Bronchoscopy in Cats

Bronchoscopy involves advancing an endoscope down into the larynx, windpipe, mainstem bronchus and its divisions, in order to visualize the lumen and lining of these structures. This helps the clinician assess a number of conditions which affecting the respiratory system, and also collect samples to aid diagnosis. 

Bronchoscopy is performed in first opinion practice where suitable equipment is available, and also in referral practice. The patient is fully assessed prior to bronchoscopy and has undergone a detailed physical examination, blood work, and chest radiographs. Bronchoscopy is performed as a final step to confirm a diagnosis and harvest samples for analysis. 

The cat is given a full general anesthetic, which is maintained using injectable agents. The patient is preoxygenated via an endotracheal tube, to stabilize them. The endotracheal tube is then removed and the endoscope passed into the windpipe. Oxygen is either administered via a side channel on the endoscope or else the scope needs removing regularly to oxygenate the patient. 

The scope is advanced slowly down the windpipe and into the mainstem bronchus. The clinician views the images via an eyepiece, searching for areas of pathology. The scope is advanced to the point where the bronchus divides into the right and left lungs. Depending on the size of the bronchoscope, these smaller branches are then explored. 

Biopsy graspers may be used to harvest tissue samples. Alternatively, small volumes of saline are flushed into the lungs, the chest percussed, and then the saline aspirated. The sample is then spread on microscope slides for analysis. Once the examination is complete the endoscope is withdrawn, the patient oxygenated, and then woken from the anesthetic. 

Bronchoscopy is an extremely useful way of gathering information about the lining of the airway and harvesting samples for analysis. Indeed, this is the main way of gathering material from the air spaces in the lungs for culture. 

Alternative methods of imaging include MRI scan, which can provide information about tumors or airway thickening. However, in many ways an MRI is not so useful as directly visualizing the lumen of the airways via bronchoscopy.

Bronchoscopy is not without risk, because it can compromise the amount of oxygen reaching the lungs. However, once the endoscope is removed at the end of the procedure, the patient suffers little in the way of side effects other than that of waking from the anesthetic.

Flow-by oxygen may be provided for a short time after recovery, in order to top up the blood oxygen levels. The patient is observed closely for any signs of airway swelling, secondary to the endoscope being passed. 

Prices vary but expect to pay a minimum of $600 for anesthetic, bronchoscopy, and collection of samples. 

Bronchoscopy is usually the last step in a diagnostic pathway, and performed for a specific reason (i.e. to collect samples). The risks involved are those linked to obscuring the windpipe with an endoscope, however this is taken into account with the choice of anesthetic and techniques for oxygenating the patient. 

Once awake from an endoscopy there should be no lingering after effects. Any saline solution lavaged into the lungs to obtain samples, is rapidly absorbed by the lungs with no ill effect. 

In the long term, the samples obtained can be crucial in determining the correct course of treatment for the patient. 

Endoscopy is most commonly undertaken to diagnose conditions such as feline asthma or pneumonia. It is sensible to avoid smoking in the home as this is linked to airway irritation and sensitivity. 

Trigger factors for feline asthma can include aerosol products, fragrances, and dust mites. Minimizing the use of such products in the home and vacuuming with a HEPA filter can help to reduce the risk of asthma in cats.