- Email: [email protected]
Severe Upper Airway Obstruction
Intensive Care
0031-3955/87 $0.00
+ .20
Severe Upper Airway Obstruction Henry Kilham, MD, FRACP, * Jonathan Gillis, MD, FRACP, t and Bruce Benjamin, MD, FRACSt
"Whatever else you do, maintain an adequate airway!"
This article describes management of newborn and older children with severe upper airway obstruction, that is, those needing or likely to need airways support for their intact survival. These children have more to gain from optimal care, and more to lose from any error than most other children requiring admission to a pediatric intensive care unit. Special difficulties arise from delayed or incorrect diagnosis, rapid or unpredictable progression to respiratory failure, confusion over the value of investigations, and difficulty in assessing the need for an artificial airway. Intubation skills are critical. A child with severe airway obstruction will make obvious any organizational and procedural strengths and weakness in a hospital. Severe acute airway obstruction in infants and children is not uncommon. It has relatively few causes (Table 1), croup and supraglottitis predominating. Although the principal aim of management is to prevent hypoxemia and its damaging and potentially fatal consequences, practices vary widely. Each hospital must have clear-cut protocols and procedures to cope with the child with airway obstruction, taking into account available skills and facilities. Airway obstruction in the newborn is infrequent. Causes are numerous (Table 2), most of them congenital abnormalities. Subspecialty referral will often be necessary for diagnosis and treatment. A different approach is required for the newborn; this is described separately. More general reviews on croup and supraglottitis are already available. I, 7, 9, 20, 22 This review highlights the intensive care aspects of this problem. The management plan below is based on that used in the Children's Hospital, Sydney, Australia, a 320-bed referral teaching hospital serving a total population of 6 million. *StaH' PhYSician, Pediatric Intensive Care Unit tDirector of Intensive Care, Deputy Head, Department of Medicine tStaH' Physician, Pediatric Intensive Care Unit From The Royal Alexandra Hospital for Children, Camperdown, New South Wales, Australia
Pediatric Clinics of North America-Vol. 34, No.1, February 1987
1
2
HENRY KILHAM ET AL.
Table 1. Serious Acute Upper Airway Obstruction in the Infant and Child Infections Acute laryngotracheobronchitis Supraglottitis (epiglottitis) Diphtheria Bacterial tracheitis (pseudomembranous croup) Pharyngeal abscesses (e.g., retropharyngeal) Tonsillitis/tonsillar hypertrophy Accidents/trauma Glottic, subglottic, or esophageal foreign body External trauma to neck Burns to upper airway Iatrogenic Postintubation Postinstrumentation Others Angioedema Spasmodic croup Tumors (e.g., lymphoma in anterior mediastinum)
Table 2. Causes of Acute Upper Airway Obstruction in the Newborn Nasal cavity and nasopharynx Bilateral posterior choanal atresia* Fractured nose or deviated septum due to birth trauma Turbinate hypertrophy ("stuffY nose syndrome") Tumor (e.g., encephalocele, dermoid, chordoma, hematoma)* Facial skeletal abnormalities Pierre Robin syndrome (micrognathia, glossoptosis, cleft palate)* Treacher-Collins syndrome (mandibulofacial dysostosis)* Apert's syndrome (acrocephalosyndactyly)* Crouzon's syndrome (craniofacial dysostosis)* Oral cavity and oropharynx Macroglossia (primary and secondary) Aberrent thyroid tissue or internal thyroglossal duct cyst* Pharyngeal tumor (e.g., cystic hygroma, dermoid, hemangioma) Larynx Laryngomalacia ("infantile larynx") Bilateral vocal cord paralysis* Congenital subglottic stenosis* Congenital laryngeal web* Subglottic hemangioma Cystic obstruction Laryngeal papilloma Trachea Vascular ring compression (double aortic arch) Innominate artery compression *Conditions especially likely to cause early, severe obstruction.
·3
SEVERE UPPER AIRWAY OBSTRUCTION
SEVERE AIRWAY OBSTRUCTION IN THE INFANT AND OLDER CHILD Important Principles of Management 1. Ensuring an adequate airway, where necessary by tracheal intubation, takes precedence over any other diagnostic or therapeutic maneuver. 2. Conversely, unnecessary intervention will greatly increase distress at serious risk to the child. 3. Optimal management will result from combining the skills of the pediatrician, otolaryngologist, and pediatric anesthesiologist.
Sequence of events in management are summarized in Table 3. Possible etiologies are listed in Table 1. Etiology can often be determined from history and physical signs; other reviews 1 • 2. 7. 9. 20. 22 more comprehensively cover this aspect.
Table 3. Management of Upper Airway Obstruction at the Children's Hospital,
Sydney, Australia 1. Team consists of Emergency Department, residents, intensive care unit physicians, otolaryngology and anesthesiology staff members. 2. Children with Angioedema Severe upper airway obstruction I Suspected supraglottitis Page team Suspected foreign body inhalation urgently
CO~ing I I
Respiratory occurring now
Pog"
""'I
....,.,dy
Oxygenation and emergency intubation by fue most skilled individual available.
I
1
Failed intubation is extremely rare: [ emergency tracheotomy may fuen be "last resort"
I
Intensive care unit
I
[~;::;~~s::~ynaryngOSCOPYl only if diagnosis requires furtiIer elucidation.
I
adequately at this stage
Give humidified O2 , 1M epinephrine (0.01 mls per kg)
.;,,"mr ""m
Review need for further treatment: repeat epinephrine, intubation
Give humidified O2 by mask (parent and child to hold)
'"
Suspected laryngotracheobronchitis. Consider nebulized epinephrine.
Review need for intervention. If severe obstruction persists
/'
Take to operating room where condition permits use of O/halothane to allow a more controlled situation for intubation, limited endoscopic examination as necessary.
I
Intensive care unit
I
4
HENRY KILHAM ET AL.
The possibility of supraglottitis must always be kept in mind, as unpredictable progression to total obstruction is likely. Supraglottitis usually presents as a rapidly progressive illness with toxicity, fever, dysphagia, and drooling associated with upper airway obstruction. Cough is often not prominent; stridor is often soft and low-pitched and both voice and cry are muffled. Symptoms of toxicity may predominate so that the respiratory signs may be overlooked or misinterpreted as asthma or pneumonia. There is usually no difficulty differentiating supraglottitis from acute laryngotracheobronchitis with its barking cough, inspiratory stridor, and hoarseness. Differentiation between supraglottitis and bacterial tracheitis may be more difficult, the latter condition also often producing severe toxicity. Foreign body inhalation should always be considered if there is a history of a choking episode or unusual features in the history or clinical signs, for example, variable distress according to posture of asymmetric chest findings. The state of immunization should always be checked when considering diphtheria. Angioedema is more likely in preschool and school-aged children and is usually suggested by its associated swollen facial tissues and often urticaria. In essence, the important initial distinction is only between those who need either intubation or examination under anesthesia and those who require careful observation with more leisurely investigation. All of those patients who have 1. Suspected supraglottic pathology 2. Severe respiratory distress from upper airway obstruction 3. Suspected foreign body inhalation
should be taken to the operating theater, as outlined below. Assessing the Severity of Upper Airway Obstruction A previously healthy infant or child will readily tolerate moderately severe airway obstruction. As the obstruction increases, tidal volume is maintained virtually to the point of exhaustion, at which time hypoxemia, hypercapnia, and acidosis progress rapidly, and cardiorespiratory arrest will soon follow unless the obstruction is relieved. Blood gases in children with respiratory obstruction demonstrate only mild hypoxemia21 until respiratory muscle exhaustion causes hypoventilation. Reliance should not be placed on blood gases in assessing the progress of respiratory obstruction, but where blood gases have been done and indicate hypoxemia and hypercapnia, the need for intervention is urgent. Assessment of the need for an artificial airway is based primarily on clinical signs. Scoring systems, advocated by some,18 are unreliable. Measurable signs (e. g., pulse rate, respiration rate) are of much less value than the child's general appearance to an experienced observer. Warning signs, in decreasing usefulness, are 1. A worried, unsettled appearance; restlessness, impression of deterioration, fatigue 2. Marked suprasternal, intercostal, and subcostal retraction on inspiration; marked use of accessory muscles of respiration 3. Increasing tachycardia
SEVERE UPPER AIRWAY OBSTRUCTION
Figure 1. Comparison of the normal neonatal nasopharynx and posterior choanae (left side) and bilateral posterior congenital choanal atresia (right side).
Figure 3. Acute epiglottitis due to H. inJluenzae showing the gross swelling and inflammation of the epiglottis and other supraglottic structures. In the right-hand photograph, a fairly small diameter endotracheal tube has been passed. It is noteworthy that the airway is not only through the lumen of the endotracheal tube, but the tube itself splints open and separates the swollen structures.
5
Figure 2. A case of croup with marked inflammatory subglottic edema on each side with a narrow anteroposterior slitlike residual lumen. The upper surface of the membranous vocal cords and the supraglottic structures appear normal.
Figure 4. An impacted subglottic foreign body (a piece of bone) with reactive granulation tissue in the anterior subglottic region. Note that there is no swelling of the vocal cords, and the airway obstruction is in the subglottic region.
I!
)
6
HENRY KILHA:v! ET AL.
Immediate preparation for "elective" intubation should be undertaken at this stage and proceeded with unless clear-cut improvement occurs. More urgent intervention is indicated by signs suggesting that respiratory failure is now present and that collapse is imminent: l. Markedly decreased respiratory effort, decreased stridor and breath sounds 2. Restless, distracted activity, decreased conscious level, hypotonia 3. Cyanosis or extreme pallor
Initial Hospital Management During assessment and prior to intubation, all children are continually observed but with minimal interference. Some children prefer to stay on their mother's lap; children usually are not separated from their parents until anesthesia for intubation is under way. The use of mist tents is adapted to the individual child, remembering that emotional distress from being placed in a tent will worsen the degree of airway obstruction and that the tent may hinder observation. Oxygen is used in those who show signs of hypoxia, although clinical evidence of hypoxia is considered a major indication for airway intervention. Those who are dehydrated receive intravenous fluids, but where the child appears well hydrated, placement of the intravenous cannula is often deferred until induction of anesthetic. Where the short delay involved is tolerable, nasotracheal intubation is performed in the operating room with an otolaryngologist in attendance. Anesthesia is induced using assisted ventilation with halothane and oxygen. A diagnosis of supraglottitis is made at laryngoscopy. Bronchoscopy with slim rigid telescopes is performed if a tracheal or esophageal foreign body is suspected, if tracheal pathology is suspected, or if the history and examination are unusual and do not fit well with acute laryngotracheobronchitis. Endotracheal tube size is very important. The tube should be large enough to provide an adequate airway but small enough to avoid added trauma. Suggested initial sizes are outlined in Table 4.
MANAGEMENT OF THE INTUBATED CHILD Following nasotracheal intubation, all children are nursed in a pediatric intensive care unit with 24 hours' availability of intensive care physicians and well-trained pediatric intensive care nurses. Humidification. During short-term intubation, inspired gases can be humidified by mist tents, circuits connected to humidifiers, or disposable
Table 4. Guide to Sizes of Endotracheal Tubes In Upper Airway Obstruction AGE
Preterm Neonatal Less than 6 months 6 Months-2 years 2 Years--5 years Greater than 5 years
INTERNAL DIAMETER
2.0 or 2.5 2.5 or 3.0 3.0 3.5 4.0
4.5
(mm)
SEVERE UPPER AIRWAY OBSTRUCTION
7
condenser humidifiers. Mist tents make nursing observation difficult and decrease child and parent contact. Circuit techniques increase the likelihood of accidental extubation. We have found that disposable condenser humidifiers allow for much greater acceptance by children and parents, and allow more mobility and normal childhood activity. 8 Condensers are changed every 8 hours, more frequently if there are copious thick tracheal secretions. Suctioning. Frequent and adequate suctioning with or without the instillation of normal saline is important to avoid tube blockage. The need for extremely frequent suctioning, particularly soon after intubation, may be due to the complication of pulmonary edema (see below). Endotracheal Tube. Accidental extubation is a major potential hazard. A chest x-ray is done soon after intubation to check tube position; the tube is secured by careful adhesive strapping to make accidental extubation unlikely. Fluids. All children with an endotracheal tube have an intravenous cannula in place. During short-term intubation, maintenah~e intravenous fluid volumes are given as glucose-saline solutions with added maintenance potassium (3 mEq per kg per day). For those likely to be intubated beyond 3 days, nasogastric enteral nutrition is commenced. Antibiotics. Children with supraglottitis are treated with chloramphenicol because of the local occurrence of ampicillin-resistant Haemophilus influenzae. In those children with suspected bacterial tracheitis, ampicillin and cloxacillin are given after Gram's stain and culture of tracheal aspirate, with subsequent appropriate changes based on culture findings. 15, 16, 19 Antibiotics are not given for uncomplicated laryngotracheobronchitis. Antibiotics may be given if chest opacities on x-rays suggest pneumonia is also present. General Care. Most children tolerate nasotracheal intubation remarkably well and sedation is rarely required, although initially armboards are employed to keep the arms extended. Children who are restless and difficult to control should be suspected of having a complication such as tracheal tube blockage, tube malposition, or hypoxia. Children should have as much access to their parents as possible; most parents welcome this opportunity to help their child. Activities appropriate to the child's age are commenced when possible. When to Extubate? Children with supraglotittis are extubated when they no longer have signs of toxicity and have minimal tracheal secretions on suctioning. A useful confirmatory test is their ability to sip fluids. This will generally be at about 24 hours (see Controversies in Management). In laryngotracheobronchitis, the presence of a leak around the tracheal tube should be assessed daily. If large, this will be obvious with the child coughing around the tube spontaneously or during suction. Otherwise, it is tested using positive pressure. If a leak becomes apparent and the child is afebrile and has minimal loose secretions, the tube is removed. The presence or absence of a leak is a variable sign, and if the child is otherwise well, even if a leak is not apparent at 7 days of intubation, extubation is performed. If extubation fails, the child is reintubated and endoscopy carried out. If, at endoscopy, there is necrosis or ulceration of the cartilage of the cricoid or posterior glottis secondary to intubation, a tracheotomy
8
HENRY KILHAM ET AL.
may be performed. If there is no significant ulceration and the pathology is that of early granulation tissue formation and subglottic edema, the child is reintubated for a further period of 3 to 7 days, preferably with a smaller tube. The average period of intubation for children with laryngotracheobronchitis is 4 to 5 days. Difficulties and Complications. Children who are intubated for upper airway obstruction often appear to be the easiest patients nursed in a pediatric intensive care unit. Their presence, however, tests the inherent efficiency and professionalism of any unit. Problems likely to be encountered include 1. Those associated with endotracheal tube complications, especially obstruction or displacement 2. The use of excessive sedation 3. The rare complication of pulmonary edema with either the presence or relief of upper airway obstruction. 28 This potentially fatal complication is usually adequately treated using intermittent positive-pressure ventilation with positive end-expiratory pressure (6-10 cm H 2 0) or sometimes with constant positive airway pressure alone (6-10 cms H 20). The pulmonary edema usually subsides in less than 24 hours but at times may require 4 to 5 days of treatment. 4. Psychosocial stresses to both the child and the parents. These can be minimized by constant communication with the parents, encouraging the parents to spend as much time as possible with their child during intubation, along with the competent professional care that will inspire confidence in both parents and children.
CONTROVERSIES IN MANAGEMENT These have been extensively reviewed 1• 6. 7. 9. 11. 20. 22 and therefore are only summarized here. Individual practices may reasonably vary according to available facilities, skills, and previous experience. (For impatient readers, abbreviated answers are given in parentheses.)
Do Lateral Airways Radiographs Assist in Management? (No) Good quality lateral airways radiograms will usually distinguish supraglottitis from croup and demonstrate radiodense foreign bodies. In supraglottitis, the appearance of the swollen epiglottis and aryepiglottic folds is quite characteristic but often misdiagnosed by inexperienced radiologists. The appearance of subglottic narrowing or haziness with a normal epiglottis satisfactorily excludes supraglottitis and helps to confirm a diagnosis of laryngotracheobronchitis. However, once severe airway obstruction is present, x-rays will cause undue delay in definitive treatment and may precipitate respiratory arrest, and should therefore not be taken. If in exceptional circumstances an x-ray appears necessary, a physician skilled in resuscitation must be present.
Should Corticosteroids Be Used in Severe Upper Airway Obstruction? (No) Despite extensive studies, 11. 17. 18.29 corticosteroids have not been shown to decrease the need for intervention in laryngotracheobronchitis or to
SEVERE UPPER AIRWAY OBSTRUCTION
9
otherwise favorably affect the course of the illness. Spasmodic croup is generally a milder condition, and it is hard to justify corticosteroids when benefit is marginal and when airway intervention is rarely required. In supraglottitis, bacterial tracheitis and diptheria, corticosteroids should not be used. Short-course, high-dose corticosteroids have been advocated for airway obstruction in infectious mononucleosis, an uncommon situation that affects mostly older children. 26 Benefits are controversial and airway intervention is usually not required whether corticosteroids are used, although their use may benefit the patient symptomatically. Corticosteroids have also been used in the hope of decreasing glottic and subglottic swelling following upper airway burns, with conflicting reports of efficacy. 5 A single large dose prior to extubation has been suggested to reduce tube-associated laryngeal swelling, but scientific support for this is lacking. Although shortcourse high-dose corticosteroid treatment would appear to be safe in croup, we feel drugs without proven benefits should generally not be used. Nastrocheal Tube or Tracheotomy? (Read on) Once intervention is needed, either procedure will produce excellent results but both have serious potential hazards. Tracheotomy has considerable morbidity and mortality except in skilled, practiced hands. The intubation period and hospital stay are usually considerably longer than with nasotracheal intubation. With nasotracheal intubation, the child must be expertly nursed in a well-equipped intensive care unit with physicians skilled in tube replacement constantly available; however, the nursing requirements following tracheotomy are no less stringent. Nasotracheal intubation is clearly superior for supraglottitis, providing that care during the period of intubationis adequate; this technique is now well-established also in the treatment of laryngotracheobronchitis. However, for optimal treatment, the option of an expertly performed tracheotomy must always be available. In diphtheria and laryngeal burns, early tracheotomy should be considered. Is There a Place for Nonintervention in Supraglottitis? (Rarely) A small minority of children with supraglottitis will experience only mild or moderate airway obstruction and quickly improve with antibiotic treatment. While successful treatment without intubation or tracheotomy of up to 30 per cent of children with this disease has been reported,24 one should never forget the highly unpredictable and dangerous nature of this condition with ever-present risks of death or serious hypoxic sequelae. In our view an intervention rate of 95 per cent, common to various hospitals, would appear quite appropriate. What Duration of Nasotracheal Intubation for Supraglottitis? (24 Hours) With extubation criteria as described above, almost all children can be extubated between 18 and 30 hours. While shorter periods (8-12 hours) have been reported without a high reintubation rate,23 24 hours would appear to be a safe compromise.
10
HENRY KILHAM ET AL.
Flexible or Solid Bronchoscopy? (Either or Neither) Detailed comparisons of these different techniques are reported elsewhere. 12. 25, 30 Modern rigid bronchoscopes and Hopkins telescopes achieve superb clarity and illumination, usually allow immediate removal of foreign bodies and allow more effective airway suctioning. Flexible bronchoscopes are adequate for diagnosis of most causes of upper airway obstruction and sometimes can be used to facilitate a difficult intubation in an older child. Safe, effective use of either technique demands special aptitudes, training, and constant practice; without these prerequisites these techniques should not be used. Diagnosis of common types of acute airway obstruction is usually confirmed at direct laryngoscopy; bronchoscopy seldom is needed. Endoscopy in neonatal airway obstruction is discussed further below. Has Nebulized Epinephrine or Racemic Epinephrine a Place in the Management of Croup? (A Qualified Yes) While these drugs can temporarily reduce upper airway obstruction in laryngotracheobronchitis or spasmodic croup, the relief is usually shortlived and even repeated use does not affect the duration or ultimate severity of the illness. 10, 13, 27 Children thus treated require meticulous supervision in a well-equipped emergency department or intensive care unit with the possible need for airways intervention always kept in mind. In our experience, epinephrine has been useful in children who have still required intubation but whose response to epinephrine has made transport from another hospital safer. What is the Best Artificial Airway for Emergency Use by the Inexperienced or Isolated Practitioner? (Read on) If a laryngoscope and an appropriately sized tracheal tube are available, and once desperate obstruction is present, use of such equipment by an inexperienced practitioner is still likely to be preferable to other methods or to further delay. Passing a short, wide-bore cannula through the cricothyroid membrane into the trachea is advocated by some. Emergency tracheotomy by a person with little or no experience with the technique has been successful on occasions, but a high associated morbidity and mortality must be expected. What is the Best Emergency Treatment for Obstructing Tonsillitis? (A Nasopharyngeal Tube) Acute tonsillitis superimposed on gross tonsillar hypertrophy is an important cause of severe upper airways obstruction. Passage of a nasopharyngeal tube can often be effective initial treatment in the emergency department or during transport between hospitals. However, at times, a tracheal tube will be necessary to overcome the obstruction; consideration must also be given to the use of penicillin, to treatment for cardiac failure if present, and to the possible need for early tonsillectomy and adenoidectomy.
SEVERE UPPER AIRWAY OBSTRUCTION
11
AIRWAY OBSTRUCTION IN THE NEWBORN Respiratory difficulty is common in the newborn period, but upper airway obstruction is only rarely the cause. It can result from a great variety of congenital abnormalities, or occasionally may result from trauma (Table 2). Associated abnormalities in the respiratory and other systems must always be suspected. Friedman et al. 12 showed that 10 per cent of patients may have lesions of more than one anatomic site in the upper aerodigestive tract. Holinger14 found that 45 per cent of patients undergoing diagnostic endoscopy for stridor had at least one other abnormality, mostly of the respiratory system. Clinical Features Significant features in the history may be elicited from parents, nursing attendants, pediatrician or neonatologist. Clues to upper airway problems include hydramnios, which can be associated with esophageal atresia, forceps delivery, or tracheal intubation with trauma. Physical signs of conditions associated with respiratory obstruction may be obvious at birth (e.g., micrognathia). Severe obstruction may be apparent immediately after birth, especially with bilateral choanal atresia, bilateral vocal cord paralysis, large congenital laryngeal cyst, or major laryngeal web. The severe stridor and cyanosis associated with total nasal obstruction may be momentarily relieved if the infant cries and takes a breath through the mouth, giving a clue to this type of obstruction. If both vocal cords are paralyzed, stridor is always present, the cry may be weak, and there is often aspiration of mucus. Other conditions obvious on examination include large neck masses such as hemangioma or lymphangioma, a large thyroglossal duct cyst, or a branchial cyst that may compress the pharynx or trachea. Major airway obstruction in the newborn baby produces stridor, evidenced by suprasternal, intercostal and subcostal retraction, sternal recession, tracheal tug, and Haring of the nasal alae during inspiration. With his or her limited respiratory muscle strength, the neonate will tire quickly with a high risk of cardiorespiratory arrest. A mumed or absent cry suggests supraglottic obstruction from a cyst or mass, unilateral vocal cord paresis or laryngeal web involving the vocal cords. A harsh barking cough or biphasic inspiratory stridor and expiratory wheeze, especially where there is retraction of the head and extension of the neck, suggests tracheal obstruction due to either compression (e.g., vascular ring) or collapse (e. g., tracheomalacia).3 Some congenital airway lesions do not present at birth. Examples include laryngomalacia (infantile larynx), in which stridor may appear from a few days to a few weeks after birth; vascular compression of the trachea, in which obstructive episodes may not occur for even months after birth; and subglottic hemangioma, in which symptoms may not appear for some weeks. 4 Although the clinical features may suggest the type of respiratory tract abnormality present, radiologic and endoscopic examinations are usually necessary to guide management.
I
12
HENRY KILHAM ET AL.
Table 5. Management of Airway Obstruction in the Newborn at the Children's Hospital, Sydney, Australia Severe respiratory distress Severe undiagnosed at birth due to respiratory respiratory difficulty obstruction: relieved by intubation
Intubate:",
~
I
Admit to a highdependency or intensive care unit for close
Maintain tracheal intubation and any other respiratory support necessary "'"
Recurring severe Mild or obstructive moderate airway episodes obstruction
_ _---------observation
If facilities for investigation
Assess need for investigation
and treatment are unavailable, transfer to an appropriate referral center"" Investigations:
~
~
Anteroposterior chest x-ray} Lateral airways x-ray Esophagogram as appropriate Bronchoscopy CT of chest mass Angiography
I
Where degree of obstruction remains severe, continue intubation, consider tracheotomy.
I
Arrange definitive surgical treatment, where indicated, at an appropriate time.
MANAGEMENT OF THE NEONATE WITH AIRWAY OBSTRUCTION As with older children, the first priority is maintaining an adequate airway while investigation and other treatment proceed. The plan summarized in Table 5 and discussed below is based on that used in our hospital. The infant who presents at birth with severe obstruction usually will require tracheal intubation as part of resuscitation. Neonates with increasing respiratory difficulty are assessed for the need for intervention as described above, remembering that they tire more rapidly, develop apnea unexpectedly, and often have lower respiratory disease as well. Severe cyanotic episodes with only mild intervening signs are occasionally seen. Management of the intubated neonate is similar to that for the infant and older child as discussed above. Radiologic Investigations Anteroposterior chest x-rays are done routinely. In infants who have not required intubation, an anteroposterior view of the tracheal air column using a high kilovolt technique to enhance the air column is useful (e. g., to demonstrate subglottic hemangioma or tracheal stenosis). A lateral study of the upper airways with x-ray or xeroradiograph
SEVERE UPPER AIRWAY OBSTRUCTION
13
is performed. 2 A well-exposed film with the patient's head and neck in the hyperextended position will consistently provide worthwhile information, often of essential diagnostic value, although experience is required to distinguish normal from abnormal and to interpret apparent abnormalities. Artifacts in x-rays of normal airways can be produced by bad positioning or poor exposure technique. An esophagogram is an essential investigation, in which vascular ring or other extrinsic tracheal compression is suspected. It can be carried out in an intubated child. A mediastinal mass, whether solid or cystic, is often best investigated with computed tomography (CT). Tracheobronchography is required only infrequently, for example, where congenital stenosis of the trachea requires further delineation. Angiocardiography may be needed to confirm presence of a vascular ring and to assist in planning of surgery. Endoscopy Whatever useful information is gained from physical and radiologic examinations, endoscopy is frequently necessary for definitive management. The neonatologist, respiratory physician, anesthesiologist and otolaryngologist work together as a team, determining the optimal time for endoscopy and making the procedure as safe as possible. Endoscopic examination of neonates is carried out under general anesthesia, using various endoscopic techniques to delineate, as necessary, the larynx, tracheobronchial tree, esophagus, nasal cavities, nasopharynx, and pharynx. Direct laryngoscopy without general anesthetic is inadequate. With cooperation and teamwork between the endoscopist and anesthesiologist, endoscopy is performed when necessary in infants weighing less than 1000 g. A full range of rigid endoscopes, Hopkins rod telescopes, and anesthetic and ancillary equipment is available. Our experience with flexible laryngoscopes and bronchoscopes is limited and we feel those in current use are less satisfactory than rigid, open-tube bronchoscopes. However, the new small diameter « 2 mm) flexible neonatalscopes may prove to have valuable application in the placement of endotracheal tubes and for localizing areas of obstruction. 25 Our experience indicates the need for cooperation between multiple disciplines. With these prerequisites, endoscopy can be highly informative with minimal morbidity. REFERENCES 1. Barker GA: Current management of croup and epiglottitis. Pediatr Clin North Am 26:565579, 1979 2. Benjamin B: Xeroradiography of the upper airways in paediatrics. Austr Radiol 23:214224, 1975 3. Benjamin B: Endoscopy in congenital tracheal anomalies. J Pediatr Surg 15:164-171,1980 4. Benjamin B, Carter P: Congenital laryngeal hemangioma. Ann Otol Rhinol Laryngol 92:448-455, 1983 5. Charnock EL, Meehan JJ: Postburn respiratory injuries in children. Pediatr Clin North Am 27:661-676, 1980 6. Cherry JD: The treatment of croup: Continued controversy due to failure of recognition of historic, ecologic, etiologic and clinical perspectives. J Pediatr 94:352-354, 1979 7. Davis HW, Gartner JC, Galvis AG, et al: Acute upper airway obstruction: Croup and epiglottitis. Pediatr Clin North Am 28:859-880, 1981
14
HENRY KILHAM ET AL.
8. Duncan A: Use of disposable condenser humidifiers in children. Anesth Intens Care 13:330, 1985 9. Duncan PG: Management of upper airway obstruction in children. Clin Crit Care Med 3:53-66, 1981 10. Fogel JM, Berg J, Gerber MA et al: Racemic epinephrine in the treatment of croup: Nebulization alone versus nebulization with intermittent positive pressure breathing. J Pediatr 101:1028-1031, 1982 11. Fried MP: Controversies in the management of supraglottitis and croup. Pediatr Clin North Am 26:931-942, 1979 12. Friedman EM, Williams M, Healy G et al: Pediatric endoscopy: A review of 616 cases. Ann Otol Rhinol Laryngol 93:517-521, 1984 13. Gardner HC, Powell KR, Roden VJ et al: The evaluation of racemic epinephrine in the treatment of infectious croup. Pediatrics 52:68-71, 1973 14. Holinger LD: Etiology of stridor in the neonate, infant and child. Ann Otol Rhinol Laryngol 89:397-400, 1980 15. Henry RL, Mellis CM, Benjamin B: Pseudomembranous croup. Arch Dis Child 58:180183, 1983 16. Jones R, Santos JK, Overall JC: Bacterial tracheitis. JAMA 242:721-726, 1979 17. Koren G, Fraud M, Barzilay Z et al: Corticosteroid treatment of laryngotracheitis v. spasmodic croup in children. Am J Dis Child 137:941-944, 1983 18. Leipzig B, Ostic FA, Cumming CW, et al: A prospective randomized study to determine the efficacy of steroids in the treatment of croup. J Pediatr 94:194-196, 1979 19. Liston SL, Gehrz RC, Siegel LG et al: Bacterial tracheitis. Am J Dis Child 137:764-767, 1983 20. Newth CJL: Acute epiglottitis and croup. In Nussbaum (ed): Pediatric Intensive Care. New York, E. Futura, 1984 21. Newth CJL, Levison H, Bryan AC: The respiratory status of children with croup. J Pediatr 81:1068-1073, 1972 22. Phelan PD, Landau LI, Olinsky A: Respiratory Illness in Children. Cambridge, Blackwell Scientific, 1982 23. Phelan PD, Mullins GC, Landau LI et al: The period of nasotracheal intubation in acute epiglottitis. Anesth Intens Care 8:402-403, 1980 24. Shann FA, Phelan PD, Stocks JG et al: Prolonged nasotracheal intubation or tracheostomy in acute laryngotracheobronchitis and epiglottis. Austr Paediatr J 11:212-217, 1975 25. Silberman HD, Tucker JA, Hempel A: Flexible neonatalscope. Ann Otol Rhinol Laryngol 93:468, 1984 26. Snyderman NL: Otorhinolaryngologic presentations of infectious mononucleosis. Pediatr Clin North Am 28:1011-1016, 1981 27. Taussig LM, Castro 0, Beadry PH et al: Treatment of laryngotracheobronchitis (croup). Am J Dis Child 129:790-793, 1975 28. Travis KW, Todres D, Shannon DC: Pulmonary edema associated with croup and epiglottitis. Pediatrics 59:695-698, 1977 29. Tunnessen WW, Feinstein AR: The steroid-croup controversy: An analytic review of methodologic problems. J Pediatr 96:751-756, 1980 30. Wood RE: Spelunking of the pediatric airways: Explorations with the flexible fiberoptic bronchoscope. Pediatr Clin North Am 31:785-799, 1984 The Children's Hospital Pyrmont Bridge Road Camperdown, Sydney NSW Australia 2050
0031-3955/87 $0.00
+ .20
Severe Upper Airway Obstruction Henry Kilham, MD, FRACP, * Jonathan Gillis, MD, FRACP, t and Bruce Benjamin, MD, FRACSt
"Whatever else you do, maintain an adequate airway!"
This article describes management of newborn and older children with severe upper airway obstruction, that is, those needing or likely to need airways support for their intact survival. These children have more to gain from optimal care, and more to lose from any error than most other children requiring admission to a pediatric intensive care unit. Special difficulties arise from delayed or incorrect diagnosis, rapid or unpredictable progression to respiratory failure, confusion over the value of investigations, and difficulty in assessing the need for an artificial airway. Intubation skills are critical. A child with severe airway obstruction will make obvious any organizational and procedural strengths and weakness in a hospital. Severe acute airway obstruction in infants and children is not uncommon. It has relatively few causes (Table 1), croup and supraglottitis predominating. Although the principal aim of management is to prevent hypoxemia and its damaging and potentially fatal consequences, practices vary widely. Each hospital must have clear-cut protocols and procedures to cope with the child with airway obstruction, taking into account available skills and facilities. Airway obstruction in the newborn is infrequent. Causes are numerous (Table 2), most of them congenital abnormalities. Subspecialty referral will often be necessary for diagnosis and treatment. A different approach is required for the newborn; this is described separately. More general reviews on croup and supraglottitis are already available. I, 7, 9, 20, 22 This review highlights the intensive care aspects of this problem. The management plan below is based on that used in the Children's Hospital, Sydney, Australia, a 320-bed referral teaching hospital serving a total population of 6 million. *StaH' PhYSician, Pediatric Intensive Care Unit tDirector of Intensive Care, Deputy Head, Department of Medicine tStaH' Physician, Pediatric Intensive Care Unit From The Royal Alexandra Hospital for Children, Camperdown, New South Wales, Australia
Pediatric Clinics of North America-Vol. 34, No.1, February 1987
1
2
HENRY KILHAM ET AL.
Table 1. Serious Acute Upper Airway Obstruction in the Infant and Child Infections Acute laryngotracheobronchitis Supraglottitis (epiglottitis) Diphtheria Bacterial tracheitis (pseudomembranous croup) Pharyngeal abscesses (e.g., retropharyngeal) Tonsillitis/tonsillar hypertrophy Accidents/trauma Glottic, subglottic, or esophageal foreign body External trauma to neck Burns to upper airway Iatrogenic Postintubation Postinstrumentation Others Angioedema Spasmodic croup Tumors (e.g., lymphoma in anterior mediastinum)
Table 2. Causes of Acute Upper Airway Obstruction in the Newborn Nasal cavity and nasopharynx Bilateral posterior choanal atresia* Fractured nose or deviated septum due to birth trauma Turbinate hypertrophy ("stuffY nose syndrome") Tumor (e.g., encephalocele, dermoid, chordoma, hematoma)* Facial skeletal abnormalities Pierre Robin syndrome (micrognathia, glossoptosis, cleft palate)* Treacher-Collins syndrome (mandibulofacial dysostosis)* Apert's syndrome (acrocephalosyndactyly)* Crouzon's syndrome (craniofacial dysostosis)* Oral cavity and oropharynx Macroglossia (primary and secondary) Aberrent thyroid tissue or internal thyroglossal duct cyst* Pharyngeal tumor (e.g., cystic hygroma, dermoid, hemangioma) Larynx Laryngomalacia ("infantile larynx") Bilateral vocal cord paralysis* Congenital subglottic stenosis* Congenital laryngeal web* Subglottic hemangioma Cystic obstruction Laryngeal papilloma Trachea Vascular ring compression (double aortic arch) Innominate artery compression *Conditions especially likely to cause early, severe obstruction.
·3
SEVERE UPPER AIRWAY OBSTRUCTION
SEVERE AIRWAY OBSTRUCTION IN THE INFANT AND OLDER CHILD Important Principles of Management 1. Ensuring an adequate airway, where necessary by tracheal intubation, takes precedence over any other diagnostic or therapeutic maneuver. 2. Conversely, unnecessary intervention will greatly increase distress at serious risk to the child. 3. Optimal management will result from combining the skills of the pediatrician, otolaryngologist, and pediatric anesthesiologist.
Sequence of events in management are summarized in Table 3. Possible etiologies are listed in Table 1. Etiology can often be determined from history and physical signs; other reviews 1 • 2. 7. 9. 20. 22 more comprehensively cover this aspect.
Table 3. Management of Upper Airway Obstruction at the Children's Hospital,
Sydney, Australia 1. Team consists of Emergency Department, residents, intensive care unit physicians, otolaryngology and anesthesiology staff members. 2. Children with Angioedema Severe upper airway obstruction I Suspected supraglottitis Page team Suspected foreign body inhalation urgently
CO~ing I I
Respiratory occurring now
Pog"
""'I
....,.,dy
Oxygenation and emergency intubation by fue most skilled individual available.
I
1
Failed intubation is extremely rare: [ emergency tracheotomy may fuen be "last resort"
I
Intensive care unit
I
[~;::;~~s::~ynaryngOSCOPYl only if diagnosis requires furtiIer elucidation.
I
adequately at this stage
Give humidified O2 , 1M epinephrine (0.01 mls per kg)
.;,,"mr ""m
Review need for further treatment: repeat epinephrine, intubation
Give humidified O2 by mask (parent and child to hold)
'"
Suspected laryngotracheobronchitis. Consider nebulized epinephrine.
Review need for intervention. If severe obstruction persists
/'
Take to operating room where condition permits use of O/halothane to allow a more controlled situation for intubation, limited endoscopic examination as necessary.
I
Intensive care unit
I
4
HENRY KILHAM ET AL.
The possibility of supraglottitis must always be kept in mind, as unpredictable progression to total obstruction is likely. Supraglottitis usually presents as a rapidly progressive illness with toxicity, fever, dysphagia, and drooling associated with upper airway obstruction. Cough is often not prominent; stridor is often soft and low-pitched and both voice and cry are muffled. Symptoms of toxicity may predominate so that the respiratory signs may be overlooked or misinterpreted as asthma or pneumonia. There is usually no difficulty differentiating supraglottitis from acute laryngotracheobronchitis with its barking cough, inspiratory stridor, and hoarseness. Differentiation between supraglottitis and bacterial tracheitis may be more difficult, the latter condition also often producing severe toxicity. Foreign body inhalation should always be considered if there is a history of a choking episode or unusual features in the history or clinical signs, for example, variable distress according to posture of asymmetric chest findings. The state of immunization should always be checked when considering diphtheria. Angioedema is more likely in preschool and school-aged children and is usually suggested by its associated swollen facial tissues and often urticaria. In essence, the important initial distinction is only between those who need either intubation or examination under anesthesia and those who require careful observation with more leisurely investigation. All of those patients who have 1. Suspected supraglottic pathology 2. Severe respiratory distress from upper airway obstruction 3. Suspected foreign body inhalation
should be taken to the operating theater, as outlined below. Assessing the Severity of Upper Airway Obstruction A previously healthy infant or child will readily tolerate moderately severe airway obstruction. As the obstruction increases, tidal volume is maintained virtually to the point of exhaustion, at which time hypoxemia, hypercapnia, and acidosis progress rapidly, and cardiorespiratory arrest will soon follow unless the obstruction is relieved. Blood gases in children with respiratory obstruction demonstrate only mild hypoxemia21 until respiratory muscle exhaustion causes hypoventilation. Reliance should not be placed on blood gases in assessing the progress of respiratory obstruction, but where blood gases have been done and indicate hypoxemia and hypercapnia, the need for intervention is urgent. Assessment of the need for an artificial airway is based primarily on clinical signs. Scoring systems, advocated by some,18 are unreliable. Measurable signs (e. g., pulse rate, respiration rate) are of much less value than the child's general appearance to an experienced observer. Warning signs, in decreasing usefulness, are 1. A worried, unsettled appearance; restlessness, impression of deterioration, fatigue 2. Marked suprasternal, intercostal, and subcostal retraction on inspiration; marked use of accessory muscles of respiration 3. Increasing tachycardia
SEVERE UPPER AIRWAY OBSTRUCTION
Figure 1. Comparison of the normal neonatal nasopharynx and posterior choanae (left side) and bilateral posterior congenital choanal atresia (right side).
Figure 3. Acute epiglottitis due to H. inJluenzae showing the gross swelling and inflammation of the epiglottis and other supraglottic structures. In the right-hand photograph, a fairly small diameter endotracheal tube has been passed. It is noteworthy that the airway is not only through the lumen of the endotracheal tube, but the tube itself splints open and separates the swollen structures.
5
Figure 2. A case of croup with marked inflammatory subglottic edema on each side with a narrow anteroposterior slitlike residual lumen. The upper surface of the membranous vocal cords and the supraglottic structures appear normal.
Figure 4. An impacted subglottic foreign body (a piece of bone) with reactive granulation tissue in the anterior subglottic region. Note that there is no swelling of the vocal cords, and the airway obstruction is in the subglottic region.
I!
)
6
HENRY KILHA:v! ET AL.
Immediate preparation for "elective" intubation should be undertaken at this stage and proceeded with unless clear-cut improvement occurs. More urgent intervention is indicated by signs suggesting that respiratory failure is now present and that collapse is imminent: l. Markedly decreased respiratory effort, decreased stridor and breath sounds 2. Restless, distracted activity, decreased conscious level, hypotonia 3. Cyanosis or extreme pallor
Initial Hospital Management During assessment and prior to intubation, all children are continually observed but with minimal interference. Some children prefer to stay on their mother's lap; children usually are not separated from their parents until anesthesia for intubation is under way. The use of mist tents is adapted to the individual child, remembering that emotional distress from being placed in a tent will worsen the degree of airway obstruction and that the tent may hinder observation. Oxygen is used in those who show signs of hypoxia, although clinical evidence of hypoxia is considered a major indication for airway intervention. Those who are dehydrated receive intravenous fluids, but where the child appears well hydrated, placement of the intravenous cannula is often deferred until induction of anesthetic. Where the short delay involved is tolerable, nasotracheal intubation is performed in the operating room with an otolaryngologist in attendance. Anesthesia is induced using assisted ventilation with halothane and oxygen. A diagnosis of supraglottitis is made at laryngoscopy. Bronchoscopy with slim rigid telescopes is performed if a tracheal or esophageal foreign body is suspected, if tracheal pathology is suspected, or if the history and examination are unusual and do not fit well with acute laryngotracheobronchitis. Endotracheal tube size is very important. The tube should be large enough to provide an adequate airway but small enough to avoid added trauma. Suggested initial sizes are outlined in Table 4.
MANAGEMENT OF THE INTUBATED CHILD Following nasotracheal intubation, all children are nursed in a pediatric intensive care unit with 24 hours' availability of intensive care physicians and well-trained pediatric intensive care nurses. Humidification. During short-term intubation, inspired gases can be humidified by mist tents, circuits connected to humidifiers, or disposable
Table 4. Guide to Sizes of Endotracheal Tubes In Upper Airway Obstruction AGE
Preterm Neonatal Less than 6 months 6 Months-2 years 2 Years--5 years Greater than 5 years
INTERNAL DIAMETER
2.0 or 2.5 2.5 or 3.0 3.0 3.5 4.0
4.5
(mm)
SEVERE UPPER AIRWAY OBSTRUCTION
7
condenser humidifiers. Mist tents make nursing observation difficult and decrease child and parent contact. Circuit techniques increase the likelihood of accidental extubation. We have found that disposable condenser humidifiers allow for much greater acceptance by children and parents, and allow more mobility and normal childhood activity. 8 Condensers are changed every 8 hours, more frequently if there are copious thick tracheal secretions. Suctioning. Frequent and adequate suctioning with or without the instillation of normal saline is important to avoid tube blockage. The need for extremely frequent suctioning, particularly soon after intubation, may be due to the complication of pulmonary edema (see below). Endotracheal Tube. Accidental extubation is a major potential hazard. A chest x-ray is done soon after intubation to check tube position; the tube is secured by careful adhesive strapping to make accidental extubation unlikely. Fluids. All children with an endotracheal tube have an intravenous cannula in place. During short-term intubation, maintenah~e intravenous fluid volumes are given as glucose-saline solutions with added maintenance potassium (3 mEq per kg per day). For those likely to be intubated beyond 3 days, nasogastric enteral nutrition is commenced. Antibiotics. Children with supraglottitis are treated with chloramphenicol because of the local occurrence of ampicillin-resistant Haemophilus influenzae. In those children with suspected bacterial tracheitis, ampicillin and cloxacillin are given after Gram's stain and culture of tracheal aspirate, with subsequent appropriate changes based on culture findings. 15, 16, 19 Antibiotics are not given for uncomplicated laryngotracheobronchitis. Antibiotics may be given if chest opacities on x-rays suggest pneumonia is also present. General Care. Most children tolerate nasotracheal intubation remarkably well and sedation is rarely required, although initially armboards are employed to keep the arms extended. Children who are restless and difficult to control should be suspected of having a complication such as tracheal tube blockage, tube malposition, or hypoxia. Children should have as much access to their parents as possible; most parents welcome this opportunity to help their child. Activities appropriate to the child's age are commenced when possible. When to Extubate? Children with supraglotittis are extubated when they no longer have signs of toxicity and have minimal tracheal secretions on suctioning. A useful confirmatory test is their ability to sip fluids. This will generally be at about 24 hours (see Controversies in Management). In laryngotracheobronchitis, the presence of a leak around the tracheal tube should be assessed daily. If large, this will be obvious with the child coughing around the tube spontaneously or during suction. Otherwise, it is tested using positive pressure. If a leak becomes apparent and the child is afebrile and has minimal loose secretions, the tube is removed. The presence or absence of a leak is a variable sign, and if the child is otherwise well, even if a leak is not apparent at 7 days of intubation, extubation is performed. If extubation fails, the child is reintubated and endoscopy carried out. If, at endoscopy, there is necrosis or ulceration of the cartilage of the cricoid or posterior glottis secondary to intubation, a tracheotomy
8
HENRY KILHAM ET AL.
may be performed. If there is no significant ulceration and the pathology is that of early granulation tissue formation and subglottic edema, the child is reintubated for a further period of 3 to 7 days, preferably with a smaller tube. The average period of intubation for children with laryngotracheobronchitis is 4 to 5 days. Difficulties and Complications. Children who are intubated for upper airway obstruction often appear to be the easiest patients nursed in a pediatric intensive care unit. Their presence, however, tests the inherent efficiency and professionalism of any unit. Problems likely to be encountered include 1. Those associated with endotracheal tube complications, especially obstruction or displacement 2. The use of excessive sedation 3. The rare complication of pulmonary edema with either the presence or relief of upper airway obstruction. 28 This potentially fatal complication is usually adequately treated using intermittent positive-pressure ventilation with positive end-expiratory pressure (6-10 cm H 2 0) or sometimes with constant positive airway pressure alone (6-10 cms H 20). The pulmonary edema usually subsides in less than 24 hours but at times may require 4 to 5 days of treatment. 4. Psychosocial stresses to both the child and the parents. These can be minimized by constant communication with the parents, encouraging the parents to spend as much time as possible with their child during intubation, along with the competent professional care that will inspire confidence in both parents and children.
CONTROVERSIES IN MANAGEMENT These have been extensively reviewed 1• 6. 7. 9. 11. 20. 22 and therefore are only summarized here. Individual practices may reasonably vary according to available facilities, skills, and previous experience. (For impatient readers, abbreviated answers are given in parentheses.)
Do Lateral Airways Radiographs Assist in Management? (No) Good quality lateral airways radiograms will usually distinguish supraglottitis from croup and demonstrate radiodense foreign bodies. In supraglottitis, the appearance of the swollen epiglottis and aryepiglottic folds is quite characteristic but often misdiagnosed by inexperienced radiologists. The appearance of subglottic narrowing or haziness with a normal epiglottis satisfactorily excludes supraglottitis and helps to confirm a diagnosis of laryngotracheobronchitis. However, once severe airway obstruction is present, x-rays will cause undue delay in definitive treatment and may precipitate respiratory arrest, and should therefore not be taken. If in exceptional circumstances an x-ray appears necessary, a physician skilled in resuscitation must be present.
Should Corticosteroids Be Used in Severe Upper Airway Obstruction? (No) Despite extensive studies, 11. 17. 18.29 corticosteroids have not been shown to decrease the need for intervention in laryngotracheobronchitis or to
SEVERE UPPER AIRWAY OBSTRUCTION
9
otherwise favorably affect the course of the illness. Spasmodic croup is generally a milder condition, and it is hard to justify corticosteroids when benefit is marginal and when airway intervention is rarely required. In supraglottitis, bacterial tracheitis and diptheria, corticosteroids should not be used. Short-course, high-dose corticosteroids have been advocated for airway obstruction in infectious mononucleosis, an uncommon situation that affects mostly older children. 26 Benefits are controversial and airway intervention is usually not required whether corticosteroids are used, although their use may benefit the patient symptomatically. Corticosteroids have also been used in the hope of decreasing glottic and subglottic swelling following upper airway burns, with conflicting reports of efficacy. 5 A single large dose prior to extubation has been suggested to reduce tube-associated laryngeal swelling, but scientific support for this is lacking. Although shortcourse high-dose corticosteroid treatment would appear to be safe in croup, we feel drugs without proven benefits should generally not be used. Nastrocheal Tube or Tracheotomy? (Read on) Once intervention is needed, either procedure will produce excellent results but both have serious potential hazards. Tracheotomy has considerable morbidity and mortality except in skilled, practiced hands. The intubation period and hospital stay are usually considerably longer than with nasotracheal intubation. With nasotracheal intubation, the child must be expertly nursed in a well-equipped intensive care unit with physicians skilled in tube replacement constantly available; however, the nursing requirements following tracheotomy are no less stringent. Nasotracheal intubation is clearly superior for supraglottitis, providing that care during the period of intubationis adequate; this technique is now well-established also in the treatment of laryngotracheobronchitis. However, for optimal treatment, the option of an expertly performed tracheotomy must always be available. In diphtheria and laryngeal burns, early tracheotomy should be considered. Is There a Place for Nonintervention in Supraglottitis? (Rarely) A small minority of children with supraglottitis will experience only mild or moderate airway obstruction and quickly improve with antibiotic treatment. While successful treatment without intubation or tracheotomy of up to 30 per cent of children with this disease has been reported,24 one should never forget the highly unpredictable and dangerous nature of this condition with ever-present risks of death or serious hypoxic sequelae. In our view an intervention rate of 95 per cent, common to various hospitals, would appear quite appropriate. What Duration of Nasotracheal Intubation for Supraglottitis? (24 Hours) With extubation criteria as described above, almost all children can be extubated between 18 and 30 hours. While shorter periods (8-12 hours) have been reported without a high reintubation rate,23 24 hours would appear to be a safe compromise.
10
HENRY KILHAM ET AL.
Flexible or Solid Bronchoscopy? (Either or Neither) Detailed comparisons of these different techniques are reported elsewhere. 12. 25, 30 Modern rigid bronchoscopes and Hopkins telescopes achieve superb clarity and illumination, usually allow immediate removal of foreign bodies and allow more effective airway suctioning. Flexible bronchoscopes are adequate for diagnosis of most causes of upper airway obstruction and sometimes can be used to facilitate a difficult intubation in an older child. Safe, effective use of either technique demands special aptitudes, training, and constant practice; without these prerequisites these techniques should not be used. Diagnosis of common types of acute airway obstruction is usually confirmed at direct laryngoscopy; bronchoscopy seldom is needed. Endoscopy in neonatal airway obstruction is discussed further below. Has Nebulized Epinephrine or Racemic Epinephrine a Place in the Management of Croup? (A Qualified Yes) While these drugs can temporarily reduce upper airway obstruction in laryngotracheobronchitis or spasmodic croup, the relief is usually shortlived and even repeated use does not affect the duration or ultimate severity of the illness. 10, 13, 27 Children thus treated require meticulous supervision in a well-equipped emergency department or intensive care unit with the possible need for airways intervention always kept in mind. In our experience, epinephrine has been useful in children who have still required intubation but whose response to epinephrine has made transport from another hospital safer. What is the Best Artificial Airway for Emergency Use by the Inexperienced or Isolated Practitioner? (Read on) If a laryngoscope and an appropriately sized tracheal tube are available, and once desperate obstruction is present, use of such equipment by an inexperienced practitioner is still likely to be preferable to other methods or to further delay. Passing a short, wide-bore cannula through the cricothyroid membrane into the trachea is advocated by some. Emergency tracheotomy by a person with little or no experience with the technique has been successful on occasions, but a high associated morbidity and mortality must be expected. What is the Best Emergency Treatment for Obstructing Tonsillitis? (A Nasopharyngeal Tube) Acute tonsillitis superimposed on gross tonsillar hypertrophy is an important cause of severe upper airways obstruction. Passage of a nasopharyngeal tube can often be effective initial treatment in the emergency department or during transport between hospitals. However, at times, a tracheal tube will be necessary to overcome the obstruction; consideration must also be given to the use of penicillin, to treatment for cardiac failure if present, and to the possible need for early tonsillectomy and adenoidectomy.
SEVERE UPPER AIRWAY OBSTRUCTION
11
AIRWAY OBSTRUCTION IN THE NEWBORN Respiratory difficulty is common in the newborn period, but upper airway obstruction is only rarely the cause. It can result from a great variety of congenital abnormalities, or occasionally may result from trauma (Table 2). Associated abnormalities in the respiratory and other systems must always be suspected. Friedman et al. 12 showed that 10 per cent of patients may have lesions of more than one anatomic site in the upper aerodigestive tract. Holinger14 found that 45 per cent of patients undergoing diagnostic endoscopy for stridor had at least one other abnormality, mostly of the respiratory system. Clinical Features Significant features in the history may be elicited from parents, nursing attendants, pediatrician or neonatologist. Clues to upper airway problems include hydramnios, which can be associated with esophageal atresia, forceps delivery, or tracheal intubation with trauma. Physical signs of conditions associated with respiratory obstruction may be obvious at birth (e.g., micrognathia). Severe obstruction may be apparent immediately after birth, especially with bilateral choanal atresia, bilateral vocal cord paralysis, large congenital laryngeal cyst, or major laryngeal web. The severe stridor and cyanosis associated with total nasal obstruction may be momentarily relieved if the infant cries and takes a breath through the mouth, giving a clue to this type of obstruction. If both vocal cords are paralyzed, stridor is always present, the cry may be weak, and there is often aspiration of mucus. Other conditions obvious on examination include large neck masses such as hemangioma or lymphangioma, a large thyroglossal duct cyst, or a branchial cyst that may compress the pharynx or trachea. Major airway obstruction in the newborn baby produces stridor, evidenced by suprasternal, intercostal and subcostal retraction, sternal recession, tracheal tug, and Haring of the nasal alae during inspiration. With his or her limited respiratory muscle strength, the neonate will tire quickly with a high risk of cardiorespiratory arrest. A mumed or absent cry suggests supraglottic obstruction from a cyst or mass, unilateral vocal cord paresis or laryngeal web involving the vocal cords. A harsh barking cough or biphasic inspiratory stridor and expiratory wheeze, especially where there is retraction of the head and extension of the neck, suggests tracheal obstruction due to either compression (e.g., vascular ring) or collapse (e. g., tracheomalacia).3 Some congenital airway lesions do not present at birth. Examples include laryngomalacia (infantile larynx), in which stridor may appear from a few days to a few weeks after birth; vascular compression of the trachea, in which obstructive episodes may not occur for even months after birth; and subglottic hemangioma, in which symptoms may not appear for some weeks. 4 Although the clinical features may suggest the type of respiratory tract abnormality present, radiologic and endoscopic examinations are usually necessary to guide management.
I
12
HENRY KILHAM ET AL.
Table 5. Management of Airway Obstruction in the Newborn at the Children's Hospital, Sydney, Australia Severe respiratory distress Severe undiagnosed at birth due to respiratory respiratory difficulty obstruction: relieved by intubation
Intubate:",
~
I
Admit to a highdependency or intensive care unit for close
Maintain tracheal intubation and any other respiratory support necessary "'"
Recurring severe Mild or obstructive moderate airway episodes obstruction
_ _---------observation
If facilities for investigation
Assess need for investigation
and treatment are unavailable, transfer to an appropriate referral center"" Investigations:
~
~
Anteroposterior chest x-ray} Lateral airways x-ray Esophagogram as appropriate Bronchoscopy CT of chest mass Angiography
I
Where degree of obstruction remains severe, continue intubation, consider tracheotomy.
I
Arrange definitive surgical treatment, where indicated, at an appropriate time.
MANAGEMENT OF THE NEONATE WITH AIRWAY OBSTRUCTION As with older children, the first priority is maintaining an adequate airway while investigation and other treatment proceed. The plan summarized in Table 5 and discussed below is based on that used in our hospital. The infant who presents at birth with severe obstruction usually will require tracheal intubation as part of resuscitation. Neonates with increasing respiratory difficulty are assessed for the need for intervention as described above, remembering that they tire more rapidly, develop apnea unexpectedly, and often have lower respiratory disease as well. Severe cyanotic episodes with only mild intervening signs are occasionally seen. Management of the intubated neonate is similar to that for the infant and older child as discussed above. Radiologic Investigations Anteroposterior chest x-rays are done routinely. In infants who have not required intubation, an anteroposterior view of the tracheal air column using a high kilovolt technique to enhance the air column is useful (e. g., to demonstrate subglottic hemangioma or tracheal stenosis). A lateral study of the upper airways with x-ray or xeroradiograph
SEVERE UPPER AIRWAY OBSTRUCTION
13
is performed. 2 A well-exposed film with the patient's head and neck in the hyperextended position will consistently provide worthwhile information, often of essential diagnostic value, although experience is required to distinguish normal from abnormal and to interpret apparent abnormalities. Artifacts in x-rays of normal airways can be produced by bad positioning or poor exposure technique. An esophagogram is an essential investigation, in which vascular ring or other extrinsic tracheal compression is suspected. It can be carried out in an intubated child. A mediastinal mass, whether solid or cystic, is often best investigated with computed tomography (CT). Tracheobronchography is required only infrequently, for example, where congenital stenosis of the trachea requires further delineation. Angiocardiography may be needed to confirm presence of a vascular ring and to assist in planning of surgery. Endoscopy Whatever useful information is gained from physical and radiologic examinations, endoscopy is frequently necessary for definitive management. The neonatologist, respiratory physician, anesthesiologist and otolaryngologist work together as a team, determining the optimal time for endoscopy and making the procedure as safe as possible. Endoscopic examination of neonates is carried out under general anesthesia, using various endoscopic techniques to delineate, as necessary, the larynx, tracheobronchial tree, esophagus, nasal cavities, nasopharynx, and pharynx. Direct laryngoscopy without general anesthetic is inadequate. With cooperation and teamwork between the endoscopist and anesthesiologist, endoscopy is performed when necessary in infants weighing less than 1000 g. A full range of rigid endoscopes, Hopkins rod telescopes, and anesthetic and ancillary equipment is available. Our experience with flexible laryngoscopes and bronchoscopes is limited and we feel those in current use are less satisfactory than rigid, open-tube bronchoscopes. However, the new small diameter « 2 mm) flexible neonatalscopes may prove to have valuable application in the placement of endotracheal tubes and for localizing areas of obstruction. 25 Our experience indicates the need for cooperation between multiple disciplines. With these prerequisites, endoscopy can be highly informative with minimal morbidity. REFERENCES 1. Barker GA: Current management of croup and epiglottitis. Pediatr Clin North Am 26:565579, 1979 2. Benjamin B: Xeroradiography of the upper airways in paediatrics. Austr Radiol 23:214224, 1975 3. Benjamin B: Endoscopy in congenital tracheal anomalies. J Pediatr Surg 15:164-171,1980 4. Benjamin B, Carter P: Congenital laryngeal hemangioma. Ann Otol Rhinol Laryngol 92:448-455, 1983 5. Charnock EL, Meehan JJ: Postburn respiratory injuries in children. Pediatr Clin North Am 27:661-676, 1980 6. Cherry JD: The treatment of croup: Continued controversy due to failure of recognition of historic, ecologic, etiologic and clinical perspectives. J Pediatr 94:352-354, 1979 7. Davis HW, Gartner JC, Galvis AG, et al: Acute upper airway obstruction: Croup and epiglottitis. Pediatr Clin North Am 28:859-880, 1981
14
HENRY KILHAM ET AL.
8. Duncan A: Use of disposable condenser humidifiers in children. Anesth Intens Care 13:330, 1985 9. Duncan PG: Management of upper airway obstruction in children. Clin Crit Care Med 3:53-66, 1981 10. Fogel JM, Berg J, Gerber MA et al: Racemic epinephrine in the treatment of croup: Nebulization alone versus nebulization with intermittent positive pressure breathing. J Pediatr 101:1028-1031, 1982 11. Fried MP: Controversies in the management of supraglottitis and croup. Pediatr Clin North Am 26:931-942, 1979 12. Friedman EM, Williams M, Healy G et al: Pediatric endoscopy: A review of 616 cases. Ann Otol Rhinol Laryngol 93:517-521, 1984 13. Gardner HC, Powell KR, Roden VJ et al: The evaluation of racemic epinephrine in the treatment of infectious croup. Pediatrics 52:68-71, 1973 14. Holinger LD: Etiology of stridor in the neonate, infant and child. Ann Otol Rhinol Laryngol 89:397-400, 1980 15. Henry RL, Mellis CM, Benjamin B: Pseudomembranous croup. Arch Dis Child 58:180183, 1983 16. Jones R, Santos JK, Overall JC: Bacterial tracheitis. JAMA 242:721-726, 1979 17. Koren G, Fraud M, Barzilay Z et al: Corticosteroid treatment of laryngotracheitis v. spasmodic croup in children. Am J Dis Child 137:941-944, 1983 18. Leipzig B, Ostic FA, Cumming CW, et al: A prospective randomized study to determine the efficacy of steroids in the treatment of croup. J Pediatr 94:194-196, 1979 19. Liston SL, Gehrz RC, Siegel LG et al: Bacterial tracheitis. Am J Dis Child 137:764-767, 1983 20. Newth CJL: Acute epiglottitis and croup. In Nussbaum (ed): Pediatric Intensive Care. New York, E. Futura, 1984 21. Newth CJL, Levison H, Bryan AC: The respiratory status of children with croup. J Pediatr 81:1068-1073, 1972 22. Phelan PD, Landau LI, Olinsky A: Respiratory Illness in Children. Cambridge, Blackwell Scientific, 1982 23. Phelan PD, Mullins GC, Landau LI et al: The period of nasotracheal intubation in acute epiglottitis. Anesth Intens Care 8:402-403, 1980 24. Shann FA, Phelan PD, Stocks JG et al: Prolonged nasotracheal intubation or tracheostomy in acute laryngotracheobronchitis and epiglottis. Austr Paediatr J 11:212-217, 1975 25. Silberman HD, Tucker JA, Hempel A: Flexible neonatalscope. Ann Otol Rhinol Laryngol 93:468, 1984 26. Snyderman NL: Otorhinolaryngologic presentations of infectious mononucleosis. Pediatr Clin North Am 28:1011-1016, 1981 27. Taussig LM, Castro 0, Beadry PH et al: Treatment of laryngotracheobronchitis (croup). Am J Dis Child 129:790-793, 1975 28. Travis KW, Todres D, Shannon DC: Pulmonary edema associated with croup and epiglottitis. Pediatrics 59:695-698, 1977 29. Tunnessen WW, Feinstein AR: The steroid-croup controversy: An analytic review of methodologic problems. J Pediatr 96:751-756, 1980 30. Wood RE: Spelunking of the pediatric airways: Explorations with the flexible fiberoptic bronchoscope. Pediatr Clin North Am 31:785-799, 1984 The Children's Hospital Pyrmont Bridge Road Camperdown, Sydney NSW Australia 2050