Encyclopedia of Ayurvedic Medicinal Plants

Korotkoff’s sounds 

         Korotkoff’s sounds: During inflation of the cuff, when the air pressure in the cuff exceeds the arterial pressure, the brachial artery gets completely occluded. During deflation, when the cuff pressure fails just below the systolic pressure, the jetting of blood during the peak of systole produces the sudden sharp, tapping sound. As deflation proceeds occlusion of the artery gets progressively reduced and the resulting turbulence makes the sound louder. Further lowering of cuff pressure reduce the turbulence causing muffling of the sound. Finally when the cuff pressure goes below the diastolic pressure, the occlusion is completely relieved and flow becomes streamline so the sounds disappear completely.

        Ausculatory gap: Occasionally when the blood pressure is determined byauscultatory method, the Korotkoff’s sound appear first, then disappear completely to reappear after a gap. This gap is called auscultatory gap or silent gap. This phenomenon is seen in certain patients with hypertension. This leads to errors in systolic pressure recordings, as the reapperance of the sound may be taken as the systolic blood pressure. To avoid this, the blood pressure is determined by PALPATORY method first, to get an approximate idea about systolic pressure and then by auscultatory method.

Factors maintaining blood pressure:

1. Pumping action of heart

2. Blood volume

3. Peripheral resistance

4. Elasticity of the vessel wall

5. Viscosity of blood.

Variations in blood pressure:

A. Physiological:

1. Age: Blood pressure increases with age

2. Sex: In women, blood pressure is lower than in men till menopause. After menopause, it is slightly higher than in men.

3. Build: Obese people tend to have higher blood pressure.

4. Sleep: During sleep, a fall is seen, especially in the first 1 to 2 hours.

5. Emotional excitement: There is an increase especially in the systolic pressure.

6. Diurnal variation: Maximum towards the evening and minimum in the morning.

7. Posture: Slight variations can occurwith change in posture. On suddenly standing up from recumbent posture there is a fall in systolic pressure due to the effect of gravity. Venous pooling occurs in the dependent parts. Venous return decreases and this in turn causes reduction in cardiac output. This fall in pressure stimulates the baroreceptor mechanism resulting in a compensatory rise in pressure, mainly the diastolic pressure.

8. Exercise: In all types of exercise there is a marked rise in systolic pressure. This is due to many factors.

a. Sym pathetic discharge: The generalised sym pathetic discharge which occurs during exercise, causes stimulation of vasomotor centre, which leads to increase in heart rate and force of contraction which results in an increase in cardiac output. The increase in circulating catecholamines also results in an increase in cardiac output. Sympathetic venoconstriction increases venous return and hence cardiac output increase.

b. Skelital muscle pump.

c. Respiratory pump.

But the changes in diastolic pressure depend on the nature of exercise. Whole body dynamic exercises such as running, brisk walking, jogging etc. cause vasodilatation in all the muscles, hence a decrease in peripheral resistance and fall in diastolic pressure.

Exercises involving a single group of muscles eg: using muscles of one upper limb alone will cause vasodi latation in that particular group of muscles and compensatory vasoconstriction in all other groups of muscles. Hence an increases in peripheral resistance and a rise in diastolic pressure occur.