Transcutaneous Oximetry Research Articles

Evaluation of an effect of profundoplasty on peripheral tissue perfusion in patients with peripheral arterial disease using transcutaneous oximetry

Evaluation of an effect of profundoplasty on peripheral tissue perfusion in patients with peripheral arterial disease using transcutaneous oximetry

The role of transcutaneous oximetry at exercise test in the diagnosis of proximal claudication

The role of transcutaneous oximetry at exercise test in the diagnosis of proximal claudication

Exercise transcutaneous oximetry in functional popliteal artery entrapment syndrome diagnosis.

Functional poplitealartery entrapment syndrome is a subtype of poplitealartery entrapment syndrome (PAES) without vascular disease or musculotendinous anomaly behind the knee. Symptoms are induced by popliteal artery extrinsic compression, leading to calf pain during lower limbs exercise. Non-invasive tests are still required to improve the diagnostic management of functional PAES. Exercise transcutaneous oxygen pressure (Ex-tcpO2) is of interest to provide objective arguments for the presence of regional blood flow impairment. The aim of the study was to analyze whether Ex-tcpO2 could serve as a non-invasive technique for detecting ischemia resulting from PAES. Patients with suspected PAES were recruited between 2017 and 2020. The diagnosis was confirmed or rejected, according to the surgical decision based on our diagnosis management involving a multidisciplinary team. Each patient underwent Ex-tcpO2 with specific maneuvers. The decrease from rest of oxygen pressure (DROP) index served for the interpretation of exercise results. Sixty-five legs with suspected PAES were recruited. Diagnosis was confirmed in 34 (52.3%) and rejected in 32 (47.7%). The average DROP values found in confirmed and rejected group at left leg were -21.6 ± 15.4mmHg and -10.9 ± 11.1mmHg, respectively (p for Mann-Whitney 0.004), and -15.8 ± 11mmHg and -11.1 ± 7.5mmHg, respectively, at right leg (p = 0.088). Ex-tcpO2 sensitivity and specificity were 52.9% and 78.1%, respectively. Ex-tcpO2 is an original non-invasive investigation for patients with claudication of doubtful arterial origin. The sensitivity and specificity are 52.9% and 78.1% in functional PAES diagnosis using 15mmHg as threshold to detect ischemia during tiptoeing elevations.

The phenomenon of drug-coating embolism during lower extremity endovascular interventions with paclitaxel-coated balloon.

There is a risk of distal embolization lower extremity endovascular interventions. Possibly a drug-coating embolism caused by coating detachment from intravascular devices. This review focuses on providing updated information on distal embolism in endovascular revascularization of lower extremity arteries, including the use of drug-coated balloons. Drug-coating embolism is a special case of distal embolization during recanalization of the arteries of the lower extremities. Preclinical studies have demonstrated embolization of drug-coated balloons during angioplasty of lower extremity arteries. However, the clinical role of drug-coating embolism is not completely clear. A 2020 meta-analysis found an increased risk of major lower extremity amputation after drug-coated balloon angioplasty in patients with critical limb ischemia. But long-term research is emerging to support the safety of using these devices. Perhaps a more thorough assessment of the quality of life and the degree of compensation of lower limb ischemia with an intraoperative assessment of the frequency of peripheral embolizations using ultrasound emboli detection, as well as microcirculation with transcutaneous oximetry and laser Doppler flowmetry of the operated lower limb will allow a more detailed study of the phenomenon of drug-coating embolism and its impact on long-term clinical outcomes. According to the results of preclinical studies, the use of paclitaxel-coated balloons leads to an increase in the concentration of paclitaxel in distal skeletal muscles. However, paclitaxel concentration in skeletal muscle was significantly higher in first-generation DCBs. The non-target effects of drug-coating balloon are not fully understood and require further study. Understanding the phenomenon of drug-coating embolism can help physicians to better assess the patient risk and to minimize complications.

Effects of Oxygen Therapy on Patients with a Chronic Wound: A Systematic Review and Meta-analysis.

To synthesize the effects of oxygen-based therapy on patients with a chronic wound. The authors searched PubMed, EMBASE, and Cochrane Central Register of Controlled Trials for relevant randomized controlled trials from database inception. Investigators measured risk of bias using the Cochrane Collaboration's Risk of Bias tool. The included randomized controlled trials focused on the effects (short- or long-term wound healing, amputation rate, percentage of reduction in ulcer size, and poststudy transcutaneous oxygen measurement [TcPO2]) of oxygen-based therapy (including hyperbaric oxygen therapy, topical oxygen therapy, and continuous diffusion of oxygen) on patients with a chronic wound. Researchers extracted information regarding participant characteristics and primary and secondary outcomes from the included studies. Pooled effects of 31 included studies showed that patients treated with oxygen had better short-term wound healing (risk ratio [RR], 1.544; 95% CI, 1.199 to 1.987), a higher percentage reduction in the ulcer area (standardized mean difference [SMD], 0.999; 95% CI, 0.439 to 1. 599), lower amputation rates (RR, 0.529; 95% CI, 0.325 to 0.862), shorter wound healing time (SMD, -0.705; 95% CI, -0.908 to -0.501), and higher poststudy TcPO2 (SMD, 2.128; 95% CI, 0.978 to 3.278) than those in the control group. For long-term wound healing, there was no statistically significant difference (RR, 1.227; 95% CI, 0.976 to 1.542). Oxygen-based therapy improves short-term parameters of wound healing in patients with chronic wounds.

Transcutaneous oximetry values in chronic ulcer patients during Hyperbaric treatment at 1.4 ATA compared to 2 ATA

Chronic wounds have a significant impact on a patient’s quality of life. Different pathologies, such as poor blood supply and tissue breakdown, may lead to inadequate oxygenation of the wound. Hyperbaric oxygen (HBO2 ) is a widely used treatment for an increasing number of medical practices. A new so-called “hyperbaric treatment” trend has emerged. The use of low-pressure, soft-sided, or inflatable chambers represents a growing trend in hyperbaric medicine. Used in professional settings as well as directly marketed to individuals for home use, they are promoted as equivalent to clinical hyperbaric treatments provided in medical centers. However, these chambers are pressurized to 1.3 atmospheres absolute (ATA) on either air or with an oxygen concentrator, both generate oxygen partial pressures well below those used in approved hyperbaric centers for UHMS-approved indications. A total of 130 consecutive patients with chronic ulcers where tested. TcPO2 was measured near the ulcer area while the patient was breathing 100% O2 at 1.4 ATA for five and 10 minutes. The average TcPO2 at 1.4 ATA after 10 minutes of O2 breathing was 161 mmHg (1-601 mmHg, standard deviation 137.91), compared to 333 mmHg in 2 ATA (1-914±232.56), p < 0.001). Each electrode tested was also statistically significant, both after five minutes of O2 breathing and after 10 minutes. We have not found evidence supporting the claim that 1.4 ATA treatment can benefit a chronic ulcer patient. The field of HBO2 is constantly evolving. We have discovered new ways to treat previously incurable ailments. Nevertheless, it is important to note that new horizons must be examined scientifically, supported by evidence-based data. The actual effect of 1.4 ATA on many ailments is yet to be determined.

Transcutaneous oximetry of angiosomes of maxillary and facial arteries

Aim. To qualitatively predict and control the quality of periodontal diseases treatment, to determine changes in the transcutaneous pressure of oxygen and carbon dioxide in angiosomes of maxillary and facial arteries in healthy adults. Materials and methods. 17 healthy people participated in this study. There were 10 (58 %) men aged 24 (22–27), weight 66 (62–80) kg and height 175 (169–182) cm and 7 (42 %) women, whose average age was 23 (20–26) years old, weight 58 (47–72) kg, height 165 (160–178) cm. Results. The highest values of tissue perfusion with oxygen were observed in the angiosomes of the upper jaw compared to the angiosomes of the lower jaw, where this indicator ranged from 105 to 153 mm Hg. On the lower jaw, the maximum value of the regional perfusion index (RPI) of 1.70 ± 0.04 was observed at the point of measurement where a. mentalis exits through the homonymous chin orifice, anastomosing with the branches of a. facialis. The highest values of tissue perfusion with carbon dioxide were observed in angiosomes of the lower jaw (28–36 mm Hg). In general, non-invasive measurements of oxygen and carbon dioxide pressure in tissues allow more accurate and direct visualization and control of microcirculation in the tissues of the corresponding angiosomes. Conclusions. The index of regional perfusion on the upper jaw is normally in the range of 2.2 to 2.6 (р < 0.0001). In the angiosome of the lower jaw, the RPI value is within 1.3–1.7, respectively (p < 0.0001). The tension of carbon dioxide in the tissues of the upper and lower jaw averages 31–34 mm Hg (р < 0.05), reaches its maximum in the zones of the lowest oxygen perfusion.

Use of consecutive transcutaneous oxygen measurement when assessing the need for revascularization and association with the outcomes of ischemic diabetic ulcers.

This study compared the ankle-brachial index (ABI) with transcutaneous oxygen pressure (TcPO2 ) in assessing peripheral vascular disease (PVD) prevalence in 100 diabetic foot ulcer (DFU) patients. Patients were categorized into vascular or nonvascular reconstruction groups and underwent both ABI and TcPO2 measurements four times over 6 months. Predictive validity for PVD diagnosis was analysed using the area under the receiver-operating characteristic curve (AUC). The study found TcPO2 to be a superior predictor of PVD than ABI. Among the DFU patients, 51 with abnormal TcPO2 values underwent vascular reconstruction. Only TcPO2 values showed significant pretreatment differences between the groups and increased post-reconstruction. These values declined over a 6-month follow-up, whereas ABI values rose. For those with end-stage renal disease (ESRD), TcPO2 values saw a sharp decrease within 3 months. Pre-reconstruction TcPO2 was notably lower in amputation patients versus limb salvage surgery patients. In conclusion, TcPO2 is more effective than ABI for evaluating ischemic limb perfusion and revascularization necessity. It should be prioritized as the primary follow-up tool, especially for ESRD patients.

Von Willebrand factor hyperactivity affects the outcome of lower limb revascularization in subjects with type 2 diabetes mellitus complicated by diabetic foot vasculopathy: An observational pilot study

Aim of this study is to evaluate any differences in VWF antigen, VWF activity and ADAMTS-13 activity before and after successful and non-successful Percutaneous Transluminal Angioplasty (PTA) in subjects with type 2 diabetes (T2DM) complicated by Chronic limb-threatening ischemia (CLTI) in diabetic foot vasculopathy. MethodsIn this prospective observational pilot study, we enrolled 35 T2DM subjects who underwent lower limb PTA. Transcutaneous oximetry was performed in all patients before and 6 weeks after PTA. The change in oxygen partial pressure (TcpO2) before and after PTA was expressed as TcpO2-delta (ΔTcpO2). VWF antigen, VWF activity and ADAMTS-13 activity were measured before and 6 weeks after PTA; changes were expressed as delta and ratio from baseline. ResultsSubjects with ∆TcpO2 < 15 mmHg presented higher ΔVWF activity (p = 0.050) and lower ADAMTS-13 activity ratio (p = 0.080). Subjects with ∆TcpO2 < 30 mmHg showed lower ADAMTS-13 activity Δ and ratio (p = 0.028). ConclusionsVWF antigen levels and VWF activity may potentially affect PTA outcome. Higher levels of VWF could derive from VWF release as consequence of PTA-induced mechanical endothelial damage and/or oxidative stress-induced modifications of VWF structure with impairment of VWF-ADAMTS13 interactions.

Does the advantage of transcutaneous oximetry measurements in diabetic foot ulcer apply equally to free flap reconstruction?

Type 2 diabetes mellitus (T2DM), which is distinguished by increased glucose levels in the bloodstream, is a metabolic disease with a rapidly increasing incidence worldwide. Nevertheless, the etiology and characteristics of the mechanism of T2DM remain unclear. Recently, abundant evidence has indicated that the intestinal microbiota is crucially involved in the initiation and progression of T2DM. The gut microbiome, the largest microecosystem, engages in material and energy metabolism in the human body. In this review, we concentrated on the correlation between the gut flora and T2DM. Meanwhile, we summarized the pathogenesis involving the intestinal flora in T2DM, as well as therapeutic approaches aimed at modulating the gut microbiota for the management of T2DM. Through the analysis presented here, we draw attention to further exploration of these research directions.

Test-retest Reliability and Minimal Detectable Change in Exercise Oximetry in Claudicants

Exercise transcutaneous oxygen pressure measurement (Exercise-TcPO2) can be used to diagnose Lower Extremity Artery Disease (LEAD) and allows the quantification of limb ischemia during exercise on treadmill. Exercise-TcPO2 test-retest reliability in patients with LEAD and severe walking impairment is unknown. The aim of this study was to evaluate the test-retest reliability, standard error of measurement (SEM), and Minimal Detectable Change (MDC) of exercise-TcPO2 in patients with claudication. Data were collected from patients that performed 2 treadmill tests within a 1-month interval. Delta from Rest of Oxygen Pressure (DROP) values were measured at both buttocks (proximal) and both calves (distal). Test-retest reproducibility was assessed by recording transcutaneous oximetry measurements twice and expressed as SEM and intra-class correlation coefficients. MDC was calculated using the formula MDC = SEM x 1.96 x √2. Twenty eight LEAD patients (61±9years old) were included. Intra-class correlation coefficients were 0.66 [0.50, 0.79] and 0.65 [0.49, 0.79] for the proximal and distal levels, respectively. The SEM of DROP at the proximal and distal levels were 7 [6, 9] mm Hg and 9 [8, 11] mm Hg, respectively. The SEM for all (proximal and distal) DROP values was 8 [7, 10] mm Hg and the MDC of DROP was 23mm Hg. Exercise-TcPO2 with measurement of DROP values has a moderate test-retest reliability in LEAD patients with a maximal walking distance ≤ 300m. For an individual, an improvement or deterioration in DROP of ≥ 23mm Hg after an intervention would be required to be 95% confident that the change is significant. It should be considered in evaluating the impact of treatment in patients with claudication.

Autologous Bone Marrow Stem Cells in Patients With Critical Limb Ischaemia not Eligible for Revascularization: A Single Centre Experience.

We evaluated the use of autologus bone marrow stem cells transplantation in patients with critical limb ischaemia (CLI) not eligible for revascularization. Eighty consecutive patients candidate to amputation were enrolled in a single-centre retrospective study. The primary endpoint was defined as the amputation-free rate from stem cells transplantation. Secondary endpoints were the evaluation of transcutaneous oximetry and its predictive potential for probability of amputation and the evaluation of rest pain. Ankle brachial index, transcutaneous oxygen (TcpO2) and radiological imaging were performed at the enrolment and during the follow-up times. All patients were treated with auto transplant of bone marrow stem cells. Two patients died due to acute renal and acute respiratory failures. 19 patients were amputated from the thigh or leg. In total, 59 of 80 patients intended to thigh amputation saved the limb, preserving the plantar support. TcpO2 was found a predictive metric with an AUC equal to .763, and a threshold for a risk of amputation of 10% and 5% at the values ≤22.7 and ≤26.9mmHg, respectively. Auto transplant of bone marrow stem cells seems to be a safe and an efficient option for CLI not eligible to revascularizzation.

Evaluation of a New Telemedicine System for Early Detection of Cardiac Instability in Patients With Chronic Heart Failure: Real-Life Out-of-Hospital Study.

For a decade, despite results from many studies, telemedicine systems have suffered from a lack of recommendations for chronic heart failure (CHF) care because of variable study results. Another limitation is the hospital-based architecture of most telemedicine systems. Some systems use an algorithm based on daily weight, transcutaneous oxygen measurement, and heart rate to detect and treat acute heart failure (AHF) in patients with CHF as early on as possible. The aim of this study is to determine the efficacy of a telemonitoring system in detecting clinical destabilization in real-life settings (out-of-hospital management) without generating too many false positive alerts. All patients self-monitoring at home using the system after a congestive AHF event treated at a cardiology clinic in France between March 2020 and March 2021 with at least 75% compliance on daily measurements were included retrospectively. New-onset AHF was defined by the presence of at least 1 of the following criteria: transcutaneous oxygen saturation loss, defined as a transcutaneous oxygen measurement under 90%; rise of cardiac frequency above 110 beats per minute; weight gain of at least 2 kg; and symptoms of congestive AHF, described over the phone. An AHF alert was generated when the criteria reached our definition of new-onset acute congestive heart failure (HF). A total of 111 consecutive patients (n=70 men) with a median age of 76.60 (IQR 69.5-83.4) years receiving the telemonitoring system were included. Thirty-nine patients (35.1%) reached the HF warning level, and 28 patients (25%) had confirmed HF destabilization during follow-up. No patient had AHF without being detected by the telemonitoring system. Among incorrect AHF alerts (n=11), 5 patients (45%) had taken inaccurate measurements, 3 patients (27%) had supraventricular arrhythmia, 1 patient (9%) had a pulmonary bacterial infection, and 1 patient (9%) contracted COVID-19. A weight gain of at least 2 kg within 4 days was significantly associated with a correct AHF alert (P=.004), and a heart rate of more than 110 beats per minute was more significantly associated with an incorrect AHF alert (P=.007). This single-center study highlighted the efficacy of the telemedicine system in detecting and quickly treating cardiac instability complicating the course of CHF by detecting new-onset AHF as well as supraventricular arrhythmia, thus helping cardiologists provide better follow-up to ambulatory patients.

Diabetic Foot Ulcer Imaging: An Overview and Future Directions.

Diabetic foot ulcers (DFUs) affect one in every three people with diabetes. Imaging plays a vital role in objectively complementing the gold-standard visual yet subjective clinical assessments of DFUs during the wound treatment process. Herein, an overview of the various imaging techniques used to image DFUs is summarized. Conventional imaging modalities (e.g., computed tomography, magnetic resonance imaging, positron emission tomography, single-photon emitted computed tomography, and ultrasound) are used to diagnose infections, impact on the bones, foot deformities, and blood flow in patients with DFUs. Transcutaneous oximetry is a gold standard to assess perfusion in DFU cases with vascular issues. For a wound to heal, an adequate oxygen supply is needed to facilitate reparative processes. Several optical imaging modalities can assess tissue oxygenation changes in and around the wounds apart from perfusion measurements. These include hyperspectral imaging, multispectral imaging, diffuse reflectance spectroscopy, near-infrared (NIR) spectroscopy, laser Doppler flowmetry or imaging, and spatial frequency domain imaging. While perfusion measurements are dynamically monitored at point locations, tissue oxygenation measurements are static two-dimensional spatial maps. Recently, we developed a spatio-temporal NIR-based tissue oxygenation imaging approach to map for the extent of asynchrony in the oxygenation flow patterns in and around DFUs. Researchers also measure other parameters such as thermal maps, bacterial infections (from fluorescence maps), pH, collagen, and trans-epidermal water loss to assess DFUs. A future direction for DFU imaging would ideally be a low-cost, portable, multi-modal imaging platform that can provide a visual and physiological assessment of wounds for comprehensive wound care intervention and management.

METABOLIC (TCPO2) AND HEMODYNAMIC DISCORDANCE IN PERIPHERAL VASCULAR EVALUATION OF POSTOPERATIVE STUMP NECROSIS. ABOUT TWO CASES AND LITERATURE REVIEW

Objective: Amputation levels are discussed based on hemodynamic approach. Transcutaneous oximetry (TcPO2) is a metabolic test of the local perfusion of peripheral tissues. we report two cases of discordance between hemodynamic and metabolic tests in the evaluation of the level of amputation on stump necrosis. Design and method: study of two cases of amputation level decision using ABI, arterial doppler ultrasound and TcPO2 Results: 1st case: patient A D 52 years old, type 2 diabetic for 11 years, admitted 12 days after amputation of the left forefoot following a complication of the infectious and neuropathic diabetic foot. The clinical examination found an infected necrosis of the amputation stump, the ABI is at 1.22. The arterial Doppler ultrasound objective an atheromatous overload and a good arterial flow. The TcPO2 is 69 mmHg next to the stump, contrasting with a TcPO2 of 27 mmHg on the right. The decision was a necrectomy associated with an antibiotic therapy adapted to the antibiogram. The evolution was favorable. 2nd case: patient S B 71 years old, hypertensive for 20 years, paraplegic for 20 years following a spinal trauma. Hospitalized for management of acute ischemia of the lower limbs on paroxysmal AF. Doppler ultrasound performed in the context of the emergency was in favor of the total occlusion of the regular poplar and leg arteries. Rejected from revascularization, evolution under anticoagulant was marked by the appearance of dry gangrene of both feet. The preoperative evaluation was in favor of a TcPO2 of 41 mmHg on the left and 75 mmHg on the right. An amputation of the two forefeet was performed. The postoperative evolution was characterized by a necrosis of the left stump requiring a complementary gesture with good consequences. Conclusions: The two cases clearly demonstrate the discrepancy between the classic evaluation (anatomical and hemodynamic) and the metabolic evaluation (TcPO2) The TcPO2 provides valuable assistance in deciding the level of amputation regardless of the diabetic, hypertensive, elderly patient profile….and regardless of the vascular profile; normal, PAD, post acute ischemia The TcPO2 is essential before each amputation procedure independently of the hemodynamic evaluation.

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.

Improving the Clinical Interpretation of Transcutaneous Carbon Dioxide and Oxygen Measurements in the Neonatal Intensive Care Unit

Introduction: Transcutaneous blood gas monitoring allows for continuous non-invasive evaluation of carbon dioxide and oxygen levels. Its use is limited as its accuracy is dependent on several factors. We aimed to identify the most influential factors to increase usability and aid in the interpretation of transcutaneous blood gas monitoring. Methods: In this retrospective cohort study, transcutaneous blood gas measurements were paired to arterial blood gas withdrawals in neonates admitted to the neonatal intensive care unit. The effects of patient-related, microcirculatory, macrocirculatory, respiratory, and sensor-related factors on the difference between transcutaneously and arterially measured carbon dioxide and oxygen values (ΔPCO₂ and ΔPO₂) were evaluated using marginal models. Results: A total of 1,578 measurement pairs from 204 infants with a median [interquartile range] gestational age of 27³/₇ [26¹/₇–31³/₇] weeks were included. ΔPCO₂ was significantly associated with the postnatal age, arterial systolic blood pressure, body temperature, arterial partial pressure of oxygen (PaO₂), and sensor temperature. ΔPO₂ was, with the exception of PaO₂, additionally associated with gestational age, birth weight Z-score, heating power, arterial partial pressure of carbon dioxide, and interactions between sepsis and body temperature and sepsis and the fraction of inspired oxygen. Conclusion: The reliability of transcutaneous blood gas measurements is affected by several clinical factors. Caution is recommended when interpreting transcutaneous blood gas values with an increasing postnatal age due to skin maturation, lower arterial systolic blood pressures, and for transcutaneously measured oxygen values in the case of critical illness.

Using of Transcutaneous Oximetry (tcpO2) as Indicated Test at Hyperbaric and Wound Care

Using of Transcutaneous Oximetry (tcpO2) as Indicated Test at Hyperbaric and Wound Care

Biomarkers of Neutrophil Activation in Patients with Symptomatic Chronic Peripheral Artery Disease Predict Worse Cardiovascular Outcome

Neutrophils play a role in cardiovascular (CV) disease. However, relatively scant evidence exists in the setting of peripheral artery disease (PAD). The aims of this study were to measure biomarkers of neutrophil activation in patients with symptomatic chronic PAD compared with healthy controls, to assess their association with PAD severity, and to evaluate their prognostic value in patients with PAD. The following circulating markers of neutrophil degranulation were tested: polymorphonuclear neutrophil (PMN) elastase, neutrophil gelatinase-associated lipocalin (NGAL), and myeloperoxidase (MPO). Neutrophil extracellular traps (NETs) were quantified by measuring circulating MPO-DNA complexes. Patients with PAD underwent a comprehensive series of vascular tests. The occurrence of 6-month major adverse CV (MACE) and limb events (MALE) was assessed. Overall, 110 participants were included, 66 of which had PAD. After adjustment for conventional CV risk factors, PMN-elastase (adjusted odds ratio [OR]: 1.008; 95% confidence interval [CI]: 1.002-1.015; p = 0.006), NGAL (adjusted OR: 1.045; 95%CI: 1.024-1.066; p < 0.001), and MPO (adjusted OR: 1.013; 95%CI: 1.001-1.024; p = 0.028) were significantly associated with PAD presence. PMN-elastase (adjusted hazard ratio [HR]: 1.010; 95%CI: 1.000-1.020; p = 0.040) and MPO (adjusted HR: 1.027; 95%CI: 1.004-1.051; p = 0.019) were predictive of 6-month MACE and/or MALE. MPO displayed fair prognostic performance on receiver operating characteristic (ROC) curve analyses, with an area under the curve (AUC) of 0.74 (95%CI: 0.56-0.91) and a sensitivity and specificity of 0.80 and 0.65, respectively, for a cut-off of 108.37 ng/mL. MPO-DNA showed a weak inverse correlation with transcutaneous oximetry (TcPO2) on proximal foot (adjusted ρ -0.287; p = 0.032). In conclusion, in patients with symptomatic chronic PAD, enhanced neutrophil activity may be associated with an increased risk of acute CV events, rather than correlate with disease severity. Further research is needed to clarify the role of neutrophils in PAD natural history.

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.