Blood Pressure Monitors - Basics
| What does it do? |
It measures the pressure in the veins or arteries. |
| Physiology |
When the heart beats, it pumps blood to the body through
the arteries. The blood then returns to the heart through
the veins. The amount the heart contracts, the volume of the
blood and the diameter of the blood vessels all determine
the pressure inside the vessels. |
| How it works |
A narrow fluid filled tube is inserted into a blood vessel. The end of the tube is connected to a pressure sensor. The pressure in the vessel pressurises the fluid in the tube and the pressure sensor measures this. The pressure sensor sends an electrical signal to the monitor, which displays the pressure on a screen. |
| An invasive blood pressure machine is also used to measure
other pressures inside the body such as intracranial pressure
(the fluid around the brain), intrapleural (between the lung
tissue and the ribs) and gastro-intestinal pressures (inside
the stomach or intestines) |
|
| Units of measurement |
mmHg |
| Typical values |
Venous: mmHg Systolic: 120 mmHg Diastolic: 80 mmHg Mean arterial: 100 mmHg |
| Picture of equipment | |
 Merlin HP/Philips |