When placing airway exchange catheters, be very careful that they do not extend beyond the carina. (Image source: Thinkstock)

When placing airway exchange catheters, be very careful that they do not extend beyond the carina. (Image source: Thinkstock)

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Airway exchange catheters are semi-rigid. As such, they have the potential to damage the respiratory tract if mishandled when used for endotracheal tube exchange. Dr. Robert Axe, Department of Anaesthesia, Royql United hospital, Bath, England, and colleagues used pig trachea and lung specimens less than 48 h postmortem. These tracheas were intubated using 83 cm standard and 100 cm soft-tipped Cook Airway Exchange Catheters, each 3 mm in diameter. They positioned the catheters either above or below the carina at the first point of resistance to advancement, and looked for evidence of lung damage or barotrauma following the administration of oxygen. The results of their analysis are published in this month’s issue of Anesthesia & Analgesia and described in the article titled  “Macroscopic Barotrauma Caused by Stiff and Soft-Tipped Airway Exchange Catheters: An In Vitro Case Series.”

With low flow oxygen there was no lung inflation or barotrauma with either airway exchange catheter when it was placed above the carina. High flow oxygen resulted in lung inflation but not barotrauma with both catheters, provided they were placed above the carina. When either catheter was placed below the carina, lung inflation and barotrauma were seen even at low flow, 2 liters/minute of oxygen.

This was an excellent paper. The authors presented excellent figures to explain their results. The paper addresses an important point of patient safety: be very careful when placing airway exchange catheters. The tip of the airway exchange catheter should not be advanced beyond the carina. Manufacturers should also be encouraged to mark the catheters to indicate maximum insertion depth.