Effects of cold water immersion on edema formation after blunt injury to the hind limbs of rats

Objective: Despite the long history of using cryotherapy to control edema, we found no randomized, controlled studies providing evidence to substantiate this common clinical practice. The purpose of this study was to determine whether cold water immersion affects edema formation following blunt injuries in rats. Design and Setting: The feet of 16 rats were traumatized after hind limb volumes were determined. Four 30-minute treatments of cold water immersion (12.8°C to 15.6°C, 55°F to 60°F), interspersed with four 30-minute rest periods, began immediately after trauma to one randomly selected hind limb of each rat. The limb remained in a dependent position during all treatments, rest periods, and volumetric measurements. Subjects: Sixteen anesthetized Zucker Lean rats were used in the study. Measurements: Limb volumes were measured after each treatment and rest period for a total of 4 hours. Results: The volume of treated limbs was significantly smaller (p < .05) than the volume of untreated limbs after the first treatment and remained smaller throughout the experiment. Conclusions: Immersing rat limbs in 12.8°C to 15.6°C (55°F to 60°F) water immediately after blunt injury was effective in curbing edema formation.