Anatomy of the Endotracheal Tube (ET Tube) - Airway Management

Summary

This video lesson, presented by Eddie Watson from ICU Advantage, covers the basics of the endotracheal tube (ETT), a crucial tool used in ICU settings for respiratory support. Eddie explains the structure, history, and various components of the ETT, highlighting its role in facilitating ventilation and preventing secretions from entering the lungs. He also discusses different types of cuffs, potential complications like ventilator-associated pneumonia, and the importance of proper tube sizing. The lesson provides a foundation for understanding ETTs before diving into intubation in the next lesson.

Takeaways

• 🫁 The endotracheal tube (ETT) is a vital tool used in the ICU to facilitate breathing and ventilation for critically ill patients.
• 🛡️ ETT helps protect the airway from secretions and gastric contents by sealing it off with an inflatable cuff.
• 💡 The material used for ETT is typically polyvinyl chloride (PVC), which is transparent, flexible, and non-toxic.
• 📏 ETTs come in different sizes, ranging from 2.0 to 12.0 mm, with the size based on the patient’s needs and anatomy.
• 🔍 ETTs have radio-opaque lines along their length for visibility during X-rays, helping confirm proper placement.
• 🛑 Risks associated with ETT use include infection (particularly ventilator-associated pneumonia), bleeding, and tracheal injury from prolonged use.
• 🔄 The tube is curved with a 'McGill curve' to make insertion easier by following the natural anatomy of the airway.
• 🎈 ETTs have two types of cuffs: high-pressure/low-volume and low-pressure/high-volume, the latter being more commonly used in ICUs to reduce tracheal injury.
• 🧪 A Murphy’s eye is an extra opening near the tip of the ETT to allow airflow in case the main opening gets blocked.
• 📉 Subglottic secretion suction systems can be added to some ETTs to reduce the risk of ventilator-associated pneumonia.

Q & A

What is the primary purpose of an endotracheal tube (ET tube)?

The primary purpose of an endotracheal tube is to maintain an open airway by providing a secure passage for ventilation, especially in patients requiring respiratory support, while also protecting the airway from secretions and gastric contents.

What is the material typically used to manufacture ET tubes, and why?

ET tubes are typically made of polyvinyl chloride (PVC), which is a transparent, non-toxic, flexible, and inexpensive material, making it ideal for medical use.

What are some variations in the types of ET tubes available?

There are both basic and more complex ET tubes. Some complex versions offer additional functions, such as isolating one lung from the other, which is particularly useful during pulmonary surgeries.

What is the significance of the 'Murphy's eye' in an ET tube?

The 'Murphy's eye' is an extra opening near the distal end of the ET tube that allows gas to pass through in case the tube's main opening becomes occluded, helping ensure continuous ventilation.

Why is the ET tube's cuff important, and what are the two main types of cuffs?

The cuff on an ET tube seals off the trachea, preventing air leakage during ventilation and protecting the lungs from secretions or gastric contents. The two main types of cuffs are high-pressure low-volume cuffs, which have a higher risk of tracheal injury, and low-pressure high-volume cuffs, which are safer and commonly used in ICUs.

How are ET tube sizes determined and what do the numbers represent?

ET tube sizes are determined by the internal diameter of the tube, measured in millimeters. For example, a typical size for adult women is 7.0–7.5 mm, while for men it ranges from 7.5 to 8.5 mm. The size is chosen based on the patient's size and the need for procedures like bronchoscopy.

What is the 'McGill curve' on an ET tube, and why is it important?

The 'McGill curve' is the natural curve in the ET tube that follows the anatomy of the upper airway. This design helps facilitate easier insertion of the tube into the patient's trachea.

What is subglottic secretion suction and how does it help in preventing ventilator-associated pneumonia (VAP)?

Subglottic secretion suction is a feature in some ET tubes that applies low suction to remove secretions that accumulate above the cuff. This helps prevent these secretions from entering the lungs, reducing the risk of ventilator-associated pneumonia by up to 50%.

What are some risks and complications associated with using an ET tube?

Risks of ET tube use include infection, particularly ventilator-associated pneumonia (VAP), tooth dislodgement, bleeding, esophageal placement, vocal cord damage, and tracheal mucosa ischemia due to high cuff pressure over long periods.

Why is it important to monitor cuff pressure and what can happen if the cuff is overinflated?

Monitoring cuff pressure is crucial to avoid overinflation, which can lead to complications like tracheal mucosa ischemia or even cuff rupture. The recommended cuff pressure is 20 cmH2O or less, and a manometer should be used to measure it accurately.