Subglottic Space Research Articles

Partial cricotracheal resection with tracheal intussusception and cricoarytenoid joint mobilization: Early experience in a new technical variant

Partial cricotracheal resection with tracheal intussusception and cricoarytenoid joint mobilization: Early experience in a new technical variant

Increasing positive end expiratory pressure at extubation reduces subglottic secretion aspiration in a bench-top model

To estimate the ability of simulated tracheal suction, adjusting the positive end expiratory pressure (PEEP) settings on the ventilator or compressing a self-inflating bag to minimize aspiration during cuff deflation and extubation in a bench-top model. During intubation, colonized secretions accumulate in the subglottic space above the endotracheal tube (ETT) cuff. Consequently, during cuff deflation and extubation, there is a risk of aspiration of the secretions. This may result in pneumonitis or pneumonia. There are a number of techniques used during cuff deflation and extubation to prevent secretion aspiration. A model trachea was intubated and the proximal end of the ETT was attached to a mechanical ventilator. Ten millilitres of water was placed above the inflated cuff and then nine test protocols were implemented in a random order to simulate tracheal suction, adjusting the PEEP settings on the ventilator or compressing a self-inflating bag. The volume of water 'aspirated' by the model was determined by weighing the apparatus pre- and post-extubation. Statistical analysis was performed using regression analysis and heteroscedastic t tests with a Bonferroni correction. The level of PEEP was negatively correlated with the volume of fluid aspirated [co-efficient -0.24 (99% confidence interval -0.31 to -0.17), R(2) = 0.75]. Significantly less fluid was aspirated when a PEEP of 35 cmH(2)O was applied when compared with competing techniques. This study suggests that applying PEEP during cuff deflation and extubation is protective against aspiration. We conclude that unless there is a contraindication, the application of PEEP should be considered when extubating patients.

Evidence-Based Review and Discussion Points

Evidence-Based Review and Discussion Points

Reducing Ventilator-Associated Pneumonia Through Advanced Oral-Dental Care: A 48-Month Study

To determine the effect of implementing a comprehensive oral and dental care system and protocol on the rate of ventilator-associated pneumonia. Patients more than 18 years old receiving mechanical ventilation for more than 48 hours in a medical intensive care unit at a university-affiliated medical center were studied in 2 consecutive 24-month periods. Patients in the group studied before the intervention (n = 779) had no oral assessments, no suctioning of the subglottic space, no toothbrushing, and suctioning of secretions in the oral cavity as needed. The group studied during the intervention (n = 759) included patients treated under a protocol whereby the oral cavity was assessed, deep suctioning was done every 6 hours, oral tissue cleansing was done every 4 hours or as needed, and toothbrushing was done twice daily. Compliance with protocol components exceeded 80%. The groups did not differ significantly in age, sex, or severity of illness. The rate of ventilator-associated pneumonia was 12.0 per 1000 ventilator days before the intervention and decreased to 8.0 per 1000 ventilator days during the intervention (P = .06). Duration of mechanical ventilation and length of stay in the intensive care unit differed significantly between groups, as did mortality. Our findings suggest that use of advanced tools, a comprehensive oral care protocol, and staff compliance with the protocol can significantly reduce rates of ventilator-associated pneumonia and associated costs.

Pharmacodynamics of remifentanil blunting responses to tracheal intubation performed under peopofol anesthesia administered by TCI In patients with myasthenia gravis

Objective To investigate the pharmacodynamies of remifentanil blunting the responses to tracheal intubation performed under propofol anesthesia in patients with myasthenia gravis. Methods Forty-five ASA Ⅰ or Ⅱ patients with myasthenia gravis aged 18-64 yr weighing 45-95 kg scheduled for trans-stemal thymectomy were enrolled in this study. ECG, BP, HR, SpO2 and BIS were monitored. Anesthesia was induced with propofol and remifentanil both administered by TCI. The target plasma concentration (Cp) of propofol was set at 4 μg/ml during induction. The initial target effect-site concentration (Ce) of remifentanil was set at 1.8 ng/ml and was increased step by step to 2.7, 4.0 and 6.0 ng/ml until the patients could tolerate laryngoscopy and insertion of larynx unesthetic tube into subglottic space without body movement, coughing or bucking. Topical anesthesia of trachea was then performed by spraying 2% lidocaine 2 ml through the larynx anesthetic tube. Laryngoscope and larynx anesthetic tube were removed and the patients were ventilated with O2 through anesthetic mask for 1-2 min before tracheal intubation. The Ce50 and Ce95 (95% confidence interval) were calculated by Probit analysis. Results The Ce50 and Ce95 of remifentanil blunting responses to tracheal intubation performed with propofol administered by TCI was 2.2 ng/ml (95% CI 2.0-2.3 ng/ml) and 3.0 ng/ml (95% CI 2.8-3.5 ng/ml) respectively.Conclusion The Ce50 and Ce95 of remifentanil blunting responses to tracheal intubation performed under propofol anesthesia are 2.2 and 3.0 ng/ml respectively. Key words: Piperidines; Dose-response relationship,drug; Prepofol; Drug delivery systems; Intubation, intratrachesl; Myasthenia gravis

Morphology of the human larynx

Morphology of the human larynx. II. The subglottis The macroscopic staining method was used to display and measure the epithelium of the human subglottic space. Small islands of squamous metaplasia were found in about 40% of the non-smoking, non-bronchitic urban population. There was no age or sex difference, although a highly significant decrease in size of the subglottic space was found in women throughout life.

The LoTrach™ system: its role in the prevention of ventilator‐associated pneumonia

To discuss the development of the LoTrach system in light of current evidence around the prevention of ventilator-associated pneumonia (VAP) and its practical application in the intensive care setting. VAP causes substantial morbidity and mortality in ventilated patients in the Intensive Care Unit (ICU), increases length of stay in ICU and is extremely costly. Strategies are needed to reduce the risk of VAP. We examine the need for an endotracheal tube (ETT) specifically designed for the critically-ill patient, the development of the LoTrach system from conception to production, and the role of the various components of the system in preventing VAP. Early issues in implementing this revolutionary equipment into ICU are explored and three case studies highlight advantages of this system. The LoTrach system has been designed to facilitate the provision of a number of evidence-based interventions that have been shown to reduce VAP. Pulmonary aspiration is ubiquitous with conventional cuffs but prevented by the cuff of the LoTrach system when held at a constant and safe pressure against the tracheal wall with a cuff pressure controller. Other aspects incorporated in the ETT are aimed at clearing the secretions from the subglottic space, preventing tube occlusion and accidental extubation, and avoiding damage to the airway. In this way the LoTrach system employs a multifactorial approach to the prevention of VAP and the cost savings from LoTrach rather than a standard ETT will be considerable because of an average 3 day reduction in ICU length of stay related to this. It thus has the potential to be a very useful tool in the ICU setting in the prevention of VAP.

Erfahrungen mit der laryngotrachealen Erweiterung bei subglottischen Stenosen in einem Zeitraum von 30 Jahren

Severe subglottic stenosis is a difficult condition to manage. It can be treated by laryngotracheal reconstruction or cricotracheal resection. In this retrospective study the experiences for treatment of isolated subglottic stenosis in 37 patients (age: 3-78 years; stenosis grading: 20 x grade II, 13 x grade III, and 4 x grade IV) by laryngotracheal reconstruction in a 30-years experience are presented. In 33 out of 37 patients (89.2 %) a sufficient subglottic patency (postoperative endoscopic finding: stenosis less than 30 %) was achieved by laryngotracheal reconstruction. However, 5 patients of this series had required revision of laryngotracheal recontruction and in 22 patients endoscopic removal of granulation tissue had been performed. Sufficient widening of the subglottic space had been possible in all grade II stenosis (20/20), in 11 out of 13 patients with grade III stenosis, and in 3 out of 4 patients with grade IV stenosis. In one child an accidental decannulation occurred and due to asphyxia an apallic syndrome developed. Even through laryngotracheal reconstruction is a demanding surgical technique requiring great experience it is an effective option for treatment of subglottic stenosis less than 90 %. For severe subglottic stenosis (> 90 %) treatment by laryngotracheal reconstruction is possible and should be considered if mobilisation of the trachea by scar tissue is suited to be worse or to extended cricotracheal stenosis is present, both being not good candidates for cricotracheal resection.

ANCA-negative subglottische Kehlkopf-Stenose im Kindesalter

A 15-year-old female, having developed recurrent infections of the upper airway, hoarseness, dyspnea, and nasal congestion, was referred to our department. There was no history of trauma or intubation. The subglottic space was circularly narrowed. The test for c-ANCA was negative. Chest X-ray and renal function were normal. A tracheotomy was performed; the histology showed infiltrating plasma cells, but no signs of vasculitis or granulomatous inflammation. One year later the patient developed acute renal failure. Biopsy of the kidney confirmed Wegener's disease. The laryngeal stenosis completely resolved after therapy with cyclophosphamide. Juvenile Wegener's granulomatosis is extremely rare; the larynx and trachea seem to be involved more frequently in children than in adults. The positive testing of c-ANCA can support the diagnosis; however, even when c-ANCA do not test positive, the disease can never be excluded. Surgical interventions within the larynx or trachea might only be considered after ineffective therapy with immunosuppressive drugs.

Estenosis laringotraqueales: Resección y reconstrucción primaria

A review is made of patients with stenosis involving the larynx and trachea, treated in the thoracic surgery service of the Hospital de San Jose with resection and reconstruction techniques with primary anastomosis, during the period between 1996 and 2005. The histories were reviewed Clinical data and the information collected retrospectively were recorded in a database with: sex, age, origin, cause of the stenosis, location, severity, length, previous interventions related to the current problem, history of intubation, cause and duration of the same, time elapsed between extubation and the appearance of stenosis, stay in the ICU, history of tracheostomy, symptoms, management of acute airway obstruction, diagnostic images, endoscopic findings, surgical procedure performed, mortality, complications, time of hospitalization and functional results. Thirty patients, 16 men and 14 women were intervened. The age range varied between 12 and 80 years, with an average of 44. Twenty-seven patients had stenosis after intubation (25 orotracheal and 2 tracheostomy). The symptoms of obstruction occurred between 30 and 90 days after the procedure and the duration ranged between 3 and 45 days. In one patient an idiopathic stenosis was diagnosed, in another an inflammatory pseudotumor of the body of the trachea and in a third after trauma by firearm. In eight the narrowness compromised the laryngotracheal region, four in the subglottic space and four in the glottic in the posterior commissure. Seven of them secondary to orotracheal intubation and one idiopathic. In 22 patients it was located in the body of the trachea. The length of the narrow segment varied between 2 and 6 cm. The severity of the obstruction ranged between 70% and 90%. In two cases there was a combination of stenosis and tracheomalacia. The symptoms consisted of dyspnea of ​​effort and laryngeal stridor. There was acute obstruction of the airway in 18 and it was treated with tracheostomy in 16 and dilatations in two. Twelve patients had a tracheostomy tube when they visited the hospital. Three patients had undergone different procedures of resection and reconstruction in other institutions. In all cases, laryngeal and trachea CT and fibrobronchoscopy were performed. Three brought magnetic nuclear resonance at the time they were first evaluated in our service. Two patients were assessed in other institutions with linear tomography. In 14 patients with a clinical picture of airway obstruction, a volume flow curve was performed that showed a pattern of fixed obstruction of the upper airway. They were studied with arterial gases that showed mild to severe hypoxemia in ten and retention of CO in five. All the patients underwent resection and reconstruction by end-to-end anastomosis of the airway. In 26, a cervical approach was made and four required a combined cervical and sternal approach. In four patients with subglottic stenosis, resections were made of the anterior plate of the cartilage and the diseased mucosa, covering the defect with a membranous tracheal flap and anastomosis between the thyroid cartilage and the trachea. In one a tracheostomy cannula was left; in another, a plastic T tube was placed as a mold, which was maintained for seven months. The others were extubated at the end of the procedure. Four patients who presented lesions that compromised the glottis required a complex reconstruction consisting of a laryngofisura and resection of the entire anterior portion of the cricoid cartilage. In two, one T-tube was left for six months and in another a temporary tracheostomy cannula was placed. Twenty-two with stenosis of the body of the trachea were treated with resection and primary anastomosis of trachea segments whose length varied between 3 and 6 cm. Fifteen with resections larger than 3 cm required laryngeal release maneuvers. Three with stenosis greater than 5 cm required a median sternotomy for mobilization of the pulmonary hilum. In a patient with stenosis and tracheomalacia caused by compression by a goiter, the procedure was combined with a total thyroidectomy. One patient presented a new obstruction after the resection of a subglottic stenosis and was reoperated at six months. Hospitalization time varied between 8 and 20 days with an average of 9. There were two deaths due to tracheal fistulas with massive hemorrhage and seven complications in 30 resection and reconstruction procedures. The results obtained in 26 patients were excellent, with restoration of patency of the airway and recovery of the normal voice. To the extent that surgical reconstruction techniques have been perfected and experience with them is greater, We are increasingly convinced that resection and early reconstruction of these lesions is widely justified and that conservative treatment does not represent an appropriate alternative. Abbreviations: ICU, intensive care unit; CT scan, computerized axial tomography.

Cricoid ossification mimicking an impacted foreign body

A 54-year-old man complained of severe throat pain and showed subglottic oedema on fibre-optic endoscopy with a distinctly narrowed subglottic space on anteroposterior radiography of the neck and dense linear opacity at the level of the cricoid cartilage on lateral plain radiography. These findings suggested a foreign body just posterior to the cricopharyngeus, but a computed tomography (CT) scan demonstrated a dense calcified ridge on the posterior lamina of the cricoid cartilage but no foreign body.The patient improved symptomatically with systemic antibiotics and topical steroids, and gastrointestinal endoscopy did not detect any foreign body. This is a rare case of vertical ossification of the cricoid lamina masquerading as a foreign body.

A low-volume, low-pressure tracheal tube cuff reduces pulmonary aspiration*

Leakage of fluid from the subglottic space to the lungs occurs along the longitudinal folds within the wall of an inflated high-volume, low-pressure (HVLP) cuff. The low-volume, low-pressure (LVLP) cuff does not have these folds yet allows for convenient and reliable control of tracheal wall pressure. Pulmonary aspiration during anesthesia has been linked with postoperative pneumonia and during critical illness causes ventilator-associated pneumonia. Prospective, blinded, randomized controlled trial; prospective observational study; and benchtop models. Department of Anaesthesia and Critical Care, Queen Elizabeth Hospital. Anesthetized patients (n=38) and critically ill patients with either an LVLP or HVLP cuffed tracheostomy tube following swallow assessments (n=67). The LVLP cuff was compared with HVLP cuffs for leakage of dye placed in the subglottic space to the tracheobronchial tree in a rigid tracheal model and a benchtop pig trachea model (before and after a standardized cuff movement). In the rigid tracheal model, the incidence of leakage was 0% in the LVLP group and 100% in the HVLP group (p<.01). Dye leakage in the pig tracheal model with HVLP cuffs was 44% before tube movement, increasing to 79% afterward. The LVLP cuff did not leak in the pig tracheal model. Dye leakage in anesthetized patients was 0% before movement and 5% after in the LVLP group and in the HVLP group 22% increasing to 67% after movement (p<.001). Forty-nine percent of swallow assessments were scored as failed in the critical care patients with HVLP tracheostomy tube cuffs, and there were no episodes of aspiration following swallow assessment in the LVLP group (p<.05). The LVLP cuffed tracheal and tracheostomy tubes reduced pulmonary aspiration in the benchtop models and in anesthetized and critically ill patients. The single failure of the LVLP cuff in the anesthesia group was probably associated with accidental endobronchial intubation following tube movement.

Pulse oximetry does not reliably detect aspiration on videofluoroscopic swallowing study

Wang T-G, Chang Y-C, Chen S-Y, Hsiao T-Y. Pulse oximetry does not reliably detect aspiration on videofluoroscopic swallowing study. Arch Phys Med Rehabil 2005;86:730–4. Objective To examine the reliability of pulse oximetry for identifying aspiration by comparing it with the videofluoroscopic swallowing study (VFSS). Design Nonrandomized, prospective, double-blind study. Setting VFSS laboratory in a teaching hospital. Participants Sixty patients from among 130 patients with clinically diagnosed dysphagia between September and December 2002. Interventions Not applicable. Main outcome measures Simultaneously monitoring the arterial oxygen saturation (Sp o 2) by pulse oximetry while patients were performing VFSS. A decrease in Sp o 2 exceeding 3% was considered as significant desaturation. Bolus or portion of bolus passing through the vocal cords and entering the subglottic space was defined as aspiration on VFSS. The results of pulse oximetry and VFSS were compared. Results No significant correlation existed between desaturation measured by pulse oximetry and aspiration on VFSS (χ 2 test, P=.87). The positive predictive rate of pulse oximetry in detecting aspiration on VFSS was 39.1%, and the negative predictive rate was 59.4%. Conclusions Aspiration occurring on VFSS cannot be predicted based on decrease in Sp o 2 in pulse oximetry. The application of pulse oximetry to detect aspiration during regular meals requires further investigation.

Surgical management for posterior laryngeal cleft developing subglottic airway obstruction

A 3-year-old boy associated with Opitz syndrome including hypospadia and anorectal anomaly was transferred to Osaka University Hospital with orotracheal intubation because of respiratory distress after respiratory infection. He had laryngeal cleft diagnosed in the neonatal period because of symptoms including stridor and aspiration. After 2 attempts at extubation, tracheostomy was performed. Fiberscopic examination demonstrated obstruction of the airway from the vocal cord to subglottic space by inspired esophageal redundant mucosa. There was no improvement observed for 3 months. He underwent anterior repair of cleft, anterior laryngotracheoplasty with costal cartilage graft, closure of tracheostomy, and endoscopic Nissen fundoplication. The postoperative course during the subsequent year was uneventful without feeding or speaking disorders. Subglottic airway obstruction caused by inspired redundant mucosa is a rare complication in laryngeal cleft. Anterior laryngotracheoplasty and Nissen fundoplication should be considered for this complication, in addition to the usual procedure for cleft repair.

Rosai–Dorfman disease revealed in the upper airway: a case report and review of the literature

Rosai–Dorfman disease (RDD) is a systemic disease and its etiology is not well understood. It is a very rare but established disease. We report a case of RDD diagnosed in the upper airway that became a life-threatening condition because of the stricture of the subglottic space. A 49-year-old female complained of nasal obstruction, hoarseness and lacrimation. After evaluation following by fiberscopic examination and CT scanning of the head and neck, sinusitis and laryngeal masses were detected. Endoscopic sinus surgery and endolaryngeal microsurgery were performed simultaneously. The masses in the nasal cavity and larynx showed the same histological findings. Proliferative large histiocytes with voluminous clear cytoplasm and rounded nuclei, and lymphophagocytosis known as emperipolesis are the characteristic features of RDD. In this case, extranodal manifestations in the subglottic space gradually emerged postoperatively. Tracheotomy was performed to ensure an airway and prevent suffocation. An extensive treatment is not required in most patients with RDD, however, some patients who have extranodal manifestations involving the airway may detoriorate into a life-threatening condition.

Inspiratory activation of the vocal cord adductor, part II: Animal study in the cat.

The authors have shown previously that the vocal cord adductor is activated during inspiration in patients with vocal cord abduction impairment and that this adductor inspiratory activity is abolished by relief from inspiratory tracheal negative pressure by opening the tracheostoma. (Shiba K. Isono S, Sekita Y, Tanaka A. Inspiratory activation of the vocal cord adductor, Part I: human study in patients with restricted abduction of the vocal cords. Laryngoscope 2004;114:372-375). The authors hypothesized that insufficient opening of the glottis during inspiration generates strong negative pressure in the trachea and that this negative pressure triggers an airway reflex that activates the adductor. Experimental study of the mechanism of laryngeal obstruction using an animal model of restricted abduction of the vocal cords. To identify such an airway reflex, the authors recorded the adductor electromyogram in anesthetized cats whose vocal cords were mechanically adducted by stitching both cords together. To determine whether this reflex modulation of adductor activity is induced through afferents from the larynx or from the lower airway, the authors applied negative pressure to the subglottic space and lower airway separately. The adductor was activated during inspiration with powerful negative pressure in the trachea. Negative pressure in the subglottic space had a more marked effect on the adductor activity than did pressure in the lower airway. The adductor inspiratory activity was virtually abolished by laryngeal deafferentation. Glottal narrowing during inspiration reflexly activates the vocal cord adductor. This paradoxical inspiratory-related adductor activation is induced by an airway reflex triggered mainly through afferents from the larynx and probably contributes to stridor and dyspnea in patients with laryngeal obstruction.

Shortcomings of cuffed paediatric tracheal tubes

The goal of this investigation was to evaluate adequacy of the design of readily available paediatric cuffed tracheal tubes (CPTT). In 15 series of cuffed (11) and uncuffed (four) paediatric tracheal tubes (ID: 2.5-7.0 mm) from four different manufacturers the following dimensions were measured: outer diameter of the tube, position and largest diameter of the tube cuff inflated at 20 cm H(2)O and position of depth markings and compared with age-related dimensions. Outer diameters for tubes with similar IDs varied markedly between manufacturers and between cuffed and uncuffed tracheal tubes from the same manufacturer. Cuff diameters at 20 cm H(2)O cuff pressure and cross-sectional cuff area at 20 cm H(2)O cuff pressure did not always cover maximal internal age-related tracheal diameters and cross-sectional areas. Placing the tube tip in the mid-trachea, the cuffs of cuffed tubes with ID 3.0, 4.0, or 5.0 mm would become positioned within the larynx. If the cuffs were placed 1 cm below the cricoid level, many of the tube tips would be dangerously deep within the trachea. Only five of the 11 cuffed tubes had a depth marking. In many of these tubes the distances from depth marking to tube tip were greater than the age-related minimal tracheal length. Most cuffed paediatric tracheal tubes are poorly designed, in particular the smaller sizes. A better design of cuffed tubes with a short high-volume, low-pressure cuff, cuff-free subglottic space and adequately placed depth markings are urgently needed.

Anaerobic bacteria commonly colonize the lower airways of intubated ICU patients

To investigate respiratory tract colonization by aerobic and anaerobic bacteria in mechanically ventilated patients. Bacterial colonization of the stomach and the respiratory tract was qualitatively and quantitatively analyzed over time in 41 consecutive mechanically ventilated patients in a Swedish intensive care unit (ICU), with special emphasis on elucidation of the role of anaerobic bacteria in the lower respiratory tract. Samples were taken from the oropharynx, gastric juice, subglottic space and trachea within 24 h (median 14 h) of intubation, and then every third day until day 18 and every fifth day until day 33. The patients were often heavily colonized with microorganisms not considered to belong to a healthy normal oropharyngeal and gastric flora on admission to the ICU. A majority harbored enterococci, coagulase-negative staphylococci and Candida spp. in at least one site on day 1. Anaerobic bacteria, mainly peptostreptococci and Prevotella spp., were isolated from subglottic and/or tracheal secretions in 59% of the patients. Different routes of tracheal colonization for different groups of microorganisms were found. Primary or concomitant colonization of the oropharynx with staphylococci, enterococci, enterobacteria and Candida was often seen, while Pseudomonas spp., other non-fermenting Gram-negative rods and several anaerobic species often primarily colonized the trachea, indicating exogenous or direct gastrointestinal routes of colonization. Mechanically ventilated patients were heavily colonized in their lower airways by potential pathogenic microorganisms, including a high load of anaerobic bacteria. Different routes of colonization were shown for different species.

Percutaneous Dilatational Tracheostomy Technique

Percutaneous Dilatational Tracheostomy Technique

Frequent transmission of enterococcal strains between mechanically ventilated patients treated at an intensive care unit.

The objectives of this investigation were to study the respiratory tract colonization and transmission of enterococci between 20 patients treated with mechanical ventilation at an intensive care unit (ICU), to compare genotyping with phenotyping, and to determine the antibiotic susceptibilities of the isolated enterococci. Samples were collected from the oropharynx, stomach, subglottic space, and trachea within 24 h of intubation, every third day until day 18, and thereafter every fifth day until day 33. Enterococcal isolates (n = 170) were analyzed by pulsed-field gel electrophoresis and with the PhenePlate (PhP) system. The antimicrobial susceptibilities to five agents were determined. Seventeen of the 20 subjects were colonized with enterococci in the respiratory tract; 12 were colonized in the lower respiratory tract. Genotype analyses suggested that 13 patients were involved in a transmission event, including all patients intubated more than 12 days. In conclusion, colonization of resistant enterococci in the respiratory tract of intubated patients treated at an ICU was common. Transmission of enterococci between patients occurred frequently. Prolonged intubation period seems to be a risk factor for enterococcal cross-transmission.