What Is Blood Pressure?

Blood pressure (BP) refers to the lateral pressure that acts on the wall of a unit area of blood when blood flows in a blood vessel, and it is the driving force that pushes blood to flow in a blood vessel. It is called arterial blood pressure, capillary blood pressure and venous blood pressure in different blood vessels. Generally speaking, the blood pressure refers to the arterial blood pressure of the systemic circulation.

Basic Information

Chinese name

blood pressure

Foreign name

blood pressure, BP

Influencing factors

Stroke output, peripheral resistance, heart rate, etc.

hypertension

Systolic blood pressure 140mmHg Diastolic blood pressure 90mmHg

Hypotension

Blood pressure below 90 / 60mmHg

Factors affecting blood pressure

There are five main factors affecting arterial blood pressure: stroke volume; peripheral resistance; heart rate; elasticity of the aorta and aortic wall; circulating blood volume and blood vessel volume.

Blood pressure measurement

Blood pressure measurement methods include direct measurement and indirect measurement: Direct measurement is a long catheter dissolved with anticoagulant, which is sent to the aorta by percutaneous puncture. The catheter is connected to a pressure sensor to directly display blood pressure. This law is invasive and only applies to certain special circumstances. The indirect measurement method is the cuff compression method, which is measured with a sphygmomanometer. Sphygmomanometers are mercury, spring and electronic. The indirect measurement method is simple and easy to implement and is currently widely used in clinical practice.
1. Measurement method (cuff compression method)
(1) The brachial artery is at the same level as the heart. Flatten the mid-axillary line in the supine position and the fourth rib in the sitting position.
(2) Roll up your sleeves to expose your arms, straighten your elbows, and palms up.
(3) Turn on the sphygmomanometer, stabilize it vertically, and turn on the mercury tank switch.
(4) Remove the air in the cuff, wrap the cuff in the middle of the upper arm, and the lower edge is 2 to 3 cm away from the elbow socket.
(5) Touch the brachial artery pulsation, place the head of the stethoscope on the obvious pulsation, fix it by hand, press gently, close the valve, inflate until the brachial artery pulsation disappears, and then increase 20-30mmHg.
(6) Slowly deflate, it is advisable to lower the mercury column by 4mmHg / sec. Pay attention to changes in the mercury column scale and brachial artery sound.
(7) The scale indicated by the mercury column when the first pulsating sound appears in the stethoscope is the systolic pressure, and the scale indicated by the mercury column when the pulsating sound suddenly weakens or disappears is the diastolic pressure.
(8) After the measurement is completed, exhaust the cuffs, tighten the screw cap on the valve, unfasten the cuffs, put them into the box after finishing, and turn off the mercury tank switch.
(9) Record the measured value, and record using fractional formula, namely systolic / diastolic blood pressure.
2. Notes (1) The sphygmomanometer should be regularly tested and proofread to maintain accuracy.
(2) For those who need to closely monitor blood pressure, "four fixed" should be achieved, that is, fixed time, fixed location, fixed position, fixed blood pressure monitor.
(3) There are no factors that affect blood pressure such as strenuous exercise, smoking, and emotional changes within the first 30 minutes of measurement. The mood is stable and the cuffs should not be too tight.
(4) Select the appropriate cuff as required.
(5) Do not inflate too fast or too fast to prevent mercury from overflowing; do not deflate too fast or too slow to avoid reading errors.
(6) If the blood pressure is unclear or abnormal, it should be re-measured. When retesting, wait until the mercury column drops to the "0" point before measuring.
(7) Measured on the arm of the hemiplegia patient.

Blood pressure assessment

1. Normal blood pressure The normal blood pressure range is relatively stable in normal adults. The normal range of systolic blood pressure is 90-139mmHg, diastolic blood pressure is 60-89mmHg, and pulse pressure is 30-40mmHg.
2. Abnormal blood pressure (1) Hypertension: without the use of antihypertensive drugs, systolic blood pressure 140mmHg and / or diastolic blood pressure 90mmHg in adults over 18 years of age.
(2) Hypotension: blood pressure is lower than 90 / 60mmHg.

Clinical significance of blood pressure

1. Blood pressure can judge cardiac function and peripheral vascular resistance.
2. Blood pressure is also an important content for diagnosing diseases, observing changes in conditions, and judging the effect of treatment.