EFFECT OF HYPERBARIC-OXYGEN ON A RAT TRANSVERSE RECTUS-ABDOMINIS MYOCUTANEOUS FLAP MODEL

The single-pedicle transverse rectus abdominis myocutaneous (TRAM) fla p is frequently associated with partial flap necrosis. Hyperbaric oxyg en has previously been shown to increase the survival of skin flaps, a lthough there has been no investigation of possible beneficial effects of hyperbaric oxygen on survival of the TRAM flap. The present study compares the effectiveness of hyperbaric oxygen therapy, normobaric 10 0% oxygen, a hyperbaric air-equivalent mixture, and no treatment at al l (control group), in the prevention of TRAM flap necrosis in a rat mo del. Forty-eight animals were randomly assigned to one of the four abo ve-mentioned groups. The surviving area of the flap was evaluated 7 da ys after surgery. The hyperbaric oxygen treatment protocol consisted o f five 9-minute sessions breathing 100% oxygen at a pressure of 2.5 at mospheres absolute during the first 48 hours, starting within 1 hour o f surgery. The areas of surviving skin paddles ranged from 38.5 percen t in the control group to 52.5 percent in the group treated with hyper baric oxygen. One-way analysis of variance indicated that flap area su rvival was significantly greater in the hyperbaric oxygen group (F = 2 .69, p = 0.05). Tukey's pairwise comparison and the two-sample t test indicated that the group treated with hyperbaric oxygen differed signi ficantly from the control group (Tukey's critical value = 3.8, rejecti on level = 0.05, t test p = 0.01). Our results suggest that the hyperb aric oxygen treatment protocol used improves survival in the rat TRAM flap. However, the optimal treatment protocol to achieve this objectiv e even in the rat seems to be variable, and further studies are requir ed before extrapolating these data to human applications.