Blood pressure is measured using a sphygmomanometer. An inflatable ‘cuff’ is placed around the upper arm and air pumped into it until a level of 250mm/Hg is reached, as seen on the dial. This pressure occludes the underlying arteries. The practitioner places the end of the stethoscope over the front of the elbow and listens. Nothing should be heard. This blood hits the wall of the artery with a
The air is slowly released from the cuff and as thump, which can be heard through the stetho- the pressure drops there comes a point when the scope. As the cuff pressure continues to drop and strength of the heartbeat overrides the pressure in less impedance ensues, the blood flow becomes the cuff and blood is squirted down the arteries, smooth and the thumping stops. Cardiologists teach us that there are five sound stages, ranging from stage I – the initial thump – to stage V – a return to silence.
Simple and 24-hour blood pressure machines Sensitive computers are now being used to take blood pressure and can be bought at any medical outlet. These generally comprise a finger-sized cuff that slips over a digit and measures the underlying pressure in the arteries. These are fairly accurate and can be used to check an individual’s blood pressure at different times throughout the day.
Twenty-four-hour blood pressure measurements are of benefit in diagnosis if sporadic symptoms such as dizziness or blackouts are associated with blood pressure. A small computer is carried for 24 hours with leads attached to the body to measure blood pressure. A patient records the time of any symptoms and this is compared, by computer, with the blood pressure measurements. It is worth noting that many individuals who may have high blood pressure when visiting the doctor’s surgery or at times of stress may spend much of their time with normal blood pressure and incorrectly be prescribed treatment. Many hypertensives have normal blood pressure during the night, which suggests to a holistic physician that the stress of consciousness is the underlying cause and that a relaxation or meditation programme may be of benefit rather than drugs.
C J Doppler was an Austrian physicist who noticed that sound waves change if bounced off something that is moving. This is a very simplified description of what is known as the Doppler principle. A Doppler machine passes out a sound wave that bounces off moving blood within a vessel and can show the speed of flow. As this is very dependent upon the patency of the vessel, this technique can be used as a non-invasive investigation to check for arteriosclerosis or occlusion within arteries.
An ECG is the measurement of electrical conductivity in the heart muscle. For an explanation of the origin, initiation and travel of these electric impulses, see Heart, irregular beats.
An ECG is a non-invasive technique that can be of great benefit in diagnosing heart diseases. There is no reason to avoid such an examination although results need to be correlated with symptoms, as with all investigations.
An ECG produced while somebody is on a treadmill is known as a stress ECG and shows the electrical conductivity when the heart has an increased need for oxygen. This test can be very useful in demonstrating cardiac muscle disease because any injury from, say, a heart attack will damage some of the heart muscle and prevent conduction through that part.
Electrodes are placed around the heart and on both wrists and ankles because the electrical impulse will be picked up even at distances. The computer within an ECG will correlate all the information from all the leads and print out a pattern that requires a certain amount of expertise to interpret.
The Holter monitor is a small box that attaches to the side of an individual and is connected to leads that are placed on the chest. The monitor will record the heart rate and electrical pattern over a 24-hour period. The individual notes down any periods of cardiac symptoms, such as chest pain or tachycardia, and any associated heart irregularity can be ascertained.
Electroencephalogram The brain conducts its function through the transmission of chemicals from one nerve to another. This process releases electricity, which can be measured by placing electrodes around the scalp. An EEG can demonstrate not only function but also structural changes or damage within the brain. Very useful in conditions such as epilepsy or in diagnosing tumours, the EEG is a safe and effective method of diagnosis.
Magnetic resonance imaging Over the last decade a technique of visualizing internal organs and structures has been developed using magnets rather than sound or X-ray. The technique is complex, and computer imaging from the information sent by powerful magnets, which surround the body part to be investigated, is required.
The MRI has its critics, suggesting that the imaging is not all that accurate in certain areas of the body and it is often necessary to use ‘dyes’ which are magnetic substances that may cause problems that we have yet to understand. These dyes are, however, far safer than the known damage created by the CT scan dyes containing iodine .
Magnetic resonance imaging usually involves the patient being passed into a body-sized tube and being asked to keep absolutely still. Whilst claustrophobic, the technique is not in any way invasive or painful but may take up to an hour to complete a full body scan. These MRI scans are extremely sensitive and can be used in place of CT scans in many if not most investigations.
Magnetic resonance imaging may impart cerr tain dangers as we now begin to see that magnetic energy may disrupt electromagnetic function in the body but at the moment it is safer than X-rays. If confronted with a need for hi-tech investigation, always ask whether MRI would be available and as accurate.
Radiography is the most common, and potentially most damaging, of modern medicine’s investigations.
X-rays are very high frequency waves that pass through most compounds. A radiogram is basically a photograph created by X-rays hitting a wave-sensitive plate. As X-rays are passed through the body, the denser the tissue the more X-rays are absorbed. The less dense tissue allows more X-rays to pass through, which hit the plate and show up as a white/grey area. Bones, being dense, are seen as white on an X-ray because no X-rays hit the plate, whereas air space in the lungs is seen as black because all the X-rays hit the plate. X-rays are harmful, there is no debate over that whatsoever. The argument concerns whether the amount we receive through an investigation is harmful or not .
Angiography is a frequently used X-ray technique. A radio-opaque dye is injected into the bloodstream and X-rays are taken of the arteries that are suspected of being diseased or narrowed. This technique is popular but has its critics. Some rarely-repeated studies have shown that angiography is open to misinterpretation or actually imparts false information. Unnecessary operations are therefore conducted. This, combined with the potential risk of an X-ray, should make angiography a last-choice investigation rather than a first choice, but overall is likely to be of benefit in the right case.
Myelography is an X-ray technique used on the spinal column that also uses radio-opaque dyes. When injected into the spinal column to show disc lesions, a percentage may cause inflammation leading to persistent pain and problems with movement. The dyes themselves may be toxic to the kidneys and may have a direct effect on the nervous system, leading to paralysis. Dyes used for CT scans contain iodine, which is known to be toxic to the thyroid gland if taken in excess. The trouble is, everyone is different and nobody is certain how much is too much for any individual patient. Try other techniques of imaging before allowing dyes to be used.
Bone density scanning is becoming popular and whilst it carries a low risk of X-ray exposure the scan itself is not a particularly reliable investigation. A variety of studies have suggested that the accuracy is questionable and that bone density can change, depending upon such factors as movement and recent diet, so that general or yearly screening is not reliable. One study followed up a group of a 1,000 women who were considered to be at high risk of osteoporosis via a scan, only to find that they had fewer hip fractures than the control group. Neither group were given any orthodox treatment.
There are other alternatives for measuring bone density and, in principle, these other ultrasound techniques can be done with safety.
Computed axial tomography Computed axial tomography scans are formed by passing an X-ray image through a computer that is highly sensitive and therefore produces much more detailed pictures. These scans use a three-dimensional picture, thereby giving the physician an idea of the depth and size of a tumour with far more accuracy than a two-dimensional X-ray film.
A CT scan provides an enormous amount of radiation, especially if the procedure is repeated because of movement of the patient, error within the computer system or because the technique is being used to monitor a changing situation.
Whilst extremely accurate, many of the results can be obtained through magnetic resonance imaging but with lower risks. Also, CT scans are often used despite the fact that whatever the results, no change in treatment is likely. It simply gives a prognosis.
Ultrasound or sonography has been developed over the last 30 years within the medical fraternity. The principle has been around a lot longer and was used by geographers to chart the depth of oceans. The principle is simple. A sound wave is emitted from a transmitter into tissues and rebounds back to a receptor lying next to the transmitter. A less dense tissue will reflect less sound waves, whereas a solid object will bounce back all of the waves. This information is transformed into a visual picture by a computer, much like a radio will pick up inaudible radio waves and transform them into sound through mechanical means.
One trial has shown that using ultrasound eleven times in a pregnancy may produce babies that are small for their age, but otherwise no other detrimental effect has been demonstrated. I suspect that because the foetus is a highly sensitive state of being, the ultrasound is disturbing and creates a stress response rather than having any direct detrimental effect upon tissue growth.
Ultrasound can be used for most diagnoses except for organs such as the brain, which is encased in a solid shell, or organs that are too deep in the body to be imaged without other organs being in the way. Basically, problems may be imaged and a diagnosis made on any part from the neck down with the use of ultrasound. Bone density can be measured without X-rays using this method.
Ultrasound machines vary in size but the actual transmitter/receptor is rarely larger than a mobile telephone and is placed over the area to be investigated. A sound-transmitting gel is applied to allow a freer movement and less interference from the skin surface. Ultra-sound diagnosis rarely takes more than a few minutes in the hands of a skilled technician and reports can be read immediately.