Objective This study aims to investigate the variations in publicly available nasal irrigation recipes published in the United Kingdom (UK). Design Internet searches used to identify eligible nasal irrigation recipes. These were then examined for their physical and biochemical properties, through theoretical calculations and experimental measurement. Setting Recipes produced by healthcare providers or official national bodies in the UK. Participants No human participants. Main outcome measures Solution osmolality (classified into hypo‐, iso‐ and hypertonic), acidity (pH) and specific gravity. Results Thirteen unique recipes were identified from 17 sources. Osmolality ranged from 166.2 to 1492.2 mosmol/kg in volumes ranging from 142 to 1136 mLs (isotonic range 275‐295 mosmol/kg). Specific gravity ranged from 1.006 to 1.034. pH ranged from 7.74 to 8.11. No recipe produced a solution with isotonic properties. The majority produced hypertonic irrigations. Conclusions Most publicly available nasal irrigation recipes produce hypertonic solutions but there is great variability in the osmolality and volume. UK organisations should take action to review published recipes to bring these into alignment with latest guidelines (recommending against hypertonic saline use) and reduce variability in patient interpretations.

Objective Make-at-home nasal irrigation solutions are often recommended for treating chronic rhinosinusitis. Many patients will store pre-made solution for convenient use. This study investigated the microbiological properties of differing recipes and storage temperatures. Method Three irrigation recipes (containing sodium chloride, sodium bicarbonate and sucrose) were stored at 5oC and 22oC. Further samples were inoculated with Staphylococcus aureus and Pseudomonas aeruginosa. Sampling and culturing were conducted at intervals from day 0–12 to examine for bacterial presence or persistence. Results No significant bacterial growth was detected in any control solution stored at 5oC. Saline solutions remained relatively bacterial free, with poor survival of inoculated bacteria, which may be related to either lower pH or lower osmolality. Storing at room temperature increased the risk of contamination in control samples, particularly from pseudomonas. Conclusion If refrigerated, pre-made nasal irrigation solutions can be stored safely for up to 12 days without risking cross-contamination to irrigation equipment or patients.

No abstract