Blood Pressure Measurement

Blood Pressure Measurement is the most commonly performed test during medical examination. The main factors that control blood pressure are the force of the heartbeat. the width and flexibility of the arteries, the volume of blood in the circulation, and the viscosity of the blood. Sudden or chronic changes from normal in any of these factors can lead to abnormally high or low blood pressure.

High blood pressure (hypertension) is a major factor associated with increased risk of heart attack, heart failure and stroke. Because there are rarely any symptoms until the blood pressure is dangerously high, routine blood pressure checks allow increases to be detected early so that treatment can reduce the risks.

Blood pressure is recorded at regular intervals during surgery and general anaesthesia, and during intensive care monitoring after severe injury or in serious illness. Blood pressure that drops far below normal, especially when the fall is rapid, indicates shock or heart failure

Blood pressure is measured by an instrument called a sphygmomanometer, which records the height in millimetres of a column of mercury that the force of the blood pressure can support. An inflatable cuff attached to the sphygmomanometer is wrapped securely around the patient's upper arm and the examiner places a stethoscope over the large artery in the bend of the elbow. The cuff is inflated until the pressure it exerts is sufficient to stop circulation through the artery. Pressure in the cuff is slowly released until a thumping pulse is heard through the stethoscope.

The height of the mercury column at the first thump indicates the systolic blood pressure - the pressure transmitted to the artery when the heart contracts. As cuff pressure is further reduced, the pulsing thumps become softer. The height of mercury when the last pulse is heard indicates diastolic blood pressure - the pressure in the artery when the heart is relaxed. The diastolic reading is the more significant indication of whether blood pressure is abnormally high.

Although blood pressure is generally taken in upper arm arteries, it may be measured in the thighs when there are disturbances of circulation to the lower limbs, and in the chambers of the heart during CARDIACCATHETERISATION.

A muscle biopsy is rarely indicated before completing such an evaluation and determining a preliminary diagnosis. During the biopsy, there is usually minimal or no discomfort. You may feel some pressure or "tugging" sensations. The most commonly biopsied muscles are the biceps muscle in the arm and the quadriceps muscle in the leg. Other muscles such as the deltoid and the calf muscles can also be biopsied if indicated. It is equally important to inform the patient that a muscle biopsy, like all other biopsies, is subject to sampling error and a negative biopsy does not exclude the presence of a suspected disease. A muscle biopsy may be also be done to tell the difference between nerve and muscle disorders. If the biopsy has to be done by a surgeon unfamiliar with such matters, it is very important that the surgeon communicates with the neuromuscular specialist or the treating neurologist before the biopsy.

Why the test is performed?

A muscle biopsy may be performed for many reasons, including the following:

• To identify metabolic defects of the muscle.
• To detect Infections that affect the muscles (such as trichinosis or toxoplasmosis ).
• To identify specific muscular disorders such as muscular dystrophy or congenital myopathy.
• To distinguish between neurogenic and myopathic disorders.

How the test will feel?

• During the biopsy, there is usually minimal or no discomfort. You may feel some pressure or "tugging" sensations.
• The anesthetic may burn or sting when injected (before the area becomes numb).
• After the anesthetic wears off, the area may be sore for about a week.

What the risks are?

The risks are small, but may include:

• Bleeding of the site.
• Damage to the muscle tissue or other tissues in the area.
• Infection (a slight risk any time the skin is broken).

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