Haemodynamic Physiology
Conditions
Keywords
Haemodynamic physiology
Brief summary
The most efficient way of electrically stimulating the calf muscles has not been identified. The investigators aim to investigate this using a matrix of electrical parameters, and measuring the outcome with vascular ultrasound of the leg.
Detailed description
Blood is aided on its journey to the heart by the action of the muscles of the legs. Muscle contraction squeezes the deep veins of the leg and pushes blood upwards, back towards the heart. In immobilised patients, or those with blood vessel problems, the pumping process can be helped by machines that either squeeze or shock the muscles of the calf (e.g. intermittent pneumatic compression, electrical stimulating devices). Many are licensed for medical use, and some are common place in hospitals and outpatient departments.
Interventions
DEVICEElectrical stimulation (Digitimer)
Stimulation with Digitimer (DS7A HV, Digitimer Ltd, UK) over motor point of muscle in protocol. 1Hz, pulse duration 1ms, maximum compliance voltage 200V. Current set to twice motor threshold
Sponsors
Imperial College London
Study design
Allocation
NON_RANDOMIZED
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* 18 years or older * Current good health
Exclusion criteria
* History of cardiovascular disease * Ankle Brachial Pressure Index \<0.9 * Venous reflux\>0.5s * Pregnancy
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Venous Haemodynamic Measurements (Volume Flow Rate) | Baseline compared to that after 10-mins stimulation (2-mins to take measurements) | Measurement by ultrasound, in right femoral vein. Flow rate (ml/min). |
| Venous Haemodynamic Measurements (Time Averaged Maximum Velocity) | Baseline compared to that after 10-mins stimulation (2-mins to take measurements) | Measurement by ultrasound, in right femoral vein. Time averaged maximum velocity (cm/s). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Pain Grading on Stimulation | During stimulation (10-mins each muscle) | Visual analogue scale (0-minimum pain, to 100-maximum pain) |
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Electrical Muscle Stimulation Participants All participants for electrical stimulation of respective muscles (tibialis anterior, peroneus longus, gastrocnemius, vastus lateralis, rectus femoris, vastus medialis) | 12 |
| Total | 12 |
Baseline characteristics
| Characteristic | Electrical Muscle Stimulation Participants |
|---|---|
| Age, Continuous | 23.1 years STANDARD_DEVIATION 3 |
| Body mass index | 23.1 kg/m^2 STANDARD_DEVIATION 3 |
| Region of Enrollment United Kingdom | 12 participants |
| Sex: Female, Male Female | 7 Participants |
| Sex: Female, Male Male | 5 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | 0 / 12 |
| other Total, other adverse events | 0 / 12 |
| serious Total, serious adverse events | 0 / 12 |
Outcome results
Primary
Venous Haemodynamic Measurements (Time Averaged Maximum Velocity)
Measurement by ultrasound, in right femoral vein. Time averaged maximum velocity (cm/s).
Time frame: Baseline compared to that after 10-mins stimulation (2-mins to take measurements)
Population: Muscle stimulated
| Arm | Measure | Group | Value (MEDIAN) | Dispersion |
|---|---|---|---|---|
| Vastus Lateralis | Venous Haemodynamic Measurements (Time Averaged Maximum Velocity) | Baseline | 8.2 cm/s | Standard Deviation 10 |
| Vastus Lateralis | Venous Haemodynamic Measurements (Time Averaged Maximum Velocity) | Stimulation | 8.2 cm/s | Standard Deviation 15 |
| Rectus Femoris | Venous Haemodynamic Measurements (Time Averaged Maximum Velocity) | Baseline | 8.8 cm/s | Standard Deviation 14 |
| Rectus Femoris | Venous Haemodynamic Measurements (Time Averaged Maximum Velocity) | Stimulation | 10.6 cm/s | Standard Deviation 10 |
| Vastus Medialis | Venous Haemodynamic Measurements (Time Averaged Maximum Velocity) | Baseline | 11.3 cm/s | Standard Deviation 10 |
| Vastus Medialis | Venous Haemodynamic Measurements (Time Averaged Maximum Velocity) | Stimulation | 10.9 cm/s | Standard Deviation 8 |
| Gastrocnemius (Medial) | Venous Haemodynamic Measurements (Time Averaged Maximum Velocity) | Baseline | 8.5 cm/s | Standard Deviation 12 |
| Gastrocnemius (Medial) | Venous Haemodynamic Measurements (Time Averaged Maximum Velocity) | Stimulation | 11.6 cm/s | Standard Deviation 19 |
| Gastrocnemius (Lateral) | Venous Haemodynamic Measurements (Time Averaged Maximum Velocity) | Baseline | 7.5 cm/s | Standard Deviation 12 |
| Gastrocnemius (Lateral) | Venous Haemodynamic Measurements (Time Averaged Maximum Velocity) | Stimulation | 10.5 cm/s | Standard Deviation 11 |
| Tibialis Anterior | Venous Haemodynamic Measurements (Time Averaged Maximum Velocity) | Baseline | 11.3 cm/s | Standard Deviation 13 |
| Tibialis Anterior | Venous Haemodynamic Measurements (Time Averaged Maximum Velocity) | Stimulation | 12 cm/s | Standard Deviation 9 |
| Peroneus Longus | Venous Haemodynamic Measurements (Time Averaged Maximum Velocity) | Baseline | 13.4 cm/s | Standard Deviation 14 |
| Peroneus Longus | Venous Haemodynamic Measurements (Time Averaged Maximum Velocity) | Stimulation | 10.8 cm/s | Standard Deviation 17 |
p-value: <0.05Wilcoxan signed-rank test
Primary
Venous Haemodynamic Measurements (Volume Flow Rate)
Measurement by ultrasound, in right femoral vein. Flow rate (ml/min).
Time frame: Baseline compared to that after 10-mins stimulation (2-mins to take measurements)
Population: Muscle stimulated
| Arm | Measure | Group | Value (MEDIAN) | Dispersion |
|---|---|---|---|---|
| Vastus Lateralis | Venous Haemodynamic Measurements (Volume Flow Rate) | Baseline | 119 ml/min | Standard Deviation 67 |
| Vastus Lateralis | Venous Haemodynamic Measurements (Volume Flow Rate) | Stimulation | 148 ml/min | Standard Deviation 97 |
| Rectus Femoris | Venous Haemodynamic Measurements (Volume Flow Rate) | Baseline | 158 ml/min | Standard Deviation 123 |
| Rectus Femoris | Venous Haemodynamic Measurements (Volume Flow Rate) | Stimulation | 158 ml/min | Standard Deviation 123 |
| Vastus Medialis | Venous Haemodynamic Measurements (Volume Flow Rate) | Baseline | 158 ml/min | Standard Deviation 134 |
| Vastus Medialis | Venous Haemodynamic Measurements (Volume Flow Rate) | Stimulation | 150 ml/min | Standard Deviation 125 |
| Gastrocnemius (Medial) | Venous Haemodynamic Measurements (Volume Flow Rate) | Baseline | 144 ml/min | Standard Deviation 100 |
| Gastrocnemius (Medial) | Venous Haemodynamic Measurements (Volume Flow Rate) | Stimulation | 178 ml/min | Standard Deviation 120 |
| Gastrocnemius (Lateral) | Venous Haemodynamic Measurements (Volume Flow Rate) | Baseline | 161 ml/min | Standard Deviation 168 |
| Gastrocnemius (Lateral) | Venous Haemodynamic Measurements (Volume Flow Rate) | Stimulation | 114 ml/min | Standard Deviation 205 |
| Tibialis Anterior | Venous Haemodynamic Measurements (Volume Flow Rate) | Baseline | 164 ml/min | Standard Deviation 66 |
| Tibialis Anterior | Venous Haemodynamic Measurements (Volume Flow Rate) | Stimulation | 153 ml/min | Standard Deviation 171 |
| Peroneus Longus | Venous Haemodynamic Measurements (Volume Flow Rate) | Baseline | 139 ml/min | Standard Deviation 135 |
| Peroneus Longus | Venous Haemodynamic Measurements (Volume Flow Rate) | Stimulation | 149 ml/min | Standard Deviation 113 |
p-value: <0.05Wilcoxan signed-rank test
Secondary
Pain Grading on Stimulation
Visual analogue scale (0-minimum pain, to 100-maximum pain)
Time frame: During stimulation (10-mins each muscle)
Population: Muscle stimulated
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Vastus Lateralis | Pain Grading on Stimulation | 15 scores on a scale | Standard Deviation 1 |
| Rectus Femoris | Pain Grading on Stimulation | 66.3 scores on a scale | Standard Deviation 1 |
| Vastus Medialis | Pain Grading on Stimulation | 21.3 scores on a scale | Standard Deviation 1 |
| Gastrocnemius (Medial) | Pain Grading on Stimulation | 28.8 scores on a scale | Standard Deviation 1 |
| Gastrocnemius (Lateral) | Pain Grading on Stimulation | 31.3 scores on a scale | Standard Deviation 1 |
| Tibialis Anterior | Pain Grading on Stimulation | 21.3 scores on a scale | Standard Deviation 1 |
| Peroneus Longus | Pain Grading on Stimulation | 30 scores on a scale | Standard Deviation 1 |