The effects of leg/body position on transcutaneous oxygen measurements after lower-extremity arterial revascularization.

A postoperative nursing goal in a patient with peripheral artery disease requiring lower-extremity arterial reconstruction surgery is to maintain blood flow and tissue oxygenation to the revascularized extremity. This may be achieved through extremity positioning. Transcutaneous oxygen (TcPO(2)) measurements provide a noninvasive objective determination of oxygen at the skin surface and assessment of underlying circulation and tissue oxygenation. The purpose of this study was to determine which lower-extremity position afforded the highest TcPO(2) in 10 subjects with a lower-extremity arterial revascularization procedure preoperatively and 24 and 48 hours postoperatively. Hypotheses included comparing preoperative and postoperative TcPO(2) measurements, leg skin temperatures, and limb volumes. The subjects were studied in three different leg/body positions: supine with legs extended, sitting with legs extended, and supine with legs-elevated 20 degrees using the Radiometer TCM30 (Radiometer; Copenhagen) and PhysitempTH-5 Thermalert (Physitemp; Clifton, NJ) monitors. There was no change in the postoperative leg TcPO(2) measurements or limb volumes compared with preoperative measurements (P = .12-.92). A small sample size and lack of peripheral artery disease stratification were among study limitations. Significant to the nursing care of patients with vascular dsease is the finding that any of the leg/body positions in this study could be used postoperatively on the revascularized extremity without decreasing TcPO(2) measurements.     

Early detection of microcirculatory impairment in diabetic patients with foot at risk

OBJECTIVE: To assess microcirculatory impairment and alterations of the skin oxygen supply in diabetic patients with foot at risk. RESEARCH DESIGN AND METHODS: This study evaluated skin blood flow in 21 type 2 diabetic patients with a foot at risk (defined as a foot with neuropathy but without ulceration or previous ulcerations), 20 type 2 diabetic patients without foot lesions or neuropathy, and 21 normal subjects as a control group. The skin blood flow was determined by measuring the transcutaneous oxygen pressure (TcPO(2)) at the dorsum of the foot in supine and sitting position. The clinical assessment included standard measures of peripheral and autonomic neuropathy, but peripheral vascular disease was excluded by Doppler ultrasound. RESULTS: In supine position, TcPO(2) was significantly reduced (means +/- SE) in diabetic patients with foot at risk (6.04 +/- 0.52 kPa) compared with diabetic (7.14 +/- 0.43 kPa, P = 0.035) and nondiabetic (8.10 +/- 0.44 kPa, P = 0.01) control subjects. The sitting/supine TcPO(2) difference was higher in diabetic subjects with foot at risk (3.13 +/- 0.27 kPa) compared with both diabetic (2.00 +/- 0.18, P = 0.004) and nondiabetic (1.77 +/- 0.15 kPa, P = 0.0003) control subjects. The mean sitting/supine ratio was 1.70 +/- 0.12 in diabetic patients with foot at risk, 1.32 +/- 0.04 in diabetic control subjects, and 1.25 +/- 0.03 in nondiabetic control subjects (P = 0.007). The sitting/supine TcPO(2) ratio was negatively correlated with the heart rate variation coefficient at rest (r = -0.32, P = 0.044) and at deep respiration (r = -0.31, P = 0.046). CONCLUSIONS: Our data indicate that skin oxygen supply is reduced in type 2 diabetic patients with foot at risk. This is probably due to an impaired neurogenic blood flow regulation and may contribute to capillary hypertension, followed by disturbed endothelial function leading to edema and skin damage of the foot. The determination of TcPO(2) appears to be a useful tool in screening type 2 diabetic patients for foot at risk.     

Effect of body position on foot and ankle volume in healthy subjects

Physical therapy treatments for and evaluation of lower limb swelling are usually performed in supine lying position. However, the limb is usually treated or assessed in the dependent position, i.e. sitting or standing. The purpose of this study was to determine the possible confounding effect of subject positioning on foot and ankle volume. Sixty healthy individuals were randomly positioned into motionless standing, sitting or supine lying for 30 min. Volumetric measurements of the dominant leg were taken with a foot and ankle volumeter before and after 30 min of positioning. A significant difference between the three groups for foot and ankle volume change (F(2,53) = 35.41, P<0.001) was found. A post-hoc Tukey HSD test revealed that the difference was statistically significant between sitting and standing as well as supine lying and standing (P<0.001). No statistical significance was found between sitting and supine lying (P = 0.90). Standing caused the greatest increase in foot and ankle volume followed by sitting then supine lying. The results indicate that treating or assessing a limb with the subject in a sitting position would not be significantly different from a subject who is positioned in supine lying. However, it is not known whether the height and the distance from the heart to the feet were comparable between the groups, and so it is recommended that, where possible, treatment and assessment of lower leg swelling should be undertaken with the leg in a non-dependent position and definitely not in standing.     

Reliability of transcutaneous oxygen tension (TcPO2) measurements in elderly normal subjects

This study was conducted to evaluate the reliability of TcPO2 measurements in a well characterized group of 10 elderly normal subjects with an age distribution typical for the population with peripheral vascular disease (PVD) and amputation. The TcPO2 values were obtained on three separate occasions at 2-week intervals at seven anatomic sites commonly measured in patients with PVD. The TcPO2 values were comparable to those previously reported for similar sites in normal elderly subjects. Measurement to measurement variation averaged 1.1 kPa (8 mmHg) for a coefficient of variation (CV) of 14.4%. Confidence intervals ranging from 2.1 kPa (16 mmHg) above a single TcPO2 value to 2.1 kPa (16 mmHg) below were necessary to contain the true value 95% of the time. While TcPO2 measurement is assuming an important role in the evaluation of disease states in both paediatric and adult medicine, our observations emphasize the importance of using such measurements as an adjunct in clinical decision making and not basing such decisions on a single TcPO2 value alone. The size of the confidence intervals can be reduced substantially for a given site by taking the mean of two or more TcPO2 measurements taken at separate times.     

Peripheral artery disease, diabetes, and reduced lower extremity functioning.

OBJECTIVE: To characterize lower extremity function and dysfunction in peripheral artery disease (PAD) patients with and without diabetes. RESEARCH DESIGN AND METHODS: In this cross-sectional study, 460 men and women with PAD (147 with diabetes) were recruited from three academic medical centers. Assessments included ankle brachial index (ABI), neuropathy score, 6-min walk distance, 4-m walking velocity, Walking Impairment Questionnaire (0-100 scale, 100 = best), and summary performance score (SPS) (0-12 scale, 12 = best). RESULTS: The mean ABI was similar in PAD patients with and without diabetes. PAD patients with diabetes were younger, had a higher BMI, had a worse neuropathy score, and had a greater number of cardiovascular comorbidities compared with those without diabetes. Participants with diabetes were less likely to report classical symptoms of intermittent claudication and more likely to report exertional leg pain, which sometimes started at rest. After adjusting for age, those with diabetes had a shorter mean 6-min walk distance (1,040 vs. 1,168 feet, P < 0.001), slower fast-pace 4-m walk velocity (0.83 vs. 0.90 m/sec, P < 0.001), and a lower SPS (7.3 vs. 8.6, P < 0.001) than those without diabetes. Patients with diet-controlled diabetes performed better than those on diabetes medications. Differences in lower extremity functioning between patients with and without diabetes were largely attenuated but not abolished for SPS and fast-pace 4-m walk velocity after adjustment for type of exertional leg pain, neuropathy score, and number of cardiovascular comorbidities. CONCLUSIONS: Subjects with PAD and diabetes have poorer lower extremity function than those with PAD alone. This difference in functioning appears to be largely explained by diabetes-associated neuropathy, differences in exertional leg symptoms, and greater cardiovascular disease in patients with diabetes.     

左右臂踝脉搏波传播速度绝对差值诊断外周动脉疾病的价值

目的探讨并发外周动脉疾病（PAD）的糖尿病患者下肢动脉臂踝脉搏波传播速度（baPWV）的改变情况。方法102例健康对照组和101例2型糖尿病患者（包括PAD患者）。用动脉硬化诊断仪测量baPWV和踝肱比值（ABI）。结果无并发PAD的糖尿病患者baPWV高于健康对照组（中位数1640与1110cm/s,P〈0.05）。并发PAD的糖尿病患者,患肢baPWV低于非患肢baPWV（中位数1300与1650cm/s,P〈0.05）。对于同年龄组患者（50-70岁）,并发PAD的糖尿病患者患肢baPWV（中位数1300与1640cm/s,P〈0.05）和ABI（中位数0.8与1.1,P〈0.05）均比无并发PAD的糖尿病患者低。并发PAD的糖尿病患者左右baPWV绝对差值均较无并发PAD者大（均P〈0.05）。并发PAD的糖尿病患者左右baPWV绝对差值与患肢ABI呈负相关（rs=-0.586,P〈0.05）。结论糖尿病患者baPWV增加,而并发PAD后患肢baPWV降低,左右baPWV绝对差值可能用于PAD的诊断。     

Changes in motoneuron excitability in hemiplegic subjects after passive exercise when using a robotic arm

OBJECTIVE: To test the hypothesis that motoneuron excitability in stroke subjects is influenced by peripheral sensory input through passive exercise to the hemiplegic upper extremity. DESIGN: Case-control prospective study. SETTING: Physical medicine and rehabilitation inpatient and outpatient clinic at a tertiary Veterans Affairs medical center. PARTICIPANTS: Nineteen hemiplegic adult subjects with a history of a cerebrovascular event. INTERVENTION: A standardized passive exercise program was performed on the right upper extremity by using a robotic arm. Nerve conduction study of the median nerve was obtained before and after the exercise. Maximum onset and peak amplitudes of the Hoffmann reflex (Hmax) and motor response (Mmax) wave were recorded. MAIN OUTCOME MEASURES: Hmax, Mmax, and Hmax/Mmax ratio. RESULTS: Immediately after passive exercise, there was no significant alteration in the Hmax (P=.94), Mmax (P=.60), or Hmax/Mmax ratio (P=.53) as compared with pre-exercise evoked responses. CONCLUSIONS: Peripheral proprioceptive input with passive exercise does not cause appreciable change in the Hmax/Mmax ratio, suggesting that motoneuron excitability of the affected upper extremity in stroke subjects is not influenced by passive robotic intervention.     

Peak expiratory flow in healthy,young, non-active subjects in seated,supine, and prone postures

Objective: To compare the PEFs in healthy, young, non-active subjects in seated, supine, and prone postures. Methods: A total of 30 healthy volunteers (15 male, mean age 22.7 years, non-smokers, sedentary) underwent a physical examination, spirometry to confirm normal pulmonary function, and PEF using the Mini-Wright Peak Flow Meter while wearing a nose clip. PEF measurements were repeated three times in each of three positions (seated, prone, and supine) in random order and differed by less than 20 L/min for a given position. Paired Student’s t-tests were used to analyze the results, and the significance level was set at 5%. Results: The PEF values obtained when the study participants were in a seated position (481.0 ± 115.1 L/min) were higher than those obtained when participants were in prone (453.7 ± 112.1 L/min) or supine (453.2 ± 114.3 L/min) positions (p < 0.05). No significant difference in PEF values was observed between the prone and supine positions. Conclusion: Body posture affects PEF in healthy, young, non-active subjects. PEFs are higher when subjects are in a seated position compared to prone or supine positions, but no difference in PEF is observed between the prone and supine positions.     

糖尿病足下肢血运重建技术与治疗策略

随着糖尿病患病率逐年升高,患有糖尿病的慢性威胁性肢体缺血（chronic limb-threatening ischemia,CLTI的发病率也呈上升趋势。在多达50%的糖尿病足溃疡患者中可以观察到外周动脉疾病（peripheral arterial disease,PAD）的症状或体征,同时PAD也是伤口愈合不良和截肢的危险因素。治疗患有糖尿病的PAD患者更困难,因为其更易发生长节段闭塞、严重钙化且更多累及远端。因此,针对这些患者的治疗策略与其他PAD患者应该有所区分。最近研究强调了糖尿病足患者的不同血运重建方法、治疗技术、设备及其疗效,这些治疗方式与技术有望缓解缺血性疼痛,治愈足部溃疡,降低截肢率和缩小截肢范围,并改善患者的功能和生活质量。本文对糖尿病足患者下肢血运重建不同治疗方式临床数据进行分析,讨论不同方式的优点,详细介绍糖尿病足下肢血运重建策略,还关注了可用于糖尿病足下肢血运重建的最新治疗技术和设备,旨在提供较为全面的糖尿病足下肢血运重建研究进展。     

自体外周血干细胞移植治疗糖尿病下肢缺血效果观察

目的 探讨自体外周血干细胞(PBSC)移植治疗糖尿病性下肢缺血的疗效。方法 应用自体PBSS移植治疗18例30条糖尿病性下肢缺血。采用主观、客观评价指标对疗效进行观察评定。结果 自体PBSC移植后1个月患者疼痛、冷感、麻木症状明显改善,改善率分别为96.7％ (29/30)、100％(30/30)、95.8％ (23/24);间歇性跛行明显缓解,总有效率为76.9％ (10/13)。3个月后踝肱指数(ABI)升高,由术前的0.60±0.11增加到术后的0.71±0.12,差异有统计学意义(t=-6.882,P＜0.01)。93.3％(28/30)的患者皮氧分压不同程度地升高;同时患者的足部感染得到控制,溃疡或足趾坏疽好转或愈合。移植后所有患者均未出现并发症和明显不良反应。结论 自体PBSC移植治疗糖尿病性下肢缺血是一种相对简单、安全、有效的方法。     

RELIABILITY,COMPARABILITY, AND VALIDITY OF FOOT INVERSION AND EVERSION STRENGTH MEASUREMENTS USING A HAND-HELD DYNAMOMETER

Background

There are conflicting results with respect to the validity and reliability of lower extremity strength measurements using a hand-held dynamometer (HHD) in the healthy population. Previous studies exploring foot inversion and eversion strength using a HHD were carried out with predominantly clinically affected participants in different positions. The question arises whether HHD measurements of isometric foot inversion and eversion strength performed with participants in different positions are valid, reliable and comparable and can be used alternatively.

Purpose

The aims of this study were to investigate: a) the intra- and inter-tester reliability of measurements of foot inversion and eversion strength in different participant positions using a belt-stabilized HHD; b) the comparability of results obtained in different positions; and c) the concurrent validity of the aforementioned measurements using an isokinetic dynamometer.

Methods

Thirty adults (12 females and 18 males; mean age 22.5 ± 3.9 years) volunteered to participate in this study. Maximal isometric foot inversion and eversion torques (Nm) were measured with participants lying supine, sitting with knees extended and lying on their side using a belt-stabilized HHD. Measurements were performed independently by two physiotherapists over two days and were repeated using an isokinetic dynamometer. Validity and intra- and inter-tester reliability were determined using the intra-class correlation coefficient (ICC). A two-way ANOVA (p < 0.05) and post-hoc tests with Bonferroni correction were used to compare data from different positions. Bland-Altman plots were used to demonstrate the range of error and difference between HHD and isokinetic measurements.

Results

Intra-tester reliability for inversion and eversion torques was fair to excellent in all positions (ICC = 0.598–0.828). Excellent inter-tester reliability was found for eversion torques in all positions (ICC = 0.773–0.860). For inversion torques, inter-tester reliability was fair to excellent (ICC = 0.519–0.879). ICC values of 0.205 to 0.562 indicated a low to fair concurrent validity. A significant difference was observed between the torques of the supine and side-lying positions as well as sitting and side-lying positions (p < 0.05). Bland-Altman plots showed that the mean of the differences for inversion and eversion torques deviates considerably from zero, indicating that measurements with the HHD in the three positions produce lower values compared to using the isokinetic dynamometer.

Conclusions

Inversion and eversion strength measurements with subjects in different positions using HHD seem to be reliable, but consistently underestimated torque output when compared with measurements using isokinetic dynamometry. While the HHD outcomes measured in supine and sitting positions seem to be comparable, those measured in supine/sitting and side-lying positions differed.

Level of Evidence

Diagnostic study, Level 3     

Effects of different sitting positions on skin temperature of the lower extremity

[Purpose] The purpose of this study was to identify the effect of different sitting positions on the skin temperature of the lower extremity. [Subjects] The subjects of this study were 23 healthy university students (8 males, 15 females). [Methods] Normal sitting (NS), upper leg cross (ULC) and ankle on knee (AOK) positions were conducted to measure the changes in skin temperature using digital infrared thermographic imaging (DITI). [Results] ULC upper ankle, NS upper shin, ULC upper shin and NS lower shin showed significant declines in temperature with time. [Conclusion] These finding suggest that the ULC and NS sitting positions cause decline of blood flow volume to the lower extremity resulting in decrease of temperature of the lower extremity. Especially, sitting with the legs crossed interferes with the circulation of blood flowing volume much more than just sitting in a chair.Key words: Sitting position, Skin temperature, Blood flow     

Subcutaneous and intramuscular pressures in the post-phlebitic limb

The mechanisms of pain in patients with chronic iliac vein obstruction and venous claudication is not fully understood. Ten patients with severe to moderate unilateral post-thrombotic syndrome with chronic iliac vein obstruction were studied. Subcutaneous tissue pressures and intramuscular pressures were measured using the slit-catheter technique in both legs, at rest and during exercise. The subcutaneous tissue pressure was higher, but not significantly higher, in the leg with iliac vein obstruction, +2 (-2 to +10) mmHg, than in the contralateral healthy legs, 0 (-4 to +4) mmHg in supine position at rest. During exercise in the standing position the subcutaneous tissue pressure rose significantly (p less than 0.01) in the diseased leg to 9 (+4 to +15) mmHg, while no such increase was seen in the control limb, 0 (-4 to +4) versus -1 (-5 to +4) mmHg. The intramuscular pressures were significantly higher (p less than 0.01) in the leg with iliac vein obstruction 26 (15 to 42) mmHg, than in the control leg, 11 (1 to 15) mmHg at rest in supine position as well as during exercise in standing position, 64 (35 to 82) mmHg and 26 (10 to 36) mmHg, respectively.     

Preamputation evaluation of limb perfusion with laser Doppler imaging and transcutaneous gases

We studied 31 subjects with severe leg ischemia and 29 age-matched nonischemic control subjects to compare preamputation assessments of leg ischemia using laser Doppler imaging (LDI), transcutaneous partial pressure of oxygen (TcPO(2)), and transcutaneous partial pressure of carbon dioxide (TcPCO(2)). TcPO(2) and TcPCO(2) were evaluated with Novametrix Medical Systems, Inc, monitors (Wallingford, Connecticut) and perfusion (flux) of skin topically heated to 44 degrees C, and adjacent nonheated areas were evaluated with a Moor Laser Doppler Imager (Moor Instruments, Ltd; Devon, England). LDI flux of heated areas, its ratio to nonheated areas, and TcPO(2) (not TcPCO(2)) were lower in ischemic subjects than in control subjects. LDI flux ratio performed better than TcPO(2) in identifying ischemia, with fewer false positive and false negative results. Moreover, LDI flux of heated skin detected a proximal to a distal gradient of perfusion in ischemic subjects, while TcPO(2) did not. LDI was superior to TcPO(2) in discriminating correctly between ischemic and nonischemic skin. The results suggest that an LDI ratio below 5 indicates nonviable skin.     

Effect of posture on baroreflex sensitivity in healthy subjects

Summary. In this study we investigated whether body position has significant effects on baroreflex sensitivity in healthy subjects. Baroreflex sensitivity was calculated from pressure overshoot after the release of a Valsalva strain in the supine and sitting positions in 10 subjects. At rest, no difference was found in supine and sitting mean R-R intervals (837±82 and 858±86 ms, respectively), whereas systolic and diastolic blood pressures were lower in the supine position (111.3±24.6 vs. 141.2±12.6 mmHg, P<0.01 and 54.8±14.7 vs. 75.6±13.4 mmHg, P<0.001, respectively). Baroreflex sensitivity in the supine (9.0±4.1 ms±mmHg^-1) and sitting positions (8.8±4.9 msXmmHg^-1) did not differ significantly from each other. The correlation between supine and sitting baroreflex sensitivity was 0.96 (P<0.001) and in 9 out of 10 subjects the discrepancy between supine and sitting baroreflex sensitivity was <2.0 ms±mmHg^-1. We conclude that baroreflex sensitivity measured in the supine and sitting positions do not differ significantly from each other.     

Bilateral photoplethysmography studies of the leg arterial stenosis

A newly developed portable multi-channel photoplethysmography (PPG) device has been used for comparative studies of 20 healthy control subjects and 45 patients with diagnosed arterial stenosis in a leg. The peripheral blood pulsations were detected simultaneously at four body sites-the same fingers and toes of both arms and legs. The PPG pulses recorded at the periphery of the stenotic leg, if compared with those of the healthy leg, were much weaker, with delayed arrival as a consequence of increased pulse wave transit time (PWTT) due to higher vascular resistance. The specific PWTT delays for the occluded legs were in the range of 20-80 ms, while in the case of healthy subjects the leg PPG signals arrived without delays or with smaller time-shifts not exceeding 14 ms. The reference bilateral PPG signals detected at the fingertips did not show any notable PWTT delays in both groups. Parallel measurements of local blood pressures by means of the oscillometry method with subsequent calculation of the ankle-brachial index were performed. Convincing correlation between the bilateral differences in the local blood pressure (a routine tool for diagnostics of leg stenosis) and in the corresponding PWTT delay (Pearson's coefficient r = 0.93), as well as between the PWTT delay and the ankle-brachial index (r = -0.96) has been established. From the point of view of PWTT delay, the average value of leg stenosis diagnostic threshold was established to be in the range of 23 +/- 9 ms, with full reliability above 32 ms. The obtained data may find further applications in alternative methodologies for detection and/or assessment of arterial occlusions in human extremities.     

Changes in human plasma atrial natriuretic polypeptide concentration in normal subjects during passive leg raising and whole-body tilting

The effect of central venous pressure on release of human atrial natriuretic polypeptide (hANP) was studied by measuring the plasma hANP levels during passive leg raising to 60 degrees and head up whole-body tilt at 60 degrees in normal volunteers. In ten subjects, after at least 1 h recumbency, both legs were raised passively 60 degrees for 20 min. While the legs were raised the plasma hANP level increased significantly from a basal level of 101 +/- 10 pg/ml (mean +/- SE) to a peak of 165 +/- 15 pg/ml after 10 min, and returned to the basal level 10 min after the legs were lowered. The blood pressure and pulse rate were not affected by raising the legs. The effect of head up whole-body tilt of 60 degrees from the supine position, for 20 min, was examined in nine normal subjects. Their plasma hANP decreased transiently at 5 min in five of them and at 10 min or later in the remaining four subjects. Their blood pressure did not change but their pulse rate increased significantly while their body was being tilted. These results suggest that secretion of hANP is regulated physiologically by changes in the central venous pressure.