Intra-operative monitoring of the pelvic circulation using a transanal Doppler probe.

The authors have developed a new device to examine the pre-, intra-, and postoperative pelvic blood flow, consisting of a plastic rectoscope with a commercially available 10 MHz flat Doppler probe mounted at the tip surrounded in use by a thin, acoustic gel filled condom and inserted transanally. Blood flow in the superior rectal artery can easily be detected in this way through the posterior wall of the rectum. The authors have used this technique in 70 patients, 49 undergoing abdominal aortic aneurysmectomy and 21 aorto-femoral bypass surgery. In all cases following clamping of the infrarenal aorta a synthetic bifurcated graft was anastomosed usually to the aorta using an end-to-end or end-to-side anastomosis. Immediately after application of the aortic clamp the Doppler recorder was started in order to determine the time when rectal blood flow reappeared. In the superior mesenteric artery dominant group, a good pulse wave was seen within 15 min of clamping and 88% of the aneurysm and 62% of the aorto-iliac patients fell into this group. Fourteen patients in this group underwent triple vessel ligation (bilateral internal iliac and inferior mesenteric arteries) without any postoperative colonic ischaemia. In an additional study consisting of eight patients with vasculogenic impotence and/or hip claudication, the effectiveness of surgery was assessed by the increase in amplitude of the Doppler signals following reconstruction of the internal iliac artery. Following successful internal iliac reconstruction, an improvement in the amplitude of the waveform could be observed and followed postoperatively. In conclusion, the transanal Doppler probe can be used to follow the adequacy of the pelvic circulation allowing safer aorto-iliac and aorto-femoral surgery.