The "nasal pool"-device for challenge and lavage of the nasal mucosa in children: histamine-induced plasma exudation responses.

The accessibility of the nasal airway allows important examination of the airway mucosa in health and disease. However, the current methods for nasal challenge and lavage in children suffer from several shortcomings. In the present study, we have assessed the utility of a recently developed "nasal pool"-device in 7-9 year old children, and explored the ability of the nasal mucosa of these school-children to mount a plasma exudation response (lumenal entry of bulk plasma). Isotonic saline was instilled and maintained (1 min) as a "pool" in the unilateral nasal cavity. Recovery of the "pool" (lavage fluids) was determined. Concomitant challenge and lavage was then performed by exposing the nasal mucosa to a "pool" of isotonic saline and histamine (40-400 micrograms/ml) for 2 min. "Pool" fluids were analysed for alpha 2-macroglobulin as an index of microvascular-epithelial exudation of bulk plasma. The school-children successfully managed to carry out nasal lavages as well as concomitant histamine challenges and lavages with the "nasal pool"-device. The recovery of the nasal lavage fluids was almost quantitative (> 85%) and thus well reproducible. Histamine produced significant exudation of bulk plasma (alpha 2-macroglobulin). We suggest that the "nasal pool"-device is well suited for challenge and lavage of the nasal airway mucosa in children above 6 years of age, and conclude that lumenal entry of multipotent humoural protein-systems may be an important first line respiratory defence mechanism in children.