External Mechanical Compression Research Articles

Evaluation of a Novel Mechanical Compression Device.

Venous thromboembolism (VTE) is a leading preventable cause of death in hospitalized patients. Current intermittent pneumatic compression (IPC) devices used to provide external mechanical compression for VTE prevention are associated with a multitude of clinical challenges that often result in subtherapeutic use. A comparative study was conducted of the real-world clinical use of a novel mechanical compression device (MCD) and a current IPC device. The purpose of this quality improvement project was to compare use of the novel MCD and the standard IPC device on three clinical inpatient hospital units. Comparisons were based on the following patient outcome measures: evaluation of wear time, adherence to optimal wear time, evaluation of both patient comfort and device satisfaction, and perceived impact on mobility goals. Nurses' satisfaction with the clinical usability for mobility was also measured. This project used a pre-post design. A convenience sample of 89 surgical patients on the three clinical study units and 63 nursing staff members were recruited for the study. Data were collected using electronic health records, MCD data records, patient surveys, and nursing staff surveys. Data were analyzed using descriptive statistics and independent sample t tests. In the preintervention period, data were collected using the current IPC device. Nursing staff were then trained on use of the MCD. In the postintervention period, the MCDs were used in place of the IPC devices. MCD patients had significantly longer (P ≤ 0.001) wear time (mean, 19.3 hours/day) compared with IPC patients (mean, 12.9 hours/day). MCD patients also reported significantly better sleep (P = 0.04), fewer problems with sweaty legs (P ≤ 0.001), and improved assistance with mobility goals (P ≤ 0.001) than IPC patients. Nursing staff reported significantly improved accuracy of mobility documentation (P ≤ 0.001) with the MCD, but no differences in their perception of patient satisfaction with meeting mobility goals. Use of the MCD device for VTE prophylaxis resulted in actual and perceived improvements from the perspective of both patients and nurses. While these results provide initial data in support of a potentially promising system, more research is needed.

Pressure‐Induced Capacity Recovery and Performance Enhancements in LTO/NMC‐LCO Batteries

AbstractLithium titanate oxide (LTO) batteries are a promising technology, particularly suitable for high‐power applications, owing to their inherent cyclic stability, fast charging capability, and superior safety. However, substantial gas generation and accelerated aging driven by the cathode remain substantial challenges. This study explores the mitigation of these aging mechanisms through the application of external mechanical compression. Continuous pressure of 0.3 MPa applied to pristine cells during cycling reduces capacity loss by 42% compared to unpressurized cells cycled under identical operating conditions. Applying short‐term pressure to aged cells leads to immediate capacity recovery, reclaiming up to 57% of the lost capacity. Subsequent cycling of these aged cells under continuous pressure demonstrates improved capacity retention. In contrast, intermittently applied transient pressure causes notable capacity fluctuations. This study reveals insights into aging and healing mechanisms influenced by external pressure, benefiting both first‐ and second‐life battery applications. Understanding these mechanisms is vital for enhancing performance and lifetime in battery packs, while the findings also highlight promising opportunities for capacity recovery in reused batteries.

Forensic value of soft tissue detachments from the hyoid bone in death due to strangulation asphyxia.

There are no unequivocal histopathological findings for the diagnosis of fatal asphyxia due to neck compression. From the observation of a series of asphyxiation cases, we noted, during microscopic analysis, a high frequency of "detachment" of soft tissues from the hyoid bone. This specifically refers to the presence of an optical space between the surface of the hyoid bone and soft tissues. We aimed to evaluate the detachment of soft tissues from the hyoid bone as specific histological evidence of death due to strangulation asphyxia. Ten blocks were taken from deaths due to external mechanical compression of the neck (strangulation asphyxia, group A), 22 blocks were taken from deaths for other causes without trauma to the neck (group B), and 38 blocks were obtained from living subjects that have undergone laryngectomies (group C). The presence/absence of detachments were compared between the 3 groups (A, B and C) using Fisher's exact test. The detachment of soft tissues from the hyoid bone was observed in 5 cases (50%) in group A, 6 cases (27.2%) in group B, and 17 cases (44.3%) in group C. The sensitivity and specificity of the presence of the detachment in group A were 0.5 (95% confidence interval (95% CI): 0.38-0.62) and 0.57 (95% CI: 0.45-0.69), respectively. The comparison between the 3 groups and the presence/absence of soft tissue detachment showed no statistically significant differences between the groups (p = 0.329), clarifying that soft tissue detachment is a nonspecific variable for all 3 situations. Detachment of soft tissues has poor value as a single element to favor the diagnosis of asphyxia due to violent compression of the neck and should be interpreted as an artifactual finding, unrelated to the neck injury or injury vitality.

Maintaining sleep while improving overnight mobility and comfort with a novel lower limb external mechanical compression system

BackgroundVenous thromboembolism is prevalent, associated with a high degree of morbidity and mortality, and largely preventable. External mechanical compression is a standard of care for prevention, but compliance with traditional external mechanical compression devices is low due to patient reported issues with comfort, mobility, usability, noise, and sleep disturbances. The purpose of this study was to compare user-rated comfort, mobility, usability, noise, perceived sleep disturbance, and objective sleep disturbance for a novel external lower limb mechanical compression device as compared to a standard sequential compression device. MethodUsing a 2-day counterbalanced, within-subject repeated-measures design, 16 participants wore two mechanical compression devices, the commonly-used Kendall SCD Express 9525 (SCD) and the novel Recovery Force Movement and Compressions Device (RF-MAC) for 1 night each in their home while sleep was recorded with polysomnography. For each device, participants also completed questionnaires to assess usability, mobility, perceived noise disturbance, and perceived sleep disturbance. ResultsThe novel RF-MAC device was significantly more comfortable and less noisy than the Kendall SCD. There was marginal evidence that participants sleep longer when wearing the RF-MAC compared to the SCD. User-rated usability, perceived sleep disturbance, and other objective sleep disturbance measures did not differ significantly between the two devices. ConclusionPatients and clinicians should consider the impact of external mechanical compression devices on user comfort and sleep to improve patient compliance.

Design, Fabrication and Characterisation of Multi-Parameter Optical Sensors Dedicated to E-Skin Applications

For many years there has been a strong research interest in soft electronics for artificial skin applications. However, one challenge with stretchable devices is the limited availability of high performance, stretchable, electrical conductors and semiconductors that remain stable under strain. Examples of such electronic skin require excessive amounts of wires to address each sensing element-compression force and strain-in a conventional matrix structure. Here, we present a new process for fabricating artificial skin consisting of an optical waveguide architecture, enabling wide ranging sensitivity to external mechanical compression and strain. The manufacturing process allows design of a fully stretchable polydimethylsiloxane elastomer waveguide with embedded gratings, replicated from low cost DVD-Rs. This optical artificial skin allows the detection of compression forces from 0 to 3.8 N with controllable sensitivity. It also permits monitoring of elongation deformations up to 135%. This type of stretchable optical sensor is highly robust, transparent, and presents a large sensing area while limiting the amount of wires connecting to the sensor. Thus, this optical artificial skin presents far superior mechanical properties compared to current electronic skin.

Therapeutic Bronchoscopy in Benign Central Airway Obstruction

Benign central airway obstruction (BCAO) may occur in patients with post-intubation, tracheostomy, tuberculosis and non-tuberculosis infections, tracheal wall abnormalities, endobronchial benign tumors, vascular abnormalities, benign thyroid tumors and external mechanical compression. The management of BCAO is based on the underlying disease and requires multidisciplinary joint decisions from interventional pulmonology, thoracic surgery, radiology and anesthesia. Therapeutic bronchoscopy for the management of BCAO emergencies includes balloon dilation, stents and lasers.

Achieving Noise Reduction With a Novel Lower Limb External Mechanical Compression System

Hospitals are one of the noisiest public environments in the United States, and hospital noise is associated with disrupted sleep. This study provides insights into the noise levels produced by three commonly used medical devices for mechanical deep vein thrombosis prophylaxis: the VenaFlow Elite System, the Kendall SCD Compression System, and the ArjoHuntleigh Flowtron. Noise levels produced were compared with a novel device, the RF Health MAC™ system, which was designed to provide improved comfort and noise reduction. Results suggest that future innovation in mechanical deep vein thrombosis prophylaxis should include efforts to reduce noise during operation.

Effects of Loading and Boundary Conditions on the Performance of Ultrasound Compressional Viscoelastography: A Computational Simulation Study to Guide Experimental Design.

Most biomaterials and tissues are viscoelastic; thus, evaluating viscoelastic properties is important for numerous biomedical applications. Compressional viscoelastography is an ultrasound imaging technique used for measuring the viscoelastic properties of biomaterials and tissues. It analyzes the creep behavior of a material under an external mechanical compression. The aim of this study is to use finite element analysis to investigate how loading conditions (the distribution of the applied compressional pressure on the surface of the sample) and boundary conditions (the fixation method used to stabilize the sample) can affect the measurement accuracy of compressional viscoelastography. The results show that loading and boundary conditions in computational simulations of compressional viscoelastography can severely affect the measurement accuracy of the viscoelastic properties of materials. The measurement can only be accurate if the compressional pressure is exerted on the entire top surface of the sample, as well as if the bottom of the sample is fixed only along the vertical direction. These findings imply that, in an experimental validation study, the phantom design should take into account that the surface area of the pressure plate must be equal to or larger than that of the top surface of the sample, and the sample should be placed directly on the testing platform without any fixation (such as a sample container). The findings indicate that when applying compressional viscoelastography to real tissues in vivo, consideration should be given to the representative loading and boundary conditions. The findings of the present simulation study will provide a reference for experimental phantom designs regarding loading and boundary conditions, as well as guidance towards validating the experimental results of compressional viscoelastography.

Investigating the accuracy of ultrasound viscoelastic creep imaging for measuring the viscoelastic properties of a single-inclusion phantom

Ultrasound viscoelastic creep imaging is a noninvasive technique that has potential to measure the internal spatial distribution of viscoelastic properties of materials, based on inducing the creep response of the material and using a viscoelastic mechanical model to analyze the creep response. Since how viscoelastic creep imaging can be applied to accurately measure the viscoelastic properties of heterogeneous materials is still unclear, the purpose of this study is to use finite element computer simulation to quantitatively investigate the accuracy of compressional viscoelastography (viscoelastic creep imaging using external mechanical compression as the source of excitation) on measuring the viscoelastic properties of a single-inclusion phantom. The study intends to answer a question: can compressional viscoelastography accurately measure the viscoelastic properties of the inclusion as well as the background material within a single-inclusion phantom? Based on the simulation results, compressional viscoelastography could not accurately measure the viscoelastic properties of the inclusion. The measurement of a viscoelastic property (modulus of elasticity or relaxation time constant) of the inclusion is accurate if and only if the difference in that property between the inclusion and background material is very small, less than around 10%. On the other hand, compressional viscoelastography can accurately measure the viscoelastic properties of the background material regardless of the difference in the viscoelastic properties between the inclusion and background material. In a real biological tissue, the mechanical behaviors are much more complicated and unpredictable than those in a single-inclusion phantom like the one used in the present study. Hence, based on the simulation results of the present study, it could be more challenging to apply compressional viscoelastography to accurately measure the viscoelastic properties of a mass or a target tissue within a real biological tissue. The findings of the present study based on compressional viscoelastography may also be applicable to acoustic-radiation-force-based viscoelastic creep imaging. In the future, experiments are needed to justify the simulation results found in the present study.

Comparison of a nonpneumatic device to four currently available intermittent pneumatic compression devices on common femoral blood flow dynamics

ObjectiveThe purpose of the present study was to compare common femoral vein blood flow enhancement during external mechanical compression using the novel, nonpneumatic Recovery Force Health Movement and Compressions (MAC) System (Recovery Force USA, Fishers, Ind), and four currently available intermittent pneumatic compression devices. MethodsThe MAC device was compared with the Kendall SCD 700 (Cardinal Health, Dublin, Ohio), Arjo Huntleigh Flowtron ACS900 (Arjo, Malmö, Sweden), ActiveCare+S.F.T. (Zimmer Biomet, Warsaw, Ind), and Circul8 (Ortho8, Rocklin, Calif). Doppler ultrasound measurements for each device were directly obtained from the right common femoral vein by a registered vascular technologist. The peak flow velocity and the time taken to reach the peak were calculated. For the MAC system only, the subjects were asked to walk a minimum of 500 steps while wearing the system, which was then checked for slippage. Leg size measurements were obtained using the noncontact Sigvaris Legreader XT5 (Vialis Ortopedia, Turin, Italy). The MAC device is not yet commercially available, and the present study was a prequel to clinical studies of venous thromboembolism prevention. ResultsWe recruited a broad range of 20 subjects who varied in age (mean ± standard deviation [SD], 50.5 ± 16.2 years), body mass index (mean ± SD, 26 ± 5.5 kg/m2), gender (male, 25%; female, 75%), and right calf circumference (mean ± SD, 37.2 ± 5.5 cm). The peak flow velocity compared with the baseline measurements was significantly greater for the Recovery Force Health MAC System for three (Kendall SCD 700, P = .02; ActiveCare+S.F.T., P = .003; Circul8, P < .001) of the four comparisons. Although the difference was not significant, the Arjo Huntleigh Flowtron ACS900 (SD, 3.4 cm/s) had more measurement variability in the peak flow velocity compared with baseline than did the MAC System (SD, 1.9 cm/s). The MAC had a significantly (P < .001) faster rise time to peak flow compared with the comparison devices. It was the only device to achieve the target peak flow velocity over baseline of at least three times in every body mass index group. Finally, the MAC System met the goal of <2.5 cm of movement after ambulation in 100% of the measurements, with 75% of the measurements showing no movement. ConclusionsThe MAC System is a mobile device that remained in place during ambulation and provided more consistent external mechanical compression in the desired range compared with the other three devices included in the present study.

Deep Venous Thrombosis With Symptomatic Bilateral Pulmonary Embolism After Using an Infrapatellar Strap for Patellofemoral Pain in an Athletic Cardiothoracic Surgeon.

Knee braces and patellar straps are frequently prescribed devices for treatment of patellofemoral pain syndrome. In this report, we describe the occurrence of localized deep venous thrombosis (DVT) after use of an infrapatellar strap. Until now, external mechanical compression has not been recognized as a cause of DVT. In young and athletic patients presenting with DVT, after exclusion of the most prominent risk factors, untraditional causes should be considered to mistakenly label a DVT as unprovoked.

External Compression and Partial Ischemia Decrease Human Finger Flexor Tendon and Subsynovial Connective Tissue Relative Motion.

Cumulative shear strain of the subsynovial connective tissue (SSCT) surrounding finger flexor tendons plays a significant role in the development and progression of carpal tunnel syndrome. Biomechanical risk factors can alter tendon-SSCT shear strain but the effects of external mechanical compression and localized ischemia have yet to be investigated. In a laboratory study with 19 healthy participants, color Doppler ultrasound imaging was used to quantify relative motion between the flexor digitorum superficialis tendon and SSCT during repetitive finger flexion-extension under various conditions of external mechanical compression (palmar and forearm compression), ischemia and different movement speeds (0.75 and 1.25 Hz). Forearm compression reduced tendon displacement (baseline = 28.5 ± 4.1 mm vs. forearm = 27.0 ± 4.6 mm; p = 0.043) and showed a trend for reduced SSCT displacement, while palmar compression had no significant effects on tendon-SSCT motion. Compared with baseline, partial ischemia decreased SSCT displacement (baseline = 22.9 ± 3.3 mm vs. ischemia = 22.0 ± 3.3 mm; p = 0.015), while tendon displacement remained unchanged. In all experimental conditions, faster movements elicited greater tendon-SSCT relative motion. Our findings suggest that palmar compression may not negatively impact tendon-SSCT relative motion, but forearm compression may require further investigation. Localized ischemia in the forearm may alter the gliding conditions within the carpal tunnel and affect tendon-SSCT relative motion, which bridges an important gap between blood flow in the carpal tunnel and shear injury risk. These findings contribute to the growing body of literature, supporting the role that cumulative tendon-SSCT shear injury may have on the pathomechanics of carpal tunnel syndrome. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:1038-1044, 2020.

1297 Cheers to Budd: Pyogenic Liver Abscess Complicated by Acute Budd-Chiari Syndrome

INTRODUCTION: Amebic liver abscess (ALA) is the most common extraintestinal manifestation of amebiasis with high mortality rates (20%). Complications include rupture; superinfection; anemia; and rarely vascular thrombosis. Budd-Chiari syndrome is characterized by post-sinusoidal portal hypertension caused by obstruction of either major hepatic veins or the inferior vena cava. CASE DESCRIPTION/METHODS: A 54-year-old alcoholic male, with a history of recent travel to India, presented with 2 weeks of fever, vomiting and abdominal pain. On exam, he was febrile, icteric, with generalized abdominal tenderness. Chemistries revealed WBCs 12000/mm3, total/direct bilirubin 6.5/3 mg/dL, AST/ALT 410/318 U/L, and ALP 310 U/L. USG RUQ showed hepatomegaly with multiple, thick-walled areas of central low attenuation, suspicious for LA. CT confirmed the presence of multiple ALAs along with rupture and delayed filling in the left and middle hepatic veins. Under USG guidance, brownish fluid (anchovy sauce-like) was aspirated and a pigtail catheter was placed. He was started on ceftriaxone and metronidazole for the treatment of pyogenic LA. Fluid serology was positive for Entamoeba histolytica and only metronidazole was continued for 21 days, along with rivaroxaban for six months for the treatment of Budd Chiari syndrome. His liver enzymes normalized in 21 days and a follow-up USG after 48 days of treatment with rivaroxaban showed no evidence of thrombosis in hepatic veins and IVC. DISCUSSION: ALA should be suspected in patients with fever &amp; jaundice with a history of recent travel to an endemic area. The rates of complications are high, commonest being an abscess rupture. Thrombosis of IVC, hepatic and sometimes right atrium, are rare complications, caused by either direct spread of inflammation or external mechanical compression by the abscess. A diagnosis of Budd-Chiari syndrome should be considered in cases of prolonged fever unresponsive to treatment or ascites with leg edema and collateral abdominal venous circulation. Underlying prothrombotic affection must be excluded. To conclude, identifying a treatable cause of Budd-Chiari syndrome, such as liver abscess, can result in early, effective, and life-saving treatment.

The Dynamics of Optical and Physiological Characteristics of Human Skin in vivo during Its Compression

The results of the study of the dynamics of optical and physiological properties of skin upon exposure to and removal of external mechanical compression, based on the analysis of temporal changes in diffuse reflectance spectra of human skin in vivo in the range of 400–2000 nm, are presented. In the spectral region of 500–600 nm (hemoglobin absorption region), the temporal dynamics of skin reflectance indicates that the skin compression causes an exponential decrease in the amount of blood in it, with an average time of blood displacement from the compression area of approximately 4–5 min. After compression removal, the skin blood filling exponentially recovers approximately within 30 s. In the spectral region of 700–2000 nm, skin reflectance after compression monotonically decrease according to two-exponential law with characteristic times of approximately 10 s and several minutes, which may be determined by the displacement of free and bound water from the compression area.

An observational study on survival rates of patients with out-of-hospital cardiac arrest in the Netherlands after improving the ‘chain of survival’

ObjectivesTo evaluate the impact of implemented procedures for out-of-hospital cardiac arrests (OHCAs) by determining patient outcome defined as the percentage return of spontaneous circulation at arrival at the emergency department,...

Динамика оптических и физиологических свойств кожи человека in vivo в процессе ее компрессии

The results of the study of dynamics of the optical and physiological properties of the human skin in vivo when applying and removing external mechanical compression based on the analysis of temporal changes in the diffuse reflectance spectra of human skin in the range of 400–2000 nm are presented. In the spectrum range 500–600 nm (hemoglobin absorption areas), the temporal dynamics of the skin reflectance coefficients show that skin compression leads to an exponential decrease in the blood content in the skin, while the average time for displacing blood from the compression region is about 4–5 min. After the compression is relieved, the blood filling of the skin is restored exponentially during a time of about 30 s. In the spectral range 700–2000 nm, the peculiarity of the skin reflectance coefficients after skin compression is applied is their monotonic decrease according to a two-exponential law with characteristic times of the order of 10 s and several minutes, which can be caused by the displacement of free and bound water from the compression region.

Age-associated impairments in contraction-induced rapid-onset vasodilatation within the forearm are independent of mechanical factors.

What is the central question of this study? We examined whether the mechanical contribution to contraction-induced rapid-onset vasodilatation (ROV) differed with age and whether ROV is associated with peripheral artery stiffness. Furthermore, we examined how manipulation of perfusion pressure modulates ROV in young and older adults. What is the main finding and its importance? The mechanical contribution to ROV is similar in young and older adults. Conversely, peripheral arterial stiffness is not associated with ROV. Enhancing perfusion pressure augments ROV to a similar extent in young and older adults. These results suggest that age-related attenuations in ROV are not attributable to a mechanical component and that ROV responses are independent of peripheral artery stiffness. Contraction-induced rapid-onset vasodilatation (ROV) is modulated by perfusion and transmural pressure in young adults; however, this effect remains unknown in older adults. The present study examined the mechanical contribution to ROV in young versus older adults, the influence of perfusion pressure and whether these responses are associated with arterial stiffness. Forearm vascular conductance (in millilitres per minute per 100mmHg) was measured in 12 healthy young (24±4years old) and 12 older (67±3years old) adults during: (i) single dynamic contractions at 20% of maximal voluntary contraction; and (ii) single external mechanical compression of the forearm (200mmHg) positioned above, at and below heart level. Carotid-radial pulse-wave velocity characterized upper limb arterial stiffness. Total ROV responses to single muscle contractions and single external mechanical compressions were attenuated in older adults at heart level (P<0.05); however, the relative mechanical contribution to contraction-induced peak (46±14versus 40±18%; P=0.21) and total (37±21versus 32±18%; P=0.27) responses were not different between young and older adults. Reducing or enhancing perfusion pressure altered ROV responses to a similar extent between young and older adults (P<0.05). Upper limb arterial stiffness was not associated with peak (r=0.02; P=0.93) or total vascular conductance (r=-0.01; P=0.96) in the group as a whole. Our data suggest that: (i) age-associated attenuations in ROV are not attributable to a mechanical component; (ii) enhancing perfusion pressure augments ROV to a similar extent between young and older adults; and (iii) basal upper limb arterial stiffness is not associated with the vasodilator responses after a single skeletal muscle contraction in young and older adults.

Core-Shelled Low-Oxidation State Oxides@Reduced Graphene Oxides Cubes Via Pressurized Reduction for Highly Stable Lithium Ion Storage

Metal oxides have been regarded as promising next-generation anode materials for rechargeable lithium ion batteries; however, their poor stability, which is caused by large volume changes during repeated lithiation/delithiation, remains a challenge. Here, conformally encapsulated low-oxidation state oxide cubes with reduced graphene oxide (RGO) obtained via a new pressurized reduction consisting of external mechanical compression and internal thermokinetic reduction from highly porous metal oxides/RGO aerogel (RGOA) are reported. Using single crystalline (SC) cobalt oxides and iron oxide cubes as model systems, the SC-Co3O4 or Fe2O3 cube/RGOA are pressurized into compacted xerogel along with a uniform thermokinetic reduction, which result in topotactic transformation to core-shelled CoO/RGO or Fe3O4@RGO cubes. The SC-CoO and SC-Fe3O4 cubes isolated perfectly in the RGO shells have dramatically improved their cycling stabilities for lithium ion storage to hundreds of times.

Are deformed neurons electrophysiologically altered? A simulation study

The electrophysiological outcome of neuron deformation is studied. This study is based on modeling the propagation of action potentials in a neuron with different deformed segments subject to an external mechanical compression. The proposed model is based on modified cable equation incorporating geometry variations. The study is performed for different degrees and number of deformations of the axon structure. The results of simulation show that the propagation speed, the refractory period, and the action potential broadening are all directly affected by variations in the geometry.

Cell Performance Determining Parameters in High Pressure Water Electrolysis

When hydrogen is used for energy applications, then often elevated pressure is required, i.e. up to 1000bar for hydrogen refueling stations. When polymer electrolyte electrolyzers are operated at elevated pressures, to reduce external mechanical compression needs, the thermodynamically expected cell voltage increase with pressure is not generally observed. Consequently, beneficial processes have to compensate for the increased work performed. In this paper, the influence of the operating pressure up to 100bar on the cell voltage behavior is investigated in detail. Data from galvanotstatic polarization curves up to 4A/cm2 combined with high frequency resistance measurements are analyzed using a zero-dimensional Tafel model. It shows that beneficial processes with increasing pressure are related to both the kinetic and mass transport overpotentials. At current densities above 1A/cm2 about two thirds of the overpotential gain can be related to reaction kinetics. Based on the Tafel model approach an increase of the apparent exchange current density by a factor of 4 to 7 is observed for the pressure increase from 10 to 100 bar. In contrast, the Tafel slope is independent of pressure and only the expected increase with temperature (73 to 81mV/dec) for 30 to 70°C is observed. Mass transport losses decrease with pressure. At 50°C and 2A/cm2, increasing the pressure from 1 to 100bar results in a decrease of the mass transport overpotential from 130 to 80mV.