[Transcutaneous oxygen partial pressure in the evaluation of circulatory disorders in myocutaneous island flaps in the rat].

In rectus abdominis myocutaneous island flaps (3.0 x 1.5 cm) of 86 rats (Uje: WIST) transcutaneous oxygen tension measurements (tcPO2) were made by a Universal-PO2-Meter MO 10.1 (PRACITRONIC, Dresden, GDR) for monitoring flap viability following blood flow insufficiency produced experimentally. This insufficiency was induced by ligation of the pedicle vessels (superior epigastric artery and vein) on the 3rd, 4th, 5th and 7th day after flap reposition and by occlusion of these vessels with microclips for two hours. Only the tcpO2 differences between the intact skin and the contralateral myocutaneous island flap were used to assess effects on blood flow and not the absolute values. These differences were statistically insignificant between the right and left non-operated abdominal skin (0.24 +/- 0.11 kPa), the non-operated skin and the rectus abdominis myocutaneous island flap with intact pedicle vessels (group 2) (0.59 +/- 0.14 kPa) as well as flaps ligated at 5-days (0.71 +/- 0.18 kPa) in which vascular pedicle ligation were induced following incision of the cranial flap border. In the two-hour-ischemia group, the 3-days, 4-days and 7-days ligation groups the average tcpO2 differences were greater (1.17 +/- 0.40; 1.58 +/- 0.31; 1.24 +/- 0.22; 1.22 +/- 0.28 kPa) and statistically significant (p less than 0.05) in comparison to the myocutaneous flaps of group 2. Transcutaneous oxygen tension monitoring was useless in predicting flap survival in later postoperative blood flow insufficiency and in assessing the neovascularization. Only during the intraoperative manipulations or the early postoperative period (24 h) tcpO2 monitoring was valuable in assessing the blood supply of myocutaneous flaps in rats.