Blood Pressure PDF

## Blood Pressure - Pressure of blood in the arteries as a result of heart output and vascular resistance. - Contains systolic pressure (pressure in arteries when heart contracts) and diastolic pressure (when heart relaxes). - Measured in mmHg. - **Pulse pressure:** PP = SP - DP. ### Normal Blood...

## Blood Pressure - Pressure of blood in the arteries as a result of heart output and vascular resistance. - Contains systolic pressure (pressure in arteries when heart contracts) and diastolic pressure (when heart relaxes). - Measured in mmHg. - **Pulse pressure:** PP = SP - DP. ### Normal Blood Pressure Values | Category | Blood Pressure (mmHg) | |---|---| | Normotension (normal blood pressure) | 120/80 | | Hypertension | > 140/90 | | Hypotension | < 100/60 | | Optimal BP | < 120/80 | | Normal BP | 120-129/80-84 | | Normal High BP | 130-139/85-89 | ### Factors Affecting Blood Pressure - **Age:** - Children have low BP (80/60 at birth) which increases until 18. - Older adults have higher BP due to decreased wall elasticity, rigid arteries. - **Gender:** Women have lower BP than men, which increases after menopause due to decreased estrogen levels. - **Diumal Rhythm:** BP decreases 10-20mmHg during sleep and increases in the morning. It reaches its peak in the afternoon. - **Exercise:** Muscular exertion temporarily increases BP, while normal decreases. - **Emotions:** - They cause vasoconstriction and stimulate the sympathetic nervous system, which increases BP. - Severe pain though might decrease BP by inhibiting the vasomotor center. - **Fever:** BP increases due to increased metabolism. - **Bleeding:** BP decreases. - **Heat/Cold:** Heat decreases BP while cold increases BP. - **Obesity:** Increased BP. ### Lifestyle Factors Affecting Blood Pressure - Smoking, alcohol, excessive sodium intake, increase BP as they lead to vasoconstriction. - After smoking, BP returns to baseline after 15 minutes. ### Medication Affecting Blood Pressure - Intravenous fluids increase BP. - Diuretics, cardiac medication decrease BP. ### Blood Pressure Measurement Sites - **Brachial artery:** Used most commonly. - **Popliteal artery:** Used when brachial artery is not accessible such as: - In cases of burns, trauma etc. - Contraindications: amputation, edema, infections etc. - **Radial/Tibial pedis:** Less used, measure only systolic reading. ### BP Measurement Methods - **Direct (Invasive):** - Involves inserting a catheter with an electronic sensor in the artery, which then measures systolic and diastolic pressures directly. - Used in intensive care, coronary care units, emergencies. - **Indirect (Non-invasive):** - **Palpation Method:** - Used when blood pressure in a patient is taken for the first time or when Korotkoff sounds aren't hearable such as in case of severe blood loss, decreased heart contractility, shock. - It measures only systolic pressure. - Requires a sphygmomanometer and a cuff. - **Auscultation Method:** - The standard method for detecting Korotkoff sounds. - Requires a cuff, a sphygmomanometer, and a stethoscope. - **Oscillometric Method:** - Measures BP by measuring oscillations of artery walls. - After pressure in the cuff is released, blood starts flowing through the artery and vibrations arise, corresponding to Korotkoff sounds. - It requires a digital blood pressure monitor. - **Ultrasound Method:** - Measures systolic pressure. - Used when Korotkoff sounds are difficult to detect. - Doppler ultrasound machine detects the movement of red blood cells and converts it to an accurate signal. - **Cardiac monitoring:** ### Blood Pressure Devices - **Aneroid sphygmomanometer:** - Before using it, the needle must point to zero. - Needs biomedical calibration every 6 months. - Consists of a gauge with a needle, a cuff, a bulb, and 1 tube. - **Digital BP monitor:** - Automatic: Automatic cuff inflation. - Semi-automatic: Manual inflation of air through the bulb. - Shows: SP, DP, MAP, pulse rate/heart rate. - Needs regular recalibration for accuracy. - **Automated-auscultatory/hybrid sphygmomanometer:** - Combines auscultatory and oscillometric methods. - Has a mercury free BP method. - Uses a digital display instead of a mercury column. - BP is measured by listening to sounds with a stethoscope. - **Portable Doppler ultrasound:** - Used when pulse sounds are hard to hear e.g. muscular dystrophy. - Measures systolic pressure by Doppler phase shift. - BP is recorded once the motion of arterial wall diminishes. ### Korotkoff Sounds | I | Clear, rhythmical tapping indicating systolic pressure | |---|---| | II | Soft, swishing blowing due to turbulence in blood flow | | III | Sharp sounds (not as sharp as first) where blood flow increases | | IV | Low-pitched sound as pressure in cuff falls below vessel wall pressure | | V | Silence, indicating diastolic pressure in adolescents and adults | | | For children < 13 years and people who exercise, pregnant, hypothyroid, show diastolic pressure | ### Overview - **1 sound**: Systolic pressure, clear sound. - **5 sound**: Diastolic pressure for adults and adolescents, silence. - **4 sound**: Diastolic pressure for children < 13 years, pregnant women, people who exercise, or have hyperthyroid. It's a low-pitched sound. - **Usually:** - **Systolic pressure:** 120 mmHg. - **Diastolic pressure:** 75 mmHg. ### Auscultatory Gap - During the measurement of BP with this process, an auscultatory gap can occur due to venous pooling, obesity, hypertension, carotid atherosclerosis. - Auscultatory gap (silent interval): Temporary silent interval after the first Korotkoff sound and before the second sound. ### To Prevent Auscultatory Gap - To prevent this gap we measure systolic pressure by palpation on radial artery and we inflate the cuff 30mmHg more than the systolic pressure value.