The Effect of Upper Airway Surgery on Loop Gain in Obstructive Sleep Apnea
Open accessAbstract
Controversy exists as to whether elevated loop gain is a cause or consequence of obstructive sleep apnea (OSA). Upper airway surgery is commonly performed in Asian patients with OSA who have failed positive airway pressure therapy and who are thought to have anatomical predisposition to OSA. We hypothesized that high loop gain would decrease following surgical treatment of OSA due to reduced sleep apnea severity. Polysomnography was performed preoperatively and postoperatively to assess OSA severity in 30 Chinese participants who underwent upper airway surgery. Loop gain was calculated using a validated clinically-applicable method by fitting a feedback control model to airflow. Patients were followed up for a median (interquartile range) of 130 (62, 224) days after surgery. Apnea-hypopnea index (AHI) changed from 60.8 (33.7, 71.7) to 18.4 (9.9, 42.5) events/h (P < .001). Preoperative and postoperative loop gain was 0.70 (0.58, 0.80) and 0.53 (0.46, 0.63) respectively (P < .001). There was a positive association between the decrease in loop gain and the improvement of AHI (P = .025). High loop gain was reduced by surgical treatment of OSA in our cohort. These data suggest that elevated loop gain may be acquired in OSA and may provide mechanistic insight into improvement in OSA with upper airway surgery. Registry: ClinicalTrials.gov, Title: The Impact of Sleep Apnea Treatment on Physiology Traits in Chinese Patients With Obstructive Sleep Apnea, Identifier: NCT02696629, URL: https://clinicaltrials.gov/show/NCT02696629 Li Y, Ye J, Han D, Zhao D, Cao X, Orr J, Jen R, Deacon-Diaz N, Sands SA, Owens R, Malhotra A. The effect of upper airway surgery on loop gain in obstructive sleep apnea. J Clin Sleep Med 2019;15(6):907–913.
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Elevated loop gain has been found to predict failure of sleep apnea surgeries, at least in some cases.
“From a surgical perspective, elevated loop gain may be important since it has been found to predict failure of sleep apnea surgeries, at least in some cases.363–365”
From International Consensus Statement on Obstructive Sleep Apnea (2023) · cites this paper as [364]
The Summary of the Findings (page not available in our copy) identifies high loop gain as a potential reason some patients respond poorly to upper airway surgery. But it presents this as a possible explanation, not a finding that elevated loop gain predicts surgical failure. The Results report an association between changes in loop gain and improvements in apnea severity, rather than a test of preoperative loop gain as a predictor of failure. (LLM, conf=0.83)
Experimental — accuracy not yet measuredSome data suggest that a low arousal threshold may be a risk factor for failure of upper airway surgery to achieve a surgical cure.
“Some data suggest that a low arousal threshold may be a risk factor for failure of UA surgery to achieve a surgical cure.”
From International Consensus Statement on Obstructive Sleep Apnea (2023) · cites this paper as [364]
The Summary of the Findings discusses variable surgical success and identifies high loop gain as a possible contributor to poor response. The Results report surgical outcomes, but neither section links a low arousal threshold to failure to achieve a cure; searches for “low arousal threshold” and “arousal threshold” found no such finding in our copy. Page numbers were unavailable. (LLM, conf=0.74)
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References 27 · Cited by 38
Research works printed but not linked: 4
- [15]15. Jingying Y, Biao Y, Jingming L, et al. Combination of transpalatal advancement pharyngoplasty and H-uvulopalatopharyngoplasty for obstructive sleep apnea. Oper Tech Otolayngol Head Neck Surg. 2009;20:152-158.
- [19]19. Lee RWW, Sutherland K, Sands SA et al. Differences in respiratory arousal threshold in Caucasian and Chinese patients with obstructive sleep apnoea. Respirology. 2017;22:1015-1021.
- [20]20. Eckert DJ, White DP, Jordan AS, Malhotra A, Wellman A. Defining phenotypic causes of obstructive sleep apnea. Identification of novel therapeutic targets. Am J Respir Crit Care Med. 2013;188:996-1004.
- [22]22. Chowdhuri S, Shanidze I, Pierchala L, Belen D, Mateika JH, Badr MS. Effect of episodic hypoxia on the susceptibility to hypocapnic central apnea during NREM sleep. J Appl Physiol (1985). 2010;108:369-377.
- Authors
- Li, Y., Ye, J., Han, D., Zhao, D., Cao, X., Orr, J., Jen, R., Deacon-Diaz, N., Sands, S. A., Owens, R., & Malhotra, A.
- Affiliations
- Beijing Tongren Hospital (CN)
- University of California San Diego (US)
- Brigham and Women's Hospital (US)
- Corresponding author
- Ye, Jingying
- ORCID
- Venue
- Journal of Clinical Sleep Medicine
- Published
- 2019-06-15
- Volume
- 15
- Issue
- 6
- Pages
- 907-913
- ISSN
- 1550-9389 (ISSN-L)
- 1550-9397
- PMC
- PMC6557647
- OpenAlex
- W2952395847
- Semantic Scholar
- 545f24d244f3ad572683233386063562bf1c779f
- Cited by
- 38
- References
- 27
- Citations by year
- 2026: 5 · 2025: 3 · 2024: 7 · 2023: 7 · 2022: 6 · 2021: 4 · 2020: 6
- FWCI
- 2.74
- Type
- journal article
- Language
- en
- Open access
- green
- www.ncbi.nlm.nih.gov
- Locations
- Journal of Clinical Sleep Medicine (publishedVersion)
- PubMed Central (publishedVersion)
- PubMed (publishedVersion)
- eScholarship (California Digital Library) (submittedVersion)
- Funders
- American Heart Association
- American Thoracic Society
- ResMed
- National Natural Science Foundation of China
- University of California, San Diego
- National Heart, Lung, and Blood Institute (R01HL081823, T32HL134632, R21HL121794, R01HL085188, K24HL132105, R01HL119201)
- Topics
- Health Sciences › Medicine › Physiology › Obstructive Sleep Apnea Research
- Life Sciences › Neuroscience › Endocrine and Autonomic Systems › Neuroscience of respiration and sleep
- Social Sciences › Psychology › Experimental and Cognitive Psychology › Sleep and related disorders
- Keywords
- obstructive sleep apnea, upper airway surgery, loop gain, feedback control model, airflow dynamics, apnea-hypopnea index, sleep apnea severity, Chinese patients
- MeSH terms
- Adult, Female, Humans, Male, Middle Aged, Severity of Illness Index, Otorhinolaryngologic Surgical Procedures, Cohort Studies, Treatment Outcome, Polysomnography, Sleep Apnea, Obstructive, Laser Therapy
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