Noise exposure in pediatric otolaryngology clinic: A sound survey of a single-institution tertiary care facility.

BACKGROUND: The Occupational Safety and Health Administration (OSHA) considers acoustic exposure of 90 decibels (dB) an occupational risk for noise-induced hearing loss. Pediatric healthcare clinicians are exposed to considerable noise especially during invasive procedures, predisposing them to noise-induced hearing loss, increased work-related stress, and increased complications associated with intense noise exposure. While there has been extensive research in noise exposure in dentistry, to date there has been no research on noise exposure in the pediatric otolaryngology clinic setting. The objective of this study is to quantify the degree of noise exposure that pediatric otolaryngologists encounter in the clinical setting. METHODS: A sound survey was performed of 420 pediatric otolaryngology clinic visits within a single-institution tertiary care facility from January 2022 to March 2022, with a total of 409 visits included. At each visit, noise was measured using a calibrated National Institute for Occupational Safety and Health (NIOSH) Sound Meter application, an iPad, and a microphone. The Equivalent Continuous Sound Pressure Level (LAeq), peak sound pressure level (SPL), C-weighted peak noise level (LCpeak), and the 8-hour time-weighted average (TWA) sound level were recorded. RESULTS: The average LAeq was 61.1 dB, the median LAeq was 60.3 dB, and the average peak SPL was 80.5 dB. Only 0.5 % of visits reached an LAeq above 80 dB, however, 51 % were above 60 dB and 99 % were above 45 dB. No clinicians were exposed to noise exceeding established limits of safety. Patients younger than ten years old (p < 0.001) and those who underwent procedures such as cerumen removal (p < 0.001) elicited higher ranges of elevated noise. Multivariate analysis confirmed that increased age decreased acoustic exposure while procedures increased acoustic exposure. CONCLUSIONS: The results of this study suggest that pediatric otolaryngology clinicians do not exceed hazardous noise limit exposure. However, they are exposed to levels above those which have been linked to stress, poor productivity, and stress-related disorders. This analysis also reports that patients who are younger and those that undergo procedures, specifically cerumen removal, tend to expose their providers to the highest levels of noise. This is the first study examining noise exposure in pediatric otolaryngology, and further research should evaluate the risks of noise exposure in this environment.

Reducing intraoperative time with laryngeal mask airway and stretcher in pediatric adenotonsillectomy.

OBJECTIVES: Adenotonsillectomy (T&A) is one of the most common surgical procedures performed in the United States. Several studies have defined the safety of laryngeal mask airway (LMA) during this surgery, and conflicting evidence exists describing the role it plays in reducing intraoperative times. Our objective is to describe the role LMA and operating on a stretcher have on reducing intraoperative time during pediatric T&A. METHODS: This is a retrospective review between October 2017 and January 2020. We included patients between the ages of 4-18 years old undergoing T&A. We excluded medically complex patients with chromosomal, craniofacial, and metabolic abnormalities, patients with cerebral palsy, and those who were tracheostomy dependent. Patient demographics included surgical indication, age, sex, obesity, use of preoperative midazolam, type of airway used, use of traditional operating room (OR) bed versus transport stretcher, surgeon type, and intraoperative times. Data was analyzed with univariate t-test and multivariate linear regression. RESULTS: One hundred seventy-nine patients were included with an average age of 7.2 years. LMA and stretcher were used on 46.4% and 40.2% of patients, respectively. On multivariate linear regression LMA reduced emergence time by 4.4 min (p ≤ 0.001, 95% CI -6.7 to -2.1) and transport stretcher reduced induction time by 2.5 min (p = 0.04, 95% CI -4.9 to -0.1). Use of LMA and stretcher did not have a statistically significant difference on actual procedure time. CONCLUSION: Our study further supports the role LMA has in reducing intraoperative times in addition to describing a novel method of reducing intraoperative time by operating on a transport stretcher for healthy children undergoing T&A. LEVEL OF EVIDENCE: 3.

Pediatric tracheostomies in patients less than 2 years of age: Analysis of complications and long-term follow-up.

PURPOSE: Identify variables that are predictive of morbidity and mortality in children under the age of two undergoing tracheostomy and to provide longitudinal data on this patient population. METHODS: Patients were retrospectively identified using Current Procedural Terminology codes 31600, 31601, 31610 from 2009 to 2016. RESULTS: Median age at time of tracheostomy was 0.43 years (interquartile range, 0.27-0.61). Patients were followed for a median of 1.39 years (range 0.03-4.25). Overall mortality rate in this cohort was 23.5% with the majority (81.3%) of deaths occurring >30 days following tracheostomy. The most frequently encountered major complication was cardiopulmonary arrest (10.29%) in the short-term follow up period (<30 days) and accidental decannulation (32.81%) during long-term follow up (>30 days). Peristomal skin breakdown was less likely to develop in patients who did not receive paralytics following tracheostomy. Most patients (54.4%) were discharged to home following initial admission and experienced a mean of 2.10 readmissions for any reason during the follow-up period. 64.4% of patients underwent surveillance direct laryngoscopy and bronchoscopy during the follow-up period and suprastomal granuloma formation was detected in 31.2% of these patients. 9 patients underwent decannulation at a median of 2 years from original tracheostomy placement. CONCLUSION: Pediatric patients under the age of 2 undergoing tracheostomy exhibit high morbidity during both the initial hospital admission and the subsequent months following discharge. However, major complications were low and mortality was not directly related to tracheostomy status in any case.

Effect of changing postoperative pain management on bleeding rates in tonsillectomy patients.

PURPOSE: To review rates of post-tonsillectomy hemorrhage (PTH) at a quaternary medical center, including the impact of narcotic versus nonsteroidal anti-inflammatory drug (NSAID) postoperative pain management. MATERIALS AND METHODS: A retrospective review was performed of tonsillectomies conducted at a single institution between 1/1/2013 and 1/1/2017. The rates of PTH and subsequent intervention were calculated. These were categorized into patients having surgery pre- and post-July 1, 2015, the former group receiving narcotics and the latter ibuprofen with acetaminophen. RESULTS: Of 1351 total tonsillectomies, 3.04% had PTH requiring return to the hospital. 0.74% required no further surgical intervention, whereas 2.30% required secondary surgical control. The bleed rate prior to July 2015 was 3.15%, with 1.05% non-surgical bleeds and 2.10% requiring surgery. Post-July 2015, the bleed rate was 2.92%, with 0.44% non-surgical bleeds and 2.49% requiring surgery. There were no statistically significant differences between the two groups with respect to overall, non-surgical, and surgical hemorrhage rates (p > 0.05). Of the total bleeds, the need for secondary surgery in the narcotic group was 66.7% and 85% in the NSAID group (p = 0.18). During the study period, 36 patients with PTH had their initial tonsillectomy performed at outside institutions; 53% required surgical intervention. CONCLUSIONS: Secondary hemorrhage remains a significant cause of morbidity in post-tonsillectomy patients, often requiring surgical intervention. This review found no increased bleeding risk associated with use of ibuprofen and acetaminophen as opposed to narcotic pain relief. LEVEL OF EVIDENCE: III.

DNA damage in children with obstructive adenotonsillar hypertrophy.

The objective of this prospective, controlled study was to evaluate oxidative DNA damage in children with obstructive adenotonsillar hypertrophy. This study included 30 patients with obstructive adenotonsillar hypertrophy (male/female ratio, 3:2; age range, 3-9 y) scheduled to undergo tonsillectomy and adenoidectomy and 25 control subjects of similar age and sex with no adenotonsillar disease or airway obstruction. Urine and blood samples were obtained from each child for 8-hydroxy 2-deoxyguanosine (8-OhdG) and malondialdehyde (MDA) concentrations. There were significant differences in leukocyte (3.28 [0.69/10] vs 0.70 [0.15/10] dG) and urine 8-OhdG (8.22 [2.27/10] vs 5.26 [1.3/10] dG) levels in patients with obstructive adenotonsillar hypertrophy and healthy subjects (P < 0.001 for both). Plasma (2.98 [1.31] vs 1.14 [0.64] µM) and urine (1.77 [0.84] vs 0.56 [0.32] µM) MDA levels were also different (P < 0.001 for both). There were positive correlations between 8-OhdG in leukocyte DNA and plasma MDA (r = 0.648, P < 0.001) and between levels of urine 8-OhdG excretion and urine MDA (r = 0.588, P < 0.001). The DNA damage in children with adenotonsillar hypertrophy should be kept in mind, but further studies must be done with larger patient groups.

Management of pediatric choanal atresia restenosis and subglottic stenosis using steroid-eluting stents.

OBJECTIVES: To depict the novel use of steroid-eluting stents in the treatment of choanal atresia (CA) restenosis and subglottic stenosis (SGS). METHODS: A retrospective chart review of three pediatric patients, one with CA and two with SGS, treated with mometasone furoate eluting mini stents (PROPEL) was performed. Patients were evaluated for restenosis and adverse events between one to twelve months postoperatively. RESULTS: Postoperatively, patient one with CA showed no signs of restenosis and required no further intervention. Patient two with SGS demonstrated an open subglottic lumen with no signs of restenosis as well as improved phonation following his planned serial procedures. Post-operatively, patient three with SGS exhibited no restenosis of the subglottic lumen, tolerated intermittent tracheostomy capping, and demonstrated improved phonation. CONCLUSION: In this case series, we outline successful treatments for the management of CA restenosis and SGS with mometasone furoate-eluting stents. To our knowledge, this is the first reported application of this treatment in pediatric patients with CA restenosis and the second reported application in pediatric patients with SGS.

Does lack of glottic closure affect quality of life as a cause of constipation in laryngectomized patients?

The permanent disappearance of glottic closure eventually causes inadequate defecatory propulsion resulting in functional constipation. The aim of this study is to reveal functional constipation probably induced by lack of glottic closure in laryngectomized patients. The study was conducted in a prospective, tertiary care center. Forty patients who had undergone total laryngectomy (study group) and 30 who had undergone microlaryngoscopic surgery (control group) were evaluated. Based on the European Organisation for Research and Treatment of Cancer, Quality of Life Questionnaires C30, the presence of functional constipation was investigated using the Rome II diagnostic criteria and was confirmed by measurement of colonic transit time using a radiopaque marker test. Functional constipation and colonic transit time were found to be increased and statistically significant in laryngectomized patients (70 %) compared with the control group (26 %) (p < 0.01). Functional constipation is more prevalent among laryngectomized patients. When evaluating quality of life of patients undergoing laryngectomy, colorectal functions must be taken into consideration.

The application of simultaneous mainstem bronchus dilation with pulmonary artery stenting in the context of hypoplastic left heart syndrome.

Hypoplastic left heart syndrome (HLHS) is a congenital diagnosis that necessitates immediate intervention at the beginning of life to ensure survival past infancy and to optimize left-side cardiac function. Often, these required procedures can lead to deleterious side effects and resultant complications. In this case report, we present a 15-month-old patient with HLHS who underwent multiple procedures, including two aortic arch surgeries. After the interventions, the patient experienced left main pulmonary bronchus compression along with pulmonary artery stenosis. In this case, we outline an approach to performing vascular dilation without compromise of airway patency.

CO(2) gas exchange across the human tympanic membrane is not appreciably affected by pathology.

Past in vivo studies in humans showed that the tympanic membrane (TM) is permeable to physiological gases. Animal studies show that transTM CO(2) conductance is increased by TM pathology. The objective of the study was to determine if transTM CO(2) exchange in humans is affected by atrophic and sclerotic pathologies. The study used an ear canal (EC) probe (ECP) constructed from a custom-fitted acrylic body, a glass capillary tube enclosing an oil meniscus to maintain ambient ECP + EC pressure and a silica glass microtube linked to a mass spectrometer (MS) for measuring gas composition that was hermetically sealed within the ear canal of the test ear. ECP + EC volume was measured and gas samples taken at 10 min intervals for 1 h. The fractional CO(2) pressure measured in the ECP + EC for each sample was regressed on time and the slope of the function multiplied by the ECP + EC volume and divided by the estimated transTM CO(2) gradient at the start of the experiment to yield transTM CO(2) conductance (microL/min/Pa). Data were complete for 15 normal, 13 sclerotic and 9 atrophic TMs. The average (+std) transTM CO(2) conductances were 1.76 × 10(-4) + 7.27 × 10(-5), 2.26 × 10(-4) + 1.5 × 10(-4) and 2.36 × 10(-4) + 1.14 × 10(-4) microL/min/Pa/TM for the normal, sclerotic and atrophic TMs, respectively. A pairwise comparison of data for the normal and atrophic TMs under the directional hypothesis of a greater CO(2) exchange rate for thinner TMs approached statistical significance (P = 0.07). A similar pairwise comparison for the sclerotic and normal TMs did not approach statistical significance (P = 0.28). The effect of TM pathologies on CO(2) conductance was limited.

Traumatic xylophagia leading to foreign body removal and tracheostomy in the setting of postpartum psychosis.

Postpartum psychosis (PPP) is a severe mood disorder following childbirth that rarely leads to injurious or suicidal behavior. This report illustrates otolaryngologic intervention for pharyngeal laceration and airway instability following traumatic foreign body ingestion in the setting of PPP. A 25-year-old woman with PPP presented with hemoptysis after attempting suicide by traumatically forcing tree branches into her oropharynx. Imaging revealed pneumomediastinum, and flexible laryngoscopy and esophagoscopy showed a large foreign body (tree branch) extending from the hypopharynx to the gastroesophageal junction. She was taken to the operating room for direct microlaryngoscopy, bronchoscopy and esophagoscopy with removal of the 25-cm tree branch. Panendoscopy revealed a mucosal laceration at the cricopharyngeus with supraglottic and hypopharyngeal edema but no injury to the larynx. Due to airway concerns, a cuffed tracheostomy was placed along with a gastrostomy tube for feeding access. She tolerated her postoperative course with successful decannulation and oral feeding prior to discharge.

Early Tracheostomy Change in Neonates: Feasibility and Benefits.

OBJECTIVES: To compare outcomes of early and late tracheostomy change in neonatal patients. Early tracheostomy change (ETC) occurred 3 to 4 days after surgery, and late tracheostomy change (LTC) occurred 5 to 7 days after surgery. STUDY DESIGN: Retrospective cohort. SETTING: Tertiary neonatal/pediatric intensive care unit. METHODS: A retrospective review of patients who underwent tracheostomy from 2015 to 2019 was performed for infants <1 year old. Data were recorded regarding age at tracheostomy, days until tracheostomy tube change, postoperative complications, and total number of days on sedative or paralytic drugs. RESULTS: Forty-six patients were included: 18 (39%) were male, with a mean age of 140 days (SD, 78). Of these, 28 (61%) received ETC. There were no accidental decannulation events in either group. Wound breakdown developed in 4 (14%) patients with ETC versus 5 (28%) with LTC (P = .3). Use of FlexTend tracheostomy tubes was associated with decreased odds of breakdown (odds ratio, 0.03; P = .01). Postoperatively, 46 (100%) patients received sedation, and 12 (26%) received paralysis. Mean duration of paralysis was 0.5 days in ETC as opposed to 2.2 days in LTC (P = .02) on univariate analysis, but the significance was not maintained on multivariate regression (P = .07). CONCLUSIONS: ETC appears to be feasible in children less than a year of age. There does not appear to be an increased risk of accidental decannulation events or false passage tracts. Further investigations are warranted to investigate safety and possible impact on wound breakdown.

Airway evaluation in children with single ventricle cardiac physiology.

OBJECTIVE: Children with single ventricle cardiac physiology (SVC) often require airway procedures as an adjunct to their care. Descriptive analysis with a focus on outcomes of airway procedures in SVC patients have not been fully described in the literature. METHODS: Retrospective, single-center cohort review of 270 patients born between Aug-2007 and Jan-2017. Patients were identified by cardiac database for single ventricle pathophysiology. A subset of these patients were identified to have been evaluated by otolaryngology with airway evaluations and/or interventions. RESULTS: 88/270 patients (32.6%) required investigation or intervention for airway pathology. The most frequent procedure was flexible fiberoptic laryngoscopy (58/88 patients); it was the only procedure performed in 40 patients. Seventeen patients required tracheostomies with an associated increased length of stay (p < 0.001). Patients with cardiac procedures involving dissection around the aortic arch were considered higher airway risk due to the threat of recurrent laryngeal nerve injury, and were more likely to have vocal cord paralysis (58%) compared to patients with lower risk procedures (21%; p < 0.001). However, on multivariate logistic regression, vocal cord paralysis did not statistically impact the odds for tracheostomy placement, although the presence of subglottic stenosis increased the odds ratio of tracheostomy by 14.7 (p = 0.02). CONCLUSIONS: Children with SVC often require airway evaluation and intervention. Patients with high risk cardiac procedures had a higher risk of recurrent laryngeal nerve injury but the presence of subglottic stenosis was the best predictor for a tracheostomy. This study represents one of the largest series of SVC children evaluated for airway pathology.

Effects of ciprofloxacin-dexamethasone on myringotomy wound healing.

OBJECTIVE: To evaluate the effects of the ciprofloxacin-dexamethasone (CDX) combination ototopical treatment after myringotomy on tympanic membrane (TM) healing in ears with eustachian tube obstruction (ETO) and unobstructed ears. STUDY DESIGN: Prospective, randomized, masked, controlled. METHODS: ETO was created in the left ear of 30 rats to induce a model of otitis media with effusion (OME). After 3 weeks, bilateral myringotomy was performed (day 0). Animals were randomized into three groups to receive no treatment or bilateral once daily ototopical treatment with balanced salt solution (BSS, vehicle) or CDX for 13 days. Bilateral otomicroscopy was performed on days 7, 14, and 28. On day 14, five randomly selected animals per group were humanely euthanized and the TM harvested for histology. Three additional rats provided normal negative control ears for histologic comparisons. RESULTS: On day 14, TM perforation healing rates were 100% in all ears of untreated and BSS-treated animals, 89% (8/9) in CDX-treated obstructed ears, and 30% (3/10) in CDX-treated unobstructed ears (P < .05 vs. BSS). On day 28, 100% (5/5) of the CDX-treated unobstructed ears and 80% (4/5) of the CDX-treated obstructed ears were healed. Histology showed initial TM thickening postmyringotomy in all ears but no significant qualitative differences between groups on day 28. CONCLUSION: Myringotomy healing was transiently modulated by treatment with CDX but proceeded normally after CDX discontinuation. This early modulation might enhance middle ear drainage and middle ear concentrations of CDX when tympanostomy tube surgery is performed in patients with active OME and ETO, thus potentially reducing otorrhea and preventing or treating infection. It would not be expected to increase the risk of premature tube extrusion or adversely affect normal healing of the TM after usual spontaneous extrusion.

Directional asymmetry in the measured nitrous oxide time constant for middle ear transmucosal gas exchange.

OBJECTIVES: Simple, 2-compartment mathematical models of middle ear (ME) transmucosal gas exchange reproduce observed ME pressure behavior. These models require input of an experimentally determined, lumped-parameter exchange constant for each represented gas species. Previous model applications assumed directional asymmetry for those parameters, which has not been experimentally validated. METHODS: As a surrogate for the inert gas nitrogen (N2), for which exchange is too slow to be measurable, the nitrous oxide (N2O) transmucosal exchange constant for 16 ears of 8 monkeys was measured for positive and negative ME blood N20 gradients. RESULTS: The paired exchange constants for each ear were highly correlated, but the ME-blood/blood-ME exchange constant ratio was approximately 13. Modeling shows this asymmetry to depend on the value of the arterial-venous/arterialME ratio, a variable in the exchange constant for perfusion-limited gases. CONCLUSIONS: These results support an asymmetric rate of transmucosal N20 and, by extension, N2 exchange for the ME. Because the primary controlling parameter for ME pressure behavior in the absence of eustachian tube opening is the rate of transmucosal N2 exchange, this effect needs to be incorporated into the simple 2-compartment exchange models for predictive accuracy. The gradient ratio dependence suggests that parameter-free modeling may require treating the ME mucosa as having a distributed gradient for certain gas species.

Accuracy of CO2 conductance predicted using a morphometric model of the middle ear mucosa.

CONCLUSION: These results hold promise that morphometric analysis can be used to generate transMEM (middle ear mucosa) gas conductance estimates for MEM geometries representative of the shift from healthy to pathologic states (e.g. increased MEM thickness and capillary density). OBJECTIVES: Novel strategies to treat otitis media with effusion require a better understanding of how MEM geometry affects gas transport. Earlier studies developed techniques to empirically measure transMEM gas conductance and to estimate conductance using morphometric models of MEM geometry. We used chinchillas to determine the correspondence between experimentally measured transMEM CO2 conductance and that predicted by morphometric study of the MEM. MATERIALS AND METHODS: TransMEM CO2 conductance was measured unilaterally in 10 chinchillas; the animals were killed and the ME was removed and processed for morphometric analyses of MEM geometry. RESULTS: The average measured and estimated transMEM CO2 conductances were 4.87+/-2.30 x 10-10 and 1.75+/-0.29 x 10-10 mol/s/mmHg, respectively. The magnitude and direction of the estimate error were similar for all ears, suggesting a fixed, negative bias to the estimate. A theoretically consistent source for this bias was identified as the representation of the true diffusional length within a 3-D geometry using a 2-D modeling platform. Best estimate correction for this effect based on available data significantly reduced the estimate bias.

Nasal prostaglandin challenge increases N2O exchange from blood to middle ear.

Nasal inflammation (NI) resulting from allergy or virus infection is causally associated with otitis media. Impaired Eustachian tube (ET) function consequent to NI may mediate this relationship. Moreover, the functional demand placed upon the ET for gas supply may be increased by NI, a hypothesis tested here. A total of five experiments were done at a minimum 2-week interval on four monkeys. For each experiment, the monkey was anesthetized and acclimated for 60 min. Then, the monkey was breathed with a 40% N2O gas mixture for 60 min followed by air breathing for 100 min. Fifteen minutes into air breathing, the nose was challenged with one of the five substances: saline, PGD2, capsaicin, histamine or bradykinin. Throughout, middle ear (ME) pressures were recorded at 5-min intervals. All pressure-time curves had a similar form consisting of a curvilinear decrease during acclimation, a linear increase during N2O breathing and a linear decrease during air breathing. The rates of pressure increase were ear-specific and not different across experiments. Compared to saline, the rate of pressure decrease was greater for challenge with all the substances and significantly greater after PGD2 challenge. Like N2, N2O is an inert gas whose transmucosal exchange is perfusion-limited for the ME. The measured pressure change is linearly related to the volume gas exchange between ME and blood. Therefore, nasal challenge with PGD2 and perhaps the other substances increases transmucosal inert gas exchange. ME to blood N2 transfer rate determines the physiological demand placed upon the ET for gas supply. That demand is increased by nasal exposure to certain inflammatory mediators.

Applications for transoral robotic surgery in the pediatric airway.

OBJECTIVES/HYPOTHESIS: To report preliminary experience in the utilization of transoral robotic surgical (TORS) techniques in pediatric airway surgery. STUDY DESIGN: Retrospective case series. METHODS: A retrospective chart review was performed on all pediatric patients undergoing robotic airway surgery at a university-based children's hospital between August 2010 and December 2012. RESULTS: Three pediatric patients underwent robotic repair of various airway anomalies between August 2010 and December 2012. Case 1 is a 15-year-old boy with posterior glottic stenosis for which a robotic-assisted posterior cricoid split with cartilage graft placement was attempted but ultimately required conversion to an open technique. Case 2 is a 6-year-old male with Trisomy 21 who had robotic-assisted endoscopic repair of a type II laryngeal cleft, with subsequent resolution of his chronic aspiration and successful initiation of oral feeding. Case 3 is a 3-year-old female who underwent robotic-assisted left posterior cordectomy and subtotal arytenoidectomy for idiopathic bilateral vocal cord paralysis, resulting in improved Passy-Muir valve tolerance. CONCLUSION: TORS is being increasingly utilized in the field of head and neck surgery as it is frequently less invasive and often demonstrates improved outcomes compared with traditional approaches. This study details our experience utilizing TORS in the management of pediatric airway anomalies and represents one of the earliest such series in the literature. Although TORS has the potential to improve the management of pediatric airway disorders, larger, prospective studies are needed to better elucidate its feasibility and efficacy. LEVEL OF EVIDENCE: 4.

Resolution of airflow obstruction on polysomnography after laryngotracheal reconstruction with anterior tracheal wall suspension in a patient with DiGeorge Syndrome.

DiGeorge Syndrome (DGS) may be associated with airway abnormalities including laryngomalacia and suprastomal collapse of the trachea (SCT), which may lead to sleep disordered breathing (SDB). We present a 4-year-old boy with DGS, SCT, and SDB by polysomnography (PSG) while the tracheostomy tube was capped. The patient underwent anterior tracheal wall suspension (ATWS) with concurrent tracheostomy decannulation. Following the repair, the patient experienced improved airway patency visually and by PSG with resolution of obstructive sleep apnea and hypoventilation. ATWS is an effective method to repair SCT in selected patients and may lead to early decannulation and improvement of SDB.

Transmucosal O2 and CO2 exchange rates for the human middle ear.

OBJECTIVE: Estimate the transmucosal CO(2) and O(2) rate-constants for adult middle ears (MEs). METHODS: Ten adults with healthy MEs had a unilateral myringotomy. A custom-fitted acrylic mold with a valved line to a mass spectrometer (MS) and central tube coupled to a 3-way valve and connected to a pressure transducer (the probe) was sealed with adhesive glue within the ipsilateral ear-canal. A second 3-way valve was attached to the probe valve, a flow-regulated tank gas source and paired syringes. Volumes of the ME and probe were measured. On sequential days, the probe+ME was washed for 15-min with 6% O(2), Balance N(2) and 25% O(2), 6% CO(2), Balance N(2) to create transmucosal CO(2) and O(2) gradients, respectively. After washing, the probe+ME was isolated from the gas source, and baseline and 10-min gas samples were obtained for MS analysis of gas partial-pressures. The rates of change in ME CO(2) and O(2) pressures were divided by their established transmucosal gradients to yield CO(2) and O(2) rate-constants. RESULTS: The average (±STD) transmucosal CO(2) and O(2) rate-constants were 0.062 ± 0.034 (N=10, range: 0.032-0.119) and 0.011 ± 0.009 (N=8, range: 0.002-0.032)mmHg/min/mmHg, respectively. The average half-life for the CO(2) and O(2) gradient was 11.1 and 61.6 min. The average CO(2):O(2) rate-constant ratio was 8.1 ± 4.0 (N=8, range: 3.6-14.6). CONCLUSIONS: For adult human MEs, transmucosal CO(2) exchange is rapid and much faster than transmucosal O(2) exchange. The estimated CO(2)/O(2) rate-constant ratio for the human ME is not consistent with that predicted for diffusion-limited gas exchange across a water-based barrier.