues such as Glu614 and Ala320 involved in 6jp5 protein surface. This phenomenon could result in an ligand-Calcium channel complex formation to produce a decrease in perfusion pressure and vascular resistance. It is noteworthy that biological and experimental models used in this study is an invaluable research tool for investigating questions across the spectrum of physiologic functions of cardiovascular system such as perfusion pressure and coronary resistance

Mean Ocular Perfusion Pressure Effect During Pars Plana Vitrectomy on the Foveal Avascular Zone: A Pilot Study.

Purpose: To evaluate the effect of mean ocular perfusion pressure on the foveal avascular zone (FAZ) area in eyes with successful retinal detachment (RD) surgery. Methods: This prospective pilot fellow eye-controlled study measured the intraoperative mean ocular perfusion pressure in eyes having surgery for rhegmatogenous RD (RRD). Postoperatively, the FAZ area was measured; the change was calculated as the difference in the FAZ area between the operated eye and the contralateral control eye. Results: The study comprised 8 patients with a mean age (±SD) of 53.38 ± 13.92 years. The mean superficial FAZ area was not different between operated eyes and control eyes, while the deep FAZ area was significantly larger in operated eyes. There was a strong negative correlation between the mean ocular perfusion pressure and the change in the deep FAZ area (Spearman ρ, -0.73; P = .04); the correlation between the mean ocular perfusion pressure and the change in the superficial FAZ area was not significant (Spearman ρ, -0.24; P = .57). A significant linear regression was found between the mean ocular perfusion pressure and the change in the deep FAZ area (R2 = 0.388). The predicted enlargement of the deep FAZ area was 0.03 mm with every 1 mm Hg decrease in the mean ocular perfusion pressure. Conclusions: Lower intraoperative mean ocular perfusion pressure is associated with enlargement of the deep FAZ area in eyes having successful RRD surgery.

Features of Hemodynamics in Elderly Patients Undergoing CABG Surgery at the Stage of Induction Anesthesia

Due to the global trend of the population ageing, an important task of modern medicine is to improve the provision of medical care for elderly patients. These people have reduced compensatory reserves of the body and numerous chronic pathologies, necessitating a more meticulous approach to anesthesia induction and maintenance by anesthesiologists. According to the authors, the use of propofol and fentanyl leads to decreased myocardial contractility and reduction in overall peripheral vascular resistance. However, the resulting decrease in perfusion pressure in vital organs and tissues, as a consequence of the aforementioned effects, is unacceptable in elderly patients with coronary heart disease (CHD).
 The aim
 . To analyze changes in hemodynamics in elderly patients undergoing coronary artery bypass grafting (CABG) during the induction of anesthesia.
 
 Materials and methods. A prospective study was conducted which included the results of examination of 20 patients with CHD over 60 years old who underwent CABG without the use of cardiopulmonary bypass at the National Amosov Institute of Cardiovascular Surgery (Kyiv, Ukraine). The mean age of the patients was 67.5±6.8 years. There were 16 (80%) men and 4 (20%) women. Typical manifestations of heart failure were noted (there were 1 [5%], 10 [50%] and 9 [45%] NYHA functional class I, II and III patients, respectively). Also, the patients were classified according to the Canadian classification of angina: 1 (5%), 9 (45%) and 10 (50%) patients fell within class I, II and III, respectively. Stage 2-3 hypertension was reported in 18 patients (90%).
 For induction of anesthesia, the following medications were used: propofol 1.5 mg/kg, fentanyl 2.0 μg/kg, and rocuronium bromide 0.1 mg/kg. Anesthesia maintenance included: propofol 4 mg/kg/hour, fentanyl 2.0 μg/kg/hour. Hemodynamic parameters saturation indices (SpO2), and transthoracic echocardiography parameters were recorded at the following stages: 1) upon the patient’s arrival in the operating room; 2) prior to tracheal intubation; 3) immediately after tracheal intubation; 4) 25 minutes after intubation.
 Results. Upon arrival in the operating room, the hemodynamic parameters reflected stable general condition of the examined patients. After administration of induction agents according to the study design, it was recorded that mean blood pressure (BP) was 72.7±4.76% (p<0.001), heart rate was 89.8±5.95% (p=0.0004), cardiac index was 81.47±6.6% (p<0.001), and systemic vascular resistance index (SVRI) was 89.9±7.02% of the baseline values (p=0.063). After intubation, an increase in most hemodynamic indicators was observed, although only mean BP, which constituted 86.7±8.8% of the baseline data (p<0.001), and SVRI (89.8±11.04% of the baseline data, p=0.0315), significantly differed from the baseline values. Within 25 minutes after the intubation, the parameters decreased again: with mean BP 74.9±7.9% (p<0.001), heart rate 91.3±9.5% (p=0.008), cardiac index 79.6±10.1% (p<0.001), and SVRI 91.1±9.34% (p=0.062) of the baseline values.
 Conclusions. The main changes in hemodynamics were reported during induction of anesthesia, where a significant decrease in most indicators compared to the baseline state was recorded. After intubation, the parameters slightly increased but did not return to the baseline values. During further anesthesia maintenance, a significant decrease in most indicators relative to the baseline data were observed. The instability of hemodynamic parameters during the induction stage of anesthesia in elderly patients with CHD can be an obstacle to the normal course of the perioperative period, necessitating the search for methods to stabilize them.

Проблемні питання патогенезу, діагностики, профілактики та підходи до лікування артеріальної гіпотензії в дітей (літературні дані, власні дослідження)

Arterial hypotension (AHT) is an actual problem in pediatrics. It is a symptom complex characterized by a decrease in systemic blood pressure (BP) and accompanied by a number of clinical symptoms that reflect a decrease in blood flow and perfusion pressure in all organs and tissues. Purpose - to summarize data from the literature and own experience regarding diagnosis, pathogenetic and clinical features of the course and principles of treatment of AHT in children. Results. A review of modern literary data showed a wide range of etiopathogenetic mechanisms of AHT formation and a high specific weight of primary AHT in the pediatric population. A modern method of accurate diagnosis of AHT is daily blood pressure monitoring (DBPM). According to the results of DBPM conducted by us in 677 children aged 8-17 years with complaints of BP fluctuations, AHT was established in 107 (15.8%) examined. AHT in girls occurred almost twice as often compared to boys - 66.4% versus 33.6% (p<0.0001). In 64.5% of cases there was labile AHT, in 33% - stable AHT of the first stage, in 2.5% of children - stable AHT of the II stage. There were no gender differences in the frequency of different degrees of AHT. Conclusions. The issue of low BP is an urgent problem in pediatrics. According to the results of DBPM, AHT is detected in 15.8% of children aged 8-17 years and has a mostly labile course. AHT requires in-depth study in order to develop new preventive and therapeutic measures and to alleviate the consequences in children. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of participating institution. The informed consent of the patient was obtained for conducting the studies. No conflict of interest was declared by the authors.

A Decrease in Effective Renal Perfusion Pressure Is Associated With Increased Acute Kidney Injury in Patients Undergoing Cardiac Surgery.

This study aimed to evaluate the relationship between intra-abdominal pressure (IAP), renal perfusion indices, and postoperative acute kidney injury (AKI) in cardiac patients. In a prospective cohort study conducted at a single academic institution, we collected data from adult patients undergoing open-heart operations with cardiopulmonary bypass (CPB) at our institution from February 2022 to April 2022 using the Accuryn SmartFoley system® (Potrero Medical, Hayward, CA). Patients on mechanical support devices, pregnant patients, and patients on hemodialysis were excluded. Demographics, hemodynamics, and mean airway pressure (mAir) were measured at the beginning of the cardiac operations and during the first four hours of ICU. Renal perfusion indices were then calculated (mean perfusion pressure (MPP) = mean arterial pressure (MAP) - central venous pressure (CVP); abdominal perfusion pressure (APP) = MAP - IAP; and effective renal perfusion pressure (eRPP) = MAP - (CVP + mAir + IAP)). Length of stay (LOS) was measured from the day of surgery to ICU discharge (ICU LOS) and hospital discharge (hospital LOS). During the first four hours of ICU stay, the non-AKI group had lower IAP and higher renal perfusion indices (MPP, APP, and eRPP). Logistic regression showed high perfusion pressures correlated with lower postoperative AKI (all OR <1, p<0.05). The postoperative AKI group also had significantly longer ICU LOS (7.33 vs. 4.57 days) and hospital LOS (17.0 vs. 10.2 days). Renal perfusion indices are a promising tool to predict postoperative AKI in cardiac surgery patients.

Evaluation of biological activity of some pyridine derivatives on perfusion pressure and their interaction with the M2 muscarinic receptor

AbstractThe aim of this study was to evaluate the biological activity of some pyridine derivatives (compounds 1 to 15) on perfusion pressure in an isolated rat heart model. Furthermore, theoretical interaction of pyridine derivatives with the M2 muscarinic receptor was determined using acetylcholine, AF‐DX 116 and the 3uon protein as theoretical tools in a docking model. Results showed that pyridine derivatives 6, 9, and 13 decreased perfusion pressure compared to control conditions and compounds 1‐5, 7, 8, 10‐12, 14, and 15. Furthermore, theoretical data indicates that different amino acid residues are involved in the interaction of pyridine derivatives with the protein surface. Other data indicate that the inhibition constant was lower for compounds 6, 9 and 13 compared to acetylcholine and AF‐DX 116. In conclusion, all these data suggest that pyridine derivatives 6, 9 and 13 can produce changes in perfusion pressure possibly through activation of the M2 muscarinic receptor, and this phenomenon could depend on the different functional groups involved in its chemical structure.

Defining Hemodynamic Significance of Renal Artery Stenosis: Insights From a Porcine Model of Graded Renal Artery Stenosis

To investigate the renal pressure-flow relationship and its relation to renin release, because the renal perfusion pressure below which renal flow starts to decline and renin secretion isupregulatedis unclear. A porcine model of graded unilateral renal artery stenosis was created. The severity of the stenosis was expressed as the ratio between distal renal pressure (Pd) and aortic pressure (Pa). Pd and renal flow velocity were continuously measured using a combined pressure-flow wire (Combowire®). Hemodynamic measurements and blood sampling for renin, angiotensin and aldosterone were performed in baseline conditions and during progressive balloon inflation in the renal artery leading to Pd decrease per 5% increment. Resistive index (RI)was computed as (1-(End Diastolic V/Peak Systolic V))*100. For a 5% decrease in renal perfusion pressure (95% of aortic pressure or 5% decrease compared to Pa), peak systolic velocity started to decrease. A significant decrease in average peak flow velocitywas observed when distal renal perfusion pressure decreased by 25% and was associated with activation of ipsilateral renin secretion. The RI decreased already for minimal changes in Pd/Pa ratio. In an animal model of unilateral graded renal artery stenosis, a 25% decrease in perfusion pressure results in a significant decrease in distal renal flow, causing upregulation of renin secretion.

Comprehensive Management of Blood Pressure in Patients with Septic AKI.

Acute kidney injury (AKI) is one of the serious complications of sepsis in clinical practice, and is an important cause of prolonged hospitalization, death, increased medical costs, and a huge medical burden to society. The pathogenesis of AKI associated with sepsis is relatively complex and includes hemodynamic abnormalities due to inflammatory response, oxidative stress, and shock, which subsequently cause a decrease in renal perfusion pressure and eventually lead to ischemia and hypoxia in renal tissue. Active clinical correction of hypotension can effectively improve renal microcirculatory disorders and promote the recovery of renal function. Furthermore, it has been found that in patients with a previous history of hypertension, small changes in blood pressure may be even more deleterious for kidney function. Therefore, the management of blood pressure in patients with sepsis-related AKI will directly affect the short-term and long-term renal function prognosis. This review summarizes the pathophysiological mechanisms of microcirculatory disorders affecting renal function, fluid management, vasopressor, the clinical blood pressure target, and kidney replacement therapy to provide a reference for the clinical management of sepsis-related AKI, thereby promoting the recovery of renal function for the purpose of improving patient prognosis.

Paracentral acute middle maculopathy secondary to retinal artery macroaneurysm elucidates anatomy and physiology of retinal capillary plexus

AbstractPurpose: To report a novel case of Paracentral Acute Middle Maculopathy (PAMM) Secondary to Retinal Artery Macroaneurysm.Methods: A case report.Results: A 72‐year‐old lady presented with three‐month history of sudden onset left paracentral scotoma. Her medical history include hypertension and hyperlipidemia. Visual acuity was 6/7.5 and 6/45 in the right and left eye respectively. Anterior segment examination and intraocular pressures were unremarkable. A ruptured retinal arterial macroaneurysm (RAM) was seen along the second‐order artery along the inferotemporal arcade with a small area of deep‐retinal whitening along the distal branches of the artery. Corresponding optical coherence tomography showed a round superficial retinal hyperreflective lesion consistent with RAM and hyperreflective band involving the outer plexiform layer (OPL), inner nuclear layer (INL) and inner plexiform layer (IPL) consistent with PAMM. Confocal scanning laser ophthalmoscopy video fluorescein angiogram (FA) demonstrated a ruptured and hemorrhagic RAM with significantly delayed distal filling of the artery, with resultant PAMM in an area supplied by the tributary arterioles of the affected artery.Conclusions: Oxygen consumption is highest at the metabolically active middle retinal layer. The inner and middle retinal layers are supplied by the superficial capillary plexus in the ganglion cell layer, intermediate capillary plexus (ICP) in the INL‐IPL boundary and deep capillary plexus (DCP) in the INL‐OPL boundary. Rupture and partial thrombosis of the RAM resulted in mechanical narrowing of the vessel lumen and severe flow limitation, which was further exacerbated by her history of hypertension and hyperlipidemia. This was consistent with the FA findings of delayed filling in the distal parts of the artery. Flow limitation results in decreased blood supply to the retinal capillary plexuses, further decreasing perfusion pressure, causing most disruption to the delicately balanced ICP and DCP blood supply of the middle retinal layer. Middle retinal infarction occurs most readily and presents as PAMM in our patient. In conclusion, we described a novel case of PAMM secondary to a ruptured and partially thrombosed RAM which clearly elucidates the anatomy and physiology of retinal capillary plexuses.

A study of changes in Mean Ocular Perfusion Pressure and Intra-Ocular Pressure among patients undergoing hemodialysis

Abstract Background:During hemodialysis there is decrease in both systolic blood pressure (SBP) and diastolic blood pressure (DBP) and hence Mean Arterial Pressure (MAP) due to decrease in body fluid volume. Due to reduction in MAP there is decrease in Mean Ocular Perfusion Pressure (MOPP) and also there is increase in IOP during dialysis. Objective:To study changes in MOPP and IOP among patients undergoing hemodialysis Methods:An observational study was carried out among 100 patients undergoing hemodialysis Under aseptic condition, Proparacaine eye drops were instilled in both eyes, IOP was measured by Schiotz Indentation Tonometer 30 min before, during hemodialysis and 30 min after hemodialysis in supine position. Tonometer was sterilized by Isopropyl alcohol and was washed with normal saline before using on next patient. Systolic and diastolic blood pressure were measured by using sphygmomanometer 30 min before, during and 30 min after hemodialysis. Results:The variations in the SBP, DBP and MAP before, during and after hemodialysis were not statistically significant (p&gt;0.05). There was significant differences for IOP between before, during and after hemodialysis and same for MOPP except before and 30 min after hemodialysis (p &lt; 0.0001). Conclusion:Significant fluctuations were seen from the present study in the intra-ocular pressure and mean ocular perfusion pressure during, before and after hemodialysis.

Regional hemodynamics characteristics in patients with non-arteritic anterior ischemic optic neuropathy

BACKGROUND: Non-arteritic anterior ischemic optic neuropathy (NAION) takes the first place in the total amount of acute vascular optic neuropathy cases. There is no common understanding of pathogenetic mechanisms of disease. This is largely due to the absence of direct optic nerve head blood flow registration method in ophthalmology.&#x0D; AIM: The aim of this work is to evaluate ocular hemodynamics using different methods in patients with non-arteritic anterior ischemic optic neuropathy (NAION).&#x0D; MATERIALS AND METHODS: 73 patients were enrolled in the study. 46 patients (46 eyes) with NAION were included in the first group. Control group was composed of 27 patients (50 eyes) with systemic risk factors of NAION without any retinal and optic nerve diseases. Regional hemodynamics parameters were evaluated with ophthalmosphigmography, ophthalmoplethysmography, ophthalmoreography, OCT-angiography and EDI-OCT.&#x0D; RESULTS: Blood flow values in different parts of the choroid did not statistically differ between groups when using ophthalmosphigmography, ophthalmoplethysmography, ophthalmoreography methods. Radial peripapillary capillaries in optic nerve head area were evaluated, and statistically significant difference was found in all sectors.&#x0D; CONCLUSION: The main component of NAION pathogenesis is a decreasing perfusion pressure in paraoptic short posterior ciliary arteries. Blood flow in choroid does not play an important role in the disease pathogenesis.

OVLT Lesion attenuates hypertension and polydipsia in 2‐kidney, 1‐clip hypertensive Rats

Hypertension (HTN) is a multifaceted condition that affects one‐third of the population of western countries. It is well established that renal ischemia results in secondary renovascular HTN. Experimental renovascular HTN is induced in rats by creating stenosis of the left renal artery, thereby decreasing perfusion pressure (2K1C‐HTN), leading to increased renin‐angiotensin system activity which may act centrally to increase arterial pressure, sympathetic nerve activity, and thirst. The organum vasculosum of the lamina terminalis (OVLT) is a circumventricular organ which is responsive to blood borne substances such as angiotensin II and has been implicated in the regulation of arterial pressure, sympathetic activity, and thirst. Previous studies have shown that OVLT lesion attenuates development of the DOCA‐model of hypertension, but does not modify the water intake (Collister et al., 2018). In the present study we tested the hypothesis that the OVLT is required for the development of 2K1C‐HTN as polydipsia is observed in this model. Male Sprague‐Dawley rats (n=3‐5/group) were randomly selected to receive either electrolytic lesion of the OVLT (OVLTx) or sham operation. After one week, they were instrumented with telemeters to measure mean arterial pressure (MAP). Two weeks after OVLTx, the left renal artery was stenosed by application of a silver clip. MAP was measured continuously for 6 weeks and, once a week, rats were housed in metabolic cages for 24 hours to measure water intake and urine volume. At the end of the protocol, MAP was significantly (p&lt;0.001) lower in OVLTx‐2K1C (134±8 mmHg) compared to sham lesion‐2K1C (163±6 mmHg) rats. In addition, water intake was significantly (p&lt;0.001) lower in OVLTx‐2K1C (42±2 ml/day) compared to sham lesion‐2K1C (73±2 ml/day) rats. Similarly, urinary volume excretion was reduced in OVLTx‐2K1C (25±2 ml/day) compared to sham lesion‐2K1C (52±5 ml/day) rats. We conclude that the integrity of OVLT is required for the development of 2K1C hypertension as well the polydipsia observed following renal artery stenosis.

Optimal Cerebral Perfusion Pressure During Delayed Cerebral Ischemia After Aneurysmal Subarachnoid Hemorrhage.

The recommendation of induced hypertension for delayed cerebral ischemia treatment after aneurysmal subarachnoid hemorrhage has been challenged recently and ideal pressure targets are missing. A new concept advocates an individual cerebral perfusion pressure where cerebral autoregulation functions best to ensure optimal global perfusion. We characterized optimal cerebral perfusion pressure at time of delayed cerebral ischemia and tested the conformity of induced hypertension with this target value. Retrospective analysis of prospectively collected data. University hospital neurocritical care unit. Thirty-nine aneurysmal subarachnoid hemorrhage patients with invasive neuromonitoring (20 with delayed cerebral ischemia, 19 without delayed cerebral ischemia). Induced hypertension greater than 180 mm Hg systolic blood pressure. Changepoint analysis was used to calculate significant changes in cerebral perfusion pressure, optimal cerebral perfusion pressure, and the difference of cerebral perfusion pressure and optimal cerebral perfusion pressure 48 hours before delayed cerebral ischemia diagnosis. Optimal cerebral perfusion pressure increased 30 hours before the onset of delayed cerebral ischemia from 82.8 ± 12.5 to 86.3 ± 11.4 mm Hg (p < 0.05). Three hours before delayed cerebral ischemia, a changepoint was also found in the difference of cerebral perfusion pressure and optimal cerebral perfusion pressure (decrease from -0.2 ± 11.2 to -7.7 ± 7.6 mm Hg; p < 0.05) with a corresponding increase in pressure reactivity index (0.09 ± 0.33 to 0.19 ± 0.37; p < 0.05). Cerebral perfusion pressure at time of delayed cerebral ischemia was lower than in patients without delayed cerebral ischemia in a comparable time frame (cerebral perfusion pressure delayed cerebral ischemia 81.4 ± 8.3 mm Hg, no delayed cerebral ischemia 90.4 ± 10.5 mm Hg; p < 0.05). Inducing hypertension resulted in a cerebral perfusion pressure above optimal cerebral perfusion pressure (+12.4 ± 8.3 mm Hg; p < 0.0001). Treatment response (improvement of delayed cerebral ischemia: induced hypertension+ [n = 15] or progression of delayed cerebral ischemia: induced hypertension- [n = 5]) did not correlate to either absolute values of cerebral perfusion pressure or optimal cerebral perfusion pressure, nor the resulting difference (cerebral perfusion pressure [p = 0.69]; optimal cerebral perfusion pressure [p = 0.97]; and the difference of cerebral perfusion pressure and optimal cerebral perfusion pressure [p = 0.51]). At the time of delayed cerebral ischemia occurrence, there is a significant discrepancy between cerebral perfusion pressure and optimal cerebral perfusion pressure with worsening of autoregulation, implying inadequate but identifiable individual perfusion. Standardized induction of hypertension resulted in cerebral perfusion pressures that exceeded individual optimal cerebral perfusion pressure in delayed cerebral ischemia patients. The potential benefit of individual blood pressure management guided by autoregulation-based optimal cerebral perfusion pressure should be explored in future intervention studies.

The association of cerebrospinal fluid pressure with optic nerve head and macular vessel density.

The present study aims to investigate the effect of temporary cerebrospinal fluid pressure (CSFP) reduction on optic nerve head (ONH) and macular vessel density (VD) using optical coherence tomography angiography. Forty-four eyes of 44 adults with diagnostic lumbar puncture and CSFP reduction were recruited. Thirty-two eyes of 32 healthy volunteers were controls. ONH and macular VD images were evaluated differences between baseline and after CSFP reduction. The results showed that the mean CSFP decreased from (11.6±2.1) mmHg to (8.2±3.4) mmHg (P<0.001). VD in the macular regions decreased significantly after CSFP reduction in the study group (all P<0.05). The control group showed no significant changes in macular VD (all P>0.05). In the study group, decreased VD in the macular parainferior region was associated with CSFP reduction (R2=0.192, P=0.003), the reduction of macular VD in parafoveal (R2=0.098, P=0.018), parainferior (R2=0.104, P=0.021), parasuperior (R2=0.059, P=0.058), paranasal (R2=0.057, P=0.042), paratemporal (R2=0.079, P=0.026) was associated with mean ocular perfusion pressure decrease following CSFP reduction. ONH vessel density did not differ after CSFP reduction (all P>0.05). In conclusion, macular vessel density decreased in association with CSFP reduction. Retinal vessel density in the macular region is more sensitive than that in peripapillary region after CSFP reduction.

COVID-19 as a new risk factor for the development of acute vascular diseases of the optic nerve and retina

The new coronavirus disease (COVID-19) is a viral respiratory infection accompanied by systemic endotheliitis. COVID-19 patients usually encounter changes related to hypercoagulability, hypofibrinolysis, and increased intravascular platelet aggregation. There is also a vascular wall thromboresistance decrease and impaired vasomotor function, which significantly increase the risk of thromboembolic complications. Currently, pathogenic aspects of the relationship between COVID-19 and vascular and inflammatory conditions of the optic nerve and retina are actively investigated. One of the triggers of impaired blood flow in ocular vessels may be a perfusion pressure decrease, observed in the acute period of the infectious process. This is related to both COVID-19 clinical course features and to resuscitation specificity as well. Secondary autoimmune inflammation is being considered as a mechanism of damage to the vascular wall in the post-infectious period. In this publication, possible pathogenic links of these diseases are considered for the first time in a specific context of the example of ischemic optic neuropathy associated with coronavirus infection.

Immunotherapy for Recurrent orthostatic cerebral hypo-perfusion syndrome in recurrent COVID-19 infection

Orthostatic hypotension, often interpreted as a drop in blood pressure as a person moves from lying or sitting to standing, has a direct impact on the brain. It results in a decrease in brain perfusion pressure and in many cases causes symptoms of transient cerebral hypo perfusion. This report treats a case of recurrent orthostatic hypotension in a field of recurrent Covid-19 infection, with a good clinical response to early immunotherapy. Signs of lung infection retroceded until complete disappearance under treatment with chloroquine sulfate and azythromycin. However, due to persistent signs of dysautonomy and paresthesias, we had subjected the patient to intravenous immunoglobulin immunotherapy with a good therapeutic response until the patient's complete recovery 150 days after the start of treatment. The prognosis remains unknown at this time, as we do not yet have data from large-scale studies on this subject.

Expediency of abdominal drainage after operative delivery in severe preeclampsia

One of the leading mechanisms for the development of severe preeclampsia in pregnant women is a decrease in perfusion pressure in the life-supporting organs, followed by the development of multiple organ failure. In recent years, there have been studies indicating the influence of intraperitoneal hypertension on the perfusion pressure of the pelvic and abdominal organs with the subsequent development of obstetric complications [ 4,2] according to the classification of JAN(2006), pregnancy is included in the list of conditions accompanied by an increase in intraperitoneal pressure. Thus, the prevention and treatment of increased intra-abdominal pressure in pathology accompanied by multiple organ dysfunction and insufficiency, which is observed in preeclampsia, is one of the important problems of modern medicine. The purpose of our study was to determine the feasibility of abdominal drainage during operative delivery for severe preeclampsia.

Beneficial Role of Vitexin and Isovitexin Flavonoids in the Vascular Endothelium and Cardiovascular System

Abstract: Various medicinal plants contain phenolic compounds, which are useful in the treatment of many disease conditions. Particularly, vitexin and its isomer, isovitexin, possess many pharmacological effects including antioxidant, anti-inflammatory, anticancer, antidiabetic, neuroprotective, and antinociceptive activities. Current research has provided evidence for the prospective use of vitexin and isovitexin in the formulation of medicinal products useful in the prevention and treatment of specific ailments. The aim of this review was therefore to examine the influence of vitexin and isovitexin on the vascular system as well as the possible mechanisms through which the flavonoids exert their effects. The review also discussed the importance of vitexin and isovitexin in cardiovascular health through the vascular endothelium. In vivo and in vitro studies suggest that vitexin and isovitexin play a cardioprotective role during ischaemic reperfusion injury and angiogenesis, while isovitexin decreases perfusion pressure and increases the bioavailability of nitric oxide. Taken together, vitexin and isovitexin are promising as therapeutic agents for the formulation of nutraceuticals for the prevention, management and treatment of cardiovascular diseases.

Залежність адаптаційної здатності мітохондрій печінки від способу виділення клітин

When conducting studies on isolated hepatocytes, it is important to obtain cells that retain the functional properties that are characteristic of the whole organ. Increased blood viscosity during liver perfusion, decreased perfusion pressure in blood vessels, and hence hypoxia, are among the factors that may affect the functional state of isolated hepatocytes. The functional state of cells can be estimated by the adaptive capacity of mitochondria, by inducing maximal respiration rate by uncoupling respiration and oxidative phosphorylation due to the addition of FCCP. The research aimed to investigate the adaptive capacity of mitochondria of isolated hepatocytes using in situ and in vitro liver perfusion. Hepatocytes were isolated by the two-staged Seglen method by in situ and in vitro liver perfusion. Isolated hepatocytes, after 15-minute incubation in the medium without addition or with respective oxidative substrate – glutamine, pyruvate, succinate, monomethyl succinate, α-ketoglutarate, dimethyl-α-ketoglutarate (at a concentration of 2 mM) or glucose (10 mM) – were added into the respiratory chamber and FCCP was added in increasing concentrations. It was established that at in situ liver perfusion maximal rate of uncoupled respiration and the optimal concentration of FCCP was higher than at in vitro liver perfusion. Addition of exogenous substrates to a medium increased the respiration rate of hepatocytes. Upon in situ liver perfusion maximal uncoupled respiration rate increased at all causes except glucose, and at in vitro liver perfusion – only when dimethyl-α-ketoglutarate, succinate and monomethyl succinate were used. The optimal concentration of FCCP at in vitro liver perfusion increased due to the addition of glutamine, pyruvate and monomethyl succinate to the medium, and at in situ liver perfusion – only upon glucose oxidation. In both perfusion methods, the highest maximal rate of uncoupled respiration is with the use of monomethyl succinate and the optimal FCCP concentration – upon pyruvate oxidation. Therefore, in situ liver perfusion is better method to obtain stable and metabolically active hepatocytes in support respiratory processes at a high level then in vitro perfusion.