Near-infrared spectroscopy for monitoring free jejunal flap

Abstract

Although the free jejunal graft is commonly used for reconstruction after resection of a tumor of the pharynx or cervical esophagus, adequate monitoring for detecting graft failure is not available. We employed near-infrared spectroscopy to measure regional oxygen saturation (rSO2) in the graft. In 25 consecutive cases who underwent reconstructive surgery using a free jejunal graft, the feasibility of postoperative rSO2 monitoring was examined along with the changes in rSO2 values following vascular clamping or reperfusion. No operative mortality occurred, and except for one case of subcutaneous hematoma that necessitated evacuation surgery, no complications related to surgery or graft failure occurred. Postoperative rSO2 monitoring was feasible for >50 hours in most cases. It mostly remained >55% with a stable hemoglobin index (HbI) which reflects tissue hemoglobin density. A marked increase in the HbI was noted in a patient with hematoma. Intraoperatively, the rSO2 of intact jejunal tissue was >60% in every case but dropped within a few minutes after arterial clamping because of decreased oxygenated hemoglobin concentration. With venous clamping, the HbI was elevated while the rSO2 remained unchanged or was slightly decreased. Upon graft reperfusion, the rSO2 rapidly recovered in all 18 cases because of the recovery of oxygenated hemoglobin concentrations. The near-infrared spectroscopic assessment sensitively and accurately reflected the condition of the jejunal graft. It appears to be a promising postoperative method for monitoring graft perfusion. An rSO2 value of 55% appears to be an adequate criterion for ischemia.