Objective
To evaluate the effect of hyperbaric oxygen (HBO) on muscle flap arterial neutrophil concentration and pulmonary neutrophil sequestration following ischemia-reperfusion injury in a rat gracilis muscle microcirculation model.
Design
Prospective randomized experimental trials.
Setting
Laboratory.
Materials
Male Wistar rats weighing 150 to 300 g.
Interventions
Gracilis muscle flaps were raised on isolated vascular pedicles. Three groups were evaluated: (1) sham (flap raised, 4-hour observation, no ischemia, no HBO), (2) ischemia control (4-hour flap ischemia, no HBO); and (3) ischemia (4-hour flap ischemia) plus HBO (last 90 minutes of ischemia, 100% oxygen, 2.5 atm absolute).
Main Outcome Measures
Flap pedicle arterial leukocyte and neutrophil concentrations were assessed at 5 and 90 minutes of reperfusion in the 3 groups. Pulmonary neutrophil sequestration was measured in a blinded fashion, using histologic examination and myeloperoxidase assay in the 3 groups at 5 and 90 minutes of reperfusions.
Results
Ischemia produced an increase in pedicle arterial leukocyte and neutrophil concentrations in blood flowing to the gracilis muscle flap; administration of HBO significantly reduced concentration to sham levels (P<.05). There were no significant differences in pulmonary neutrophil sequestration among the experimental groups.
Conclusions
In this rat gracilis muscle microcirculation model, the increase in pedicle arterial leukocyte and neutrophil concentrations following ischemia-reperfusion injury was significantly reduced to sham levels by HBO treatment. This observed reduction was not attributable to HBO-induced pulmonary sequestration, which did not significantly change with HBO administration. Further investigation is required to elucidate the mechanisms of action of HBO in ameliorating ischemia-reperfusion injury in this model.
Arch Surg. 1996;131:756-760
