Aeroacoustics of breath sounds in trachea and upper airway

Modeling radon progeny deposition and dose in human airways using CFD: Effects of respiratory patterns and environmental variables.

Human metapneumovirus (hMPV), which can cause severe lower respiratory tract disease and, rarely, extrapulmonary complications, was identified in a 64-year-old immunocompetent man who presented with acute hypoxemia, bronchoscopic evidence of diffuse alveolar hemorrhage (DAH), and clinically diagnosed acute myocarditis. Notably, hMPV was detected by multiplex PCR on a bronchoalveolar lavage (BAL) sample despite an initial negative upper airway evaluation. The patient's condition was severe and required invasive mechanical ventilation and inotropic support. After the viral etiology was identified, empiric steroids were discontinued, the patient recovered, and his left ventricular ejection fraction improved from ~9% to 40% at discharge. This case underscores the fact that during the hMPV season, acute hypoxemia with diffuse opacities should prompt consideration of infectious DAH and that lower-respiratory multiplex PCR (from BAL or deep tracheal aspirate) can identify pathogens when upper airway tests are negative. It also highlights that, in unexplained DAH, empirical immunosuppression should be used cautiously to perform a full infectious evaluation. Furthermore, when myocarditis is suspected, timely hemodynamic assessment and consideration of mechanical circulatory support may influence the outcomes.

Impact of oral cavity geometry on micro-sized aerosol deposition in the upper airway during oral inhalation

Objective:To investigate the therapeutic effect of upper airway surgery on patients with obstructive sleep apnea hypopnea syndrome（OSAHS）, observing changes in their cardiopulmonary function, and comparing the improvement of cardiopulmonary function between patients with different therapeutic effects. Methods:A total of 70 patients with moderate to severe OSAHS admitted to our hospital from July 2021 to February 2024 were selected. All patients underwent nasal cavity expansion surgery combined with palatopharyngeal and/or tongue surgery, and were followed up for 6 months. According to the therapeutic effect, patients were divided into an effective group（AHI reduction ≥ 50% and postoperative AHI<20, n=52） and an ineffective group（n=18）. The Epworth Sleep Scale（ESS） scores before and after surgery were compared to evaluate the surgical effect, and changes in tcardiopulmonary function were detected. Static and dynamic indicators of cardiopulmonary function, sleep apnea hypopnea index（AHI）, blood oxygen saturation（SaO2） were compared before and after surgery. Pearson correlation analysis was used to explore the correlation between changes in body mass index（BMI） and improvement in cardiovascular and pulmonary function indicators. Results:After surgery, RV/TLC） and dynamic cardiopulmonary function indicators（Peak VO2%, Peak O2 Pulse%, AT, Emax/MVV, etc.） showed significant improvement compared to preoperative levels（P<0.01）. The improvement amplitude in the effective group was significantly greater than that in the ineffective group（P<0.05）. Pearson correlation analysis showed that there was no significant correlation between BMI changes and improvement in cardiovascular and pulmonary function indicators（P>0.05）. Conclusion:For OSAHS patients who cannot tolerate or are unwilling to receive non-invasive assisted ventilation, simultaneous multi-plane upper airway surgery is feasible. Even if the objective efficacy is suboptimal, it can improve cardiopulmonary function and has significant clinical application value.

Oral Submucous Fibrosis (OSMF) with temporomandibular joint ankylosis presents significant challenges to airway management due to restricted mouth opening and fibrosis involving the oropharyngeal tissues. The situation becomes more critical in emergency surgeries with a full stomach, where the risk of aspiration further complicates airway planning. This was a case of a 56-year-old female with known OSMF and restricted mouth opening posted for emergency laparotomy due to a faecal fistula formation at the laparoscopic cholecystectomy port site. Given the anticipated difficult airway and full-stomach status, Awake Fibreoptic Intubation (AFOI) was planned and successfully executed. Awake fibreoptic intubation remains the gold standard in managing anticipated difficult airways, especially when complicated by additional risks like upper airway tumours or infections, cervical spine instability, congenital facial abnormalities, previous difficult intubation, and emergency conditions involving a full stomach where aspiration risk is high. This case reinforced its value in ensuring patient safety in emergency surgical scenarios.

Multiphysics modeling of drug aerosol deposition in realistic human upper airway considering soft palate elasticity, temperature, environment and breathing regime

Artificial intelligence in imaging for obstructive sleep apnea: A comprehensive review.

Tracheotomy.

Caudal aberrant turbinate is a relatively common turbinate bone anomaly in brachycephalic breeds with an undetermined etiology. This paper presents a 5-year-old Pug with a history of otitis media and interna, showing left ear discharge and respiratory distress. Radiography and advanced imaging, including computed tomography (CT) and magnetic resonance imaging (MRI), revealed bilateral otitis externa and media, an elongated and thickened soft palate, a narrowed nasopharynx, and caudal extension of bilateral turbinate structures into the nasopharynx. MRI also revealed left otitis interna. Twenty-six days later, the patient developed severe respiratory distress with radiographic signs of an increased caudodorsal lung opacity and gastric dilation, indicative of non-cardiogenic pulmonary edema from a chronic airway obstruction. Surgical treatment involved folded flap palatoplasty and left total ear canal ablation. Despite treatment, the dog expired due to the persistent respiratory distress. This case highlights that a caudal aberrant turbinate can contribute to airflow obstruction in brachycephalic obstructive airway syndrome (BOAS), particularly when compounded by other upper airway anomalies. CT imaging is valuable for identifying nasal structural abnormalities, including aberrant turbinates. Accordingly, an awareness of such anatomical variations is critical for the diagnosis and management of brachycephalic breeds presenting BOAS-related symptoms.

There is a lack of evidence linking oxidative stress to muscle dysfunction and the worsening of obstructive sleep apnea (OSA). Lipofuscin is a permanent intracellular deposit that accumulates with aging or oxidative stress. Its increase in skeletal muscles may lead to limitations in muscle function, such as weakness and fatigue. We aim to investigate whether lipofuscin deposits in the upper airway muscles of patients with severe OSA are increased compared to those in patients with primary snoring or very mild OSA. We studied pharyngeal framework muscle tissue samples from non-obese adults, with one group having severe OSA and another having primary snoring or very mild OSA (snorer group). Lipofuscin was identified by analyzing staining patterns from Sudan Black B and fluorescence microscopy. We compared lipofuscin levels and distribution in the muscle fibers between the groups. Despite presenting similar age and body mass index, patients with severe OSA exhibited markedly larger and more concentrated deposits of lipofuscin in the upper airway muscles, particularly along the borders of the muscle fascicles, compared to the snorer group. Compared to primary snorers, patients with severe OSA accumulate lipofuscin in their pharyngeal muscles. Our findings may provide novel insight into the role of lipofuscin as both a marker and a cause of the aggravation of OSA, in light of a possible lipofuscin-induced progressive myopathy.

Brachycephalic obstructive airway syndrome (BOAS) results from upper airway anatomical abnormalities and may cause systemic effects depending on severity. A prospective, case‒control and observational study was conducted. All dogs underwent a physical examination, BOAS functional grading, and venous and arterial blood sampling for haematological, biochemical, arterial blood gas and acute phase protein (APP) analyses. The hypothesis was that APPs, leukogram parameters and arterial blood gas alterations are associated with BOAS severity. Fifty-two brachycephalic dogs were assigned to BOAS grades 0 (n=14), 1 (n=15), 2 (n=11) and 3 (n=12) and then compared with a mesocephalic group (n=15). BOAS grades 2 and 3 had higher haematocrit (HCT) (p=0.045), and all grades showed elevated leukocyte counts (p=0.005), creatinine (p<0.001), alpha-1-acid glycoprotein (AGP) (p<0.001), haptoglobin (p=0.036) and arterial pressure of carbon dioxide (PaCO2) (p< 0.001) compared to mesocephalic dogs. Total protein (TP) was higher in grades 1-3 (p<0.001), and albumin was lower in all BOAS grades (p<0.001). Lactate was elevated in grade 0 and controls (p=0.006). Multivariate analysis identified haemoglobin, HCT, TP, AGP, PaCO2, base excess and bicarbonate as the variables most strongly associated with BOAS severity. Age and weight selection criteria may have influenced BOAS scores and inflammatory markers. BOAS grades were associated with hypoventilation, increased HCT and significant differences in inflammatory markers within physiological ranges, suggesting early systemic changes beyond respiratory dysfunction.

Obstructive sleep apnoea (OSA) is a common, chronic respiratory disorder associated with major co-morbidity and adverse safety consequences. New research has highlighted the heterogeneity of OSA pathogenesis and the importance of non-anatomical contributors beyond the primary cause-impaired pharyngeal anatomy. For > 40 years, continuous positive airway pressure (CPAP), which works downstream from the causes of OSA, has been the mainstay therapeutic approach. While efficacious when used, CPAP is associated with poor tolerance and acceptance which limits real-world clinical effectiveness. Non-CPAP therapies that target the primary anatomical cause such as oral appliances and upper airway surgery, reduce OSA severity by ~ 50%. Given that obesity increases the anatomical predisposition for OSA, new weight loss drugs can reduce OSA severity in the ~ 50% of patients who are obese. Thus, although these therapies can resolve OSA for certain patients, overall efficiency varies and is challenging to predict with currently available clinical tools. Recent translation of OSA pathogenesis research has unlocked new pharmacotherapy targets beyond impaired pharyngeal anatomy. These include drugs to activate the pharyngeal dilator muscles, reduce unstable respiratory control and promote deeper, more stable sleep and breathing. Accordingly, the sleep medicine field is undergoing a paradigm shift as OSA pharmacotherapy becomes a reality. This article outlines the latest OSA pathophysiology knowledge and accompanying recent major developments in OSA pharmacotherapy. Practical, readily available, clinical tools for OSA endotyping to help move beyond the current problematic one-size-fits-all, trial-and-error treatment model towards a targeted paradigm tailored to underlying mechanisms that include emerging pharmacotherapy are also included.

Background: Obstructive sleep apnea (OSA) is characterized by repeated episodes of complete or partial upper airway obstruction during sleep. This sleep disorder is often ignored or undiagnosed because it is often underdiagnosed due to non-specific symptoms, even though it can cause health problems and interfere with the quality of life. The gold standard for diagnosing OSA is polysomnography (PSG), but PSG is not available in all healthcare facilities. The Friedman Tongue Position (FTP) examination is a simple method for estimating upper airway obstruction and is expected to serve as a screening tool for OSA risk.Objective: To determine the association between Friedman Tongue Position and the Respiratory Disturbance Index (RDI) in obstructive sleep apnea. To determine the association between body mass index, age, and sex with the respiratory disturbance index in obstructive sleep apnea.Methods: The study was conducted from August to October 2024 at Dr. Kariadi Central General Hospital Semarang, with a total sample of 44 adults (&gt;18 years), comprising 22 OSA and 22 non-OSA subjects. This was a cross-sectional study involving patients who had undergone PSG. The RDI values were obtained from PSG results. FTP was assessed through tongue examination. Data were analyzed using the Chi-square test.Results: Chi-square analysis revealed significant associations between BMI (p = 0.013) and FTP (p &lt; 0.001) and RDI. Meanwhile, Fisher’s Exact test for age (p=0.697) and Chi-square test for sex (p=0.203) indicated no significant association with RDI.Conclusion: FTP and BMI showed significant associations with RDI, where higher FTP grades and obesity increased the likelihood of OSA. In contrast, age and sex were not significantly associated with RDI, indicating that they do not independently influence respiratory disturbance severity.

Background: Necrotizing fasciitis (NF) of the head and neck is a rare but rapidly progressive and life-threatening soft tissue infection that constitutes a true surgical emergency. Due to the complex anatomy of the cervicofacial region and the proximity to the upper airway, early diagnosis and management are particularly challenging, and delayed recognition is associated with high morbidity and mortality. This article aims to provide a concise and clinically oriented overview of the presentation, diagnostic pitfalls, and current management strategies for cervicofacial necrotizing fasciitis.Methods: A narrative review of the available literature was conducted and complemented by clinical experience from a tertiary referral center. Key aspects including etiology, risk factors, clinical features, imaging findings, laboratory parameters, microbiology, surgical management, airway control, and adjunctive therapies were synthesized and critically discussed.Results: Cervicofacial NF often presents with disproportionate pain, rapidly progressive swelling, and early systemic toxicity. Odontogenic infections represent the most common source, frequently in the presence of systemic comorbidities such as diabetes mellitus or immunosuppression. Contrast-enhanced computed tomography is the imaging modality of choice, whereas laboratory scoring systems such as the LRINEC score show limited sensitivity in head and neck infections. The cornerstone of treatment is immediate and aggressive surgical debridement combined with broad-spectrum intravenous antibiotics, early airway protection, and intensive care support. Repeated surgical interventions are frequently required. The role of adjunctive hyperbaric oxygen therapy remains controversial and cannot be routinely recommended based on current evidence.Conclusion: Necrotizing fasciitis of the head and neck requires a high index of suspicion, prompt imaging, and decisive multidisciplinary management. Early surgical intervention and airway control are critical determinants of outcome. Given the rarity of cervicofacial NF, further multicenter studies and registries are needed to refine diagnostic tools, identify prognostic factors, and optimize treatment strategies, particularly in high-risk populations such as immunocompromised and oncologic patients.

Viral infections of the upper airways are common in children and adolescents, often presenting with mild symptoms and typically resolving without the need for hospitalization. Epstein-Barr virus (EBV), a gammaherpesvirus, can cause diverse clinical syndromes and transient immune dysregulation, potentially predisposing to bacterial superinfection. We report a 13-year-old girl with critical upper airway obstruction due to necrotizing ulcerative oropharyngitis in the context of an EBV infection, with superinfection by Prevotella oris and methicillin-sensitive Staphylococcus aureus (MSSA) isolated from operative tissue specimens. Within a very short time, the patient developed EBV-associated nephritis and pneumonia, severe sepsis, and acute respiratory distress syndrome (ARDS). Extensive soft-tissue necrosis precipitated life-threatening hemorrhage from the right external carotid artery followed by a second hemorrhage on the left, requiring coil embolization and ligation. Additionally, the patient experienced neurological complications due to thiamine deficiency, contributing to a complex and prolonged recovery process. Despite the severity of her illness, multidisciplinary management enabled stabilization and eventually discharge to a rehabilitation facility. To our knowledge, fulminant necrotizing oropharyngitis with bilateral external carotid hemorrhage during acute EBV infection in an immunocompetent adolescent is exceedingly rare. This highlights the importance of considering anaerobic oral colonizers as potential pathogens in maxillofacial infections. Clinicians should reassess for bacterial superinfection when EBV courses are protracted or deteriorating.

Forestier’s disease, or diffuse idiopathic spinal hyperostosis, can exceptionally lead to acute obstruction of the upper airways when the hyperostosis is located in the cervical region. We report the case of an 87-year-old man admitted for acute inspiratory dyspnoea and progressive dysphonia. Endoscopic examination confirmed left laryngeal paralysis and pharyngolaryngeal oedema. Imaging revealed a large anterior hyperostosis compressing the airway. This case illustrates the interaction between mechanical compression, local inflammation, and chronic laryngeal paralysis, which can lead to severe dyspnoea. Early recognition and appropriate imaging allow for rapid and effective management.

Background: Obstructive sleep apnea (OSA) is a heterogeneous disorder traditionally classified and stratified by the apnea–hypopnea index (AHI), which fails to capture variability in symptom burden, comorbid associations, and treatment responses. Clinical phenotyping has emerged as a promising strategy to improve disease characterization and management over the last decade. Methods: We conducted a narrative literature review of studies published between January 2014 and December 2022 that used cluster analysis to define OSA phenotypes in adults with moderate-to-severe disease (AHI ≥ 15 events/h). Eligible studies employed validated questionnaires, symptom reporting, and comorbidity profiling to identify subgroups. Findings were summarized across diverse populations, with emphasis on phenotype reproducibility, comorbidity associations, and treatment implications. Results: Across international cohorts, three reproducible symptom-based phenotypes were consistently identified: excessively sleepy (ES), disturbed sleep (DS), and minimally symptomatic (MS). Additional subtypes, such as upper airway dominant (UA) and moderately sleepy (MoS), were described in larger cohorts. Phenotypes differed in demographic profiles, comorbidity burden, and treatment adherence. ES patients exhibited the greatest symptom burden, higher cardiovascular risk, and better adherence to positive airway pressure (PAP) therapy, with significant symptomatic improvement. DS patients frequently reported insomnia symptoms, showed modest PAP-related gains, and may benefit from adjunctive insomnia-targeted interventions. MS patients, despite low symptom burden, often carried substantial comorbidity risk, specifically buildup of OSA-related cardiovascular risk. Conclusions: Symptom-based OSA phenotypes are reproducible across diverse populations and provide clinically meaningful insights beyond AHI. They allow for improved risk stratification, highlight gaps in detection of minimally symptomatic patients, and inform personalized treatment strategies. Integrating phenotyping into clinical practice has the potential to enhance diagnostic accuracy, optimize therapeutic outcomes, and refine cardiovascular risk prediction in OSA.

Allergic rhinitis (AR) is an inflammatory disease of the upper airway that primarily affects the nasal mucosa, with Th2 differentiation-driven inflammation as a key contributor. A bioinformatics analysis of dataset GSE52804 identified Six-transmembrane epithelial antigen of prostate 4 (STEAP4), a metalloreductase involved in inflammation regulation, as associated with AR progression, though its specific function remains unclear. Data obtained from nasal mucosal tissues from AR patients (n = 13) and an ovalbumin (OVA)-induced AR mouse model demonstrated a marked upregulation of STEAP4. Subsequent loss-of-function experiments revealed that STEAP4 knockdown reduced Th1/Th2 imbalance-mediated inflammation, alleviating allergic symptoms in OVA-treated mice. Further investigations involved the purification of naïve CD4+ T cells from healthy murine splenocytes and their Th2 polarization. Consistently, STEAP4 knockdown inhibited Th2 differentiation and the production of Th2-related cytokines in vitro. Additionally, Guanine adenine thymine adenine sequence-binding protein 3 (GATA3), a transcription factor essential for Th2 differentiation, was predicted to bind to the STEAP4 promoter. CHIP-PCR and dual-luciferase assays confirmed the transcriptional regulation of STEAP4 by GATA3. More importantly, STEAP4 knockdown rescued the promoting effects of GATA3 overexpression on Th2 differentiation. In conclusion, STEAP4 functions downstream of GATA3 to promote AR development by promoting Th2 differentiation-mediated inflammation, suggesting its potential as a target for AR treatment.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10753-025-02381-7.

This study assessed 2-year oropharyngeal airway changes in skeletal Class II patients following isolated mandibular advancement by bilateral sagittal split osteotomy (BSSO) with or without maxillary setback by Le Fort I osteotomy (Le fort I). Cone-beam computed tomography (CBCT) data from 25 isolated BSSO and 57 BSSO + Le fort I patients were retrospectively analyzed at three stages: preoperatively (T0), 3 months (T1), and 2 years postoperatively (T2). The total upper airway volume (V), minimum cross-sectional area (CSAmin), and volumes of the nasopharynx (VNA), velopharynx (VVE), and glossopharynx (VGL) were measured via Dolphin Imaging. Isolated BSSO significantly increased V, CSAmin, VNA, VVE, and VGL by 38.86%, 69.49%, 22.31%, 46.05%, and 46.94%, respectively, at T1 (P < 0.01) and 21.85%, 43.11%, 13.85%, 19.73%, and 25.38%, respectively, at T2 (P < 0.05). From T1 to T2, V, CSAmin, VVE, and VGL decreased by 12.24%, 15.56%, 18.02%, and 14.67%, respectively (P < 0.05). Multivariate regression revealed that each 1mm advancement of the PNS and B points increased V by 1038mm³ and VVE by 519mm³; PNS advancement increased VNA by 708mm³ (P < 0.05). Compared with BSSO + Le fort I, isolated BSSO yielded greater short-term improvements (V: +11175 vs. +3638mm³; P < 0.001) and superior long-term stability in V and VNA (P < 0.05). Notably, the combined advancement of PNS and B point may be a robust predictor for postoperative changes of the upper airway volume. Isolated BSSO induces sustained upper airway expansion for 2 years, which is driven primarily by hard tissue advancements. Compared with BSSO + Le fort I, this technique has superior short- and long-term efficacy, providing guidance for the optimized management of skeletal Class II patients. This study was approved by the Ethics Committee of Peking University Stomatological Hospital (Approval No. PKUSSIRB-202167121).