Medical Questions & Answers » Blood Presuure

How Blood Test Done?

medicalquestions — Thu, 05 Mar 2009 06:00:11 +0000

My doctor wants me to have a blood test, but I am scared stiff. What actually happens during a blood test? Does it hurt?
The doctor may take the blood in the surgery or you may be asked to go to a nearby pathology clinic. Either way, the sample will be sent to a laboratory for analysis, unless a relatively simple test is required, in which case the doctor may have the necessary equipment in the surgery to perform the analysis (eg. for blood sugar).
Blood is extracted by inserting a hollow needle into a vein and allowing an amount of blood to flow into an attached tube. The blood will usually be taken from a vein at the bend in your elbow, but if that is not sufficiently prominent, the nurse may try your forearm or the back of your hand. It takes only a minute or so. Once the nurse has sufficient blood for the tests that have been ordered, the needle will be withdrawn and a dressing or cotton wool pressed on to the point of entry to stop the flow. You will need to leave it in place for half an hour or so until the blood clots naturally.
Sometimes the blood can be taken at any time of the day, but if the test is to measure your metabolism (how your body converts food into energy), the test must be performed in the early morning after a 12 hour fast, or at particular times after you have eaten a certain measured amount of food.
Blood tests to measure the amount of certain drugs in the system are also taken at specific times after the tablets are swallowed.
Blood tests hurt far less than a normal injection such as a flu shot because nothing is injected. If you do not watch the nurse, you will barely notice the discomfort, which will be no worse than having someone pinch your skin.

I had a blood test at a local shopping centre that showed my urea to be 10.9 instead of between 2.5 and 7.9. What does this mean?
Random blood tests at shopping centres are notoriously unreliable, particularly for substances such as cholesterol. I assume that in your case, the high urea reading was an isolated finding on a machine that scans for many different substances.
A urea reading of 10.9 is certainly high, and the first thing you should do is to arrange for your GP to repeat the test using a recognised laboratory. This reading can then be compared to other results, the results of a physical examination, and your medical history, to make an appropriate diagnosis.
Elevated urea levels are usually found in kidney disease, but other tests are usually abnormal as well.
Don’t start worrying until you confirm that there really is a problem.

Under Control Hemoglobin

medicalquestions — Sun, 11 Jan 2009 06:55:02 +0000

My diabetes is under control but the hemoglobin level is 17.9g%. The doctor says it should not exceed 15g% and wants to remove some of my blood. That sounds dire! What could be the cause and what are the treatments available to lower hemoglobin?
You may be suffering from a condition called Polycythemia Vera where the hemoglobin values tend to go higher than 18g%. When hemoglobin levels are high the blood tends to be thicker, and can cause clotting in critically narrowed arteries, a typical side effect of diabetes. The simplest treatment for polycythemia Vera is blood donation every now and again (about once in 3-6 months), depending on the level of hemoglobin. However, you would do well to see a hematologist to confirm this diagnosis.

Check Out Your Pressure

medicalquestions — Wed, 24 Dec 2008 12:48:07 +0000

I’m suffering from congenital ventricular septal defect and severe pulmonary hypertension with Eisenmenger complex. Now I have polycythemia as well. How does Viagra help in pulmonary hypertension?
Your problem is a birth defect which probably started off as a ventricular septal defect, which has progressed to a situation where the pressures on the right side of your heart are higher than that on the left side. Normally the right side pressures or PA pressure would be less than 25 mmHg. The echocardiograph findings as detailed by you would indicate a reversal of pressures which, in medical parlance, is termed Eisenmengerisation. If the echo diagnosis is accurate, surgical correction would be very risky and not advisable. Sildenfil(Viagra) functions as a phosphodieaterase inhibitor, relaxing the lining of the arterioles and has been used in cases of Pulmonary Hypertension with benefits documented. This drug has recently been approved in the US for treating PH. However it has to be prescribed by your cardiologist and started in extremely small doses. The polycythemia or increased Hemoglobin, is the body’s response to less oxygen supply due to the admixture of pure and impure blood in a condition like yours. Any treatment options can only be made after a clinical examination.
Heart lung transplants are not done on a routine basis in India due to certain practical problems. The best centers are abroad but most of them are hesitant in accepting overseas patients due to the long waiting list of local patients.

Are sleeping pills harmful?

medicalquestions — Mon, 11 Aug 2008 06:00:27 +0000

Question: Are sleeping pills harmful?
Most sleeping pills are very safe, provided they are taken in the recommended manner, but if used constantly for many weeks or months, patients may find it very difficult to stop them as they become dependent upon them. The greatest problem with the use of sleeping pills is that they are taken unnecessarily, particularly by elderly people who do not need large amounts of sleep. These pills are better taken intermittently when really needed, and they will work far more effectively.

Question: As a 77 year old, my doctor has suggested that I take 100 mg of aspirin every day to reduce my risk of having a stroke or heart attack, but I have had a stomach ulcer in the past and take Zantac every day. I was told that I should never take aspirin again because of my ulcer. What should I do?
Aspirin is a marvelous medication, and one of the oldest in current medical use, having being first marketed by a German chemist (Bayer) in 1899. It may be used to relieve pain, reduce inflammation (eg. in arthritic joints), decrease the risk of bowel cancer and reduce the ability of blood to clot.
This last use makes it suitable to reduce the risk of blood clots in the brain (stroke) or coronary arteries (heart attack), and as a result it is widely recommended by doctors to be taken regularly by all patients over 50. When used to relieve pain, aspirin is taken in doses of 600 mg (two tablets), four times a day, but when used to reduce blood clotting, only a very small dose of 75 to 100 mg a day is necessary, and strangely, higher doses may be less effective in reducing the risk of clots.
Aspirin also has side effects, most commonly resulting in stomach pain, and sometimes bleeding from the stomach, but this effect is dose dependent, and the higher the dose, the greater the risk of side effects. Low-dose aspirin is available in special formulations that reduce, but do not entirely eliminate, the risk of stomach side effects. These are marketed as Astrix, Cartia and Cardiprin, and are subsidised by the government for pensioners under the pharmaceutical benefits scheme.
It is possible that you will suffer stomach side effects from taking low dose aspirin long term, and if this occurs there is a substitute medication (Plavix), that is much more expensive than aspirin, but it does not have some of the added benefits of aspirin (eg. against bowel cancer). It is only subsidized by the government under very stringent conditions.

Drugs for High Blood Pressure

medicalquestions — Mon, 11 Aug 2008 06:00:06 +0000

Question: Eight years ago, a blood test showed an excess of uric acid, and although I had no problems with gout or arthritis, my doctor put me on Zyloprim each day, saying failure to take the tablet could result in gout. A health shop proprietor said Zyloprim could actually cause problems if taken long term. Can you advise me?
High levels of uric acid in the blood stream can cause recurrent attacks of gout. Because of the severe pain associated with gout, these attacks are very obvious to the sufferer. Uric acid has another more sinister effect on the kidneys. These can be slowly damaged, and unless kidney stones form, the presence of excessive levels of uric acid may not show up until the kidney starts to fail, and the patient presents with a totally different set of symptoms.
Zyloprim (also known as Progout and allopurinol) is a drug that lowers the amount of uric acid in the blood stream. It has been available for over 40 years, so a great deal is known about its side effects and complications. A very small number of patients do have long-term problems with its use, but the risks of using Zyloprim are far less than the risks of high uric acid levels.
Regular blood tests should be performed every year while you are taking the medication to check the level of uric acid, and the liver and kidney function. Some patients require only a low dose of Zyloprim to reduce their uric acid levels, and this can be judged by the blood test results. The drug is available in both 100 and 300 milligram sizes, so reduction of dosage in those patients who can be controlled more readily can be easily achieved. Follow the advice of your doctor rather than a ‘health’ shop proprietor, whose advice may be biased by a desire to sell you his products.

Question: Can you tell me about a drug called Capoten that my doctor has prescribed for me?
Capoten (also known as captopril) is a quite modern drug that is widely and successfully used to treat high blood pressure and heart failure. Its only absolute contraindication is pregnancy, but it should be used with caution in patients with poor kidney function, and care must be used if the patient has a general anaesthetic.
It has few side effects, the most common ones a being a cough and lightheadedness because the blood pressure has dropped too far. Anyone on treatment with blood pressure medication should be checked regularly by a doctor, and provided no problems are found, this medication can be used confidently for many years.

Low blood pressure

medicalquestions — Fri, 18 Apr 2008 06:00:49 +0000

Question: You constantly hear about high blood pressure, but what about low blood pressure. What causes this?
The level of blood pressure is due to a combination of the amount of blood present in the circulation, the force of contraction of the heart and the diameter of the blood vessels.
If you lose a large amount of blood your blood pressure will drop due to a lack of blood. If your heart contracts forcibly your blood pressure may rise excessively, but if it beats weakly it may fall. If the arteries become dilated, as may happen with frights, sudden change in Position or shock, the blood pressure may fall. If they are narrowed by hardening from excess cholesterol, or by spasm from chemical stimuli within the body, the blood pressure will rise.
The regulation of blood pressure is very complex, and numerous chemical and physical factors are involved. People with persistently low blood pressure need investigations to find out why it is low, but in many cases no apparent cause can be found. In the elderly, narrowing of arteries may restrict the blood supply to the brain, and even though their blood pressure is normal, they may feel light headed and dizzy when rising from a bed or chair.

Low blood sugar

medicalquestions — Fri, 18 Apr 2008 06:00:17 +0000

Question: Could you please explain what causes low blood sugar, the symptoms and the treatment?
Low blood sugar (hypoglycemia) is caused by an inadequate intake of carbohydrate foods (ie. starvation), excess use of drugs used to treat diabetes, alcoholism and by a very rare tumour that secretes excess insulin.
Sugars are the fuel of the body, and ate chemically ‘burned’ to provide the energy necessary for us to function. There are many different types of sugar in our diet, including sucrose (the white stuff we sprinkle on our cereal), glucose, fructose (fruit sugar) and lactose (milk sugar).
Starvation is rare in Australia, and so there are very few people who suffer from true hypoglycemia. There are people who lead a very active lifestyle who burn up their body sugar rapidly, and who therefore feel much better shortly after taking sugar containing foods. Rest usually gives the same result, but mote slowly, as reserves of sugars are released by the liver into the bloodstream. This problem is far more common in women than men.
The symptoms of a transient episode of low blood sugar are tiredness, burred and double vision, headache, light headedness and personality changes.
True, prolonged hypoglycemia is very rare, and I have never encountered a patient with this problem in 25 years of general practice. Temporary symptoms of hypoglycemia after exercise or stress are common, and are not a reason for concern. If you feel that you suffer from this problem regularly, suck some barley sugar before exercise or at times of stress.

Worrying about Blood Pressure

medicalquestions — Thu, 17 Apr 2008 06:00:48 +0000

Question: Why do doctors keep worrying about my blood pressure. Is it really that important to keep it low?
Ariy plumber will tell you that if a pipe carries water at a pressure higher than the pressure it was designed for, it will eventually rupture. If the pressure in the pipe is not only to high but varies rapidly in its level, the rupture will occur even sooner because of the excessive stresses on the pipe.
Exactly the same situation occurs in the human body when the pressure of blood in the arteries becomes too high. The arteries of a person with high blood pressure will become hardened, brittle and eventually rupture, causing a stroke, heart attack or other serious injury to vital organs.
The majority of people with high blood pressure have no symptoms of the problem for many years, and by that time it may be too late. Once diagnosed, tests will be done to see if there is any specific cause for the increased blood pressure, but the majority of people have ‘essential’ hypertension, for which there is no single identifiable cause. Treatment is necessary in all cases of hypertension to prevent the serious long-term problems that may occur.
There is no cure for high blood pressure, but it can be very successfully controlled in the majority of patients by taking one or two tablets a day.

Treatment for high blood pressure

medicalquestions — Thu, 17 Apr 2008 06:00:29 +0000

Question: I am a very fit, healthy and normal weight 32 year old, but my doctor wants to start me on treatment for high blood pressure. Why?
Unfortunately, hypertension (high blood pressure) does not always respect youth or fitness, although these factors certainly help. 80% of people with hypertension have no specific cause for the condition, although it does tend to run in families. If a high level of blood pressure is found on several occasions, tests will be done to exclude any specific cause, and if none can be found, it is necessary to start treatment to control the pressure level of the blood.
This treatment must be continued for many years, as it does not cure the condition, but controls it only while the medication is taken. It is important to control the blood pressure adequately, despite the fact that you may have no symptoms now, because a high level for many years will greatly increase your risk of strokes and heart attacks. The only things that you can do to help the situation are keep your weight at a reasonable level, avoid salt and stop smoking.

Correct figure for Blood Pressure

medicalquestions — Thu, 17 Apr 2008 06:00:27 +0000

Question: What is the correct figure for blood pressure? Mine is 140/90 and my doctor keeps checking it every time I see him. He says it is alright, but this constant checking worries me.
The actual values for blood pressure vary with many things such as exercise, anxiety, age, fitness, smoking and drinking habits, weight and medications. This is why doctors never give absolute values for what is normal and abnormal in blood pressure values.
It is a good idea to have your doctor check the pressure at regular intervals, particularly if you are over 40. Your general practitioner is a good and careful one. It is very easy to forget that a patient might have a blood pressure problem, and not take it regularly. Your blood pressure is bordering on being too high, and that is why he is checking it every visit.
There are two figures quoted when blood pressure is measured. When the heart contracts, blood is moved around the body under high (or systolic) pressure. When the heart relaxes between beats, the blood continues to flow due to the lower (or diastolic) pressure exerted by the elasticity of the artery walls. In your case, your systolic pressure is 140, and diastolic 90.
When one, or both, of these pressures exceeds a safe level, the person is said to suffer from high blood pressure or hypertension. It is more dangerous to have the diastolic pressure high, as the systolic pressure can vary considerably due to exercise or stress. You can help prevent and treat hypertension by keeping your weight within reasonable limits, not eating excessive amounts of salt, not smoking and exercising.