Airway and lug disease diagnostic tests

• Why perform tracheal washing?

  Main indication for patients suspected to have lower airway disease. Indicated in patients that you have concerns about anaesthetising. Is less sensitive than BAL but is easier to perform and can be carried out on the conscious patient.
• Equipment required for tracheal washing

  Long, soft catheter, long anaesthetic, large bore catheter,saline, sample tubes, sterile gloves. Ensure that the long soft catheter fits through the large bore catheter.
• How to do a tracheal wash?

  Clip and prep area around the larynx and ventral neck, proximal to the trachea. Feel for laryngeal cartilages as landmarks.

  Inject local over site between tracheal rings, nick skin with scalpel blade to facilitate passage of catheter.

  Pass large bore catheter between rings into tracheal lumen, remove stylet. If the patient is not cooperative then can sedate (important to retain the cough reflex though).

  Pass long catheter through the large bore catheter down the trachea, inject saline and immediately aspirate to collect material from large airways.
• What are the indications for Bronchoscopy?

  Investigations of unexplained clinical signs. To obtain diagnostic samples, evaluate radiographic lung lesions. Assessment of airways. Treatment of airway disease.
• Benefits of bronchoscopy

  Relatively safe procedure. Diagnostic for a number of conditions. Allows collection of samples. Aloows removal of foreign material. Obtain material for bacteriology, mycoplasma, cytology, bronchial brushes, transbronchial biopsy/ brushing.
• What are the contraindications of bronchoscopy?

  Care with hyper-sensitive airways e.g. cats with allergic bronchial disease, dogs with wheezing suggesting airway spasm. Unstable cardiac failure/ arrhythmias. Care in those patients with tracheal obstruction. Haemorrhage increased risk with pulmonary hypertension, uraemia, coagulopathies and neoplasia/ gross lesions.
• How to perform bronchoscopy?

  Use systematic approach to examine the structures. Collect samples using saline Lavage (BAL), surface brushing (cytology brush), biopsies (care with technique). Samples submitted for culture (bacterial/ mycoplasma/ fungal), viral isolation, PCR for infectious organisms e.g. mycoplasma, cytology.
• Technique for BAL

  Pre-oxygenate. Lodge endoscope in small airway. Instill sterile saline via catheter. Immediate suction after instillation of fluid. If to much suction then can cause an airway collapse and damage. Repeat blouses in same position - first bolus has largest amount of material from large airways.
• Non-bronchoscopic BAL

  Dog urinary catheter or feeding tube (5-6F). Ensure end hole only. Sterile ET tubes, Y connector. Dog in dorsal recumbency. Pre-oxygenate. Plce tube as far as will go until feel resitance. 20-25ml saline and 5ml of air in dogs. 20ml per bolus in 4kg cat - 2-3 sites.
• How to manage patients post-BAL?

  100% oxygen for 5-10 minutes. Gentle positive pressure ventilation (may aid with opening of atelctatic alveoli). If previous stable patient does not respond to oxygen consider; obstruction of ET tube, bronchospasm - bronchodilator, pneumothorax. Normal to auscultate crackles for up to 24 hour post BAL.