At first glance, an endotracheal tube (ETT) might look like nothing more than a piece of plastic: hollow, simple, even unremarkable. But don’t be fooled. This device is a quintessential lifeline in a failing airway—a precision tool with critical design features you need to understand.

As part of the Vortex Approach, the ETT marks the pivotal transition from non-invasive methods, such as face mask ventilation and supraglottic airways, to a definitive airway solution. When all else fails, the ETT stands between your patient and hypoxic collapse.

To use it effectively for oxygenation and ventilation, you need to understand its key features and know how to deliver it safely from the package to its final destination between the cords. In this space, that’s exactly what we’ll show you how to do. Let’s begin.

Take a closer look, and you’ll find that the endotracheal tube has several key design features that make it far more than just a simple plastic tube. These details matter—and understanding them can help you use this tool more effectively in critical moments.

When you place an endotracheal tube, there are a few key things to get right. You need to choose the right size, place it at the correct depth, and ensure the tip ends up just above the carina. These steps are crucial because even if the tube goes through the cords, mistakes in size or position can still cause problems.

• Size Selection: Choosing the correct tube size is vital. While height is a strong predictor, there are no formal guidelines for adults. Always have a size above and below your estimated choice available during intubation.
• Depth Placement: Accurate depth placement is crucial for effective results. The common 23/21 rule (23 cm for men and 21 cm for women) often proves inaccurate. Instead, consider using the “Chula Formula,” which estimates the proper depth based on the patient’s height.
• Anatomical Positioning: Ideally, the ETT’s tip should be approximately 5 cm above the carina. This positioning helps prevent the tube from entering a mainstem bronchus, which could lead to uneven ventilation or collapse of the affected lung.

ETT size is usually a judgment call. While height appears to be a strong predictor, there are no formal guidelines for adults. Just in case, you should always have a size above and below the intended one available during your intubations.

Accurately predicting the correct depth is difficult. The common 23/21 rule (23 cm for men and 21 cm for women) is usually inaccurate. That’s because height is the most accurate predictor of appropriate tube depth. The more precise formula for estimating the insertion depth of an endotracheal tube in adults is known as the “Chula Formula.” This rule suggests that the proper depth of insertion of the endotracheal tube (in centimeters) at the patient’s teeth or gums is:

Generally, the ideal placement for the tip of the ETT is approximately 5 cm above the carina. This positioning helps prevent the tip from being lodged in one of the mainstem bronchi, which could lead to uneven ventilation or even lung collapse on the affected side.

You’ve got the basics down—great work! To keep learning, head to the next poster. Want to go deeper? Click Continue the Journey for extra clinical pearls, evidence reviews, and curated links to expand your learning network—or bookmark it and return anytime.

The endotracheal tube (ETT) is a fundamental tool in airway management, but its effectiveness depends on understanding its key design features and proper use. Every clinician who intubates should be familiar with tube selection, depth placement, and the anatomical considerations that influence successful intubation. Choosing the right size, ensuring accurate placement to avoid mainstem intubation, and recognizing the tube’s limitations in tracheal access are essential for safe and effective airway practice. Mastery of these principles enhances patient safety and improves outcomes in critical airway situations.