Bronchial collapse and bronchial stenting in 9 dogs

BACKGROUND

Principal and lobar bronchial collapse is increasingly recognized as an isolated entity.

OBJECTIVE

Retrospectively describe the procedure and outcomes of dogs undergoing bronchial stenting at a single referral hospital.

ANIMALS

Nine client-owned dogs with variable degrees of collapse of the left principal bronchus (LPB), lobar bronchus 1 (LB1), and lobar bronchus 2 (LB2), and with clinically relevant signs of respiratory dysfunction.

METHODS

Data were collected from patient records. All dogs underwent stenting of the LPB and LB2. Anatomic and functional impairment grades were assigned to each case before and 4 weeks after stenting. Data regarding response to stenting and complications were evaluated.

RESULTS

Bronchial stenting was considered successful in all cases, with all dogs experiencing improved quality of life (QOL), and decreased functional impairment grade at 4 weeks post-stenting. Follow-up of >6 months was available for 6 dogs and of these, 5 were alive at 12 months, 3 were alive at 18 months, and 1 was alive at 24 months. Stent-related complications occurred in 4 dogs, and were resolvable in 3. Two dogs developed pneumothorax, 1 developed recurrent pneumonia, and 1 developed new-onset coughing. All dogs had mild and manageable coughing post-stenting.

CONCLUSIONS AND CLINICAL IMPORTANCE

Stenting of the LBP and LB2 might be an effective option for dogs with advanced collapse of these bronchi and associated signs. Although all included dogs had resolution or improvement of clinical signs considered life-threatening or as affecting QOL, ongoing coughing is expected. Patient selection appears important with regard to achieving successful outcomes.

Comparison of Four Mechanical Insufflation-Exsufflation Devices: Effect of Simulated Airway Collapse on Cough Peak Flow

BACKGROUND

Mechanical insufflation-exsufflation (MI-E) devices are used to improve airway clearance in individuals with acute respiratory failure. Some MI-E devices measure cough peak flow (CPF) during MI-E to optimize pressure adjustments. The aim was to compare CPF and effective cough volume (ECV: volume expired/coughed > 3 L/s) measurements between 4 MI-E devices under simulated conditions of stable versus collapsed airway.

METHODS

Four MI-E devices were tested on the bench. Each device was connected via a standard circuit to a collapsible tube placed in an airtight chamber that was attached to a lung model with adjustable compliance and resistance. Pressure was measured upstream and downstream the collapsing tube; air flow was measured between the chamber and the lung model. Each device was tested in 2 conditions: collapse condition (0 cm H2O) and no-collapse condition (-70 cm H2O). For each condition, 6 combinations of inspiratory/expiratory pressures were applied. CPF was measured at the "mouth level" by the device built-in flow meter and at the "tracheal level" by a dedicated pneumotachograph. Comparisons were performed with non-parametric tests.

RESULTS

CPF values measured at the tracheal level and ECV values differed between devices for each inspiratory/expiratory pressure in the collapse and no-collapse conditions (P < .001). CPF values were significantly lower at the tracheal level in the collapse as compared with the no-collapse condition (P < .001 for each device), whereas they were higher at the mouth level (P < .05) for 3 of the 4 devices.

CONCLUSIONS

CPF values differed significantly across MI-E devices, highlighting limitation(s) of using only CPF values to determine cough effectiveness. In simulated of airway collapse, CPF increased at the mouth, whereas it decreased at the tracheal level.

The evolution of anesthesia management of patients with anterior mediastinal mass

Anesthesia management of patients with mediastinal mass compressing the central airway is considered challenging. It is widely believed that general anesthesia induction in patients with mediastinal mass is associated with airway collapse, difficulty in ventilation and hemodynamic compromise. Additionally, several case reports and case series described patients demise after induction of general anesthesia. This has led to the strong recommendations to use inhalation induction, avoid the use of muscle relaxant and maintenance of spontaneous ventilation. Recent studies shed new light on our understanding of airway changes associated with mediastinal mass by directly visualizing and measuring the actual changes of the airway caliber and the variation in the peak inspiratory flow (PIF) and peak expiratory flow (PEF) in patients with mediastinal mass. These studies describe the changes in airway mechanics in different states e.g., awake and anesthetized, spontaneous and positive pressure ventilated with or without muscle relaxation. Interesting new findings in these recent publications show that general anesthesia with and without muscle relaxation does not worsen a pre-existing narrowing of the airway compressed by mediastinal mass. Moreover, it was discovered that the addition of positive pressure ventilation, positive end-expiratory pressure (PEEP) and muscle relaxation in an anesthetized patient were associated with improvement in the airway caliber and airflow in these patient's population. This new understanding of the mechanics of airway obstruction and the effects of anesthesia and mechanical ventilation on patients with mediastinal mass challenges our current anesthesia practices and leads us to consider a new approach to anesthetize and ventilate these patients. This article will review the past literature that led to the widely practiced current anesthesia techniques and how it is challenged with the new research. The author will also provide a new perspective and anesthesia technique that align with the new research findings for safe induction and maintenance of general anesthesia in patients with mediastinal mass.

Stents in Veterinary Medicine

Stenting in veterinary medicine has been a rapidly growing method of interventional surgery for several years. This procedure is usually performed in the respiratory and urinary tracts, but there are cases of stenting of blood vessels or gastrointestinal structures. It is based on maintaining the permeability of a given tubular structure, thus allowing the passage of gas or liquid. This procedure is often performed as a first-line treatment in situations where pharmacological agents do not work and as an alternative method, often cheaper than the classically performed ones. There are also cases where stenting is used as a palliative treatment, e.g., to enable defecation in colonic obstruction due to tumour infiltration of the colon wall. Stenting is often a life-saving or comfort-improving procedure for animals, but one should also be aware of possible postoperative complications and be prepared for any adversity. For this reason, this review provides an insight into the current knowledge in veterinary medicine about stenting and the consequences associated with this procedure.

Nasopharyngeal luminal change on cervical radiography in brachycephalic dogs without respiratory signs

This study aimed to prospectively assess nasopharyngeal luminal changes in brachycephalic dogs without respiratory signs using cervical radiography. Forty brachycephalic dogs without cardiopulmonary diseases were included. The nasopharyngeal luminal change was calculated on inspiratory and expiratory cervical lateral radiographs. The median nasopharyngeal luminal change was 21.6% (range, 0.3-85.6%). In five dogs, a nasopharyngeal luminal change of >50% was identified. There was no correlation between nasopharyngeal luminal changes and age, sex, body weight, or body condition score. These results suggest that brachycephalic dogs without cardiopulmonary diseases may be over-diagnosed with partial pharyngeal collapse. Further studies comparing nasopharyngeal luminal changes between clinically healthy brachycephalic dogs and dogs with respiratory signs are warranted.

Coordination of Care for Expiratory Central Airway Collapse: A Structured Process for a Multifaceted Disease

Common respiratory symptoms, including dyspnea, cough, sputum production, and recurrent infections, frequently remain without a clear cause and may be the result of expiratory central airway collapse (ECAC). Establishing the diagnosis and appropriate treatment plan for patients with ECAC is challenging and benefits from a multidisciplinary approach. A coordinator role is crucial in this process to ensure optimal patient-centered outcomes. We describe the coordination of care in the process of diagnosing and treating ECAC. The coordinator leads the organization of the multiple services involved in the care of patients with ECAC, including pulmonary medicine, interventional pulmonology, radiology, and thoracic surgery, as well as hospital inpatient staff. From initial screening to evaluation and management with airway stents and corrective treatment with tracheobronchoplasty, the ECAC coordinator oversees the entire process of care for patients with ECAC.

Nasopharyngeal collapse can be identified on radiography in healthy male Beagle dogs without cardiopulmonary diseases

Pharyngeal collapse has been described as a decrease of more than 50% in the diameter of the lumen. However, there has been no study on changes in the pharyngeal lumen in clinically normal dogs. The hypothesis of this prospective, observational, and pilot study was that change in nasopharyngeal lumen would be over 50% in Beagle dogs without cardiopulmonary diseases. Thus, we assessed the nasopharyngeal luminal change using cervical radiography in Beagle dogs without respiratory signs or cardiac abnormalities. The study sample included 42 Beagle dogs without cardiopulmonary diseases. Cervical radiographies were acquired during inspiration and expiration, and nasopharyngeal luminal change (%) was calculated. The median nasopharyngeal luminal change was 16.6%, and nasopharyngeal luminal change over 50% was identified in two dogs. The nasopharyngeal luminal change was significantly associated with body condition score and body weight. There was no correlation between nasopharyngeal luminal change and age. This study revealed that change in nasopharyngeal lumen over 50% can be identified in Beagle dogs without cardiopulmonary diseases and may be over-diagnosed as partial pharyngeal collapse. Further studies for comparing change in nasopharyngeal lumen between clinically normal dogs and dogs with respiratory signs are warranted.

Cinematic CT as a valuable protocol for severe ECAC

Expiratory central airway collapse (ECAC) is a pathology gaining recognition in the medical community due to its unspecific symptoms and diagnostic challenges. Its current gold standard for diagnosis, dynamic bronchoscopy, is invasive. Current non-invasive techniques such as computed tomography (CT) protocols have shown limited reproducibility. We present a case of a 77-year-old man with suspected ECAC who underwent evaluation with two different expiratory CT protocols. The initial standard end-expiratory CT could not detect airway collapsibility. However, dynamic bronchoscopy detected severe ECAC. Afterwards, we implemented a novel CT protocol, called dynamic forced expiratory CT (cinematic), comprising detailed, consecutive helical imaging of the central airway throughout the entire respiratory cycle, detecting severe ECAC, as proven by the earlier dynamic bronchoscopy. We hypothesize this may reduce the risks and need for performing multiple invasive procedures such as dynamic bronchoscopy. Extensive studies are required to evaluate the feasibility of its implementation for diagnosing ECAC.

Oral Positive Expiratory Pressure Device for Excessive Dynamic Airway Collapse Caused by Emphysema

Excessive dynamic airway collapse (EDAC) contributes to breathlessness and reduced quality of life in individuals with emphysema. We tested a novel, portable, oral positive expiratory pressure (o-PEP) device in a patient with emphysema and EDAC. MRI revealed expiratory tracheal narrowing to 80 mm² that increased to 170 mm² with the o-PEP device. After 2-weeks use of the o-PEP device for 33% to 66% of activities, breathlessness, quality of life, and exertional dyspnea improved compared with minimal clinically important differences (MCID): University of California-San Diego Shortness of Breath questionnaire score declined 69 to 42 (MCID, ≥5), St. George's Respiratory Questionnaire score decreased 71 to 27 (MCID, ≥4), and before and after the 6-minute walk test Borg score difference improved from Δ3 to Δ2 (MCID, ≥1). During the 6-minute walk test on room air without the use of the o-PEP device, oxyhemoglobin saturation declined 91% to 83%; whereas, with the o-PEP device, the nadir was 90%. Use of the o-PEP device reduced expiratory central airway collapse and improved dyspnea, quality of life, and exertional desaturation in a patient with EDAC and emphysema.

Experience with bioresorbable splints for treatment of airway collapse in a pediatric population

Objective

To report our experience with novel external tracheal and bronchial placed bioresorbable splints in children with severe symptomatic airway collapse.

Methods

Retrospective review of patients undergoing bioresorbable splint placement.

Results

Between July 2018 and February 2020, 14 patients received 16 external splints (trachea, n = 8; left bronchus, n = 7; and right bronchus, n = 1). Preoperatively, 7 patients had a tracheostomy; 6 of them were receiving mechanical ventilation with ventilator settings so high that they required an inpatient setting, often in an intensive care unit. Median age at implant was 14.5 months (range, 2 months-14 years). Splints were formed from moldable bioresorbable plates (RapidSorb; Synthes, Oberdorf, Switzerland) and were customized intraoperatively around a Hegar dilator. A series of Prolene sutures were placed through into the airway cartilage under simultaneous bronchoscopic and direct visualization and then tied securing the airway within the splint. Concomitant procedures were also performed in the region of the airway splints, consisting of airway reconstruction, cardiovascular procedures, and/or esophageal rotation (related to posterior tracheopexy). Median follow-up was 20 months (interquartile range, 12-21 months). Four patients required no further intervention. Although not necessarily in the splinted region, 7 patients required additional procedures, including posterior tracheobronchopexy (n = 2), temporary tracheal stent placement (n = 1), tracheal resection with end-to-end anastomosis (n = 1), closure tracheostomy (n = 1), and tracheostomy placement (n = 2). One patient required splint replacement and in 1 patient, the splint was removed later. All patients (except 2 deaths from unrelated causes) were discharged home. Three patients required mechanical ventilation at lower settings that allowed home ventilation (1 of those only at night), and 4 patients required tracheostomy collar. Indications for tracheostomy included subglottic stenosis, vocal cord paralysis, pulmonary insufficiency, small airway malacia, and laryngomalacia.

Conclusions

An external bioresorbable splint can provide temporary external support while allowing the age-proportional growth of the airway. We applied readily available bioresorbable plates that were custom-molded based on the location, shape, and length of the collapsing airway in selected patients presenting with severe tracheobronchomalacia from loss of structural support and/or cartilage deformation. Further study that includes long-term outcomes are necessary to define the best role for these external splints as part of comprehensive airway management.

Smart polymer implants as an emerging technology for treating airway collapse in obstructive sleep apnea: a pilot (proof of concept) study

STUDY OBJECTIVES

To assess the use of a novel magnetic polymer implant in reversing airway collapse and identify potential anatomical targets for airway implant surgery in an in vivo porcine model.

METHODS

Target sites of airway collapse were genioglossus muscle, hyoid bone, and middle constrictor muscle. Magnetic polymer implants were sutured to these sites, and external magnetic forces, through magnets with pull forces rated at 102 kg and 294 kg, were applied at the skin. The resultant airway movement was assessed via nasendoscopy. Pharyngeal plexus branches to the middle constrictor muscle were stimulated at 0.5 mA, 1.0 mA, and 2.0 mA and airway movement assessed via nasendoscopy.

RESULTS

At the genioglossus muscles, large magnetic forces were required to produce airway movement. At the hyoid bone, anterior movement of the airway was noted when using a 294 kg rated magnet. At the middle constrictor muscle, an anterolateral (or rotatory) pattern of airway movement was noted when using the same magnet. Stimulation of pharyngeal plexus branches to the middle constrictor revealed contraction and increasing rigidity of the lateral walls of the airway as stimulation amplitude increased. The resultant effect was prevention of collapse as opposed to typical airway dilation, a previously unidentified pattern of airway movement.

CONCLUSIONS

Surgically implanted smart polymers are an emerging technology showing promise in the treatment of airway collapse in obstructive sleep apnea. Future research should investigate their biomechanical role as an adjunct to treatment of airway collapse through nerve stimulation.

The dynamic collapse of the trachea during anesthesia for a pediatric patient with a large anterior mediastinal mass: A case report

Anesthesia for patient with large anterior mediastinal mass might induce life-threatening complication. Maintaining the spontaneous breathing throughout the procedure and finding rescue position are the cornerstones of anesthetic management.

Numerical and Experimental Analysis of Inhalation Airflow Dynamics in a Human Pharyngeal Airway

This paper presents a computational and experimental study of steady inhalation in a realistic human pharyngeal airway model. To investigate the intricate fluid dynamics inside the pharyngeal airway, the numerical predicted flow patterns are compared with in vitro measurements using Particle Image Velocimetry (PIV) approach. A structured mesh with 1.4 million cells is used with a laminar constant flow rate of 10 L/min. PIV measurements are taken in three sagittal planes which showed flow acceleration after the pharynx bend with high velocities in the posterior pharyngeal wall. Computed velocity profiles are compared with the measurements which showed generally good agreements with over-predicted velocity distributions on the anterior wall side. Secondary flow patterns on cross-sectional slices in the transverse plane revealed vortices posterior of pharynx and a pair of secondary flow vortexes due to the abrupt cross-sectional area increase. Finally, pressure and flow resistance analysis demonstrate that greatest pressure occurs in the superior half of the airway and maximum in-plane pressure variation is observed at the velo-oropharynx junction, which expects to induce a high tendency of airway collapse during inhalation. This study provides insights of the complex fluid dynamics in human pharyngeal airway and can contribute to a reliable approach to assess the probability of flow-induced airway collapse and improve the treatment of obstructive sleep apnea.

The prevalence of dynamic pharyngeal collapse is high in brachycephalic dogs undergoing videofluoroscopy

The aim of this retrospective study was to determine the frequency of pharyngeal collapse in a large group of brachycephalic dogs undergoing videofluoroscopic assessment of swallowing or airway diameter. We hypothesized that brachycephalic dogs would have pharyngeal collapse more frequently than dolichocephalic or mesocephalic dogs with or without airway collapse. The medical records database was searched for brachycephalic dogs undergoing videofluoroscopy of swallowing or airway diameter between January 1, 2006 and December 31, 2015. A cohort of dolichocephalic/mesocephalic dogs with videofluoroscopically confirmed airway collapse was age and time matched for comparison. A control group of dolichocephalic/mesocephalic dogs that did not have documented airway collapse was also evaluated. All fluoroscopic studies were assessed by a board certified veterinary radiologist for the presence and degree of pharyngeal collapse. Results demonstrate that pharyngeal collapse was significantly more common in brachycephalic dogs (58/82; 72%) than in nonbrachycephalic dogs with (7/25; 28%) and without (2/30; 7%) airway collapse. Pharyngeal collapse is more prevalent in brachycephalic dogs undergoing videofluoroscopy than in dolichocephalic/mesocephalic dogs with or without airway collapse.

Posterior Tracheopexy for Severe Tracheomalacia Associated with Esophageal Atresia (EA): Primary Treatment at the Time of Initial EA Repair versus Secondary Treatment

Purpose

We review outcomes of posterior tracheopexy for tracheomalacia in esophageal atresia (EA) patients, comparing primary treatment at the time of initial EA repair versus secondary treatment.

Methods

All EA patients who underwent posterior tracheopexy from October 2012 to September 2016 were retrospectively reviewed. Clinical symptoms, tracheomalacia scores, and persistent airway intrusion were collected. Indication for posterior tracheopexy was the presence of clinical symptoms, in combination with severe tracheomalacia as identified on bronchoscopic evaluation, typically defined as coaptation in one or more regions of the trachea. Secondary cases were usually those with chronic respiratory symptoms who underwent bronchoscopic evaluation, whereas primary cases were those found to have severe tracheomalacia on routine preoperative dynamic tracheobronchoscopy at the time of initial EA repair.

Results

A total of 118 patients underwent posterior tracheopexy: 18 (15%) primary versus 100 (85%) secondary cases. Median (interquartile range) age was 2 months (1–4 months) for primary (22% type C) and 18 months (8–40 months) for secondary (87% type C) cases (p < 0.001). There were statistically significant improvements in most clinical symptoms postoperatively for primary and secondary cases, with no significant differences in any postoperative symptoms between the two groups (p > 0.1). Total tracheomalacia scores improved significantly in primary (p = 0.013) and secondary (p < 0.001) cases. Multivariable Cox regression analysis indicated no differences in persistent airway intrusion requiring reoperation between primary and secondary tracheopexy adjusting for imbalances in age and EA type (p = 0.67).

Conclusion

Posterior tracheopexy is effective in treating severe tracheomalacia with significant improvements in clinical symptoms and degree of airway collapse on bronchoscopy. With no significant differences in outcomes between primary and secondary treatment, posterior tracheopexy should be selectively considered at the time of initial EA repair.

Exercise-associated Excessive Dynamic Airway Collapse in Military Personnel

RATIONALE

Evaluation of military personnel for exertional dyspnea can present a diagnostic challenge, given multiple unique factors that include wide variation in military deployment. Initial consideration is given to common disorders such as asthma, exercise-induced bronchospasm, and inducible laryngeal obstruction. Excessive dynamic airway collapse has not been reported previously as a cause of dyspnea in these individuals.

OBJECTIVES

To describe the clinical and imaging characteristics of military personnel with exertional dyspnea who were found to have excessive dynamic collapse of large airways during exercise.

METHODS

After deployment to Afghanistan or Iraq, 240 active U.S. military personnel underwent a standardized evaluation to determine the etiology of persistent dyspnea on exertion. Study procedures included full pulmonary function testing, impulse oscillometry, exhaled nitric oxide measurement, methacholine challenge testing, exercise laryngoscopy, cardiopulmonary exercise testing, and fiberoptic bronchoscopy. Imaging included high-resolution computed tomography with inspiratory and expiratory views. Selected individuals underwent further imaging with dynamic computed tomography.

MEASUREMENTS AND MAIN RESULTS

A total of five men and one woman were identified as having exercise-associated excessive dynamic airway collapse on the basis of the following criteria: (1) exertional dyspnea without resting symptoms, (2) focal expiratory wheezing during exercise, (3) functional collapse of the large airways during bronchoscopy, (4) expiratory computed tomographic imaging showing narrowing of a large airway, and (5) absence of underlying apparent pathology in small airways or pulmonary parenchyma. Identification of focal expiratory wheezing correlated with bronchoscopic and imaging findings.

CONCLUSIONS

Among 240 military personnel evaluated after presenting with postdeployment exertional dyspnea, a combination of symptoms, auscultatory findings, imaging, and visualization of the airways by bronchoscopy identified six individuals with excessive dynamic central airway collapse as the sole apparent cause of dyspnea. Exercise-associated excessive dynamic airway collapse should be considered in the differential diagnosis of exertional dyspnea.

Computer quantification of "angle of collapse" on maximum expiratory flow volume curve for diagnosing asthma-COPD overlap syndrome

Background

In a previous study, we demonstrated that asthma patients with signs of emphysema on quantitative computed tomography (CT) fulfill the diagnosis of asthma-COPD overlap syndrome (ACOS). However, quantitative CT measurements of emphysema are not routinely available for patients with chronic airway disease, which limits their application. Spirometry was a widely used examination tool in clinical settings and shows emphysema as a sharp angle in the maximum expiratory flow volume (MEFV) curve, called the “angle of collapse (AC)”. The aim of this study was to investigate the value of the AC in the diagnosis of emphysema and ACOS.

Methods

This study included 716 participants: 151 asthma patients, 173 COPD patients, and 392 normal control subjects. All the participants underwent pulmonary function tests. COPD and asthma patients also underwent quantitative CT measurements of emphysema. The AC was measured using computer models based on Matlab software. The value of the AC in the diagnosis of emphysema and ACOS was evaluated using receiver-operating characteristic (ROC) curve analysis.

Results

The AC of COPD patients was significantly lower than that of asthma patients and control subjects. The AC was significantly negatively correlated with emphysema index (EI; r=−0.666, P<0.001), and patients with high EI had a lower AC than those with low EI. The ROC curve analysis showed that the AC had higher diagnostic efficiency for high EI (area under the curve =0.876) than did other spirometry parameters. In asthma patients, using the AC ≤137° as a surrogate criterion for the diagnosis of ACOS, the sensitivity and specificity were 62.5% and 89.1%, respectively.

Conclusion

The AC on the MEFV curve quantified by computer models correlates with the extent of emphysema. The AC may become a surrogate marker for the diagnosis of emphysema and help to diagnose ACOS.

Clinical usefulness of watch-PAT for assessing the surgical results of obstructive sleep apnea syndrome

OBJECTIVE

This study aimed to assess the accuracy and clinical efficacy of a wrist-worn device that is based on peripheral arterial tonometry (watch-PAT) to evaluate the surgical results of obstructive sleep apnea (OSA) syndrome subjects.

STUDY DESIGN AND METHOD

Thirty-five subjects who were diagnosed with OSA and underwent sleep surgeries such as septoplasty, tonsillectomy, or uvuloplasty to correct their airway collapse, participated in this study; the watch-PAT-derived respiratory disturbance index (RDI), apnea and hypopnea index (AHI), lowest oxygen saturation, and valid sleep time were measured after the sleep surgery.

RESULTS

The present study showed that RDI (32.8 ± 10.7 vs. 14.8 ± 7.5), AHI (30.3 ± 8.6 vs. 13.4 ± 8.2 events/h), lowest oxygen saturation (78.2% ± 8.4% vs. 90.5% ± 7.1%), and valid sleep time (329.1 ± 47.2 min and a postoperative value of 389.1 ± 50.1 min) recovered to within a normal range after surgery in 28 subjects. In addition, good agreement was found between watch-PAT-derived factors and visual analogue scales for changes in subjective symptoms, such as snoring, apnea, and daytime somnolence. Seven of the 35 subjects showed no improvement for their subjective symptoms and complained of snoring and apnea after surgery. We found that the RDI and AHI of those 7 subjects were not reduced, and the changes between pre- and postoperative values which were measured with watch-PAT were minimal. Their postoperative lowest oxygen saturation and valid sleep time were not elevated per the watch-PAT. The results support a strong correlation between the findings from watch-PAT and improved symptoms after surgical correction of an airway collapse.

CONCLUSIONS

Our study provides evidence that the factors measured by the watch-PAT might be reliable indicators of symptomatic changes in OSA subjects after sleep surgery and also shows that the watch-PAT is a highly sensitive portable device for estimating treatment results in OSA.