RT Journal Article
SR Electronic
T1 Effect of high versus low ambient humidity on the severity of obstructive sleep apnoea
JF Thorax
JO Thorax
FD BMJ Publishing Group Ltd and British Thoracic Society
SP 711
OP 713
DO 10.1136/thx.54.8.711
VO 54
IS 8
A1 Ruzica Jokic
A1 Lal Bhagchandani
A1 Trevor Zintel
A1 Marilyn Baetz
A1 Michael F Fitzpatrick
YR 1999
UL http://thorax.bmj.com/content/54/8/711.abstract
AB BACKGROUND Surface tension forces appear to make a significant contribution to upper airway closure in patients with obstructive sleep apnoea (OSA). It is possible that drying of the upper airway mucosa at night might contribute to these surface tension forces and the severity of OSA might therefore change with alteration of the ambient humidity.METHODS A randomised single blind crossover study of high ambient relative humidity (HRH) versus low ambient relative humidity (LRH) was performed in 12 men of mean (SD) age 49 (9) years with mild OSA (apnoea/hypopnoea index (AHI) 14 (5.2)). On one night patients slept in continuous HRH (85 (4)%, range 80–93%) and on the other in LRH (16 (4)%, range 11–22%).RESULTS The AHI was similar on the HRH and LRH nights (mean difference 3; 95% CI –2 to 9, p = 0.20) and no statistically significant differences in AHI were observed on the two nights after standardising for body position and sleep stage. Sleep stage distribution and the proportion of time spent in the supine position were similar on the HRH and LRH nights. The number of non-respiratory arousals was also similar on the two nights.CONCLUSION Altering ambient humidity alone has no significant impact on the severity of OSA.