Diseases of the larynx

Emergencies

Stridor

Stridor means noisy breathing. It may be inspiratory or expiratory or occurring in both phases of respiration. Inspiratory stridor is usually due to an obstruction at or above the vocal folds and most commonly is a result of an inhaled foreign body or acute infection such as epiglottitis. Expiratory stridor is usually from the lower respiratory tract and gives rise to a prolonged expiratory wheeze. It is most commonly associated with acute asthma or acute infective tracheobronchitis. Biphasic stridor is usually due to obstruction or disease of the tracheobronchial airway and distal lungs.

Stridor in children (Table 43.7)

Infants and children presenting with stridor need assessment with a full history and careful examination if appropriate. If on presentation a child is cyanosed and severely unwell the airway must be secured as soon as possible but it is often possible to obtain a brief history from the parents, with important pointers. A nurse or colleague may be derailed to do this whilst the resuscitation is taking place.

History. In infants in the first year of life it is important to establish whether the stridor is associated with particular activities such as swallowing, crying or movement. These may suggest congenital laryngomalacia or subglottic stenosis. If the stridor is exacerbated by feeding, particularly in the first 4 weeks of life, this suggests a vascular ring or tracheo­oesophageal fistula. If the cry is weak or abnormal this -suggests a vocal fold palsy. If the problem only occurs in association with an upper respiratory tract infection and, in particular, is biphasic this would suggest congenital subglottic stenosis. In a young child inspiratory stridor and drooling suggest acute epiglottitis, whereas biphasic stridor without drooling suggests laryngotracheobronchitis or croup.

Examination.

Observe the child carefully at rest; do not attempt to move or handle the child, particularly if the stridulous child is being held by its mother or other family member. Once a baby starts to cry it may be impossible to study its resting respiratory pattern for some time. Ask the mother, nor a nurse or a colleague, to move a baby or young child into different positions such as face down and supine, and watch for changes in its respiratory pattern and level of distress. Observe any drooling and with neonates and infants always try to watch the child being fed, listening to the trachea and chest with a stethoscope if possible. Always examine the whole child, looking for any evidence of congenital abnormalities before attempting any examination of the throat.

If a child is stridulous and drooling and sitting upright in its mother’s arms or chair do not attempt to lie it down and do not attempt to look inside the mouth. These are potentially life-threatening circumstances as the child may aspirate a large quantity of thick saliva contained within its oral cavity. The child does nor wish to attempt swallowing in the case of a retropharyngeal abscess, parapha­ryngeal abscess or acute epiglottitis as these conditions are so painful. It is particularly important in acute epiglottitis as the aspiration of thick saliva may be associated with further laryngeal spasm and a respiratory arrest. Restlessness, increasing tachycardia and cyanosis are important signs of hypoxia. If the child is not distressed and drooling, and nor markedly stridulous it may be co-operative enough for it to be possible to look inside the mouth and check the palate, tongue and oropharynx. In stridulous children, particularly neonates and infants, a trans-cutaneous oximeter is invaluable if available. It may be placed on the child before any examination and during any subsequent manage­ment. A resuscitation trolley with the necessary equipment for emer­gency intubation or tracheostomy should be close at hand, if at all possible, before commencing examination and investigation of these children.

  Investigation. In addition to the oximeter, plain lateral X-rays of the neck and a chest X-ray can be obtained but only if the child’s condition permits. If the child is severely stridulous they should not be sent to an X-ray department without access to medical staff or resuscitation equipment. The X-rays may confirm the presence of a foreign body or show soft-tissue shadowing consistent with a retropharyngeal or parapharyngeal abscess, acute epiglottitis or chest disease.

Examination under anaesthesia.

Examination under anaesthesia is essential in all children whose diagnosis remains in doubt. Cytotoxic drugs have nor been found to have significant value as an adjunct to surgery or radiotherapy in the treat­ment of patients with hypopharyngeal squamous carcinoma. It is to be hoped in the future that they will produce better results so that the major surgery and its associated debility can be avoided. Before deciding to give chemotherapy in any form of squamous carcinoma of the head and neck one has to balance the prognosis of the disease against the expected relief and possible toxic side effects. The most commonly used agents are cisplatin, 5-fluorouracil (5FU) and methotrexate. These drugs are best administered by doctors expert in their use and as part of controlled trials until we can evaluate the most suitable method of administration and the best combination of agents. This requires a high level of skill and close co-operation between surgeon and anaesthetist, and appropriate rigid laryngoscopes, bronchoscopes, endoscopic Hopkin’s rods and an operating microscope should be made available.

Equipment should be available at all times to undertake an urgent tracheostomy to establish or maintain an airway.

Acute epiglottitis (Table 43.7)

This illness may occur in adults, although fortunately the stridor rarely progresses as rapidly as in children. In children it is of rapid onset and tends to occur in children of 2 years of age or over. Stridor is usually associated with drooling of saliva. The condition is caused by Haemophilus influenzae infection which initially causes a severe pharyngitis at the junction of the oropharynx and hypopharynx before pro­gressing to produce inflammation and oedema of the laryn­geal inlet. As it progresses it actually involves the whole of the supraglottic larynx, with severe oedema of the ariepiglottie folds and epiglottis being the most notable component; hence the commonly used term ‘acute epiglottitis’. Exami­nation and investigation are outlined above, but these children frequently require intensive management with emergency intubation or tracheostomy followed by oxygenation, humidification, continuous oximetry and antibiotics such as ampicillin or chloramphenicol to combat the haemophilus infection. This may be associated with septicaemia and blood cultures should be obtained. Children with acute epiglottitis may develop airway obstruction rapidly. Insertion of a spatula into the mouth may precipitate a respiratory arrest and is best avoided. Infants and children have small airways and high oxygen demand. It is extremely important to pre-empt

any respiratory arrest.

Laryngotracheobronchitis (croup)

This is usually of slower onset in contrast to acute epiglottitis and occurs most commonly in children under 2 years of age. It is usually viral in origin and the cases often occur in clusters. The children have a biphasic stridor and often hoarseness, and a typical barking cough. Airway intervention is required less often but admission to hospital with oxygenation and humidification coupled with antibiotics may be necessary if there are signs of secondary infection.

Foreign bodies

Both children and adults may inhale foreign bodies. Young children will attempt to swallow a wide variety of objects, but coins, beads and parts of toys are particularly common. In adults the aspiration is usually of food, particularly inade­quately chewed bones and meat. This is more common in elderly edentulous adults and occasionally portions of dentures may be inhaled, particularly in association with road traffic accidents.

Clinical features. The history is often paramount and it is important to always believe the patient, particularly a parent who gives a history of foreign body ingestion or inhalation in a child, even though the pain, dysphagia, coughing, etc., may have settled. Adult patients will, on the whole, have a clear recall and the diagnosis is more easy, but this may not always be the case particularly if the patient is suffering from mental illness. Fish bones may lodge in the tonsils or base of tongue with minimal symptoms but in certain areas of the world, notably Asia, small fish bones may impact in the tonsils, oropharynx or hypopharynx and give rise to parapharyngeal and retropharyngeal abscess formation.

Examination. Examination may be prevented by trismus, pain and anxiety, but the presence of a foreign body may be suspected by a salivary pool within the piriform fossa or adjacent oedema and erythema of the pharyngolaryngeal mucosa.

Radiology.

Radiology may be helpful but is not critical. Fish hones are often not visible on plain X-rays, and a normal plain X-ray does not exclude a foreign body within the pharynx, larynx, oesophagus or lungs. Specialised studies may help in cases of doubt using tomo­graphy of the neck, CT scan or a .gastrograffin swallowing study in the case of a suspected oesophageal foreign body.

  Treatment. In the case of an inhaled foreign body causing severe stridor in a neonate or infant it may be removed either by hooking it from the pharynx with a finger or by inverting the child carefully by its ankles and slapping its back. In a larger child it may be more appropriate to bend them over your knee with their head hanging down and again strike them firmly between the shoulders. In the case of adults an impacted laryngeal foreign body may he coughed out in association with a Heimlich manoeuvre. This involves stand­ing behind the patient, clasping the arms around the lower thorax such that the knuckles of the clasped hands come into contact with the patient’s xiphisternum, and then a brief firm compression of the lower thorax may aid instant expiration of the foreign body.

If none of these immediate emergency measures removes the foreign body and the patient is cyanosed and severely stridulous, an immediate cricothyroidotomy or tracheostomy may be necessary.

If less urgent cases, if the radiography is not useful but a foreign body is strongly suspected, then detailed endoscopy under general anaesthesia may be indicated. It is important to remember that the symptoms of foreign body ingestion are more reliable than the results of specialist radiology investigations. Angioneurotic oedema, radiotherapy, laryngeal trauma associated with road traffic accidents, corrosives, scalds and smoke ingestion may all cause significant pharyngolaryngeal oedema, in addition to the acute infective conditions mentioned elsewhere. Hoarseness is the predominate symptom along with dysphagia prior to the increase in dyspnoea. If laryngoscopic examination is possible marked oedema of the supraglottis and pharynx can be seen. Humidified oxygen, adrenaline nebulisers, systemic antihistamines and steroids may be valuable in these cases. Morphine should not be given to these patients to combat their distress as it may cause respiratory depression and respiratory arrest. If the dyspnoea progresses intubarion or tracheostomy will be necessary. This procedure is to relieve airway obstruction or to protect the airway by fashioning a direct entrance into the trachea through the skin of the neck. Tracheostomy may be done as an emergency when the patient is in extremis and the larynx cannot be intubated but it is not always an easy procedure, particularly in the obese patient, and should not be embarked upon unless absolutely necessary. An easier alternative for the inexperienced doctor is the insertion of a large intravenous cannula or, alternatively, a small tube into the cricothyroid membrane which lies in the midline immediately below the thyroid cartilage. Emergency intubation is a further option when the laryngotracheal airway is not obstructed, and tracheostomy may be performed following initial endotracheal intubarion.

Choice of operation

The degree of urgency in establishing tracheostomy will determine the method used, but preference should always be for the elective procedure. One of the most appropriate pieces of advice in surgery is ‘the time to do a tracheostomy is when you first think it may be necessary’. All of the potential complications of tracheostomy are markedly decreased if a meticulous elective procedure is performed under controlled circumstances by an experienced team

If time allows the following should be undertaken:

  inspection and palpation of the neck to assess the laryngo­tracheal anatomy in the individual patient;

indirect or direct laryngoscopy;

 tomography of the larynx and upper trachea;

assessment of pulmonary function.

Whenever possible the procedure should be adequately explained to the patient beforehand, with particular emphasis on the inability to speak immediately following the operation and possible difficulties with swallowing.

Emergency tracheostomy. If a skilled anaesthetist is unavailable local anaesthesia is employed, but in desperate cases where the patient is unconscious none is required. The only word of warning would be in those patients who have suffered severe head and neck trauma, and may have an unstable cervical spine fracture. Cricothyroidotomy may be more suitable under these circumstances.

If it is possible the patient should he laid supine with padding placed under the shoulders and the extended neck kept as steady as possible in the midline. This aids palpation of the thyroid and cricoid cartilage between the thumb and index finger of the free hand. The movements of the fingers of the free hand are important in this technique. The operation is more difficult in small children and thick-necked adults as the landmarks are difficult to palpate.

A vertical midline incision should be made from the inferior aspect of the thyroid cartilage to the suprasternal notch and continued down between the infrahyoid muscles (Fig. 43.32). There may he heavy bleeding from the wound at this point, particularly if the neck is congested as a result of the patient’s effort to breathe around an acute upper airway obstruction. No steps should be taken to control this haemorrhage, although an assistant and suction apparatus are valuable if available. The operator should feel carefully, and without undue haste, for the cricoid cartilage using the index finger of the free hand whilst retracting the skin edges by pressure applied by the thumb and middle finger. If the situation is one of extreme urgency a further vertical incision straight into the trachea at the level of the second, third and fourth ring should be made immediately without regard to the presence of the thyroid isthmus (Fig. 43.33). The knife blade is rotated through 900 thus opening the trachea. At this point the patient may cough violently as blood enters the airway. The operator should be aware of this possibility and avoid losing the position of the scalpel in the open trachea. Any form of available tube should be inserted into the trachea as soon as possible and blood and secretion sucked our. Once an airway has been established haemostasis is then secured. With the emergency under control the tracheostomy should be refashioned as soon as possible.

Should additional equipment and more time be available once the cricoid cartilage has been identified, blunt finger dissection inferiorly can be used to mobilise the thyroid isthmus which should be divided between haemostats, clear­ing the trachea before making a vertical incision through the second—fourth rings. A tracheal dilator should be inserted through the tracheal incision and the edges of the tracheal wound separated gently. In cases of suspected HIV infection or diphtheria the surgeon should place a swab over the wound so that the violent expiratory efforts which may follow do nor contaminate the operator(s) with infected mucus and blood. When respiratory efforts have become less violent a tracheostomy tube should be inserted into the trachea and the dilator removed. It is important that the surgeon keeps a finger on the tube while the assistant ties the attached rapes round the patient’s neck.

 Elective tracheostomy.

 The advantage of an elective procedure is that there is complete airway control at all times, unhurried dissection and careful placement of an appropriate tube.

 Close co-operation between the surgeon, anaesthetist and scrub nurse is essential, and attention to the details will markedly reduce possible complications and morbidity from the procedure. Following induction of general anaesthesia and endotracheal intubation, the patient is positioned with a combination of head extension and placement of an appro­priate sandbag under the shoulders (Fig. 43.34). There should be no rotation of the head. Children’s heads should nor be over-extended as it is possible to enter the trachea in the fifth or sixth rings under these circumstances. The inexperienced surgeon may find the insertion of a bronchoscope in the trachea of great help when performing tracheostomy in young children. A transverse incision may be used in the elective situation. The thyroid isthmus is divided carefully and oversewn, and tension sutures are placed either side of the tracheal fenestration in children (Figs 43.34-43.38). A Bjork flap may be used in adults. The advantages of the Björk method far outweigh the potential disadvantages, and the method is particularly useful for those surgeons who under­take occasional tracheostomy or where the level of skill and experience of the nursing staff are limited. Performed correctly it is safe and allows reintroduction of a displaced tube with the minimum of difficulty. The inferiorly based flap is begun at its apex with an incision on the superior aspects of the second ring and extended down either side through the second and third rings. The tip of the flap should be stitched to the inferior edge of the transverse skin incision using horizontal mattress sutures through the structure of the second ring. These sutures should be generous enough so that they will nor cur our. The first tracheal ring should not be violated under any circumstances.

Tracheostomy tubes. These are basically made of two materials, silver or plastic (Fig. 43.39). Both materials have been used to make tubes of various sizes with varying curves, angles, cuffs, inner tubes and speaking valves. A cuffed tube is used initially, which may be changed after 3—4 days to a noncuffed plastic or silver tube. The pressure within the tube cuff should be carefully monitored and should be low enough not to occlude circulation in the mucosal capillaries. When in position the tube should be retained by double tapes passed around the patient’s neck with a reef knot on either side. It is important that the patient’s head is flexed when the tapes are tied otherwise they may become slack when the patient is moved from the position of extension, thereby resulting in a possible displacement of the tube if the patient coughs. Alternatively, the flanges of the plastic tube may be stitched directly to the underlying neck skin.

Knowledge of the physiological changes induced by tracheostomy is an essential requirement for the understanding of postoperative management. All forms of tracheostomy and cricothyroidotomy bypass the upper airway and have the following advantages:

the anatomical dead space is reduced by approximately 50 per cent;

the work of breathing is reduced;

alveolar ventilation is increased;

the level of sedation needed for patient comfort is decreased and, unlike endotracheal intubarion, the patient may be able talk and eat with a tube in place. However, there are several disadvantages:

  loss of heat and moisture exchange performed in the upper respiratory tract;

 desiccation of tracheal epithelium, loss of ciliated cells and metaplasia;

  the presence of a foreign body in the trachea stimulates mucus production. Where no cilia are present this mucociliary stream is arrested;

the increased mucus is more viscid, and thick crusts may form and block the tube, particularly in children;

whilst many patients with a tracheostomy can feed satisfactorily, there is some splinting of the larynx which may prevent normal swallowing and lead to aspiration. This aspiration may he ‘silent’, i.e. nor apparent.

  Postoperative treatment is designed to counteract these effects, and frequent suction and humidification are most important (Table 43.9). A trolley must be placed by the bed containing a tracheal dilator, duplicate robes and introducers, retractors and dressings. Oxygen should be at hand and, in the initial period, a nurse must be in constant attendance. Humidification will render the secretions less viscid; a sucker with a catheter attached should be on hand to keep the tracheobronchial tree free from secretions. The catheter must be kept in a sterile holder and introduced with aseptic precautions by all concerned. When mucus is very tenacious and consequently difficult to aspirate, isotonic saline or a mucolytic agent may be administered through the tracheostomy rube by a fine nebuliser. If there is an inner rube it should be removed and washed in sodium bicarbonate solution every 4 hours or more if necessary. A number of complications is associated with tracheostomy but all can be avoided with care and attention to operative and postoperative derail (Table 43.10)

. Other emergency airway procedures. 

Fibre-optic endotra­cheal intubation. In most emergency situations endotracheal intubation is the most direct and satisfactory method of securing the airway. Nasotracheal intubation in expert hands is also a well-established technique and is particularly useful if the patient has trismus, severe mandibular injuries, cervical spine rigidity or an obstructing mass within the oral cavity. Both of these forms of intubation can be aided in difficult patients by passing a modern fibre-optic endoscope through the centre of an endotracheal tube, hence guiding it into the larynx and trachea under direct vision (Fig. 43.40).

Transtracheal ventilation. This technique has been increasingly advocated in the last decade and, although some specialist equipment is required, the actual technique is simple and effective. It will allow ventilation of the patient for periods in excess of 1 hour and will often give ample time to

The cricothyroid membrane is located by palpation of the neck with the index finger, and a 14G or 16G plastic-sheathed intravascular needle and a 10-ml syringe containing a few millilitres of lignocaine are introduced in the midline and directed downwards and backwards into the tracheal lumen (Fig. 43.41). The needle is advanced steadily and negative pressure is placed on the syringe until bubbles of air are clearly seen. The tissues of the neck may be infiltrated with the anaesthetic if desired and the tracheal mucosa likewise partly anaesthetised by the introduction of 1—2 ml after gaining the lumen. The needle is removed and the plastic-sheath cannula remains in the trachea. It is attached by means of a Luer connection to the high-pressure oxygen supply. Ventilation may be undertaken in a controlled man­ner with a jetting device with the chest being observed for appropriate movements. If there is severe obstruction of the laryngopharynx by the foreign body or tumour, the exhaled outflow of gases can be aided by placement of one or two further cannulae as exhalation ports. This procedure gains extremely rapid control of ventilation and requires a minimum of technical expertise.

Ciricothyroidotomy. Cricothyroidotomy has gained increas­ing support in some centres and is advocated when endotracheal intubation is not possible. It has the advantages of speed and ease requiring little equipment and surgical expertise. However, its use for all but the briefest access to the airway remains controversial, and there are conflicting reports with regard to the subsequent incidence of complications, partic­ularly those of subglottic stenosis and long-term voice changes.

The patient’s neck is extended and the area between the prominence of the thyroid cartilage and the cricoid cartilage below is palpated with the index finger of the free hand. In the emergency situation a vertical skin incision is recom­mended with dissection rapidly carried down to the cricothyroid membrane. A 1cm transverse incision is made through the membrane immediately above the cricoid cartilage and the scalpel twisted through a right angle to gain access to the airway (Figs 43.42). If available artery forceps, dilator or tracheal hook will aid improving the aperture and the insertion of an available tube (Fig43.43).

Depending on the degree of emergency it may be necessary for the surgeon to assess the results of the procedure by direct laryngoscopy, and the authors recommend that careful consideration should be given to conversion of the cricothyroidotomy to a tracheostomy. Although there is debate about the frequency of subglottic stenosis following this procedure, there is general agreement that it is much increased if any long-term ventilation is undertaken via even a modest size tracheostomy tube through the cricothyroid membrane.