Transcutaneous Partial Pressure Of Oxygen Research Articles

A STUDY TO DETERMINE THE SHORT TERM OUTCOME OF INFRAINGUINAL BYPASS FOR CRITICAL LIMB ISCHEMIA

Introduction: Critical limb ischemia is defined as persistent, recurring ischemic rest pain requiring opiate analgesia for at least 2 weeks, or ulceration or gangrene of the foot or toes and ankle systolic pressure lower than 50 mm Hg or toe systolic pressure lower than 30 mm Hg. CLI is a clinical diagnosis and it should be confirmed early and objectively through ABI, toe systolic pressure or transcutaneous partial pressure of oxygen (TcPO2). Once the diagnosis is confirmed, the goals of treating CLI are to relieve ischemic pain, heal ischemic ulcers, prevent limb loss, improve patient function and QOL and prolong survival. Revascularization will help to achieve these goals. The aim of the study is to assess the outcome of infra-inguinal bypass surgery in all PVD patients who presented to our General Surgery department with CLI. Objectives: To assess the following in CLI after infra-inguinal bypass surgery: 1) Wound healing 2) Limb salvage 3) Self assessed degree of ambulation 4) Primary patency of graft-using arterial doppler Methods: This is a single directional cohort study conducted in 48 patients who presented to Amala General Surgery Department with critical limb ischemia, who underwent infra-inguinal bypass surgery with reversed saphenous vein graft. PVD patients with CLI were assessed preoperatively. Periodic assessment was also done during postoperative period at 1 month and 6 months. Primary graft patency was checked at 6 months using arterial doppler. These patients were monitored closely during the pre-operative period, during surgery and postoperative period. They were also followed up at 1 and 6 months. The study duration is 18 months, from January 2018 to June 2019. Results and Discussion: From January 2018 to June 2019, 48 patients (37 males, mean age of 65 years) underwent infrainguinal bypasses (37 femoropopliteal, 11 femorodistal) for CLI (12 Fontaine III and 36 Fontaine IV).There was no perioperative mortality. The mean duration of hospitalization was 10.542 with standard deviation of 3.2809.Wound healing observed at 1 month is 39.58%, which was increased to 77.08 % at the end of 6 months (Mc Nemar Test p value=0.0001).Limb salvage attained at the end of 6 months is 87.5%.Ambulatory status of the patients were assessed at the end of 1 month after surgery and only 2% were ambulatory outdoors, 90 % were ambulating indoors and 8% were non-ambulatory. Total ambulatory status post-surgery (indoor and outdoor combined), came around 92% at 1 month. At 6 months post-surgery, 19 % of patients were ambulating outdoors, 60 % were ambulating indoors and 21 % were non-ambulatory. Total ambulatory status at 6 months (indoor and outdoor combined) post-surgery came around 79 % (Mc Nemar Test p value = 0.001) and primary patency of the graft at 6 months for our cohort is 79.2%. Conclusion: This Study includes 48 patients with CLI who has undergone infrainginal bypass with reversed saphenous vein graft. 87.5% limb salvage, 77.08% wound healing at 6 months, 79% was ambulatory status at 6 months and 79.2% primary graft patency were attained.. 7 out of 8 CLI patients treated surgically has limb salvage and good functional status.

Gender-Related Difference in Skin Oxygenation in Young Patients with Uncomplicated Type 1 Diabetes.

Gender, through genetic, epigenetic and hormonal regulation, is an important modifier of the physiological mechanisms and clinical course of diseases. In diabetes mellitus, there are gender differences in incidence, prevalence, morbidity, and mortality. This disease also has an impact on the microvascular function. Therefore, this cross-sectional study was designed to investigate how gender affects the cutaneous microcirculation. We hypothesized that gender should be an important factor in the interpretation of capillaroscopy and transcutaneous oxygen saturation results. The study group consisted of 42 boys and 55 girls, uncomplicated diabetic pediatric patients. Females (F) and males (M) did not differ in terms of age, age at onset of diabetes, or diabetes duration. Furthermore, they did not differ in metabolic parameters. The comparison showed that group F had lower BP, higher pulse, and higher HR than group M. Group F had significantly lower creatinine and hemoglobin levels than group M. In children and adolescents with type 1 diabetes without complications, there was a gender difference in microcirculatory parameters. The resting transcutaneous partial pressure of oxygen was significantly higher in females than in males. However, there were no gender-related differences in basal capillaroscopic parameters or vascular reactivity during the PORH test. Our results indicate that studies investigating the structure and function of the microcirculation should consider the role of gender in addition to known cofactors such as puberty, body mass index, physical activity, and cigarette smoking.

TcPO2 changes are more pronounced than SpO2 changes during simulated altitude changes in a hypobaric oxygen chamber: a nonrandomized controlled trial

Abstract Background Hypoxia is a significant risk factor of hypertension. However, no studies have used transcutaneous tissue partial pressure of oxygen (TcPO2) and partial pressure of carbon dioxide (TcPCO2) monitors to measure the respective partial pressures in healthy individuals. Oxygen saturation (SpO2) is often used for traditional monitoring of vital signs. This study investigated the changes in TcPO2 and SpO2 values during rapid changes in altitude. The trial was registered at ClinicalTrials.gov (registration no. NCT06076057). Methods Healthy adult volunteers were instructed to sit vertically in a hypobaric oxygen chamber, which ascended from 0 m to 2500 m at a uniform speed within 10 min. The Danish Radiometer TCM4 was used to measure TcPO2 and TcPCO2 with the ventral side of the upper arm as the measurement site. The Shenzhen Kerokan P0D-1 W pulse oximeter was used to measure heart rate and SpO2, with values recorded once every 500 m. Results Altogether, 49 healthy volunteers were recruited between March 2023 and August 2023. With increasing altitude, TcPO2 and SpO2 decreased significantly (P < 0.01). During the ascent from 0 m, TcPO2 began to change statistically at 500 m (P < 0.05), whereas SpO2 began to change statistically at 1000 m (P < 0.05). At the same altitude, the difference in TcPO2 was greater than the difference in SpO2. At 1000 m, there were statistically significant changes in TcPO2 and SpO2 (P < 0.001). At altitudes >500 m, statistical significance was identified between TcPO2 in both sexes (P < 0.05). Statistical significance in TcPCO2 and heart rate was observed at the different elevations (P < 0.05). Conclusion In acutely changing low-pressure hypoxic environments, TcPO2 changed more dramatically than SpO2.

Electrical stimulation of the lower eyelid orbicularis oculi muscle improves periocular dark circles.

We developed and tested the safety and efficacy of a cosmetic device to improve dark circles using electrical muscle stimulation of the orbicularis oculi muscle. Overall, 18 participants (36 eyes) were studied. The following five items were evaluated before and after the intervention:(1) the Clinical Dark Circle Score using clinical findings and photographs, (2) transcutaneous oxygen partial pressure (TcPO2) on the lower eyelid, (3) thermography, (4) two-dimensional laser blood flowmetry, and (5) spectrophotometry. The mean score at baseline was 2.0±0.90 (mean±standard deviation), and that at the end of the study was 1.2±1.0 (Wilcoxon signed-rank sum test, p<0.0001), indicating a significant reduction. The spectrophotometer showed a significant decrease in a* and L* values before and after use (Wilcoxon signed-rank sum test, p<0.0001). There was also a weak negative correlation between the change in score and the change in blood flow and TcPO2 measured using a laser perfusion device (Spearman's rank correlation coefficient, r=-0.32 and -0.39, respectively). Stratified analysis of the baseline score showed a strong negative correlation between the change in score and the change in spectrophotometric a* in the subjects/group with mild periocular dark circles (Spearman's rank correlation coefficient, r=-0.46). Contrastingly, no correlation was observed for any of the measurements in the subjects/group with severe periocular dark circles. After 1 month, no device-related ophthalmic adverse events were observed in any of the participants. Electrical muscle stimulation could improve periocular dark circles, especially in the subjects/group with mild periocular dark circles, and was safe.

A portable optical pulsatile flowmetry demonstrates strong clinical relevance for diabetic foot perfusion assessment.

We present a robust, cost-effective (<2000 USD), and portable optical diffuse speckle pulsatile flowmetry (DSPF) device with a flexible handheld probe for deep tissue blood flow measurement in the human foot as well as a first-in-man observational clinical study using the proposed optical device for tissue ischemia assessment and peripheral artery disease (PAD) diagnosis. Blood flow in tissue is inherently pulsatile in nature. However, most conventional methods cannot measure deep tissue-level pulsatile blood flow noninvasively. The proposed optical device can measure tissue-level pulsatile blood flow ∼6 mm underneath the skin surface. A new quantitative tissue perfusion index (TPIDSPF) based on frequency domain analysis of the pulsatile blood flow waveform is defined to assess tissue ischemia status. Through a clinical study involving 66 subjects, including healthy individuals and diabetes patients with and without PAD, TPIDSPF demonstrated strong correlations of 0.720 with transcutaneous tissue partial oxygen pressure (TcPO2) and 0.652 with toe-brachial index (TBI). Moreover, among the three methods, TPIDSPF demonstrated the highest area under the curve for PAD diagnosis among diabetes patients, with a notable value of 0.941. The promising clinical results suggest that the proposed optical method has the potential to be an effective clinical tool for identifying PAD among the diabetic cohort.

Comparative Analysis of the Efficacy of Spinal Cord Stimulation and Traditional Debridement Care in the Treatment of Ischemic Diabetic Foot Ulcers: A Retrospective Cohort Study.

Spinal cord stimulation (SCS) is an effective treatment for diabetic peripheral neuropathy. The purpose of this study was to investigate the effectiveness of SCS in the treatment of ischemic diabetic foot ulcers. In this retrospective study, the SCS group comprised 102 patients with ischemic diabetic foot who were treated with SCS for foot ulcers and nonhealing wounds due to severe lower limb ischemia. The traditional debridement care (TDC) group comprised 104 patients with ischemic diabetic foot who received only TDC. Strict screening criteria were applied. The assignment of patients to either group depended solely on their willingness to be treated with SCS. Secondary end points were transcutaneous partial pressure of oxygen (PtcO 2 ), ankle-brachial index (ABI), and color Doppler of the lower limb arteries in the feet at 6 months and 12 months after treatment. The primary end point was the amputation. The dorsal foot PtcO 2 and ABI of the patients in the SCS group were significantly improved at 6 months and 12 months postoperation ( P < .05). The therapeutic efficacy was significantly better than that of the TDC group over the same period of time ( P < .05). The degree of vasodilation of the lower limb arteries (ie, femoral, popliteal, posterior tibial, and dorsalis pedis arteries) on color Doppler was higher in the SCS group than in the TDC group ( P < .05). The odds ratios for total amputation at 6 and 12 months postoperatively in the SCS group were 0.45 (95% CI, 0.19-1.08) and 0.17 (95% CI, 0.08-0.37), respectively, compared with the TDC group. SCS improved symptoms of lower limb ischemia in ischemic diabetic feet and reduced the rate of toe amputation by increasing PtcO 2 , ABI, and arterial vasodilation in the lower limbs.

Central and Peripheral Circulation Differ during Off-Pump Coronary Artery Bypass Grafting.

Off-pump coronary artery bypass grafting (OPCAB) is an alternative to on-pump coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB). During OPCAB, the temporary use of an intracoronary shunt and inotropic medication or catecholamines should keep the central hemodynamics constant. Nevertheless, the need for conversion to on-pump CABG often occurs unexpectedly, most likely due to circulation instability. Circulation instability can appear first in peripheral body parts; therefore, peripheral microcirculation might serve as a predictor for the upcoming conversion to on-pump CABG. We investigated the impact of coronary artery ligation and shunt insertion during OPCAB on cutaneous microcirculation (cLDP) with Laser Doppler Perfusion Technology and transcutaneous oxygen partial pressure ( ). In a pig model of OPCAB, peripheral circulation was evaluated after cLDP (N = 17) and (N = 6) monitoring. Systolic, diastolic, and mean arterial pressure were also observed to prove the independence of perfusion measurement results from hemodynamic parameters. Ligation time during cLDP and monitoring were 101 49 s and 83 33 s, respectively. Shunt time was 11 3 min during cLDP and 13 2 min during measurement. Ligation of the left anterior descending coronary artery (LAD) reduced cLDP significantly to 88 14% (p = 0.007) and to 71 25% (p = 0.038). Inserting a temporary shunt into the LAD significantly improved cLDP (p = 0.006) and (p = 0.015) compared to ligation. cLDP was restored to 99%, and was restored to 91% of the baseline level before ligation. All hemodynamic parameters remained stable and did not change significantly during OPCAB. Although hemodynamic parameters stayed constant, peripheral microcirculation was influenced markedly during OPCAB. Inserting a temporary shut into the LAD leads to a complete normalization of peripheral microcirculation, regarding evaluation by cLDP and .

Autologous angiogenic therapy with cultured mesenchymal stromal cells in platelet-rich plasma for critical limb ischemia

IntroductionThe prevalence of diabetes mellitus is increasing globally, including in Japan. Patients with diabetes often experience microangiopathy and macroangiopathy, which lead to difficult-to-treat foot ulcers and diabetic gangrene. Conventional cellular therapies have limited safety and are invasive. In this study, we investigated the use of cultured autologous mesenchymal stromal cells derived from the bone marrow and grown in platelet-rich plasma as a potential treatment for diabetic complications. MethodsA prospective clinical trial was conducted to assess safety as the primary endpoint and efficacy as the secondary endpoint of the aforementioned therapy in five patients with critical limb ischemia, with or without hemodialysis. ResultsFive patients with critical limb ischemia were enrolled between 2016 and 2019, three of whom underwent hemodialysis. Platelet-rich plasma was obtained from 288 ± 39.6 mL of blood/patient, yielding 31.6 ± 1.67 mL of platelet-rich plasma. Bone marrow aspiration yielded 18.4 ± 4.77 mL/patient, and 4.64 ± 1.51 × 107 cells were incubated for 16 ± 2.8 days to obtain 3.26 ± 0.33 × 107 mesenchymal stromal cells. Although several adverse events were observed, none were directly attributed to cell therapy. Clinical severity, as assessed by both the Fontaine stage and Rutherford category, improved significantly following therapy. This improvement was accompanied by enhancements in the 6-min walking distance, dorsal skin perfusion pressure, ankle transcutaneous partial oxygen pressure, and ankle brachial pressure index. ConclusionAutologous angiogenic therapy with cultured mesenchymal stromal cells derived from the bone marrow and grown in platelet-rich plasma is a safe and feasible, and was expected as a potential treatment for critical limb ischemia.

Comparison of Ankle Brachial Index (ABI), Toe Brachial Index (TBI), and Trans-Cutaneous Partial Pressure of Oxygen (TcPO2) in Prediction of Limb Outcome Among Patients with Diabetic Foot Ulcers (DFUs)

Comparison of Ankle Brachial Index (ABI), Toe Brachial Index (TBI), and Trans-Cutaneous Partial Pressure of Oxygen (TcPO2) in Prediction of Limb Outcome Among Patients with Diabetic Foot Ulcers (DFUs)

Three-dimensional analysis of posttraumatic tibial shaft malunion and correction based on the healthy, contralateral leg

Three-dimensional (3D) analysis and implementation with patient-specific cutting and repositioning blocks enables correction of complex tibial malunions. Correction can be planned using the contralateral side or astatistical model. Patient-specific 3D-printed cutting guide blocks enable aprecise osteotomy and reduction guide blocks help to achieve anatomical reduction. Depending on the type and extent of correction, fibula osteotomy may need to be considered to achieve the desired reduction. a)Poor soft tissue (flap surgery, adherent skin in field of operation); b)infection; c)peripheral artery disease (stageIII andIV classified according to Fontaine, critical transcutaneous oxygen partial pressure, TcPO2); d)general contraindication to surgery. Before surgery, a3D model of both lower legs is created based on computed tomography (CT) scans. Analysis of the deformity based on the contralateral side in a3D computer model (CASPA) and planning of the osteotomy. If the contralateral side also has adeformity, astatistical model can be used. Printing of patient-specific guides made of nylon (PA2200) for the osteotomy and reduction. Surgery is performed in supine position, antibiotic prophylaxis, thigh tourniquet, which is used as needed. Ventrolateral approach to the tibia. Attachment of the patient-specific osteotomy guide, performance of the osteotomy. Reduction using the guide. Fibula osteotomy through alateral approach is performed if the reduction of the tibia is hindered by the fibula. This can be performed freehand or with patient-specific guides. Wound closure. Compartment monitoring. Passive mobilization of the ankle in the cast as soon as the wound healing has progressed. Partial weightbearing in alower leg cast for at least 6-12weeks, depending on the routinely performed radiographic assessment 6weeks postoperatively. Thromboprophylaxis with low molecular weight heparin until cast removal. Patient-specific correction of malunions are generally good. This could be confirmed for distal tibial corrections. For tibial shaft deformities, the final results are still pending. Preliminary results, however, show good feasibility with apseudarthrosis rate of 10% without postoperative infection.

Examination of Lower Limb Microcirculation in Diabetic Patients with and without Intermittent Claudication.

Intermittent claudication is a frequent complaint in lower extremity artery disease, but approximately two thirds of patients are asymptomatic, most of which are diabetic patients. Non-invasive angiological and microrheological tests on diabetic subjects with and without intermittent claudication were performed in the present study. In total, 98 diabetic patients were included and divided into two groups: 20 patients (63.5 ± 8.8 years, 55% men, 45% women) had intermittent claudication, 78 patients (65.5 ± 9.3 years, 61.5% men, 38.5% women) were asymptomatic. Hand-held Doppler ultrasound examination, transcutaneous tissue partial oxygen pressure (tcpO2) measurement, Rydel-Seiffer tuning fork tests, and 6-min walk tests were performed, and erythrocyte aggregation was investigated. Ankle-brachial index (p < 0.02) and tcpO2, measured during provocation tests (p < 0.003) and the 6-min walk test (p < 0.0001), significantly deteriorated in the symptomatic group. A higher erythrocyte aggregation index and faster aggregate formation was observed in claudication patients (p < 0.02). Despite the statistically better results of the asymptomatic group, 13% of these patients had severe limb ischemia based on the results of tcpO2 measurement. Claudication can be associated with worse hemodynamic and hemorheological conditions in diabetic patients; however, severe ischemia can also develop in asymptomatic subjects. Non-invasive vascular tests can detect ischemia, which highlights the importance of early instrumental screening of the lower limbs.

Influence of Face Masks on Physiological and Subjective Response during 130 Min of Simulated Light and Medium Physical Manual Work-An Explorative Study.

Undesirable side effects from wearing face masks during the ongoing COVID-19 pandemic continue to be discussed and pose a challenge to occupational health and safety when recommending safe application. Only few studies examined the effects of continuously wearing a face mask for more than one hour. Therefore, the influence of wearing a medical mask (MedMask) and a filtering facepiece class II respirator (FFP2) on the physiological and subjective outcomes in the course of 130 min of manual work was exploratively investigated. Physical work load and cardiorespiratory fitness levels were additionally considered as moderating factors. Twenty-four healthy subjects (12 females) from three different cardiorespiratory fitness levels each performed 130 min of simulated manual work with light and medium physical workload using either no mask, a MedMask or FFP2. Heart rate, transcutaneous oxygen and carbon dioxide partial pressure (PtcO2, PtcCO2) as well as perceived physical exertion and respiratory effort were assessed continuously at discrete time intervals. Wearing comfort of the masks were additionally rated after the working period. There was no difference in time-dependent changes of physiological outcomes when using either a MedMask or a FFP2 compared to not wearing a mask. A stronger increase over time in perceived respiratory effort occurred when the face masks were worn, being more prominent for FFP2. Physical workload level and cardiorespiratory fitness level were no moderating factors and higher wearing comfort was rated for the MedMask. Our results suggest that using face masks during light and medium physical manual work does not induce detrimental side effects. Prolonged wearing episodes appeared to increase respiratory effort, but without affecting human physiology in a clinically relevant way.

A Prototype Wearable Device for Noninvasive Monitoring of Transcutaneous Oxygen.

Transcutaneous oxygen monitoring is a noninvasive method for measuring the partial pressure of oxygen diffusing through the skin, which strongly correlates with changes in dissolved oxygen in the arteries. Luminescent oxygen sensing is one of the techniques for assessing transcutaneous oxygen. Intensity- and lifetime-based measurements are two well-known methods used in this technique. The latter is more immune to optical path changes and reflections, making the measurements less vulnerable to motion artifacts and skin color changes. Although the lifetime-based method is promising, the acquisition of high-resolution lifetime data is crucial for accurate transcutaneous oxygen measurements from the human body when skin is not heated. We have built a compact prototype along with its custom firmware for the lifetime estimation of transcutaneous oxygen with a provision of a wearable device. Furthermore, we performed a small experiment study on three healthy human volunteers to prove the concept of measuring oxygen diffusing from the skin without heating. Lastly, the prototype successfully detected changes in lifetime values driven by the changes in transcutaneous oxygen partial pressure due to pressure-induced arterial occlusion and hypoxic gas delivery. The prototype resolved a minimum change of 1.34ns in a lifetime that corresponds to ∼0.031mmHg in response to slow changes in the oxygen pressure in the volunteer's body caused by hypoxic gas delivery. The prototype is believed to be the first in the literature to successfully conduct measurements in human subjects using the lifetime-based technique.

Application of extracorporeal shockwave therapy to improve microcirculation in diabetic foot ulcers: A prospective study.

Extracorporeal shockwave therapy (ESWT) can induce wound healing by increasing tissue microcirculation. However, studies on the effect of ESWT on enhancing tissue microcirculation in diabetic foot ulcer (DFU), particularly on when the microcirculation increases after ESWT application, are still lacking. Therefore, we aimed to examine the effectiveness of ESWT in promoting microcirculation in DFU patients in a time-dependent manner. We included 50 feet of 25 patients with type 2 diabetes mellitus and Wagner grade I to II DFU in this study. The affected feet were used as the ESWT group and the unaffected contralateral feet were used as the control group. ESWT was performed in 3 sessions per week for a total of 3 weeks. Transcutaneous partial oxygen pressure (TcPO2) was used to evaluate the tissue microcirculation. The TcPO2 level (>43 mm Hg) in the ESWT group was recovered by the 2nd week of treatment, and statistical significance (P < .05) was demonstrated at the same time. From the 2nd week of ESWT, a significant increase in TcPO2 was observed in Wagner grade I and II DFU. These findings imply that the ESWT may improve microcirculation in patients with Wagner grades I to II DFU. However, this impact requires at least 2 weeks or more than 6 sessions. For better comparison, further studies with larger clinical groups and extended period are needed.

BIOMICROSCOPY HIGHLIGHTS THE EFFICACY OF SKIN GRAFT ON MICROVASCULAR PARAMETERS IN NON-DIABETIC ULCERS

Objective. Laser Doppler owmetry (LDF), transcutaneous partial pressure of oxygen (pO2) and carbon dioxide (pCO2), and Biomicroscopy (BM) are exams used in daily clinical practice to assess capillary and microvascular functionality. Skin graft (SG) is a well-established intervention for the treatment of chronic lower leg ulcers. The sequence of improvements at the microvascular and macrovascular level, letting to a successful outcome after SG, is not yet been determined. This observation aims to determine which parameters of capillary functionality could show how SG takes to a positive outcome. Methods. In this trial, cutaneous perfusion, district microcirculatory reserve, and variation of cutaneous perfusion induced by the postural vasoconstriction reex (VAR) were measured with LDF as the number and diameter of capillary loops at 1 cm, 2 cm, and 4 cm from the big toe nailfold and the ulcer edge. Cutaneous gas exchanges were detected through pO2 and pCO2, and capillary density and average diameter loops were recorded with BM. Because of the exploratory nature of this study, consecutive patients' afferent to our structure receiving SG for the treatment of non-diabetic chronic non-relapsing ulcers on the lower limb, were assessed before and 5 days after SG. All measures were collected by the same operator and SG was performed in a standardized manner. Paired non-parametric statistical tests were performed to compare basal with after SG measurements. Results. All 13 patients observed had a clinically successful outcome after SG in terms of pain reduction, absence of SG complications, and absence of secretion. The median number of capillary loops changed at the different evaluation points (e.g. from 19 vs 21 (P=.004) at the big toe nailfold and 16 vs. 22 (P&lt;.001) at 2 cm from the ulcer edge). The median diameter of capillary loops changed at the different evaluation points (e.g. at the big toe nailfold decreased from 24mm to 19mm (P=.004) and from 16mm to 22mm (P=.031) at 2 cm from the ulcer). The median values of pO2 increased from 10 mmHg to 36 mmHg (P=.005) on supine and from 28 mmHg to 3 mmHg (P=.006) at the dependent lower limb None of the LDF measures, or pCO2.Conclusion.In this exploratory evaluation, BM measurements reveal, for the rst time, a successful outcome after SG for the treatment of chronic lower limb skin ulcers, especially on the big toe nailfold, 1 and 2 cm from the ulcer. The improvement observed at the capillary level seems parallel with the improvement of tissue oxygenation

A Volunteer Crossover Feasibility Study to Compare Standard Oxygen Cannula Used at High-Flow to Proprietary High-Flow Humidified Nasal Oxygen Systems.

Supplemental oxygen is routinely administered topatients prior to and during induction of general anesthesia and sedation. This increases the fraction of oxygen in the lungs,increases oxygen delivery, and increases the time to oxygen desaturation. Proprietary Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) systems, whichdeliver warmed and humidified oxygen, have been extensivelyresearched in the perioperative and critical care setting and have beenshown to significantly prolong time to desaturation and as a means of ventilatory support. The use of traditionalnasal oxygen cannula used at maximum flow ratesis currently used in short bursts as it is poorly tolerated. There is however a dearth of data examining the use of this technique. We hypothesized that traditionalnasal oxygen cannulae used at maximum flow rates can deliver oxygen aseffectively as THRIVE in this setting. We designed a crossover volunteer feasibility study. The participants were 10 healthy anesthetists. We compared the two methods of oxygen delivery by measuring transcutaneous oxygen measurement andpharyngeal oxygen concentration. Comfort and noise levels were recorded. The aforementioned parameters werecompared between the two groups. We observed that a standard oxygencannula used athigh flows delivers comparable oxygen delivery and tissue oxygenationperformanceto proprietary THRIVE systems. However, they are lesscomfortable andmake more noise. To the authors' knowledge this study is the first to study the oxygen delivery of traditionalnasal oxygen cannula used at maximum flow rates and make comparisons to the well-studied THRIVE technique. While similar transcutaneous partial pressure of oxygen and pharyngeal gas concentrations were observed with both techniques, the standard cannulae were deemed to be a lot less comfortable than THRIVE and made a lot more noise which likely limit the utility of this technique outside of short bursts. In this study, a standard nasal oxygen cannula used at highflows achieved similar oxygen delivery to THRIVE at the expense of poorcomfort and increased noise.

Comparison of Antera 3D® and TcPO2 for Evaluation of Blood Flow in Skin.

There is a need for quick skin blood flow tests that can be performed in the wound healing field. Antera 3D® is a compact scanner using multispectral imaging. It can perform quick assessment of skin conditions. The purpose of the present study was to investigate the ability of the Antera 3D® to assess skin blood flow in comparison with transcutaneous partial pressure of oxygen (TcPO2) measurements. This study was conducted on 13 patients with a history of lower extremity ulcers. Measurements of hemoglobin average level (hereafter, Hb score) measured by Antera 3D® and TcPO2 measured by a transcutaneous blood gas monitor were obtained at the same sites on the dorsal foot and lower leg. Differences in Hb score and TcPO2 were analyzed by t-test for each measurement site and for the presence of peripheral arterial disease (PAD). The correlation between TcPO2 and Hb score was analyzed by Pearson's correlation coefficient. Twenty-four limbs were tested. Hb score was higher (P < 0.001) and TcPO2 was lower (P = 0.056) in the dorsal foot compared to the lower leg. In the dorsal foot, Hb score was higher (P = 0.023) and TcPO2 was lower (P = 0.046) in patients with PAD compared to those without PAD. A significant negative correlation (r = -0.68; 95% confidence interval -0.85 to -0.38, P < 0.001) between TcPO2 and Hb score was observed in the dorsal foot. The negative correlation between TcPO2 and Hb score may reflect compensatory peripheral vasodilation due to occlusion or stenosis of central arteries. This study showed that Hb score measured by Antera 3D® may be related to skin blood flow.

EFEITO DO MÉTODO DE APRENDIZAGEM BASEADA EM PROBLEMAS EM ELETROENCEFALOGRAMAS E PERFUSÃO SANGUÍNEA MICROCIRCULATÓRIA DE ESTUDANTES NO ENSINO DE FISIOLOGIA DO ESPORTE

ABSTRACT Introduction Applying the problem-based learning (PBL) method to the teaching of sports physiology. Objective This study explored the mechanism of the PBL method to improve the interest and learning effectiveness of students. Methods Twenty male students at the Physical Education College of Hubei Minzu University were randomly divided into a PBL group (10) and a traditional teaching method group (TTM). During the test, the subjects in the TTM group sat quietly listening to the experienced teacher, while the subjects in PBL group sat quietly and participated in a 20-minute group discussion under the guidance of the experienced teacher. Transcutaneous partial pressure of oxygen (TcPO2), microcirculatory blood perfusion (MBP), and alpha- and beta-band power were monitored at the beginning of and during the test. Results The mean of the PBL-group quiz score was significantly higher than that of the TTM group. In the PBL group, the alpha power of the students decreased statistically in the F3, T3, P3, and O1 channels and the beta power of the students increased statistically in the F7, F3, T3, C3, P3, and O1 as compared to the baseline values. Conclusion PBL can be an effective learning mechanism, since the students are actively engaged in the teaching of sports physiology. Level of Evidence I; Therapeutic studies - Investigating treatment results.

Non-invasive high frequency oscillatory ventilation inhibiting respiratory motion in healthy volunteers

Precision radiotherapy needs to manage organ movements to prevent critical organ injury. The purpose of this study is to examine the feasibility of motion control of the lung by suppressing respiratory motion. The non-invasive high frequency oscillatory ventilation (NIHFOV) is a technique commonly used in the protection of lung for patients with acute lung disease. By using a very high respiratory frequency and a low tidal volume, NIHFOV allows gas exchange, maintains a constant mean airway pressure and minimizes the respiratory movements. We tested healthy volunteers NIHFOV to explore the optimal operational parameter setting and the best possible motion suppression achievable. This study was conducted with the approval of Institutional Review Boards of the Wuwei Cancer hospital (approval number: 2021-39) and carried out in accordance with Declaration of Helsinki. The study comprises two parts. Twenty three healthy volunteers participated in the first part of the study. They had 7 sessions of training with the NIHFOV. The duration of uninterrupted, continuous breathing under the NIHFOV and the optimal operational machine settings were defined. Eight healthy volunteers took part in the second part of the study and underwent 4-dimensional CT (4DCT) scanning with and without NIHFOV. Their respiratory waveform under free breathing (FB) and NIHFOV were recorded. The maximum range of motion of the diaphragm from the two scannings was compared, and the variation of bilateral lung volume was obtained to evaluate the impact of NIHFOV technique on lung volume. The following data were collected: comfort score, transcutaneous partial pressure of oxygen (PtcO2), transcutaneous partial pressure of carbon dioxide (PtcCO2), and pulse rate. Data with and without NIHFOV were compared to evaluate its safety, physiological impacts and effect of lung movement suppression. All the volunteers completed the training sessions eventlessly, demonstrating a good tolerability of the procedure. The median NIHFOV-on time was 32 min (22–45 min), and the maximum range of motion in the cephalic-caudal direction was significantly reduced on NIHFOV compared with FB (1.8 ± 0.8 cm vs 0.3 ± 0.1 cm, t = − 3.650, P = 0.003); the median range of motion was only 0.3 ± 0.1 cm on NIHFOV with a good reproducibility. The variation coefficient under NIHFOV of the right lung volume was 2.4% and the left lung volume was 9.2%. The PtcO2 and PtcCO2 were constantly monitored during NIHFOV. The medium PtcCO2 under NIHFOV increased lightly by 4.1 mmHg (interquartile range [IQR], 4–6 mmHg) compared with FB (t = 17.676, P < 0.001). No hypercapnia was found, PtcO2 increased significantly in all volunteers during NIHFOV (t = 25.453, P < 0.001). There was no significant difference in pulse rate between the two data sets (t = 1.257, P = 0.233). NIHFOV is easy to master in healthy volunteers to minimize respiratory movement with good tolerability and reproducibility. It is a feasible approach for lung motion control and could potentially be applied in accurate radiotherapy including carbon-ion radiotherapy through suppression of respiratory movement.

Impact of compression on velocity of venous and arterial main blood flow and cutaneous microcirculation of the lower extremity

Objective. To study the impact of compression on velocity of venous and arterial main blood flow of the lower extremity, as well as cutaneous microcirculation in the back part of the foot in healthy individuals and patients with decompensated forms of varicose disease and postthrombophlebitis syndrome.&#x0D; Materials and methods. In the investigation 56 individuals took part and divided into three groups: Group I – 20 healthy persons; Group II – 15 patients with varicose disease in decompensated stage; Group III– 21 patients with decompensated stage of postthrombophlebitis syndrome.&#x0D; In all participants of the investigation the index of ankle–brachial pressure, deep–femoro–popliteal index, the regional perfusion index, transcutaneous partial pressure of oxygen and partial pressure of carbon dioxide, the arterial blood flow velocity in femoral artery and of venous blood flow distally from sapheno–femoral junction were measured before and after application of elastic medical knitwear of various Class of compression or the cuff pressure.&#x0D; Results. In the Class III compression in patients of Group III the transcutaneously registered indices crossing have occurred between partial pressure of oxygen and carbon dioxide, accompanied by domination of the carbon dioxide partial pressure over the oxygen partial pressure while further enhancement of the compression Class. In patients of Group II this tendency was observed while application of Class IV compression only. At the investigation beginning the values of partial pressure of carbon dioxide registered were higher in the Group III patients, than in the patients of Group II (p=0.0001).&#x0D; Conclusion. While application of the Class III compression the velocity of the hip venous blood flow, comparing with its initial values, have lowered at average by 78% in patients of Group II and at average in 7.4 times in the patients of |Group III (p=0.0001). It is affordable in patients, suffering decompensated postthrombophlebitic syndrome, to apply the elastic compression of Classes I–II, while in those, having varicose disease in decompensated stage, – the elastic compression of Classes III and iV as well.