DIY Flap Monitoring: The Glucose Index

Abstract

Background: Flap loss is reduced by monitoring, which detects vascular compromise. Glucose levels vary in suffering flaps; therefore, we aimed to show that monitoring flaps with glucose pinprick test is a cheap, reliable, ubiquitous, and easy method. Methods: We reviewed a prospectively kept database. A pinprick test was performed to measure systemic and flap glucose levels. A glucose index (GI; flap glucose/systemic glucose) was calculated. Comparison between the groups (with occlusive event, and without occlusive event) was done. Results: In total, 32 flaps in 29 consecutive patients were included. Eleven (34%) were free flaps. Of these, one (9%) was explored twice. Initially, salvage was achieved. However, 36 hours later, a second exploration was needed but was unsuccessful. Of the 21 pedicled flaps (66%), one (5%) needed exploration (suture release), and three (14%) had partial losses that were not clinically relevant. On the ROC curve, we found a cut-off value for a GI of 0.49 or less with a sensitivity of 95% [95% confidence interval (CI): 75.1 to 99.9%] and a specificity of 100% (95% CI: 98.5 to 100%), with a positive predictive value of 100% (95% CI: 81.5 to 100%) and a negative predictive value of 99.6% (95% CI: 97.8 to 100%) for flap suffering. Conclusions: The GI, as a complement, assists in defining treatment approach. It is an easy, reliable, accessible method that can be performed by nonmedical personnel. Its main drawback is the inability to monitor buried or hard to reach flaps.