Study on the reliability of NIRS to monitor fibular flaps on Rhesus monkeys

Objective To confirm the sensitivity and validity of near-infrared spectroscopy (NIRS) technology to detect the dynamic changes of blood volume and regional tissue oxygen saturation (rSO2). Methods Six fibular flaps on Rhesus monkeys were raised simulating a clinical operation. Third generation of NIRS oxygen saturation oximeter (TSAH-100) was employed on Rhesus monkeys’ fibular flaps when its dominant artery and vein were blocked respectively or simultaneously, and then their relative changes of blood volume and oxygen saturation were observed and recorded in June, 2008 to October, 2008. Results The statistic results showed that concentration of deoxygenated hemoglobin (cHb), concentration of oxyhemoglobin (cHbO2) and rSO2 had rapid, apparent and distinct changes respectively in the case of arterial occlusion, venous occlusion and total occlusion. The initial values of cHb and cHbO2 of 3 models were 0 μmol/L. Meanwhile, the initial values of rSO2 in artery embolism, vein embolism and arteriovenous embolism were 51.6%, 54.3% and 56.8%, respectively. The maximum variations of cHb, cHbO2 and rSO2 in 3 models indicated significant difference compared with initial values (P<0.05) , the values of rSO2 after 6 s, 18 s and 8 s in 3 models had significant difference compared with initial values respectively (P<0.05) . Conclusion The TSAH-100 based on NIRS technology is an extraordinarily sensitive and reliable method to monitor the changes of oxygen saturation and blood perfusion in local tissue for buried flap within a depth of 2.0 cm. Key words: Near-infrared spectroscopy (NIRS); Oxygen saturation; Fibular flap; Buried flap; Rhesus monkey