Trauma And Postextubation Stridor Biology Essay


Endotracheal intubation is indicated only if respiratory function becomes severely compromised. Unfortunately, this measure may be of little benefit because the lesion may compress the bronchi distal to the tip of the endotracheal tube. {Montange, 1990 #190} In addition, it may be impossible to ventilate the child's lungs after muscle relaxants have been administered to facilitate placement of the endotracheal tube. Factors associated with the airway compromise are (1) anterior location of the mediastinal mass, (2) histological diagnosis of lymphoma, (3) symptoms and signs of superior vena cava syndrome, (4) radiological evidence of vessel compression or displacement, (5) pericardial effusion, and (6) pleural effusion. {Gothard, 2008 #289}


Postextubation Stridor

After endotracheal intubation that lasts more than a few hours, postextubation stridor is a relatively common problem in pediatric patients and is most frequently caused by laryngeal edema. Estimates of the frequency of postextubation stridor in children vary widely. Most authors cite figures of less than 2% to 25%, {Deakers, 1994 #172;Rivera, 1992 #193} although the incidence may be as high as 22%, which is slightly less than the incidence in the past, which has been as high at 37% in patients with trauma or burns. {Kemper, 1991 #187; Sandhu, 2000 #291}

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In addition to audible stridor, patients with this problem show decreased air movement; flaring of the alae nasi; and in more severe cases, decreased arterial oxygen saturation and mental status changes. The severity of these signs reliably indicates the severity of airway obstruction. {Kemper, 1992 #188}

Several risks are associated with the development of postextubation stridor. Endotracheal tube size plays an important role because too large an endotracheal tube may compress the tracheal mucosa, and this compression causes submucosal ischemia. When the endotracheal tube is removed, the injured tissue may swell and partially obstruct the larynx. Endotracheal tube movement within the trachea may also result in tissue injury and swelling. Whether stridor occurs depends on the extent of the swelling and the diameter of the child's airway. Small patients are more likely to have postextubation stridor because a larger proportion of their airway is obstructed with a given degree of swelling and because of the unfavorable characteristics of turbulent flow through small passages. Lack of an audible leak of air around the endotracheal tube is frequently used as a predictor of postextubation stridor in children. One study suggests that this measure may be valid only in children ages 7 years and older. Further recent studies reinforce that it is not possible to predict the extubation outcome for an individual patient with absolute certainly. Therefore, weaning and extubation practices in the pediatric critical care setting remain variable, and the development of standardized protocols for extubation remains controversial. {Wratney, 2006 #1007; Mhanna, 2002 #231}

Uncuffed endotracheal tubes are often recommended for children younger than 8 years because of concern that the presence of an endotracheal tube cuff may contribute to the risk of postextubation stridor. The subglottic region is the narrowest portion of the airway in this age group and will often provide an adequate seal around the endotracheal tube. Although cuffed endotracheal tubes are not frequently used in children younger than 8 years, there may not be compelling reasons to avoid the use of such endotracheal tubes. Data regarding the harmful effects of cuffed endotracheal tubes were derived from tubes with high-pressure, low-volume cuffs, which are likely to cause submucosal tracheal ischemia. These endotracheal tubes have been replaced by low-pressure, high-volume cuffs that seal the trachea by providing a larger area of contact with the mucosa at a lower pressure, resulting in less submucosal ischemia. When such endotracheal tubes are used, the risk of postextubation stridor appears no greater than when uncuffed endotracheal tubes are used. {Newth, 2004 #1008; Ashteckar, 2005 #1009; Deakers, 1994 #172} As cuffed endotracheal tubes may provide a better seal than uncuffed endotracheal tubes, they can be useful in delivering higher pressures needed in patients with noncompliant lungs who require mechanical ventilation.

Postextubation stridor has a greater risk of developing in children with trisomy 21; as many as one third of these patients have stridor after extubation. There appear to be several causes for this problem, including hypotonia and facial abnormalities, such as a large tongue.

Although most cases of postextubation stridor are caused by laryngeal edema, when this problem persists, other causes should be sought. Anatomical airway anomalies, which may not be visible during endotracheal intubation (such as a tracheal hemangioma), may cause persistent postextubation stridor. Vocal cord paralysis is one of the more common causes of persistent postextubation stridor and may be caused by increased intracranial pressure, {Chaten, 1991 #168} brainstem compression, trauma to the brainstem after neurosurgery, or recurrent laryngeal nerve during thoracic surgery. {Zbar, 1996 #240}

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The therapy of postextubation stridor is aimed at reducing airway edema. Racemic epinephrine and dexamethasone are the most widely used therapeutic agents. Racemic epinephrine, delivered by aerosol nebulizer, probably works by stimulation of ?-adrenergic receptors; this stimulation causes vasoconstriction, which, in turn, reduces tracheal edema. Racemic epinephrine works rapidly, so improvement, when it occurs, should be observed within a few minutes of completion of therapy. Mixtures of helium and oxygen have also proven helpful in the treatment of postextubation stridor. {Jaber, 2003 #1010; Kemper, 1991 #186}

The practice of using dexamethasone to treat postextubation stridor is widespread. Recent meta-analyses indicate that prophylactic administration of dexamethasone before elective extubation may the prevalence of postextubation stridor in neonates and children. It is inconclusive whether it may reduce the rate of reintubation. {Khemani, 2009 #1011; Darmon, 1992 #171; Ferrara, 1989 #177; Tellez, 1991 #196}

In most cases, postextubation stridor is self-limited, but occasionally, endotracheal intubation may be necessary. If the degree of airway obstruction before reintubation was severe, postobstructive pulmonary edema may be observed and should be treated with positive end-expiratory pressure. When reintubation is contemplated, the size of the previous endotracheal tube should be determined, and a smaller endotracheal tube should be selected in the effort of preventing additional tracheal injury. Ideally, the trachea should remain intubated until a leak around the endotracheal tube is observed, indicating resolution of the laryngeal edema.

Acquired Laryngotracheal (Subglottic) Stenosis

Laryngotracheal (subglottic) stenosis may be congenital, but acquired subglottic stenosis is a well-described complication following endotracheal intubation (Fig. 39'14). This process is multifactorial. It appears to result from an interaction of several elements, including individual susceptibility, movement of the endotracheal tube, size of the endotracheal tube, and duration of intubation. Many think that choosing the smallest tube that allows adequate ventilation and pulmonary toilet reduces the risk of subglottic stenosis. Fortunately, the incidence of this complication in neonates appears to be decreasing. {Walner, 2001 #236} It is also thought that nasotracheal intubation may reduce movement of the endotracheal tube within the trachea and diminish tracheal trauma. It has been reported that subglottic stenosis occurs infrequently after nasotracheal intubation with a proper-sized endotracheal tube. Gastroesophageal reflux is frequently present and perhaps plays a significant role in the development of laryngotracheal stenosis. {Walner, 2001 #236}

Mild subglottic stenosis may be treated expectantly. Parents should be counseled to be aware that stridor may occur with respiratory infections. More severe forms of subglottic stenosis must be treated surgically. A complex array of surgical options is available. {Cotton, 1999 #214} When reconstruction is attempted, it should occur at a younger age (younger than 25 months) so that the child's speech and language development is not impaired. {Zalzal, 1997 #239} Although this approach will avoid the need for tracheotomy and facilitate speech and language development, this recommendation may be at the price of laryngotracheal reconstruction failure and requirement for revision procedures. Postoperative management of these patients is frequently complicated by the need to maintain an artificial airway with minimal movement for many (5 to 14) days. This commonly requires the administration of sedatives, analgesics, and occasionally neuromuscular blocking agents. Fortunately, improvements in postoperative care have resulted in improved outcomes after laryngotracheal reconstruction. {Yellon, 1997 #238}. Over time the best surgical practice will develop that will allow lower failure rates. Pediatric surgeons and otolaryngologists are also developing newer techniques such as partial cricotracheal resection for use in infants and children which over time may acheive better results than with laryngotracheal reconstructions. (Sandu, 2008 # 1012)

Foreign Body Aspiration

Airway obstruction may be produced by aspiration of a variety of foreign bodies, with nuts being one of the most frequent offenders in children. Organic foreign bodies were most commonly found in a more recent study. Differences exist in the type of organic foreign body aspirated, with popcorn being retrieved in 15% of cases. There is also an increase in bronchoscopically removed small toy parts in more recent years. {White, 2004 #1013; Weissberg, 1987 #139} Most of the patients aspirating foreign bodies are ages 1 to 3 years with more than 95% being younger than 10 years. Less than 30% of patients aspirating foreign bodies receive medical attention within the first 24 hours, with many patients experiencing a significant delay before seeking medical attention. A clear history of foreign body aspiration may be elicited from 40% to 80% of the patients. Frequently it may escape notice by the parents as well as the physicians, because of the lack of knowledge of the exact history and inconclusive radiographical findings. {Yadav, 2007 #1014; Wolach, 1994 #197} Prevention and early recognition remain critical factors in the treatment of foreign body inhalation in children. Patients with an aspirated foreign body may initially be symptom free or may have a cough, wheezing, and evidence of respiratory embarrassment. Patients without symptoms who do not seek medical attention may have a persistent cough and ultimately pneumonia distal to the obstructed bronchus. Recurrent bouts of pneumonia may lead to bronchiectasis if the foreign body is not removed.

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The airway may be blocked anywhere from the posterior pharynx to the bronchi. The symptoms produced by foreign body aspiration vary according to the site of the foreign body and the degree of obstruction it produces. Foreign bodies of the extrathoracic airway characteristically produce inspiratory stridor. Foreign bodies lodged in the intrathoracic trachea and bronchi tend to produce wheezing.

Radiographic evaluation should include inspiratory and expiratory radiographs because a single anteroposterior radiograph will be unremarkable in 18% of children with an aspirated foreign body (Fig. 39'15). {Wolach, 1994 #197} If the foreign body is producing ball valve bronchial obstruction, hyperinflation of the involved lung will be seen during the expiratory radiogram. Many foreign bodies are not radiopaque, so failure to see a foreign body on the chest radiograph cannot exclude this diagnosis. If a suspicion of an aspiration is high, a bronchoscopy is warranted (Fig. 39'16).

Foreign bodies are removed from the tracheobronchial tree with a bronchoscope. {Mantel, 1986 #108} Depending on the material, this may be a difficult procedure, although improvement in bronchoscopes in recent years has greatly facilitated this undertaking. Cardiopulmonary bypass has been successfully used to support a patient who had extensive foreign body aspiration. Occasionally, bronchoscopic extraction is unsuccessful, and a pulmonary lobectomy is required.

Traumatic Injury to the Airway

Traumatic injury to the upper airway may be divided into two broad categories: oral facial trauma and laryngeal/tracheal trauma. Patients with obvious oral facial trauma may be at risk for upper airway obstruction. Even if the patients have no sign of respiratory distress at the time of presentation, swelling of soft tissues and hemorrhaging to the airway may lead to airway compromise.

Patients who must undergo operative intervention to treat their traumatic injuries need careful evaluation of their airway, including radiographs and CT scan examination. Traumatic injuries may make intubations in the trachea difficult in these patients. For this reason, sedation is to be avoided and endotracheal intubation with the patient awake should be considered. This may be accomplished with direct laryngoscopy after local anesthesia has been applied to the patient's oropharynx. In more difficult cases, it may be necessary to use a fiberoptic bronchoscope to guide the endotracheal tube into the trachea.

Postoperatively, patients undergoing repair of facial trauma may have their jaw wired shut. These patients should undergo extubation only when fully awake after resolution of their airway and facial edema. Instruments to open the wires should always be kept at the patient's bedside. Emesis may present a grave hazard in these patients.

Injury to the larynx and trachea may occur after blunt trauma such as automobile accidents or after penetrating trauma. Blunt trauma to the neck may lead to fracture of the cartilaginous rings supporting the trachea or to disruption of the tracheal mucosa. In the latter case, attempted endotracheal intubation may worsen a partial tracheal transection and create an airway emergency. {Kadish, 1994 #185} Signs of laryngeal injury include dyspnea, altered phonation, pain on swallowing, hoarseness, swelling, and subcutaneous emphysema of the neck. The development of subcutaneous emphysema after blunt trauma to the neck suggests that a laryngeal fracture or tracheal tear has occurred. The quantity of air in the subcutaneous tissues does not correlate with the severity of the injury. Establishment of an adequate airway is an essential consideration. Acute trauma of the larynx is often treated with placement of a tracheostomy before surgical repair of the larynx.

Blunt thoracic trauma can cause tracheal or bronchial disruption. Most commonly, these are 'blowout' injuries that result in tracheobronchial disruption. These injuries usually occur near the carina, and most involve mainstem bronchi. {Hancock, 1991 #181} Because children have flexible ribs, severe intrathoracic injuries can occur without rib fractures. The signs of tracheobronchial disruption include persistent air leak, failure to expand the lung with thoracostomy tube drainage, and massive atelectasis (from failure to conduct gas through an injured bronchus). Diagnosis of these injuries is usually made with bronchoscopy. Although small tracheobronchial disruptions may be managed conservatively, most of these lesions require surgical repair. {Hancock, 1991 #181}

Burn Injury to the Upper Airway

Thermal injury to the upper airway may complicate the management of a patient with burns. The presence of facial burns and singed nasal hairs, hoarseness, or inspiratory stridor should suggest the possibility of burn injury to the upper airway. Although respiratory compromise may not be present at the time of admission, it may develop later as swelling of the injured airway becomes more severe. Because of the efficient cooling capacity of the upper air passages, thermal injury to the airway below the vocal cords is uncommon, occurring in less than 5% of all hospitalized patients with burns.

Evidence of respiratory embarrassment in a patient with burns should be rapidly evaluated. Neck radiographs and fiberoptic examination of the larynx may show swelling of the soft tissues of the airway. If these findings are present, endotracheal intubation should be expeditiously performed to secure the airway before obstruction occurs. Because of the risk of infection, attempts are made to avoid tracheostomy placement in the patient with burns. Upper airway embarrassment is often accompanied by smoke inhalation injury to the lower airway, resulting in hypoxemia and hypercapnia. The products of combustion result in severe carbon monoxide intoxication or cyanide poisoning, both of which have nonspecific symptoms but require prompt medical therapy. {Ruddy, 1994 #199}


Angioedema is a well-demarcated localized edema involving the deep layers of skin, including the subcutaneous tissue. Angioedema may occur in response to a variety of systemic disorders, including allergic reactions that are mediated with immunoglobulin E, anaphylactic and anaphylactoid reactions, and other illnesses. Angioedema may lead to swelling of the soft tissue of the face, particularly the eyes and lips. If this should involve the soft tissues of the upper respiratory tract, laryngeal obstruction may result. Administration of subcutaneous epinephrine may dramatically reduce swelling caused by this condition. Occasionally, respiratory embarrassment caused by this condition is so severe that endotracheal intubation is warranted. The evaluation of patients with this disorder should be directed at (1) the identification of the causative agents so that the patients can avoid these in the future and (2) the anatomical site of presentation to allow stratification of airway risk and planning of appropriate triage for airway intervention. {Ishoo, 1999 #223}


Indications for the placement of a tracheostomy fall into three broad, frequently overlapping categories: airway obstruction, assisted ventilation, and pulmonary toilet. Pediatric anatomical anomalies that may necessitate tracheostomy are most often manifested in the neonatal period or in infancy, although some may not appear until childhood. The most common abnormalities include vocal cord paralysis (congenital and postbirth injury), subglottic stenosis, tracheal stenosis, cystic hygroma, tracheal hemangioma, and laryngeal cyst. The accurate diagnosis of these problems is frequently made during bronchoscopic examination of the larynx and trachea while the patient is anesthetized. If the obstruction is of sufficient magnitude, consideration should be given to doing a tracheostomy at the time of bronchoscopy.

Infants may require a tracheostomy because of the need for prolonged periods of assisted ventilation. The advent of neonatal intensive care has enabled small preterm infants to survive despite severe respiratory illness. Many of these patients will need lengthy periods of mechanical ventilation to treat infant respiratory distress syndrome and bronchopulmonary dysplasia. Prolonged intubation may lead to subglottic stenosis. {Nau, 1986 #115} For a reduction in the frequency of this complication, a tracheostomy may be performed. The optimal timing of tracheostomy for children who need long-term intubation is controversial. In many neonatal ICUs, infants needing mechanical ventilatory support for more than 30 to 45 days will undergo a tracheostomy. Indications for tracheostomy in children are changing however the most common indication remains prolonged ventilation. The peak incidence of tracheostomy is in patients less than 1 year of age. Except under emergency conditions, pediatric tracheostomy should be performed in the operating room with the child intubated. Tracheostomy mortality can occur in up to 40% of pediatric cases, however the tracheostomy-related mortality rate is only 0 to 6%. The procedure is safe and with a low number of complications if carried out at a tertiary hospital by a trained and experienced team. {Fraga, 2009 #1015; Carr, 2001 #213;Wetmore, 1999 #237} One recent study provided evidence that long-term tracheostomy is associated with airway inflammation (number of cells, neutrophils), more frequent bacteria, and reduced concentration of surfactant protein-D. {Griese, 2004 #221} The decline of polio in the United States during the decade following 1950 dramatically decreased the number of tracheostomies performed to facilitate mechanical ventilation and pulmonary toilet. Nevertheless, several pediatric diseases predictably lead to prolonged neuromuscular failure. Infants with infant botulism may have prolonged neuromuscular weakness and may undergo a tracheostomy to simplify management of mechanical ventilation. Similarly, older children with Guillain-Barr' syndrome and respiratory failure may need a tracheostomy if a lengthy course of mechanical ventilation is expected. The use of tracheostomy has been advocated to promote pulmonary toilet and improve ventilation during the treatment of flail chest.

The timing of the tracheostomy will depend on several issues, including the patient's underlying illness and the severity of the condition that makes tracheostomy necessary. If possible, emergency tracheostomy under unfavorable conditions should be avoided because the complications are more common in this setting. Percutaneous placement of a tracheostomy has been widely used in the adult population; however, experience in children remains limited. One small retrospective series suggests that placement in the ICU can be done safely with adherence to sound techniques and prudent patient selection. {Klotz, 2001 #226}

Postoperative Nursing Care

Care from attentive, trained nurses is essential for the well-being of the patient with a tracheostomy. Until a tract of granulation tissue has formed in the stoma between the cervical and tracheal epithelium, precautions should be taken to prevent the accidental displacement of the tracheostomy tube. Although stay sutures simplify replacement of the tracheostomy tube, this procedure may be difficult, especially in an emergency situation with a struggling patient. A hastily replaced tube may be incorrectly located in the pretracheal soft tissue resulting in asphyxiation. If positive-pressure ventilation is attempted with the tube in this position, subcutaneous and mediastinal emphysema may be followed by a life-threatening tension pneumothorax. Because of these risks, patients routinely stay in the ICU for 5 to 7 days postoperatively. Smaller children have arm restraints placed to prevent them from pulling at the tracheostomy tube. If necessary, sedation is given until the child grows accustomed to the tracheostomy and the tract matures with the formation of granulation tissue. If accidental displacement of the tracheostomy tube does occur, replacement may be facilitated with a gentle insertion of a 0 Miller laryngoscope blade into the stoma and the identification of the tracheal lumen before the tube is passed.

Besides avoiding accidental displacement of the tracheostomy, the nurse must constantly monitor the patient for obstruction of the tracheostomy tube. The tube may be obstructed by dried tracheal mucus. Sometimes the patient's chin may obstruct the tube. Humidified gas may be administered to prevent drying and inspissation of secretions.


Any operation on the airway involves risk. The complication rate after tracheostomy has been reported to be 10% to 30%, with a death rate of 3%. Early postoperative complications include air leak, hemorrhage, and aspiration. Air leak is seen more often in children than in adults and may be life threatening. The risk of complications declines as the patient ages. Some life-threatening complications, such as accidental decannulation or tracheostomy tube obstruction, may occur anytime after the placement of a tracheostomy. The safety and well-being of patients with a tracheostomy require constant vigilance to prevent these mishaps.

Swallowing dysfunction after tracheostomy may lead to aspiration of saliva and food. This may be due in part to anchoring of the trachea to the skin of the neck, preventing the cephalad movement of the trachea during swallowing. Children who have a tracheostomy often have difficulty learning to eat. The high frequency of pneumonia observed after tracheostomy may be in part due to the problem of recurrent aspiration. Aerophagia, another form of swallowing dysfunction, occurs with modest frequency in pediatric patients after tracheostomy.

Late complications include granulation tissue formation, tracheal stenosis, infection of the stoma, pneumonia, fused vocal cords, and distal tracheomalacia. Although infection of the stoma and distal tracheomalacia may be evident before decannulation, granulation formation and fused vocal cords may not be apparent until decannulation is attempted. An uncommon, but particularly dangerous late complication is erosion of the tracheostomy tube into the innominate artery.


Problems at the time of decannulation occur in up to 36% of children. These difficulties are most frequent in patients younger than 1 year. Structural abnormalities that result in decannulation problems include subglottic stenosis, tracheomalacia at the tracheostomy site, granuloma tissue obstructing the trachea, and fused vocal cords. If respiratory distress is encountered during decannulation, it should not be attributed to the patient's psychological dependence on the tracheostomy tube. Evaluation of the airway with bronchoscopy or a lateral neck radiograph is important. Psychological factors should not be considered until structural causes of respiratory embarrassment have been eliminated.