Influence of intranasal sterile isotonic sea water applications on xylometazoline administration: an experimental study in pigs.

Objective: The aim of this study was to investigate how isotonic sea water solution (Physiomer) affects the structure of porcine nasal mucosa when it is applied simultaneously with vasoconstrictors (xylometazoline) for a prolonged period of time.
Methods: Twenty pigs of the PMR-Landraze breed formed the study group. A solution of xylometazoline 0, 1% (Otrivin spray, Novartis) was sprayed every 8h in both nasal cavities of the pigs, with two applications into each nostril for 28 days. Between the applications (4h later), the right nasal cavity was washed with sterile isotonic sea water (Physiomer Normal, Geomar). Biopsies were taken under endoscopic guidance from the nasal mucosa of each nasal cavity separately at specific times. Five histological parameters were microscopically examined for each biopsy section: (1) inflammation, (2) fibrosis, (3) metaplasia of the epithelium, (4) reactive atypia of the epithelium and (5) necrosis.
Results: Statistically significant differences regarding grade of inflammation on days 7 (p=0.0009), 12 (p=0.01), 20 (p=0.02) and 28 (p=0.0005), regarding grade of fibrosis on day 28 (p=0.026) and regarding epithelial metaplasia on day 5 (p=0.052) were found between the nasal mucosa treated only with vasoconstrictors and the nasal mucosa treated with vasoconstrictors and sea water washing. In all cases, samples from the nasal cavities that had been washed with Physiomer appeared with a lower grade of inflammation, fibrosis and metaplasia compared to the samples from nasal mucosa where no nasal washing was performed.
Conclusion: Nasal irrigations with isotonic sea water, when are applied 4h after vasoconstrictors for a long period of time, prevent nasal mucosa from histological damage.
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