A descriptive study of skin temperature, tissue perfusion, and tissue oxygen in patients with chronic venous disease

Photonic and magnetic materials for on-demand local drug delivery

Nanomedicine has been considered a promising tool for biomedical research and clinical practice in the 21st century because of the great impact nanomaterials could have on human health. The generation of new smart nanomaterials, which enable time- and space-controlled drug delivery, improve the limitations of conventional treatments, such as non-specific targeting, poor biodistribution and permeability. These smart nanomaterials can respond to internal biological stimuli (pH, enzyme expression and redox potential) and/or external stimuli (such as temperature, ultrasound, magnetic field and light) to further the precision of therapies. To this end, photonic and magnetic nanoparticles, such as gold, silver and iron oxide, have been used to increase sensitivity and responsiveness to external stimuli. In this review, we aim to report the main and most recent systems that involve photonic or magnetic nanomaterials for external stimulus-responsive drug release. The uniqueness of this review lies in highlighting the versatility of integrating these materials within different carriers. This leads to enhanced performance in terms of in vitro and in vivo efficacy, stability and toxicity. We also point out the current regulatory challenges for the translation of these systems from the bench to the bedside, as well as the yet unresolved matter regarding the standardization of these materials.

Pressure Injury Link to Entropy of Abdominal Temperature

This study examined the association between pressure injuries and complexity of abdominal temperature measured in residents of a nursing facility. The temperature served as a proxy measure for skin thermoregulation. Refined multiscale sample entropy and bubble entropy were used to measure the irregularity of the temperature time series measured over two days at 1-min intervals. Robust summary measures were derived for the multiscale entropies and used in predictive models for pressure injuries that were built with adaptive lasso regression and neural networks. Both types of entropies were lower in the group of participants with pressure injuries (n=11) relative to the group of non-injured participants (n=15). This was generally true at the longer temporal scales, with the effect peaking at scale τ=22 min for sample entropy and τ=23 min for bubble entropy. Predictive models for pressure injury on the basis of refined multiscale sample entropy and bubble entropy yielded 96% accuracy, outperforming predictions based on any single measure of entropy. Combining entropy measures with a widely used risk assessment score led to the best prediction accuracy. Complexity of the abdominal temperature series could therefore serve as an indicator of risk of pressure injury.

Transcutaneous Partial Pressure of Oxygen Measurement in Advanced Chronic Venous Insufficiency as a Marker of Tissue Oxygenation

Purpose

Determination of oxygen concentration in tissues affected by chronic venous insufficiency (CVI) has shown inconsistent results over the years and has confounded the pathophysiology of venous diseases. This study measured transcutaneous partial oxygen pressure (TcPO₂) levels in patients with CVI to assess oxygenation and variation in oxygenation according to CVI stage.

Methods

Materials and A prospective study was performed on consecutive patients with unilateral CVI. TcPO₂ of diseased and unaffected limbs was measured in the supine and dependent positions. A single TcPO₂ value was measured at the site of greatest skin change or at the edge of the ulcer. The TcPO₂ values were analyzed and compared according to stage.

Results

A total of 96 patients were included in the study with C4 (24.0%), C5 (19.8%), and C6 (56.3%) disease. The mean age was 44.7 years, and 85 (88.5%) were male. There was a statistically significant (P<0.01) difference in mean TcPO₂ levels between the unaffected limb (supine, 32.1 mmHg; dependent, 50.7 mmHg), C5 diseased limb (supine, 16.6 mmHg; dependent, 35.5 mmHg), and C6 diseased limb (supine, 24.2 mmHg; dependent, 40.4 mmHg). In the supine and dependent positions, the mean TcPO₂ in the affected limb was significantly lower (P<0.01) than that in the unaffected limb.

Conclusion

TcPO₂ in advanced CVI can be used as a marker of oxygenation status. This is the first study in an Indian population looking at the relevance of TcPO₂ in the prognostication of advanced CVI.

Integrated non-invasive biochemical and biophysical sensing systems for health and performance monitoring: A systems perspective

Advances in materials, bio-recognition elements, transducers, and microfabrication techniques, as well as progress in electronics, signal processing, and wireless communication have generated a new class of skin-interfaced wearable health monitoring systems for applications in personalized medicine and digital health. In comparison to conventional medical devices, these wearable systems are at the cusp of initiating a new era of longitudinal and noninvasive sensing for the prevention, detection, diagnosis, and treatment of diseases at the molecular level. Herein, we provide a review of recent developments in wearable biochemical and biophysical systems. We survey the sweat sampling and collection methods for biochemical systems, followed by an assessment of biochemical and biophysical sensors deployed in current wearable systems with an emphasis on their hardware specifications. Specifically, we address how sweat collection and sample handling platforms may be a rate limiting technology to realizing the clinical translation of wearable health monitoring systems; moreover, we highlight the importance of achieving both longitudinal sensing and assessment of intrapersonal variation in sweat-blood correlations to have the greatest clinical impact. Lastly, we assess a snapshot of integrated wireless wearable systems with multimodal sensing capabilities, and we conclude with our perspective on the state-of-the-art and the required developments to achieve the next-generation of integrated wearable health and performance monitoring systems.

Infrared thermography to prognose the venous leg ulcer healing process-preliminary results of a 12-week, prospective observational study

Venous leg ulcers are complex, and their multifactorial etiology make successful treatment a difficult and long process. Nonhealing ulcers are the greatest challenge because they are resistant to standard therapies. In this study, we analyzed whether monitoring the temperature of the ulcered limb wound area could benefit the diagnosis of the wound's tendency to heal (estimating the presence of a healing or nonhealing wound) in patients with two-sided venous leg ulcers. This prospective, 12-week observational study included 57 adult individuals with chronic venous leg ulcers. The dynamics of wound healing was assessed by planimetry and infrared thermography every two weeks. We analyzed temperatures measured at three marked areas-the wound, the periwound skin, and the reference area. An initial wound area larger than 1 cm² was associated with a temperature increase of 0.027 °C in the periwound skin. A 1-cm² decrease in the wound area was associated with a 0.04 °C decrease in the temperature difference between the periwound skin and wound. A strong positive relationship was identified for both the bacteriology variables (the presence of bacteria: temperature increase in the periwound skin of 0.4 °C, p < 0.001; the number of bacterial species in a wound, temperature increase of 0.95 °C, p < 0.001). The temperature in the reference area was significantly correlated with the failure of the superficial and perforating veins (temperature increase of 0.69 °C, p = 0.04). This study reports that the assessment of the temperature a limb may be beneficial in predicting whether an ulcer is a healing or a nonhealing ulcer. The decrease in the temperature differences between the areas referred to as healing wounds was the only beneficial prognostic marker. Other temperature differences in the periwound skin were caused by disorders, such as multibacterial wound infections and superficial venous inflammation.

Effects of compression therapy and venous surgery on tissue oxygenation in chronic venous disease

Objectives

This study aimed to determine if compression therapy or surgical intervention improves tissue oxygenation in chronic venous disease.

Method

Thirty lower limbs with chronic venous disease were placed into three groups, being compression, open surgical and endovenous ablation. Tissue oxygenation was assessed using a hyperspectral transcutaneous oxygen measurement system. Measurements were recorded at baseline and 28 days following therapy.

Results

Fourteen patients completed the study; therefore, the cohort was re-categorised into two groups: compression therapy and surgical. There were no differences in demographics and baseline hyperspectral transcutaneous oxygen measurement. In compression therapy, skin perfusion was enhanced in all locations in the supine position and lateral malleolus in standing position. Skin temperature (°C) increased in all locations. In the surgical group, oxyhaemoglobin and oxyhaemoglobin saturation increased at the medial malleolus in standing position; however, no other significant improvements were identified.

Conclusions

Compression increased tissue oxygenation and skin temperature to a greater extent than surgical intervention. This supports the importance of compression therapy in chronic venous disease.

Quantifying and Trending the Thermal Signal as an Index of Perfusion in Patients Sedated with Propofol

We examined the feasibility of a thermal imager smart phone attachment as a potential proxy of skin perfusion by assessing shifts in skin temperature following administration of the vasodilatory anesthetic propofol. Four limb distal extremity thermal images were taken before propofol administration and at 5-min intervals thereafter during monitored anesthesia. The study enrolled 60 patients with ages ranging from 1.3 to 18 years (mean 10.7 years old) from April 2016 to January 2017. Five minutes following propofol administration, the median temperature differential (delta temperature) between the core and extremity skin significantly decreased in both upper and lower extremities, 7.9 to 3.6 °C (p < 0.0001) and 12.1 to 6.9 °C (p < 0.0001), respectively. By 10 min, the median delta temperatures further decreased significantly in the upper (p = 0.0068) and lower extremities (p = 0.0018). There was a concordant decrease in mean blood pressure (MBP). These trends reverted back when the subject awoke. There was no significant difference between the four operators who used the camera (p = 0.0831). Blood pressure and time temperature change was the only value of significance. Mobil thermal imaging represents a non-invasive modality to assess perfusion in real time. Further studies are required to validate the clinical utility.

Does cryotherapy improve skin circulation compared with compression and elevation in preventing venous leg ulcers?

This trial compared skin blood flow, temperature and incidence of venous leg ulcers in patients with chronic venous disease using compression wraps and elevation pillows. Patients with CEAP C4 skin damage and C5 history of ulcers were randomly assigned to a cryotherapy intervention (n = 138) or placebo cuff control (n = 138) applied to the lower legs over 9 months. The time the ulcers healed prior to enrollment in the study for the cryotherapy group ranged from 1 to 2218 days (n = 8, median = 32 days); for the control group, the range was 24 to 489 days (n = 6, median = 390 days). There were no statistically significant blood flow changes measured in perfusion units with a laser Doppler flowmetre within or between the groups; mean difference between the groups was 0·62, P = 0·619. No differences were noted in skin temperature measured with an infrared thermometer within and between the groups; mean difference between the groups was -0·17°C, P = 0·540. Cryotherapy did not improve skin blood flow or temperature and did not show efficacy in preventing ulcers. However, at least 30% of intervention and 50% of control participants were anticipated to develop an ulcer during the study; only ∼7% occurred. These findings suggest that strict adherence to standard of care decreases the incidence of leg ulcers and remains a best practice for leg ulcer prevention.

Sex differences in symptom severity and clusters in patients with stage C4 and stage C5 chronic venous disease

BACKGROUND

Multiple symptoms associated with chronic venous disease (CVD) are poorly understood, under-recognized, and ill-managed.

AIMS

The aim of this study was to determine whether there are differences in symptoms and symptom clusters between men and women with stage C4 and stage C5 CVD.

METHODS

Data were collected via interviews with 264 patients using a demographic survey and an 11-item VEINES-SYM questionnaire.

ANALYSIS

An intrinsic scoring algorithm was developed to calculate the overall t scores for each item by sex. Exploratory factor analysis identified symptom clusters using oblique rotation to account for correlations between factors.

RESULTS

The average age was 61.7 years; 54.5% of the patients were women, 58% were African American or black, and 60.6% had diabetes. The top three symptoms for women in order of frequency were achy legs, swelling, and pain; for men, these were swelling, achy legs, and heavy legs. For the total group, two symptom clusters emerged: distressful and discomfort. There was no statistically significant difference in factor score between the sexes. Different factor loadings for symptom clusters were observed: women reported hurting and annoying clusters; and men reported nagging and irritating clusters.

CONCLUSION

The data suggest differences in CVD symptoms and clusters by sex. Symptoms in the two clusters were different; however, there was consistency in the factors associated with each cluster. Co-morbid conditions and sex differences in pain responses may play a part in symptom presentation. This study supports the need for increased sex-delineated clinical assessment and consideration of the potential differences between the sexes in the management of CVD symptoms.

Noninvasive imaging technologies for cutaneous wound assessment: A review

The ability to phenotype wounds for the purposes of assessing severity, healing potential and treatment is an important function of evidence-based medicine. A variety of optical technologies are currently in development for noninvasive wound assessment. To varying extents, these optical technologies have the potential to supplement traditional clinical wound evaluation and research, by providing detailed information regarding skin components imperceptible to visual inspection. These assessments are achieved through quantitative optical analysis of tissue characteristics including blood flow, collagen remodeling, hemoglobin content, inflammation, temperature, vascular structure, and water content. Technologies that have, to this date, been applied to wound assessment include: near infrared imaging, thermal imaging, optical coherence tomography, orthogonal polarization spectral imaging, fluorescence imaging, laser Doppler imaging, microscopy, spatial frequency domain imaging, photoacoustic detection, and spectral/hyperspectral imaging. We present a review of the technologies in use or development for these purposes with three aims: (1) providing basic explanations of imaging technology concepts, (2) reviewing the wound imaging literature, and (3) providing insight into areas for further application and exploration. Noninvasive imaging is a promising advancement in wound assessment and all technologies require further validation.

Impact of daily cooling treatment on skin inflammation in patients with chronic venous disease

People with chronic venous disease are at high risk for developing venous leg ulcers. Inflammation is posited as a pathological factor for this chronic condition as evidenced by persistently elevated skin temperature. As part of a larger trial to test the effects of a cooling regimen on leg ulcer prevention, the objective of this preliminary study was to evaluate the first 30 days of intense daily cooling. Compared to a placebo control cuff, a gel cuff applied to the most severely affected lower leg skin for 30 min daily showed no statistically significant differences between temperatures taken in the home at baseline compared to those measured at the 1 month follow up visit. There were also no differences in temperatures noted between the two groups, although the temperatures in the treatment group were lower 30 min after treatment, an indication of adherence. There was no discernable decrease or increase in temperature at a given time point during the 30 day treatment period compared to the control group. It may be better to have patients monitor skin temperature on a daily basis and then apply the cuff as necessary, rather than requiring daily cooling based on baseline measurement. This "prn" approach may provide a sufficient cooling milieu to prevent escalation of inflammation and thwart ulcer occurrence or recurrence. Clinical trials registration #NCT01509599.

Microclimate and development of pressure ulcers and superficial skin changes

This study aims to evaluate the microclimate and development of pressure ulcers and superficial skin changes. A prospective cohort study was conducted in an acute care ward in Indonesia. Risk factors for pressure ulcers and superficial skin changes were identified based on the Bergstrom Braden conceptual model. Microclimate data were collected every 3 days for 15 days while the development of pressure ulcers and superficial skin changes was observed every day. Pressure ulcers and superficial skin changes were developed in 20 of the 71 participants. Total mean difference in skin temperature was higher for patients with pressure ulcers and superficial skin changes (0·9 ± 0·6°C) compared with controls (0·6 ± 0·8°C) (P = 0·071). Binary logistic regression predictor values for pressure ulcers and superficial skin changes were 0·111 for type of sheet and 0·347 for Braden Scale results. In conclusion, difference in skin temperature seems to be a predictor for pressure ulcer development and superficial skin changes, while synthetic fibre sheets are able to maintain a beneficial microclimate.

Comparative study on the effectiveness of myofascial release manual therapy and physical therapy for venous insufficiency in postmenopausal women

OBJECTIVES

Venous insufficiency is present in a large number of postmenopausal women, increasing their risk of disability. The objective of this study was to determine the effects of myofascial release therapy and conventional kinesiotherapy on venous blood circulation, pain and quality of life in postmenopausal patients with venous insufficiency.

METHODS

A randomised controlled trial was undertaken. We enrolled 65 postmenopausal women with stage I or II venous insufficiency on the clinical, aetiological, anatomical and physiopathological (CEAP) scale of venous disorders, randomly assigning them to a control (n=32) or experimental (n=33) group. The control and experimental group patients underwent physical venous return therapy (kinesiotherapy) for a 10-week period, during which the experimental group patients also received 20 sessions of myofascial release therapy. Main outcome measures determined pre- and post-intervention were blood pressure, cell mass, intracellular water, basal metabolism, venous velocity, skin temperature, pain and quality of life.

RESULTS

Basal metabolism (P<0.047), intracellular water (P<0.041), diastolic blood pressure (P<0.046), venous blood flow velocity (P<0.048), pain (P<0.039) and emotional role (P<0.047) were significantly higher in the experimental group than in the control group after the 10-week treatment programme.

CONCLUSION

The combination of myofascial release therapy and kinesiotherapy improves the venous return blood flow, pain and quality of life in postmenopausal women with venous insufficiency.

Skin blood flow response to 2-hour repositioning in long-term care residents: a pilot study

PURPOSE

The purpose of this noninvasive pilot study was to examine the changes in transcutaneous oxygen (tcO2), skin temperature, and hyperemic response in the heels, sacrum, and trochanters in a 2-hour loading-unloading condition in nursing home residents who are positioned in supine and lateral positions.

DESIGN

A 1-group, prospective, repeated-measures design was used.

SUBJECTS AND SETTING

Nine subjects (5 males, 4 females) with a mean age of 85.3 ± 10.86 years (mean ± SD) who required help in turning and positioning at a skilled nursing facility participated in the study.

METHODS

Oxygen and temperature sensors were placed on the heels, trochanters, and sacrum. The subject was (1) positioned lateral for 30 minutes (preload); (2) turned to the supine position with head of the bed at 30° for 2 hours (both sacrum and heels were on the bed surface) (loading); and (3) positioned lateral for 2 hours (unloading). Subjects were turned to either the right or the left side.

RESULTS

Friedman test showed no statistical differences in tcO₂ or skin temperature on the sacrum, heels, or trochanters during preload, supine, and lateral positioning (P > .5). Individual data revealed that hyperemic response was seen in 6 of the 9 subjects when the position was changed from supine to lateral. Only one-third of the subjects attained a sacral tcO₂ of 40 mm Hg or more at the end of the 2-hour lateral positioning. tcO₂ on both heels decreased within the first 30 minutes of loading.

CONCLUSION

Two hours of staying in the supine position lowered sacral oxygenation to less than 40 mm Hg, in some subjects, regardless of whether there was adequate tcO₂ at preload. Repositioning to a lateral position after 2 hours of placement in a supine position did not cause the tcO₂ to return to preload level. The efficacy of a 2-hour repositioning schedule requires further investigation. Since heel tcO₂ was reduced after 30 minutes of loading, further work is needed to determine whether the heels should be offloaded with more frequent repositioning.

The effect of a cryotherapy gel wrap on the microcirculation of skin affected by chronic venous disorders

AIM

The aim of this randomized clinical trial was to investigate a cryotherapy (cooling) gel wrap applied to lower leg skin affected by chronic venous disorders to determine whether therapeutic cooling improves skin microcirculation.

BACKGROUND

Chronic venous disorders are under-recognized vascular health problems that result in severe skin damage and ulcerations of the lower legs. Impaired skin microcirculation contributes to venous leg ulcer development, thus new prevention therapies should address the microcirculation to prevent venous leg ulcers.

METHODS

Sixty participants (n = 30 per group) were randomized to receive one of two daily 30-minute interventions for four weeks. The treatment group applied the cryotherapy gel wrap around the affected lower leg skin, or compression and elevated the legs on a special pillow each evening at bedtime. The standard care group wore compression and elevated the legs only. Laboratory pre- and post-measures included microcirculation measures of skin temperature with a thermistor, blood flow with a laser Doppler flowmeter, and venous refill time with a photoplethysmograph. Data were collected between 2008 2009 and analysed using descriptive statistics, paired t-tests or Wilcoxon signed ranks tests, logistic regression analyses, and mixed model analyses.

RESULTS

Fifty-seven participants (treatment = 28; standard care = 29) completed the study. The mean age was 62 years, 70% female, 50% African American. In the final adjusted model, there was a statistically significant decrease in blood flow between the two groups (-6.2[-11.8; -0.6], P = 0.03). No statistically significant differences were noted in temperature or venous refill time.

CONCLUSION

Study findings suggest that cryotherapy improves blood flow by slowing movement within the microcirculation and thus might potentially provide a therapeutic benefit to prevent leg ulcers.

Agreement and Repeatability of an Infrared Thermometer

Recently, manufacturers have devised thermometers for home use by patients, such as the TempTouch Infrared Thermometer (TTIR; Diabetica Solutions, San Antonio, TX), which is designed with a long handle that can be used for self-monitoring localized skin temperature of the feet and legs. This study assessed the level of agreement and repeatability of the TTIR compared to a thermistor-type thermometer (TT; PeriFlux, 5020 Temperature Unit, Perimed, Stockholm, Sweden), the reference standard. In 17 healthy subjects, localized skin temperature was measured 8 cm above the right medial malleolus at baseline (Time 1), after a 10-minute rest period (Time 2), and after 10 minutes of cold provocation (Time 3) with a cryotherapy gel wrap placed around the lower legs using the TTIR and TT for temperature measurement. Scatter plots and correlation coefficients showed strong positive relationships between the two measurement methods at all three time points (Time 1: r = 0.95; Time 2: r = 0.97; and, Time 3: r = 0.87). Results showed a reasonable level of agreement between the two methods at Times 1 and 2 but not after cold provocation. Agreement between the methods appears to be better than repeatability within each method. Results for repeatability from both the TT and TTIR were very similar suggesting that there was a systematic bias with increasing temperatures between Time 1 and Time 2.

Foot temperature in healthy individuals: effects of ambient temperature and age

BACKGROUND

Patient complaints of excessively warm or cold feet are common in medical practice. Such symptoms can be caused by underlying vascular or neurologic disease, and measurement of foot temperature during daily activity and sleep could provide a deeper understanding of their actual thermal basis.

METHODS

We used a Thermochron iButton to assess surface foot temperature variation and its relationship to ambient temperature during the day with activity and at night during sleep in 39 healthy individuals aged 18 to 65 years in a temperate region of the United States. We simultaneously used actigraphy to record leg movement.

RESULTS

We identified a mean +/- SD awake temperature of 30.6 degrees +/- 2.6 degrees C and asleep temperature of 34.0 degrees +/- 1.8 degrees C, with values reaching as low as 15.9 degrees C in the winter and as high as 37.5 degrees C in the summer. Foot temperature was found to be independent of foot movement or sex; however, there was, as expected, a strong association between foot temperature and ambient temperature (r = .59, P < .001). Several measures of foot temperature variation demonstrated a significant or near-significant reduction with increasing age, including the Euclidean distance (r = -.38, P = .02) for awake periods and the variance (r = -.30, P = .06) during sleep.

CONCLUSIONS

These results provide data on the normal variation of foot temperature in individuals living in a temperate climate and demonstrate the potential use of Thermochron iButton technology in clinical contexts, including the evaluation of patients with excessively warm or cold feet.

Recruitment strategy effectiveness for a cryotherapy intervention for a venous leg ulcer prevention study

PURPOSE

To describe the strategies and costs associated with recruiting African American and white adults into a randomized controlled pilot trial.

DESIGN

"Cryotherapy for Venous Disorders: A Pilot Study" is a randomized controlled trial designed to determine the effects of a cool gel wrap and leg elevation intervention versus a leg elevation alone intervention on skin temperature, skin microcirculation, quality of life, and pain in adults with stages 4 and 5 chronic venous disorders. We sought to recruit 60 participants (21 African Americans, 37 whites, and 2 Hispanic or Latino) to complete the study. These enrollment targets reflect the demographic distribution of the community in which the study was conducted (33% African American, 66% white, and 2% Latino). Proactive and reactive recruitment strategies were implemented to recruit subjects.

RESULTS

Seventy-three individuals (9 African American men, 29 African American women, 11 white men, 22 white women, 1 Asian woman, and 1 Hispanic woman) were screened, and of those, 67 were randomized (9 African American men, 25 African American women, 9 white men, 22 white women, 1 Asian woman, and 1 Hispanic women). Fifty-eight completed the study, yielding an overall 11% attrition rate. An additional 8 subjects canceled or did not show up for a first appointment. Reactive recruitment strategies were most successful for recruiting men, women, African American, and white participants. The 3 most successful reactive strategies were referrals from providers/clinics (34%), flyers posted in the hospital elevators (22%), and targeted mailings from a business (16%). Of the healthcare provider referrals (19), wound care nurses referred 12 completed participants. The amount budgeted for advertisement was $5,000 (2% of the total grant award). The amount spent on recruitment including labor was $5,978, which averaged $103 per participant who completed the study (N = 58). Reactive strategies per participant completer proved more cost-efficient than proactive strategies ($83 vs $215). However, the time spent by the principal investigator (approximately 100 hours or 2.5 hours per week x 40 weeks) on recruitment, particularly maintaining frequent face-to-face contact with providers, increased success in the area of healthcare provider referrals.

CONCLUSION

A variety of recruitment strategies are needed to ensure a diverse participant response to clinical research studies. As nurses become more involved in research activities, and particularly in recruitment, it is important to understand the most effective types of strategies and costs associated with these activities.

Skin perfusion pressure in chronic venous disorders

OBJECTIVE

To examine whether a patient group with chronic venous disorders (CVDs) would show a different response to a pressure provocation test, such as skin perfusion pressure (SPP) of microcirculatory function.

DESIGN

A cuff inflation technique was applied to the gaiter area of the lower legs to induce complete occlusion of the microcirculation. The cuff was then released to measure the pressure at which perfusion resumed, and SPP was measured with a laser Doppler flowmeter (LDF). The measurements at reperfusion were taken of skin of the lower legs of individuals with CVD and compared with the lower-leg skin of control participants.

MAIN OUTCOME MEASURES

To establish whether a measurable difference in SPP exists between the group with CVD and the group without CVD, the means of 9 measurements taken were compared using the Student t test. The lowest value of the 9 measurements of minimum pressure (LMV) was used to estimate the pressure at which reperfusion occurred (SPP). The means of those estimates were then compared using the Student t test.

MAIN RESULTS

The mean LMV measured in the CVD group was slightly higher than that measured in the group without CVD. Although this could be considered a clinically significant result, it was not statistically different.

CONCLUSIONS

For this study, SPP was not significantly different for those with CVD compared with those without. These results suggest that SPP conducted with an LDF has little potential to detect "invisible" changes in the microcirculatory function of the skin affected by CVDs.

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.

Sudden increase in skin temperature predicts venous ulcers: a case study

Venous ulcers affect approximately 2.5 million adults with chronic venous disease (CVD). Venous ulcers are a significant health problem with a reoccurrence rate as high as 72%. There is a critical need for a prediction/prevention model of venous ulcers that includes objective methods to assess the skin. Among individuals affected by CVD, skin temperature is elevated in the lower extremities. This case study of a patient with CVD highlights the potential predictive usefulness and feasibility of measuring skin temperature with an infrared dermal thermometer as part of the standard of care for venous ulcer prevention.