Histological changes in the nasal mucosa after hot-water irrigation. An animal experimental study.

Many years ago the treatment of posterior epistaxis was irrigation with hot water through the bleeding nose cavity, and the treatment was successful in many cases. The aim of this study is to explain how "hot-water irrigation" can cause haemostasis. Twenty-four rabbits were divided into 12 groups and their noses were irrigated for 5 min with hot water at temperatures ranging from 40-60 degrees C. After irrigation, the nose was fixed, sliced, stained, and evaluated blindly by a pathologist. The morphological changes-narrowing of intranasal lumen, vasodilation and stasis, extravasation of erythrocytes, and epithelial necrosis-were recorded. No changes were recorded after irrigation with water of 40-44 degrees C. Only light changes were present in the 46 degrees C group. Vasodilation occurred at a temperature of 48 degrees C or higher. From 48 degrees C, oedema of the mucosa and subsequent narrowing of the intranasal lumen was seen. Severe changes including epithelial necrosis, were found only in the groups treated with 52 degrees C or higher. The results of the study indicate that the haemostatic effect of hot water treatment for epistaxis may be caused by: (1) oedema and narrowing of the intranasal lumen, (2) vasodilation of the mucosal vessels, and (3) cleaning of the nose from blood coagulates.