Cuff Width Research Articles

Body position and cuff size influence lower limb arterial occlusion pressure and its predictors: implications for standardizing the pressure applied in training with blood flow restriction.

Background: Arterial occlusion pressure (AOP) is a relevant measurement for individualized prescription of exercise with blood flow restriction (BFRE). Therefore, it is important to consider factors that may influence this measure. Purpose: This study aimed to compare lower limb AOP (LL-AOP) measured with 11cm (medium) and 18cm (large) cuffs, in different body positions, and explore the predictors for each of the LL-AOP measurements performed. This information may be useful for future studies that seek to develop approaches to improve the standardization of pressure adopted in BFRE, including proposals for equations to estimate LL-AOP. Methods: This is a cross-sectional study. Fifty-one healthy volunteers (males, n = 25, females, n = 26; Age: 18-40years old) underwent measurement of thigh circumference (TC), brachial blood pressure, followed by assessments of LL-AOP with medium and large cuffs in positions supine, sitting and standing positions. Results: The large cuff required less external pressure (mmHg) to elicit arterial occlusion in all three-body positions when compared to the medium cuff (p < 0.001). The LL-AOP was significantly lower in the supine position, regardless of the cuff used (p < 0.001). Systolic blood pressure was the main predictor of LL-AOP in the large cuff, while TC was the main predictor of LL-AOP with the medium cuff. Body position influenced strength of the LL-AOP predictors. Conclusion: Our results indicate that LL-AOP and its predictors are substantially influenced by body position and cuff width. Therefore, these variables should be considered when standardizing the pressure prescribed in BFRE.

Acute physiological responses of blood flow restriction between high-intensity interval repetitions in trained cyclists.

Blood flow restriction (BFR) is increasingly being used to enhance aerobic performance in endurance athletes. This study examined physiological responses to BFR applied in recovery phases within a high-intensity interval training (HIIT) session in trained cyclists. Eleven competitive road cyclists (mean±SD, age: 28±7years, body mass: 69±6kg, peak oxygen uptake: 65±9mL ·kg-1· min-1) completed two randomised crossover conditions: HIIT with (BFR) and without (CON) BFR applied during recovery phases. HIIT consisted of six 30-s cycling bouts at an intensity equivalent to 85% of maximal 30-s power (523±93W), interspersed with 4.5-min recovery. BFR (200mmHg, 12cm cuff width) was applied for 2-min in the early recovery phase between each interval. Pulmonary gas exchange (V̇O2, V̇CO2, and V̇E), tissue oxygen saturation index (TSI), heart rate (HR), and serum vascular endothelial growth factor concentration (VEGF) were measured. Compared to CON, BFR increased V̇CO2 and V̇E during work bouts (both p<0.05, dz<0.5), but there was no effect on V̇O2, TSI, or HR (p>0.05). In early recovery, BFR decreased TSI, V̇O2, V̇CO2, and V̇E (all p<0.05, dz>0.8) versus CON, with no change in HR (p>0.05). In late recovery, when BFR was released, V̇O2, V̇CO2, V̇E, and HR increased, but TSI decreased versus CON (all p<0.05, dz>0.8). There was a greater increase in VEGF at 3-h post-exercise in BFR compared to CON (p<0.05, dz>0.8). Incorporating BFR into HIIT recovery phases altered physiological responses compared to exercise alone.

Blood flow restriction pressure for narrow cuffs (5 cm) cannot be estimated with precision.

Blood flow restriction pressures are set relative to the lowest pressure needed to occlude blood flow with that specific cuff. Due to pressure limitations of some devices, it is often not possible to occlude blood flow in all subjects and apply a known relative pressure in the lower body with a 5 cm wide cuff.Objective. To use a device capable of generating high pressures (up to 907 mmHg) to create and validate an estimation equation for the 5 cm cuff in the lower body using a 12 cm cuff.Approach. 170 participants had their arterial occlusion pressure (AOP) with a 5 cm and 12 cm cuff and their thigh circumference measured in their right leg. The sample was randomly allocated to a prediction group (66%) and validation group (33%). Thigh circumference and 12 cm AOP were used as predictors. A Bland-Altman plot was constructed to assess agreement between measured and predicted values.Main results. The mean difference (95% confidence interval) between the observed (336.8 mmHg) and the predicted (343.9 mmHg) 5 cm AOP was 7.1 (-11.9, 26.1) mmHg. The 95% limits of agreement were -133.6 to 147.8 mmHg. There was a negative relationship between the difference and the average of predicted and measured 5 cm AOP (B= -0.317,p= 0.000043).Significance. Although this was the first study to quantify AOP over 600 mmHg with a 5 cm cuff, our equation is not valid across all levels of pressure. If possible, larger cuff widths should be employed in the lower body.

Influence of cuff stiffness on hemodynamics and perceived cuff pressure in the upper extremities in males and females: implications for practical blood flow restriction training

BackgroundPractical blood flow restriction (pBFR) during exercise is a cost-saving alternative to traditional blood flow restriction using pneumatic cuffs, particularly when exercising in a group setting. Depending on the pBFR technique, several factors (e.g., cuff width, limb circumference) have already been shown to be of importance when applying the pBFR pressure. Given that elastic cuffs are often used for pBFR, the cuff stiffness might be an additional influencing factor. Therefore, the present study compared the acute effects of three elastic cuffs with identical width but different stiffness (high stiffness (HS), medium stiffness (MS), and low stiffness (LS)) on hemodynamic measures and perceived cuff pressure at rest.MethodsIn a randomized, counter-balanced cross-over study, 36 young and normotensive participants completed three experimental trials. After a 10-min rest period in supine position, the cuff was loosely and proximally applied to the right upper arm. Following baseline data recording, the cuff was successively tightened in 10%-increments with respect to the limb circumference (%overlap) until arterial blood flow was occluded. At baseline and during each %overlap, systolic peak blood flow velocity of the brachial artery, rating of perceived cuff pressure, as well as muscle oxygen saturation and total hemoglobin concentration of the biceps brachii muscle were recorded.ResultsThe %overlap required to occlude arterial blood flow was different between the three cuffs (HS: 30.9 ± 3.8%, MS: 43.9 ± 6.1%, LS: 54.5 ± 8.3%). Furthermore, at 30% overlap, systolic peak blood flow velocity was lower when applying the HS (9.0 ± 10.9 cm∙s− 1) compared to MS (48.9 ± 21.9 cm∙s− 1) and LS cuff (62.9 ± 19.1 cm∙s− 1). Rating of perceived cuff pressure at 30% overlap was higher when using the HS (6.5 ± 1.5 arbitrary unit (a.u.)) compared to MS (5.1 ± 1.4 a.u.) and LS cuff (4.9 ± 1.5 a.u.) with no difference between the MS and LS cuff. However, muscle oxygen saturation and total hemoglobin concentration were not different between the three cuffs.ConclusionsThe present study revealed that the cuff stiffness influenced blood flow velocity and arterial occlusion pressure. Therefore, cuff stiffness seems an important factor for the application of pBFR.

Predictors of Arterial Occlusion Pressure in the Lower-Body Across Commonly Used Cuff Widths

For implementation of exercise with blood flow restriction (BFR), cuff pressures should be based on arterial occlusion pressure (AOP). Limb circumference and blood pressure have been identified as predictors of AOP and used to set appropriate exercising cuff pressures. However, it is unclear whether these predictors are consistent across BFR cuffs of varying width. Our purpose was to compare predictors of lower-body AOP in a variety of commonly utilized cuff widths. We hypothesized that limb circumference would be a stronger predictor when using narrower cuffs while blood pressure would be a stronger predictor when using wider cuffs.Healthy normotensive adults (women=44, men=76; age:23±4yrs; BMI:25±4) underwent measurements of thigh circumference (TC) and systolic (SBP) and diastolic blood pressure (DBP). Lower-body AOP was assessed (via Doppler ultrasound) in the post-tibial artery in a seated position with an 11, 13, and 18cm wide pneumatic cuff. Models of hierarchical linear regression were constructed to predict AOP in each of the cuffs using TC, SBP, and DBP as predictor variables. A linear mixed effects model including AOP as the outcome variable was fit. The model included fixed effects of TC, SBP, DBP, cuff width, TC x cuff width, SBP x cuff width, and DBP x cuff width, and a random intercept for participants.AOP was 188±28, 170±20, and 152±15mmHg, for the 11, 13, and 18cm cuff, respectively. For the 11cm cuff, TC (β = 0.66, part = 3.46), SBP (β = 0.17, part = 0.48), and DBP (β = 0.21, part = 3.46) were significant predictors that explained 74% of AOP variability. For the 13cm cuff, TC (β = 0.56, part = 2.06), SBP (β = 0.25, part = 0.48), and DBP (β = 0.22, part = 0.59) were significant predictors that explained 69% of AOP variability. In the 18cm cuff, TC (β = 0.35, part = 0.10) and SBP (β = 0.48, part = 0.72) were significant predictors that explained 57% of the AOP variability. There were significant main effects of TC, SBP, DBP, and cuff width on AOP, and significant interactions of TC x cuff width and SBP x cuff width (all P&lt;0.05). Results indicated that when using a narrow cuff, AOP was largely based on TC and when using a wider cuff, AOP was based mostly on SBP. Differences are likely due to wider cuffs transmitting pressures more efficiently into underlying soft tissues, thereby reducing the influence of TC on AOP and shifting greater influence towards blood pressure. Our results support and expand on previous work in a small sample (n=12) reporting that AOP depends more on TC as cuff width decreases. Together, these data provide evidence that cuff width should be considered when selecting factors to estimate AOP and establish appropriate pressures during lower-body BFR exercise. This work was supported by the Michigan Tech Health Research Institute This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Blood Flow Restriction Training in Clinical Rehabilitation: Occlusion Pressure Methods Relative to the Limb Occlusion Pressure.

Resistance training with blood flow restriction (BFR) has increased in clinical rehabilitation due to the substantial benefits observed in augmenting muscle mass and strength using low loads. However, there is a great variability of training pressures for clinical populations as well as methods to estimate it. The aim of this study was to estimate the percentage of maximal BFR that could result by applying different methodologies based on arbitrary or individual occlusion levels using a cuff width between 9 and 13cm. A secondary analysis was performed on the combined databases of 2 previous larger studies using BFR training. To estimate these percentages, the occlusion values needed to reach complete BFR (100% limb occlusion pressure [LOP]) were estimated by Doppler ultrasound. Seventy-five participants (age 24.32 [4.86]y; weight: 78.51 [14.74]kg; height: 1.77 [0.09]m) were enrolled in the laboratory study for measuring LOP in the thigh, arm, or calf. When arbitrary values of restriction are applied, a supra-occlusive LOP between 120% and 190% LOP may result. Furthermore, the application of 130% resting brachial systolic blood pressure creates a similar occlusive stimulus as 100% LOP. Methods using 100mm Hg and the resting brachial systolic blood pressure could represent the safest application prescriptions as they resulted in applied pressures between 60% and 80% LOP. One hundred thirty percent of the resting brachial systolic blood pressure could be used to indirectly estimate 100% LOP at cuff widths between 9 and 13cm. Finally, methodologies that use standard values of 200 and, 300mm Hg far exceed LOP and may carry additional risk during BFR exercise.

Beneath the cuff: Often overlooked and under-reported blood flow restriction device features and their potential impact on practice-A review of the current state of the research.

Training with blood flow restriction (BFR) has been shown to be a useful technique to improve muscle hypertrophy, muscle strength and a host of other physiological benefits in both healthy and clinical populations using low intensities [20%-30% 1-repetition maximum (1RM) or <50% maximum oxygen uptake (VO2max)]. However, as BFR training is gaining popularity in both practice and research, there is a lack of awareness for potentially important design characteristics and features associated with BFR cuff application that may impact the acute and longitudinal responses to training as well as the safety profile of BFR exercise. While cuff width and cuff material have been somewhat addressed in the literature, other cuff design and features have received less attention. This manuscript highlights additional cuff design and features and hypothesizes on their potential to impact the response and safety profile of BFR. Features including the presence of autoregulation during exercise, the type of bladder system used, the shape of the cuff, the set pressure versus the interface pressure, and the bladder length will be addressed as these variables have the potential to alter the responses to BFR training. As more devices enter the marketplace for consumer purchase, investigations specifically looking at their impact is warranted. We propose numerous avenues for future research to help shape the practice of BFR that may ultimately enhance efficacy and safety using a variety of BFR technologies.

Cuff width does not affect discomfort ratings immediately following isometric handgrip exercise

AbstractPrevious work has found that wide cuffs produce greater discomfort with elbow flexion exercise than narrower cuffs. It is our hypothesis that this is due to the balling up of the biceps underneath the cuff that is more pronounced with a wider cuff. One method to test this is through an upper body exercise where there is no contraction of the biceps.PurposeTo investigate the effects of cuff width on discomfort following isometric handgrip exercise.MethodsOne hundred participants completed this experiment. In a randomized order, the participants performed four sets of two-minute isometric handgrip contractions with thirty seconds of rest at thirty percent of their maximal voluntary contraction with a 5 and 12 cm cuff inflated to 40% of arterial occlusion pressure. Discomfort ratings (0–100) were given after the fourth set of exercise. Average force was recorded for all four sets.ResultsThere was no difference in discomfort (BF10 = 0.158) [median difference (95% credible interval) −0.997 (−3.360, 1.283) arbitrary units], or in average force (BF10 = 0.132) [median difference (95% credible interval) 0.08 (−0.199, 0.372) kilograms], between cuff conditions. There did not appear to be a greater preference for either cuff. Forty people preferred the narrow cuff (BF10 = 0.325), forty people preferred the wide cuff (BF10 = 0.325), and twenty people had no preference (BF10 = 7.719).ConclusionCuff width does not appear to influence discomfort or the average force produced. This provides support for our hypothesis that the shape of the muscle may interact with wider cuff sizes, leading to greater discomfort.

Relationship between rotator cuff posterior delamination and subscapularis tear: a large cross-sectional analysis

Rotator cuff posterior delamination and subscapularis tear are commonly observed in rotator cuff injuries. However, there are very few studies on the relationship between posterior delamination and subscapularis tendon tear. This study aimed to investigate the relationship between posterior delamination and subscapularis tendon tear. The study was conducted from March 2018 to June 2021 with 553 patients who underwent rotator cuff repairs at two institutions. The age and gender, size of rotator cuff tear, duration of symptoms, range of motion of shoulder joint, visual analog scale score, Korean Shoulder Scale score, gap and width of rotator cuff tear, and fatty degeneration of the supraspinatus and infraspinatus muscles were compared to confirm the differences between a delaminated and nondelaminated rotator cuff tear. Moreover, the proportions of the subscapular tendon rupture and subscapularis tendon rupture according to the size of the rotator cuff tear were analyzed in both the delaminated and nondelaminated rotator cuff tear groups. Compared to the nondelaminated rotator cuff tear group, the age of the delaminated rotator cuff tear group was significantly higher, and as the size of the rotator cuff tear increased, the proportion of delaminated tear increased (P<.001). Furthermore, the duration of symptoms was longer, visual analog scale score was higher, Korean Shoulder Scale score was lower, gap and width of rotator cuff as well as fatty degeneration of the supraspinatus and infraspinatus were more severe in the group with posterior delamination than that without. In the nondelaminated rotator cuff tear group, 212 subjects (84.46%) had no subscapularis tear, and 39 subjects (15.54%) had subscapularis tear. In the delaminated rotator cuff tear group, 103 subjects (34.11%) had no subscapular tendon tear while 199 subjects (65.89%) had a subscapular tendon tear (P<.001). Furthermore, as the size of the rotator cuff tear increased, the rate of subscapular tendon tear increased in both the delaminated and nondelaminated rotator cuff tear groups. The results suggest that there is a high probability of concomitant rupture of the subscapularis tendon in the patient group with posterior delamination tear. Therefore, it should be noted that if a posterior delamination is confirmed during surgery, it is necessary to carefully check for rupture of the scapular tendon.

Low-intensity swimming with blood flow restriction over 5 weeks increases VO2peak: A randomized controlled trial using Bayesian informative prior distribution

ABSTRACT Peak oxygen uptake (VO2peak) and speed at first (LT1, minimal lactate equivalent) and second lactate threshold (LT2 = LT1 +1.5 mmol·L−1) are crucial swimming performance surrogates. The present randomized controlled study investigated the effects of blood flow restriction (BFR) during low-intensity swimming (LiT) on VO2peak, LT1, and LT2. Eighteen male swimmers (22.7 ±3.0 yrs; 69.9 ±8.5 kg; 1.8 ±0.1 m) were either assigned to the BFR or control (noBFR) group. While BFR was applied during LiT, noBFR completed the identical LIT without BFR application. BFR of the upper limb was applied via customized pneumatic cuffs (75% of occlusion pressure: 135 ±10 mmHg; 8 cm cuff width). BFR training took place three times a week over 5 weeks (accumulated weekly net BFR training: 60 min·week−1; occlusion per session: 2-times 10 min·session−1) and was used exclusively at low intensities. VO2peak, LT1, and LT2 diagnostics were employed. Bayesian credible intervals revealed notable VO2peak improvements by +0.29 L·min−1 kg−1 (95% credible interval: −0.26 to +0.85 L·min−1 kg−1) when comparing BFR vs. noBFR. Speed at LT1 −0.01 m·s−1 (−0.04 to +0.02 m·s−1) and LT2 −0.01 m·s−1 (−0.03 to +0.02 m·s−1) did not change meaningfully when BFR was employed. Fifteen sessions of LIT swimming (macrocycle of 5 h over 5 weeks) with a weekly volume of 60 min with BFR application adds additional impact on VO2peak improvement compared to noBFR LIT swimming. Occasional BFR applications should be considered as a promising means to improve relevant performance surrogates in trained swimmers. Highlights Low-intensity swimming with blood flow restricted (BFR) induced superior peak oxygen consumption adaptations compared to non-restricted swimming training over a 5-week lasting training period BFR and non-BFR swimming training-induced similar adaptations regarding swimming speed at first and second lactate threshold In conclusion, BFR served as a feasible, promising and beneficial complementary training stimuli to traditional swimming training regarding oxygen consumption adaptations.

A Novel Triple-Bladder Cuff Method for Blood Pressure Estimation Based on Pulse Wave Dynamics in Brachial Artery: Theoretical and Experimental Analyses.

The objective of this study was to develop a novel triple-bladder cuff method for accurate and automated estimation of systolic (SBP) and diastolic (DBP) blood pressure and validate its reliability in animal experiments. The cuff is composed of three bladders each measured one-third the width of a conventional BP cuff, which are designed to measure oscillatory pulsation at the proximal, middle, and distal segments of the upper arm. This structure allows evaluation of the pulse wave propagation in the brachial artery under the cuff. SBP is estimated (SBPe) by detecting resumption of systolic arterial flow based on statistical similarity in oscillatory pulse traces between the proximal and distal segments. DBP is estimated (DBPe) based on the relation between pulse wave velocity and transmural pressure at diastole in the brachial artery. In 7 anesthetized goats, we compared SBPe and DBPe to reference SBP and DBP, respectively, measured by an intra-arterial catheter. BP was perturbed by infusing nitroprusside or noradrenaline. SBP correlated strongly with SBPe in each animal [mean coefficient of determination (R2) = 0.98 ± 0.01]. Mean ± standard deviation of errors between SBP and SBPe was 0.0 ± 4.9 mmHg. DBP correlated strongly with DBPe in each animal (R2 = 0.96 ± 0.03). Mean ± standard deviation of errors between DBP and DBPe was 0.0 ± 6.3 mmHg. This method estimates SBP and DBP with acceptable accuracy. Accurate and automated BP estimation by this method may potentially optimize antihypertensive treatment in patients with hypertension.

A Prediction Equation For Blood Flow Restriction Exercise That Accounts For Cuff Width

Exercise with blood flow restriction (BFR) is an effective strategy to increase muscle size, strength, and function in a variety of populations. However, the determination of arterial occlusion pressure (AOP) needed for BFR exercise prescription requires specialized equipment that limits its accessibility. Previously, researchers have developed prediction equations to estimate AOP using limb circumference and blood pressure. These equations are specific to certain cuff widths and no single equation is available that accounts for varying cuff width. Additionally, it is unclear whether the influence of limb circumference and blood pressure on AOP is consistent across cuffs of varying width. PURPOSE: Our primary purpose was to develop a single prediction equation that estimates AOP in the lower body for a variety of different cuff widths. A secondary purpose was to explore the influence of thigh circumference and systolic blood pressure (SBP) on AOP when using cuffs of varying width. METHODS: Thirty-seven normotensive adults (age: 25 ± 5 yrs, BMI: 25 ± 4 kg/m2) underwent measurements of thigh circumference (TC) and SBP. Next, lower body AOP was assessed (via Doppler ultrasound) in the seated position with an 11, 13, and 18 cm wide cuff. Multiple linear regression analysis including TC, SBP, and cuff width was performed to generate a prediction equation for AOP. A linear mixed effects model was fit, which included AOP as the outcome variable, fixed effects of TC, SBP, cuff width, TC x cuff width, and SBP x cuff width, and a random intercept for participants. RESULTS: For the 11, 13, and 18 cm cuff, AOP was 182 ± 22 mmHg, 168 ± 16 mmHg, and 155 ± 14 mmHg. A model including TC (β = 0.475, part = 2.091), SBP (β = 0.233, part = 0.540), and cuff width explained 63% of the variance in AOP. There were significant main effects of TC, SBP, and cuff width on AOP, and a significant interaction of TC x cuff width (all P < 0.05). CONCLUSION: Our prediction equation including TC and SBP offers a way to estimate AOP in the lower body for a variety of commonly used cuff widths. This equation may help researchers and practitioners implement BFR without the need for specialized equipment. Preliminary results also suggest that the influence of TC on AOP varies with cuff width and thus may need to be taken into account when estimating lower body AOP.

Comparing The Resting Cardiovascular Response To Commonly Used Blood Flow Restriction Devices

Alone, blood flow restriction is used to decrease muscle atrophy or recovery time. However, it is unknown whetherdevices used in clinical or research settings elicit a similar stimulus when using similar protocols. PURPOSE: To compare cardiovascular responses between a commonly used research device (RES) and clinical device (CLIN). METHODS: Over one visit, 24 individuals’ cardiovascular response to blood flow restriction using CLIN and RES devices were measured on the right arm in a randomized and counterbalanced order. After 5 min of supine rest, arterial occlusion pressure (AOP) was measured, then during a second 5 min rest, a near-infrared spectroscopy device was placed at the muscle belly of the forearm to measure tissue deoxygenation (HHb, μm) and tissue saturation index (TSI, %). A pulse oximeter on the index finger measured heart rate (bpm) and % oxygen saturation. 0-10 scale ratings of perceived discomfort (RPE-D, AU) were also assessed. Blood flow (ml/min) was measured using pulsed wave Doppler ultrasonography at the brachial artery proximal to the antecubital space. All variables were assessed twice at 0% AOP and once at 50% AOP. Measures were spaced 1 min apart. Change scores (50% AOP - 0% AOP) and AOP presented as mean ± SD, were compared using Bayesian paired samples t-tests (JASP). RESULTS: AOP differed between RES (157.13 ± 19.54) and CLIN (143.17 ± 16.92; BF10 = 156.75). However, weak to moderate evidence suggested that changes in blood flow volume (RES: -33.13 ± 30.64; CLIN: -28.71 ± 28.75; BF10 = .41), TSI (RES: -4.68 ± 5.17; CLIN: -4.92 ± 5.50; BF10 = 0.23), heart rate (RES: 0 ± 3; CLIN: 0 ± 7; BF10 = 0.22), and oxygen saturation (RES: -1 ± 1; CLIN: -1 ± 1; BF10 = 0.25) did not differ between the devices. Moderate evidence suggested HHb for channel 1 (RES: 16.48 ± 5.50; CLIN: 16.41 ± 6.69; BF10 = 0.22), channel 2 (RES: 16.12 ± 4.84; CLIN: 15.89 ± 6.21; BF10 = 0.22), and channel 3 did not differ (RES: 15.44 ± 4.53; CLIN: 15.13 ± 5.78; BF10 = 0.23) between devices. Moderate evidence also suggested RPE-D did not differ (RES: 1.06 ± 1.29; CLIN: 1.10 ± 1.30; BF10 = 0.22). CONCLUSION: AOP measurements differed between devices, possibly due to cuff width, material, and/or assessment method. However, this did not lead to a difference in cardiovascular responses when applying a relative pressure of 50% AOP for each device.

An Overview of Blood Flow Restriction Physiology and Clinical Considerations.

The utilization of blood flow restriction has garnished considerable attention due to its widespread application and benefits that include strength enhancement, muscle hypertrophy, and increased level of function for specific populations. Blood flow restriction induces a hypoxic environment within a muscle group, initiating a metabolic cascade that stimulates muscle protein synthesis, altered gene regulation of muscle satellite cells, and increased muscle fiber recruitment, ultimately resulting in improved strength and endurance. When using blood flow restriction, consideration of the individual patient, occlusion pressure, cuff width, and cuff size are paramount. Blood flow restriction has been proven to be a consistently safe and effective tool for augmenting rehabilitative regimens for the upper and lower extremity.

Agreement of caudal aortic arterial blood pressure with oscillometry using two cuff widths placed on the thoracic or pelvic limbs of sevoflurane-anesthetized rabbits

ObjectiveTo evaluate agreement with central systemic arterial pressure of an oscillometer and two cuff widths placed on the thoracic or pelvic limbs. Study designProspective experimental study. AnimalsA group of nine New Zealand White rabbits weighing 3.5 ± 0.3 kg. MethodsRabbits were sedated with dexmedetomidine and midazolam, then anesthetized with ketamine and sevoflurane. The femoral artery was surgically exposed and a 20 gauge, 5 cm catheter inserted to measure systolic (SAP), mean (MAP) and diastolic (DAP) blood pressure at the iliac artery and caudal aorta junction. Adjustments of vaporizer dial and dobutamine infusion provided a range of invasive blood pressure (IBP). Two measurements of IBP were recorded during the oscillometer cycling phase, and the mean value was used in analyses. Oscillometer cuffs of bladder width 2.0 cm (S1) and 2.5 cm (S2) were placed proximal to the carpus and tarsus. Cuff width to circumference ratio was calculated. Oscillometer SAP, MAP and DAP were paired with corresponding IBP values. Agreement was assessed using linear mixed models (p < 0.05). ResultsCuff ratios for both limbs were 41% (S1 cuff) and 50% (S2 cuff) and 122–139 paired observations were obtained. There was significant limb × cuff interaction with SAP and MAP. The oscillometer overestimated SAP and MAP on the pelvic limb and underestimated SAP and MAP on the thoracic limb. For SAP, the oscillometer overestimated by constant bias (–19 ± 2 mmHg) and proportional bias (0.28 ± 0.02 mmHg per 1 mmHg increase). For MAP, the oscillometer underestimated by constant bias (4 ± 2 mmHg) and was worse with S2 on the thoracic limb. Overestimation was similar between cuffs on the pelvic limb. For DAP, the oscillometer underestimated by constant bias (15 ± 2 mmHg). Conclusions and clinical relevanceCuff S1 on the thoracic limb provided best estimation of MAP.

The impact of cuff width on perceptual responses during and following blood flow restricted walking exercise.

An appropriate comparison of different cuff widths during blood flow restricted exercise requires that the cuffs are inflated to the same relative pressures. Narrow cuffs tend to be preferred and may reduce discomfort when applied during resistance exercise, but whether this is also true during walking exercise remains unknown. Individuals completed two identical walking trials, once with 12-cm wide cuffs and once with 17-cm wide cuffs. Five 2-min walking bouts were completed at a speed of 50m/min, with a 1-min rest period between sets. The restriction cuffs were inflated to 40% of the individuals' arterial occlusion pressure taken with each respective cuff. Individuals were asked to rate their discomfort, perceived exertion (RPE), and cuff preference. Twenty-seven individuals completed the study. The 12-cm cuff required a higher occlusion pressure which resulted in a higher absolute pressure applied (58 vs. 52mmHg; BF10 =19331.897). Whilst there was no difference in RPE values between cuffs (BF10 =0.474), individuals reported greater discomfort when using the wider cuffs (2.3 vs. 1.7; BF10 =252.786). The majority of individuals (63%) preferred to use the narrower cuff, whereas fewer preferred the wider cuff (26%) and even fewer did not have a preference (11%). Blood flow restricted walking exercise performed with narrower restriction cuffs appeared to reduce participant discomfort whilst also being preferred over that of wider cuffs. Future studies may wish to test the influence of different restrictive cuff widths on alterations in gait patterns during blood flow restricted walking exercise.

What Are Practical Surgical Anatomic Landmarks and Distances from Relevant Neurologic Landmarks in Cadavers for the Posterior Approach in Shoulder Arthroplasty?

Traditional total shoulder arthroplasty is performed through the deltopectoral approach and includes subscapularis release and repair. Subscapularis nonhealing or dysfunction may leave patients with persistent pain, impairment, and instability. Alternative approaches that spare the subscapularis include rotator interval and posterior shoulder approaches; however, to our knowledge, a cadaveric study describing pertinent surgical anatomy for a posterior shoulder approach regarding shoulder arthroplasty has not been performed. (1) What are the distances from important neurologic structures of the shoulder for arthroplasty through a posterior approach? (2) What surgical landmarks can help identify the internervous interval between the infraspinatus and teres minor? Twelve hemitorso cadaver specimens with intact rotator cuffs were dissected to study posterior shoulder anatomy regarding posterior shoulder arthroplasty. The median (range) age of the specimens was 79 years (55 to 92). Six of the 12 specimens were right-hand dominant, and 10 specimens were male. Cadaver height was a median 171 cm (155 to 191) and weight was a median of 68 kg (59 to 125). A posterior deltoid split and internervous approach between the infraspinatus and teres minor were used. A posterior T capsulotomy was performed. The distances to important neurologic structures were measured with an electronic caliper and provided in median (range) distances in millimeters. Although not as meaningful as distance ratios accounting for a specimen's body size, neurologic distances in millimeters are surgically practical and provide intraoperative usefulness. Surgical landmarks that can help identify the infraspinatus and teres minor plane were noted. Practical visual and tactile cues between the infraspinatus and teres minor were identified. Posterior rotator cuff tendon morphologies and widths were recorded. The closest important neurologic structure was the axillary nerve, measuring a median (range) 17 mm (9 to 19) from the inferior glenoid rim while the infraspinatus branch of the suprascapular nerve measured 21 mm (15 to 36) from the posterior glenoid rim. The axillary nerve measured 84 mm (70 to 97) from the posterior tip of the acromion in the deltoid split. Three surgical landmarks were helpful for identifying the plane between the infraspinatus and teres minor in all 12 specimens: (1) identifying the triangular teres minor tendon insertion, (2) medial palpation identifying the low point between the prominent muscle bellies of the infraspinatus and teres minor, and (3) identifying the distinct and prominent teres minor tubercle, which is well localized and palpable. A major benefit of the posterior approach for shoulder arthroplasty is subscapularis preservation. Multiple practical surgical cues are consistently present and can help identify the infraspinatus and teres minor interval. We did not find the presence of fat stripes to be helpful. The suprascapular nerve is in proximity to posterior surgical dissection and differs from the deltopectoral approach. This is an important distinction from an anterior approach and requires care with dissection. Future studies are necessary to assess iatrogenic risk to the posterior rotator cuff and external rotation strength. This may entail intraoperative nerve conduction studies of the posterior rotator cuff and clinical studies assessing external rotation strength. Studying posterior shoulder anatomy is an initial first step to assessing the feasibility of the posterior approach for anatomic shoulder arthroplasty. Additional studies assessing the degree of glenohumeral exposure and possible iatrogenic posterior rotator cuff injury are necessary. Because of the proximity of neurologic structures, it is recommended that surgeons not perform this technique until sufficient evidence indicates that it is equivalent or superior to standard anterior approach total shoulder arthroplasty. After such evidence is available, proper training will be necessary to ensure safe use of the posterior shoulder approach.

Measurements of rotator cuff tendons, acromioclavicular joint space, and subacromion-subdeltoid bursa in the adults sudanese population using ultrasonography

ABSTRACT Globally, musculoskeletal disorders have risen. Injuries at work are common, and workers’ compensation and medical costs can be costly. The study’s goal was to employ high-frequency ultrasound (US) to determine rotator cuff tendon thickness and width, acromioclavicular joint (ACJ) space, and subacromion-subdeltoid (SA-SD) bursa thickness in Sudanese. These will also be standard reference levels for early diagnosis of musculoskeletal diseases. The study comprised 286 adults aged 18 to 82 years with 35% males and 65% females.The Statistical Package for the Social Sciences (SPSS) version 16.0 for Microsoft Windows was used to analyze the data. The study found that the mean thickness and width of the long head of the biceps (LHB), subscapularis (Ssc), supraspinatus (SS), and infraspinatus (IS) tendons were 2.71±0.50 mm; 6.28±0.97 mm, 4.55±0.84 mm; 26.59±2.83 mm, 5.34±0.98 mm; 27.32±2.66 mm, and 2.51±0.65 mm; 26.22±3.12 mm, respectively. The average ACJ space measurement was 5.01±0.61 mm and the SA-SD bursa thickness was 1.40±0.33. This study determined the mean thickness and width of the LHB, Ssc, SS, and IS tendons, the ACJ space, and the SA-SD bursa in healthy adult Sudanese. These findings should be included in the musculoskeletal US (MSK US) interpretation checklist for shoulder joint disorders.

Systolic Blood Pressure in Anesthetized Dogs - Agreement between Measurements by Two Noninvasive Monitors

Background: The oscillometric monitor is a noninvasive method used for measuring blood pressure in dogs and cats. Despite widely used, there is a large variability in the accuracy of oscillometric monitors, which may also be influenced by the location of the blood pressure cuff. The Doppler ultrasound is another non-invasive method that was shown to measure blood pressure with good accuracy and precision in small animals. The present study aimed to determine the agreement between systolic arterial pressure (SAP) measured by the Prolife P12 oscillometric monitor with two cuff locations and the Doppler ultrasound in anesthetized dogs.Materials, Methods &amp; Results: Dogs scheduled for routine anesthetic procedures were included in the study, which was carried out in two phases. In Phase 1, SAP values measured by the Doppler were compared with those measured by the Prolife P12 monitor with the cuff placed at the thoracic limb for both methods. In Phase 2, SAP values measured by the Doppler were compared with those measured by the Prolife P12 monitor, with the cuff placed at the thoracic limb for the Doppler and at the base of the tail for the P12. The cuff width corresponded to approximately 40% of limb or tail circumference. On all occasions, three consecutive measurements of SAP were recorded, followed by a single measurement of SAP by the P12, and then other three measurements were performed with the Doppler. The arithmetic mean of the six SAP measurements with the Doppler was compared with the SAP value measured by the P12 monitor (paired measurements). Agreement between SAP values measured by the Doppler and the P12 monitor was analyzed by the Bland Altman method for calculation of the bias (Doppler – P12) and standard deviation (SD) of the bias. The percentages of differences between the methods with an error ≤ 10 mmHg and ≤ 20 mmHg and Pearson’s correlation coefficients were also calculated. Results were compared with the criteria from the American College of Veterinary Internal Medicine (ACVIM) for validation of noninvasive blood pressure methods. A total of 33 dogs were included in Phase 1 and 15 were included in Phase 2. During Phases 1 and 2, 179 and 87 paired measurements were recorded, respectively. Most of the measurements were recorded during normotension (SAP = 90-130 mmHg): 113/179 in Phase 1 and 52/87 in Phase 2. The bias (± SD) for Phases 1 and 2 were -2.7 ± 14.1 mmHg and 7.2 ± 25.8 mmHg. The percentages of differences ≤ 10 mmHg and ≤ 20 mmHg were: Phase 1, 61% and 83%; Phase 2, 41% and 70%. Correlation coefficients were 0.81 and 0.67 for Phases 1 and 2, respectively. According to the ACVIM criteria, maximum values accepted for bias are 10 ± 15 mmHg, the percentages of differences ≤ 10 mmHg and ≤ 20 mmHg should be ³ 50% and ³ 80%, respectively, and the correlation coefficient should be ³ 0.9. Discussion: When the blood pressure cuff was placed at the thoracic limb, SAP values measured by the P12 monitor met most of the ACVIM criteria, demonstrating good agreement with SAP values measured by the Doppler. The only requirement not met was the correlation coefficient which was 0.81 whereas the recommended is ³ 0.9. Conversely, when the cuff was placed at the base of the tail, SAP values measured by the P12 monitor did not meet most of the ACVIM criteria indicating that, in anesthetized dogs, SAP measurements with the P12 monitor should be performed with the cuff placed at the thoracic limb. One limitation of this study was that most measurements fell in the normotensive range and the results should not be extrapolated for hypotensive and hypertensive conditions. In conclusion, the Prolife P12 oscillometric monitor demonstrated good agreement with SAP values measured by the Doppler and provides acceptable values in normotensive anesthetized dogs.Keywords: arterial blood pressure, nonivasive blood pressure, anesthetic monitoring.Título: Pressão arterial sistólica em cães anestesiados - concordância entre mensurações por dois métodos não invasivosDescritores: pressão arterial, pressão arterial não invasiva, monitoração anestésica.

Influencing factors and rules of shielding effectiveness of electromagnetic shielding clothing sleeve

PurposeThe change rules of the shielding effectiveness (SE) of the sleeve has not been clarified, which leads to the lack of the basis for the design, manufacture and evaluation of the electromagnetic shielding (EMS) clothing.Design/methodology/approachAccording to a simplified analysis model, a series of sleeve samples with different fabrics and styles are designed and manufactured. The SE of the sleeve is tested with the proposed special test method in a semi-anechoic chamber to analyze the influence of different factors on the SE of the sleeve.FindingsThe SE is greatly reduced about 60–90% after the fabric is manufactured into the sleeve. The larger the sleeve length is, the higher the peak value of the SE is. When the sleeve length is low, the SE value is easy to appear negative. As the cuff circumference increases, the SE of the sleeve will change with the frequency band. The influence of the cuff style on the SE of the sleeve mainly depends on the cuff width and style. The larger the cuff width is, the lower the overall SE of the sleeve is. The more wrinkles there are at the cuff, the better the SE of the sleeve is.Originality/valueOur results provide a reference for the design, production and evaluation of the sleeve and the whole EMS clothing.