Biomedical Measurement Techniques: Pressure, Flow, and ECG

Direct Blood Pressure Measurement

This method involves inserting a tube or catheter directly into the blood vessel. The catheter is connected to a blood pressure transducer, which generates a corresponding electrical signal. This method is classified into two types:

  1. Extra-vascular pressure sensor
  2. Intra-vascular pressure sensor

Indirect Blood Pressure Measurement

In this method, external pressure is applied to the artery using an instrument called a sphygmomanometer. There are two main techniques:

  1. Palpatory
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Medical Diagnostic Tests: ECG, Glucometer, MRI, EEG, X-Rays, PET, Ultrasound

Electrocardiogram (ECG)

An electrocardiogram is a painless test that records the electrical activity of the heart. You will be asked to lie down while a healthcare provider attaches small electrodes to your chest. These electrodes are connected by wires to a machine that turns the heart’s electrical signals into wavy lines, which are printed on paper.

These signals show three parameters: P wave, QRS complex, and ST segment. The size of these parameters and the distance between them can reflect:

  • Damage
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Blood Tests: Methods, Analysis, and Safety

Tests on Blood Cells

Blood tests commonly analyze:

  • Red blood cells (RBC): 4.5-5.5 million
  • White blood cells (WBC): 6,000-10,000
  • Blood platelets: 200,000-800,000

Centrifugal Method

By spinning blood in a centrifuge, blood cells sediment at the bottom of the test tube. Most of this column consists of red blood cells, with other cells forming a thin, buffy layer on top. The volume of packed red cells is expressed as a percentage of the total blood volume.

Conductivity (Coulter) Method

This method uses the

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Electric Current Effects on the Human Body

Physiological Phenomena Caused by Electric Current

From 1 to 3 mA: perception. Sensitivity or threshold of 10 to 15 mA: tetanization or contraction of the muscles of the hand and arm, close to 25 mA extends to the thoracic muscles. A box from 50 mA: Atrial heart. What Happens to Time Above and Below 150 ms? For times below 150 ms, no risk, if the intensity does not exceed 300 times higher mA. For 150 ms, no risk, if the intensity does not exceed 30 mA. Sequence of the Effects on the Body Produced

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Medical Tests, Procedures, and Equipment: A Comprehensive Look

Blood Tests

Tests on Blood Cells:

  • Red blood cells (RBC) – 4.5-5.5 million
  • White blood cells (WBC) – 6,000-10,000
  • Blood platelets – 200,000-800,000

Centrifugal Method

By spinning blood in a centrifuge, the blood cells can be sedimented at the bottom of the test tube. Most of this column consists of the red blood cells, with the other cells forming a thin, buffy layer on top of the red cells. The volume of the packed red cells is expressed as a percentage of the total blood volume.

Conductivity (Coulter)

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Arteries of the Human Body: Aortic, Subclavian, Iliac & Femoral

Aorta

The aorta is the largest blood vessel in the human body. The first arteries arising from the aorta are the coronary arteries. The left coronary artery is much more developed than the right. The right coronary artery is posterior, and the left is anterior. The lack of irrigation in the right ventricle (RV) is more bearable and has a better prognosis than the lack of irrigation in the left ventricle (LV). The diaphragm is in contact with the RV, protecting the heart when myocardial cells fail.

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