The effect of prompt local cooling on oedema formation in scalded rat paws.

A standardized, reproducible burn model on rat paw was used and the effect of prompt local cooling on the oedema formation was measured using a newly developed non-invasive method. A transient reduction in oedema formation was observed lasting for a longer period of time with decreasing temperature down to 0 degrees C and increasing cooling time up to 120 min. The decrease in oedema formation was followed by an increase towards or above the amount of oedema in untreated scald injury. This post-cooling increase in oedema formation was related to the temperature and the exposure time of the cooling fluid. The immediate effects of cooling are most likely due to local restriction of the blood flow as a result of cold-induced vasoconstriction. The increase of the oedema formation after the cooling period may be due to reactive hyperaemia.