Question

PPG is used to measure

• A. pulse rate
• B. ECG
• C. lung volume
• D. EEG

Hint:

PPG is the technology found in modern smartwatches and fitness bands that use green or red light on the wrist to display heart rate and pulse rate.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question asks for the physiological parameter measured using Photoplethysmography (PPG).

Step 2: Detailed Explanation:

• PPG stands for Photoplethysmography. It is a non-invasive, low-cost optical technique used to detect volumetric changes in blood in peripheral circulation.

• A PPG sensor typically consists of a light source (often an LED) and a photodetector.

• Light is shone into the skin, and the amount of light absorbed or reflected by the blood vessels is monitored by the photodetector.

• During each cardiac cycle, the heart pumps blood to the periphery, causing a transient increase in blood volume in the microvascular bed, which absorbs more light.

• This periodic absorption change produces a pulsatile waveform (PPG waveform) that directly corresponds to the heartbeat.

• By measuring the frequency of these peaks over time, the PPG device calculates the patient's pulse rate (or heart rate).

Step 3: Final Answer:
PPG is used to measure the pulse rate.