Objectives: . Endotype-based interventions have shown promise in the treatment of patients with obstructive sleep apnea, and upper airway surgery is a key therapeutic option. However, responses to surgery vary among patients with obstructive sleep apnea. This study aims to examine changes in endotypic traits following upper airway surgery and to explore their association with surgical outcomes. Methods: . We prospectively recruited 25 patients with obstructive sleep apnea who visited a single sleep center for upper airway surgery. These patients underwent polysomnographic studies both before and after surgical intervention. During non-rapid eye movement and rapid eye movement sleep, we estimated endotypic traits—including collapsibility (Vpassive), arousal threshold, loop gain, and upper airway compensation—with the phenotyping using polysomnography method. Based on improvements in the apnea-hypopnea index, patients were classified as either responders or non-responders. We compared the preoperative endotypic traits between these groups using Mann-Whitney tests. Additionally, we compared changes in endotypic traits pre- and post-surgery between responders and non-responders using generalized linear mixed models. Results: . We identified 12 responders and 13 non-responders. Compared to non-responders, responders exhibited improved collapsibility during rapid eye movement sleep (22.3 vs. −8.2%eupnea in Vpassive, P=0.01), and their arousal threshold decreased during non-rapid eye movement sleep (−22.4%eupnea, P=0.02). No endotypic trait predicted surgical response; however, the apnea-hypopnea index during rapid eye movement sleep was higher among responders than non-responders (51.8/hr vs. 34.4/hr, P=0.05). Conclusion . Upper airway surgery significantly reduced collapsibility during rapid eye movement sleep in responders. The target pathology for upper airway surgery is a compromised upper airway during rapid eye movement sleep.

Background/Aims: Distal mean nocturnal baseline impedance (MNBI) measuring via pH-impedance may be valuable in diagnosing patients with suspected laryngopharyngeal reflux (LPR). However, its wide adoption is hindered by cost and invasiveness. This study investigates whether baseline impedance measured during high-resolution impedance manometry (HRIM-BI) can predict pathological MNBI. Methods: A cross-sectional study in Taiwan included 74 subjects suspected of LPR, who underwent HRIM (MMS) and pH-impedance testing (Diversatek), after stopping proton pump inhibitors for more than 7 days. Subjects with grade C or D esophagitis or Barrett’s esophagus were excluded. The cohort was divided into 2 groups: those with concomitant typical reflux symptoms (CTRS, n = 28) and those with isolated LPR symptoms (ILPRS, n = 46). HRIM-BI measurements focused on both distal and proximal esophagi. Pathological MNBI was identified as values below 2065 Ω, measured 3 cm above the lower esophageal sphincter. Results: In all subjects, distal HRIM-BI values correlated weakly with distal MNBI(r = 0.34-0.39, P < 0.005). However, in patients with ILPRS, distal HRIM-BI corelated moderately with distal MNBI(r = 0.43-0.48, P < 0.005). The areas under the receiver operating characteristic curve was 0.78 (P = 0.001) with a sensitivity of 0.83 and a specificity of 0.68. No correlation exists between distal HRIM-BI and distal MNBI in patients with CTRS, and between proximal HRIM-BI and proximal MNBI in both groups. Conclusions Distal HRIM-BI from HRIM may potentially predict pathological MNBI in patients with ILPRS, but not in those with CTRS. Future outcome studies linked to the metric are warranted.

Objectives: . Endotype-based interventions have shown promise in the treatment of patients with obstructive sleep apnea, and upper airway surgery is a key therapeutic option. However, responses to surgery vary among patients with obstructive sleep apnea. This study aims to examine changes in endotypic traits following upper airway surgery and to explore their association with surgical outcomes. Methods: . We prospectively recruited 25 patients with obstructive sleep apnea who visited a single sleep center for upper airway surgery. These patients underwent polysomnographic studies both before and after surgical intervention. During non-rapid eye movement and rapid eye movement sleep, we estimated endotypic traits—including collapsibility (Vpassive), arousal threshold, loop gain, and upper airway compensation—with the phenotyping using polysomnography method. Based on improvements in the apnea-hypopnea index, patients were classified as either responders or non-responders. We compared the preoperative endotypic traits between these groups using Mann-Whitney tests. Additionally, we compared changes in endotypic traits pre- and post-surgery between responders and non-responders using generalized linear mixed models. Results: . We identified 12 responders and 13 non-responders. Compared to non-responders, responders exhibited improved collapsibility during rapid eye movement sleep (22.3 vs. −8.2%eupnea in Vpassive, P=0.01), and their arousal threshold decreased during non-rapid eye movement sleep (−22.4%eupnea, P=0.02). No endotypic trait predicted surgical response; however, the apnea-hypopnea index during rapid eye movement sleep was higher among responders than non-responders (51.8/hr vs. 34.4/hr, P=0.05). Conclusion . Upper airway surgery significantly reduced collapsibility during rapid eye movement sleep in responders. The target pathology for upper airway surgery is a compromised upper airway during rapid eye movement sleep.

Background/Aims: Distal mean nocturnal baseline impedance (MNBI) measuring via pH-impedance may be valuable in diagnosing patients with suspected laryngopharyngeal reflux (LPR). However, its wide adoption is hindered by cost and invasiveness. This study investigates whether baseline impedance measured during high-resolution impedance manometry (HRIM-BI) can predict pathological MNBI. Methods: A cross-sectional study in Taiwan included 74 subjects suspected of LPR, who underwent HRIM (MMS) and pH-impedance testing (Diversatek), after stopping proton pump inhibitors for more than 7 days. Subjects with grade C or D esophagitis or Barrett’s esophagus were excluded. The cohort was divided into 2 groups: those with concomitant typical reflux symptoms (CTRS, n = 28) and those with isolated LPR symptoms (ILPRS, n = 46). HRIM-BI measurements focused on both distal and proximal esophagi. Pathological MNBI was identified as values below 2065 Ω, measured 3 cm above the lower esophageal sphincter. Results: In all subjects, distal HRIM-BI values correlated weakly with distal MNBI(r = 0.34-0.39, P < 0.005). However, in patients with ILPRS, distal HRIM-BI corelated moderately with distal MNBI(r = 0.43-0.48, P < 0.005). The areas under the receiver operating characteristic curve was 0.78 (P = 0.001) with a sensitivity of 0.83 and a specificity of 0.68. No correlation exists between distal HRIM-BI and distal MNBI in patients with CTRS, and between proximal HRIM-BI and proximal MNBI in both groups. Conclusions Distal HRIM-BI from HRIM may potentially predict pathological MNBI in patients with ILPRS, but not in those with CTRS. Future outcome studies linked to the metric are warranted.

Objectives: . Endotype-based interventions have shown promise in the treatment of patients with obstructive sleep apnea, and upper airway surgery is a key therapeutic option. However, responses to surgery vary among patients with obstructive sleep apnea. This study aims to examine changes in endotypic traits following upper airway surgery and to explore their association with surgical outcomes. Methods: . We prospectively recruited 25 patients with obstructive sleep apnea who visited a single sleep center for upper airway surgery. These patients underwent polysomnographic studies both before and after surgical intervention. During non-rapid eye movement and rapid eye movement sleep, we estimated endotypic traits—including collapsibility (Vpassive), arousal threshold, loop gain, and upper airway compensation—with the phenotyping using polysomnography method. Based on improvements in the apnea-hypopnea index, patients were classified as either responders or non-responders. We compared the preoperative endotypic traits between these groups using Mann-Whitney tests. Additionally, we compared changes in endotypic traits pre- and post-surgery between responders and non-responders using generalized linear mixed models. Results: . We identified 12 responders and 13 non-responders. Compared to non-responders, responders exhibited improved collapsibility during rapid eye movement sleep (22.3 vs. −8.2%eupnea in Vpassive, P=0.01), and their arousal threshold decreased during non-rapid eye movement sleep (−22.4%eupnea, P=0.02). No endotypic trait predicted surgical response; however, the apnea-hypopnea index during rapid eye movement sleep was higher among responders than non-responders (51.8/hr vs. 34.4/hr, P=0.05). Conclusion . Upper airway surgery significantly reduced collapsibility during rapid eye movement sleep in responders. The target pathology for upper airway surgery is a compromised upper airway during rapid eye movement sleep.

Background/Aims: Distal mean nocturnal baseline impedance (MNBI) measuring via pH-impedance may be valuable in diagnosing patients with suspected laryngopharyngeal reflux (LPR). However, its wide adoption is hindered by cost and invasiveness. This study investigates whether baseline impedance measured during high-resolution impedance manometry (HRIM-BI) can predict pathological MNBI. Methods: A cross-sectional study in Taiwan included 74 subjects suspected of LPR, who underwent HRIM (MMS) and pH-impedance testing (Diversatek), after stopping proton pump inhibitors for more than 7 days. Subjects with grade C or D esophagitis or Barrett’s esophagus were excluded. The cohort was divided into 2 groups: those with concomitant typical reflux symptoms (CTRS, n = 28) and those with isolated LPR symptoms (ILPRS, n = 46). HRIM-BI measurements focused on both distal and proximal esophagi. Pathological MNBI was identified as values below 2065 Ω, measured 3 cm above the lower esophageal sphincter. Results: In all subjects, distal HRIM-BI values correlated weakly with distal MNBI(r = 0.34-0.39, P < 0.005). However, in patients with ILPRS, distal HRIM-BI corelated moderately with distal MNBI(r = 0.43-0.48, P < 0.005). The areas under the receiver operating characteristic curve was 0.78 (P = 0.001) with a sensitivity of 0.83 and a specificity of 0.68. No correlation exists between distal HRIM-BI and distal MNBI in patients with CTRS, and between proximal HRIM-BI and proximal MNBI in both groups. Conclusions Distal HRIM-BI from HRIM may potentially predict pathological MNBI in patients with ILPRS, but not in those with CTRS. Future outcome studies linked to the metric are warranted.

Background/Aims: Diagnosis of isolated laryngopharyngeal reflux symptoms (ILPRS), ie, without concomitant typical reflux symptoms (CTRS), remains difficult. Mean nocturnal baseline impedance (MNBI) reflects impaired mucosal integrity. We determined whether esophageal MNBI could predict pathological esophagopharyngeal reflux (pH+) in patients with ILPRS. Methods: In this cross-sectional study conducted in Taiwan, non-erosive or low-grade esophagitis patients with predominant laryngopharyngeal reflux symptoms underwent combined hypopharyngeal multichannel intraluminal impedance-pH monitoring when off acid suppressants. Participants were divided into the ILPRS (n = 94) and CTRS (n = 63) groups. Asymptomatic subjects without esophagitis (n = 25) served as healthy controls. The MNBI values at 3 cm and 5 cm above the lower esophageal sphincter (LES) and the proximal esophagus were measured. Results: Distal but not proximal esophageal median MNBI values were significantly lower in patients with pH+ than in those with pH– (ILPRS in pH+ vs pH–: 1607 Ω vs 2709 Ω and 1885 Ω vs 2563 Ω at 3 cm and 5 cm above LES, respectively; CTRS in pH+ vs pH–: 1476 vs 2307 Ω and 1500 vs 2301 Ω at 3 cm and 5 cm above LES, respectively, P < 0.05 for all). No significant differences of any MNBI exist between any pH– subgroups and healthy controls. The areas under the receiver operating characteristic curve in the ILPRS group were 0.75 and 0.80, compared to the pH– subgroup and healthy controls (P < 0.001 for both), respectively. Interobserver reproducibility was good (Spearman correlation 0.93, P < 0.0001). Conclusion Distal esophageal MNBI predicts pathological reflux in patients with ILPRS.

Background/Aims: Hypopharyngeal multichannel intraluminal impedance-pH (HMII-pH) technology incorporating 2 trans-upper esophageal sphincter impedance channels has been developed to detect pharyngeal reflux. We used the HMII-pH technique to validate the candidate pharyngeal acid reflux (PAR) episodes based on the dual-pH tracings and determined the interobserver reproducibility. Methods: We conducted a cross-sectional study in tertiary centers in Taiwan. Ninety patients with suspected laryngopharyngeal reflux and 28 healthy volunteers underwent HMII-pH test when off acid suppressants. Candidate PAR episodes were characterized by pharyngeal pH drops of at least 2 units and reaching a nadir pH of 5 within 30 seconds during esophageal acidification. Two experts manually independently identified candidate PAR episodes based on the dual-pH tracings. By reviewing the HMII-pH tracings, HMII-pH-proven PAR episodes were subsequently confirmed. The consensus reviews of HMII-pH-proven PAR episodes were considered to be the reference standard diagnosis. The interobserver reproducibility was assessed. Results: A total of 105 candidate PAR episodes were identified. Among them 84 (80.0%; 95% CI, 71.0-87.0%) were HMII-pH-proven PAR episodes (82 in 16 patients and 2 in 1 healthy subject). Patients tended to have more HMII-pH-proven PAR episodes than healthy controls (median and percentile values [25th, 75th, and 95th percentiles]: 0 [0, 0, 3] vs 0 [0, 0, 0], P = 0.067). The concordance rate in diagnosing HMII-pH-proven PAR episodes between 2 independent observers was 92.2%. Conclusion Our preliminary data showed that 80.0% (71.0-87.0%) of the proposed candidate PAR episodes were HMII-pH-proven PAR episodes, among which the interobserver reproducibility was good.