TcPO2 and TcPCO2 monitoring for free flap perfusion assessment

Free flap transplantation has emerged as a prevalent technique in reconstructive surgery for patients with oral cancer. Postoperative monitoring of flap perfusion is critical for flap survival, necessitating early detection and timely intervention. Developing a monitoring approach that is highly sensitive, specific, non-invasive, continuous, and cost-effective is crucial for accurately assessing flap perfusion and informing clinical decisions. From April 2024 to December 2024, 20 patients with oral tumors requiring flap transplantation were enrolled at the Ninth People’s Hospital affiliated to Shanghai Jiao Tong University School of Medicine. Continuous monitoring of various free flaps was performed utilizing a transcutaneous blood gas analyzer, both before and after surgery. This approach allowed for real-time measurement of transcutaneous partial pressure of oxygen (TcPO 2 ) and transcutaneous partial pressure of carbon dioxide (TcPCO 2 ), facilitating the evaluation of perfusion dynamics across various free flap types. After free flap transplantation, a reduction in blood supply resulted in a rapid decline in TcPO 2 (to below 10 ​mmHg), accompanied by a gradual increase in TcPCO 2 , peaking at 135 ​mmHg. Following vascular anastomosis and blood flow restoration, TcPO 2 and TcPCO 2 exhibited opposite trends. Statistical analysis revealed no significant differences in TcPO 2 and TcPCO 2 measurements among the various flap types ( P <0.05), indicating a consistent pattern of change across all flaps. The transcutaneous blood gas analyzer proves to be a reliable method for monitoring free flap perfusion. Dynamic changes in TcPO 2 and TcPCO 2 effectively reflect blood supply status, enabling early detection of vascular compromise and potentially enhancing flap preservation outcomes. ChiCTR, ChiCTR2400086395. Registered March 4, 2024. Prospective registration. https://www.medicalresearch.org.cn/&nearr;ChiCTR2400086395 .