Thoughts for tester[edit | edit source]
- Tourniquet is 1.5 inches (3.81 cm) wide, same as CAT and RMT
- Thinking that 325 - 400 mmHg considered "perfect" 250-325mmHg and 400-475 mmHg considered "good" and outside these ranges considered "not good" for adults with regular blood pressure -- maybe shift these ranges up, staying at 475 mmHg as upper limit. Nerve damage becomes risk at 500 so we should start calling them bad before that is reached, so if they are applied tighter during actual use vs training there is leeway. These likely too high need lower and adjust for width of tourniquet
- Include a start and done button, for timing application, for training.
- Need arm and leg version? maybe with diff pressure targets? Yes
- For arm, 210-310 mmHg target/typical. For thigh, 250-350. This will show people approximately how tight tourniquet should be, if they dont have a way of measuring. 500 mmHg hard upper limit, do not go higher than this unless absolutely needed.
The Safety of the Esmarch Tourniquet[edit | edit source]
Biehl, W. C., Morgan, J. M., Wagner, F. W., & Gabriel, R. A. (1993). The Safety of the Esmarch Tourniquet. Foot & Ankle, 14(5), 278–283. https://doi.org/10.1177/107110079301400508
Abstract[edit | edit source]
"The use of an Esmarch bandage as a tourniquet in surgery has been criticized. Many authors claim that the pressures under the Esmarch are inconsistent and may be extremely high. We have seen few, if any, problems from the use of an Esmarch in surgery of the foot and ankle. The purpose of this study was to evaluate the pressures generated under the Esmarch tourniquet in a situation that mimics its clinical application, and to determine whether pressures of appropriate magnitude and consistency are obtained in order to recommend its continued use in surgery.
Ten volunteers performed numerous applications of the Esmarch. The number of wraps and the width of the Esmarch bandage used were varied. The Esmarch was applied as it would be for a surgical case. Pressures directly beneath the Esmarch were recorded 8 cm proximal to the distal tip of the medial malleolus.
Considering all volunteers and all pressures generated, a 3-in Esmarch applied with three wraps gave a mean pressure (±SD) of 225 ± 46 mm Hg. A 3-in Esmarch applied with four wraps gave a mean pressure of 291 ± 53 mm Hg. A 4-in Esmarch applied with three wraps gave a mean pressure of 233 ± 35 mm Hg, and a 4-in Esmarch with four wraps gave a mean pressure of 284 ± 42 mm Hg. The maximum pressures generated by any individual were as follows: 3-in three wraps, 321 mm Hg; 3-in four wraps, 413 mm Hg; 4-in three wraps, 328 mm Hg; and 4-in four wraps, 380 mm Hg. There was no significant difference in the magnitude or consistency of pressures generated between the experienced and inexperienced wrappers. There did not appear to be a learning curve for the application of the Esmarch bandage.
We conclude that an Esmarch bandage, used as a tourniquet, can generate safe and reliable pressures. Either a 3-in or 4-in Esmarch bandage applied above the ankle with three circumferential overlapping wraps consistently results in pressures that are in a safe range."
Notes[edit | edit source]
- 8cm to 13cm infant blood pressure cuff used as pressure sensor
- pressure greater than 400 mmHg considered unsafe
- 250 mmHg around ankle considered safe
Appropriate Tourniquet Types in the Pediatric Population: A Systematic Review[edit | edit source]
Cureus | Appropriate Tourniquet Types in the Pediatric Population: A Systematic Review. (n.d.). Retrieved June 10, 2022, from https://www.cureus.com/articles/55597-appropriate-tourniquet-types-in-the-pediatric-population-a-systematic-review
Abstract[edit | edit source]
"Trauma is the leading cause of mortality in those aged 1-19, with hemorrhage accounting for up to 40% of all trauma deaths. Manufactured tourniquets are recommended for the control of life-threatening extremity hemorrhage in adults but their use in the pediatric population requires further investigation. We performed a systematic review to evaluate the most appropriate tourniquet design for use in the pediatric population. A literature search of Embase and the Cochran databases of trials and systematic reviews on October 1, 2020 identified 454 unique references, of which 15 were included for full-text screening. Two single-arm observational studies with a high risk of bias evaluated the use of windlass tourniquets in the pediatric population (73 patients, age 2-16 years). The certainty of the evidence was very low. In both studies, conducted on uninjured extremities, the use of a manufactured windlass tourniquet, specifically the Combat Application Tourniquet (C-A-T®) Generation 7, led to the cessation of Doppler detected pulses in 71/71 (100%) of upper extremities and 69/73 (94.5%) of lower extremities. Of the four failures, one participant withdrew due to pain and three tourniquet applications failed to occlude pulses after three turns of the windlass. No controls were used for comparison. In conclusion, two observational studies demonstrated that windlass tourniquets were able to abolish distal pulses in children as young as two years of age and with a minimum limb circumference of 13 cm. These preliminary findings may be helpful for organizations in the creation of guidelines for the management of life-threatening extremity bleeding in children."
Notes[edit | edit source]
- Successful application determined by distal pulse cessation, detected by Doppler ultrasound
- 3 experimental studies of different types of tourniquet types for pediatric use have been done on manikins/PVC pipe/stair rails
- Human Testing
CoTCC Expands Recommended Tourniquet List[edit | edit source]
CoTCC Expands Recommended Tourniquet List. (n.d.). Retrieved June 10, 2022, from http://wms.org/magazine/1245/tourniquet
Introduction[edit | edit source]
"The Committee on Tactical Combat Casualty Care (CoTCCC) recently reviewed many commercially available tourniquets to determine their effectiveness based on a predetermined set of standardized criteria. In early May 2019, the CoTCCC announced the findings of this extensive evaluation and added many new tourniquets to their recommended list. The primary goals of this tourniquet review were: (1) review the previously recommended tourniquets for effectiveness and; (2) determine if additional commercial tourniquets warrant CoTCCC recommendation; and (3) identify commercial tourniquets that require further development, or which tourniquets do not currently warrant recommendation based on the study criteria. Additionally this evaluation desired to establish a preferred features guideline for the research, development, and testing of limb tourniquets. Finally, CoTCCC wanted to establish a model for future reviews of CoTCCC-recommended devices and products on a recurring basis"
Notes[edit | edit source]
- Criteria applied in determining which to reccomend:
- Arterial occlusion
- Time of application
- Time of occlusion < 60 seconds
- Time to complete < 90 seconds
- Simplicity of application
- Usability/easy of use
- Steps to complete
- Pressure
- Achieve initial occlusion
- Point of harm
- Tourniquet specifications
- Width
- Length
- Locking mechanism
- Time recording
- Weight
- Complications and Safety
- Reported failures/problems
- Safety Issues
- Usage reports
- Combat usage reports
- Civilian usage reports
- User preferences
- Logistics
- National Stock Number (NSN)
- Government Service Administration (GSA) cost per unit
- Commercial cost per unit
- Specifics about the criteria not given:(
Comparison of Two Tourniquets on a Mid-Thigh Model: The Israeli Silicone Stretch and Wrap Tourniquet vs. The Combat Application Tourniquet[edit | edit source]
Glick, C. Y., Furer, M. A., Glassberg, C. E., Sharon, R., & Ankory, M. R. (2018). Comparison of Two Tourniquets on a Mid-Thigh Model: The Israeli Silicone Stretch and Wrap Tourniquet vs. The Combat Application Tourniquet. Military Medicine, 183(suppl_1), 157–161. https://doi.org/10.1093/milmed/usx169
Introduction[edit | edit source]
"Experience from recent conflicts underlines the dramatic impact of effective tourniquet use on combat casualty mortality. Although the Combat Application Tourniquet (CAT) is replacing the silicone band tourniquets (IST; "Israeli Silicone Tourniquet") in the Israeli Defense Forces, no direct comparison was made between them. The purpose of this study is to compare the performance of the two tourniquets on a mid-thigh model."
Notes[edit | edit source]
- Study performed on manikins
- Successful application considered reaching 200 mmHg, does not provide upper limit
- mid-thigh application
Evaluation of the Esmark Bandage as a Tourniquet for Forefoot Surgery[edit | edit source]
Grebing, B. R., & Coughlin, M. J. (2004). Evaluation of the Esmark Bandage as a Tourniquet for Forefoot Surgery. Foot & Ankle International, 25(6), 397–405. https://doi.org/10.1177/107110070402500606
Abstract[edit | edit source]
"Purpose: Although used routinely as a tourniquet in forefoot surgery, the pressure under an Esmark bandage has had little evaluation, and its use has been discouraged by some. The purpose of this study was to quantitate the pressure generated by an elastic bandage in a clinical setting and compare several different types of commercially available Esmark bandages."
Notes[edit | edit source]
- Discusses calibration and measuring pressure using blood pressure cuffs
- Cites other research discussing appropriate pressures for tourniquets:
- 219 - 250 mm Hg, more for older patients and people with hypertension
- Safe and effective pressure is 150 mm Hg above systolic pressure
- More than 500 mmHg can cause damage
- 222 mm Hg avg. lead to some breakthrough bleeding, 288 mm Hg eliminates most breakthrough bleeding
Digital Tourniquets: A Pressure Study with Clinical Relevance[edit | edit source]
Hixson, F. Peter, et al. "Digital Tourniquets: A Pressure Study with Clinical Relevance." The Journal of Hand Surgery, vol. 11, no. 6, 1986, pp. 865–68, https://doi.org/10.1016/S0363-5023(86)80239-8.
Abstract[edit | edit source]
"This study measured the pressures under the three most commonly used digital tourniquets - the Penrose drain, the rolled rubber glove, and the rubber band. A miniature pressure transducer and a digital strain indicator were used to measure pressures generated by the various tourniquets. The rolled rubber glove technique was highly consistent, irrespective of the clinical experience of the subject, and uniformly generated pressures of less than 500 mm Hg. Pressures generated by Penrose drains and rubber bands were highly variable and were significantly greater than 500 mm Hg. The so-called calibrated Penrose drain generated the highest pressures in the study. The relationship between tourniquet pressures and neurovascular injury in the human digit is not clearly defined."
Notes[edit | edit source]
- Used pressure transducer
- Target pressure <500 mm Hg
2019 Recommended Limb Tourniquets in Tactical Combat Casualty Care.[edit | edit source]
Montgomery, Harold R., et al. "2019 Recommended Limb Tourniquets in Tactical Combat Casualty Care." Journal of Special Operations Medicine: A Peer Reviewed Journal for SOF Medical Professionals, vol. 19, no. 4, 2019, pp. 27–50.
Abstract[edit | edit source]
"Military and civilian trauma can be distinctly different but the leading cause of preventable trauma deaths in the prehospital environment, extremity hemorrhage, does not discriminate. The current paper is the most comprehensive review of limb tourniquets employable in the tactical combat casualty care environment and provides the first update to the CoTCCC-recommended limb tourniquets since 2005. This review also highlights the lack of unbiased data, official reporting mechanisms, and official studies with established criteria for evaluating tourniquets. Upon review of the data, the CoTCCC voted to update the recommendations in April 2019."
Notes[edit | edit source]
- Done by organization whose approval is widely valued
- To determine which to recommend, tourniquets were evaluated based on these criteria, see what tester/trainer can measure
Scoring Criteria:
- Arterial occlusion was the most critical score as a limb tourniquet must adequately demonstrate that it can effectively occlude arterial blood flow of an extremity.
- Speed of application to achieve initial occlusion <60 seconds.
- Tester/trainer should measure time to apply as well
- The simplicity of application was determined as a combination of how easily the device can be applied, how many steps are required for application and/or the number of twists, turns, clicks or pumps necessary to achieve occlusion.
- Within optimal occlusion pressure range of 180 and 500mmHg. ***
- Specifications of ≥1.5 inches wide, ≥37.50 inches in length, a locking mechanism, time recording area, and weight <8 ounces.
- Known reported or published complications, failures, or safety issues of devices.
- Combat usage reports, civilian usage reports and user preferences in published literature; and logistics data.
Initial Tourniquet Pressure Does Not Affect Tourniquet Arterial Occlusion Pressure[edit | edit source]
Slaven, Sean E., et al. "Initial Tourniquet Pressure Does Not Affect Tourniquet Arterial Occlusion Pressure." Journal of Special Operations Medicine: A Peer Reviewed Journal for SOF Medical Professionals, vol. 15, no. 1, 2015, pp. 39–49.
Abstract[edit | edit source]
Background[edit | edit source]
"Effective nonelastic strap-based tourniquets are typically pulled tight and friction or hook-and-loop secured before engaging a mechanical advantage system to reach arterial occlusion pressure. This study examined the effects of skin surface initial secured pressure (Friction Pressure) on the skin surface pressure applied at arterial occlusion (Occlusion Pressure) and on the use of the mechanical advantage system."
Notes[edit | edit source]
- Initial pressure unimportant in what final pressure should be, does affect how many turns/how much tightening is needed
- Occlusion pressures:
- CAT (Median, Min-Max) -- 318mmHg, 260-536 mmHg
- RMT(Median, Min-Max) -- 328 mmHg, 160-472 mmHg
From Pull to Pressure: Effects of Tourniquet Buckles and Straps[edit | edit source]
Valliere, Michael J., et al. "From Pull to Pressure: Effects of Tourniquet Buckles and Straps." Journal of the American College of Surgeons, vol. 227, no. 3, 2018, pp. 332–45, https://doi.org/10.1016/j.jamcollsurg.2018.06.005.
Background[edit | edit source]
"Limb tourniquet pressures > 100 mmHg before tightening system use eases achieving arterial occlusion, minimizes tightening system problems, and probably minimizes discomfort. This study examined effects of buckle and strap features on converting pulling force to strap pressure."
Notes[edit | edit source]
- From background - pressures >100 mmHg before tightening is good, > 150 mmHg better, maybe implement a way of measuring this in trainer.
Tourniquet Pressures: Strap Width and Tensioning System Widths[edit | edit source]
Wall, Piper L., Ohmar Coughlin, et al. "Tourniquet Pressures: Strap Width and Tensioning System Widths." Journal of Special Operations Medicine: A Peer Reviewed Journal for SOF Medical Professionals, vol. 14, no. 4, 2014, pp. 19–29.
Background[edit | edit source]
Pressure distribution over tourniquet width is a determinant of pressure needed for arterial occlusion. Different width tensioning systems could result in arterial occlusion pressure differences among nonelastic strap designs of equal width.
Notes[edit | edit source]
- Do not have access to full article
- Narrower tensioning systems lose less pressure over time
- Muscles relaxing and time can reduce pressure from non-elastic tourniquets -- Maybe measure pressure over time from tourniquets as well
Tourniquets and Occlusion: The Pressure of Design[edit | edit source]
Wall, Piper L., David C. Duevel, et al. "Tourniquets and Occlusion: The Pressure of Design." Military Medicine, vol. 178, no. 5, 2013, pp. 578–87, https://doi.org/10.7205/MILMED-D-12-00490.
Abstract[edit | edit source]
"Nerve injuries result from tourniquet pressure. The objective was to determine arterial occlusion and completion pressures with the 3.8-cm-wide windlass Combat Application Tourniquet (CAT) and the 10.4-cm-wide Stretch, Wrap, and Tuck Tourniquet (SWAT-T). Methods: Sixteen volunteers self-applied and had tourniquets applied to their thighs and arms (CAT and SWAT-T, random order, then blood pressure cuffs). Results: Occlusion (Doppler signal elimination) pressures were higher than predicted (p < 0.0001), highest with the CAT (p < 0.0001), and often lower than completion pressures (completion median, range: CAT 360, 147–745 mm Hg; SWAT-T 290, 136–449 mm Hg; cuff 184, 108–281 mm Hg). Three CAT thigh and 9 CAT arm completion pressures were >500 mm Hg. Pressure decreases and occlusion losses occurred over 1 minute (pressure decrease: CAT 44 ± 33 mm Hg; SWAT-T 6 ± 8 mm Hg; cuff 14 ± 19 mm Hg; p < 0.0001; loss/initially occluded: CAT 17 of 61, SWAT-T 5 of 61, cuff 40 of 64, p < 0.01). CAT pressures before turn did not have a clear relationship with turns to occlusion. Conclusions: Limb circumference/tourniquet width occlusion pressure predictions are not good substitutes for measurements. The wider SWAT-T has lower occlusion and completion pressures than the CAT. Decreases in muscle tension lead to decreases in tourniquet pressure, especially with the nonelastic CAT, which can lead to occlusion loss."
Notes[edit | edit source]
- Larger Tourniquet strap width means lower occlusion pressure, but predictions about occlusion pressure based on width are not good
- No tourniquet pressure or occlusion differences between male and female patients
- Higher occlusion/completion pressures means it is less likely for occlusion to be lost over time for non-elastic - not consistent enough to make predictions.
- If this happens, another tourniquet should be applied, rather than tightening the already applied one
- The two articles above focus on strap width, since our strap width will be different, we can use these to figure out generally how tight ours needs to be.
Ukrainian Volunteers Use 3D Printers to Save Lives[edit | edit source]
Mykhailyshyn, R. (2022, June 2). Ukrainian Volunteers Print Bandages, Tourniquets, and Periscopes for Fighters on the Frontlines. IEEE Spectrum. https://spectrum.ieee.org/ukraine-3d-printing
Notes[edit | edit source]
- Over pandemic, communication systems developed to help get 3D printed gear to people that need it
- CAT tourniquets in short supply in Ukraine, when this was found out, designs and improvements to designs came quickly
- Supply of uncommon filaments is an issue
- Because of these networking systems, 3D printing is fast and responsive way to get tools needed to people who need them
Tourniquets in orthopedic surgery[edit | edit source]
Sharma, J. P., & Salhotra, R. (2012). Tourniquets in orthopedic surgery. Indian Journal of Orthopaedics, 46(4), 377–383. https://doi.org/10.4103/0019-5413.98824
Abstract[edit | edit source]
"Tourniquets are commonly used in limb surgeries, be it orthopedic or plastic surgeries. But the inflation pressures, the duration, and release guidelines are still not clear. According to a survey, majority of orthopedic surgeons inflate the tourniquet to fixed pressures for the upper and the lower limbs without considering the baseline blood pressure of the patient on whom the tourniquets are being applied. This review was designed to recall and review the safe use of tourniquets and the various techniques that can be employed to minimize the complications of tourniquet use. Google, science direct, and pubmed were searched for appropriate literature and relevant articles were identified."
Notes[edit | edit source]
- Focus on pneumatic tourniquets, which are likely wider than ours - pressures will be lower, other than that should carry over
- Nerve injury risk if pressure too high, blood loss risk if pressure too low
- safe duration and pressure of tourniquets controversial, no guidelines laid out
- Surgeons generally use fixed pressures - 250 mmHg for arm and 300 mmHg for thigh - or +100 mmHg above sytolic arm & +100-150 mmHg above sys. thigh
- Not recommended because d consider age and first does not consider Blood pressure
- Younger people have lower sys BP so pressure should be lower
- Recommended that users use the lowest effective pressure, using other techniques/technology to find what that is
- In our case, will need to find fixed pressures
- Levy et al. (1993) says average effective tourniquet pressure for upper arm is 202.3 +-34.2 mmHg
Levy O, David Y, Heim M, Eldar I, Chetrit A, Engel J. Minimal tourniquet pressure to maintain arterial closure in upper limb surgery. J Hand Surg Br. 1993;18:204–6.
- From Burner's 10 rules for tourniquet usage - pressure:
- arm: 10cm width - 50-100 mmHg above systolic, or 200-250 mmHg
- thigh: 15cm width - double systolic or 250-300 mmHg
- wider cuffs recommended for larger limbs, rather than increasing pressure (maybe use 2 because width is fixed?)
Kutty S, McElwain JP. Padding under tourniquets in tourniquet controlled surgery: Bruner's ten rules revisited. Injury. 2002;33:75.
Quantifying the Elastic Property of Nine Thigh Muscles Using Magnetic Resonance Elastography[edit | edit source]
Chakouch MK, Charleux F, Bensamoun SF (2015) Quantifying the Elastic Property of Nine Thigh Muscles Using Magnetic Resonance Elastography. PLoS ONE 10(9): e0138873. doi:10.1371/journal.pone.0138873
Abstract[edit | edit source]
"Background: Pathologies of the muscles can manifest different physiological and functional changes. To adapt treatment, it is necessary to characterize the elastic property (shear modulus) of single muscles. Previous studies have used magnetic resonance elastography (MRE), a technique based on MRI technology, to analyze the mechanical behavior of healthy and pathological muscles. The purpose of this study was to develop protocols using MRE to determine the shear modulus of nine thigh muscles at rest. Methods: Twenty-nine healthy volunteers (mean age = 26 ± 3.41 years) with no muscle abnormalities underwent MRE tests (1.5 T MRI). Five MRE protocols were developed to quantify the shear moduli of the nine following thigh muscles at rest: rectus femoris (RF), vastus medialis (VM), vastus intermedius (VI), vastus lateralis (VL), sartorius (Sr), gracilis (Gr), semimembranosus (SM), semitendinosus (ST), and biceps (BC). In addition, the shear modulus of the subcutaneous adipose tissue was analyzed. Results: The gracilis, sartorius, and semitendinosus muscles revealed a significantly higher shear modulus (μ_Gr = 6.15 ± 0.45 kPa, μ_ Sr = 5.15 ± 0.19 kPa, and μ_ ST = 5.32 ± 0.10 kPa, respectively) compared to other tissues (from μ_ RF = 3.91 ± 0.16 kPa to μ_VI = 4.23 ± 0.25 kPa). Subcutaneous adipose tissue had the lowest value (μ_adipose tissue = 3.04 ± 0.12 kPa) of all the tissues tested. Conclusion: The different elasticities measured between the tissues may be due to variations in the muscles' physiological and architectural compositions. Thus, the present protocol could be applied to injured muscles to identify their behavior of elastic property. Previous studies on muscle pathology found that quantification of the shear modulus could be used as a clinical protocol to identify pathological muscles and to follow-up effects of treatments and therapies. These data could also be used for modelling purposes."
Notes[edit | edit source]
- Shear modulus varies throughtout leg
- I believe shear is what I am looking for, tensile/compression would be towards foot/up through body direction. TPU also shear since layers of plastic will be horizontal accross and force will be applied normal to length - shear is torque and thats not is. need bulk modulus...
- Going to average these values to find shear modulus of whole leg, and try to replicate that with TPU
All in kPa:
- GR: 6.15 +/- 0.45
- SR 5.15 +/- 0.19
- ST: 5.32 +/- 0.1
- 5 within range of 3.91 +/- 0.16 to 4.23 +/-0.25
- adipose tissue: 3.04 +/- 0.12
- Avg.: 4.45 kPa
- Yea this actually isnt useful to us
