Beneficial effect of hyperbaric oxygen on island flaps subjected to secondary venous ischemia

The potential for hyperbaric oxygen therapy (HBO) to decrease the untoward effects of a secondary ischemic event was studied in the rat superficial epigastric flap model. The secondary venous ischemic flap was created by cross‐clamping the vascular pedicles for 2 h. Twenty‐four hours later, the flap was reelevated and the venous pedicle was occluded for 5 h. Thirty‐two rats were divided into three groups. In experimental group 1, animals received HBO treatment immediately prior to the initial flap elevation and ischemia at 2 atmosphere pressures for 90 min. In experimental group 2, the rats underwent a similar course except for a second 90‐min HBO course immediately prior to the secondary venous occlusion. The rats without HBO therapy were used as controls. The results showed that all control flaps were nonviable at 1 week by clinical inspection and fluorescein injection. Complete flap survival occurred in 20% of group 1 flaps and 30.8% of group 2 flaps. Partial flap survival occurred in the rest of the flaps in these two groups, with mean survival areas of 48% and 55%, respectively. In conclusion, HBO treatments significantly increase the survival of flaps subjected to a secondary ischemia, even if administered before the primary ischemia. Administering HBO prior to secondary venous ischemia was marginal, which may be due to the effect of O 2 given by HBO not lasting longer than 5 h. © 2002 Wiley‐Liss, Inc. MICROSURGERY 22:49–52 2002