Experimental Animal Study Of A New Infrared Thermographic Blood Flow Monitor In Postoperative Blood Supply Monitoring After Free Flap Repair

Objective: To investigate the application of a homemade hemodynamic monitor based on Infrared Thermography(IRT)in the application of hemodynamic monitoring after free flap repair in an animal model compared to traditional clinical observation methods.Methods: The dorsalis muscle flaps were prepared by 12 small Zangxiang pigs to simulate arterial crisis and venous crisis,respectively,and the blood flow of the flaps was monitored using Laser Doppler Flowmetry(LDF),IRT hemodynamic monitor and clinical observation,respectively,with a 40%decrease in blood flow,a temperature difference between the flap and the surrounding skin up to 3°C,and clinical observation report The time of blood flow obstruction was used as the comparative index of blood flow monitoring.Paired t-test was used to test the feasibility and practicality of the IRT hemodynamic monitor with LDF and clinical observation results,respectively.p< 0.05 indicates that the difference is statistically significant.Result: The time to determine hemodynamic disturbance by IRT hemodynamic monitor was 28.75±3.30 minutes and 96.5±27.09 minutes for the arterial and venous groups,respectively;the LDF was 6.00±1.41 minutes and 52.75±15.76 minutes;the time to determine hemodynamic disturbance by clinical observation was 42.00 ± 8.60 minutes and 156.50 ± 40.91 minutes,respectively.Paired t-test was performed by grouping the time of hemodynamic disturbance reported by IRT hemodynamic monitor with the time of hemodynamic disturbance obtained from clinical observation.The statistical results were significantly different in the arterial group(P < 0.05)and not significantly different in the venous group(P = 0.076),and the IRT hemodynamic monitor was superior to clinical observation in determining the time to impaired hemodynamics in all experimental pig flaps.The IRT hemodynamic monitor was superior to clinical observation in terms of the workload of observing hemodynamics.The time to dyscrasia reported by the IRT hemodynamic monitor was significantly different from the time to dyscrasia obtained by the LDF in the arterial group only(P < 0.05),but not in the venous group(P = 0.791),and the LDF was superior to the IRT hemodynamic monitor as the gold standard for hemodynamic monitoring in determining the time to dyscrasia in any vascular group.The IRT hemodynamic monitor was superior to the LDF in terms of the amount of work required to observe hemodynamics.Conclusion: The new IRT hemodynamic monitor can detect hemodynamic disorders earlier than the traditional clinical observation in the hemodynamic monitoring of the experimental porcine free flap model,which provides the basis of animal experimental data for the application of the new IRT hemodynamic monitor to clinical hemodynamic monitoring of the flap.