Chapter 29: Foreign bodies in the larynx and trachea. J. N. G. Evans

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1 Chapter 29: Foreign bodies in the larynx and trachea J. N. G. Evans Even the most experienced of endoscopists would agree that the prospect of having to deal with a very young child with a history of possible inhalation of a foreign body, fills them with some trepidation - not only because of the demands that the removal of a foreign body makes on their skill as an endoscopist, but also on account of the fact of the unpredictability in the degree of difficulty of the procedure. The degree of difficulty will depend on a number of factors: the age of the patient, the type of foreign body inhaled, the interval between inhalation and removal, the skill of the anaesthetist and the equipment available. A strong case can be made for every 6-month-old child with a suspected peanut in the bronchus, which has been there for 3-4 weeks, being referred to a specialist centre for its removal. Modern techniques of endoscopic removal of bronchial foreign bodies stem from the advances made in the early part of the century by Chevalier Jackson, who reduced the mortality of removal of foreign bodies from over 20% to approximately 2%. He achieved a 98% success rate of bronchoscopic removal of foreign bodies, all the procedures being performed under local anaesthesia. Since then, improvement in the illumination provided by the Hopkins rod lens system and the advent of the ventilating bronchoscope (Hopkins, 1976), coupled with the advances in anaesthesia, have further reduced the mortality and greatly facilitated the task of the endoscopist (Tucker, 1985), and most paediatric endoscopists use these instruments and perform the removal of the foreign body under general anaesthesia (Gans and Berci, 1971). Other techniques such as postural drainage (Burrington and Cotton, 1972; Campbell, Cotton and Lilly, 1982), the Heimlich (1975) manoeuvre and the introduction of fingers into the pharynx in an attempt to remove the foreign body, are to be deprecated, since these manipulations may dislodge the foreign body and cause total respiratory obstruction and hypoxic cardiac arrest. Incidence The maximum incidence of inhalation of foreign bodies occurs between the age of one and three years: 74% of 115 patients (Brown and Clark, 1983) and 77% of 225 patients (Rothman and Boeckman, 1980); 74% in a much larger series (Jackson and Jackson, 1936). Holinger (1962) found that children under 4 years old constituted 55% of their series of foreign bodies, but their cases included adults. The most common cause of accidental death in the home in children under 6 years of age, is the inhalation of a foreign body (National Safety Council of America, 1980). It is estimated that almost 600 children under 15 years old die per year in the USA from asphyxia following the aspiration or ingestion of large foreign bodies. The peak incidence of inhalation of foreign bodies in early childhood is of course related to the fact that children have a habit 1

2 of putting objects into their mouths to determine their texture and taste, and to chew on when teething. It is extremely important, therefore, where possible to keep objects which might be inhaled out of the reach of small children. Table 29.1 shows the types of foreign body removed in Rothman's series (Rothman and Boeckman, 1980). Boys are more likely to inhale foreign bodies than girls by almost 2:1 (Rothman and Boeckman, 1980; Brown and Clark, 1983; O'Neill, Holcomb and Neblett, 1983; Schloss, Pham-Dang and Rosales, 1983). The reasons for this are not clear! Table 29.1 Type of foreign body Type Number Portion of nut 86 Food 32 Carrot 18 Popcorn 8 Fruit (stem/seed) 5 Bone 8 Plastic 27 Metal 19 Tooth 4 Stone 4 Timothy hay 4 Bead 2 Mucus 2 Balloon 1 Crayon 1 Wood 1 Paper 1 Acorn 1 Pine needle 1 A minority of these objects impact the larynx; 4% in Cohen's series (Cohen et al, 1980) were removed from the larynx. Foreign bodies lodge in the larynx if they are too large to pass through or if they are of an irregular shape or have sharp edges which can catch on the laryngeal mucosa. Egg shells and fragments of glass or plastic are not infrequent offenders. History In most cases of inhaled foreign body, there is a definite history of choking followed by paroxysmal coughing which then subsides. In 85% of the patients in Rothman's series (Rothman and Boeckman, 1980), a positive history of aspiration was obtained but in some patients this positive history is only obtained retrospectively, after removal of the foreign body. After the initial paroxysm of coughing the tracheobronchial mucosa becomes tolerant of the foreign body and coughing ceases. This feature is often responsible for delays in 2

3 diagnosis - 18% of cases of foreign body were diagnosed one week and 8% one month after the event (Rothman and Boeckman, 1980). In Cohen's series, 50% of the cases were recognized and treated within 24 hours and, by 10 days, 74% of the cases had been treated, 26% of the cases being diagnosed between 10 days and one month (Cohen et al, 1980) (Table 29.2). In a series of 51 cases of foreign body reported by Ross and McCormick (1980) there was no history of aspiration in 8%. One symptom of the triad - coughing, choking and wheeze - was present in 91% of patients with foreign body aspiration (Black et al, 1984). Table 29.2 Duration of enlodgement Duration Number 2-8 hours hours days days days months months 2 Longer 1 A history of wheeze, often diagnosed and treated as asthma, is the next most common symptom. Sudden onset of a wheeze in a child not previously known to have asthma, should alert one to the possibility of a foreign body being the cause - especially if the wheeze is predominantly unilateral. Unexplained persistent fever, a fever associated with persistent respiratory symptoms which continues in spite of treatment, and persistent or recurrent lobar pneumonia demand a diagnostic bronchoscopy to exclude a foreign body. Most endoscopists have on some occasion found an unsuspected foreign body at routine endoscopy for other reasons. The author has removed the horizontal limb of a Montgomery 'T' tube from the trachea of a child with laryngeal stenosis. There was no history of any previous treatment of his stenosis and the plastic tube found quite by chance at routine endoscopy. Acute respiratory distress is, fortunately, an uncommon but most alarming presentation of an inhaled foreign body. Fourteen or 6% of the patients in Rothman's series (Rothman and Boeckman, 1980) presented with respiratory distress, five of these patients having had a laryngeal foreign body. Pain at the root of the neck or over the larynx also suggests the presence of a laryngeal foreign body. Large oesophageal foreign bodies may compress the trachea and cause symptoms of respiratory obstruction. Sharp and long-standing oesophageal foreign bodies may produce a fistula between the oesophagus and trachea and cause respiratory symptoms (Yee, Schild and Holinger, 1975). Clinical examination A general examination of the child is essential. Respiratory distress or cyanosis demands immediate action; special care should be taken during the induction of anaesthesia 3

4 in these patients since the foreign body may change position and completely obstruct the airway. Inhaled foreign bodies are more common in children with upper respiratory tract infections, caused presumably by mouth breathing and the presence of a cough - inhalation of food particles may easily occur with the sharp intake of breath which follows a cough. If there is a change in the child's cry or if the cry becomes hoarse or stridulous, a laryngeal foreign body should be suspected. Excessive salivation may also occur. In the first few hours after aspiration the signs in the chest are due to changes in air flow through the tracheobronchial tree. These changes may be detected with a stethoscope on auscultation of the chest. An audible click may be heard due to movement of the foreign body up and down the trachea; a fluttering noise may also be detected due to rapid oscillation of the object in the air stream in the trachea or main bronchi. A unilateral expiratory wheeze and reduced air entry may indicate a foreign body in the bronchus. Obstructive emphysema may be detected by mediastinal shifts but is most easily detected radiologically and will be discussed more fully later in the chapter. If the foreign body is not removed within 24 hours, pneumonic sings supervene. The severity of these signs will depend on the reaction of the bronchial mucosa to and the size of the foreign body (Strome, 1977). If the foreign body is of vegetable origin an intense inflammatory reaction of the bronchial mucosa occurs, ultimately with the production of granulation tissue. The mucosal swelling and inflammatory exudate may then obstruct the bronchial lumen, causing atelectasis of the distal lung. A lung abscess may then supervene but this takes several months. An unusual complication of a foreign body in the bronchus, namely a brain abscess, was reported by Spencer et al (1981) - a child inhaled a grass head which entered the bronchus, stem first. This enable the grass head to migrate peripherally, causing pneumonia and a lung abscess, which in turn caused a cerebral abscess. The time interval between inhalation and development of the brain abscess was 3 months. Dry vegetable foreign bodies, for example a bean, cause very rapid obstructive changes due to a combination of mucosal irritation and swelling of the bean itself by hygroscopic action. Atelectasis of the occluded segment of lung occurs with the utmost rapidity in this type of foreign body. The presence of florid granulation tissue around the inhaled foreign body may also cause haemoptysis. It occurred in 6% of cases in a series reported by Ross and McCormick (1980). Haemoptysis itself is a rather uncommon symptom in the paediatric age group. Tom, Weisman and Handler (1980) investigated 40 patients who presented with this symptom and found 15% of the cases were due to a foreign body. If the foreign body is made of ferrous metal or it has a particularly rough surface, some bronchial irritation will occur, but the process of bronchial occlusion will, however, take much longer. 4

5 If the foreign body is inert and has a smooth surface, very little mucosal reaction takes place and pneumonic changes may never supervene. Radiological findings X-ray examination of the patient must be performed and should include all the structures from the nasopharynx to the tuberosities of the ischia, otherwise a foreign body may be overlooked (Jackson and Jackson, 1936). X-rays should be taken with the neck extended with anteroposterior and lateral views. Anteroposterior views in expiration and inspiration should be obtained, although these views are sometimes difficult to obtain in very young children. A lateral chest X-ray completes the examination. Screening may also help but standard X-rays are usually sufficient (Gaafar et al, 1982). Computerized tomographic studies may help to show a foreign body not seen with conventional studies (Berger, Kuhn and Kuhns, 1980). Isotope scans will demonstrate changes in ventilation and perfusion of lung tissues. These more sophisticated radiographic techniques are rarely necessary in obvious cases of inhaled foreign bodies. They should not be ordered if they delay the definitive endoscopic assessment of the patient. Obstructive emphysema Obstructive emphysema is produced by a valvular obstruction to the expiratory air stream due to the presence of a foreign body in the lumen of the air passage. It also occurs in endogenous extrinsic compression of the intrathoracic air passages. The action of the valve is due to the fact that the air passages dilate on inspiration and contract on expiration. Thus, on each respiration, a small volume of air is trapped beyond the obstruction and the lung is literally pumped up with air during each phase of the respiratory cycle. There is mediastinal shift during expiration to the unobstructed side of the chest; in inspiration the mediastinum may be in the midline. In atelectasis of the lung, mediastinal shift occurs towards the obstructed side of the chest, the mediastinum remaining deviated during inspiration and expiration. Tables 29.3 and 29.4 show the relative incidence of radiological findings in the Rothman (Rothman and Boeckman, 1980) and Black (Black et al, 1984) series. Table 29.3 X-ray findings Radiological signs Patient nos Obstructive emphysema 135 Foreign body visualized 31 Atelectasis 27 Pneumonia 18 Normal 17 Mediastinal emphysema 4 Positive plain X-ray evidence suggestive of a foreign body was obtained in 81% of patients in a review of Black et al (1984), who also reported 88% of radiographic screening to be positive. Normal radiographs were noted in approximately 10% of the patients in whom foreign bodies were found at bronchoscopy. The time interval between inhalation and 5

6 abnormal radiological findings was noted by Baraka (1974) and he found negative X-ray evidence of a foreign body within 24 hours of inhalation in his paediatric patients; this figure altered dramatically after 24 hours when abnormal X-rays were noted in 90% of the patients. Table 29.4 Radiographic findings in patients with airway foreign bodies Radiographic signs Patients No % Air trapping Atelectasis Perihilar infiltrates Opaque foreign bodies Lobar collapse 4 2 Other 9 4 Normal radiograph Radiograph nod obtained Site of foreign body The majority of foreign bodies come to rest in the right bronchial tree, since the right main bronchus is wider than the left and the interbronchial septum projects to the left. The effect of the inspiratory air currents also determines the site of final impaction and the anatomical differences between the right and left bronchial septum are of less significance than might be supposed (Moazamn, Talbert and Rodgers, 1983). In Jackson's series (Jackson and Jackson, 1936), 588 foreign bodies were on the right and 322 on the left, a ratio of 1.82:1. In young children, where the difference is less pronounced, there is a more equal distribution of foreign bodies between the right and left bronchial tree. In Svensson's (1985) series of children only, there were 59 foreign bodies in the right bronchial tree and 46 in the left, a ratio of 1.28:1. Management If a foreign body in the respiratory tract is suspected or diagnosed radiologically, endoscopic examination and removal, under general anaesthesia, is the method of choice. In the case of laryngeal or large tracheal foreign bodies this should be performed as an emergency procedure. If the airway is compromised, the endoscopy must be performed immediately with the facilities for performing an emergency tracheostomy. Large tracheal foreign bodies may have to be delivered through a tracheostomy (Swennson et al, 1985). Bowdler and Emery (1985) recorded two cases of unusual foreign bodies in the trachea. In both cases silver tracheostomy tubes became detached from their neck plates - due to failure of the braising material. The tubes had been in use for a number of years, and the inhaled tubes were removed from the tracheostome with some difficulty! If the airway is not compromised the procedure should be performed within hours, allowing a suitable time to elapse for the stomach to be empty. 6

7 Laryngeal foreign bodies are removed by direct laryngoscopy. In the majority of cases this is accomplished without difficulty, often indeed in the anaesthetic room much to the delight of anaesthetic colleagues. Rarely, large foreign bodies may cause total respiratory obstruction during induction of anaesthesia and an emergency tracheostomy will then be necessary. A commonly encountered difficulty in cases of laryngeal foreign body is delay in diagnosis (Moskowitz, Gardiner and Sasaki, 1982). Tracheal and bronchial foreign bodies are best removed using a rigid bronchoscope. In the absence of respiratory distress the operation should be performed as an elective procedure, by the 'surgical team' that are used to working together in their accustomed operating theatre. Under these 'ideal' circumstances, a 99% success rate for removal of foreign bodies should be achieved. There is no place for endoscopy for a foreign body being performed in an infant by inexperienced personnel in unfamiliar surroundings (Bush and Vivori, 1981). In the author's opinion the efficiency and safety of rigid bronchoscopy completely supersedes any form of conservative approach using bronchodilators, thoracic percussion and postural drainage (Burrington and Cotton, 1972). Indeed this technique of inhalation and postural drainage may be the cause of severe respiratory obstruction and even hypoxic cardiac arrest, if the foreign body is moved and impacts in the subglottis (Kosloske, 1980). Preoperative physiotherapy, together with the administration of antibiotics is, however, useful in patients with a peripherally situated, usually organic, foreign body of long standing, in which there is considerable atelectasis of the lung with pneumonia or a lung abscess. Postoperative physiotherapy is also helpful in expanding areas of atelectatic lung. In the rare event of being unable to remove a foreign body endoscopically, in spite of satisfactory operating conditions, it must be removed by thoracotomy and bronchotomy. In practice this generally has to be organized as a separate procedure, since the decision to abandon the bronchoscopic attempt at removal is only made after an already prolonged struggle to remove it bronchoscopically. The author recalls having to abandon a bronchoscopy in a 2-year-old child who had choked on a pebble, after his father in attempting to remove it with his finger, had pushed it through the laryngeal inlet. The pebble was oval in shape and almost exactly fitted the glottis. Once in the trachea sufficient air was able to pass around it to maintain respiration, but the author was unable, however, to exert sufficient traction with a pair of forceps to pull it back through the larynx. It was successfully removed at thoracotomy the following day. Technique of removal In most cases removal of the foreign body is undertaken as an elective procedure - in this instance the surgical anaesthetic and nursing personnel know each other and the 'team' are able to perform their allotted tasks efficiently and peacefully. These factors increase the chances of a successful removal of the foreign body and reduce the operative morbidity. Instruments A complete set of ventilating bronchoscopes with a Hopkins rod lens system, such as manufactured by Karl Storz, is used by many paediatric endoscopists (Table 29.5). These 7

8 instruments, but virtue of their superior illumination and optics, which magnify the image nine times improve the visualization of the foreign body in the infant and young child. The bronchoscopes are equipped with two side channels, one for ventilation and the other for instrumentation and suction. The disadvantage of these instruments is that the side channel will permit the introduction of very small forceps, and the author finds that the removal of soft foreign bodies (for example peanuts) is made easier by using the larger Chevalier Jackson instruments through an open bronchoscope. Table 29.5 Recommended set of Storz bronchoscopes Diameter (mm) Length (cm) For this reason the author also has available a set of Negus bronchoscopes in the following sizes: suckling, infant, child, adolescent and small adult. A swing-arm magnifier is available for use with these instruments and provides a magnification x 4. This enables assessment of the forceps space between the foreign body and the bronchial wall so the best position for insertion of the instrument can be determined. The irregular shape of most foreign bodies will allow the forceps to be inserted in the gap between the foreign body and the bronchial wall, thus reducing the risk of pushing the foreign body distally and jamming it into the bronchus. In older children, the combined bronchoscope and grasping forceps overcome the difficulty of removing soft foreign bodies because the jaws of the grasping forceps are larger and prevent the fragmentation of soft vegetable foreign bodies, which occurs with smaller 'side-arm forceps'. In some centres (Kosloske, 1980), Fogarty balloon catheters designed for arterial embolectomy are used particularly in the removal of peanuts (Stein, 1970). The catheter size 3 or 4 is passed down the side-arm of the Storz bronchoscope. The tip of the catheter is passed beyond the foreign body and the balloon is inflated with saline (Wiesel et al, 1982; Bannerjee, Khanna and Narayanan, 1984). The telescope is withdrawn approximately 1 cm to allow space for the presenting part of the peanut to be accommodated within the lumen of the bronchoscope as traction is exerted on the Fogarty catheter. The catheter, bronchoscope and foreign body are removed together. The Fogarty catheter is also useful for removing foreign bodies with holes, for example beads: the catheter can be threaded through the hole, inflated and the foreign body removed. A Dormia basket used by urologists to remove ureteric calculi may also be used in a similar manner (Dajani, 1971). 8

9 Before commencing endoscopy, the surgeon must be satisfied that all the equipment is in working order. This applies particularly to the jaws of the Jackson forceps - these are made of spring steel which tends to rust and, therefore, may jam in the outer casing of the forceps. Suckers must be checked for patency and also that they are long enough to protrude beyond the end of the bronchoscope. Bronchoscopes and forceps, suitable in size and shape for the case in hand, are selected. Practice passes of the forceps through the chosen bronchoscope are made, the blades of the forceps are inserted into the bronchoscope and then opened, and the emergence of the opened forceps beyond the tip of the bronchoscope is felt rather than seen, because of the lack of stereoscopic vision down the bronchoscope. This manoeuvre is practised, while the patient is being anaesthetized, until the surgeon is confident that he will know when the tip of the forceps is just protruding beyond the end of the bronchoscope. This is the correct position for grasping the foreign body. In cases where a particular difficulty is likely to be encountered, for example open safety pins or other sharp foreign bodies, the use of a dummy tracheobronchial tree and a duplicate foreign body will enable the surgeon to practise the manoeuvre necessary to remove the foreign body safely. Time spent in practice will be amply rewarded by reducing the time spent during the actual endoscopy. The actual technique of bronchoscopy is described in Volume 5. Special care must be taken in young children to keep the bronchoscope in line with the trachea to ensure adequate ventilation of the patient. Ventilation may be difficult when the bronchoscope is passed deeply into the obstructed bronchus; adequate ventilation will be maintained if the holes in the side of the bronchoscope remain unobstructed, and direct towards the normal main bronchus. When the precautions mentioned above are taken, a successful removal of a foreign body can be achieved in the majority of cases. Following removal It is very important after removal of the foreign body, while the child is still anaesthetized, that a second look is taken to ensure that a second foreign body has not been overlooked, and to remove any remaining small fragments particularly in the case of peanuts. Pus and mucus can be aspirated from the distal bronchus - speeding the resolution of atelectasis or pneumonia. It is also important to make sure that all major bronchopulmonary segments including the upper lobe orifices are inspected. If the bronchoscopy is prolonged, or if the bronchoscope was noted to be a tight fit in the subglottic larynx, the use of a systemic corticosteroid, dexamethasone 0.5 mg/kg, is advised to reduce the incidence of laryngeal oedema postoperatively. Prevention The vast majority of cases of inhaled or ingested foreign bodies occur as a result of carelessness either in the preparation or ingestion of food or drinks, or as a result of placing inedible or unsuitable objects in the mouth. The accidental inhalation or ingestion of foreign 9

10 bodies is therefore almost entirely preventable. Infants and children under the age of two should not be allowed to eat peanuts, and their play areas should be cleared of small objects that could be inhaled. Adults should set a good example by never placing pins or tacks in their mouths. The long-term deleterious effects of a foreign body on the lung parenchyma, such as lung abscesses or bronchiectasis, are also preventable provided that the medical attendant of the child always considers the possibility that a foreign body may be present (Clerf, 1952), even in a case where a good history of inhalation has not been obtained, in a patient who develops a wheeze where asthma has not been previously diagnosed, or when pneumonic signs persist for a longer period than one would expect. In such cases a bronchoscopy should always be performed. 10