Pulse oximetry: historical review and Ohmeda functional analysis

Area of Science:

• Medical Devices
• Biomedical Engineering
• Physiological Monitoring

Background:

• Oximetry principles are based on detecting spectral properties of oxygenated and reduced hemoglobin.
• Advancements in in vitro analysis drove the development of in vivo measurement techniques.
• The 1930s-40s saw significant oximetry research, leading to pulse oximeters in the 1970s.

Observation:

• Ohmeda pulse oximeters incorporate unique technological dynamics.
• Microprocessor-controlled sequencing, signal processing, and data validation ensure accurate and stable readings.
• The device analyzes the ratio of pulse-added red and infrared light signals transmitted through tissue.

Findings:

• Arterial oxygen saturation is derived from the light signal ratio.
• Empirically derived constants are used for data manipulation, yielding clinically useful numerical data.
• A photo-plethysmographic waveform display provides real-time signal feedback.

Implications:

• This technology enhances the accuracy and reliability of non-invasive oxygen saturation monitoring.
• The integration of advanced signal processing improves clinical decision-making.
• The man-machine interface, via waveform display, aids in understanding oximeter performance.