Evaluation of post-operative blood glucose monitoring as a objective tool for flap monitoring

Abstract

Traditionally, clinical monitoring of free flaps in the postoperative period requires a clinician to monitor the flap’s physical characteristics, capillary refill time, temperature, bleeding characteristics after a pin prick, external or handheld Doppler ultrasound device or a combination of these approaches. The objective of this study was to evaluate post operative blood glucose monitoting within flap as a tool that can help in early detection of flap compromise. We performed 25 free flaps on patients aged between 18yrs to 65yrs. GRBS was checked at the finger tip of the patient and simultaneously flap is scratched and GRBS is noted. Blood glucose monitoring done at 6, 12, 18, 24 and 48 hours post operative using blood glucometer. Regular examination for clinical signs of vascular compromise was done to determine flap viability for up to 7th day after operation. Total of the 25 flaps, 20 (80%) were performed on men and the mean age ¬¬of the patients was 47.68years. Considering cut-off value for the mean blood glucose level was set at 62 mg/dL based on receiver operative characteristics (ROC) curve, true positive and false positive cases were 20 and 0 respectively, whereas true negative and false negative cases were 4 and 0 respectively. The sensitivity and specificity are 100% each. Hence we conclude that blood glucose monitoring within flap is easy diagnostic tool and should be used to detect early vascular compromise so that salvage surgery is possible.