Effect of tissue perfusion and oxygenation on accumulation of collagen in healing wounds. Randomized study in patients after major abdominal operations.

Objective: To compare the accumulation of collagen in standardised wounds in patients who had abdominal operations and whose postoperative fluid replacement was decided either clinically or by measurements of subcutaneous oxygen tension (PscO2).
Design: Prospective randomised trial.
Setting: University Hospital.
Subjects: Twenty-nine patients with cancer or inflammatory bowel disease who were undergoing abdominal operations.
Interventions: Silicone rubber catheter placed in the upper arm to measure PscO2. Two tubes of expanded polytetrafluoroethylene (ePTFE) implanted subcutaneously parallel to the silicone rubber catheter to measure the amount of collagen accumulated.
Main Outcome Measures: Amount of postoperative fluid replacement required in each group, and measurements of hydroxyproline/cm of the ePTFE tubes.
Results: The group treated according to PscO2 measurements received more fluid on the day of operation than the group treated according to clinical criteria (p < 0.05). They had accumulated more collagen in their ePTFE tubes by day 7 (p < 0.05).
Conclusion: Replacement of fluid according to measurements of PscO2 rather than by clinical criteria results in improved accumulation of collagen in healing wounds.