Free flap pulse oximetry utilizing reflectance photoplethysmography

Area of Science:

• Biomedical Engineering
• Plastic Surgery
• Medical Devices

Background:

• Successful free flap salvage relies on continuous perfusion monitoring.
• Current post-operative monitoring lacks reliable, continuous assessment of free flap blood oxygen saturation.
• Existing methods have limitations in real-time viability assessment.

Purpose of the Study:

• To develop and evaluate a reflectance photoplethysmographic (PPG) system for real-time estimation of arterial oxygen saturation (SpO2) in free flaps.
• To assess the feasibility of using PPG for continuous, non-invasive monitoring of free flap perfusion.
• To overcome limitations of current post-operative free flap monitoring techniques.

Main Methods:

• Development of a reflectance photoplethysmographic (PPG) processing system with real-time SpO2 estimation using LabVIEW.
• Clinical evaluation of the PPG system on five patients undergoing Deep Inferior Epigastric Perforator (DIEP) flap breast reconstruction.
• Simultaneous acquisition of PPG signals from free flaps and patient fingers for comparison.

Main Results:

• Good quality PPG signals were successfully obtained from both free flaps and fingers.
• Estimated SpO2 values from the free flaps showed broad agreement with a commercial pulse oximeter.
• The developed PPG system demonstrated capability for real-time SpO2 estimation.

Conclusions:

• Reflectance free flap photoplethysmography is a viable continuous monitoring technique.
• The system offers a non-invasive method for monitoring free flap perfusion and viability.
• This technology has the potential to improve post-operative care for patients with free flaps.