Effects of Cool-Water Immersion and High-Voltage Electric Stimulation for 3 Continuous Hours on Acute Edema in Rats

Abstract

OBJECTIVE: 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, or the combination of CWI and CHVPC, applied 30 minutes on, 30 minutes off for 4 hours, are known to curb edema formation after blunt trauma to the hind limbs of rats. Our purpose was to examine the effects of extending treatment times to 3 continuous hours after blunt trauma to the hind limbs of rats. DESIGN AND SETTING: A randomized, parallel-groups design of 22 subjects was used. Volumes of traumatized limbs, randomly assigned to CWI (n = 7), CHVPC (n = 8), or CWI followed by CHVPC (n = 7) were compared with those of injured but untreated limbs with analysis of variance. SUBJECTS: Twenty-two anesthetized Zucker lean rats (mass = 293 +/- 27 g). MEASUREMENTS: We measured limb volumes immediately before and after trauma and every 30 minutes over the 4-hour experiment. RESULTS: Volumes of treated limbs of all 3 experimental groups were smaller than those of untreated limbs (P <.05). No treatment was more effective than another. CONCLUSIONS: Exposure to either 3 hours of CWI or CHVPC or to 1 hour of CWI followed by 2 hours of CHVPC effectively curbed edema after blunt injury. These results suggest that these common treatments are effective only during application and hint that application should be maintained throughout the period during which edema is forming.

Figure 1

Volumetric measurement system. Reprinted with permission from Dolan et al.

Figure 2

Volume change in treated versus untreated limbs over time. Limbs treated by cold-water immersion, cathodal high-voltage pulsed current, or cold-water immersion followed by cathodal high-voltage pulsed current were smaller than untreated limbs for all time intervals except at time 0 (P .05).

Figure 3

Volume change by treatment over time. Limbs treated with cold-water immersion (CWI), cathodal high-voltage pulsed current (CHVPC), or cold-water immersion followed by cathodal high-voltage pulsed current (CWI + CHVPC) demonstrated no differences in limb volumes across time among the 3 treatments (P .05).