Išeminių audinių perfuzijos pokyčiai atkuriant kraujotaką tiesiogiai pagal angiosomą ir netiesiogiai

Background. Blood flow restore in critical limb ischemia according to angiosomes is becoming very popular. This method allows to restore blood flow precisely to the artery supplying the ischemic zone, based on the angiosome concept. However, angiosome revascularization is not a gold standard because of the lack of evidence supporting this approach. The aim of this study was to compare tissue oxygenation changes in ischemic zone during endovascular revascularization procedure either following angiosome concept or performing indirect revascularization. Methods. A prospective observational study was performed. Patients with critical limb ischemia and tissue loss due to chronic total occlusion of below the knee arteries were included. Endovascular revascularization was performed in all cases. Tissue oxygen saturation was observed intraoperatively using near-infrared spectroscopy. Tissue oxygenation changes near the ischemic wound were compared between direct and indirect revascularization groups. Results. This clinical trial included 30 patients with critical limb ischemia (Rutherford 5) and occluded below the knee arteries intended to treat. In 15 patients the procedure was performed according to angiosome, while the other half underwent indirect revascularization. Tissue oxygenation near the wound was monitored during the intervention. Greater oxygen saturation increase was observed in the group with direct revascularization (29% and 23% accordingly), however the difference between groups was not statistically significant (t-test for independent group, p = 0,544). Conclusions. The increase in tissue oxygen saturation differed very slightly in direct and indirect revascularization groups and the difference was statistically insignificant. Įvadas. Vis populiarėja galūnės kraujotakos atkūrimas pagal angiosomas, esant kritinei galūnės išemijai, t. y. revaskuliarizuojama būtent ta kraujagyslė, kuri maitina pažeistą plotą. Tačiau revaskuliarizacija atsižvelgiant į angiosomas nėra laikoma kritinės galūnių išemijos gydymo standartu, nes mokslinėje literatūroje trūksta įrodymų, pagrindžiančių šio gydymo metodo pranašumus. Pristatomo tyrimo tikslas – palyginti audinių oksigenacijos pokyčius išeminėje zonoje, endovaskuliniu būdu atkūrus kraujotaką tiesiogiai pagal angiosomą ir netiesiogiai. Metodai. Tai perspektyvusis stebimasis tyrimas. Į tyrimą įtraukti pacientai, kuriems diagnozuota kritinė galūnės išemija, esant gangrenai dėl užakusių blauzdos arterijų. Pacientams taikyta endovaskulinė revaskuliarizacija. Procedūros metu oksigenacijos pokyčiai stebėti naudojant artimųjų infraraudonųjų spindulių spektroskopiją. Gauti rezultatai lyginti pacientų, kuriems taikyta tiesioginė ir netiesioginė revaskuliarizacija, grupėse. Rezultatai. Tiriamąją imtį sudarė 30 pacientų, sergančių kritine galūnių išemija (5 Rutherfordo kategorija). Visiems pacientams nustatyta blauzdos arterijų okliuzija, kai reikia atkurti kraujotaką. Tyrimo metu 15 pacientų (50 %) kraujotaka buvo atkurta pagal angiosomą, tokiai pat daliai pacientų (50 %) – ne pagal angiosomą. Visiems tiriamiesiems procedūros metu matuoti oksigenacijos pokyčiai išeminėje zonoje. Didesnis oksigenacijos pokytis pastebėtas pacientų, kuriems atlikta revaskuliarizacija pagal angiosomą, grupėje (atitinkamai 29 proc. ir 23 proc.), bet statistiškai reikšmingo oksigenacijos skirtumo tarp grupių nenustatyta (nepriklausomos grupės t testas, p = 0,544). Išvados. Klinikinio tyrimo metu audinių oksigenacijos pokytis atkuriant kraujotaką pagal angiosomą mažai skyrėsi nuo audinių oksigenacijos pokyčio atkuriant kraujotaką ne pagal angiosomą. Skirtumas nebuvo statistiškai reikšmingas

Location of the internal carotid artery and ophthalmic artery segments for non-invasive intracranial pressure measurement by multi-depth TCD

The aim of the present study was to locate the ophthalmic artery by using the edge of the internal carotid artery (ICA) as the reference depth to perform a reliable non-invasive intracranial pressure measurement via a multi-depth transcranial Doppler device and to then determine the positions and angles of an ultrasonic transducer (UT) on the closed eyelid in the case of located segments. High tension glaucoma (HTG) patients and healthy volunteers (HVs) undergoing non-invasive intracranial pressure measurement were selected for this prospective study. The depth of the edge of the ICA was identified, followed by a selection of the depths of the IOA and EOA segments. The positions and angles of the UT on the closed eyelid were measured. The mean depth of the identified ICA edge for HTG patients was 64.3 mm and was 63.0 mm for HVs (p = 0.21). The mean depth of the selected IOA segment for HTG patients was 59.2 mm and 59.3 mm for HVs (p = 0.91). The mean depth of the selected EOA segment for HTG patients was 48.5 mm and 49.8 mm for HVs (p = 0.14). The difference in the located depths of the segments between groups was not statistically significant. The results showed a significant difference in the measured UT angles in the case of the identified edge of the ICA and selected ophthalmic artery segments (p = 0.0002). We demonstrated that locating the IOA and EOA segments can be achieved using the edge of the ICA as a reference point

Oxygen Saturation Increase in Ischemic Wound Tissues after Direct and Indirect Revascularization

Background: The primary approach for treating ischemic wounds is restoring oxygen supply to the ischemic region. While direct angiosomal revascularization is often associated with better post-operative wound healing and limb salvage, its superiority over non-angiosomal revascularization remains controversial. This study aimed to compare intraoperative tissue oxygen saturation changes in ischemic zones following either direct or indirect revascularization in below-the-knee arteries. Methods: This prospective observational study included patients undergoing direct and indirect below-the-knee endovascular revascularizations. Assignment to the groups was not randomized. Near-infrared spectroscopy was used to monitor rSO2 changes near the ischemic wounds intraoperatively. The changes were compared between the groups. Results: 15 patients (50%) underwent direct angiosomal revascularization, while an equal number of patients underwent indirect revascularization. Overall, a statistically significant increase in regional oxygen saturation was observed after revascularization (p = 0.001). No statistically significant difference was found between the direct and indirect revascularization groups (p = 0.619). Conclusions: This study revealed a minor difference in the oxygen saturation increase between the angiosomal and non-angiosomal revascularization groups. Such a finding indicates that the clinical significance of angiosomal revascularization is negligible and might be concealed by confounding factors, such as the vessel diameter and outflow impact on the restenosis rate

Intraorbital pressure-volume characteristics in a piglet model: In vivo pilot study.

Intracranial pressure measurement is frequently used for diagnosis in neurocritical care but cannot always accurately predict neurological deterioration. Intracranial compliance plays a significant role in maintaining cerebral blood flow, cerebral perfusion pressure, and intracranial pressure. This study's objective was to investigate the feasibility of transferring external pressure into the eye orbit in a large-animal model while maintaining a clinically acceptable pressure gradient between intraorbital and external pressures. The experimental system comprised a specifically designed pressure applicator that can be placed and tightly fastened onto the eye. A pressure chamber made from thin, elastic, non-allergenic film was attached to the lower part of the applicator and placed in contact with the eyelid and surrounding tissues of piglets' eyeballs. External pressure was increased from 0 to 20 mmHg with steps of 1 mmHg, from 20 to 30 mmHg with steps of 2 mmHg, and from 30 to 50 mmHg with steps of 5 mmHg. An invasive pressure sensor was used to measure intraorbital pressure directly. An equation was derived from measured intraorbital and external pressures (intraorbital pressure = 0.82 × external pressure + 3.12) and demonstrated that external pressure can be linearly transferred to orbit tissues with a bias (systematic error) of 3.12 mmHg. This is close to the initial intraorbital pressure within the range of pressures tested. We determined the relationship between intraorbital compliance and externally applied pressure. Our findings indicate that intraorbital compliance can be controlled across a wide range of 1.55 to 0.15 ml/mmHg. We observed that external pressure transfer into the orbit can be achieved while maintaining a clinically acceptable pressure gradient between intraorbital and external pressures

Synthesis and characterization of Cr-doped Pb2Fe2O5 thin films by reactive magnetron sputtering /

Multiferroic materials, which exhibit simultaneous ferroelectricity, ferromagnetism, and ferro-elasticity, have attracted significant attention due to their multifunctional properties. Coupling between ferroelectric and magnetic properties has led to the development of non-volatile memory devices, transducers, magnetic field sensors, and other applications. Pb2Fe2O5 (PFO) is a promising multiferroic material due to it simultaneously exhibiting ferroelectricity and ferromagnetism at room temperature. Doping with aliovalent ions, such as Cr3+, has been proposed as an effective method for enhancing the ferroelectric and magnetic properties, consequently leading to the enhancement of multiferroic properties. The investigation shows that the lead ferrite phase (220) was present in all samples, but its abundance reduced with increasing synthesis temperature due to lead desorption. Dielectric measurements revealed that PFO films with highest Cr concentration had the highest polarization (Pr) of 72.2 μC cm−2. The study also found that the magnetization of PFO films was up to 9.5·10−7 μAm2 at an ambient temperature of 5 K, and the magnetic ordering temperature was 363 K, corresponding to the magnetic ordering temperature of chromium oxides. The morphology of Cr doped PFO films changed with increasing chromium content, resulting in a reduction in grain size and an increase in the film density