scholarly journals Quantification of stroke volume in a simulated healthy volunteer model of traumatic haemorrhage; a comparison of two non-invasive monitoring devices using error grid analysis alongside traditional measures of agreement

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0261546
Author(s):  
Sam D. Hutchings ◽  
Jim Watchorn ◽  
Rory McDonald ◽  
Su Jeffreys ◽  
Mark Bates ◽  
...  
Keyword(s):  
Stroke Volume ◽  
Lower Limb ◽  
Measurement Errors ◽  
Dynamic Change ◽  
Traumatic Injury ◽  
Haemodynamic Monitoring ◽  
Percentage Error ◽  
Circulating Blood Volume ◽  
Measures Of Agreement ◽  
Error Grid

Introduction Haemorrhage is a leading cause of death following traumatic injury and the early detection of hypovolaemia is critical to effective management. However, accurate assessment of circulating blood volume is challenging when using traditional vital signs such as blood pressure. We conducted a study to compare the stroke volume (SV) recorded using two devices, trans-thoracic electrical bioimpedance (TEB) and supra-sternal Doppler (SSD), against a reference standard using trans- thoracic echocardiography (TTE). Methods A lower body negative pressure (LBNP) model was used to simulate hypovolaemia and in half of the study sessions lower limb tourniquets were applied as these are common in military practice and can potentially affect some haemodynamic monitoring systems. In order to provide a clinically relevant comparison we constructed an error grid alongside more traditional measures of agreement. Results 21 healthy volunteers aged 18–40 were enrolled and underwent 2 sessions of LBNP, with and without lower limb tourniquets. With respect to absolute SV values Bland Altman analysis showed significant bias in both non-tourniquet and tourniquet strands for TEB (-42.5 / -49.6 ml), rendering further analysis impossible. For SSD bias was minimal but percentage error was unacceptably high (35% / 48%). Degree of agreement for dynamic change in SV, assessed using 4 quadrant plots showed a seemingly acceptable concordance rate for both TEB (86% / 93%) and SSD (90% / 91%). However, when results were plotted on an error grid, constructed based on expert clinical opinion, a significant minority of measurement errors were identified that had potential to lead to moderate or severe patient harm. Conclusion Thoracic bioimpedance and suprasternal Doppler both demonstrated measurement errors that had the potential to lead to clinical harm and caution should be applied in interpreting the results in the detection of early hypovolaemia following traumatic injury.

scholarly journals An exploratory natural history of ataxia of Charlevoix-Saguenay

Neurology ◽  
2018 ◽  
Vol 91 (14) ◽  
pp. e1307-e1311 ◽  
Author(s):  
Cynthia Gagnon ◽  
Isabelle Lessard ◽  
Caroline Lavoie ◽  
Isabelle Côté ◽  
Raphaël St-Gelais ◽  
...  
Keyword(s):  
Lower Limb ◽  
Measurement Errors ◽  
Motor Coordination ◽  
Longitudinal Design ◽  
Berg Balance Scale ◽  
Significant Decline ◽  
Walk Test ◽  
Limb Coordination ◽  
History Of ◽  
6 Minute Walk Test

ObjectiveTo document the decline of upper and lower limb functions, mobility, and independence in daily living activities in adults with autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) over a 2-year period.MethodsAn exploratory longitudinal design was used. Nineteen participants were assessed on 2 occasions 2 years apart. Assessments included the Standardized Finger Nose Test, Nine-Hole Peg Test, Lower Extremity Motor Coordination Test, Berg Balance Scale, 10-m walk test (10mWT), 6-minute walk test (6MWT), Scale for the Assessment and Rating of Ataxia (SARA), and Barthel Index.ResultsA significant decline was observed between baseline and follow-up for lower limb coordination, balance, walking abilities (10mWT and 6MWT), and overall disease severity (SARA). All differences were beyond measurement error documented in ARSACS. Results showed no significant decline for upper limb coordination and fine dexterity performance.ConclusionAlthough ARSACS is a slow, progressive disease, results showed that mobility, balance, and lower limb performance significantly decreased over the 2-year period and that selected outcome measures were able to capture this decline beyond measurement errors.

The mental health problems and needs of older people following lower-limb amputation

2006 ◽  
Vol 16 (2) ◽  
pp. 155-163 ◽  
Author(s):  
Wendy Briggs
Keyword(s):  
Mental Health ◽  
At Risk ◽  
Older People ◽  
Lower Limb ◽  
Mental Health Problems ◽  
Traumatic Injury ◽  
Lower Limb Amputation ◽  
Limb Amputation ◽  
Anecdotal Evidence ◽  
The Past

In the past, most amputees have been veterans of war or other younger people who have sustained traumatic injury. There are now an increasing number of older people undergoing lower-limb amputation, most commonly because of vascular problems. Anecdotal evidence suggests that there is a lack of support for patients facing limb amputation, and a lack of recognition from staff that these patients may be at risk of ongoing psychological problems following the procedure.

Acute bone changes after lower limb amputation resulting from traumatic injury

2017 ◽  
Vol 28 (7) ◽  
pp. 2177-2186 ◽  
Author(s):  
D. A. Bemben ◽  
V. D. Sherk ◽  
W. J. J. Ertl ◽  
M. G. Bemben
Keyword(s):  
Lower Limb ◽  
Traumatic Injury ◽  
Lower Limb Amputation ◽  
Limb Amputation ◽  
Bone Changes

scholarly journals Effects of Lower Limb and Pelvic Pin Positions on Leg Length and Offset Measurement Errors in Experimental Total Hip Arthroplasty

2021 ◽  
Author(s):  
Haruo Kawamura ◽  
Yasuhiko Watanabe ◽  
Tomofumi Nishino ◽  
Hajime Mishima
Keyword(s):  
Measurement Error ◽  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Lower Limb ◽  
Measurement Errors ◽  
Iliac Crest ◽  
External Rotation ◽  
Limb Position ◽  
Permissible Range ◽  
Flexion Extension

Abstract BackgroundLeg length (LL) and offset (OS) are important factors in total hip arthroplasty (THA). Because most LL and OS callipers used in THA depend on fixed points on the pelvis and the femur, limb position could affect measurement error. This study was conducted on a THA simulator to clarify the effects of lower limb position and iliac pin position on LL and OS errors and to determine the permissible range of limb position for accurate LL and OS measurement. MethodsAn LL and OS measurement instrument was used. Two pin positions were tested: the iliac tubercle and the top of the iliac crest intersecting with the extension of the femoral axis. First, the limb was moved in one direction (flexion-extension, abduction-adduction, or internal-external rotation), and LL and OS were measured for each pin position. Next, the limb was moved in combinations of the three directions. Then, the permissible range of combined limb position, which resulted in LL and OS measurement error within ±2 mm, was determined for each pin position. ResultsOnly 4 degrees of abduction/adduction caused 5-7 mm error in LL and 2-4 mm error in OS, irrespective of pin position. The effects of flexion–extension and internal–external rotation on LL error were smaller for the top of the iliac crest than for the iliac tubercle, though OS error was similar for both pin positions. For LL, the permissible range of the combined limb position was wider for the top of the iliac crest than for the iliac tubercle. ConclusionTo minimize LL and OS measurement errors in THA, adduction–abduction must be maintained. The iliac pin position in the top of the iliac crest is preferred because it provides less LL measurement error and a wider permissible range of combined limb position for accurate LL measurement.

Digital infrared thermographic imaging for remote assessment of traumatic injury

2011 ◽  
Vol 111 (6) ◽  
pp. 1813-1818 ◽  
Author(s):  
William H. Cooke ◽  
Gilbert Moralez ◽  
Chelsea R. Barrera ◽  
Paul Cox
Keyword(s):  
Stroke Volume ◽  
Respiratory Rate ◽  
Skin Temperature ◽  
Lower Body Negative Pressure ◽  
Traumatic Injury ◽  
Sign Detection ◽  
Thermographic Imaging ◽  
Thermographic Camera ◽  
Remote Assessment ◽  
Injured Patients

The purpose of this study was to test the hypotheses that digital infrared thermographic imaging (DITI) during simulated uncontrolled hemorrhage will reveal 1) respiratory rate and 2) changes of skin temperature that track reductions of stroke volume. In 45 healthy volunteers (25 men and 20 women), we recorded the ECG, finger photoplethysmographic arterial pressure, respiratory rate (pneumobelt and DITI of the nose), cardiac output (inert rebreathing), and skin temperature of the forehead during lower body negative pressure (LBNP) at three continuous decompression rates; slow (−3 mmHg/min), medium (−6 mmHg/min), and fast (−12 mmHg/min) to an ending pressure of −60 mmHg. Respiratory rates calculated from the pneumobelt (14.7 ± 0.9 breaths/min) and DITI (14.9 ± 1.2 breaths/min) were not different ( P = 0.21). LBNP induced an average stroke volume reduction of 1.3 ml/mmHg regardless of decompression speed. Maximal reductions of stroke volume and forehead temperature were −100 ± 12 ml and −0.32 ± 0.12°C (slow), −86 ± 12 ml and −0.74 ± 0.27°C (medium), and −78 ± 5 ml and −0.17 ± 0.02°C (fast). Changes of forehead temperature as a function of changes of stroke volume were best described by a quadratic fit to the data (slow R2 = 0.95; medium R2 = 0.89; and fast R2 = 0.99).Our results suggest that a thermographic camera may prove useful for the remote assessment of traumatically injured patients. Life sign detection may be determined by verifying respiratory rate. Determining the magnitude and rate of hemorrhage may also be possible based on future algorithms derived from associations between skin temperature and stroke volume.

scholarly journals Estimation of Displacement for Internet of Things Applications with Kalman Filter

Electronics ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 985 ◽  
Author(s):  
Renato Ferrero ◽  
Filippo Gandino ◽  
Masoud Hemmatpour
Keyword(s):  
Kalman Filter ◽  
Internet Of Things ◽  
Measurement Errors ◽  
Physical World ◽  
Percentage Error ◽  
Double Integration ◽  
Computational Overhead ◽  
Aggregate Information ◽  
Correction Technique ◽  
Types Of Information

In the vision of the Internet of Things, an object embedded in the physical world is recognizable and becomes smart by communicating data about itself and by accessing aggregate information from other devices. One of the most useful types of information for interactions among objects regards their movement. Mobile devices can infer their position by exploiting an embedded accelerometer. However, the double integration of the acceleration may not guarantee a reliable estimation of the displacement of the device (i.e., the difference in the new location). In fact, noise and measurement errors dramatically affect the assessment. This paper investigates the benefits and drawbacks of the use of the Kalman filter as a correction technique to achieve more precise estimation of displacement. The approach is evaluated with two accelerometers embedded in commercial devices: A smartphone and a sensor platform. The results show that the technique based on the Kalman filter dramatically reduces the percentage error, in comparison to the assessment made by double integration of the acceleration data; in particular, the precision is improved by up to 72%. At the same time, the computational overhead due to the Kalman filter can be assumed to be negligible in almost all application scenarios.

scholarly journals A meta-analysis on anticoagulation after vascular trauma

2020 ◽  
Vol 46 (6) ◽  
pp. 1291-1299 ◽  
Author(s):  
Shujhat Khan ◽  
Hussein Elghazaly ◽  
Areeb Mian ◽  
Mansoor Khan
Keyword(s):  
Lower Limb ◽  
Meta Analysis ◽  
Traumatic Injury ◽  
Vascular Trauma ◽  
Vascular Repair ◽  
Trauma Outcomes ◽  
Ovid Medline ◽  
Mesh Terms ◽  
Trauma Outcome ◽  
Reduced Risk

Abstract Purpose There is much debate regarding the use of anticoagulation following vascular trauma. The aim of this meta-analysis was to compare the outcome of trauma following administration of anticoagulation medication. Methods The literature search was carried out using Ovid MEDLINE and PubMed databases to search for keywords and MeSH terms including “Anticoagulation”, “Vascular Surgery”, “Vascular Trauma”, “Vascular Repair”, “Repair” and “Wounds and Injuries”. Results Use of anticoagulation was associated with a better prognosis for overall vascular trauma outcomes (weighted OR 0.46; 95% CI 0.34–0.64; P < 0.00001), as well as reduced risk of amputation for both lower and upper limb vascular trauma (weighted OR 0.42; 95% CI 0.22–0.78; P = 0.007), and reduced occurrence of reoperation events and amputations in isolated lower limb vascular trauma (weighted OR 0.27; 95% CI 0.14–0.52; P < 0.0001). Conclusion There was a statistically significant correlation between the use of anticoagulation and vascular trauma outcome. A major limitation with many of the studies includes a lack of prospective analysis and therefore we recommend prospective studies to properly elucidate prognostic outcomes following use of these anticoagulants. Further studies need to be conducted to assess the effects of timing of anticoagulant delivery, dosages and severity of traumatic injury. Thus, this would prove to be very useful in the formation of guidelines.

scholarly journals Effects of lower limb and pelvic pin positions on leg length and offset measurement errors in experimental total hip arthroplasty

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Haruo Kawamura ◽  
Yasuhiko Watanabe ◽  
Tomofumi Nishino ◽  
Hajime Mishima
Keyword(s):  
Measurement Error ◽  
Total Hip Arthroplasty ◽  
Lower Limb ◽  
Measurement Errors ◽  
Iliac Crest ◽  
External Rotation ◽  
Leg Length ◽  
Limb Position ◽  
Permissible Range ◽  
Flexion Extension

Abstract Background Leg length (LL) and offset (OS) are important factors in total hip arthroplasty (THA). Because most LL and OS callipers used in THA depend on fixed points on the pelvis and the femur, limb position could affect measurement error. This study was conducted on a THA simulator to clarify the effects of lower limb position and iliac pin position on LL and OS errors and to determine the permissible range of limb position for accurate LL and OS measurement. Methods An LL and OS measurement instrument was used. Two pin positions were tested: the iliac tubercle and the top of the iliac crest intersecting with the extension of the femoral axis. First, the limb was moved in one direction (flexion-extension, abduction-adduction, or internal-external rotation), and LL and OS were measured for each pin position. Next, the limb was moved in combinations of the three directions. Then, the permissible range of combined limb position, which resulted in LL and OS measurement error within ±2 mm, was determined for each pin position. Results Only 4° of abduction/adduction caused 5–7 mm error in LL and 2–4 mm error in OS, irrespective of pin position. The effects of flexion–extension and internal–external rotation on LL error were smaller for the top of the iliac crest than for the iliac tubercle, though OS error was similar for both pin positions. For LL, the permissible range of the combined limb position was wider for the top of the iliac crest than for the iliac tubercle. Conclusion To minimize LL and OS measurement errors in THA, adduction–abduction must be maintained. The iliac pin position in the top of the iliac crest is preferred because it provides less LL measurement error and a wider permissible range of combined limb position for accurate LL measurement.

scholarly journals Effect of limb rotation on radiographic alignment measurement in mal-aligned knees

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Xiaoshu Sun ◽  
Bin Yang ◽  
Shengzhao Xiao ◽  
Yichen Yan ◽  
Zifan Liu ◽  
...  
Keyword(s):  
Lower Limb ◽  
Knee Flexion ◽  
Measurement Errors ◽  
Mechanical Axis ◽  
Weight Bearing ◽  
Correlation Coefficients ◽  
Lower Limbs ◽  
Limb Alignment ◽  
Lower Limb Alignment ◽  
Accuracy Of Measurements

Abstract Purpose Long-leg-radiography (LLR) is commonly used for the measurement of lower limb alignment. However, limb rotations during radiography may interfere with the alignment measurement. This study examines the effect of limb rotation on the accuracy of measurements based on the mechanical and anatomical axes of the femur and tibia, with variations in knee flexion and coronal deformity. Methods Forty-five lower limbs of 30 patients were scanned with CT. Virtual LLRs simulating five rotational positions (neutral, ± 10$$^{\circ }$$ ∘ , and ± 20$$^{\circ }$$ ∘ internal rotation) were generated from the CT images. Changes in the hip–knee–ankle angle (HKA) and the femorotibial angle (FTA) were measured on each image with respect to neutral values. These changes were related to knee flexion and coronal deformity under both weight- and non-weight-bearing conditions. Results The measurement errors of the HKA and FTA derived from limb rotation were up to 4.84 ± 0.66$$^{\circ }$$ ∘ and 7.35 ± 0.88$$^{\circ }$$ ∘ , respectively, and were correlated with knee flexion (p < 0.001) and severe coronal deformity (p < 0.001). Compared with the non-weight-bearing position, the coronal deformity measured in the weight-bearing condition was 2.62$$^{\circ }$$ ∘ greater, the correlation coefficients between the coronal deformity and the deviation ranges of HKA and FTA were also greater. Conclusions Flexion and severe coronal deformity have a significant influence on the measurement error of lower limb alignment. Errors can be amplified in the weight-bearing condition compared with the non-weight-bearing condition. When using HKA and FTA to represent the mechanical axis and the anatomical axis on LLR, limb rotation impacts the anatomic axis more than the mechanical axis in patients with severe deformities. Considering LLR as the gold standard image modality, attention should be paid to the measurement of knee alignment. Especially for the possible errors derived from weight-bearing long-leg radiographs of patients with severe knee deformities.

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