Blood pooling occurs when the walls and valves of veins in human legs do not work effectively, thereby making it difficult for blood to return to the heart, according to Cleveland Clinic. This condition, known as chronic venous insufficiency, causes blood to pool in veins, a condition called stasis.
Valves within veins in the legs become damaged, causing blood to leak backwards with the force of gravity instead of moving upwards. Valve damage happens due to aging, excessive sitting, extended standing and reduced mobility, notes Cleveland Clinic. Blood pressure in the affected veins remains elevated for long periods, which causes chronic venous insufficiency.
The causes of chronic venous insufficiency include blood clots, vascular deformations and pelvic tumors. Lack of blood flow or sluggish blood movement within leg veins leads to swollen legs. Other symptoms include aching legs, varicose veins, leathery-looking skin on legs, stasis ulcers and flaking skin on legs and feet. Untreated chronic venous insufficiency can lead to burst capillaries in the legs, according to Cleveland Clinic.
Dizziness may be another symptom of blood pooling in the legs. This occurs when someone suddenly stands up after sitting for long periods of time and blood pressure suddenly normalizes, notes Merck Manual. The heart rate increases, and blood vessels constrict rapidly when someone stands quickly after extended sitting.
One way to alleviate chronic venous insufficiency and blood pooling is to walk. The contraction of calf muscles during the walking motion moves blood more efficiently through the legs, according to the Society for Vascular Surgery.
WHAT IS BLOOD POOLING?
Blood pooling is a condition were blood gathers normally in the lower limb (leg), this can be for a number of reasons but can be caused by exercise. When this blood gathers in a blood vessel it places excess stress on the small values that prevent the blood being drawn back down to the feet sue to the effect of gravity.
The diagram below shows how this then places pressure on the valves, over time this will force the valves back on themselves opening the wrong way. Over time this will result in lasting damage to the valves increasing the chance of varicose veins or DVT.
As these non-return valves have an important part to play in ensuring that blood returns to the heart effectively, the posh name for this is venous return. So in terms of exercise if you have been working at an intensive level and fail to cool down effectively and fully, this will result in the build up of blood in the
limbs. This then means that the heart may not fill before each contraction, this often leads to a dizzy and faint feeling.
For these reasons it is very important that you take part in a full cool down, normally it is advised that you do some form of rhythmical exercise for 6 minutes at a low intensity. This allows the systems of the body to work to help to return the blood back to the heart. This can also be aided by a full stretching routine and partner stretches can be great for this as gravity will help to return blood back to the heart.
BLOOD POOLING — FIGHT IT!
Most people with POTS suffer from venous pooling, AKA blood pooling in their legs. It is painful! Imagine yourself jamming items into a bag. The bag stretches and stretches, and it gets heavier and heavier. In the case of venous pooling it is a similar situation. More blood is pooling in my legs than they were meant to hold. It is quite painful. I think perhaps the pain comes from my skin and muscles trying to accommodate all of the extra volume, much like that bag trying to accommodate more items than it was meant to hold. It also feels like someone strapped three pound weights to each of my legs. Each step feels heavy, as though I am walking in water up to my thighs. I know three pound weights aren’t much, but they are when I’m fatigued, my legs are already in pain, and I didn’t choose to put them there! Then there’s the appearance of venous pooling. My feet turn bright red and, after about 5 minutes or so, the veins begin to bulge. It’s not attractive. My legs aren’t the only place I feel the venous pooling. All of that blood being trapped in my legs by the pull of gravity means the rest of my body isn’t getting enough blood circulated to it, including my brain. Trust me, life is much more difficult when your brain isn’t getting enough blood!
So this is why I don’t understand why so many people with POTS choose not to wear compression stockings.
In a group of 40 patients with orthostatic intolerance due to hypotension and/or tachycardia, we have compared the pathogenetic roles of impaired contractility of the arterioles and the veins by measuring contractile responsiveness of the arterioles, reflected by increases in diastolic blood pressure and of the veins reflected by measurements of reduction in venous diameter during intravenous noradrenaline infusions.
Compared with 27 healthy subjects, patients with diffuse autonomic insufficiency showed striking supersensitivity in diastolic blood pressure (six out of eight) and venous constrictive responses (seven out of eight patients) to noradrenaline, consistent with impaired arteriolar and venous innervation.
In contrast, the patients with hyperadrenergic orthostatic hypotension (n = 16) and orthostatic tachycardia (n = 16) showed diastolic blood pressure responses to noradrenaline that were almost invariably within the 95% confidence limits of the changes in normal subjects but supersensitive constrictive responses of foot veins in 22 of 32 subjects and subnormal venous responses in two individuals. The rate of noradrenaline infusion calculated to cause 50% of maximal venous constriction (the ED50) was significantly lower in the patients [mean (SEM) 6.8 (1.9) ng/min] than in the normal subjects [mean (SEM) 23.2 (3.0) ng/min, P < 0.025].
The finding of significantly supersensitive foot vein constrictive responses to noradrenaline infusion in the patients of all three groups and supersensitive blood pressure responses exclusively in the patients with diffuse autonomic insufficiency indicates that venous pooling in the legs was the predominant pathogenetic mechanism of orthostatic intolerance in all three types of patients studied.
Correction of the orthostatic hypotension and/or tachycardia by external compression in virtually all patients confirmed this conclusion.
BLOOD POOLING IN THE LEGS MAY CAUSE VARICOSE VEINS
Blood pooling in the legs may result in varicose veins. While varicose veins are unsightly, they may also be the harbinger of worse things to come when not taken care of properly. There are treatments available for varicose veins, but they do not prevent future occurrences of varicose veins and may result in scarring.
Varicose veins form when the veins usually of the legs and the valves in the veins can no longer keep up with the demand to pump blood back to the heart. This can be from overuse of the veins and their fight against gravity of from the overproduction of blood. Overuse generally occurs in jobs that require lots of standing, like wait staff in a restaurant or nurses. Overproduction of blood normally comes during pregnancy. About three times as many women as men are affected by varicose veins. Other factors that contribute to the formation of varicose veins include obesity and genetics.
While those who are cursed by their place in the gene pool may develop varicose veins strictly through the sheer force of nature, everyone can take steps to prevent getting varicose veins. For those whose jobs require standing for long periods of times, it is important to take appropriate breaks. Those breaks should be spent off of the feet with the legs elevated to help relieve the pressure that gravity may be exerting on the veins and their valves.
Pregnant women should not eschew exercise, but should also be aware of how long that they are spending on their feet. Taking appropriate breaks with the feet up should be seen as part of the compensation package for being pregnant. Because pregnancy is often a joyous occasion, it is important to make sure to take precautions so it can be so a majority of the time.
People who are overweight can reduce their chances of getting varicose veins, along with a whole host of other diseases related to obesity including heart disease, stroke and diabetes, by losing weight. While that is easier said than done, it is important that the person start on the journey to being healthier and less prone to disease. By consulting with a physician about exercise and a nutritionist about food, it is possible that the person can become leaner. It will generally take small steps, persistence and a permanent change in both eating and exercise habits, but the payoff will be worth it in the end.
People who have varicose veins can expect to have to deal with them over the long term. Treatment of the symptoms may include getting off of one’s feet and elevating them and wearing compression hosiery. By getting off of the feet, someone who has varicose veins will be using gravity to help move the blood that has pooled out of the legs and back to the heart. This can help reduce swelling and pain.
Compression hosiery helps lower the amount of blood pooling in the legs. By applying more pressure at the ankles and less at the top of the sock, the compression sock encourages and supports the veins in their work to defy gravity and get the blood to the heart. This allows the blood to circulate better and to keep the legs from getting blood clots which can be dangerous to both life and limb. The best part is that compression socks are now stylish not just in look but also in use. They do come in several styles and the fabrics mimic the look of normal socks. Compression socks are also utilized by some athletes to improve performance on the field.
CARDIAC BLOOD POOL SCAN
A cardiac blood pool scan shows how well your heart is pumping blood to the rest of your body. During this test, a small amount of a radioactive substance called a tracer is injected into a vein. A gamma camera detects the radioactive material as it flows through the heart and lungs.
The percentage of blood pumped out of the heart with each heartbeat is called the ejection fraction. It provides an estimate of how well the heart is working.
THERE ARE TWO TYPES OF CARDIAC BLOOD POOL SCANS.
- First-pass scan. This scan makes pictures of the blood as it goes through the heart and lungs the first time. A first-pass scan can be used in children to look for heart problems that have been present since birth (congenital heart disease).
- Gated scan or multigated acquisition (MUGA) scan. This scan uses the electrical signals of the heart to trigger the camera to take a series of pictures that can be viewed later like a motion picture. The pictures record the heart’s motion and determine if it is pumping (contracting) properly. MUGA scanning may take 2 to 3 hours to obtain all the needed views and can be done both before and after you exercise. You may be given nitroglycerin to see how your heart responds to this medicine. MUGA scanning may be done after a first-pass scan. It is usually not done on children.
WHY IT IS DONE
A cardiac blood pool scan is done to:
- Check the size of the heart chambers (ventricles).
- Check the pumping action of the lower ventricles.
- Look for an abnormality in the wall of the ventricles, such as an aneurysm.
- Look for abnormal movement of blood between the heart chambers.
HOW TO PREPARE
Before having a cardiac blood pool scan, tell your health professional if you:
- Are allergic to any medicines.
- Are or might be pregnant.
- Have recently had any test that uses a radioactive tracer, such as a bone scan or thyroid scan.
- Have a pacemaker or other metal device implanted in your chest. These devices may make it hard to obtain clear pictures of the blood flow through the heart.
You may be asked not to eat or drink for a few hours before the test. You should not have any caffeine or smoke for 4 to 6 hours before the test.
If testing will include exercise, you should wear comfortable shoes and clothing.
Many medicines may affect the results of this test. Be sure to tell your health professional about all the nonprescription and prescription medicines you take.
Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information.
HOW IT IS DONE
A cardiac blood pool scan usually is done in a hospital by a radiology or nuclear medicine technician. Most people do not have to stay overnight in the hospital.
BEFORE THE TEST
You will need to remove any jewelry that might interfere with the scan. You may need to take off all or most of your clothes. You will be given a cloth or paper gown to use during the test.
DURING THE TEST
You will lie on an examination table beneath the gamma camera. Electrocardiogram (EKG, ECG) electrodes are attached to your chest so that the electrical signal of your heart can also be detected. Then the camera, which is a round metal instrument about 3 ft (1 m) wide, will be positioned close to your body. If you are cold or uncomfortable lying on the table, ask the technician for a pillow or blanket. The camera may be positioned in different places across your chest to record different views of your heart.
The technician cleans the site on your arm where the radioactive tracer will be injected. An elastic band, or tourniquet, is then wrapped around your upper arm to temporarily stop the flow of blood through the veins in your arm. This makes it easier to put the needle into a vein properly. A small amount of the radioactive tracer is then injected, usually into a vein on the inside of your elbow.
If you are having a multigated acquisition (MUGA) scan, a blood sample may be taken and the tracer added to it, and then it will be reinjected into your vein.
The gamma camera will take pictures as the radioactive tracer moves through your bloodstream and into your heart. It is important not to move while the scan is under way.
The camera does not produce any radiation, so you are not exposed to any additional radiation while the scan is being done. You will need to hold still during each view, which may take up to 5 minutes. You may be asked to:
- Change position for each different view.
- Do some exercise between scans to see how well your heart functions after the stress of exercise.
- Take nitroglycerin to see how well your heart responds to the medicine.
The radioactive tracer is designed to attach to your blood cells, which takes 20 to 30 minutes. You will then have to wait 2 to 4 hours until the tracer is completely absorbed by your red blood cells. During that time, you may have to stay at the test center. Some test centers may allow you to leave and come back when it is time for your scan.
Testing usually takes 10 minutes to an hour, depending on which studies are done. MUGA scanning may require 2 to 3 hours to obtain all the needed views.
AFTER THE TEST
Once your scan is complete, you usually will be able to leave the testing room right away. You may have to wait at the test center until all of your scan images have been reviewed. If you moved during the scan and the images turned out blurry, the scan may have to be repeated.
Drink lots of water and urinate frequently after your scan to make sure that the tracer flushes completely out of your body. It takes a day or two for the tracer to be completely eliminated.