Cool-Water Immersion and High-Voltage Electric Stimulation Curb Edema Formation in Rats

Abstract

OBJECTIVE: Although cryotherapy and high-voltage electric stimulation, both alone and in combination, are commonly applied to curb acute edema, little evidence from randomized controlled studies supports these procedures. Our purpose was to examine the effects of cool-water immersion (CWI) at 12.8 degrees C (55 degrees F), cathodal high-voltage pulsed current (CHVPC) at 120 pulses per second and 90% of visible motor threshold, and the combination of CWI and CHVPC (CWI + CHVPC) on edema formation after impact injury to the hind limbs of rats. DESIGN AND SETTING: Both feet of 34 rats were traumatized after hind-limb volumes were determined. Animals were randomly assigned to 1 of 3 groups: CWI (n = 10), CHVPC (n = 10), or CWI + CHVPC (n = 14). One randomly selected hind limb of each rat was exposed to four 30-minute treatments, interspersed with four 30-minute rest periods beginning immediately after posttraumatic limb volumes were determined. Contralateral limbs served as controls. Limbs remained dependent during all treatments, rest periods, and volumetric measurements. SUBJECTS: We used 34 anesthetized Zucker Lean rats in this study. MEASUREMENTS: We measured limb volumes immediately before and after trauma and after each of 4 treatment and rest periods. RESULTS: Volumes of treated limbs of all 3 experimental groups were smaller (P <.05) than those of untreated limbs. No treatment was more effective than another. CONCLUSIONS: Cool-water immersion, cathodal high-voltage electric stimulation, and simultaneous application of these treatments were effective in curbing edema after blunt injury. Combining CWI and CHVPC was not more effective than either CWI or CHVPC alone.

Figures

Figure 1

Treated-limb volumes for all 3 conditions (cool-water immersion, cathodal high-voltage pulsed current, and cool-water immersion plus cathodal high-voltage pulsed current) were smaller than untreated limbs (P < .05).

Figure 2

Limb volumes across time, treated limbs only. Limb volumes across time did not differ among the 3 treatments (P < .05). CWI indicates cool-water immersion; CHVPC, cathodal high-voltage pulsed current, CWI + CHVPC, cool-water immersion plus cathodal high-voltage pulsed current.