Murphy Eye Endotracheal Tubes: Design, Function, and Practice

This article examines the design, purpose, and clinical applications of Murphy eye endotracheal tubes. It explains how the unique side hole improves patient safety, details the components and materials used, and outlines best practices for sizing, insertion, and usage in various medical scenarios.

What you’ll learn:

• What a Murphy eye endotracheal tube is and how it works
• The history and purpose behind Dr. Francis J. Murphy’s design
• Key design features, including the beveled tip, Murphy eye, and radio-opaque lines
• Advantages over standard endotracheal tubes in preventing airway obstruction
• Common clinical uses such as anesthesia, postoperative care, and emergency intubation
• Guidelines for selecting the right tube size for adults and children
• Step-by-step insertion techniques for safe and effective intubation
• Training recommendations for medical and nursing students using manikins and simulators

Endotracheal intubation is a common medical procedure performed on patients to keep their airways open for the administration of medicine, anesthesia, or oxygen. The nurse or medical professional must insert a special tube through the patient’s nose or mouth and into the windpipe (trachea) to keep the airway open. Many patients facing emergency conditions or those undergoing surgery will often have this procedure performed on them.

What is the Murphy Eye Endotracheal Tube?

A Murphy eye endotracheal tube is a unique type of endotracheal tube that features a “Murphy eye,” a hole on the side of the tube that serves as a port for a ventilator. The purpose of the Murphy eye is to prevent the patient’s airway from becoming obstructed by mucus or some other mass. Most medical practitioners use Murphy eye endotracheal tubes because they are safer and more effective for patients than the traditional ones.

Dr. Francis J. Murphy is the doctor credited with inventing the Murphy eye endotracheal tube in the early 20th century. He was unhappy with the standard endotracheal tube because it featured a single beveled tip that would easily get blocked by secretions and mucus. His Murphy eye endotracheal tube addressed this problem by creating a hole for gas flow to escape in the event of obstructions in the tube.

We will dive deeper into the design, function, and clinical practice of the Murphy eye endotracheal tube as you continue reading this article.

The Design of the Murphy Eye Endotracheal Tube

The typical Murphy eye endotracheal tube is a thin, transparent, flexible tube made of polyvinyl chloride (PVC). You may find reusable tubes made of silicone, but the PVC ones are preferred since some patients are allergic to silicone. Even though the PVC tubes are disposable, they are safer for patients.

Each Murphy eye endotracheal tube features a beveled distal tip and thermosensitive tubes with strong, thick walls and kink resistance. The unique feature of this endotracheal tube design is the Murphy eye, a small round hole on the side of the tube near the beveled tip and the cuff inflator. The Murphy eye serves as an alternative ventilation pathway to ensure consistent airflow if the distal tip becomes clogged with obstructive secretions.

The connector is on the other side of the tube. A pilot balloon connects to the cuff to monitor the inflation status. All along the side of the tube, you will see radio-opaque lines to make it easier to confirm the proper placement of the tube as you observe it on X-rays.

The Murphy eye endotracheal tube is a disposable device, meaning each tube must be discarded after it is used once. You can buy a box of disposable Murphy eye endotracheal tubes from credible medical suppliers like Pristine Medical.

The Function of the Murphy Eye Endotracheal Tube

The top core function of the Murphy eye endotracheal tube is to prevent the total obstruction or blockage of the airways during intubation. Any patient with respiratory issues, such as pediatric patients with smaller airways, can benefit the most from Murphy eye endotracheal tubes.

Of course, it is advisable to use Murphy eye endotracheal tubes over standard ones because they are safer while remaining equally effective. The Murphy eye and beveled tip make it easier to perform common examinations, such as laryngoscopy, where a medical practitioner uses a laryngoscope to examine the patient’s voice box (larynx).

Murphy eye endotracheal tubes are frequently used when a doctor administers general anesthesia because they help control ventilation more effectively. Similar to the laryngoscopy procedure, there is a significant risk of the beveled tip becoming blocked with mucus during anesthesia. The Murphy eye allows airflow to continue when this kind of obstruction exists.

Clinical Practice

Here are some of the most common medical situations where a Murphy eye endotracheal tube would be used:

• Postoperative surgical recovery

• Emergency intubation

• General anesthesia

• Mechanical ventilation

• Certain diagnostic procedures (e.g., bronchoscopy, laryngoscopy)

• Head surgery

• Neck surgery

Medical and nursing students should understand how to use the Murphy eye endotracheal tube in these medical procedures and scenarios. Let’s review all the carious clinical practice considerations that your students will need to make when applying the Murphy eye endotracheal tube to a patient:

Selecting the Proper Size

Not all Murphy eye endotracheal tubes are the same size. You must select the appropriate tube size based on the patient's age, height, and weight. It is best to train your students on a variety of different manikins and tube sizes to ensure they know which tube is best to use with which manikin.

Here are some examples:

• Adults up to 160 centimeters in height – 7.0 mm tube size

• Adults between 160 and 179 centimeters in height – 7.5 mm tube size

• Adults over 180 centimeters in height – 8.0 mm tube size

• Children up to 4 years old – 3.0 to 4.0 mm tube size

• Children between 4 and 8 years old – 4.0 to 6.0 mm tube size

The basic formula for choosing tube size is as follows:

Age in years / 4 + 4 = ETT Size (mm)

Choosing the correct tube size reduces airway resistance and the risk of trauma.

Insertion Technique

Here are the general steps of intubation with a Murphy eye endotracheal tube:

1. Provide oxygen to your patient before you begin.
2. Lubricate the beveled distal tip and cuff of the Murphy eye endotracheal tube.
3. Inflate the cuff with air to test it out by using a syringe. If it inflates properly, deflate the cuff.
4. Position the patient in a sniffing position, where their oral axis, laryngeal axis, and pharyngeal axis are all aligned.
5. Use the laryngoscope device to raise the tongue and epiglottis to get a view of the vocal cords.
6. Use a stylet to guide the Murphy eye endotracheal tube, with the Murphy eye feature facing the right. Move the Murphy eye area toward the back of the airway. The cuff should be about 2 to 3 centimeters past the vocal cords.
7. Inflate the cuff at a low volume. Don’t use too much pressure.
8. Confirm that you have properly placed the Murphy eye endotracheal tube by using auscultation to listen for breathing sounds and capnography to measure carbon dioxide levels as the patient exhales air.

Get Your Murphy Eye Endotracheal Tubes Today

Check out Pristine Medical for the best Murphy eye endotracheal tubes and other realistic medical supplies for students.