Inhaled foreign body
Adults and children can present following the inhalation of a foreign body, but, in young children, this is the commonest indication for a bronchoscopy and one of the leading causes of death. Adults can usually recall the event and the diagnosis is more confident, whereas, in children, this is more difficult, often relying on history, symptoms, and suspicion.
Typically, between the ages of 1 and 4 years old, children are crawling and starting to walk and often put objects in their mouth, nose, and ears. Distress or exercise may result in an uncoordinated inhalation of a foreign body in the mouth, bypassing the usual epiglottic, vocal cord, and laryngeal apparatus protective mechanisms.
What happens next depends on the size and nature of the material inhaled and where it stops. If the foreign body is large and causes complete obstruction of the glottis or trachea, unless immediate action is taken, the child will die from asphyxia at home. Partial airway obstruction presents with various degrees of compromise and urgency, depending on the size of the foreign body, its material, and where the object has stopped. It is this group of children that requires very careful assessment, investigation, and optimal communication and cooperation between the surgeon taking out the foreign body from the airway and the anaesthetist managing this shared airway.
1 Recognize the signs and symptoms of aspirated foreign bodies
2 Instigate appropriate planning for surgical intervention for the removal of a foreign body in the airway
3 Be aware of the difficulties of delivering anaesthesia for rigid bronchoscopy and the hazards of a shared airway.
1C01; 2A01; 2D02
A healthy boy, aged 6 years old, has seen the GP for the second time in the last week. He had been diagnosed with a chest infection 5 days earlier and been started on oral antibiotics. Over the last 5 days, he had developed a wheeze, continued to cough intermittently, and remained pyrexial. The boy has mentioned to the parents that the coughing had started 10 days ago after he had been eating some peanuts.
A healthy girl, aged 3 years and 10 months, has had a persistent cough for the last 24 hours and has presented to the casualty department. A wheeze is present, particularly over the right side of the chest. The parents mention that she started intermittently coughing after a children’s party the previous day and that this has got worse overnight. She is apyrexial; her RR is 26 breaths/min; oxygen saturations are 97% on air, and she looks otherwise well.
A 2-year-old boy presents to the casualty department with a 1 hour history of severe coughing. The coughing had started following a choking episode during a meal which the child had been unable to finish. The parents had initially thought the coughing would settle, but, over the last hour, it had got worse. In between periods of coughing, the child was crying and obviously distressed. He was short of breath, with a RR of 38 breaths/min and oxygen saturation of 93% on air, and was beginning to develop intercostal and sternal recession. There was no stridor, cyanosis, or aphonia, and he was apyrexial.
These three cases highlight the variation in presentation following the inhalation of a foreign body. Foreign bodies within the larynx and trachea can present with acute dyspnoea, stridor, coughing, cyanosis, and aphonia, suggesting an obstruction at a laryngeal level. At the other end of the spectrum of presentations, the child may look well, with no symptoms or signs other than a cough.
In an emergency with a foreign body in the larynx or trachea, the Heimlich manoeuvre or management according to the basic life support ‘choking child’ algorithms with abdominal thrusts and back blows will be necessary.
Most children presenting to hospital have partial airway obstruction as a result of a foreign body in the bronchus, and they present with a sudden onset of choking followed by coughing, wheezing, hoarseness, and shortness of breath. There may be clinically detectable reduced air entry and wheezing on the side of the obstruction.
Case 1 describes a typical history from a child with a late presentation. There may have been some coughing at the time of inhalation, but this may have settled and the child and parents been unaware of its significance. The child may present much later if the obstruction does not pose a functional problem with mucosal irritation, oedema, and pneumonitis distal to the obstruction. Subsequently, the child may have been treated for a chest infection or asthma and finally present with intractable secondary LRTIs
Case 2 describes a child who may have inhaled a foreign body, with the diagnosis requiring an awareness and a degree of suspicion. If left alone, the child may re-present with airway compromise due to obstruction and infection
Case 3 describes a child who has presented with an acute partial airway obstruction, is unwell, and will require urgent management to remove the foreign body.
The history, symptoms, and signs will help differentiate respiratory tract infections, including croup, and pneumothorax and asthma.
More than 90% of foreign bodies are organic material, and this is usually food, with nuts being particularly common. Most are found in one of the bronchi, with the majority inhaled into the right main bronchus because of its anatomical position.
Four types of obstruction have been described:
◆ Check valve: the foreign body in the lower airway/bronchus allows air to be inhaled past it but does not allow exhalation, resulting in emphysema
◆ Ball valve: air can be exhaled, but not inhaled, past the foreign body, resulting in collapse of the bronchopulmonary segment
◆ Bypass valve: the foreign body partially obstructs both inspiration and expiration
◆ Stop valve: there is total obstruction, causing airway collapse and consolidation.
The principal investigation will be a CXR. In cases 1, 2, and 3, a CXR with AP and lateral views should be undertaken, but, in most cases, the foreign body will not be seen because most foreign bodies will be organic material and therefore radiolucent. The CXRs are useful, because they provide secondary signs of partial or complete obstruction such as lobar collapse, consolidation, and atelectasis with stop valve obstruction, and emphysematous gas trapping changes with a check valve obstruction. Significant lobar collapse and gas trapping may cause a mediastinal shift. These secondary findings may not have developed or be visible within the first 24 hours, and most CXR investigations within the first 24 hours are negative. Fluoroscopy or CXRs in inhalation and exhalation may improve the sensitivity of the investigation.
Case 1: evidence of an inhaled foreign body is seen, with secondary signs of collapse and consolidation
Case 2: gives a reasonable history for inhalation, and confirmation with inspiratory and expiratory views may be useful. The child is reasonably stable, and the additional confirmation is worthwhile
Case 3: the positive history, symptoms, and signs are sufficient to justify a general anaesthetic and endoscopic procedure. The CXR showed no collapse, consolidation, or pneumothorax.
In all three cases, a decision is made to proceed with tracheobronchoscopy under general anaesthesia.
This will depend on the presentation and severity of respiratory distress. A child with a convincing history, severe respiratory distress, cyanosis, and obvious airway obstruction should be given 100% oxygen and transferred to the operating room in preparation for tracheobronchoscopy. Foreign bodies in the larynx or trachea will cause more distress and are associated with a higher mortality than those that are usually smaller and pass more distally into the bronchi.
Case 3 is the most urgent with significant respiratory distress and requires urgent intervention.
Ideally, all patients should be fasted for a suitable period. In reality, when a child has severe respiratory distress and requires urgent intervention to remove the foreign body, this becomes more important than strict fasting regimes. In cases 1 and 2, an optimal preparation with a suitable fasting period should be allowed. In case 3, urgent intervention with removal of the foreign body is required, and there should not be a delay for a suitable fasting period.
Once there is a suspicion of an inhaled foreign body, experienced staff should be involved. When a child has severe respiratory distress, senior anaesthetic and surgical staff should be directly involved in the operative management. Senior anaesthetic and surgical staff should be directly involved with all three cases in the operating room.
◆ Sedatives: the administration of any sedative premedication to a child with severe respiratory distress can lead to an unpredictable response with oversedation, worsening of airway obstruction, or total airway obstruction. Most anaesthetists do not give sedative premedication because of these concerns and rely on the presence of the parents to keep the children calm. Premedication was not given to cases 1, 2, or 3, because of the risk of total airway obstruction
◆ Anticholinergics: in the past, these were routinely prescribed, particularly with the use of halothane, to reduce the associated vagal-mediated bradycardia, reflex bronchoconstriction, and secretions. With the more widespread use of sevoflurane, anticholinergics are not always used. Atropine 20 micrograms/kg or glycopyrrolate 10 micrograms/kg help reduce secretions and the reflex bradycardia associated with airway instrumentation
◆ Steroids: although its efficacy is uncertain, dexamethasone is often administered, in an attempt to reduce post-operative swelling and laryngeal oedema following surgical instrumentation and removal of a foreign body. Dexamethasone 0.1 mg/kg was administered to cases 1, 2, and 3
◆ Local anaesthetic: a topical local anaesthetic (lidocaine up to 4 mg/kg) is administered by spray to the vocal cords and trachea. A topical local anaesthetic is important in reducing the reflex responses and cardiovascular stimulation associated with the introduction of metal instruments into the trachea.
IV access should be established before any operative intervention. Topical local anaesthetics, such as Emla® or Ametop®, may be tolerated and, after a suitable time, IV access established. In an urgent situation with severe respiratory distress, there may be inadequate time for a topical local anaesthetic to work, and the child may become too distressed by attempts at IV cannulation. Under these circumstances, it will be more sensible to attempt IV cannulation after inhalational induction.
Familiarity with rigid ventilating bronchoscopes, attachments, and preoperative checks to ensure these are correct and working should be undertaken. Some bronchoscopes allow the attachment of a T-piece to a side arm on the bronchoscope, through which oxygen and volatile agent can pass directly into the distal trachea, acting in a similar manner to an uncuffed tracheal tube. Some bronchoscopes do not allow T-piece attachment. and therefore insufflation or IV anaesthetic techniques are required.
Standard monitoring, including oxygen saturation, capnography, transcutaneous capnometry and neuromuscular monitoring if muscle relaxants are administered.
Traditionally, the general principle around induction and maintenance of anaesthesia is to maintain spontaneous ventilation, usually by an inhalational technique with sevoflurane or halothane, in the hope of reducing the chances of the foreign body being pushed distally into the airway. Dislodging an inhaled foreign body can convert a partial airway obstruction to a more severe, or even complete, obstruction. However, in practice, the maintenance of spontaneous ventilation in a critically obstructed airway can be extremely difficult to sustain, and IPPV may be needed, with some centres routinely using controlled ventilation and muscle paralysis. Recent trials have shown the efficacy of routine paralysis and PPV with better control of ventilation and little impact on dislodgement of the foreign body. Nitrous oxide is not used because of the increased risks associated with gas trapping.
Case 3: induction with sevoflurane in oxygen was started and at a deep plane of anaesthesia, as judged by movements, pupil size, respiratory rate and pattern, and cardiovascular parameters. Laryngoscopy was performed and a topical local anaesthetic administered. Because of its longer duration of action, sevoflurane was changed to isoflurane once a deep plane of anaesthesia had been achieved. Close observation and monitoring was required throughout the procedure to ensure the correct depth of anaesthesia to prevent movement, coughing, and laryngospasm. A rigid bronchoscope was introduced, and isoflurane oxygen insufflated through the T-piece on the bronchoscope. Grasping forceps were introduced through the rigid bronchoscope to remove the foreign body.
Complications occur because of inadequate anaesthesia, inadequate ventilation, and instrumentation of the airway. The consequences of inadequate anaesthesia include coughing, movements, dislodgement of the foreign body, pneumothorax, regurgitation and aspiration, and dysrhythmias. The consequences of inadequate ventilation are hypoxia and hypercarbia, promoting dysrhythmias. Instrumentation may traumatize any part of the airway and cause mucosal oedema, with respiratory distress.
During the removal of the foreign body, it can become fragmented, pushed further into the airway, become lodged, or caught up at the trachea or glottis. If the foreign body is lodged in the trachea, complete airway obstruction may result, and the foreign body needs to be removed immediately or pushed back down into the bronchus. Muscle relaxation at this critical time may be useful by providing a totally relaxed upper airway, from which the foreign body is extracted.
Post-operative care involves a CXR, high dependency environment, humidified oxygen, and observation for airway oedema. Antibiotics in suspected cases of infection and IV steroids to reduce airway oedema may be indicated.
Summary
The presentation of inhaled foreign bodies varies from an emergency in a ‘choking child’ to a partial obstruction and a chronic cough. Most children presenting to hospital have partial airway obstruction as a result of the foreign body in the bronchus and present with a sudden onset of choking, followed by coughing, wheezing, hoarseness, and shortness of breath. The differential diagnosis includes respiratory tract infections, croup, pneumothorax, and asthma. Most foreign bodies are radiolucent and are not seen on a CXR, but secondary signs include lobar collapse, consolidation, atelectasis, and gas trapping. Traditionally, the general principle around the induction and maintenance of anaesthesia is to maintain spontaneous ventilation, usually by an inhalational technique with sevoflurane or halothane, in the hope of reducing the chances of the foreign body being pushed distally into the airway. In practice, the maintenance of spontaneous ventilation in a critically obstructed airway can be extremely difficult to sustain, and IPPV may be needed. Post-operative observation for airway oedema should take place in a high dependency environment.
Gobindram A and Patel A (2008). ENT emergencies. Anaesthesia and Intensive Care Medicine, 9, 277–328.
Patel A (2011). How might a child with an inhaled foreign body present? In: Calder I and Pearce A, eds. Core topics in airway management, 2nd edn, p. 304. Cambridge University Press, Cambridge.