MICROTEK PULSE OXIMETER

🧠 Theoretical Working Principle:-

Pulse oximetry is based on two key principles:

1. Light Absorption Differences Oxygenated hemoglobin (HbO₂) and deoxygenated hemoglobin (Hb) absorb light differently at specific wavelengths:
   • 660 nm (red light): absorbed more by deoxygenated hemoglobin
   • 940 nm (infrared light): absorbed more by oxygenated hemoglobin The oximeter emits both wavelengths through the fingertip and measures the transmitted light using a photodiode.
2. Pulsatile Blood Flow Detection The device detects changes in blood volume during each heartbeat. These fluctuations create a pulsatile signal (AC component) superimposed on a constant background (DC component). The AC signal corresponds to arterial blood, allowing the device to isolate and calculate SpO₂.

⚙️ Core Components and Functionality:-

• LED Emitters: Emit red and infrared light
• Photodiode Sensor: Detects transmitted light intensity
• Microprocessor: Calculates SpO₂ and pulse rate using algorithms
• OLED Display: Shows real-time readings, waveform, and battery status
• Power Control Circuit: Manages battery and auto shut-off
• EEPROM/RAM: Stores calibration and operational data

📊 Calculation Logic:-

The ratio of absorbed red to infrared light is used to estimate oxygen saturation using empirical formulas derived from clinical calibration. The pulse rate is calculated from the frequency of the pulsatile signal.

🧪 Clinical Relevance:-

• SpO₂ < 90%: Indicates hypoxemia
• Normal Range: 95%–99%
• Pulse Rate: Helps monitor cardiac rhythm and detect tachycardia or bradycardia.