A method for flap monitoring based on bioelectrical-resistance analysis

Axial pattern flaps are characterized by a single vascular pedicle that supplies the whole flap and carry the danger of flap loss. For this reason, monitoring and early identification of vascular perfusion is important for flap prognosis. The most commonly used method for flap monitoring is clinical assessment, but it has certain limitations. The bioelectrical properties of tissues can be affected by ischemic conditions, and a preliminary study showed that the bioelectrical resistance of blood was decreased under thrombotic conditions. In this controlled study, the resistance values of the axial flaps were calculated during thrombosis. A total of 28 rats were randomly divided into a control group (n = 14) and an experimental group (n = 14). Axial flaps were elevated based on the inferior epigastric pedicle. For the ischemic group, microvascular clamps were placed in the ischemic group to produce artificial thrombosis from day 1 of the experiment. Bioelectrical resistance was measured every 30 minutes for the first 6 hours and then daily after that. The resistance values from the ischemic group decreased progressively, and 150 minutes after the clamping, the difference became statistically significant (P < 0.05). The results showed that the assessment of flap resistance is a valuable tool and may allow early recognition of a compromise in the vascular system before clinical signs become obvious.