Indian Journal of Anaesthesia 2008; 52 (3):273-281

Special Article

Approach to Difficult and Compromised Airway in Neonatal and Paediatric Age Group Patients Mona Vashist1, H P S Miglani2

Summary One of the greatest challenge to the anaesthesiologists is management of child with difficult airway. Sometimes serious anaesthetic accidents have occurred due to mismanagement of airway. Management of even normal airway in a neonate is different and complex as compared to airway of two year old child and that of adult. Airway management of neonates and babies with difficult and compromised airway is being discussed. Key words

Neonatal; Respiratory distress; Compromised airway.

Introduction

Difficult airway

The child differs from adult in many ways both in size, shape and position of airways as well as in the airway epithelium and its supporting structures. As the baby grows, normal airway becomes easy to handle, but in conditions of abnormal airway difficulties may grow with child.

Definition of the difficult airway is related solely to tracheal intubation or problems with mask ventilation1. Central to the management must be an understanding of the anatomical, biochemical or pathophysiological mechanism responsible for airway complications. In approaching the difficult airway2, it is useful to consider the following broad categories.

The most common cause of mortality and series morbidity due to anaesthesia is from airway problems. It is estimated that about 1/3rd of all anaesthetic deaths in neonates and children are due to failure to intubate and ventilate. The major responsibility of anaesthetist is to provide adequate ventilation to the baby (Fig.1).

1. Previous history of difficulty or failure in establishing control and access to patient’s airway. 2. Presence of anatomical or physiological pathology which might predictably be associated with difficulty in airway management. 3. Limited experience in evaluating planning and management the difficult airway. Airway of infant differs in following ways from that of adults 1. Upper airway of the infant is smaller than that of adult. 2. Relatively large size of infant’s head tends to flex the short neck and obstruct the airway. 3. Relatively large size of infant’s tongue in relation to oropharynx increases the likelihood of airway ob-

Fig 1 Anatomy of normal airway

1. Associate Professor, 2. Professor of Paediatric Surgery, Department of Anaesthesia and Intensive Care, Sri Guru Ram Dass Institute of Medical Sciences and Research Center, Amritsar. Correspondence to: Mona Vashist, F-1, 418, Mata Kaulan Marg, Kashmir, Avenue, Amritsar – 143001, Email:[email protected] Accepted for publication on: 23.4.08 273

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4.

5. 6.

7.

struction and technical difficulties during laryngoscopy. Epiglottis is shaped differently being short and stubby, and is angled over laryngeal inlet. Control with the laryngoscope blade is therefore more difficult. Larynx is located higher in the neck thus making the straight blades more useful than curved blades. Infant larynx is funnel shaped, narrowest portion occuring at the cricoid cartilage in children below 8 years of age. -Cricoid ring which is complete may not accept a tracheal tube which was passed through glottis. -Minimal oedema of cricoid ring may reduce the airway by 70% in the neonate. Vocal cords are angled, so that a “blindly” passed endotracheal tube may easily lodge in the anterior commissure rather than slide into the trachea.

Evaluation of difficult neonatal and paediatric airway History of apnea, stridor, day time sleep, snoring (may be indicative of airway obstruction, that can be exaggerated by induction). History should also consist of review of previous anaesthetic records with attention being paid to history of oropharyngeal injury, damage to teeth, postponement of surgery after anaesthetic exposure. Physical examination includes: • • • • • •

Compromised airway

Evaluation of size and shape of head. Gross facial features. Size and symmetry of mandible. Size of tongue. Prominence of upper incisors. Range of motion in jaw and head and neck.

A number of bed-side tests have been proposed to assess difficult airway in adults. Thyromental distance by Patil and colleagues. Visual examination of the posterior wall of the pharynx by mallampatti. But the commonly used assessment criteria have not been valid for small babies and even mouth opening, neck and jaw mobility are difficult to assess in non-cooperative child4.

Compromise of the airway implies3 partial obstruction to airflow and constant threat to the total obstruction if relaxation of the muscles of the upper airway narrows the air passages. These babies when present with airway obstruction, require urgent and expert management to avoid mortality and morbidity.

Prediction of difficult airway by Samson and young’s5,6 modification of Mallampati classification of 476 children between 0-16 years suggested an inaccurate prediction of peer view during direct laryngoscopy. The assessment is hampered by lack of co-operation in infants and young children. No control trials are available for evaluation of mandibular space, neck mobility and jaw movements to predict difficult laryngoscopy in paediatric population. Thus measurement of mentohyoid, thyromental, mandibular and interdental length have no value to predict difficult airway in paediatric patients.

Airway obstruction that is severe or prolonged or has bouts of near total obstruction may be fatal or result in permanent neurological damage from cerebral hypoxia or intraventricular haemorrhage. Clinical signs of airway obstruction in babies with compromised airway are stridor, intercostal indrawing, chest recession. The hurried irregular respiration and apnoeic attacks with intermittent cyanosis, bradycardia with peripheral circulatory failure may lead to irreversible brain damage. Causes of compromised and difficult airway in the newborn can be congenital and acquired.

Causes of difficult airway 274

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1)

poplasia which keeps the tongue high in the oral cavity causing cleft in the palate by preventing closure of palatal shelves and causing cleft palate. Mandibular hypoplasia resolves and child obtains normal profile by 5-6 years of age.

Cranio facial anomaly - Pierre Robin Syndrome - Treacher Collin’s syndrome - Goldenhar Syndrome

2)

Cervical spine:- Down Syndrome - Klippel Feil Syndrome

3)

Structural - Mucopolysaccharidosis - Post burns contracture - Trauma - Temporomandibular joint ankylosis.

4)

Inflammatory - Retropharyngeal abscess - Laryngeal papilomatosis. - Acute epiglottitis

5)

Fig 2 Neonate with Pierre robin syndrome

Neoplastic - Cystic hygroma

These neonates should be nursed in the prone position. If this fails to relieve the respiratory obstruction nasopharyngeal airway/endotracheal intubation should be done to protect the airway. If intubation is not possible, tracheostomy may be done to secure the airway as sometimes even fiberoptic bronchoscopic intubation can be unsuccessful because of narrow anatomical conditions. LMA is a good alternative for these type of babies.

- Encephalocele - Meningo myelocele

Causes of compromised airway 1. Bilateral choanal atresia 2. Subglottic stenosis 3. Tracheo malacia 4. Foreign body in air passage 5. Ludwig’s angina

These babies may need surgery for tongue tie or cleft palatal repair. Inhalational induction with spontaneous breathing is the suitable method to secure the airway.

6. Acute epiglottitis 7. Trauma

1.

Pierre Robin Syndrome (Fig.2)

2. Treacher Collins Syndrome

It is a rare syndrome with micrognathia7,8 and posterior displacement of tongue (glossoptosis) causing airway obstruction in the neonate, failure to thrive. Other congenital anomalies associated can be cleft palate, oesophageal atresia and eye problems.

Mandibulofacial dysostosis, microgonathia, malar hypoplasia, cleft palate, congenital heart disease (VSD). Associated with extremely difficult intubation.

3. Goldenhar syndrome

Oesophageal atresia, eye anomalies and oligohydroamnios could play a role in mandibular hy-

It is a rare9 (1 in every 3500 to 1 in 5600 live 275

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Assisted spontaneous ventilation till the intubation is possible. Maintaining spontaneous gas exchange benefits in two ways:

births) congenital hemicraniofacial dysmorphology and is often associated with difficult intubation. A distorted face is a reliable guide to the potential of airway problems. The aetiology remains unclear. Development defects of first and second branchial arches during foetal development causes such type of deformity. Intubation at the time of anaesthesia can be difficult because of combination of a small, asymetric jaw and limited neck motion.

4. Mucopolysaccharidosis

Fig 3 Servere burns making the airway compromised and a case of difficult intubation

MPS are hereditary progressive disorders10,11 caused by excessive intra lysosomal accumulation of glycosaminoglycans in various tissues. The intracellular accumulation of glycosaminoglycans causes cellular enlargement with resultant disruption of the structure and functions of tissue involved. Multiple factors are present in MPS which make airway management and tracheal intubation potentially hazardous. In addition to generalised infiltration and thickening of soft tissue, oropharynx may be obstructed by large tongue with or without tonsillar hypertrophy. The nasal airway is also narrowed by thickened mucous membrane, adenoid hypertrophy and reduntant granulomatous tissue.

a. Protects against total airway obstruction due to loss of upper airway muscle tone. b. Spontaneous breath sounds may act as valuable guide to locate the glottis.

6. TMJ ankylosis It is a known cause of difficult13 intubation because of restricted mouth opening and altered jaw anatomy.

7. Retropharyngeal abscess It is postentially life threatening14,15 condition as rupture of abscess can result in pulmonary aspiration and under anaesthesia, inability to secure the airway due to blood, pus and secretions. Baby may not have symptoms of airway obstruction in awake state but can manifest under anaesthesia with muscle relaxation. Thus inhalation induction of anaesthesia should be the right choice in spontaneously breathing baby. Head low position with lateral tilt and use of transparent mask are helpful to detect and prevent aspiration during intubation. Even inability to ventilate inspite of securing airway under direct vision can cause unforeseen challenges. The surgical airway should always be kept ready which can be life saving in such circumstances.

Neck is typically short, immobile. Cervical spine and TM joint may have limited range of movement. Trachea is often narrow and flattened. The uniqueness of the airway and extreme sensitive airway often result in failure of intubation and bronchospasm even after successful intubation. The older the patient greater are the problems due to progressive nature of disease.

5. Burns (Fig.3) Burns of the head and neck area and inhalation burn injuries may cause severe airway compromise due to massive oedema12. Best course of action is to intubate and ventilate without delay. Later complications of burn injuries include hypertrophic scars and contractures. Neck contractures make airway, further difficult as it impairs neck extension thus make glottic visualization difficult.

8. Laryngeal papilloma Papillomas of larynx are benign, warty growth that are difficult to treat. 276

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Laryngeal papillomas, the most common laryngeal neoplasm in children. Human papilloma virus 6,11,16 have been implicated as the causative agent. A substantial percentage of mother of babies with laryngeal papillomas have history of genital condyloma. At the time of delivery this virus may be acquired by the baby during passage through the infected birth canal. After age at onset is 2-4 years, babies develop hoarseness, croupy cough, stridor that may lead to fatal airway obstruction. Diagnosis is confirmed by direct laryngoscopy. Management involves relieving the airway obstruction by surgical removal of the lesion. Tracheostomy is necessary when life threatening obstruction occurs. Various surgical procedures have been used to treat papillomas but recurrences are the rule and frequently reoperation may be needed. The lesions spread down the trachea and bronchii, thereby making surgical removal more difficult. Fortunately spontaneous remissions do occur usually by puberty, so that goal of therapy is to maintain an adequate airway until remission occurs.

Fig 4 Case of cystic hygroma leading to difficult airway

9. Cystic hygroma (Fig.4)

Fig 5 Showing huge occipital encephalocele

It is benign cystic hamartoma of lymphatic system. Multiple cystic cavities filled with clear and straw coloured fluid. Majority of hygroma do not cause intubation difficulty, some times may become difficult to intubate that may require tracheostomy16.

cephaly. Associated common congenital anomalies are: 1. Myelomeningocele 2. Klippel-Feil abnormality

10. Occipital encephalocele (Fig.5)

3. Congenital heart disease

It is a neural tube deformity 17 related to anancephaly and spina bifida. The cranial defects occur 1/10th as commonly as the spinal ones and are associated with circular/oval defects in the occipital bone.

4. Duodenal atresia 5. Anorectal malformation 6. Cystic disease of kidney and pancreas 7. Klippel Feil abnormality produces intubation difficulty

The lesions may very from quite small skin covered nodule to very large cystic swelling bigger than the neonate’s head. The covering is sometimes quiet thin, being on the verge of rupture. Both types usually contain brain tissue, either cerebellum or part of occipital lobe and are frequently associated with micro-

The presence of huge occipital encephalocele18 adds to intubation difficulty. Laryngoscopy, intubation and airway management, become difficult in the supine position due to large occipi12tal encephalocele. 277

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Awake intubation in the right lateral position can be done to overcome the problem. Since19 awake intubation has the advantage that neonate’s airway tone, reflexes and respiratory efforts are maintained if laryngoscopy and intubation fails.

A number of surgical procedure have been described for correction of choanal atresia including endoscopic, transnasal, transseptal and transalatal approach. The anaesthetic approach, includes intravenous induction with muscle relaxant of intermediate duration, endotracheal intubation, maintainence with inhalational agents.

11. Choanal atresia (Fig.6) Choanal atresia is a congenital malformation in which there is no connection between nasal cavity and aerodigestive tract (Prasad et al 2002). It occurs in 1:7000 births with unilateral to bilateral is 2:1. Babies with unilateral atresia have minimal symptoms that can go undiagnosed for months or years. The most common complaint is intractable unilateral anterior nasal discharge.

Splints made from endotracheal tubes are inserted into each nostril and fixed in position with a heavy nylon tie around the nasal septum. They are left in position for six weeks to provide patent nasal airway. The infant should be observed closely in the intensive care unit with appropriate monitoring until breathing dynamics have become normal.

13. Sub glottic stenosis

Babies with bilateral choanal atresia present with acute respiratory distress. Distress can be attenuated if the mouth is kept open with the oral airway strapped in place. 50% of cases are associated with CHARGE syndrome20.

Sub glottic stenosis21 can be congenital or acquired. Incidence of congenital is 5%, the remaining cases are acquired. Acquired subglottic stenosis results from intubation trauma leading to stenosis. Significant contributory factors include prematurity, size and amount of movement of endotracheal tube22, duration of intubation, laryngeal or tracheal injury during intubation and presence of infection during the course of tracheal intubation. The clinical presentation may vary from total asymptomatic to typical picture of severe upper airway obstruction. Patients with signs of stridor who repeatedly fail extubation are likely to have sub glottic stenosis. As with other conditions, diagnosis is made by direct laryngoscopy and bronchoscopy. Tracheostomy is performed if in addition to subglottic stenosis, there is glottic or tracheal involvement. Surgical intervention is ultimately required to correct the stenosis.

Fig 6 Case of choanal artresia showing cut end of the endotracheal tubes into the nostrils as stents to keep choana patent

C: H: A: R: G: E:

Colobomatous blindness Heart disease Atresia of the Choana Retarded growth or development including CNS Genital hypoplasia in males Ear deformities including deafness If there is no associated life threatening conditions Baby can be taken up for surgery as early as possible.

14. Malacia of airways Layngo tracheo or bronchomalacia23 exist when the cartilaginous framework of the airway is inadequate to maintain the airway patency. Caused by lack of neural control of laryngeal muscles. Because cartilage of the infant airway is normally soft, all infants may have some degree of dynamic collapse of central airway. The 278

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congenital variety may be isolated or associated with another developmental defect e.g. tracheo oesophageal fistula or vascular ring. It may be localized to a part of trachea or more commonly may involve entire trachea as well as remainder of the conducting airways. In severe cases, cartilage in the involved area may be missing or under developed. The acquired variety has been associated with long term ventilation of premature new borns due to chronic tracheal injury.

Acute infectious epiglotitis is a relatively uncommon but truly life threatening disease of the childhood. Acute bacterial infection primarily involves supraglottic structures25. Classically, child is sitting up, dyspneic with mouth open. Drooling and drooling resists attempt to lie down. Child looks toxic with high fever and tachycardia. The disease progresses very rapidly and may be fatal with severe airway obstruction within 6-12 hours, unless, immediate steps are taken to restore the patient’s upper airway patency. As soon as the condition is diagnosed child should never be left unattended. Management includes intravenous antibiotics.

Babies with tracheomalacia present with wheeze, a prolonged expiratory phase and croupy cough, all of which increase with agitation and upper respiratory tract infections24. Diagnosis is confirmed by bronchoscopy. Barium swallow may be indicated to rule out co-existing conditions. No treatment is usually indicated for the isolated condition which generally improves over time. Coexisting lesions such as TOF and vascular signs need primary repair.

Endotracheal intubation with a smaller tube is preferred Extubation should be done after 24-48 hours once direct inspection shows decrease in the size of epiglotis.

15. Ludwig’s angina (Fig.7)

17. Foreign bodies in the air passages

It is rapidly progressive cellulitis of the submandibular space that can cause airway obstruction and death. Visualization of glottic opening is impossible because of trismus, oedema and distorted anatomy. To secure the airway fibreoptic intubation may be done n awake and unparalysed state as total upper airway obstruction is a fatal complication. At times tracheostomy through cellulitis although not ideal may be done as a life saving procedure.

These children present26 enormous challenge to the anaesthetist. The problems are of small size of the airways and competition for an airway control and compromised ventilation due to instrument, spasm, bleeding, laryngomalacia and loosened foreign body. There is always possibility of bronchospasm, laryngospasm, cardiac dysrrhythmias due to instrumentation. Care must be taken not to convert partial obstruction into total obstruction27.

16.

18. Postoperative after oral surgery

Epiglotitis

Compromise of airway is the greatest risk in the immediate postoperative period. After palate repair, airway is prone to be compromised. The oedema of the palatal tissue due to surgery, malpositioning of mouth gag, venous engorgement of uvula and tongue interfere with swallowing, thus bloody sputum can be aspirated. Even in vigorous, awake child, extubation28 may result in airway obstruction after palate surgery. This can be relieved by endotracheal intubation or establishment of nasal airway. It is again important to remember that

Fig 7 Ludwig’s angina 279

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adequate ventilation through an endotracheal tube does not ensure the muscle strength to maintain it. Other factors responsible for making the airway compromise in the postoperative period are: • • • • • •

i.

The cause of the difficult airway may still be present e.g. craniofacial anomaly.

ii.

Surgery may have worsened the situation e.g. wiring of the jaws.

iii. Repeated attempts at intubation or use of a too large ETT could have led to trauma and laryngeal oedema. This markedly increases the airway resistance. So one should not extubate if there is any doubt regarding the ability to secure the airway if needed.

Repeated attempts at intubation Change in the body position after intubation Intubation more than 72 hours Surgery on neck Coughing and change in position of head with ETT in place Time of onset of symptoms varies from immediately after extubation to a maximum of four hours till baby settles down i.e. within 24 hours. Thus babies who are at high risk for developing post operative stridor should be closely monitored for at least 3-4 hours postoperatively. Management involves minimal handling of baby and supplemental humidification. Nebulized adrenalin is dramatically effective, but in some babies benefit is transient and symptoms recur within 2 hours. Reintubation with a smaller ETT and nasal CPAP have a role in cases of persistent obstruction.

To conclude, unique anatomical feature of neonatal upper airway themselves make laryngoscopy and intubation difficult. The presence of abnormalities further adds to the difficulty. Awake intubation remains the most appropriate technique in these neonates with anticipated difficult tracheal intubation where rapid control of airway is essential. In all cases of compromised and difficult airway13, it is mandatory to preserve the spontaneous respiration while securing the airway. Fiberoptic bronchoscopic intubation is the ideal choice but problem in our country is of limited availability and needs expertised hands while handling these neonates.

19. Trauma Trauma21 is the major cause of morbidity and mortality in children between 1-14 years of age. If the baby is crying means airways is clear. A quite baby is a baby at risk. One should look for signs of suprasternal in drawing, paradoxical chest movements, snoring, gurgling, stridor, agitation, cyanosis.

LMA is very good alternative in difficult to ventilate babies. At times blind nasal intubation is also successful. Successful management of neonatal and paediatric difficult airway is a multifaceted challenge to the anaesthetist to be approached with caution, requisite preparation and confidence to face unanticipated problems.

95% of polytrauma victim may have associated cervical spine injury. Indications for advanced airway management include persisting airway obstruction. Penetrating neck injury, head and facial injury, chest trauma, apnea and hypoxia.

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