A randomized, double-blind, placebo-controlled trial evaluated whether environmental control with nocturnal temperature controlled laminar airflow (TLA) treatment could improve the quality of life of 300 patients aged 7–70 with inadequately controlled persistent atopic asthma in 19 European asthma clinics. TLA devices were installed in the bedrooms of patients to provide a stream of cool air above their heads (see the video embedded below).
The manufacturer advertises the device, called Protexo, as "treatment for patients with atopic asthma without side-effects" (video).
There was a statistically significant difference in treatment response rate between active (76%) and placebo (61%) groups (p=0.02). There was also a difference between groups in fractional exhaled nitric oxide (FeNO) change of −7.1 ppb (p=0.03). Interestingly, the nocturnal temperature controlled laminar airflow (TLA) was associated with less increase in cat-specific IgE than placebo.
The study authors concluded that TLA improves quality of life, airway inflammation and systemic allergy in patients with persistent atopic asthma. Even if the benefits of TLA are confirmed in future trials, the expected relatively high cost of the device (Protexo) may be problematic. A similar device (Opragon) by the same Swedish company (Airsonett) is used to reduce surgical site infections. Neither device is available in the U.S.
Nocturnal temperature controlled laminar airflow for treating atopic asthma: a randomised controlled trial. Thorax doi:10.1136/thoraxjnl-2011-200665 (full text)
Comments from Twitter:
Jennifer Gunter @DrJenGunter: re: cool air device, is that like heading for "sea air" as docs of yore recommended?
@Allergy: Protexo is a bit different - it probably changes the exposure to indoor rather than outdoor allergens