Hemorrhage, Vascular Injury
Conditions
Keywords
tourniquet, arterial, pre-hospital, SOFTT-W, Battle Wrap, windlass, exsanguination, hemorrhage, amputation
Brief summary
This cross-over study of twenty five (anticipated) healthy human subjects will utilize two active control devices, and two different widths of the investigational device. One active control is representative of the usual care tourniquet applied in hospital settings. The second active control is a windlass tourniquet representative of the pre-hospital and military usual care tourniquet device. Two inch and four inch widths of the investigational device will be evaluated. The purpose of this study is to characterize and compare investigational and control tourniquet safety and efficacy. All tourniquets will be applied to the upper thigh. Efficacy data is provided by the presence or absence of popliteal flow when assessed with ultrasound. Mapping of interface pressures between the skin and the tourniquet will provide safety data. A minimum washout of five minutes will be allowed between tourniquet applications. All interventions will be applied in one visit. No follow up visit is anticipated.
Detailed description
This is a small study of 19 participants conducted over only two days. All data for this study is collected by the study. Tourniquet application: All tourniquet applications conducted with the participant seated on the edge of an exam table with one leg hanging off the side, and the leg for tourniquet application extended outward, with the mid calf resting on a support. This position permits access to the popliteal artery for ultrasonography while the investigator has access to apply the tourniquet. The lower edge of each tourniquet is aligned just above the middle of the thigh. All tourniquets are applied over the pressure mapping sensor. The sensor is slightly thicker than denim jeans. Extra care must be taken to ensure that the material of the sensor does not interfere with removing the slack from the windlass tourniquets before turning the windlass to apply final pressure. When a second windlass tourniquet is to be applied it is applied just above or proximal to the first windlass tourniquet. The windlass of each tourniquet are located as far from each other as possible. Meaning that if the windlass of the first tourniquet is the twelve o'clock position then the windlass of the second tourniquet is positioned at the six o'clock position. The strap of each tourniquet cannot slip over the windlass of the other. This 6 and 12 positioning prevents the strap of the second windlass tourniquet from slipping over the first as it is tightened. When the tape tourniquet is applied, it is elongated, stretched as it is layered over the preceding layer with at least one half over lap. The tape tourniquet used in this study is similar to, but not the same as the product called manufactured by Entrotech, called Battle Wrap. Results similar to this study should not be expected with the Battle Wrap product.
Interventions
DEVICEPneumatic Tourniquet
Automated pneumatic tourniquet, applied to middle upper thigh.
DEVICEOne Windlass Tourniquet
One Windlass Tourniquet 3.8 cm (1.5 inch) wide. A Special Operations Forces Tactical Tourniquet Wide (SOFTT-W) will be used for the windlass tourniquet. One windlass tourniquet will be applied to the middle upper thigh.
DEVICETwo Windlass Tourniquets
Two Windlass Tourniquets will be applied by applying a second 3.8 cm (1.5 inch) wide windlass tourniquet immediately proximal to the first windlass tourniquet.
DEVICETourniquet Tape 5 cm
Tourniquet Tape is 5 cm (2 inch) in width. Tourniquet Tape is a highly elastic transparent occlusive material that can create circumferential pressure when stretched and wrapped around a limb. The tape should be stretched and overlapped by at least half the width as it is applied. The final wrap should be applied without tension.
DEVICETourniquet Tape 10 cm
Tourniquet Tape is 10 cm (4 inch) in width. Tourniquet Tape is a highly elastic transparent occlusive material that can create circumferential pressure when stretched and wrapped around a limb. The tape should be stretched and overlapped by at least half the width as it is applied. The final wrap should be applied without tension.
Sponsors
Mercy Health
Marcus Migura
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
SINGLE (Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 55 Years
Healthy volunteers
Yes
Inclusion criteria
1. Upper thigh circumference greater than 61 cm or 24 inches. 2. Upper thigh circumference greater than the 50th percentile based on available anthropometric data.
Exclusion criteria
1. Currently taking medications for the treatment of hypertension. 2. Cardiac, renal, pulmonary, hepatic or hemologic disease or disorder. 3. Patients with signs or symptoms of vascular insufficiency. Specifically, patients with any history of non-healing wound, ulcer, blood clots or peripheral vascular disease will be excluded. 4. Any coagulation disorder, prior thrombotic or embolic events such as a deep vein thrombosis. 5. Sickle cell. 6. Diabetes mellitus 7. Rheumatic arthritis or other auto immune disease. 8. Major surgery, significant traumatic injury, within 60 days trial. 9. Skin grafts on lower extremities. 10. Known or observed neurological symptoms, to include peripheral neurological symptoms or deficits. 11. Pregnant women, and women who suspect themselves to be pregnant are not eligible for this study. 12. Any known malignancy. 13. Claudication
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Radiologist Limb Occlusion Assessment | For 1 sustained minute after application of each tourniquet intervention. | Duplex and color flow ultrasound are used to assess distal blood flow at the popliteal artery for 1 sustained minute following the application of a each tourniquet intervention to the middle upper thigh. If no flow is observed for 1 sustained minute then it is considered successful occlusion. A still image is then saved for later evaluation by the blinded outcome assessor. The 5 cm tape was discontinued after the 4th participant because the tape was considered to unacceptably narrow after stretching and this was considered a mechanical failure even if occlusion was observed. Therefore the 5 cm tape data was not evaluated by the radiologist. |
| Investigator Limb Occlusion Assessment | For 1 sustained minute after application of each tourniquet intervention. | Duplex and color flow ultrasound are used to assess distal blood flow at the popliteal artery for 1 sustained minute following the application of each tourniquet intervention to the middle upper thigh. If no flow is observed for 1 sustained minute then it is considered a successful occlusion. This assessment was made by the investigator and ultrasonographer applying the intervention. |
Countries
United States
Participant flow
Recruitment details
Healthy volunteers with a minimum upper thigh circumference of 61 cm were recruited from the general population during the first two weeks of December 2015.
Pre-assignment details
Each participant receives a different intervention each period. 19 Participants randomly allocated to unique sequences of four interventions. No participants were lost once enrolled. 5 minute minimum washout period between interventions.
Participants by arm
| Arm | Count |
|---|---|
| One Windlass Tourniquet Baseline characteristics for participants that received only one windlass tourniquet. | 8 |
| Two Windlass Tourniquets Baseline characteristics for participants who had a second windlass tourniquet applied immediately proximal to the first. Meaning that a single windlass tourniquet did not appear effective. | 11 |
| Total | 19 |
Baseline characteristics
| Characteristic | One Windlass Tourniquet | Two Windlass Tourniquets | Total |
|---|---|---|---|
| Age, Continuous | 30.5 years STANDARD_DEVIATION 9.5 | 36.1 years STANDARD_DEVIATION 8.8 | 33.7 years STANDARD_DEVIATION 9.25 |
| Ankle Brachial Index (ABI) | 1.15 Ratio STANDARD_DEVIATION 0.08 | 1.16 Ratio STANDARD_DEVIATION 0.11 | 1.16 Ratio STANDARD_DEVIATION 0.09 |
| BMI Weight Status Category (CDC) BMI 18.5 - 24.9 Normal | 1 Participants | 0 Participants | 1 Participants |
| BMI Weight Status Category (CDC) BMI 25.0 - 29.9 Overweight | 7 Participants | 1 Participants | 8 Participants |
| BMI Weight Status Category (CDC) BMI 30.0 and Above Obese | 0 Participants | 10 Participants | 10 Participants |
| Body Mass Index (BMI) | 27.4 Kg/m^2 STANDARD_DEVIATION 1.7 | 36.1 Kg/m^2 STANDARD_DEVIATION 4.3 | 32.4 Kg/m^2 STANDARD_DEVIATION 5.6 |
| Height | 178.6 cm STANDARD_DEVIATION 9.7 | 175.0 cm STANDARD_DEVIATION 10.1 | 176.5 cm STANDARD_DEVIATION 9.8 |
| Limb Occlusion Pressure | 280 mmHg STANDARD_DEVIATION 30 | 319 mmHg STANDARD_DEVIATION 44 | 302 mmHg STANDARD_DEVIATION 43 |
| Percentile of Mean Thigh Circumference Lower thigh circumference percentile | 75 Percentile | 95 Percentile | 90 Percentile |
| Percentile of Mean Thigh Circumference Upper thigh circumference percentile | 65 Percentile | 95 Percentile | 90 Percentile |
| Sex: Female, Male Female | 0 Participants | 4 Participants | 4 Participants |
| Sex: Female, Male Male | 8 Participants | 7 Participants | 15 Participants |
| Systolic Blood Pressure (SBP) | 130 mmHg STANDARD_DEVIATION 8.8 | 136 mmHg STANDARD_DEVIATION 10.4 | 133 mmHg STANDARD_DEVIATION 10 |
| Thigh Circumference 10 cm above Mid Thigh | 61.0 cm STANDARD_DEVIATION 4 | 68.7 cm STANDARD_DEVIATION 5.7 | 65.4 cm STANDARD_DEVIATION 6.3 |
| Thigh Circumference Lower Thigh | 42.3 cm STANDARD_DEVIATION 4.4 | 45.8 cm STANDARD_DEVIATION 3.1 | 44.3 cm STANDARD_DEVIATION 4 |
| Thigh Circumference Middle Thigh | 55 cm STANDARD_DEVIATION 4.2 | 60.3 cm STANDARD_DEVIATION 5.3 | 58.1 cm STANDARD_DEVIATION 5.5 |
| Thigh Circumference Upper Thigh | 63.5 cm STANDARD_DEVIATION 3.7 | 71.2 cm STANDARD_DEVIATION 5.9 | 68.0 cm STANDARD_DEVIATION 6.3 |
| Weight | 87.5 kg STANDARD_DEVIATION 11 | 111.3 kg STANDARD_DEVIATION 21.5 | 101.25 kg STANDARD_DEVIATION 21.22 |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk | EG003 affected / at risk |
|---|---|---|---|---|
| deaths Total, all-cause mortality | 0 / 19 | 0 / 19 | 0 / 4 | 0 / 19 |
| other Total, other adverse events | 0 / 19 | 0 / 19 | 0 / 4 | 0 / 19 |
| serious Total, serious adverse events | 0 / 19 | 0 / 19 | 0 / 4 | 0 / 19 |
Outcome results
Primary
Investigator Limb Occlusion Assessment
Duplex and color flow ultrasound are used to assess distal blood flow at the popliteal artery for 1 sustained minute following the application of each tourniquet intervention to the middle upper thigh. If no flow is observed for 1 sustained minute then it is considered a successful occlusion. This assessment was made by the investigator and ultrasonographer applying the intervention.
Time frame: For 1 sustained minute after application of each tourniquet intervention.
| Arm | Measure | Group | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Tourniquet Tape 10 cm | Investigator Limb Occlusion Assessment | Success: Absent flow observed by investigator. | 19 Participants |
| Tourniquet Tape 10 cm | Investigator Limb Occlusion Assessment | Failure: Flow observed by investigator. | 0 Participants |
| Pneumatic Tourniquet | Investigator Limb Occlusion Assessment | Success: Absent flow observed by investigator. | 19 Participants |
| Pneumatic Tourniquet | Investigator Limb Occlusion Assessment | Failure: Flow observed by investigator. | 0 Participants |
| One Windlass Tourniquet | Investigator Limb Occlusion Assessment | Success: Absent flow observed by investigator. | 8 Participants |
| One Windlass Tourniquet | Investigator Limb Occlusion Assessment | Failure: Flow observed by investigator. | 11 Participants |
| Two Windlass Tourniquets | Investigator Limb Occlusion Assessment | Failure: Flow observed by investigator. | 2 Participants |
| Two Windlass Tourniquets | Investigator Limb Occlusion Assessment | Success: Absent flow observed by investigator. | 9 Participants |
| Tourniquet Tape 5 cm | Investigator Limb Occlusion Assessment | Success: Absent flow observed by investigator. | 3 Participants |
| Tourniquet Tape 5 cm | Investigator Limb Occlusion Assessment | Failure: Flow observed by investigator. | 1 Participants |
Primary
Radiologist Limb Occlusion Assessment
Duplex and color flow ultrasound are used to assess distal blood flow at the popliteal artery for 1 sustained minute following the application of a each tourniquet intervention to the middle upper thigh. If no flow is observed for 1 sustained minute then it is considered successful occlusion. A still image is then saved for later evaluation by the blinded outcome assessor. The 5 cm tape was discontinued after the 4th participant because the tape was considered to unacceptably narrow after stretching and this was considered a mechanical failure even if occlusion was observed. Therefore the 5 cm tape data was not evaluated by the radiologist.
Time frame: For 1 sustained minute after application of each tourniquet intervention.
Population: One ultrasound image from one of the participants of the pneumatic tourniquet (ATS) group failed to capture anatomy and was therefore not included in the analysis.~One ultrasound image from one of the participants of the windlass tourniquet (SOFTT-W) group failed to capture anatomy and was therefore not included in the analysis.
| Arm | Measure | Group | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Tourniquet Tape 10 cm | Radiologist Limb Occlusion Assessment | Success: Absent flow verified by radiologist. | 19 Participants |
| Tourniquet Tape 10 cm | Radiologist Limb Occlusion Assessment | Failure: Flow verified by radiologist. | 0 Participants |
| Pneumatic Tourniquet | Radiologist Limb Occlusion Assessment | Failure: Flow verified by radiologist. | 0 Participants |
| Pneumatic Tourniquet | Radiologist Limb Occlusion Assessment | Success: Absent flow verified by radiologist. | 18 Participants |
| One Windlass Tourniquet | Radiologist Limb Occlusion Assessment | Success: Absent flow verified by radiologist. | 8 Participants |
| One Windlass Tourniquet | Radiologist Limb Occlusion Assessment | Failure: Flow verified by radiologist. | 10 Participants |
| Two Windlass Tourniquets | Radiologist Limb Occlusion Assessment | Success: Absent flow verified by radiologist. | 8 Participants |
| Two Windlass Tourniquets | Radiologist Limb Occlusion Assessment | Failure: Flow verified by radiologist. | 2 Participants |
Comparison: Null hypothesis is that one windlass tourniquet is just as likely to occlude arterial flow as the 10 cm wide tourniquet tape.~Participant count of 18 to accommodate for missing windlass tourniquet ultrasound data.p-value: 0.002McNemar
Comparison: Null hypothesis is that one windlass tourniquet is just as likely to occlude arterial flow as two windlass tourniquets.~Participant count of 18 to accommodate for missing windlass tourniquet ultrasound data.p-value: 0.008McNemar
Comparison: Null hypothesis is that the 10 cm wide tourniquet tape is just as likely to occlude arterial flow as using two windlass tourniquets.~Participant count of 18 to accommodate for missing windlass tourniquet ultrasound data.p-value: 0.5McNemar
Comparison: Null hypothesis is that using the pneumatic tourniquet is just as likely to occlude arterial flow as using two windlass tourniquets.~Participant count of 17 to accommodate for missing ultrasound data.p-value: 0.5McNemar