RESUMO
BACKGROUND: According to Schmelzeisen et al. (1996), the failure rate for microvascular free flaps is 5%. While surface tissue oxygenation can be assessed clinically, if necessary by a puncture, the oxygen supply to deeper areas mostly cannot be checked. We therefore wished to find whether measurement of tissue pO(2) would prove to be an objective and practical technique that could be used for continuous and accurate intra- and postoperative evaluation of flap perfusion. MATERIAL AND METHODS: A Clark-type microcatheter was used intra- and postoperatively to monitor tissue pO(2) in 5 pedicled pectoralis major flaps and 32 free revascularized flaps (9 jejunal flaps, 5 latissimus dorsi flaps, 6 radial forearm flaps and 12 scapular flaps). RESULTS: The mean values for tissue pO(2) were significantly lower in pedicle grafts than in free revascularized flaps. Within in each flap group the pO(2) values measured did not vary significantly over an observation period of up to 77.2 h after transplantation. CONCLUSIONS: Continuous measurement of tissue pO(2) by means of a Clark-type microcatheter combined with clinical examination constitutes a reliable method of monitoring tissue oxygenation in pedicle grafts and free revascularized flaps during the intra- and postoperative phases. Analysis of small and of wide fluctuations in pO(2) values may help in the diagnosis of early arterial and venous obstructions in flaps and may in the future result in new insights into the tissue oxygenation in surgical flaps allowing some alleviation of the problems currently experienced in clinical monitoring.
