Nasal obstruction may be associated with worsening obstructive sleep apnea indicators.
Investigators searched PubMed, MEDLINE, Web of Science, Cochrane, and CINAHL for studies examining the effects of nasal obstruction or mouth taping on obstructive sleep apnea (OSA) indicators. The review included 17 studies and 354 adult participants with or without OSA. Among the studies, 15 (n = 304) were included in the meta-analysis of nasal obstruction. The remaining 2 studies, involving patients with mild OSA, evaluated mouth taping and were reviewed narratively because the data were insufficient for meta-analysis.
Eligible studies compared at least 1 night with surgically or nonsurgically induced nasal obstruction, or mouth taping that promoted nasal breathing, with at least 1 night of usual breathing. Outcomes included the Apnea-Hypopnea Index (AHI), Oxygen Desaturation Index (ODI), and average and nadir oxygen saturation. Random-effects meta-analyses were conducted when at least 3 studies reported sufficiently comparable outcomes.
Across 8 studies with 133 observations, nasal obstruction was associated with a mean AHI increase of 13.78 events per hour. The increase differed according to baseline AHI: among participants with a baseline AHI below 5, nasal obstruction was associated with an increase of 9.56 events per hour vs. 24.11 events per hour among those with a baseline AHI of 5 or more.
Nasal obstruction was also associated with a mean ODI increase of 7.45 events per hour across 5 studies with 164 observations, an increase that was not statistically significant.
Average oxygen saturation decreased by 0.70 percentage points across 5 studies with 97 observations, and nadir oxygen saturation decreased by 1.75 percentage points across 8 studies with 207 observations. Although statistically significant, the investigators characterized these reductions as not clinically meaningful in the context of oxygenation.
The association between nasal obstruction and AHI did not differ significantly between surgical and nonsurgical settings. AHI increased by 15.78 events per hour in the nonsurgical subgroup vs. 12.74 events per hour in the surgical subgroup, although the surgical estimate was less precise. Similarly, the investigators found no statistically significant subgroup difference in ODI according to type of obstruction.
Both mouth taping studies were rated as fair quality. In 1 study involving 20 patients, median AHI decreased from 8.3 to 4.7 events per hour with mouth taping. In the second study involving 30 patients, median AHI decreased from 12.0 to 7.8 events per hour. Neither study had a statistically significant improvement in oxygen saturation. The investigators noted that the small evidence base prevented quantitative synthesis.
Several limitations tempered the findings. Most included studies were observational, limiting causal interpretation, and study populations and methods varied substantially. Definitions of hypopnea were also inconsistent, potentially affecting pooled estimates. Just 3 studies were rated as good quality, 8 as fair, and 6 as poor.
The findings indicated that acute nasal obstruction was associated with worsening sleep apnea indicators and could produce OSA-like abnormalities in otherwise healthy adults. Evidence suggesting a potential benefit from mouth taping was preliminary, and the authors emphasized that the absence of large-scale studies and comprehensive safety data currently limits its clinical application.
“Because the available evidence is largely from observational studies and heterogeneous groups, causal inference should be drawn with caution,” wrote lead study author Nawaf A. Alshehri, MBBS, of the College of Medicine at the King Saud University in Saudi Arabia, and colleagues.
The study authors reported no conflicts of interest.
Source: OTO Open