Functional claudication distance: a reliable and valid measurement to assess functional limitation in patients with intermittent claudication

BACKGROUND: Disease severity and functional impairment in patients with intermittent claudication is usually quantified by the measurement of pain-free walking distance (intermittent claudication distance, ICD) and maximal walking distance (absolute claudication distance, ACD). However, the distance at which a patient would prefer to stop because of claudication pain seems a definition that is more correspondent with the actual daily life walking distance. We conducted a study in which the distance a patient prefers to stop was defined as the functional claudication distance (FCD), and estimated the reliability and validity of this measurement. METHODS: In this clinical validity study we included patients with intermittent claudication, following a supervised exercise therapy program. The first study part consisted of two standardised treadmill tests. During each test ICD, FCD and ACD were determined. Primary endpoint was the reliability as represented by the calculated intra-class correlation coefficients. In the second study part patients performed a standardised treadmill test and filled out the Rand-36 questionnaire. Spearman's rho was calculated to assess validity. RESULTS: The intra-class correlation coefficients of ICD, FCD and ACD were 0.940, 0.959, and 0.975 respectively. FCD correlated significantly with five out of nine domains, namely physical function (rho = 0.571), physical role (rho = 0.532), vitality (rho = 0.416), pain (rho = 0.416) and health change (rho = 0.414). CONCLUSION: FCD is a reliable and valid measurement for determining functional capacity in trained patients with intermittent claudication. Furthermore it seems that FCD better reflects the actual functional impairment. In future studies, FCD could be used alongside ICD and ACD

Randomized controlled trial of supervised exercise to evaluate changes in cardiac function in patients with peripheral atherosclerotic disease

Introduction: Peripheral atherosclerotic disease (PAD) is a condition characterized by low functional capacity which is associated with impaired free living, ambulation and low exercise tolerance. The purpose of this randomized controlled study was to evaluate whether changes in maximal walking time are associated with adaptations in cardiovascular function following supervised exercise. Methods: After ethics approval, 28 patients (63±11 years) completed a graded treadmill test (2min stages, 3.2 kmh-1, with gradient increasing 2% every 2min) until they reached level three or four on the claudication pain scale. Peak oxygen consumption was assessed on a breath-by-breath basis, by online expiratory gas analysis. Following a 40-min recovery period, peak cardiac output was measured using the non-invasive carbon dioxide rebreathing method described by Defares (J Appl Physiol, 13, 1958, 159). Peak cardiac power output was then computed using the equation described by Cooke et.al. (Heart, 1998, 79, 289). Patients were randomly assigned to one of two groups: supervised, who exercised at the hospital twice weekly for 12weeks or control, who received normal treatment which included encouragement to walk regularly. Results: After 12 weeks, there were no significant changes in body mass, peak oxygen consumption, peak cardiac output, peak heart rate, peak cardiac power output, respiratory exchange ratio or rating of perceived exertion in both the supervised and control group. There was a significant improvement (91%) in maximal walking distance following the supervised exercise programme. Although patients'peak cardiovascular measurements were unchanged, the patients in the supervised exercise group were able to complete a higher workload at the end of the 12 weeks of exercise, for the equivalent demands on the circulation system. Conclusions: The findings from this study suggest that a short-term period of supervised exercise training results in an improved walking time in patients with limiting claudication because of PAD. It also demonstrated that the cardiovascular system becomes more efficient in meeting the demands of exercise. It is recommended that individuals with PAD should undertake exercise as a form of treatment. © 2007 The Authors Journal compilation © 2007 Blackwell Publishing Ltd

Comments on the Bilderberg Continuum Atmosphere

The Bilderberg Continuum Atmosphere fails to reproduce the observed limb-darkening throughout the range of wavelengths 4500 Å< λ < 25 000 Å. The temperature-pressure diagram for the deep layers of this model is a curve which is flatter than the relation predicted from the mixing length theory. A modification of the Bilderberg Continuum Atmosphere that improves representation of the observations and theoretical results is proposed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43730/1/11207_2004_Article_BF00154247.pd

Earth-air Heat Exchanger Potential Under Future Climate Change Scenarios in Nine North American Cities

Earth–air heat exchanger (EAHE) potential was evaluated for nine locations representing a range of North American climates to determine the impact of futureclimatescenarios.ThiswasmotivatedbytheintrinsicrelationshipbetweenclimateconditionsandEAHEpotential.Futureweatherfileswerecreatedusinggeneral circulation model (GCM) outputs for three representative concentration pathways (RCP) scenarios and two separate timeframes. These were used in a climate-based approach for estimating EAHE potential based on their capacity to provide either heating or cooling. The results demonstrated, cooling capacity of a hypothetical EAHE system decreased and heating capacity increased due to changes in demand. The largest effects were observed for later time periods and more drastic changes to radiative forcing. From the chosen locations, heating dominated sites are most susceptible to unfavorable changes in cooling capacity due to the synchronous timing of changes in cooling capacity relative to peak demand. This work highlights the importanceofconductingaclimatechangeimpactassessmentonEAHEpotentialin theseclimatestoensuresystemeffectivenessintothefuture.Furtherworkisrequired to explore the impact of depth and efficiency in addition to the resolution of climate changes models used

Development of solar-blind AlGaN 128x128 ultraviolet focal plane arrays

This paper reports the development of solar-blind aluminum gallium nitride (AlGaN) 128x128 UV Focal Plane Arrays (FPAs). The back-illuminated hybrid FPA architecture consists of an 128x128 back-illuminated AlGaN PIN detector array that is bump-mounted to a matching 128x128 silicon CMOS readout integrated circuit (ROIC) chip. The 128x128 p-i-n photodiode arrays with cuton and cutoff wavelengths of 233 and 258 nm, with a sharp reduction in response to UVB (280-320 nm) light. Several examples of solar-blind images are provided. This solar-blind band FPA has much better application prospect