Flap Blood Glucose as a Sensitive and Specific Indicator for Flap Venous Congestion: A Rodent Model Study

Background: Flap blood glucose decreases when flap congestion occurs. The hypothesis that flap blood glucose works as an indicator for venous congestion was tested experimentally, and flap congestion was reproduced in rodent models. Methods: Blood glucose levels of a rat abdominal skin flap, with or without its vein pedicle clamped, were checked before and every 10 minutes after flap elevation. In rats whose pedicle vein was shut off, it was further followed up every 5 minutes after declamping. To examine the effect of systemic blood glucose on flap blood glucose, in some rats, glucose solution was administered intraperitoneally before the experiment to artificially produce hyperglycemia. Forty-two rats were divided into four groups, with (n = 24) or without (n = 18) venous blockage and with (n = 20) or without (n = 22) glucose preloading. Results: Flap blood glucose decreased rapidly to off-scale low (<20 mg/dl) within 40 minutes only when the vein pedicle was shut off in normoglycemic (40 ± 8.2 minutes, mean ± SD) and hyperglycemic (40 ± 9.9 minutes) rat groups (p < 0.01). There was no significant difference in the time taken for the flap blood glucose to decrease to off-scale low after venous blockage between both groups (p = 0.379). When the vein was declamped, flap blood glucose again rapidly returned to the systemic level in 15 minutes or earlier in both groups (p = 0.0283). Conclusions: Flap blood glucose sensitively and specifically reflects the state of vein occlusion, whether the systemic blood glucose is normal or high. The authors’ results indicate that flap blood glucose works as a reliable indicator for the venous system.