EMS Equipment - Murphy's Endotracheal Tube

For EMS providers, understanding the Murphy Endotracheal Tube and its key feature, the “Murphy Eye,” is essential for ensuring patient safety during airway management. 

The Murphy eye serves as a critical safety mechanism that prevents complete airway obstruction if the main distal opening of the tube becomes blocked. It is also an example of an eponymous medical term.

Recognizing this feature and the overall design of the endotracheal tube can help prevent complications during intubation and ensure the continued delivery of oxygen to patients in emergency situations.

The “Murphy Eye” Explained

The Murphy Eye is the eponymous term for a small hole on the side of most endotracheal tubes (ETTs). It functions as a vent, preventing complete obstruction of the patient’s airway if the primary distal opening of the ETT becomes occluded.

Dr. Francis J. Murphy (1900–1972) was a strong advocate for the continuous supply of oxygen during anesthesia. In 1941, he outlined the nine characteristics of the "ideal" endotracheal tube (ETT). In the same article, he introduced two tubes with innovative features. 

One tube was straight with two side holes, while the other was curved with one side hole. Both lacked cuffs and were made from high-quality red rubber that balanced flexibility with resistance to compression or kinking, even after multiple uses and heat sterilizations.

Although most ETTs today are made from disposable plastic, they still require a similar balance of flexibility and resistance to compression. Most continue to incorporate the crucial safety feature that bears Dr. Murphy's name: the "Murphy eye."

The featured image show the orginal tube, owned by Dr. Murphy himself, and bears his initials. It features an inflatable cuff located above the "eye," which is inflated via a small side tube attached to the ETT. 

Further Reading:

Bledsoe, B. E., Cherry, R. A. & Porter, R. S (2023) Paramedic Care: Principles and Practice (6th Ed) Boston, Massachusetts: Pearson

Brown, C. A. (2022) Walls Manual of Emergency Airway Management (5th Ed). Philadelphia, Pennsylvania: Lippincott, Williams & Wilkins.