Adjustable compression wraps: stretch, interface pressures and static stiffness indices.

Simultaneous Changes of Leg Circumference and Interface Pressure Under Different Compression Bandages

The objectives of the current study were to compare intra-socket pressure differences between comfortable and uncomfortable socket conditions, and the usefulness of subject perception of satisfaction, activity limitations, and socket comfort in distinguishing between these two socket conditions. Five unilateral trans-tibial amputees took part in the study. They answered the Socket Comfort Score (SCS) and Trinity Amputation and Prosthetic Experience Scale (TAPES) questionnaires before the interface pressure (in standing and walking) was measured for the uncomfortable socket condition at five regions of the residual limb. Participants were then provided with a comfortable socket and wore it for two weeks. Participants who were satisfied with the socket fit after two weeks repeated the SCS and TAPES questionnaires and interface pressure measurements. The differences between the test results of the two conditions were not statistically significant, except for the interface pressure at the popliteal region during the early stance phase, TAPES socket fit subscale, and the SCS. Due to large variability of the data and the lack of statistical significance, no firm conclusion can be made on the possible relationship between the interface pressure values and the patient-reported outcomes of the two socket conditions. A larger sample size and longer acclimation period are required to locate significant differences.

Measuring interface pressure (IP) is one way to characterize cushion performance in the clinic and laboratory. This study explored how the presence of four commercially available IP mats affected IP on and immersion of two buttocks models. We loaded seven cushions with each buttocks model and captured pressure data using FSA sensors (Vista Medical Ltd; Winnipeg, Manitoba, Canada). Analysis was performed to compare pressure magnitude and immersion. Overall, both pressure magnitude and immersion changed after mat introduction. A significant interaction existed between cushion and mat condition and cushion and model for all variables. Introducing an IP mat to the model-cushion interface alters the loading on the cushion. The mats bridged the contours of the model, causing a change in IP at the locations studied. Although immersion was statistically different between mat conditions, the magnitude of the difference was less than 1 mm once we accounted for the thickness of the mats. The significance of the cushion-mat interaction indicates that the mat effect differed across cushion design. Clinical and research users of pressure mats should consider the effect of mat presence, the effect of model design, and mat and buttocks interactions with cushions for successful use.

Previous research shows that maximum interface pressure increases when the patient is lying in the lateral position. However, it was unclear whether it was better to increase or decrease the internal air pressure to reduce the maximum interface pressure in the lateral position; thus, this study investigated this issue. In this study, we investigated the change in pressure redistribution because of the difference in internal air pressure between the supine and lateral positions on an active air mattress for pressure ulcer prevention management. Each participant's five internal air pressure values served as the independent variables. The interface pressure on the active air mattress was measured for 20 minutes. The sacral left iliac crest and left greater trochanteric interface pressures were measured using a portable pressure‐measuring device. When seven of the 10 participants switched from the supine position to the left lateral position, there was a decrease in the maximum interface pressure as the internal air pressure increased. The maximum interface pressure in the greater trochanter in the lateral position was twice that in the sacral region in the supine position. These results show that increasing the internal air pressure in the lateral position might help reduce the maximum interface pressure.

To evaluate the interface pressures (IP) obtained by double compression stockings. Ten healthy volunteers with legs fitting size S stockings wore single and double class I stockings, sizes S to 4L. We measured IPs with the patient wearing each stocking standing and supine. IPs obtained wearing double S size stockings, standing and supine, were 1.7 times and 20 mmHg higher than those obtained by a single S size stocking (52.1 ± 4.7 and 46.4 ± 4.5 mmHg vs. 31.5 ± 3.3 and 27.3 ± 2.3 mmHg, respectively). Despite the decreasing IP with increased stocking sizes, all IPs obtained by double stockings, standing and supine, even with size 4L (43.2 ± 5.1 and 37.3 ± 5.5 mmHg respectively), were significantly higher than those obtained by a single S stocking. Significantly higher IPs were achieved standing and supine, by doubling stockings. We should rather be aware that double stockings in the supine position can result in excessively high IPs.

Increased elevation of the head of the bed is linked to a higher risk for sacral pressure ulcers. A semirecumbent position of at least 30° is recommended for the prevention of ventilator-associated pneumonia in patients treated with mechanical ventilation. Therefore, prevention of pressure ulcers and prevention of pneumonia seem to demand contradictory, possibly incompatible, positioning. To measure pressure at the interface between sacral skin and the supporting surface in healthy volunteers at different degrees of upright position with different types of mattresses. An open, prospective, randomized crossover trial was conducted with 20 healthy volunteers. Interface pressure was measured by using a pressure mapping device with the participant in a supine position at 0, 10°, 30°, and 45° elevation and in the reverse Trendelenburg position at 10° and 30°. Four types of mattresses were examined: 2 different foam mattresses and 2 air suspension beds, 1 of the latter with low-air-loss technology. Peak sacral interface pressures increased significantly only at 45° of backrest elevation (P < .001). A mattress system with low-air-loss technology significantly reduced peak interface pressures at all angles (P < .001). The reverse Trendelenburg position led to lower peak pressures for all positions (P = .01). Backrest elevation up to 30° might be a compromise between the seemingly incompatible demands of skin integrity and the prevention of ventilator-associated pneumonia. The reverse Trendelenburg position and a mattress system with low-air-loss technology could be additional useful tools to help prevent skin breakdown at the sacrum.

Background: Compression is a cornerstone modality in edema treatment. Different types of bandages are available in clinical practice. Short-stretch bandages are commonly used; however, newer technologies such as the two-component compression system are available as well. This study assesses the pressure curves and static and dynamic stiffness (Static Stiffness Index [SSI] and Dynamic Stiffness Index [DSI]) of two different two-component compression systems, Coban and CoFlex, for edema treatment. Methods and Results: For this prospective cohort study, 12 healthy volunteers were recruited. The healthy volunteers wore both two-component compression systems for 48 hours. Pressure sensors (PicoPress®; Microlab, Italy) were placed at 10 and 25 cm above the internal malleolus and 10 pressure readings were used to obtain pressure curves. The SSI and DSI were assessed. Additionally, comfort (ICC compression questionnaire) and adverse events were assessed as well. Both two-component compression systems exert a sufficient amount of sub-bandage pressure, although CoFlex exerts systematically significantly lower pressure in comparison with Coban. This difference in sub-bandage pressure remains constant over 48 hours. Both two-component compression systems are sufficiently stiff (stiffness >15 mmHg) and remain stiff over time. Conclusions: Both two-component compression systems have pressure curves that are high enough to motivate their use in the treatment of chronic edema. Additionally, both systems were found to be comfortable and have clinically effective SSI and DSI values.

In the Ultrasonic Waves Method for Interface Pressure Measurement (UWM in Sound Pressure Domain), the characteristic features as the engineering problem differ considerably from those in other engineering problems. In the joint of dry condition, the measuring principle of UWM is based on the synergy effect of the joint elastic deflection and sound reflection characteristics at the joint surface. As a result, the performance of UWM depends largely upon the definition of the interface pressure for which we used to deal with the nominal interface pressure without any doubt so far. It is however emphasised that the interface pressure is one of uncertain attributes when considering the mechanism of Two Bodies-in-Contact as per the Theory of Bowden and Tabor. To be aware of such an important fact, thus, the present perspective of UWM will be especially described in this chapter after reviewing other measuring methods for the interface pressure. For further convenience, some applications of UWM to the industrial product will be also noted.

Repositioning patients regularly to prevent pressure ulcers and reduce interface pressures is the standard of care, yet prior work has found that standard repositioning does not relieve all areas of at-risk tissue in nondisabled subjects. To determine whether this holds true for high-risk patients, we assessed the effectiveness of routine repositioning in relieving at-risk tissue of the perisacral area using interface pressure mapping. Bedridden patients at risk for pressure ulcer formation (n = 23, Braden score <18) had their perisacral skin-bed interface pressures recorded every 30 s while they received routine repositioning care for 4-6 h. All participants had specific skin areas (206 +/- 182 cm(2)) that exceeded elevated pressure thresholds for >95% of the observation period. Thirteen participants were observed in three distinct positions (supine, turned left, turned right), and all had specific skin areas (166 +/- 184 cm(2)) that exceeded pressure thresholds for >95% of the observation period. At-risk patients have skin areas that are likely always at risk throughout their hospital stay despite repositioning. Healthcare providers are unaware of the actual tissue-relieving effectiveness (or lack thereof) of their repositioning interventions, which may partially explain why pressure ulcer mitigation strategies are not always successful. Relieving at-risk tissue is a necessary part of pressure ulcer prevention, but the repositioning practice itself needs improvement.

Occupational therapists are often involved in assessing the seating needs of clients who have quadriplegia. One component of this process involves determining the appropriate use of wheelchair cushions and pressure relieving techniques in the prevention of pressure sores. The purpose of this study was to assess the effect of tilt and recline positioning and various wheelchair cushions on interface pressures at the ischial tuberosities and the sacrum of two subjects with C5 quadriplegia. In addition, interface pressures under bony prominences were assessed in the personal driving position (when the subject enters), neutral, 35 degree tilt, 45 degree tilt, and maximum recline (150 degrees). The results of this study indicate that for the two subjects evaluated, higher average interface pressures at the ischial tuberosities were obtained when using one of the three cushions under scrutiny. Furthermore, the general trend observed with both subjects is a reduction of pressure readings at the ischial tuberosities with tilt and recline positioning (especially with 45 degree tilt and 150 degree recline). The findings of this study are in keeping with previous studies which identified that individual and ongoing assessment is essential in providing the best cushion and pressure relief techniques for individuals.

The importance of measuring interface pressure and stiffness to characterize the elastic properties of materials has been stressed with regard to elastic stockings and elastic bandages. The objective of this study was to compare the pressure profiles of nine different elastic stockings and to quantify the effects of posture changes and exercise on compression. Using a pressure transducer (Air Pack Type Analyzer), the interface pressure associated with nine different elastic stockings was measured at level B1 during supine resting, standing, and exercise. The elastic stockings examined could be divided into two categories according to extensibility: short stretch (< 105% extensibility) and long stretch (> 105% extensibility). Short-stretch stockings include thick round-knitted stockings, firm round-knitted stockings, and flat-knitted stockings. Short-stretch stockings showed a higher peak working pressure and a larger pressure amplitude during exercise than long-stretch stockings. Short-stretch stockings can be expected to have more pronounced benefits for augmenting muscle pumping in the same way as short-stretch bandages. In selecting suitable elastic stockings for patients, the stiffness should be taken into account in addition to interface pressure.

Background: Lymphedema is a chronic and progressive disease whose diagnosis involves determination of clinical and demographic characteristics. The aim of this retrospective study was to analyze the clinical characteristics of patients with lymphedema and their various diagnoses. We studied patients who were referred for physiotherapy services at any point during the years 2009 through 2019. Methods: Retrospective data were collected from the files of 430 lymphedema patients. The type, cause, localization, stage, and severity of lymphedema and physiotherapy needs were analyzed and reported. Results: Primary and secondary lymphedema were observed in 18 (4.2%) and 412 (95.8%) patients, respectively. The patients' mean body mass index score was 30.66 kg/m2. The data indicated that the most common cause of secondary lymphedema was breast cancer and its treatments (n = 196, 47.6%). Other causes were chronic venous insufficiency (CVI) (n = 140, 34%), lipolymphedema (n = 11, 2.7%), and other types of cancers (n = 65, 15.7%). According to the affected body regions, 416 patients had unilateral/bilateral upper and lower extremity lymphedema and 14 had head and neck lymphedema. The patients were followed with a home-based physiotherapy program (n = 353, 82.1%) or they underwent treatments through an outpatient program (n = 77, 17.9%). Conclusions: Most patients admitted to the clinic had a diagnosis of breast cancer and CVI. The severity and stages of lymphedema were variable. The data indicated that most patients were followed through a home-based physiotherapy program. These results may set a frame for understanding the treatment and care needs of patients with lymphedema.

The aim of the study was to compare the degree of pressure created when healthy adult volunteers sat on a hospital recliner chair in various positions and on various cushions. Comparative cross-sectional study. Thirty-four healthy subjects were recruited from the community, an urban city in a rural area of Eastern North Carolina. Interface pressure measurements were taken by the investigators for each subject sitting on a standard hospital recliner under each of the following conditions: no cushion, foam cushion, nonadjustable air cushion, nonadjustable air/foam cushion, and adjustable air cushion. Subject positions, upright sitting and reclined, were randomly selected. Analyses consisted of data visualizations by investigators and univariate statistics. For each surface, mean pressure, peak pressure, and Pressure Area Index (PAI) were obtained and compared. Inferences were drawn from a repeated-measures analysis-of-covariance model. Subject position was not associated with any of the measures for each surface after adjusting for other variables (average pressure P = .1094, maximum/peak pressure P = .1318, PAI P = .4336). Subject weight, the type of surface, and their interaction do impact the results (average pressure, maximum/peak pressure, and PAI, P < .0001). The foam cushion had the highest mean and average interface pressures and the lowest PAI. The nonadjustable air and air/foam cushions performed most similarly to each other, showing lowest mean and average interface pressures and the highest PAI. Position of a hospital recliner chair in the 2 positions studied had no association with interface pressure outcomes; therefore, other methods of pressure redistribution need to be utilized by clinicians. Based on the results of this study, clinicians may need to reevaluate the type of cushion used in the acute hospital setting, as a standard foam cushion was found to increase interface pressures when compared to other cushions and a standard hospital recliner.

The aim of this work was to evaluate the short-term fractal index (α1 ) of heart rate variability (HRV) in chronic renal failure (CRF) patients by identifying the effects of orthostatism and hemodialysis (HD), and by evaluating the correlation between α1 and the mean RR interval from sinus beats (meanNN). HRV time series were derived from ECG data of 19 CRF patients and 20 age-matched healthy subjects obtained at supine and orthostatic positions (lasting 5 min each). Data from CRF patients were collected before and after HD. α1 was calculated from each time series and compared by analysis of variance. Pearson's correlations between meanNN and α1 were calculated using the data from both positions by considering three groups: healthy subjects, CRF before HD and CRF after HD. At supine position, α1 of CRF patients after HD (1.17 ± 0.30) was larger (P < 0.05) than in healthy subjects (0.89 ± 0.28) but not before HD (1.10 ± 0.34). α1 increased (P < 0.05) in response to orthostatism in healthy subjects (1.29 ± 0.26) and CRF patients after HD (1.34 ± 0.31), but not before HD (1.25 ± 0.37). Whereas α1 was correlated (P < 0.05) with the meanNN of healthy subjects (r = -0.562) and CRF patients after HD (r = -0.388), no significance in CRF patients before HD was identified (r = 0.003). Multiple regression analysis confirmed that α1 was mainly predicted by the orthostatic position (in all groups) and meanNN (healthy subjects and patients after HD), showing no association with the renal disease condition in itself. In conclusion, as in healthy subjects, α1 of CRF patients correlates with meanNN after HD (indicating a more irregular-like HRV behavior at slower heart rates). This suggests that CRF patients with stable blood pressure preserve a regulatory adaptability despite a shifted setting point of the heart period (i.e., higher heart rate) in comparison with healthy subjects.

To investigate the clinical practicability of positive end-expiratory pressure (PEEP) titrated by lung stretch index (SI) in patients with acute respiratory distress syndrome (ARDS). A parallel randomized controlled trial was conducted. Patients with moderate to severe ARDS who required mechanical ventilation admitted to the department of critical care medicine of General Hospital of the Yangtze River Shipping from August 2022 to February 2023 were enrolled. They were randomly divide into SI guided PEEP titration group (SI group) and pressure-volume curve (P-V curve) inspiratory low inflection point (LIP) guided PEEP titration group (LIP group). All patients were ventilated in a supine position after admission, with the head of the bed raised by 30 degree angle. The primary disease was actively treated, prone position ventilation for 12 h/d, and lung protective ventilation strategies such as controlled lung expansion were used for lung recruitment. On this basis, mechanical ventilation parameters were titrated with SI in the SI group; the LIP group titrated mechanical ventilation parameters with P-V curve inspiratory LIP+2 cmH2O (1 cmH2O≈0.098 kPa). The oxygenation index (PaO2/FiO2), and respiratory mechanics indicators such as lung dynamic compliance (Cdyn), peak airway pressure (Pip) were monitored before recruitment maneuver and after 1, 3, and 5 days of treatment. The therapeutic effect of the two groups was compared. There were 41 patients in the SI group and 40 patients in the LIP group. There was no significant difference in general information such as gender, age, and disease type between the two groups. The mechanical ventilation time and the length of intensive care unit (ICU) stay in the SI group were significantly shorter than those in the LIP group (days: 9.47±3.36 vs. 14.68±5.52, 22.27±4.68 vs. 27.57±9.52, both P < 0.05). Although the 28-day mortality of the SI group was lower than that of the LIP group, the difference was not statistically significant [19.5% (8/41) vs. 35.0% (14/40), P > 0.05]. On the fifth day, the PaO2/FiO2 was higher in SI group [mmHg (1 mmHg≈0.133 kPa): 225.57±47.85 vs. 198.32±31.59, P < 0.05], the Cdyn was higher in SI group (mL/cmH2O: 47.39±6.71 vs. 35.88±5.35, P < 0.01), the Pip was lower in SI group (mmHg: 35.85±5.77 vs. 43.87±6.68, P < 0.05). The Kaplan-Meier survival curve showed no statistically significant difference in the 28 days cumulative survival rate between the two groups (Log-Rank: χ 2 = 2.348, P = 0.125). The application of SI titration with PEEP in the treatment of ARDS patients may improve their prognosis.