Circulatory System

Defibrillator

ECG Unit

Heart Pump

Hermatology Analyzer

Pulse Oximeter

Sphygmananometer

MRI

Usage: Most commonly by wrapping the patient's arm with a band, and then squeezing to alter the pressure

Portable: Yes

Parts of Machine: (For mercurial type)

• Arm band
• Tube with bulb

A rubber bag is attached to the patient's upper arm and secured with Velcro. The rubber bag is then inflated be squeezing the bulb until the pressure exceeds arterial pressure. To know when this occurs, a stethoscope is placed over the brachial artery below the elbow since no sound is heard from a closed artery.

A valve adjacent to the bulb is then partially opened such that the bag deflates slowly. The first sound produced by the artery is heard when the applied pressure fails to suppress blood flow from the artery, at which the pressure is noted.

The pressure continues to fall until it fails to stop even the lowest point of the arterial pressure cycle. This has to be done by a trained operator of the machine, who will instantly recognize the characteristic, Korotkoff sounds, at this point.

The 2 pressures recorded are then the systolic and diastolic blood pressure, which fall around 120 to 80 mmHG respectively.

Other electronic versions of the device which automate the application and deapplication of pressure have been developed for home use or for use in intensive care, where the patient is generally immobile.

• Relatively cheap
• Portable

• Mercurial version requires the operation of a trained technician