Occlusion Test Research Articles

Microvascular effects of oxygen and carbon dioxide measured by vascular occlusion test in healthy volunteers.

Changes in near-infrared spectroscopy-derived regional tissue oxygen saturation (StO2) during a vascular occlusion test (VOT; ischemic provocation of microcirculation by rapid inflation and deflation of a tourniquet) allow estimating peripheral tissue O2 consumption (desaturation slope; DS), vascular reactivity (recovery slope; RS) and post-ischemic hyperperfusion (AUC-H). The effects of isolated alterations in the inspiratory fraction of O2 (FiO2) and changes in expiratory CO2 remain to be elucidated. Therefore, in this secondary analysis we determined the effects of standardized isolated instances of hypoxia, hyperoxia, hypocapnia and hypercapnia on the VOT-induced StO2 changes in healthy volunteers (n=20) to establish reference values for future physiological studies. StO2 was measured on the thenar muscle. Multiple VOTs were performed in a standardized manner: i.e. at room air (baseline), during hyperoxia (FiO2 1.0), mild hypoxia (FiO2≈0.11), and after a second baseline, during hypocapnia (end-tidal CO2 (etCO2) 2.5-3.0vol%) and hypercapnia (etCO2 7.0-7.5vol%) at room air. Differences in DS, RS, and AUC-H were tested using repeated-measures ANOVA. DS and RS remained constant during all applied conditions. AUC-H after hypoxia was smaller compared to hyperoxia (963%*sec vs hyperoxia 1702%*sec, P=0.005), while there was no difference in AUC-H duration between hypoxia and baseline. The StO2 peak (after tourniquet deflation) during hypoxia was lower compared to baseline and hyperoxia (92% vs 94% and 98%, P<0.001). We conclude that in healthy volunteers at rest, common situations observed during anesthesia and intensive care such as exposure to hypoxia, hyperoxia, hypocapnia, or hypercapnia, did not affect peripheral tissue O2 consumption and vascular reactivity as assessed by VOT-induced changes in StO2. These observations may serve as reference values for future physiological studies. This study represents a secondary analysis of an original study which has been registered at ClinicalTrials.gov nr: NCT02561052.

Diagnosis of Skin Vascular Complications Revealed by Time-Frequency Analysis and Laser Doppler Spectrum Decomposition.

Nowadays, photonics-based techniques are used extensively in various applications, including functional clinical diagnosis, progress monitoring in treatment, and provision of metrological control. In fact, in the frame of practical implementation of optical methods, such as laser Doppler flowmetry (LDF), the qualitative interpretation and quantitative assessment of the detected signal remains vital and urgently required. In the conventional LDF approach, the key measured parameters, index of microcirculation and perfusion rate, are proportional to an averaged concentration of red blood cells (RBC) and their average velocity within a diagnostic volume. These quantities compose mixed signals from different vascular beds with a range of blood flow velocities and are typically expressed in relative units. In the current paper we introduce a new signal processing approach for the decomposition of LDF power spectra in terms of ranging blood flow distribution by frequency series. The developed approach was validated in standard occlusion tests conducted on healthy volunteers, and applied to investigate the influence of local pressure rendered by a probe on the surface of the skin. Finally, in limited clinical trials, we demonstrate that the approach can significantly improve the diagnostic accuracy of detection of microvascular changes in the skin of the feet in patients with Diabetes Mellitus type 2, as well as age-specific changes. The results obtained show that the developed approach of LDF signal decomposition provides essential new information about blood flow and blood microcirculation and has great potential in the diagnosis of vascular complications associated with various diseases.

End-expiratory Occlusion Test and Mini-fluid Challenge Test for Predicting Fluid Responsiveness in Acute Circulatory Failure.

Predicting which patients with acute circulatory failure will respond to the fluid by an increase in cardiac output is a daily challenge. End-expiratory occlusion test (EEOT) and mini-fluid challenge (MFC) can be used for assessing fluid responsiveness in patients with spontaneous breathing activity, cardiac arrhythmias, low-tidal volume and/or low lung compliance. The objective of the study is to evaluate the value of EEOT and MFC-induced rise in left ventricular outflow tract (LVOT) velocity time integral (VTI) in predicting fluid responsiveness in acute circulatory failure in comparison to the passive leg-raising (PLR) test. Hundred critically ill ventilated and sedated patients with acute circulatory failure were studied. LVOT VTI was measured by transthoracic echocardiography before and after EEOT (interrupting the ventilator at end-expiration over 15 s), and before and after MFC (100 ml of Ringer lactate was infused over 1 min). The variation of LVOT VTI after EEOT and the MFC was calculated from the baseline. Sensitivity, specificity, and area under the receiver-operating characteristic (AUROC) curve of LVOT VTI after EEOT and MFC to predict fluid responsiveness were determined. After PLR, stroke volume (SV) increased by ≥12% in 49 patients, who were defined as responders and 34 patients in whom the increase in SV <12% were defined as nonresponders. A cutoff of 9.1% Change in VTI after MFC (ΔVTIMFC) predicted fluid responsiveness with an AUROC of 0.96 (P < 0.001) with sensitivity and specificity of 91.5% and 88.9%, respectively. Change in VTI after EEOT (ΔVTIEEOT) >4.3% predicted fluid responsiveness with sensitivity and specificity 89.4% and 88.9%, respectively, with an AUROC of 0.97 (P < 0.001), but in 17 patients, EEOT was not possible because triggering of the ventilator by the patient's inspiratory effort. In conclusion, in mechanically ventilated patients with acute circulatory failure Δ VTIMFC and Δ VTI EEOT accurately predicts fluid responsiveness.

Comparison of laser speckle contrast imaging with laser Doppler perfusion imaging for tissue perfusion measurement.

Laser-based tissue perfusion monitoring techniques have been increasingly used in animal and human research to assess blood flow. However, these techniques use arbitrary units, and knowledge about their comparability is scarce. This study aimed to model the relationship between laser speckle contrast imaging (LSCI) and laser Doppler perfusion imaging (LDPI), for measuring tissue perfusion over a wide range of blood flux values. Fifteen healthy volunteers (53% female, median age 29 [IQR 22-40] years) were enrolled in this study. We performed iontophoresis with sodium nitroprusside on the forearm to induce regional vasodilation to increase skin blood flux. Besides, a stepwise vascular occlusion was applied on the contralateral upper arm to reduce blood flux. Both techniques were compared using a linear mixed model analysis. Baseline blood flux values measured by LSCI were 33 ± 6.5 arbitrary unit (AU) (Coefficient of variation [CV]=20%) and by LDPI 60 ± 11.5AU (CV=19%). At the end of the iontophoresis protocol, the regional blood flux increased to 724 ± 412% and 259 ± 87% of baseline measured by LDPI and LSCI, respectively. On the other hand, during the stepwise vascular occlusion test, the blood flux reduced to 212 ± 40% and 412 ± 177% of its baseline at LDPI and LSCI, respectively. A strong correlation was found between the LSCI and LDPI instruments at increased blood flux with respect to baseline skin blood flux; however, the correlation was weak at reduced blood flux with respect to baseline. LSCI and LDPI instruments are highly linear for blood flux higher than baseline skin blood flux; however, the correlation decreased for blood flux lower than baseline. This study's findings could be a basis for using LSCI in specific patient populations, such as burn care.

The influence of gender differences of skin microhemodynamics parameters assessed in heating and occlusion tests

Introduction. The results of studies devoted to the influence of biological sex on microhemodynamic parameters are ambiguous. Today no studies of sex-specific microhemodynamics evaluated by the new incoherent optical fluctuation flowmetry method (IOFF) have been reported. Objective – to investigate the sex-specific differences of microhemodynamics assessed by the IOFF method in healthy volunteers. Materials and Methods. 27 healthy volunteers (10 men and 17 women) were included in the study. The groups were comparable by sex, age, and main clinical parameters. Perfusion was measured by the IOFF method. Parameters were evaluated while performing an occlusion test on the hand and a local heating test on the dorsum of the foot and the toe. Microcirculation reactivity was calculated as a relative increase of perfusion response to the vasodilation stimulus. Results. Women had significantly lower median baseline perfusion than men on the hand and on the dorsum of the foot (hand: 10 [6; 13] PU vs. 15 [10; 19] PU, p = 0.035; foot: 0.78 [0.68; 0.97] PU vs. 1.13 [0.99; 1.29] PU, p = 0.003). Women were demonstrated to have significantly higher reactivity response to thermal and occlusive stimuli than men (p &lt; 0.05). Thus, at the third minute of heating, women had perfusion increased 5.39 [4.32; 6.64] times and men had 3.47 [3.13; 4.65] times (p = 0.018); after the release of the occlusion women had perfusion increased 1.93 [1.37; 3.02] times and men had 1.14 [1.01; 1.74] times (p = 0.011). Conclusion. Healthy women had been shown to have higher reactivity of microhemodynamics than men. A lower cardiovascular risk women have compared to men could be caused by sex-specific features of endothelium function.

Functional state of skin microvascular bed according to laser doppler flowmetry in patients with arterial hypertension combined with hypercholesterolemia

Introduction. The great importance of risk factors, such as arterial hypertension (AH) and low-density lipoprotein cholesterol (LDL-H), for development of cardiovascular diseases, makes highly relevant to obtain the data of the nature of microcirculation (MC) changes that are a key link of maintaining homeostasis under their concomitant influence. Aim – to evaluate functional state of skin microvascular bed using laser Doppler flowmetry in patients with arterial hypertension (AH) and combined with hypercholesterolemia. Materials and Methods. The study involved 37 practically healthy volunteers and 94 patients with 2–3 stage of AH, which were divided into 2 groups: Gr.1 with LDL-CH level ≤3.5 mmol/l (n = 35) and Gr.2 with LDL-H level &gt;3.5 mmol/l (n = 59). MC of the forearm skin was assessed by laser Doppler flowmetry. Parameters of basal blood flow, the amplitude-frequency spectrum of its fluctuations, nutritional MC, and parameters of occlusion test were evaluated. Results. Analyzing rhythm structure of blood flow fluctuations, statistically significant decrease in standardized parameters of their amplitude in endothelial and myogenic frequency ranges was revealed in patients with elevated LDL-CH levels compared to patients of Gr.1 by 19.7 % and 9.7 % (р = 0.045), respectively, which indicated weakening of endothelial function and constriction of precapillary segment of MC. These changes were accompanied by decrease in reserve of microvascular blood flow by 9.1 % in Gr.2 of patients (p = 0.044) with pronounced trend towards reduction of capillary perfusion and activation of blood flow through arteriolovenular shunts. Conclusion. More pronounced functional disorders of MC, characterized by endothelial dysfunction, constriction of precapillary segment, and decrease in reserve potential of tissue hemoperfusion were revealed in AH patients with atherogenic hyperlipidemia vs AH patients.

Therapeutic Neurointervention through Transradial Approach: Preliminary Experience from a Tertiary Care Center

Abstract Aim The aim of this study was to assess the safety and feasibility of radial access for therapeutic neurointervention procedures. Methods The retrospective evaluation of 20 patients taken for therapeutic neurointervention through transradial access at our institute was done from July 2021 to April 2022. Results Therapeutic neurointervention procedures were attempted in 20 patients (age, 24–74 years; mean age, 48.4 years; 13 (65%) females using a transradial approach. The radial artery's mean diameter was 2.135 mm. The right radial access was taken in 18 (90%) cases. Indications for treatment were ruptured aneurysm in 13 (65%), mechanical thrombectomy in 5 (25%), flow diversion for a recanalized aneurysm in 1 (5%), and balloon occlusion test in 1 (5%) case. The procedure was successful through the transradial approach in 18 (90%) procedures. Failure was seen in two cases that were completed after conversion to the transfemoral approach. The reason for access conversion was a severe spasm in both cases. No significant access site complications were seen in the study cohort. Conclusion A radial access route is a promising approach for therapeutic interventions with a high success rate and minimal access site complications. Interventionists should get accustomed to this approach as primary or alternative access for neurointervention.

Preoperative Balloon Occlusion Test of the Carotid Artery and Preoperative Tumor Embolization on Paraganglioma of Carotid Body: 20-Year Experience in a Single Institute and Literature Review

Background and Objectives Carotid body paraganglioma is the common type of carotid body tumor for which angiography, carotid artery balloon occlusion test (BOT) and tumor embolization could be considered before the surgery. We analyzed cases in a single institute and reviewed related literature to investigate the necessity of these preoperative examinations.Subjects and Method Medical records of patients who were diagnosed with paraganglioma were retrospectively analyzed from 2000 to 2019.Results Sixteen patients were identified. Of the total, 14 patients underwent surgery at this institute, and 13 underwent angiography. Of the 13 patients who underwent angiography, 6 patients underwent carotid artery BOT, and 12 patients underwent tumor embolization. The average tumor size of 6 patients who underwent carotid artery BOT was 28.7 mm, and 8 patients who did not undergo carotid artery BOT was 30.1 mm. The average tumor size of 12 patients who underwent tumor embolization was 29.4 mm. Two patients did not undergo tumor embolization, and their average tumor size was 30 mm. In 1 patient, both preoperative angiography and carotid artery BOT were performed, but tumor embolization was not performed due to spasm of tumor vessels.Conclusion Preoperative carotid artery BOT can be performed to reduce side effects in patients with the potential for carotid resection. In addition, tumor embolization is performed regardless of tumor size. By reducing the amount of bleeding during surgery and reducing the size of the tumor, it is possible to secure an appropriate surgical field of view to facilitate operation during surgery; however, its effectiveness needs to be clearly identified.

Adaptive Active Positioning of Camellia oleifera Fruit Picking Points: Classical Image Processing and YOLOv7 Fusion Algorithm

Camellia oleifera fruits are randomly distributed in an orchard, and the fruits are easily blocked or covered by leaves. In addition, the colors of leaves and fruits are alike, and flowers and fruits grow at the same time, presenting many ambiguities. The large shock force will cause flowers to fall and affect the yield. As a result, accurate positioning becomes a difficult problem for robot picking. Therefore, studying target recognition and localization of Camellia oleifera fruits in complex environments has many difficulties. In this paper, a fusion method of deep learning based on visual perception and image processing is proposed to adaptively and actively locate fruit recognition and picking points for Camellia oleifera fruits. First, to adapt to the target classification and recognition of complex scenes in the field, the parameters of the You Only Live Once v7 (YOLOv7) model were optimized and selected to achieve Camellia oleifera fruits’ detection and determine the center point of the fruit recognition frame. Then, image processing and a geometric algorithm are used to process the image, segment, and determine the morphology of the fruit, extract the centroid of the outline of Camellia oleifera fruit, and then analyze the position deviation of its centroid point and the center point in the YOLO recognition frame. The frontlighting, backlight, partial occlusion, and other test conditions for the perceptual recognition processing were validated with several experiments. The results demonstrate that the precision of YOLOv7 is close to that of YOLOv5s, and the mean average precision of YOLOv7 is higher than that of YOLOv5s. For some occluded Camellia oleifera fruits, the YOLOv7 algorithm is better than the YOLOv5s algorithm, which improves the detection accuracy of Camellia oleifera fruits. The contour of Camellia oleifera fruits can be extracted entirely via image processing. The average position deviation between the centroid point of the image extraction and the center point of the YOLO recognition frame is 2.86 pixels; thus, the center point of the YOLO recognition frame is approximately considered to be consistent with the centroid point of the image extraction.

Effects of Inspiratory Muscle Training on Muscle Oxygenation during Vascular Occlusion Testing in Trained Healthy Adult Males

To determine the effects of IMT on vascular and metabolic muscle changes and their relationship to changes in physical performance. Physically active men were randomly placed into an experimental (IMTG; n = 8) or IMT placebo group (IMTPG; n = 6). For IMT, resistance load was set at 50% and 15% of the maximum dynamic inspiratory strength (S-Index), respectively. Only the IMTG's weekly load was increased by 5%. In addition, both groups carried out the same concurrent training. Besides the S-Index, a 1.5-mile running test, spirometry, and deoxyhemoglobin (HHbAUC during occlusion) and reperfusion tissue saturation index (TSIMB and TSIMP: time from minimum to baseline and to peak, respectively) in a vascular occlusion test were measured before and after the 4-week training program. In addition, resting heart rate and blood pressure were registered. IMTG improved compared to IMTPG in the S-Index (Δ = 28.23 ± 26.6 cmH2O), maximal inspiratory flow (MIF: Δ = 0.91 ± 0.6 L/s), maximum oxygen uptake (Δ = 4.48 ± 1.1 mL/kg/min), 1.5-mile run time (Δ = -0.81 ± 0.2 s), TSIMB (Δ = -3.38 ± 3.1 s) and TSIMP (Δ = -5.88 ± 3.7 s) with p < 0.05. ΔVO2max correlated with S-Index (r = 0.619) and MIF (r = 0.583) with p < 0.05. Both ΔTSIMB and TSIMP correlated with ΔHHbAUC (r = 0.516 and 0.596, respectively) and with Δ1.5-mile run time (r = 0.669 and 0.686, respectively) with p < 0.05. IMT improves vascular function, which is related to additional improvements in physical performance.

Reliance Upon Contextual Information Can Impede Visual Anticipation

This study investigated whether skilled batsmen in a state cricket pathway could anticipate ball types when congruency of field-placings was manipulated with a bowler’s action. Twenty-four male cricket batsmen were recruited who had played either first-class cricket (n = 6), were part of under 17 (n = 8) or under 19 (n = 10) state cricket squads. Participants completed a video-based temporal occlusion test where they were required to anticipate ball types from a swing bowler. In condition one, contextual field-placing information was presented to be congruent with the delivery type and bowler’s action, whilst in condition two it was incongruent. Results did not reveal skill level differences across conditions for anticipation. In the congruent condition, all skill groups predicted above chance level at the beginning and end of the bowler’s delivery stride. In the incongruent condition, first-class players predicted above chance at the beginning of the bowler’s delivery stride, and to a higher magnitude above chance compared to other skill groups at ball release. Under 17 and 19 players could not predict above chance at the start of the bowler’s delivery stride with their magnitude of prediction lower than first-class players at ball release. Results indicate skilled batsmen find it challenging to integrate contextual and kinematic information to anticipate. This is likely due to greater emphasis placed upon contextual information in part supplied by data analysts. Findings have theoretical and practical implications respectively for lower body positioning for bat-ball interception and perceptual training to improve pick-up of kinematic cues. Highlights Skilled batsmen in a high-performance state cricket pathway could integrate congruent field-placings and bowler kinematics to anticipate ball types. First-class batsmen could integrate incongruent field-placing information to the start, but not the end, of the bowler’s delivery action to anticipate ball types. Under 17 and 19 batsmen could not integrate incongruent field-placings to bowler kinematic to anticipate ball types. Skilled batsmen who cannot use kinematic information to anticipate ball types should be given visual-perceptual simulation training to accelerate performance.

Exploring the relationship between capillary refill time, skin blood flow and microcirculatory reactivity during early resuscitation of patients with septic shock: a pilot study.

Capillary refill time (CRT), a costless and widely available tool, has emerged as a promising target to guide septic shock resuscitation. However, it has yet to gain universal acceptance due to its potential inter-observer variability. Standardization of CRT assessment may minimize this problem, but few studies have compared this approach with techniques that directly assess skin blood flow (SBF). Our objective was to determine if an abnormal CRT is associated with impaired SBF and microvascular reactivity in early septic shock patients. Twelve septic shock patients were subjected to multimodal perfusion and hemodynamic monitoring for 24h. Three time-points (0, 1, and 24h) were registered for each patient. SBF was measured by laser doppler. We performed a baseline SBF measurement and two microvascular reactivity tests: one with a thermal challenge at 44°C and other with a vascular occlusion test. Ten healthy volunteers were evaluated to obtain reference values. The patients (median age 70years) exhibited a 28-day mortality of 50%. Baseline CRT was 3.3 [2.7-7.3] seconds. In pooled data analysis, abnormal CRT presented a significantly lower SBF when compared to normal CRT [44 (13.3-80.3) vs 193.2 (99.4-285) APU, p = 0.0001]. CRT was strongly associated with SBF (R2 0.76, p < 0.0001). An abnormal CRT also was associated with impaired thermal challenge and vascular occlusion tests. Abnormal CRT values observed during early septic shock resuscitation are associated with impaired skin blood flow, and abnormal skin microvascular reactivity. Future studies should confirm these results.

Risk factors for cardiovascular diseases in patients received complex treatment for cranial and craniospinal tumors in childhood

Aim. To study the traditional risk factors for cardiovascular disease (CVD), indicators of endothelial function and exercise tolerance in patients received complex treatment for cranial and craniospinal tumors in childhood, including radiation therapy.Material and methods. We compared examination data of 48 patients who underwent treatment for brain tumors using cranial and craniospinal irradiation in childhood (mean age, 21,7±4,3 years, mean period after the end of treatment, 6,9±5,4 years), and 20 healthy volunteers. Examination methods included assessment of lipid profile, vascular stiffness and endothelial function using the Photoplethysmography and occlusion test, cardiopulmonary test, and in patients who underwent craniospinal irradiation, also echocardiography and duplex ultrasound of extracranial arteries.Results. Compared to healthy individuals, patients after a brain tumor were found to have lower blood pressure, higher heart rate (HR), significantly lower exercise performance (peak oxygen consumption, 19,8±6,4 ml×min-1×kg vs 30,3±5,8 ml×min-1×kg, p&lt;0,0001) and a higher prevalence of dyslipidemia (56% vs 5%, p&lt;0,0001), as well as an increase in the augmentation index, indicating higher stiffness of large vessels (-7,3±16,3 vs -20,3±7,9, p=0,001), and a trend towards a decrease in the occlusion index (p=0,051). Echocardiography and duplex ultrasound revealed no radiation-associated abnormalities.Conclusion. Determining the mechanisms and prognostic significance of the identified risk factors for CVD (dyslipidemia, decreased exercise tolerance, increased heart rate and vascular stiffness) in this category of patients requires further research. Regular monitoring of risk factors, primarily the lipid profile, and the use of preventive measures for individuals with an increased risk of CVD should be recommended.

Metabolic and microvascular function assessed using near-infrared spectroscopy with vascular occlusion in women: age differences and reliability.

What is the central question of this study? Can the near-infrared spectroscopy with vascular occlusion test (NIRS-VOT) reliably measure skeletal muscle metabolic and microvascular function in women? What is the main finding and its importance? The NIRS-VOT can be used as a reliable technique for the assessment of skeletal muscle metabolism and microvascular function in women, with reliability being generally greater in younger women. These findings have important implications for the planning and development of future studies employing the NIRS-VOT in women, and provide insights into the effects of age on these parameters in women specifically. We investigated the test-retest reliability of, and age-related differences in, markers of skeletal muscle metabolism and microvascular function derived from the near-infrared spectroscopy with vascular occlusion test (NIRS-VOT) in younger women (YW) and middle-aged and older women (MAOW). Seventeen YW (age 23±4years) and 17 MAOW (age 59±8years) completed this study. Participants completed identical experimental visits separated by ∼4weeks during which the NIRS-VOT was used to quantify the occlusion slope, minimum and maximum tissue saturation, ischaemic index, reperfusion magnitude, the reperfusion and 10-s reperfusion slopes (slope 2 and slope 210-s ), time to max tissue saturation, and area under the reperfusion curve using the local tissue oxygen saturation signal. Except for slope 210-s (intraclass correlation coefficient (ICC)=0.37; coefficient of variation (CV)=31%), time to max tissue saturation (ICC=0.21), and ischaemic index (ICC=0.37) for MAOW, all of the NIRS variables demonstrated good to excellent relative reliability for the YW (ICCs=0.74-0.86) and the MAOW (ICCs=0.51-0.87), with CVs of 2-21% and 2-22%, respectively. The occlusion slope was significantly lower, indicating accelerated deoxygenation, while maximum tissue saturation, reperfusion magnitude, and ischaemic index were significantly higher in YW versus MAOW. No other group differences were found. In conclusion, our data support the use of the NIRS-VOT as a simple, reliable, non-invasive technique for the assessment of peripheral skeletal muscle metabolism and microvascular function in women, with the reliability being generally greater in YW versus MAOW. Further, our data suggest that ageing is associated with lower skeletal muscle metabolism and microvascular hyperaemic responsiveness in women.

Internal carotid artery embolization in endoscopic salvage surgery for recurrent nasopharyngeal carcinoma: a single-center retrospective study

Objective: To evaluate the efficiency of internal carotid artery (ICA) embolization technology in endoscopic salvage surgery for recurrent nasopharyngeal carcinoma (rNPC) invading the ICA. Methods: From January 2016 to March 2021, 83 patients with rNPC who invaded the ICA and underwent endoscopic extended nasopharyngectomy were retrospectively collected from the Eye & ENT Hospital in Fudan University, including 60 males and 23 females. The age of the patients ranged from 27 to 77 years. The standard of ICA invasion was that the distance from the lesion to the ICA on enhanced MRI was ≤ 1.8 mm. The clinical characteristics, ICA management strategy and survival prognosis of patients were analyzed, and the effectiveness of ICA embolization was evaluated. Kaplan-Meier method was used to calculate the survival rate and Log-rank test was used to compare the difference. Results: In 83 patients with rNPC, there were 13 patients with rT2, 38 patients with rT3, 32 patients with rT4, and 16 patients had lymph node metastasis. A total of 37 patients (44.6%) underwent ICA coil embolization before surgery, of which 2 cases underwent external carotid-middle cerebral artery artery bypass grafting and ICA embolization due to positive balloon occlusion test (BOT). Patients with positive surgical margin accounted for 24.1% (20/83). Among them, patients with rT4 and patients without ICA embolization had a higher positive rate of surgical margin (P value was 0.001, 0.043, respectively). The 3-year overall survival (OS) and progression free survival (PFS) rate of all patients was 46.5% and 26.7%, respectively. In addition, the 3-year OS and PFS of patients with ICA embolization was significantly higher than those without ICA embolization, respectively (69.1% vs 27.8%, P=0.003; 33.9% vs 18.9%, P=0.018). Only 2 patients (2/37, 5.4%) had cerebral infarction complications after coil embolization of the affected ICA due to negative BOT. Conclusion: Preoperative ICA embolization can be used to treat patients with rNPC invading the ICA, improve the total removal rate and survival rate of patients, which is an effective salvage treatment.

ALLERGIC CONTACT DERMATITIS TO 2-OCTYL CYANOACRYLATE CONFIRMED BY PATCH TESTING: A PEDIATRIC CASE SERIES

<h3>Introduction</h3> 2-octyl cyanoacrylate is a tissue adhesive commonly used to close wounds. While there have been multiple case reports regarding allergic contact dermatitis (ACD) to 2-octyl cyanoacrylate in the adult population, there is little in the literature regarding ACD to 2-octyl cyanoacrylate in the pediatric population. <h3>Methods</h3> A retrospective chart review was completed to identify patients who underwent patch testing to 2-octyl cyanoacrylate at a pediatric tertiary care center within the past 5 years. <h3>Results</h3> A total of 5 pediatric patients met inclusion criteria. All patients had a history of atopy. Four patients used 2-octyl cyanoacrylate previously without documented adverse reaction. Two patients had open patch testing and 3 had traditional occlusive patch testing. All patients were tested to multiple substances, and 3 of the 5 patients had reactions to other allergens in addition to 2-octyl cyanoacrylate. Four of five patients had reactions consisting of either erythema, pruritus, or pain within 24 hours of 2-octyl cyanoacrylate placement. All patients had positive reactions at 48 hours and strong or extreme positive reactions on subsequent readings. One patient required oral steroids for relief and the other 4 were treated with topical steroids. <h3>Conclusion</h3> 2-octyl cyanoacrylate can be a cause of ACD in pediatric patients. While reactions concerning for ACD can occur with many surgical products, a thorough history and patch testing can aid in identifying specific causative agents.

Судинні порушення у хворих на ревматичні хвороби після перенесеного COVID-19

The article briefly summarizes data on the role of micro- and macrocirculatory disorders in the pathogenesis of COVID-19. Focused attention on similarities of clinical and pathogenetic features of rheumatic diseases, COVID-19 and its complications. The review analyzed and compared the data of the assessment of the main instrumental studies of the functional state of blood vessels in patients with rheumatic diseases in general and in patients with rheumatic diseases who suffered from COVID-19 (capillaroscopy and occlusion test). A conclusion was made about the presence of endothelial dysfunction in rheumatic diseases and its features in patients with rheumatic diseases after transmission of COVID-19. This leads to the opinion about the expediency of timely detection of secondary disorders of the functional state of blood vessels in patients with rheumatic diseases who are convalescents of COVID-19, and justifies the use of an occlusion test for this purpose. No conflict of interests was declared by the authors.

Automatic Detection of Cracks in Cracked Tooth Based on Binary Classification Convolutional Neural Networks.

Cracked tooth syndrome is a commonly encountered disease in dentistry, which is often accompanied by dramatic painful responses from occlusion and temperature stimulation. Current clinical diagnostic trials include traditional methods (such as occlusion test, probing, cold stimulation, etc.) and X-rays based medical imaging (periapical radiography (PR), cone-beam computed tomography (CBCT), etc.). However, these methods are strongly dependent on the experience of the clinicians, and some inconspicuous cracks are also extremely easy to be overlooked by visual observation, which will definitely affect the subsequent treatments. Inspired by the achievements of applying deep convolutional neural networks (CNNs) in crack detection in engineering, this article proposes an image-based crack detection method using a deep CNN classifier in combination with a sliding window algorithm. A CNN model is designed by modifying the size of the input layer and adding a fully connected layer with 2 units based on the ResNet50, and then, the proposed CNN is trained and validated with a self-prepared cracked tooth dataset including 20,000 images. By comparing validation accuracy under seven different learning rates, 10−5 is chosen as the best learning rate for the following testing process. The trained CNN is tested on 100 images with 1920 × 1080-pixel resolutions, which achieves an average accuracy of 90.39%. The results show that the proposed method can effectively detect cracks in images under various conditions (stained, overexplosion, images affected by other diseases). The proposed method in this article provides doctors with a more intelligent diagnostic solution, and it is not only suitable for optical photographs but also for automated diagnosis of other medical imaging images.

Evaluation of an innovative low flow oxygen blender system for global access.

BackgroundSafe and effective oxygen delivery methods are not available for the majority of infants and young children globally. A novel oxygen blender system was designed to accurately deliver concentration-controlled, oxygen-enriched air to hypoxemic children up to age five. The system does not require compressed medical air, is compatible with both oxygen tanks and oxygen concentrators, and is low cost. This is the first study that tested the performance of the innovative oxygen blender system.MethodsThe performance of the oxygen blender system was assessed in vitro based on delivered oxygen levels and flow rates with an oxygen tank, an oxygen tank using a nasal occlusion model, and an oxygen concentrator.ResultsThe measured %O2 of the performance test was within ± 5% of full scale (FS) of the target value across all flows and all nasal cannulas. Occlusion testing demonstrated that 50% occlusion did not significantly affect the system outputs. The oxygen blender system was shown to be compatible with both oxygen tanks and oxygen concentrators.ConclusionsThe novel oxygen blender system accurately controls oxygen concentrations and blended air flow rates, and is compatible with both oxygen tanks and oxygen concentrators. This innovation may be an opportunity for improved infant and child oxygen treatment worldwide.

Case report: Rare abernethy malformation with hepatopulmonary syndrome in a pediatric patient

Abernethy malformation is a rare abnormality of the hepatic portal vein system with non-specific and diverse clinical manifestations. Here, we described a case of abernethy malformation with hepatopulmonary syndrome in a 10-year-old girl. On physical examination, cyanosed lips and acropachy could be found. Her oxygen saturation fluctuated at 89–94%, and the fasting blood ammonia was 98 umol/L. Furthermore, there were abnormalities in the imaging. The microbubble test with contrast echocardiography was positive. Computer tomography angiography (CTA) showed the splenic vein, and the superior mesenteric drained directly into the inferior vena cave after confluence. The same result was also observed in delayed splenic arteriography. Then, we discovered a tiny branch of the intrahepatic portal vein by the inferior vena cava balloon occlusion test, which could also show the confluence of the splenic vein and superior mesenteric vein with the inferior venacave. According to the evidence above, we concluded that the girl was a patient of type II abernethy malformation. For the severe dysplasia of the portal vein, the girl accepted partial ligation of portosystemic shunt and Rex shunt, which improved her oxygen saturation and exercise tolerance.