Prospective analysis of flap perfusion by measuring capillary glucose level in flaps

Abstract

Post-operative monitoring of flap is equally important as harvesting of a flap. Early diagnosis of flap failure can salvage the flap by appropriate intervention. The monitoring methods used should be rapid, inexpensive, and accurate. The purpose of this study is to evaluate the usefulness of blood glucose monitoring (BGM) of the flap as our monitoring modality. This study includes 60 flaps which were monitored by measuring their capillary glucose level by pricking the distal end of the flap. Out of the 60 flaps, 18 were free flaps, 23 were pedicled, and 19 were of the random variety. Quantitative data was expressed in frequency, percentage, mean value, and standard deviation for capillary glucose levels of the flap. Out of the 60 flaps, 44 survived well, 10 flaps were having minor distal necrosis (< 10% of flap area), major flap necrosis occurred in 3 flaps while 3 flaps failed completely. Failed flaps have shown lower glucose levels. Using the receiver operating characteristic curve (ROC), the cutoff value for BGM was 61 mg/dl, with a sensitivity of 93% and a specificity of 80%. Blood glucose monitoring reveals the state of perfusion of the flap in the postoperative period. Flap capillary glucose levels less than 61 mg/dl is suggestive of ischemia of the flap with a sensitivity and a specificity of 93% and 80%, respectively. It has prognostic value as it allows early detection of vascular compromise and also defines the forthcoming line of demarcation in partial necrosis. Level of Evidence: Type IV, diagnostic study.