Trans-nasal high-flow dehumidified air in acute migraine headaches: A randomized controlled trial.

BACKGROUND: Intranasal high flow of dehumidified (dry) air results in evaporative cooling of nasal passages. In this randomized clinical trial, we investigated the effect of dry gas induced nasal cooling on migraine headaches. METHODS: In this single-blind study, acute migraineurs were randomized to either nasal high-flow dry oxygen, dry air, humidified oxygen or humidified air (control) at 15 L/min for 15 min. All gases were delivered at 37°C. Severity of headache and other migraine associated symptoms (International Classification for Headache Disorders, 3rd edition criteria) were recorded before and after therapy. The primary endpoint was change in pain scores, while changes in nausea, photosensitivity and sound sensitivity scores served as secondary endpoints. A linear regression model was employed to estimate the impact of individual treatment components and their individual interactions. RESULTS: Fifty-one patients (48 ± 15 years of age, 82% women) were enrolled. When compared to the control arm (humidified air), all therapeutic arms showed a significantly greater reduction in pain scores (primary endpoint) at 2 h of therapy with dry oxygen (-1.6 [95% CI -2.3, -0.9]), dry air (-1.7 [95% CI -2.6, -0.7)]), and humidified oxygen (-2.3 [95% CI -3.5, -1.1]). A significantly greater reduction in 2-h photosensitivity scores was also noted in all therapeutic arms (-1.8 [95% CI -3.2, -0.4], dry oxygen; -1.7 [95% CI -2.9, -0.4], dry air; (-2.1 [95% CI -3.6, -0.6], humidified oxygen) as compared to controls. The presence of oxygen and dryness were independently associated with significant reductions in pain and photosensitivity scores. No adverse events were reported. CONCLUSION: Trans-nasal high-flow dry gas therapy may have a role in reducing migraine associated pain.Clinical Trial registration: NCT04129567.

Regional peak mucosal cooling predicts the perception of nasal patency.

OBJECTIVES/HYPOTHESIS: Nasal obstruction is the principal symptom that drives patients with rhinosinus disease to seek medical treatment. However, patient perception of obstruction often bears little relationship to actual measured physical obstruction of airflow. This lack of an objective clinical tool hinders effective diagnosis and treatment. Previous work has suggested that the perception of nasal patency may involve nasal trigeminal activation by cool inspiratory airflow; we attempt to derive clinically relevant variables following this phenomenon. STUDY DESIGN: Prospective healthy cohort. METHODS: Twenty-two healthy subjects rated unilateral nasal patency in controlled room air using a visual analog scale, followed by rhinomanometry, acoustic rhinometry, and butanol lateralization thresholds (BLTs). Each subject then immediately underwent a computed tomography scan, enabling the construction of a real-time computational fluid dynamics (CFD) nasal airway model, which was used to simulate nasal mucosa heat loss during steady resting breathing. RESULTS: Among all measured and computed variables, only CFD-simulated peak heat loss posterior to the nasal vestibule significantly correlated with patency ratings (r = -0.46, P < .01). Linear discriminant analysis predicted patency categories with 89% success rate, with BLT and rhinomanometric nasal resistance being two additional significant variables. As validation, CFD simulated nasal resistance significantly correlated with rhinomanometrically measured resistance (r = 0.41, P < .01). CONCLUSIONS: These results reveal that our noses are sensing patency via a mechanism involving localized peak nasal mucosal cooling. The analysis provides a strong rationale for combining the individualized CFD with other objective and neurologic measures to create a novel clinical tool to diagnose nasal obstruction and to predict and evaluate treatment outcomes.