Swallowing biomechanics in tracheostomised critically ill patients compared to age- and gender-matched healthy controls.

Objective: The mechanistic effects of a tracheostomy on swallowing are unclear. Pharyngeal high-resolution manometry with impedance (P-HRM-I) is a novel swallow assessment tool providing quantifiable metrics. This study aimed to characterise swallowing biomechanics in tracheostomised critically ill (non-neurological) patients. Design: Cohort study. Setting: Australian tertiary hospital intensive care unit. Participants: Tracheostomised adults, planned for decannulation. Main outcome measures: Swallowing assessment using P-HRM-I, compared to healthy age- and gender-matched controls. Results: In this tracheostomised cohort (n = 10), the Swallow Risk Index, a global measure of swallow function, was significantly elevated (p < 0.001). At the upper oesophageal sphincter (UOS), hypopharyngeal intrabolus pressure and UOS integrated relaxation pressure were significantly elevated (control 0.65 mmHg [-1.02, 2.33] v tracheostomy 13.7 mmHg [10.4, 16.9], P < 0.001; control -4.28 mmHg [-5.87, 2.69] v tracheostomy 12.2 mmHg [8.83, 15.6], P < 0.001, respectively). Furthermore, UOS opening extent and relaxation time were reduced (control 4.83 mS [4.60, 5.07] v tracheostomy 4.33 mS [3.97, 4.69], P = 0.002; control 0.52 s [0.49, 0.55] v tracheostomy 0.41 s [0.37, 0.45], P < 0.001, respectively). Total pharyngeal contractility (PhCI) measuring pharyngeal pressure generation was significantly elevated (control 199.5 mmHg cm.s [177.4, 221.6] v tracheostomy 326.5 mmHg cm.s [253.3, 399.7]; P = 0.001). Conclusion: In a critically ill tracheostomised cohort, UOS dysfunction was the prevalent biomechanical feature, with elevated pharyngeal pressures. Pharyngeal weakness is not contributing to dysphagia in this cohort. Instead, elevated pharyngeal pressures may represent a compensatory mechanism to overcome the UOS dysfunction. Further studies to extend these findings may inform the development of timely and targeted rehabilitation.

Pharyngeal tongue base augmentation for dysphagia therapy: A prospective case series in patients post head and neck cancer treatment.

BACKGROUND: Dysphagia post head and neck cancer (HNC) multimodality treatment is attributed to reduced pharyngeal strength. We hypothesized that pharyngeal tongue base augmentation for dysphagia (PAD therapy) would increase pharyngeal pressures during swallowing thereby improving swallow symptoms. METHODS: Adults with moderate-severe dysphagia post-HNC treatment had PAD therapy using a temporary filler (hyaluronic acid [HA]), with follow-up long-lasting lipofilling. Swallowing preprocedure and postprocedure was assessed with the Sydney Swallow Questionnaire (SSQ), High-Resolution Pharyngeal Manometry (HRPM), and Videofluoroscopic Swallowing Study (VFSS). Statistical comparison utilized paired tests. RESULTS: Six participants (all male; median age 64 years [IQR 56, 71]) underwent PAD therapy at a median of 47 [IQR 8, 95] months post-treatment. SSQ scores reduced from baseline (mean 1069 [95%CI 703, 1434]) to post-HA (mean 579 [76, 1081], p > 0.05), and post-lipofilling (491 [95%CI 913, 789], p = 0.003, n = 4). Individual participants demonstrated reduced Swallow Risk Index, Bolus Presence Time, and increased Upper Esophageal Sphincter opening, but mesopharyngeal contractile pressures were unchanged. VFSS measures of aspiration, residue, and severity were unchanged. CONCLUSIONS: Novel PAD therapy is safe and improves dysphagia symptoms. Biomechanical swallowing changes are suggestive of more efficacious bolus propulsion with conservative filler volume, but this was unable to resolve residue or aspiration measures.

Swallowing biomechanics before and following multi-level upper airway surgery for obstructive sleep apnea.

STUDY OBJECTIVES: The effect of contemporary multi-level upper airway surgery for obstructive sleep apnea on swallowing is unclear. This study assessed the biomechanical swallowing function in participants with obstructive sleep apnea pre- and post-modified uvulopalatopharyngoplasty and coblation channeling of the tongue. METHODS: In this prospective, longitudinal study, adults diagnosed with moderate-severe obstructive sleep apnea who underwent modified uvulopalatopharyngoplasty and coblation channeling of the tongue surgery had swallowing biomechanics assessed using high-resolution pharyngeal manometry and analyzed with swallowgateway.com. Symptomatic swallowing difficulty was evaluated using the Sydney Swallow Questionnaire (≥ 234). General linear mixed-model analysis was conducted to evaluate the difference pre- and post-modified uvulopalatopharyngoplasty and coblation channeling of the tongue. Data are presented as mean [95% confidence intervals]. RESULTS: High-resolution pharyngeal manometry assessments were conducted in 10 participants (7 men; median age 50 [interquartile range 36-65]) preoperatively and repeated postoperatively at 9 months [interquartile range 6-13]. Self-reported dysphagia was unchanged following surgery (Sydney Swallow Questionnaire =149 [53, 447] to 168 [54, 247]; P = .093). High-resolution pharyngeal manometry outcomes indicated reduced mesopharyngeal pressures (148 [135, 161] to 124 [112, 137] mm Hg s cm; P = .011), reduced hypopharyngeal pressures (113 [101, 125] to 93 [84, 102] mm Hg s cm; P = 0.011), and reduced upper esophageal sphincter relaxation pressure (5 [4, 6] to 2 [1,3] mm Hg; P = 0.001) but no change to velopharyngeal pressures (135 [123, 147] to 137 [117, 157] mm Hg s cm; P = .850) postsurgery. CONCLUSIONS: Modified uvulopalatopharyngoplasty may have less implications on the swallow mechanism than previously suspected. In contrast, the reduction in mesopharyngeal contractile pressures associated with coblation channeling of the tongue, although within normal limits, may affect bolus propulsion. Biomechanical alterations were insufficient to worsen self-reported swallowing function. CITATION: Schar MS, Omari TI, Woods CW, et al. Swallowing biomechanics before and following multi-level upper airway surgery for obstructive sleep apnea. J Clin Sleep Med. 2022;18(4):1167-1176.

Altered swallowing biomechanics in people with moderate-severe obstructive sleep apnea.

STUDY OBJECTIVES: Dysphagia is a common but under-recognized complication of obstructive sleep apnea (OSA). However, the mechanisms remain poorly described. Accordingly, the aim of this study was to assess swallowing symptoms and use high-resolution pharyngeal manometry to quantify swallowing biomechanics in patients with moderate-severe OSA. METHODS: Nineteen adults (4 female; mean (range) age, 46 ± 26-68 years) with moderate-severe OSA underwent high-resolution pharyngeal manometry testing with 5-, 10-, and 20-mL volumes of thin and extremely thick liquids. Data were compared with 19 age- and sex-matched healthy controls (mean (range) age, 46 ± 27-68 years). Symptomatic dysphagia was assessed using the Sydney Swallow Questionnaire. Swallow metrics were analyzed using the online application swallowgateway.com. General linear mixed model analysis was performed to investigate potential differences between people with moderate-severe OSA and controls. Data presented are means [95% confidence intervals]. RESULTS: Twenty-six percent (5 of 19) of the OSA group but none of the controls reported symptomatic dysphagia (Sydney Swallow Questionnaire > 234). Compared with healthy controls, the OSA group had increased upper esophageal sphincter relaxation pressure (-2 [-1] vs 2 [1] mm Hg, F = 32.1, P < .0001), reduced upper esophageal sphincter opening (6 vs 5 mS, F = 23.6, P < .0001), and increased hypopharyngeal intrabolus pressure (2 [1] vs 7 [1] mm Hg, F = 19.0, P < .05). Additionally, upper pharyngeal pressures were higher, particularly at the velopharynx (88 [12] vs 144 [12] mm Hg⋅cm⋅s, F = 69.6, P < .0001). CONCLUSIONS: High-resolution pharyngeal manometry identified altered swallowing biomechanics in people with moderate-severe OSA, which is consistent with a subclinical presentation. Potential contributing mechanisms include upper esophageal sphincter dysfunction with associated upstream changes of increased hypopharyngeal distension pressure and velopharyngeal contractility. CITATION: Schar MS, Omari TI, Woods CM, et al. Altered swallowing biomechanics in people with moderate-severe obstructive sleep apnea. J Clin Sleep Med. 2021;17(9):1793-1803.