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1.  Surgical Management of Tracheal Compression Caused by Mediastinal Goiter: Is Extracorporeal Circulation Requisite? 
Journal of Thoracic Disease  2009;1(1):48-50.
Objective
To investigate the surgical and anesthetic management strategy of tracheal compression caused by mediastinal goiter.
Methods
We retrospectively analyzed a patient with an anterior mediastinal mass in whom cardiopulmonary bypass was kept on standby via femoral vessels before induction of anesthesia. Bronchoscope guided tracheal intubation was done and tumor was removed via a cervical approach. Relative literature was reviewed.
Results
CPB via femoral vessels before induction of anesthesia help the patient recover from the perioperative period safely. While bronchoscope slipped beyond the obstruction smoothly and spent less time. The apparently narrow trachea easily distended and did not impair passage of the tube into the trachea opposed to being predicted preoperatively. The histopathological diagnosis confirmed the tumor as a nodular goiter with the formation of hematoma.
Conclusions
CPB via femoral vessels before induction of anesthesia during surgical management of tracheal compression caused by mediastinal goiter is justified while bronchoscope guided tracheal intubation to establish the tracheal patency is a safe and feasible alternative.
PMCID: PMC3256485  PMID: 22263003
mediastinal tumor; substernal goiter; tracheal compression; extracorporeal circulation
2.  Successful esophageal bypass surgery in a patient with a large tracheoesophageal fistula following endotracheal stenting and chemoradiotherapy for advanced esophageal cancer: case report 
Esophagus  2012;10(1):27-29.
A 63-year-old man with esophageal achalasia for more than 20 years complained of respiratory distress. He was admitted as an emergency to the referral hospital three months previously. Computed tomography revealed tracheobronchial stenosis due to advanced esophageal cancer with tracheal invasion. He underwent tracheobronchial stenting and chemoradiotherapy. A large tracheoesophageal fistula (TEF) developed after irradiation (18 Gy) and chemotherapy, and he was unable to eat. Thereafter, he was referred to our hospital, where we performed esophageal bypass surgery using a gastric conduit. A percutaneous cardiopulmonary support system was prepared due to the risk of airway obstruction during anesthesia. A small-diameter tracheal tube inserted into the stent achieved ordinary respiratory management. No anesthesia-related problems were encountered. Oral intake commenced on postoperative day 9. He was discharged on postoperative day 23 and was able to take in sustenance orally right up to the last moment of his life. Esophageal bypass under general anesthesia can be performed in patients with large TEF with sufficient preparation for anesthetic management.
doi:10.1007/s10388-012-0338-4
PMCID: PMC3589656  PMID: 23482402
Tracheoesophageal fistula; Esophageal bypass; Tracheobronchial stent
3.  Anesthesia for massive retrosternal goiter with severe intrathoracic tracheal narrowing: the challenges imposed -A case report- 
Korean Journal of Anesthesiology  2012;62(5):474-478.
Anesthetic management of patients with mediastinal masses remains challenging as acute cardiorespiratory decompensation may follow induction of anesthesia. We describe a 57 year old lady with massive retrosternal goiter and severe intrathoracic tracheal compression who had a total thyroidectomy. Comprehensive contingency plans were an essential prerequisite for successful management of difficult airway, including multidisciplinary involvement of otorhinolaryngologic and cardiothoracic surgeons preparing for rigid bronchoscopy and cardiopulmonary bypass. Awake oral fiberoptic intubation was performed under dexmedetomidine sedation. Severe tracheal narrowing necessitated usage of a 5.0 mm uncuffed flexometallic endotracheal tube. Anesthesia was maintained with sevoflurane and dexmedetomidine infusion with target controlled infusion of remifentanil as analgesia. No muscle relaxant was given. Surgical manipulation led to intermittent total tracheal compression and inadequate ventilation. The tumor was successfully removed via the cervical approach. A close working relationship between anesthesiologists and surgeons was the key to the safe use of anesthesia and uneventful recovery of this patient.
doi:10.4097/kjae.2012.62.5.474
PMCID: PMC3366316  PMID: 22679546
Awake fiberoptic intubation; Dexmedetomidine; Difficult airway; Mediastinal mass
4.  Severe airway obstruction in an infant with congenital tracheal stenosis and congenital heart disease -A case report- 
Korean Journal of Anesthesiology  2012;62(3):285-288.
Congenital tracheal stenosis (CTS), though rare, is important because the mortality and morbidity rates are high in infants. Especially, associated congenital heart disease (CHD) in these infants may compound the effects of airway pathology. A 3-week-old patient with long-segmental tracheal stenosis below an anomalous right-upper lobe (RUL) bronchus had undergone a total correction of double outlet right ventricle. On third postoperative day, hypercarbia developed, and severe airway obstruction and atelectasis were detected. An emergency slide tracheoplasty was performed under cardiopulmonary bypass (CPB). The patient recovered well after the surgery. Thus, special attention needs to be paid during the postoperative intensive care of patients with congenital tracheal anomalies. Early detection and prompt diagnosis of airway obstruction can help reduce the morbidity and mortality rates. Further, it is important to select the suitable treatment of CTS associated with CHD.
doi:10.4097/kjae.2012.62.3.285
PMCID: PMC3315662  PMID: 22474559
Airway obstruction; Congenital; Heart disease; Tracheal stenosis
5.  Emergency management of a patient with severe airway obstruction resulting from poorly differentiated thyroid carcinoma: A case report 
Oncology Letters  2012;4(4):771-774.
We present a case of a life-threatening almost complete airway obstruction resulting from poorly differentiated thyroid carcinoma in a 48-year-old male. Airway obstruction may lead to unexpected mortality by suffocation and patients with poorly differentiated thyroid carcinoma usually have a fast deterioration and fatal outcome. In the case presented, we describe a safe and effective treatment strategy. Assisted by femoro-femoral cardiopulmonary bypass oxygenation, a tracheal stent was implanted successfully. Following surgery there were no complications, and chemoradiotherapy resulted in the relief of obstructing symptoms and improved the quality of life of the patient. This case indicates that femoro-femoral cardiopulmonary bypass provides adequate oxygen support to undergo further management and that tracheal stent implant is an effective emergent measure to relieve severe airway obstruction in patients with poorly differentiated thyroid carcinoma.
doi:10.3892/ol.2012.827
PMCID: PMC3506704  PMID: 23226791
thyroid cancer; airway obstruction; cardiopulmonary bypass; stents
6.  Surgical treatment of postintubation tracheal stenosis: Iranian experience of effect of previous tracheostomy 
Background
Postintubation tracheal stenosis remains the most common indication for tracheal surgery. In the event of a rapid and progressive course of the disease after extubation, surgical approaches such as primary resection and anastomosis or various methods of tracheoplasty should be selected. We report our experience with surgical management of moderate to severe postintubation tracheal stenosis. We also compared intraoperative variables in postintubation tracheal stenosis between those with and without previous tracheostomy.
Methods
Over a 5-year period from June 2005 to July 2010, 50 patients aged 14–64 years with moderate (50%–70% of the lumen) to severe (>70%) postintubation tracheal stenosis underwent resection and primary anastomosis. Patients were followed up to assess the surgical outcome. To study the effect of previous tracheostomy on treatment, surgical variables were compared between patients with previous tracheostomy (group A, n = 27) and those without previous tracheostomy (group B, n = 23).
Results
Resection and primary anastomosis was performed via either cervical incision (45 patients) or right thoracotomy (five patients). In two patients with subglottic stenosis, complete resection of the tracheal lesion and anterior portion of cricoid cartilage was performed, and the remaining trachea was anastomosed to the thyroid cartilage using a Montgomery T-tube. There was only one perioperative death in a patient with a tracheo-innominate fistula. The length of the resected segment, number of resected rings, and subsequent duration of surgery were significantly greater in group A compared with group B (P < 0.05). Six months after surgery, the outcome was satisfactory to excellent in 47 (95.9%) patients.
Conclusion
This surgical approach leads to highly successful results in the treatment of moderate to severe postintubation tracheal stenosis. In addition, previous tracheostomy might prolong the duration of surgery and increase the need for postoperative interventions due to an increase in the length and number of resected tracheal segments. Therefore, in the event of emergency tracheostomy in postintubation tracheal stenosis, insertion of the tracheostomy tube close to the stenotic segment is recommended.
doi:10.2147/IJGM.S27559
PMCID: PMC3273371  PMID: 22319246
trachea; tracheostomy; tracheal stenosis; intubation; tracheal resection
7.  Microbubbles detection during cardiopulmonary bypass with transoesophageal echocardiography: a case report 
Cases Journal  2008;1:141.
Introduction
Microembolic signals are usually detected with transcranial doppler during cardiac surgery.
This report focuses on suggesting the transesophageal echocardiography as a different diagnostic approach to detect microemboli during cardiopulmonary bypass.
Case presentation
A 58 year old male patient, caucasian race, was operated on video assisted minimally invasive mitral valve repair using right minithoracotomy approach. His past medical history included an uncontrolled hypertension, dyslipidemia, insulin dependent diabetes mellitus, carotid arteries stenosis. The extracorporeal circulation was performed with femoral-femoral artery and venous approach. Negative pressure for vacuum assist venous drainage was applied in order to facilitate venous blood return. The patient had a brain monitoring with bilateral transcranial doppler of middle cerebral arteries and a double channels electroencephalogram. A three dimensional transesophageal echocardiography to evaluate the mitral valve repair was performed.
During the cardiopulmonary bypass a significant microembolic activity was detected in the middle cerebral arteries spectrum velocities due to gas embolism from venous return. Simultaneous recording of microbubbles was also observed on the descending thoracic aorta transesophageal echo views.
Conclusion
During the aortic cross-clamping time the transesophageal echocardiography can be useful as an alternative method to assess the amount of gas embolism coming from cardiopulmonary bypass. These informations can promote immediate interaction between perfusionist, surgeon and anesthesiologist to perform adequate manoeuvres in order to reduce the microembolism during extracorporeal circulation.
doi:10.1186/1757-1626-1-141
PMCID: PMC2542348  PMID: 18775067
8.  Extracorporeal Lung Support Technologies – Bridge to Recovery and Bridge to Lung Transplantation in Adult Patients 
Executive Summary
For cases of acute respiratory distress syndrome (ARDS) and progressive chronic respiratory failure, the first choice or treatment is mechanical ventilation. For decades, this method has been used to support critically ill patients in respiratory failure. Despite its life-saving potential, however, several experimental and clinical studies have suggested that ventilator-induced lung injury can adversely affect the lungs and patient outcomes. Current opinion is that by reducing the pressure and volume of gas delivered to the lungs during mechanical ventilation, the stress applied to the lungs is eased, enabling them to rest and recover. In addition, mechanical ventilation may fail to provide adequate gas exchange, thus patients may suffer from severe hypoxia and hypercapnea. For these reasons, extracorporeal lung support technologies may play an important role in the clinical management of patients with lung failure, allowing not only the transfer of oxygen and carbon dioxide (CO2) but also buying the lungs the time needed to rest and heal.
Objective
The objective of this analysis was to assess the effectiveness, safety, and cost-effectiveness of extracorporeal lung support technologies in the improvement of pulmonary gas exchange and the survival of adult patients with acute pulmonary failure and those with end-stage chronic progressive lung disease as a bridge to lung transplantation (LTx). The application of these technologies in primary graft dysfunction (PGD) after LTx is beyond the scope of this review and is not discussed.
Clinical Applications of Extracorporeal Lung Support
Extracorporeal lung support technologies [i.e., Interventional Lung Assist (ILA) and extracorporeal membrane oxygenation (ECMO)] have been advocated for use in the treatment of patients with respiratory failure. These techniques do not treat the underlying lung condition; rather, they improve gas exchange while enabling the implantation of a protective ventilation strategy to prevent further damage to the lung tissues imposed by the ventilator. As such, extracorporeal lung support technologies have been used in three major lung failure case types:
As a bridge to recovery in acute lung failure – for patients with injured or diseased lungs to give their lungs time to heal and regain normal physiologic function.
As a bridge to LTx – for patients with irreversible end stage lung disease requiring LTx.
As a bridge to recovery after LTx – used as lung support for patients with PGD or severe hypoxemia.
Ex-Vivo Lung Perfusion and Assessment
Recently, the evaluation and reconditioning of donor lungs ex-vivo has been introduced into clinical practice as a method of improving the rate of donor lung utilization. Generally, about 15% to 20% of donor lungs are suitable for LTx, but these figures may increase with the use of ex-vivo lung perfusion. The ex-vivo evaluation and reconditioning of donor lungs is currently performed at the Toronto General Hospital (TGH) and preliminary results have been encouraging (Personal communication, clinical expert, December 17, 2009). If its effectiveness is confirmed, the use of the technique could lead to further expansion of donor organ pools and improvements in post-LTx outcomes.
Extracorporeal Lung support Technologies
ECMO
The ECMO system consists of a centrifugal pump, a membrane oxygenator, inlet and outlet cannulas, and tubing. The exchange of oxygen and CO2 then takes place in the oxygenator, which delivers the reoxygenated blood back into one of the patient’s veins or arteries. Additional ports may be added for haemodialysis or ultrafiltration.
Two different techniques may be used to introduce ECMO: venoarterial and venovenous. In the venoarterial technique, cannulation is through either the femoral artery and the femoral vein, or through the carotid artery and the internal jugular vein. In the venovenous technique cannulation is through both femoral veins or a femoral vein and internal jugular vein; one cannula acts as inflow or arterial line, and the other as an outflow or venous line. Venovenous ECMO will not provide adequate support if a patient has pulmonary hypertension or right heart failure. Problems associated with cannulation during the procedure include bleeding around the cannulation site and limb ischemia distal to the cannulation site.
ILA
Interventional Lung Assist (ILA) is used to remove excess CO2 from the blood of patients in respiratory failure. The system is characterized by a novel, low-resistance gas exchange device with a diffusion membrane composed of polymethylpentene (PMP) fibres. These fibres are woven into a complex configuration that maximizes the exchange of oxygen and CO2 by simple diffusion. The system is also designed to operate without the help of an external pump, though one can be added if higher blood flow is required. The device is then applied across an arteriovenous shunt between the femoral artery and femoral vein. Depending on the size of the arterial cannula used and the mean systemic arterial pressure, a blood flow of up to 2.5 L/min can be achieved (up to 5.5 L/min with an external pump). The cannulation is performed after intravenous administration of heparin.
Recently, the first commercially available extracorporeal membrane ventilator (NovaLung GmbH, Hechingen, Germany) was approved for clinical use by Health Canada for patients in respiratory failure. The system has been used in more than 2,000 patients with various indications in Europe, and was used for the first time in North America at the Toronto General Hospital in 2006.
Evidence-Based Analysis
The research questions addressed in this report are:
Does ILA/ECMO facilitate gas exchange in the lungs of patients with severe respiratory failure?
Does ILA/ECMO improve the survival rate of patients with respiratory failure caused by a range of underlying conditions including patients awaiting LTx?
What are the possible serious adverse events associated with ILA/ECMO therapy?
To address these questions, a systematic literature search was performed on September 28, 2009 using OVID MEDLINE, MEDLINE In-Process and Other Non-Indexed Citations, EMBASE, the Cumulative Index to Nursing & Allied Health Literature (CINAHL), the Cochrane Library, and the International Agency for Health Technology Assessment (INAHTA) for studies published from January 1, 2005 to September 28, 2008. Abstracts were reviewed by a single reviewer and, for those studies meeting the eligibility criteria, full-text articles were obtained. Reference lists were also examined for any additional relevant studies not identified through the search. Articles with an unknown eligibility were reviewed with a second clinical epidemiologist and then a group of epidemiologists until consensus was established.
Inclusion Criteria
Studies in which ILA/ECMO was used as a bridge to recovery or bridge to LTx
Studies containing information relevant to the effectiveness and safety of the procedure
Studies including at least five patients
Exclusion Criteria
Studies reporting the use of ILA/ECMO for inter-hospital transfers of critically ill patients
Studies reporting the use of ILA/ECMO in patients during or after LTx
Animal or laboratory studies
Case reports
Outcomes of Interest
Reduction in partial pressure of CO2
Correction of respiratory acidosis
Improvement in partial pressure of oxygen
Improvement in patient survival
Frequency and severity of adverse events
The search yielded 107 citations in Medline and 107 citations in EMBASE. After reviewing the information provided in the titles and abstracts, eight citations were found to meet the study inclusion criteria. One study was then excluded because of an overlap in the study population with a previous study. Reference checking did not produce any additional studies for inclusion. Seven case series studies, all conducted in Germany, were thus included in this review (see Table 1).
Also included is the recently published CESAR trial, a multicentre RCT in the UK in which ECMO was compared with conventional intensive care management. The results of the CESAR trial were published when this review was initiated. In the absence of any other recent RCT on ECMO, the results of this trial were considered for this assessment and no further searches were conducted. A literature search was then conducted for application of ECMO as bridge to LTx patients (January, 1, 2005 to current). A total of 127 citations on this topic were identified and reviewed but none were found to have examined the use of ECMO as bridge to LTx.
Quality of Evidence
To grade the quality of evidence, the grading system formulated by the GRADE working group and adopted by MAS was applied. The GRADE system classifies the quality of a body of evidence as high, moderate, low, or very low according to four key elements: study design, study quality, consistency across studies, and directness.
Results
Trials on ILA
Of the seven studies identified, six involved patients with ARDS caused by a range of underlying conditions; the seventh included only patients awaiting LTx. All studies reported the rate of gas exchange and respiratory mechanics before ILA and for up to 7 days of ILA therapy. Four studies reported the means and standard deviations of blood gas transfer and arterial blood pH, which were used for meta-analysis.
Fischer et al. reported their first experience on the use of ILA as a bridge to LTx. In their study, 12 patients at high urgency status for LTx, who also had severe ventilation refractory hypercapnea and respiratory acidosis, were connected to ILA prior to LTx. Seven patients had a systemic infection or sepsis prior to ILA insertion. Six hours after initiation of ILA, the partial pressure of CO2 in arterial blood significantly decreased (P < .05) and arterial blood pH significantly improved (P < .05) and remained stable for one week (last time point reported). The partial pressure of oxygen in arterial blood improved from 71 mmHg to 83 mmHg 6 hours after insertion of ILA. The ratio of PaO2/FiO2 improved from 135 at baseline to 168 at 24 hours after insertion of ILA but returned to baseline values in the following week.
Trials on ECMO
The UK-based CESAR trial was conducted to assess the effectiveness and cost of ECMO therapy for severe, acute respiratory failure. The trial protocol were published in 2006 and details of the methods used for the economic evaluation were published in 2008. The study itself was a pragmatic trial (similar to a UK trial of neonatal ECMO), in which best standard practice was compared with an ECMO protocol. The trial involved 180 patients with acute but potentially reversible respiratory failure, with each also having a Murray score of ≥ 3.0 or uncompensated hypercapnea at a pH of < 7.2. Enrolled patients were randomized in a 1:1 ratio to receive either conventional ventilation treatment or ECMO while on ventilator. Conventional management included intermittent positive pressure ventilation, high frequency oscillatory ventilation, or both. As a pragmatic trial, a specific management protocol was not followed; rather the treatment centres were advised to follow a low volume low pressure ventilation strategy. A tidal volume of 4 to 8 mL/kg body weight and a plateau pressure of < 30 cm H2O were recommended.
Conclusions
ILA
Bridge to recovery
No RCTs or observational studies compared ILA to other treatment modalities.
Case series have shown that ILA therapy results in significant CO2 removal from arterial blood and correction of respiratory acidosis, as well as an improvement in oxygen transfer.
ILA therapy enabled a lowering of respiratory settings to protect the lungs without causing a negative impact on arterial blood CO2 and arterial blood pH.
The impact of ILA on patient long-term survival cannot be determined through the studies reviewed.
In-hospital mortality across studies ranged from 20% to 65%.
Ischemic complications were the most frequent adverse events following ILA therapy.
Leg amputation is a rare but possible outcome of ILA therapy, having occurred in about 0.9% of patients in these case series. New techniques involving the insertion of additional cannula into the femoral artery to perfuse the leg may lower this rate.
Bridge to LTx
The results of one case series (n=12) showed that ILA effectively removes CO2 from arterial blood and corrects respiratory acidosis in patients with ventilation refractory hypercapnea awaiting a LTx
Eight of the 12 patients (67%) awaiting a LTx were successfully transplanted and one-year survival for those transplanted was 80%
Since all studies are case series, the grade of the evidence for these observations is classified as “LOW”.
ECMO
Bridge to recovery
Based on the results of a pragmatic trial and an intention to treat analysis, referral of patient to an ECMO based centre significantly improves patient survival without disability compared to conventional ventilation. The results of CESAR trial showed that:
For patients with information about disability, survival without severe disability was significantly higher in ECMO arm
Assuming that the three patients in the conventional ventilation arm who did not have information about severe disability were all disabled, the results were also significant.
Assuming that none of these patients were disabled, the results were at borderline significance
A greater, though not statistically significant, proportion of patients in ECMO arm survived.
The rate of serious adverse events was higher among patients in ECMO group
The grade of evidence for the above observations is classified as “HIGH”.
Bridge to LTx
No studies fitting the inclusion criteria were identified.
There is no accurate data on the use of ECMO in patients awaiting LTx.
Economic Analysis
The objective of the economic analysis was to determine the costs associated with extracorporeal lung support technologies for bridge to LTx in adults. A literature search was conducted for which the target population was adults eligible for extracorporeal lung support. The primary analytic perspective was that of the Ministry of Health and Long-Term Care (MOHLTC). Articles published in English and fitting the following inclusion criteria were reviewed:
Full economic evaluations including cost-effectiveness analyses (CEA), cost-utility analyses (CUA), cost-benefit analyses (CBA);
Economic evaluations reporting incremental cost-effectiveness ratios (ICER) i.e. cost per quality adjusted life year (QALY), life years gained (LYG), or cost per event avoided; and
Studies in patients eligible for lung support technologies for to lung transplantation.
The search yielded no articles reporting comparative economic analyses.
Resource Use and Costs
Costs associated with both ILA and ECMO (outlined in Table ES-1) were obtained from the University Health Network (UHN) case costing initiative (personal communication, UHN, January 2010). Consultation with a clinical expert in the field was also conducted to verify resource utilization. The consultant was situated at the UHN in Toronto. The UHN has one ECMO machine, which cost approximately $100,000. The system is 18 years old and is used an average of 3 to 4 times a year with 35 procedures being performed over the last 9 years. The disposable cost per patient associated with ECMO is, on average, $2,200. There is a maintenance cost associated with the machine (not reported by the UHN), which is currently absorbed by the hospital’s biomedical engineering department.
The average capital cost of an ILA device is $7,100 per device, per patient, while the average cost of the reusable pump $65,000. The UHN has performed 16 of these procedures over the last 2.5 years. Similarly, there is a maintenance cost not that was reported by UHN but is absorbed by the hospital’s biomedical engineering department.
Resources Associated with Extracorporeal Lung Support Technologies
Hospital costs associated with ILA were based on the average cost incurred by the hospital for 11 cases performed in the FY 07/08 (personal communication, UHN, January 2010). The resources incurred with this hospital procedure included:
Device and disposables
OR transplant
Surgical ICU
Laboratory work
Medical imaging
Pharmacy
Clinical nutrition
Physiotherapy
Occupational therapy
Speech and language pathology
Social work
The average length of stay in hospital was 61 days for ILA (range: 5 to 164 days) and the average direct cost was $186,000 per case (range: $19,000 to $552,000). This procedure has a high staffing requirement to monitor patients in hospital, driving up the average cost per case.
PMCID: PMC3415698  PMID: 23074408
9.  The effect of tracheal tube size on air leak around the cuffs 
Background
This randomized single-blinded, cross-over study was done to evaluate the influence of the size of tracheal tubes on air leaks around the cuffs.
Methods
In a benchtop model, the number of longitudinal folds on the cuffs was evaluated for different sizes of tracheal tubes. In an anesthetized patient study, thirty patients scheduled for elective surgery under general anesthesia were included. After induction of anesthesia, the trachea was intubated with two sizes of tracheal tubes in a random sequence: in men, internal diameter of 7.5 mm and 8.0 mm; in women, internal diameter of 7.0 mm and 7.5 mm. After tracheal intubation with each tube, air leak pressures were evaluated at intracuff pressures of 20, 25 and 30 cmH2O by auscultation. To calculate the tracheal tube resistance (R), an inspiratory pause of 20% was applied and the resulting peak airway pressure (Ppeak), plateau pressure (Ppl) and mean expiratory tidal volume (Flow) were inserted in the formula R = (Ppeak - Ppl)/Flow.
Results
More longitudinal folds of the tracheal tube cuffs occurred in larger sized tubes compared to the smaller ones in a benchtop model. Air leakage was significantly less for the smaller tracheal tubes than for the larger ones for each gender at intracuff pressures of 20, 25 and 30 cmH2O. Tracheal tube resistances were not significantly altered by the size of tracheal tube.
Conclusions
The use of a smaller tracheal tube within an acceptable size can reduce air leakage around the cuff without significantly changing the tracheal tube resistance.
doi:10.4097/kjae.2011.61.1.24
PMCID: PMC3155132  PMID: 21860747
Anesthesia; Intratracheal; Intubation
10.  AB 63. Management of complex benign post-tracheostomy tracheal stenosis with bronchoscopic insertion of silicon tracheal stents, in patients with failed or contraindicated surgical reconstruction of trachea 
Journal of Thoracic Disease  2012;4(Suppl 1):AB63.
Background
Tracheal stenosis is a potentially life-threatening condition. Tracheostomy and endotracheal intubation remain the commonest causes of benign stenosis, despite improvements in design and management of tubes. Post-tracheostomy stenosis is more frequently encountered due to earlier performance of tracheostomy in intensive care units, while the incidence of post-intubation stenosis has decreased with application of high-volume low-pressure cuffs. We present tracheal stenting in complex post-tracheostomy stenoses.
Patients and methods
We inserted tracheal silicone stents (Dumon) under general anaesthesia through rigid bronchoscopy in two patients with benign post-tracheostomy stenoses: a 39-year old woman treated for acute respiratory failure (dyspnoea, hemoptysis, alveolar bleeding, attributed to seronegative lung vasculitis) who initially underwent surgical resection and end-to-end anastomosis, but developed restenosis (anastomotic granulation/scarring), and suffered continuous relapses after multiple bronchoscopic interventions, underwent silicone stenting (length 4.5 cm, diameter 12 mm). A 20-year old man treated for severe head trauma after a car accident developed a long tracheal stricture involving the subglottic larynx (lower posterior part), having inflamed tracheostomy site tissues (positive for methicillin resistant staphylococcus aureus), underwent silicone stenting (length 7 cm, diameter 14 mm).
Results
The airway was immediately re-establish, without complications (tracheal rupture/pneumomediastinum, bleeding). At 15 and 10 months follow-up (respectively) there was no stent migration, luminal patency was maintained without: adjacent structure erosion, secretion adherence inside the stents, granulation at the ends. Tracheostomy tissue inflammation was resolved (2nd patient), new infection was not noted. The patients maintain good respiratory function and will be evaluated for scheduled stent removal.
Conclusions
In symptomatic benign tracheal stenosis the gold standard is surgical reconstruction (often after interventional bronchoscopy). Stenting is reserved for symptomatic tracheal narrowing deemed inoperable due to local or general reasons: inflammation, long strictures, previous failed operation, poor respiratory, cardiac or neurological status. When stenting is decided, silicone stent insertion is considered treatment of choice in the presence of inflammation and/or when removal is desirable. Silicone stents are removable, resistant to microbial colonization and are associated with minimal granulation. In benign post-tracheostomy stenosis silicone stenting was safe and effective in re-stenosis after surgery and multiple bronchoscopic interventions, and in long stenosis in the presence on inflammation and poor neurological status.
doi:10.3978/j.issn.2072-1439.2012.s063
PMCID: PMC3537415
11.  Anesthetic management of a patient with Mounier-Kuhn syndrome undergoing off-pump coronary artery bypass graft surgery -A case report- 
Mounier-Kuhn-syndrome patients have markedly dilated trachea and main bronchi due to an atrophy or absence of elastic fibers and thinning of smooth muscle layers in the tracheobronchial tree. Although this syndrome is rare, airway management is challenging and general anesthesia may produce fatal results. However, only a few cases have been reported and this condition is not widely known among anesthesiologists. We present the case of a tracheobronchomegaly patient undergoing an emergency off-pump coronary artery bypass. Although the trachea was markedly dilated with numerous tracheal diverticuli, there was an undilated 2 cm portion below the vocal cords found on the preoperative CT. Under a preparation of extracorporeal membrane oxygenation, we intubated and placed the balloon of an endotracheal tube (I.D. 9 mm) at this portion, and maintained ventilation during the operation. This case showed that a precise preoperative evaluation and anesthetic plan is essential for successful anesthetic management.
doi:10.4097/kjae.2011.61.1.83
PMCID: PMC3155143  PMID: 21860757
Mounier-Kuhn syndrome; Tracheal diverticuli; Tracheobronchomegaly
12.  Direct Cannulation of the Infrahepatic Vena Cava for Emergent Cardiopulmonary Bypass Support 
Texas Heart Institute Journal  2009;36(4):316-320.
Cannulation for cardiopulmonary bypass, although seemingly routine, can pose technical challenges. In patients undergoing repeat sternotomy, for example, peripherally established cardiopulmonary bypass may be necessary to ensure safe entry into the chest; however, establishing bypass in this way can sometimes be complicated by patients' body habitus. We describe a technique for direct cannulation of the infrahepatic abdominal vena cava that was required for emergent cardiopulmonary bypass. The patient was a 62-year-old woman who had presented with severely symptomatic left main coronary stenosis 3 months after elective aortic valve replacement. She had gone into cardiogenic shock as general anesthesia was being induced for repeat sternotomy and myocardial revascularization. Emergent establishment of femorofemoral cardiopulmonary bypass was precluded by difficulties in advancing the femoral venous cannula beyond the pelvic brim. Hence, an emergent celiotomy was performed, and the abdominal vena cava was directly cannulated to establish venous drainage for cardiopulmonary bypass. The rest of the operation was uneventful. Our technique for direct cannulation of the infrahepatic abdominal vena cava may be used in exceptional circumstances. Necessary precautions and potential pitfalls are also presented.
PMCID: PMC2720288  PMID: 19693306
Cardiopulmonary bypass/instrumentation/methods; shock, cardiogenic; vena cava, inferior
13.  Case Report: Spinal Anesthesia by Mini-laminotomy for a Patient with Ankylosing Spondylitis who was Difficult to Anesthetize 
Background
Orthopaedic surgeons frequently encounter patients with ankylosing spondylitis who would benefit from various types of lower limb operations; however, some of these patients present challenges for anesthesiologists.
Case Description
We report the case of a 65-year-old patient with a fractured femoral component 30 years after a cemented THA. The patient had severe tracheal stenosis and ankylosing spondylitis making general endotracheal and conventional neuraxial anesthesia nearly impossible.
Literature Review
Possible alternative anesthetic approaches described in the literature include awake fiberoptic bronchoscopic guided intubation, laryngeal mask airway, and caudal anesthesia.
Purposes and Clinical Relevance
We achieved successful anesthesia using spinal laminotomy with the patient under local anesthesia followed by insertion of a spinal catheter and injection of an anesthetic agent. The loosened component was revised to a cementless THA.
doi:10.1007/s11999-010-1317-5
PMCID: PMC2974874  PMID: 20300899
14.  Case Report: Spinal Anesthesia by Mini-laminotomy for a Patient with Ankylosing Spondylitis who was Difficult to Anesthetize 
Background
Orthopaedic surgeons frequently encounter patients with ankylosing spondylitis who would benefit from various types of lower limb operations; however, some of these patients present challenges for anesthesiologists.
Case Description
We report the case of a 65-year-old patient with a fractured femoral component 30 years after a cemented THA. The patient had severe tracheal stenosis and ankylosing spondylitis making general endotracheal and conventional neuraxial anesthesia nearly impossible.
Literature Review
Possible alternative anesthetic approaches described in the literature include awake fiberoptic bronchoscopic guided intubation, laryngeal mask airway, and caudal anesthesia.
Purposes and Clinical Relevance
We achieved successful anesthesia using spinal laminotomy with the patient under local anesthesia followed by insertion of a spinal catheter and injection of an anesthetic agent. The loosened component was revised to a cementless THA.
doi:10.1007/s11999-010-1317-5
PMCID: PMC2974874  PMID: 20300899
15.  To assess the efficacy of i-gel for ventilation, blind tracheal intubation and nasogastric tube insertion 
Background:
The i-gel is a novel supraglottic airway device with a soft and non-inflatable cuff. In our study we attempted to evaluate the performance of i-gel as a ventilatory device, as a conduit to blind tracheal intubation using conventional polyvinyl chloride tracheal tube and gastric tube insertion through it.
Materials and Methods:
A total of 180 patients of American Society of Anesthesiologist (ASA) physical status I/II undergoing elective surgery under general anesthesia were included in this study. After induction of anesthesia, i-gel was inserted and the following parameters were recorded: Time taken for successful i-gel insertion, airway leak pressures, ease of gastric tube insertion and laryngeal view using fiberscope. Following this blind tracheal intubation was attempted. First attempt and overall success rate in blind tracheal intubation and gastric tube insertion were evaluated and tracheal intubation time was measured. Also presence of any side effects or complication following removal was recorded.
Results:
We achieved a 100% success rate in insertion of i-gel and in 171 out of 180 patients; i-gel was inserted in the 1st attempt itself. We also were able to achieve an overall success rate for blind endotracheal intubation via i-gel in 78.33% cases, and successful gastric tube placement was possible in 92.22%. In our study we also achieved a leak pressure of 25.52 (±2.33) cm of H2O.
Conclusion:
I-gel may be effectively used for ventilation, nasogastric tube insertion and as a conduit to blind endotracheal intubation with minimal complication and acceptable airway sealing pressures.
doi:10.4103/0259-1162.114012
PMCID: PMC4173497
I-gel; nasogastric tube; seal pressure; tracheal intubation
16.  Resection of thyroid carcinoma infiltrating the trachea. 
Thorax  1978;33(3):378-386.
We have treated surgically 11 patients with thyroid carcinoma that had infiltrated into the trachea. Three patients had primary tumours, and eight had recurrent tumours after previous operations. Sleeve resection of trachea was performed where thyroid carcinoma had proliferated; the trachea was reconstructed by end-to-end anastomosis. In two patients 10 rings of the trachea were resected. In three patients the anterior half of the cricoid cartilage was resected along with the cervical trachea. In one patient tracheoplasty was performed using partial extracorporeal circulation because severe tracheal stenosis prevented endotracheal intubation. Two of the 11 patients died from the surgery and one from disseminated metastases. One patient who had undergone tracheal resection for thyroid carcinoma three years and five months previously had a recurrence of the tumour in the trachea adjacent to the anastomosis, and a second tracheal resection was performed. In three patients postoperative laryngeal stenosis occurred. Five patients are alive and well two years and one month to four years and seven months after their operations. The histological pattern of the tumour was papillary adenocarcinoma in all 11 patients.
Images
PMCID: PMC470900  PMID: 684676
17.  Perioperative medical management of patients with COPD 
Chronic obstructive pulmonary disease (COPD) and heart diseases are considered independent risk factors for mortality and major cardiopulmonary complications after surgery. Coronary artery disease, heart failure and COPD share common risk factors and are often encountered, - isolated or combined -, in many surgical candidates. Perioperative optimization of these high-risk patients deserves a thorough understanding of the patient cardiopulmonary diseases as well as the respiratory consequences of surgery and anesthesia.
In contrast with cardiac risk stratification where the extent of heart disease largely influences postoperative cardiac outcome, surgical-related factors (ie, upper abdominal and intra-thoracic procedures, duration of anesthesia, presence of a nasogastric tube) largely dominate patient’s comorbidities as risk factors for postoperative pulmonary complications.
Although most COPD patients tolerate tracheal intubation under “smooth” anesthetic induction without serious adverse effects, regional anesthetic blockade and application of laryngeal masks or non-invasive positive pressure ventilation should be considered whenever possible, in order to provide optimal pain control and to prevent upper airway injuries as well as lung baro-volotrauma. Minimally-invasive procedures and modern multimodal analgesic regimen are helpful to minimize the surgical stress response, to speed up the physiological recovery process and to shorten the hospital stay. Reflex-induced bronchoconstriction and hyperdynamic inflation during mechanical ventilation could be prevented by using bronchodilating volatile anesthetics and adjusting the ventilatory settings with long expiration times. Intraoperatively, the depth of anesthesia, the circulatory volume and neuromuscular blockade should be assessed with modern physiological monitoring tools to titrate the administration of anesthetic agents, fluids and myorelaxant drugs. The recovery of postoperative lung volume can be facilitated by patient’s education and empowerment, lung recruitment maneuvers, non-invasive pressure support ventilation and early ambulation.
PMCID: PMC2699974  PMID: 18268924
anesthesia; surgery; COPD; atelectasis; functional residual capacity
18.  Isolated congenital tracheal stenosis in a preterm newborn 
European Journal of Pediatrics  2011;170(9):1217-1221.
Severe tracheal stenosis, resulting in functional atresia of the trachea is a rare congenital malformation with an estimated occurrence of two in 100,000 newborns. If no esophagotracheal fistula is present to allow for spontaneous breathing, this condition is usually fatal. We report on a male infant born at 32 weeks of gestation. The patient presented with respiratory distress immediately after delivery due to severe congenital tracheal stenosis resulting in functional atresia of the trachea. Endotracheal intubation failed and even emergency tracheotomy did not allow ventilation of the patient lungs. The patient finally succumbed to prolonged hypoxia due to functional tracheal atresia. The etiology of tracheal atresia and tracheal stenosis is still unclear, but both conditions are frequently combined with other anomalies of the VACTERL (vertebral anomalies, anal atresia, cardiovascular anomalies, tracheoesophageal fistula, esophageal atresia, renal/radial anomalies and limb defects) and TACRD (tracheal agenesis, cardiac, renal and duodenal malformations) association. Conclusion Successful treatment of severe congenital tracheal stenosis and tracheal atresia depends on either prenatal diagnosis or recognition of this condition immediately after birth to perform tracheotomy without delay. Nevertheless, despite any efforts, the therapeutical results of severe tracheal stenosis and tracheal atresia are still unsatisfactory.
doi:10.1007/s00431-011-1490-x
PMCID: PMC3158335  PMID: 21590265
Congenital tracheal stenosis; Neonate; Respiratory failure; VACTERL association
19.  Comparison of combitube, easy tube and tracheal tube for general anesthesia 
Background & Aims:
The Combitube® and EasyTube™ enable effective ventilation whether placed in the trachea or esophagus and can be used in prehospital settings, as well as in “Cannot Ventilate Cannot Intubate” situations in the operating room. Whether they can be continued to provide general anesthesia, if required, is not established. Thus the efficacy of Combitube and EasyTube was evaluated and compared with the tracheal tube for general anesthesia using controlled ventilation.
Materials and Methods:
Combitube, EasyTube and tracheal tubes were used in 30 patients each to secure the airway in a randomized controlled manner. Ventilatory parameters were measured along with hemodynamic variables, and characteristics related to device placement.
Results:
There was no significant difference in the various ventilatory parameters including minute ventilation requirement to maintain eucapnia amongst the three groups at any time point. There was no hypoxia or hypercarbia in any patient at any time. Placement of EasyTube was more difficult (P = 0.01) as compared with both Combitube and tracheal tube. EasyTube and Combitube resulted in higher incidence of minor trauma than with a tracheal tube (P = 0.00).
Conclusion:
Combitube and EasyTube may be continued for general anesthesia in patients undergoing elective nonlaparoscopic surgeries of moderate duration, if placed for airway maintenance. Given the secondary observations regarding placement characteristics of the airway devices, it, however cannot be concluded that the devices are a substitute for endotracheal tube for airway maintenance per se, unless specifically indicated
doi:10.4103/0970-9185.142849
PMCID: PMC4234790  PMID: 25425779
Combitube; EasyTube; general anesthesia
20.  TRALI Syndrome Complicated by Retroperitoneal Bleeding 
Transfusion-related acute lung injury (TRALI) is an underdiagnosed and underreported syndrome which by itself is the third leading cause of transfusion-related mortality. The incidence of TRALI is reported to be 1 in 2000 to 5000 transfusions. When combined with uncontrollable bleeding, survival is unachievable. We report the case of a 25-year-old man, who underwent open heart surgery as an infant to correct his congenital heart disease in association with right pulmonary artery atresia. He presented with hemoptysis secondary to aspergilloma and required a pneumonectomy of the nonfunctional right lung. During pneumolysis, significant bleeding occurred from the superior vena cava. The patient required a blood transfusion and was placed on cardiopulmonary bypass to control the bleeding. Simultaneous occurrence of severe pulmonary edema and retroperitoneal bleeding were noted. Approximately 8 L of frothy edema fluid were drained from the only functional left lung starting ~15 minutes after the transfusion and lasting for several hours until the end of the case. It most likely represented TRALI syndrome. Increasing abdominal girth and poor volume return to the pump were consistent with and pathognomonic for retroperitoneal bleeding. Though primary surgical bleeding in the chest was controlled successfully and a pneumonectomy performed without further difficulty, we were unable to separate the patient from cardiopulmonary bypass due to the inability to oxygenate. As a result, we could not reverse the anti-coagulation which potentially exacerbated the retroperitoneal bleeding. After multiple unsuccessful attempts the patient succumbed. This ill-fated case demonstrates the quandary of obtaining vascular access for emergency cardiopulmonary bypass while in the right thoracotomy position. It may be beneficial to have both the femoral artery and vein cannulated before positioning a patient in a lateral decubitus position. In addition, early direct access to the right atrium may obviate a need for femoral venous cannulation. Also, adult extracorporeal membrane oxygenation may be indicated if faced with such a severe pulmonary edema without ongoing hemorrhage.
doi:10.1055/s-0031-1283219
PMCID: PMC3331656  PMID: 22942633
Transfusion; lung injury; pulmonary atresia; retroperitoneal hematoma
21.  Subglottic stenosis following percutaneous tracheostomy: a single centre report as a descriptive study 
SUMMARY
Tracheal stenosis is a potential complication of tracheostomy. The present study aimed to describe the epidemiologic profile of subglottic stenosis in a referral medical centre. During a 4-year period, all patients who had been admitted in an Intensive Care Unit of Imam Khomeini Hospital (affiliated to Tehran University of Medical Sciences) and had undergone percutaneous tracheostomy during 7-10 days after endotracheal intubation were enrolled in the study. After removing the tracheostomy tube, patients were evaluated regarding development of tracheal stenosis using fiberoptic bronchoscopy and multi-slice computed tomography scan. During the study period, percutaneous tracheostomy was performed in 140 patients with a mean age of 38 years. Overall 54 patients died due to the severity of the disorder during hospitalization. In the remaining 86 patients, 54 cases needed permanent or long-term mechanical ventilation and were excluded from the study. Twelve patients died during the first 3 months and 20 patients were left for final assessment. Multi-slice computed tomography scan imaging showed subglottic stenosis in 17 cases (85%). Of these, 9 patients (52%) had tracheal stenosis of < 50%. Tracheal stenosis of 25- 40% was found in 5 cases (25%). Patients in whom the tracheostomy tube had been removed in the first 3 weeks after tracheostomy did not present tracheal stenosis (n = 3, 15%). The present study revealed that subglottic stenosis is frequent in patients who have undergone percutaneous tracheostomy in the Intensive Care unit setting. However, the stenosis is generally mild and is not associated with serious and/ or life-threatening clinical manifestations.
PMCID: PMC3203718  PMID: 22065821
Percutaneous tracheostomy; Intensive Care Unit; Subglottic stenosis
22.  An unanticipated difficult airway in Lesch–Nyhan syndrome 
An 11-year-old boy with Lesch–Nyhan syndrome presented to the emergency for fixation of a fractured femur. During induction of general anesthesia, unexpected difficult intubation was encountered with a 6.5-mm ID endotracheal tube and successively smaller tubes, also failing to pass 1 cm beyond the vocal cords. Intubation was finally achieved with a 4.5-mm ID tube. The surgery was completed uneventfully. A tracheal diverticulum was found in the computerized tomography (CT) scan performed postoperatively to account for this unexpected difficult intubation. This case highlights the anesthetic concerns in Lesch-Nyhan syndrome and also reports the rare occurrence of a tracheal diverticulum associated with it.
doi:10.4103/0970-9185.94909
PMCID: PMC3339734  PMID: 22557752
Difficult airway; Lesch–Nyhan syndrome; tracheal diverticulum
23.  Anesthetic experience of an adult patient with an unrecognized tracheal bronchus -A case report- 
Korean Journal of Anesthesiology  2010;59(Suppl):S13-S16.
We present a case of problematic tracheal intubation in an adult patient with an unrecognized tracheal bronchus. Immediately after tracheal intubation and position change to prone, bilateral breath sounds were almost absent, and there was a diminished tidal volume. In order to resolve the ventilatory difficulty, the wire-reinforced tube was replaced with a conventional tube, and proper positioning of the tube was completed under fiberoptic guidance. A tracheal bronchus (originating about 1.2 cm above the carina, and supplying the right upper lobe) was found on the postoperative chest CT. In the presence of tracheal bronchus, tracheal intubation may cause pulmonary complications. Anesthesiologists should keep in mind the anesthetic implications of tracheal bronchus, and must be familiar with the use of fiberoptic bronchoscopy for proper positioning of endotracheal tube.
doi:10.4097/kjae.2010.59.S.S13
PMCID: PMC3030018  PMID: 21286422
Endotracheal intubation; Tracheal bronchus
24.  Endotracheal tube cuff pressure monitoring during neurosurgery - Manual vs. automatic method 
Background:
Inflation and assessment of the endotracheal tube cuff pressure is often not appreciated as a critical aspect of endotracheal intubation. Appropriate endotracheal tube cuff pressure, endotracheal intubation seals the airway to prevent aspiration and provides for positive-pressure ventilation without air leak.
Materials and Methods:
Correlations between manual methods of assessing the pressure by an experienced anesthesiologists and assessment with maintenance of the pressure within the normal range by the automated pressure controller device were studied in 100 patients divided into two groups. In Group M, endotracheal tube cuff was inflated manually by a trained anesthesiologist and checked for its pressure hourly by cuff pressure monitor till the end of surgery. In Group C, endotracheal tube cuff was inflated by automated cuff pressure controller and pressure was maintained at 25-cm H2O throughout the surgeries. Repeated measure ANOVA was applied.
Results:
Repeated measure ANOVA results showed that average of endotracheal tube cuff pressure of 50 patients taken at seven different points is significantly different (F-value: 171.102, P-value: 0.000). Bonferroni correction test shows that average of endotracheal tube cuff pressure in all six groups are significantly different from constant group (P = 0.000). No case of laryngomalacia, tracheomalacia, tracheal stenosis, tracheoesophageal fistula or aspiration pneumonitis was observed.
Conclusions:
Endotracheal tube cuff pressure was significantly high when endotracheal tube cuff was inflated manually. The known complications of high endotracheal tube cuff pressure can be avoided if the cuff pressure controller device is used and manual methods cannot be relied upon for keeping the pressure within the recommended levels.
doi:10.4103/0970-9185.83682
PMCID: PMC3161462  PMID: 21897508
Automatic cuff pressure controller; endotracheal tube cuff pressure; manual method; neurosurgery
25.  Management of complex benign post-tracheostomy tracheal stenosis with bronchoscopic insertion of silicon tracheal stents, in patients with failed or contraindicated surgical reconstruction of trachea 
Journal of Thoracic Disease  2012;4(Suppl 1):32-40.
Tracheal stenosis is a potentially life-threatening condition. Tracheostomy and endotracheal intubation remain the commonest causes of benign stenosis, despite improvements in design and management of tubes. Post-tracheostomy stenosis is more frequently encountered due to earlier performance of tracheostomy in the intensive care units, while the incidence of post-intubation stenosis has decreased with application of high-volume, low-pressure cuffs. In symptomatic benign tracheal stenosis the gold standard is surgical reconstruction (often after interventional bronchoscopy). Stenting is reserved for symptomatic tracheal narrowing deemed inoperable, due to local or general reasons: long strictures, inflammation, poor respiratory, cardiac or neurological status. When stenting is decided, silicone stent insertion is considered the treatment of choice in the presence of inflammation and/or when removal is desirable. We inserted tracheal silicone stents (Dumon) under general anaesthesia through rigid bronchoscopy in two patients with benign post-tracheostomy stenosis: a 39-year old woman with failed initial operation, and continuous relapses with proliferation after multiple bronchscopic interventions, and a 20-year old man in a poor neurological status, with a long tracheal stricture involving the subglottic larynx (lower posterior part), and inflamed tracheostomy site tissues (positive for methicillin resistant staphylococcus aureus). The airway was immediately re-establish, without complications. At 15- and 10-month follow-up (respectively) there was no stent migration, luminal patency was maintained without: adjacent structure erosion, secretion adherence inside the stents, granulation at the ends. Tracheostomy tissue inflammation was resolved (2nd patient), new infection was not noted. The patients maintain good respiratory function and will be evaluated for scheduled stent removal. Silicone stents are removable, resistant to microbial colonization and are associated with minimal granulation. In benign post-tracheostomy stenosis silicone stenting appeared safe and effective in re-stenosis after surgery and multiple bronchoscopic interventions, and in long stenosis, involving the lower posterior subglottic larynx in the presence on inflammation and poor neurological status.
doi:10.3978/j.issn.2072-1439.2012.s002
PMCID: PMC3537388  PMID: 23304439
Airway obstruction/therapy; tracheal stenosis/therapy; stents; airway stenting; benign tracheal stenosis

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