Dexamethasone eluting polydopaminated polycaprolactone-poly (lactic-co-glycolic) acid for treatment of tracheal stenosis

Tracheal stenosis is commonly caused by injury, resulting in inflammation and fibrosis. Inhibiting inflammation and promoting epithelization can reduce recurrence after initial successful treatment of tracheal stenosis. Steroids play an important role in tracheal stenosis management. This study in vitro evaluated effectiveness of a polydopaminated polycaprolactone stent coated with dexamethasone-eluting poly(lactic-co-glycolic) acid microparticles (μPLGA) for tracheal stenosis management. Polydopamination was characterized by Raman spectroscopy and promoted epithelialization while dexamethasone delivery reduced macrophage activity, assessed by individual cell area measurements and immunofluorescent staining for inducible nitric oxide synthase (iNOS). Dexamethasone release was quantified by high-performance liquid chromatography over 30 days. Activation-related increase in cell area and iNOS production by RAW 264.7 were both reduced significantly (p < .05) through dexamethasone release. Epithelial cell spreading was higher on polydopaminated polycaprolactone (PCL) than PCL-alone (p < .05). Force required for stent migration was measured by pullout tests of PCL-μPLGA stents from cadaveric rabbit and porcine tracheas (0.425 ± 0.068 N and 1.082 ± 0.064 N, respectively) were above forces estimated to occur during forced respiration. Biomechanical support provided by stents to prevent airway collapse was assessed by comparing compressive circumferential stiffness, and stiffness of the stent was about 1/10th of the rabbit trachea (0.156 ± 0.023 N/mm vs. 1.420 ± 0.194 N/mm, respectively). A dexamethasone-loaded PCL-μPLGA stent platform can deliver dexamethasone and exhibits sufficient mechanical properties to anchor within the trachea and polydopamination of PCL is conducive to epithelial layer formation. Therefore, a polydopaminated PCL-μPLGA stent is a promising candidate for in vivo evaluation for treatment of tracheal restenosis.

Application of OFA-based ERAS for video-assisted thoracoscopic surgery in elderly patients with airway stenosis: A case report

BACKGROUND

Thoracic surgery without general anesthesia can be traced back to the First World War, and thoracic epidural block was used to complete the operation due to a large number of patients with gunshot wounds who needed emergency thoracic surgery. By reducing the intraoperative opioid dose, intraoperative and postoperative opioid-related adverse events such as respiratory depression, nausea and vomiting, delirium, hyperalgesia, and other side effects can be reduced to the benefit of patients.

METHODS

A 72-year-old male patient was admitted to the hospital with a 5-day history of multifocal pain throughout the body caused by a fall. The injury was not treated at that time, and the pain gradually increased, accompanied by cough with difficulty expelling sputum.

DIAGNOSES

Left lung contusion; traumatic pneumonia; multiple left rib fractures; left fluid pneumothorax; thyroid tumor of unknown nature, possibly malignant. Grade I tracheal stenosis; Sequelae of cerebral infarction. Because of goiter and severe tracheal compression, the patient was not intubated and received deopiated general anesthesia combined with epidural anesthesia to preserve spontaneous breathing.

OUTCOMES

At the end of the video-assisted thoracoscopic exploration, the patient was immediately conscious and returned directly to the ward 6 min later. The patient was able to move freely after surgery and eat normally within 6 h of surgery. The postoperative visual analog scale score was 2 points, and there were no anesthetic complications during the follow-up.

CONCLUSION

The opioid-free anesthesia strategy of tubeless general anesthesia, allowing spontaneous breathing combined with epidural anesthesia in elderly patients with tracheal stenosis undergoing video-assisted thoracoscopic surgery can not only avoid accidents and injuries caused by tracheal intubation and mechanical ventilation, but can also significantly reduce postoperative respiratory complications, optimize postoperative analgesia, and help achieve enhanced recovery after surgery.

[Acute respiratory distress due to tracheostomy tube migration]

Tracheostomy cannula care is of paramount importance in the daily management of tracheotomized patients. While some complications are commonplace, specific events can occur, often according to type of cannula. We herein report the case of a 71-year-old patient; following a lengthy stay in the intensive care unit, she had received a Safe T-Tube cannula designed to provide support in a stenotic trachea. At home, while suctioning her tracheal secretions, she suddenly experienced respiratory distress requiring a rapid intervention. On arrival, no seeable cannula was found, either in the tracheostomy or in the patient's immediate surroundings. Following her transfer to intensive care, a new cannula was inserted into the tracheostomy opening, enabling mechanical ventilation to begin and achieving rapid relief of dyspnea and improvement of the patient's overall condition. Bronchial fibroscopy was then performed, during which the Safe T-Tube cannula was found folded on itself in a supra-carinal intra-tracheal position. It was extracted and replaced by a cannula of the same model, which was sewn to the skin. Although rare and usually limited to flexible cannulas, this complication is potentially fatal. Generally speaking, when cannula obstruction is suspected, bronchial endoscopy in an intensive care setting is a vital necessity. It is not only the cornerstone of the diagnosis, but also of paramount importance in treatment taking into full account the mechanism of obstruction.

Nonmalignant tracheal stenosis: presentation, management and outcome in limited resources setting

BACKGROUND

Nonmalignant tracheal stenosis is a potentially life threatening conditions that develops as fibrotic healing from intubation, tracheostomy, caustic injury or chronic infection processes like tuberculosis. This is a report of our experience of its management with tracheostomy, rigid bronchoscopic dilation and surgery.

METHODS

Retrospective study design was used. 60 patients treated over five years period were included.

RESULTS

Mean age was 26.9 ± 10.0 with a range of 10-55 years. Majority (56 patients (93.3%)) had previous intubation as a cause for tracheal stenosis. Mean duration of intubation was 13.8 days (range from 2 to 27 days). All patients were evaluated with neck and chest CT (Computed Tomography) scan. Majority of the stenosis was in the upper third trachea - 81.7%. Mean internal diameter of narrowest part was 5.5 ± 2.5 mm, and mean length of stenosed segment was 16.9 ± 8 mm. Tracheal resection and end to end anastomosis (REEA) was the most common initial modality of treatment followed by bronchoscopic dilation (BD) and primary tracheostomy (PT). The narrowest internal diameter of the tracheal stenosis (TS) for each initial treatment category group was 4.4 ± 4.3 mm, 5.1 ± 1.9 mm and 6.7 ± 1.6 mm for PT, tracheal REEA and BD respectively, and the mean difference achieved statistical significance, F (10,49) = 2.25, p = 0.03. Surgery resulted in better outcome than bronchoscopic dilation (89.1% vs. 75.0%).

DISCUSSION AND CONCLUSION

Nonmalignant tracheal stenosis mostly develops after previous prolonged intubation. Surgical resection and anastomosis offers the best outcome.

Single stage pediatric airway reconstruction in solid organ transplant recipients

OBJECTIVES

To describe results of single stage laryngotracheal reconstruction (ssLTR) in patients with solid organ transplants and to discuss modifications which need to be considered in this subset of patients pre-operatively, intra-operatively and post-operatively.

STUDY DESIGN

We performed a retrospective case series review of children undergoing single stage laryngotracheal reconstruction in the context of prior solid organ transplant.

SETTING

A tertiary care academic setting.

METHODS

Pediatric cases undergoing Laryngotracheal reconstruction over a 3-year period. Demographic data including age, sex, presenting symptoms, operative details.

RESULTS

Two cases of ssLTR in solid organ transplant patients were found, one each with renal and cardiac transplants respectively. Both patients successfully underwent ssLTR for Grade 2 subglottic stenosis. The care of these patients was multidisciplinary and required alterations in their preoperative prophylactic antibiotics. While they did not require changes to the LTR post-operative sedation protocol, their immunosuppressant doses and target ranges were lowered. Special care was taken to avoid nephrotoxic and cardiotoxic medications throughout their hospital stay.

CONCLUSIONS

Although traditionally considered for double stage laryngotracheal reconstruction, single stage laryngotracheal reconstruction is a viable option in patients with solid organ transplant. These patients require a multidisciplinary approach and pharmacological protocol alterations pre-, intra-, and post-operatively.

Tracheal microbiome and metabolome profiling in iatrogenic subglottic tracheal stenosis

BACKGROUND

To study the role of microecology and metabolism in iatrogenic tracheal injury and cicatricial stenosis, we investigated the tracheal microbiome and metabolome in patients with tracheal stenosis after endotracheal intubation.

METHODS

We collected 16 protected specimen brush (PSB) and 8 broncho-alveolar lavage (BAL) samples from 8 iatrogenic subglottic tracheal stenosis patients, including 8 PSB samples from tracheal scar sites, 8 PSB samples from scar-free sites and 8 BAL samples, by lavaging the subsegmental bronchi of the right-middle lobe. Metagenomic sequencing was performed to characterize the microbiome profiling of 16 PSB and 8 BAL samples. Untargeted metabolomics was performed in 6 PSB samples (3 from tracheal scar PSB and 3 from tracheal scar-free PSB) using high-performance liquid chromatography‒mass spectrometry (LC‒MS).

RESULTS

At the species level, the top four bacterial species were Neisseria subflava, Streptococcus oralis, Capnocytophaga gingivals, and Haemophilus aegyptius. The alpha and beta diversity among tracheal scar PSB, scar-free PSB and BAL samples were compared, and no significant differences were found. Untargeted metabolomics was performed in 6 PSB samples using LC‒MS, and only one statistically significant metabolite, carnitine, was identified. Pathway enrichment analysis of carnitine revealed significant enrichment in fatty acid oxidation.

CONCLUSION

Our study found that carnitine levels in tracheal scar tissue were significantly lower than those in scar-free tissue, which might be a new target for the prevention and treatment of iatrogenic tracheal stenosis in the future.

Distribution and chemotactic mechanism of CD4+ T cells in traumatic tracheal stenosis

A systemic and local inflammatory immune imbalance is thought to be the cause of traumatic tracheal stenosis (TS). However, with CD4+ T lymphocytes being the predominant immune cells in TS, the mechanism of action and recruitment has not been described. In our research, using flow cytometry, ELISA, immunofluorescence, and Transwell chamber assays, the expression, distribution, and potential chemotactic function of CD4+ T cells in TS patients were examined before and after treatment. The results showed that the untreated group had significantly more CD4+ T cells and their secreted TGF-β1 than the treated group. Additionally, the untreated group's CD4+ T cells showed a significant rise in CCL22 and CCL1, as well as a larger proportion of CCR4 and CCR8. CD4+ T cells and CD68+ macrophages located in TS also expressed CCL1 and CCL22. In vitro, anti-CCL1 and anti-CCL22 can partially block the chemoattractant effect of TS bronchoalveolar lavage (BAL) on purified CD4+ T cells. The findings of this study indicated that TS contained unbalanced CD4 immune cells that were actively recruited locally by CCR4/CCL22 and CCR8/CCL1. As a result, it is anticipated that CD4 immune rebalancing can serve as a novel treatment for TS.

A Multi-armed Unfurling Actuator for Airway Lumen Measurement

Objective measurement of the lumen area demands an intraoperative diagnostic tool to aid on-site decision-making. We present a compliant mechanism-based unfurling actuator assembly integrated with a shaft connected to a motorized encoder to translate torque from the user at the proximal end to the actuator at the distal end. The actuator assembly has flexible arms coiled inside a cylindrical casing that moves radially outward upon actuation. Leveraging 3D printing of flexible materials, the unfurling actuator's four-arm design enables patency measurements in circumferential tracheal stenosis of varying grades. The rotary encoder output is correlated with the radially outward movement of the unfurling arms to estimate the lumen diameter. The measurement stability is analyzed using process control charts; data distribution over ten iterations reveals nearly 100% of process data falls between ±3 sigma (Upper and Lower control limits). Comparing measurements from the tool with direct measurement (vernier caliper) and ImageJ analysis, one-way ANOVA for circular morphology yields no significant differences in diameter p = 0.974 and area measurements p = 0.975.Clinical Relevance- Central airway narrowing reduces the effective lumen area in the tracheal and bronchial segments. Grading the degree of narrowing is often based on a suspicion index. A quick but thorough assessment of the airway caliber is essential in emergent or planned intubation, whether congenital, iatrogenic, or idiopathic tracheal stenosis.

Sufentanil target controlled infusion (TCI) versus remifentanil TCI for monitored anaesthesia care for patients with severe tracheal stenosis undergoing fiberoptic bronchoscopy: protocol for a prospective, randomised, controlled study

INTRODUCTION

The use of monitored anaesthesia care (MAC) is necessary and ubiquitous for fiberoptic bronchoscopy. Anaesthetic management of patients with severe tracheal stenosis has always been a challenge. The efficacy and safety of the MAC with sufentanil target controlled infusion (TCI) and remifentanil TCI in patients with severe tracheal stenosis are still unknown.

METHODS ANALYSIS

This study is a prospective, investigator-initiated, two-arm, randomised control trial to compare the efficacy and safety of sufentanil TCI with remifentanil TCI in patients with severe tracheal stenosis undergoing fiberoptic bronchoscopy. 270 patients will be randomly assigned to the sufentanil TCI group or remifentanil TCI group, with a 1:1 ratio in two groups. The primary outcome is the incidence of hypoxaemia (an oxygen saturation of <90%). The secondary outcome investigates the severity of hypoxaemia, cough severity, haemodynamic variables, sedation scores and satisfaction scores.

ETHICS AND DISSEMINATION

The study has been approved by the Medical Ethics Committee of Shanghai Pulmonary Hospital (approval No. K19-122). The results will be submitted for publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ChiCTR2100043380.

Antibacterial and antihyperplasia polylactic acid/silver nanoparticles nanofiber membrane-coated airway stent for tracheal stenosis

Antibacterial and antihyperplasia airway stents are highly desirable for tracheal stenosis. Herein, a series of polylactic acid (PLA) and silver nanoparticles (AgNPs) nanofiber membranes (PLA, PLA-4 %AgNPs and PLA-6 % AgNPs) were prepared by electrospinning. The physicochemical and biological properties of the resultant nanofiber membranes were examined. The SEM and drug release results indicated that the AgNPs were successfully introduced into PLA, and could be sustained to be released from membranes. The membranes showed antibacterial activity against S. aureus and P. aeruginosa, and cytocompatibility towards CCC-HPF-1 and NHBE cells. Furthermore, the membranes were used to cover a self-expandable metallic stent for use in the treatment of rabbit tracheal stenosis. The in vivo results revealed that the membranes, especially the AgNPs-coated airway stent could suppress tracheal stenosis by reducing inflammation and collagen deposition. Additionally, the study further confirmed that the inhibition of bacterial content in the trachea could be positively correlated with the reduction in tracheal granulation tissue hyperplasia. Conclusively, the PLA/AgNPs nanofiber membrane-coated airway stent has practical value for patients with clinical tracheal stenosis.

A new dimension of success in the management of airway disease in children with neurological deficit

OBJECTIVES

Anomalies of the larynx and trachea can cause respiratory distress in infants and older children. Depending on its nature, degree and extent of the disease invasive open surgery is indicated. Non-airway-related co-morbidities increase the challenges in its treatment. Neurological deficit poses a great challenge as it is associated with hypotonia and causes diminished laryngeal coordination. The definition of success in treatment of laryngotracheal disease has always focused on the post-operative functional outcomes: breathing, voice swallowing. The aim of this study is to describe a new dimension of success in the management of laryngotracheal disease in children with moderate neurological deficit, where the expected functional gain is less than in otherwise healthy children.

METHODS

This retrospective observational study includes all patients who have undergone open reconstructive airway surgery between 2012 and 2017. Control patients without neurological deficit and cases with moderate neurological deficit were included. Functional outcome data was obtained from clinical records and two questionnaires were filled in by the parents of the children: one the pediatric voice-handicap index (pVHI) and a quality of life questionnaire.

RESULTS

Thirty-two children were included of which ten had moderate neurological deficit. Both groups revealed post-operatively an improvement in the functional outcomes: breathing, voice and swallowing, however, as expected, a trend was observed towards less functional improvement in children with neurological deficit. Both groups reveal a remarkable gain in quality of life (QoL).

CONCLUSION

Indicating the QoL to be an unidentified, dimension of success in the management of laryngotracheal disease in children with moderate neurological deficit.

[Analysis of 2 cases of dyspnea happening after tracheotomy and the clinical application of Mimics 10.01]

Post-intubation tracheal stenosis was a late time complication after tracheotomy but the happening of dyspnea was unusual. Diagnosing tracheal stenosis after incubation, and figuring out the location and causes of the stenosis were important. Treatment of post-incubation tracheal stenosis relied on accurate diagnosis of the type of tracheal stenosis. Computed tomography (CT) and laryngoscope could be used for detecting the stenosis but not enough. Two patients who were already under the urgent tracheotomy over 1 year were reported. However apnea was found on these two patients for a long time after traheotomy. Obviously laryngeal obstruction appeared. CT virtual bronchoscope and laryngoscope examination showed that the cannula was obstructed and plenty of granulation tissue blocked the orificium. But the exact location of the cannula and the adjacent relationship of the tissue around the cannula was equivocal. Mimics 10.01 software was used to analyze the data of the CT scan and found that a pseudo cavity was formed by granulation tissue which partly blocked the cannula in 1 case; granulation tissue occupation and scar formation in the trachea were the reason of tracheal stenosis but not the collapse of the cartilage in case 2. The purpose of this report is to discuss the cause of dyspnea after emergency tracheotomy, its diagnostic method and their management. CT virtual bronchoscope and laryngoscope should be used as a regular examination after tracheotomy to clarify the location of cannula and avoid the failure of airway opening caused by the dislocation of cannula and the complication. Trachea tissue should be protected properly during and after the tracheotomy which might decline the rate of the tissue remodeling, tracheal stenosis and dyspnea after surgery. The clinical use of Mimics 10.01 made it possible to observe morphology more directly by invasive examination and provided a significant clue to make the operation plan so that it should be used widely. Meanwhile, the method to put the cannula into its right way under the guidance of rigid endoscope and the excision of granulation tissue by semiconductor laser should become one of the best treatments of this disease. Following the method above, laryngeal obstruction was relieved after the surgery. Postoperative follow-up lasted for 1 year and recurrence was not found.

[Airway Management for Partial Lung Lobectomy in a Patient with Subglottic Stenosis: A Case Report]

We report a case of sub-glottis stenosis encountered during anesthetic induction. A 79 year-old male was scheduled for a right partial lung lobectomy with video assisted thoracic surgery. Significant history includes percutaneous coronary intervention and pacemaker insertion for myocardial infarction, tuberculosis, trache- ostomy and radiation therapy for vocal cord cancer. Difficulty in tracheal intubation was predicted, but chest X-ray and CT scan did not show tracheal steno- sis. General anesthesia was induced smoothly and mask ventilation was easy. The vocal cord was fully exposed by McGRATH® MAC laryngoscope. However, inser- tion of double lumen tube (37 Fr) was impossible because of resistance just under the vocal cords. A membranous subglottic stenosis was found using a flexible bronchoscope. Then we inserted ID 7.0 mm single lumen tube and accomplished differential lung ventilation using a bronchial blocker. Surgery was done smoothly. In spite of recent advances in radiographic imaging, some cases of tracheal stenosis are difficult to diagnose.

[Assessment of congenital vascular rings with MDCT on children]

OBJECTIVE

To evaluate the value of MDCT on diagnosis of congenital vascular rings on children.

METHODS

Retrospective analysis on 43 cases of congenital vascular rings, which underwent MDCT during Oct 2008 to Dec 2014 in Beijing Anzhen hospital affiliated to capital medical university. 21 males, 22 females; age from 29 days to 8 years, mean age 1.46 years, 33 cases are not beyond 1 year. All the results were compared with that of the echocardiogram or record of the surgery. The CT data were read and reconstructed with multiplanar reconstruction (MPR), maximum intensity projection (MPR), minimum intensity projection (MinIP), volume rendering (VR). The image quality was evaluated and the diagnostic value and the standard diagnostic program were discussed.

RESULTS

Of 43 cases of vascular rings:there were 6 cases of pulmonary artery sling (13.95%), 9 cases of right aortic arch /aberrant left subclavian artery(20.93%), 18 cases of left aortic arch/aberrant right subclavian artery (41.86%), 10 cases of double aortic arch (23.26%). Forty cases (93.02%) were combined with other cardiovascular or pulmonary malformations. Every malformation was revealed clearly and proved by echocardiogram. Of 3 cases (6.98%) without any other malformation, 2 cases were combined tracheal stenosis. A pulmonary artery sling was proved by surgery; the other 2 cases were double aortic arch. All the images of 43 cases could be reconstructed well. MPR and VR showed the origin, shape, and whole course of vascular rings directly; MinIP and VR could display the shape, width and development of trachea, revealed the relationship between vascular rings, trachea and esophagus. It was important to show and measure the component vascular of the ring. Attention should be paid to the whole course of trachea and esophagus, especially those segments which were close to the ring vascular. The tracheal stenosis as well as intra-cardio anatomy malformations should be measured on MPR images if existed. According to the segmental analysis method, comes the overall final diagnosis. A standard diagnostic program on vascular ring was proposed.

CONCLUSION

MDCT axis images with various 3D post processing methods could reveal the compose of vascular rings and the relationship between vascular rings, trachea and esophagus.

[Balloon dilatation bronchoplasty in management of bronchial stenosis in children with mycoplasma pneumonia]

OBJECTIVE

To assess the efficacy and safety of balloon dilatation through flexible bronchoscopy in the management of inflammatory stenosis of grade 4-5 bronchus.

METHOD

Thirty patients with inflammatory bronchial stenosis caused by mycoplasmal pneumonia complicated with pulmonary atelectasis were treated with balloon dilatation through fiberoptic bronchoscopy. Before the procedure and after the last operation, therapeutic effect on pulmonary atelectasis were evaluated with CT and all of the patients were followed-up for 1 - 6 months.

RESULT

One to three operations were required to achieve satisfactory dilatation. After balloon dilatation, the average airway diameter increased obviously and the farther airways were opened after the therapy with irrigation. In 25 of 30 cases satisfactory immediate effects were obtained, a narrow airway diameter above expansion significantly increased as compared with preoperative diameter. In 5 children treated with balloon dilatation, the stenosis could not be improved significantly. In 3 patients with hyperplasia of granulation tissue, cryotherapy had to be applied. The operations were ineffective in the other two patients whose course of disease exceeded 3 months. After follow-up periods of 1 - 6 months, chest CT manifestation of expanded sites was improved in 28 patients and atelectasis disappeared. No severe complication was found in any patients.

CONCLUSION

Bronchoplasty by balloon dilatation through flexible fiberoptic bronchoscopy is a simple, effective and safe method to treat childhood tracheobronchial stenosis after pulmonary infections.

[Clinical features and treatment of closed rupture of cervical trachea]

OBJECTIVE

To study the clinical manifestations and treatments of closed injuries of the cervical trachea.

METHOD

We carried out a retrospective study of the clinical manifestations, diagnosis and treatment of patients with closed injuries of the cervical trachea that have been treated in our hospital over the last ten years. We analyzed commonly occurring clinical problems, key points of surgical treatment, and postoperative recovery. Fourty-one patients with acute closed injuries of the cervical trachea underwent emergency tracheotomy or anesthesia orotracheal intubation and surgical repair of the trachea within 24 to 48 hours. Twenty six patients had their tracheotomy tubes extubated after surgery and had their anesthesia orotracheal tubes extubated within 48 hours postoperatively; tracheotomy tubes remained in the airway in 15 patients postoperatively, and of them, 12 had extubation successfully in 2 weeks postoperatively, while the remaining 3 were left intubated due to laryngotracheal stenosis. Among the 3, 2 underwent further surgical repair and recovery, and 1 had a stent inserted.

RESULT

Twenty-eight patients fully recovered postoperatively. Ten patients mostly recovered postoperatively exception for hoarseness, and their fundamental phonation function recovered within 2 to 3 months but with poor movement of the vocal cords. The breathing and swallowing function of the other 3 patients recovered after the surgery, but they suffer from hoarseness.

CONCLUSION

In the treatment of closed disruption of the cervical trachea, prompt diagnosis and timely surgical repair of the structure and function of the trachea are key to saving the patients' lives and avoiding tracheal stenoses.

Quantifying the Physiology of Laryngotracheal Stenosis: Changes in Pulmonary Dynamics in Response to Graded Extrathoracic Resistive Loading

OBJECTIVES/HYPOTHESIS

A model of airway obstruction was developed to study the impact of changes in airway resistance on ventilatory mechanics. This was used to derive quantitative indices of airway obstruction to aid in the objective diagnosis and physiological monitoring of adult patients with laryngotracheal stenosis (LTS).

METHODS

Six airway resistors, the characteristics of which mirrored the selective impediment to inspiratory airflow that occurs in patients with LTS, were created and calibrated. Maximum-effort flow-volume loops were obtained from 15 volunteers with resistors placed in series with the spirometer. Diagnostic and monitoring performances of various flow-volume indices were assessed with receiver-operating characteristics (ROC) and analysis of variance (ANOVA), respectively. Promising indices were further evaluated in patients with LTS.

RESULTS

Experimentally, the ratio of expiratory and inspiratory flows at midvital capacity (MEF50/MIF50) and peak expiratory to inspiratory flow ratio (PEF/PIF) had diagnostic sensitivities of 87% and 89%, respectively. The best index, both experimentally and clinically, was the ratio of area under the expiratory and inspiratory curves (ratio of integrals), with experimental and clinical sensitivities of 97% and 100%, respectively. A clinical specificity of 95%, and area under the curve of 0.965 were achieved for this index. Both PEF/PIF and the ratio of integrals could identify step changes in airway resistance greater than 10 cmH2O . sec . L (P < .05; ANOVA).

CONCLUSIONS

Flow-volume testing is simple and noninvasive and can be used to quantify the diagnosis and physiological monitoring of patients with LTS. The ratio of areas under the expiratory and inspiratory curves appears to be the optimal index for this purpose.

Sequential alterations of tracheal mechanical properties in the neonatal lamb: effect of mechanical ventilation

Alterations in neonatal airway mechanics resulting from ventilatory therapies are implicated in airway collapse and chronic disease. Quantifying the functional impact of mechanical ventilation (MV) on the neonatal airway and elucidating the time course of these changes will support development of protective therapies. The objective of this study was to test the hypothesis that conventional MV would result in decreased static and dynamic elastance of an isolated tracheal segment and thinning of the muscle (trachealis) region of the tracheal wall in a time dependent manner. Tracheal segments were isolated in newborn lambs spontaneously breathing through the distal trachea; segments were MV (n = 7; PIP/PEEP = 35/5 cmH2O; 40 breaths/min) or instrumented, non-ventilated (SHAM; n = 7; PIP/PEEP = 0/0 cmH2O) for 4 hr. At baseline and hourly, tracheal segments were filled with saline, and static pressure-volume curves were constructed as the pressure response to stepwise volume infusions. Then, cross-sectional ultrasound images were captured at 0 cmH2O on SHAM, and at 0 cmH2O, peak inspiratory pressure (PIP) and positive end expiratory pressure (PEEP), on MV tracheae for subsequent dimensional analysis. Tracheal elasticity indices were derived from static pressure-volume data, and during dynamic ventilation using ultrasound images to calculate the stress-strain relationships. Over 4 hr of MV, tracheal internal diameter (ID) increased (14%; P < 0.05). Markers of tracheal mechanical properties indicated a decrease in elasticity under both static (bulk modulus; 28%; P < 0.05) and dynamic (elastic modulus; 282 %; P < 0.05) conditions, indicating a significant alteration in elastic components. No time dependent changes were identified in dimensions or mechanical properties in the SHAM group.

CONCLUSIONS

MV results in dimensional alterations that increased anatomical dead space and reduced static and dynamic elastance of the neonatal trachea.

Prenatal glucocorticoids and exogenous surfactant therapy improve respiratory function in lambs with severe diaphragmatic hernia following fetal tracheal occlusion

Fetal tracheal occlusion (TO) accelerates lung growth and can reverse severe lung hypoplasia associated with diaphragmatic hernia (DH), however, lung compliance (Cl) and respiratory gas exchange remain abnormal. We determined the individual and combined effects of prenatal glucocorticoids (GC) and exogenous surfactant therapy (S) on postnatal pulmonary function in lambs with DH that underwent prolonged TO. DH was created in 22 fetal sheep at 65 d of gestation and TO performed at 110 d. Eleven DH/TO animals received prenatal GC (betamethasone, 0.5 mg/kg) 48 h before delivery; six GC-treated and five non-GC lambs were administered surfactant (Infasurf, 3 mg/kg) at birth. Six sham-operated lambs served as controls. Lambs were delivered at 139 d gestation and ventilated for 2 h. GC or surfactant therapy alone significantly improved respiratory gas exchange, Cl, and ventilatory efficiency index. Total lung capacity was normalized only in DH/TO lambs that received both GC and S.

[Laryngeal mask application for a case of unpredictable adult tracheal stenosis]

A 69-year-old man with chronic renal failure was scheduled for artero-venous shunt surgery for sustained hemodialysis. On the pre-anesthesia interview, the patient complained of no respiratory symptom. Chest x-ray showed some tracheal deviation. There was no past history of the respiratory system such as bronchitis, bronchial asthma, tumor, trauma or previous tracheal intubation. General anesthesia was induced smoothly with thiopental and suxamethonium. Face mask ventilation could be done easily. The vocal cord was exposed fully by standard McIntosh laryngoscope. However, a neither ID 7.5 nor 6.5 mm tracheal tube could be inserted into the trachea. Then, a size 4.0 laryngeal mask airway (LMA) was inserted smoothly and ventilation was maintained adequately. The surgery was done smoothly. Seven days after, bronchofiber scopic findings showed tracheal stenosis. The cause was unknown but not from inflammation or tumor. The patient complained no respiratory distress after the surgery. In such unpredictable tracheal stenosis with easy mask ventilation, LMA is a considerable option for respiratory management.

[Dilatation of tracheal stenosis with esophageal balloon dilator]

The solve of tracheal stenosis is problem which occupied a big number of experts. In this article was reported a case in which the problem of tracheal stenosis was solved by balloon dilatator which was used in a treatment of esophageal stenosis. We are thinking that esophageal balloon dilatation of trachela stenosis would be a one of the first steps in the problem solving.

Airway management in mucopolysaccharide storage disorders

Mucopolysaccharidoses (MPS), a group of disorders caused by a genetic disruption, create a special challenge for the otolaryngologist. With the rare types of MPS IV and MPS 1 S, a skilled practitioner is required to abate airway management complications. The erratic deposits of mucopolysaccharides throughout the trachea should be taken into account when decisions to stent the airway are made. Proper management requires to provide an airway that is custom-made to meet the patient's needs. This is a case-by-case presentation of 3 patients with MPS who presented to the Children's Hospital of Michigan with progressive respiratory embarrassment. Discussed are the various issues revolving around our ability to provide proper airway management, from intubation to tracheostomy tube placement.

Use of a Fogarty catheter as a bronchial blocker through a single-lumen endotracheal tube in patients with subglottic stenosis

One-lung ventilation can be achieved with a double-lumen tube or a bronchial blocker. However, the larger outer diameters of double-lumen or Univent tubes may prevent their passage through an area of subglottic stenosiss. We present five cases of subglottic stenosis in which a Fogarty catheter was used as a bronchial blocker through a single-lumen endotracheal tube. The outer diameters of a double-lumen tube, Univent tube and single-lumen tube were compared. Despite special equipment designed for one-lung ventilation, the use of a bronchial blocker through a single-lumen tube, which has the thinnest available wall thickness, seems to be one of the most effective and safest ways of achieving one-lung ventilation in patients with subglottic stenosis or narrowing.

Voice prostheses: long-term follow-up retrospective study (three- to sixteen-year follow-up of 22 patients)

BACKGROUND

Thirty-five patients using tracheoesophageal voice with a 3- to 16-year follow-up were investigated. We analyzed functional voice outcome, voice prosthesis (VP) lifespan, and VP-related complications.

METHODS

Between 1987 and 2001, 81 patients underwent total laryngectomy (TL). The 35 currently surviving patients (31 men, 4 women) were studied for VP lifespan and VP-related complications encountered up to 16 years after surgery. For voice rehabilitation, the 35 laryngectomies of our study required 178 prostheses. Short- and long-term voice results of 22 patients were compared by objective voice examination: maximum phonation time (MPT), intensity range (Int.), fundamental frequency (F0), frequency analysis (FA), and voice handicap index (VHI).

RESULTS

Long-term results are: F0=131 (range: 30-250); Int=22.5 dB (range: 17-35 dB); MPT=4 sec (range: 2-12 sec); FA=3 (range: 1-4); VHI=38/120 (range: 8-73). Short- vs long-term outcome comparison shows the following values: F0: 93 vs 135 Hz; Int: 25 vs 24 dB; FA: 1 vs 3; and MPT: 21 vs 4 sec. The mean VP lifespan is 165.5 days for Provox (range: 2 days-30 months); 143.5 days for Blom-Singer (range: 10 days-24 months); and 195 days for VoiceMaster (6-7 months). Postoperative complications involved 12 cases of periprosthetic leakage (6.74%); 31 granulomas (17.4%); 3 partial stenoses of the tracheoesophageal tract (1.6%); and 1 temporarily removed VP (0.5%).

CONCLUSIONS

Complications are generally resolved during standard office-setting examination. The commercially available VPs are complementary, used according to the diverse characteristics of each VP.

Cervical spine involvement in Larsen's syndrome: a case illustration

We present the progressive clinical course of a child with myelopathy attributable to cervical spine abnormalities associated with Larsen's syndrome. After anterior and posterior cervical fusion, his preoperative symptoms of weakness, gait dysfunction, and hyperreflexia have improved at 9-month follow-up. The progressive course and importance of early referral and intervention should be of interest to the general pediatric community.

A simple and secure technique for tracheal T-tube insertion

We describe a simple and secure technique for the insertion of a long Montgomery type T-tube in patients with tracheal stenosis. An endotracheal tube is placed into the lumen of the T-tube and by maintaining the airway during insertion, the technique has been found to be safe and it can prevent the kind of tracheal damage occurring with blind techniques.

Progressive laryngotracheal stenosis with short stature and arthropathy

Laryngotracheal stenosis is rare in adults, especially in the absence of a malignancy. It is most commonly caused by fibrosis following endotracheal intubation or tracheal trauma. Other conditions causing progressive airway narrowing include the mucopolysaccharidoses and autoimmune disorders. With the exception of storage diseases, there are no well-defined genetic disorders with progressive airway narrowing as a common complication. We have evaluated three unrelated individuals with this potentially life-threatening finding, all of whom have a previously unrecognized condition. Each patient had short stature and joint stiffness with no evidence for infectious, inflammatory, or metabolic diseases as a cause of their condition. None of our patients had clinical findings indicative of known skeletal dysplasias or storage diseases. They had minor facial anomalies which included deeply set eyes, bushy eyebrows, and flat midface. Given the unique findings of our patients including adult onset critical tracheal stenosis, short stature, progressive joint limitation, and distinct facial anomalies, we conclude that they have a previously undescribed condition.

[A newly devised endotracheal tube for patients with narrowed trachea]

A 27 year old female patient with pulmonary adenoid cystic cancer was planned for emergency tracheotomy for hemoptysis and severe dyspnea. Six month previously she had a silicon tube (5.5 mm-ID, 40 mm in length) placed in her trachea, because of severe tracheal stenosis. Airway management by endotracheal intubation was deemed necessary during the tracheotomy. However, because of her tracheal narrowing, it was not possible to insert a usual endotracheal tube for adult. First, we made a 4.0 mm-ID endotracheal tube without cuff 12 cm in length (TUBE 1), and a 5.5 mm-ID tube 18 cm in length (TUBE 2). We inserted the TUBE 1 into the TUBE 2, and glued them with Aron-Alpha, making it 25 cm long. We could perform tracheotomy by intubating and wedging this tube into silicon tube.

Research in pediatric otolaryngology: an overview

Pediatric otolaryngology research, most of the time, relies on basic research in animals. This is especially evident when looking at the neonatal period on which this paper is mainly focused. Most of perinatal hearing pathologies are related to the existence of sensitive periods during development. Major improvements of evoked potential techniques have permitted early recognition of hearing losses. This paper also deals with problems involving secretory otitis media, laryngeal stenosis and drooling in crippled children. Finally, there is brief mention of future research domains: immunology and vestibular pathology.

Microsurgical reconstruction of the trachea in rats (an experimental study)

This study was carried out to evaluate the use of 'Zenoderm' (enzyme treated procine dermis) as a patch for the repair of tracheal defects in rats, with particular reference to its application in the treatment of some cases of tracheal stenosis. Fifty-three rats were included in the study. Using microsurgical techniques, a defect was created in the cervical trachea and repaired using a suitable patch of 'Zenoderm' (two groups with different sized defects). In a further group of rats, healing of the trachea was studied after excision of a segment and end to end anastomosis. A set number of rats were sacrificed after intervals of 14, 28, 91 and 182 days when the trachea was excised and evaluated. Healing of the tracheae following end to end anastomosis was satisfactory in all cases with no evidence of stenosis. The two groups of tracheae with Zenoderm patches showed progressive stenosis at the area of the repair but there was no evidence of respiratory obstruction or distress. The Zenoderm patch and the regenerating epithelium were both evaluated by light microscopy and scanning electromicroscopy. The Zenoderm patch showed gradual absorption and was replaced by host collagen. There was gradual regeneration of epithelium which showed slow maturation from flat non-ciliated epithelium to partially cuboidal and columnar epithelium with some cilia showing early differentiation to respiratory epithelium. In conclusion, this experimental study confirmed the biocompatibility of 'Zenoderm' in rats. It provided a suitable surface for regeneration of tracheal epithelium. Replacement of the patch by the host collagen is promising but requires further study to assess its rigidity and ability to withstand pressure changes in the trachea.

Tracheal compression by the innominate artery in infancy and childhood

The authors evaluated the normal radiographic anatomy of the innominate (brachiocephalic) artery in children. Review of 1,000 randomly selected lateral chest radiographs demonstrated anterior tracheal indentation in 30% of the children under the age of 2 years. In addition, 172 angiograms in children with congenital heart disease revealed that the innominate artery normally originates either completely or partially to the left of the trachea and crosses in front of it.