Glucose level evaluation in monopedicled rectus abdominis myocutaneous flap after venous occlusion: experimental study in rats

ABSTRACT Objective: to validate an experimental model for the measurement of glycemic levels in surgical flaps with the use of common glucometers, and to analyze the diagnostic criteria for hypoperfusion of such flaps. Methods: we performed vertical myocutaneous rectus abdominis flaps with upper pedicles bilaterally in 20 male Wistar rats, divided into two groups: with and without venous occlusion of the pedicle. We measured glucose levels in the flaps and in the systemic circulation with standard glucometers. We tested the accuracy of alternative diagnostic criteria for the detection of hypoperfusion. Results: from 15 minutes of venous occlusion on, there was a significant reduction in glucose levels measured in the congested flap (p<0.001). Using a minimum difference of 20mg/dl in the glycemic levels between the flap and systemic blood, 30 minutes after occlusion, as a diagnostic criterion, the sensitivity was 100% (95% CI 83.99-100%) and specificity of 90% (95% CI 69.90-97.21%) for the diagnosis of flap congestion. Conclusion: It is possible to measure glucose levels in vertical myocutaneous rectus abdominis flaps of Wistar rats, perfused or congested, using a common glucometer. The diagnostic criteria that compare the glucose levels in the flaps with the systemic ones were more accurate in the evaluation of tissue perfusion.

摘要
目的：验证一种使用普通血糖仪（glucometer）检测外科皮瓣（surgical flap）血糖水平的实验模型，并分析此类皮瓣低灌注（hypoperfusion）的诊断标准。
方法：对20只雄性Wistar大鼠构建双侧带蒂上腹直肌肌皮瓣（vertical myocutaneous rectus abdominis flaps），分为两组：蒂部（pedicle）静脉阻断（venous occlusion）组与非阻断组。采用标准血糖仪分别检测皮瓣及体循环内的血糖水平，并验证用于检测皮瓣低灌注的替代诊断标准的准确性。
结果：静脉阻断15分钟后，充血皮瓣（congested flap）的血糖水平即出现显著下降（p<0.001）。以皮瓣与体循环血糖差值≥20mg/dl作为诊断标准，阻断30分钟后，该标准诊断皮瓣充血的灵敏度（sensitivity）为100%（95%置信区间（confidence interval, CI）：83.99~100%），特异度（specificity）为90%（95%置信区间：69.90~97.21%）。
结论：采用普通血糖仪即可检测Wistar大鼠双侧带蒂上腹直肌肌皮瓣在灌注正常或充血状态下的血糖水平。对比皮瓣与体循环血糖水平的诊断标准，在组织灌注评估中具备更高的准确性。