Objective: To demonstrate that in comparison to implantable O(2) microelectrodes, capillary blood gas measurements represent a reliable, accessible, and easy method of identifying failing free flaps.
Study design: Groin fasciocutaneous flaps were elevated in 10 rats and following venous occlusion, O(2) microelectrode measurements (pO(2) and flow), and capillary blood gas measurements (pO(2), pCO(2), pH, HCO(3)) were obtained at 10-minute intervals.
Results: Measurements with capillary blood gas paralleled measurements with O(2) microelectrodes. Average capillary blood gas pO(2) fell from 42.71 to 31.57 mm Hg at 10 minutes and then to 28.67 mm Hg at 20 minutes. Average pH fell from 7.38 to 7.33 at 10 minutes and to 7.30 at 20 minutes. Results were statistically significant with both the paired Student's t test and the Wilcoxon signed rank test.
Conclusion: While providing users an ability to simultaneously monitor accepted modalities of flap surveillance, pH and pO(2), capillary blood gas is a reliable, accessible, and reproducible marker of flap health.