The effects of hyperbaric oxygen on normal and ischemic colon anastomoses

BACKGROUND: Leakage from colonic anastomoses is a major complication causing increased mortality and morbidity, and ischemia is a well-known cause of this event. Inadequate tissue oxygenation could be reversed by using hyperbaric oxygen. This study was designed to investigate the effects of hyperbaric oxygen on the healing of ischemic and normal colon anastomoses in the rat model. METHODS: Standardized left colon resection 3 cm above the peritoneal reflection and colonic anastomosis were performed in 40 Wistar rats divided into four groups. The control group (I) received no further treatment. To mimic ischemia, 2 cm mesocolon was ligated on either site of the anastomosis in group II and IV rats. Hyperbaric oxygen therapy was started immediately after surgery in group III and IV rats (therapeutic groups). All animals were sacrificed on the fourth postoperative day. After careful relaparotomy, in situ bursting pressure was measured. The hydroxyproline contents of the anastomotic segments in equal length were determined. RESULTS: The hydroxyproline assay revealed that rats in group II with ischemic colonic anastomosis have significantly lower levels (P <0.05). The highest levels are in the group III rats with normal colonic anastomosis treated by hyperbaric oxygen (P <0.05). There was no significant difference in hydroxyproline levels between group II and group IV animals (P >0.05). Group III animals had significantly higher bursting pressures than any other group (P <0.05). Group II rats had lowest bursting pressures (P <0.05). Group IV animals had significantly higher levels than group II (P <0.05). Mean bursting pressure values both in groups III and IV and hydroxyproline levels in group III were significantly increased by hyperbaric oxygen therapy (P <0.05). CONCLUSIONS: Ischemia impairs anastomotic healing. Hyperbaric oxygen increases anastomotic healing of both normal and ischemic colonic anastomosis and reverses ischemic damage. This study demonstrated that hyperbaric oxygen improves anastomotic healing.