TRACHEOBRONCHIAL FOREIGN BODY REMOVAL ADVICE IN DOGS AND CATS

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1 Vet Times The website for the veterinary profession TRACHEOBRONCHIAL FOREIGN BODY REMOVAL ADVICE IN DOGS AND CATS Author : MIKE STAFFORD-JOHNSON, MIKE MARTIN Categories : Vets Date : May 13, 2013 MIKE STAFFORD-JOHNSON, MIKE MARTIN discuss airway foreign bodies, anaesthetic considerations and techniques for successful removal of tracheal and bronchial objects Summary Airway foreign bodies in companion animals may be seasonably common, often in late summer or autumn in rural areas. Their removal may be challenging, but the vast majority may be removed endoscopically without the need to resort to surgery. This article provides tips on best removal of foreign bodies safely. Key words airway foreign body, endoscope, snare, grabbing forceps INHALED foreign bodies occur much more commonly in dogs than cats. This article covers those foreign bodies inhaled distal to the larynx. The vast majority of foreign bodies are vegetable in origin (such as grass, grains or sticks). Stones or bones are less commonly encountered. Removal of foreign bodies from the trachea is somewhat different from that distal to the carina. The great majority of foreign bodies may be successfully removed using endoscopy. 1 / 5

2 Clinical signs associated with airway foreign bodies Coughing or gagging, which is acute in onset, is expected. Careful questioning of the owner will often reveal the signs began when the dog was running through grass or corn fields. The majority of foreign bodies are inhaled in this way. Dogs running at high speed through fields containing grass or ripe corn at head height, with their mouths wide open, are most likely to inhale vegetation. The frequency of the cough often remains fairly static throughout the succeeding weeks to months. Typically, there are no signs of illness or dyspnoea, unless rare complications, such as pneumothorax, pulmonary abscess or pyothorax, occur. Haemoptysis is rare. Marked halitosis can follow after several days in dogs inhaling corn heads, as these commonly putrefy. Anaesthetic issues Spontaneous respiration may be preferable to ventilator-assisted respiration to avoid encouraging distal migration of small foreign bodies. These might be inaccessible for endoscopic removal. In rare cases, continued migration while under anaesthesia could induce pneumothorax. Tracheal foreign bodies If possible, removal under fluoroscopic guidance using rigid grabbing forceps is ideal. Tracheal foreign bodies are more likely to be stones, bones or sticks, and these are difficult to grasp using small forceps. Grass and grain heads usually pass further distally into the bronchi. After induction of anaesthesia, a set of rigid forceps may be introduced directly into the unintubated trachea ( Figure 1 ). Incremental doses of intravenous anaesthetic may be administered, if necessary, during the procedure. Gaseous anaesthesia will not be possible at this time. Fluoroscopic guidance enables ready acquisition of the foreign body by the jaws of the forceps. This is then removed with slow passage through the larynx, which, being narrower than the trachea, will offer some resistance to retrieval. In the absence of fluoroscopic facilities, a bronchoscope may be introduced directly into the trachea, which remains unintubated. Either a pair of small grabbing forceps or a snare may be used to grasp the foreign body ( Figure 2 and Figure 3 ). This is more difficult than the aforementioned method, because the larger, rigid forceps with a larger grasping surface allow easier acquisition of the offending foreign body. The bronchoscope and snare/forceps are then slowly retracted through the larynx. 2 / 5

3 Bronchial foreign bodies Bronchial bodies form the majority of the cases encountered. A reasonable knowledge of the bronchial anatomy aids identification of foreign bodies. The widest, most direct bronchi are the most likely to contain the foreign body. Typically, this will mean involvement of the right or, less commonly, left caudal mainstem bronchi. Involvement of the left or right cranial, right middle or right accessory lobar bronchi is rare, which is fortunate as these airways are smaller and less easily approached. These cases will be intubated. The foreign body may be located rapidly. However, before its removal it is advisable to inspect the remaining bronchi to ensure additional foreign bodies are absent. With grass inhalation in particular, multiple foreign bodies can occur. The foreign body is then inspected endoscopically. In many cases, purulent material (or rarely blood) will have accumulated around the vegetation. This interferes greatly with proper visualisation of the foreign body and this discharge should be removed or reduced. Time spent cleansing the site is very worthwhile, enabling much more accurate and rapid grasping of the foreign body. This is particularly important where corn heads are involved. It is all too easy to grasp merely the seed heads, which will invariably break off the main stalk. It is almost always necessary to grasp this central stalk for successful removal ( Figure 4 ). Cleansing is usually achieved by flushing warmed saline around the foreign body and aspiration of the excess saline, if possible. However, the majority of the saline will not be retrieved, as often this is flushed into larger airways, where it dissipates into the various bronchi. This is unlike the situation when performing bronchoalveolar lavage (BAL). However, complications arising from flushing are very rare. BAL is performed typically in more distal sites involving smaller airways, where much more successful aspiration of saline is possible. Direct suction of purulent matter, either by catheter/ syringe combination or via suction machine, seems to be less successful in cleansing the foreign body. Often insufficient retrieval results with this method. The foreign body may be grasped via the following two methods: Endoscopic grabbing forceps By necessity, these forceps have small jaws, as they are required to pass through the biopsy channel of the endoscope. These are good for grasping of grass segments, but less useful for grasping sticks or large grain heads. If removing grain heads, the central stalk must be identified and grasped. Otherwise, successful removal is very difficult, and the grain will fragment. The foreign body is pulled slowly and carefully, proximally in time with slow caudal retraction of the 3 / 5

4 endoscope. When the endotracheal tube is reached, there will be resistance to further passage of the foreign body if this is large, such as a grain head. In such cases, to avoid accidental release of the foreign body at this stage, the endotracheal tube must be removed and the tube, endoscope and forceps are all slowly withdrawn simultaneously. Exercise caution at the larynx, which will provide some additional resistance to withdrawal of larger foreign bodies. After successful removal, reintubation of the trachea is advisable. Tracheobronchoscopy is then repeated. This will allow reinspection for residual particles of foreign body that may have separated from the main stalk. These smaller particles may usually be readily removed. The site of lodgement of the foreign body may then be inspected. Some residual pus or blood may be located here, and typically the site shows some dilation (bronchiectasis). However, this does not appear to lead to long-term complications. The site should be cleansed and inspected to ensure no residual fragments are located either at the site or further distally. Snares Snares are extremely useful for larger foreign bodies, those containing thorns or any wedged firmly in a bronchus. The smaller grabbing forceps are limited in the degree of traction that can be applied before the jaws slide off the foreign body. A snare allows a much firmer hold of the offending object. It is introduced via the biopsy channel in a closed state. It may then be opened cranial to the foreign body and advanced slowly alongside it, with the use of small deft motions to capture the object. The snare is then tightened around the object like a noose. To avoid tearing of airways, vigorous pulling of the snare is not advised. Such pulling could possibly lead to pneumothorax or airway haemorrhage. Two tips may be borne in mind at this time if stiff resistance is encountered: Allow ample time and exercise patience. Mild to moderate sustained traction, across 10 to 15 minutes on occasion, may finally remove the object. Do not expect the foreign body to be removed immediately in every case. When starting to exert traction, have an assistant fully inflate the lungs if a rebreathing bag is present on the anaesthetic circuit. The valve on the bag is temporarily closed. The assistant exerts slowly increasing pressure on the bag to fully inflate the lungs. These should not be overinflated and this should be continually checked by the assistant s observation of the degree of expansion of the chest wall. 4 / 5

5 Powered by TCPDF ( This action increases the diameter of the bronchi maximally and maximises the removal of tight foreign bodies. It is an extremely useful technique in such cases. We have not routinely cultured these cases once removal is complete. Mild airway damage by the foreign body is likely during the procedure. This does not seem to cause longterm problems. Broad-spectrum antibiotics, such as amoxicillin, are often supplied for one week as a precaution against airway infection. 5 / 5