An ET tube, short for endotracheal tube, is a flexible plastic tube placed through your mouth or nose and into your windpipe (trachea) to keep your airway open and deliver air directly to your lungs. It’s one of the most common devices used in hospitals, appearing in operating rooms during surgery, in emergency departments, and in intensive care units when a patient can’t breathe adequately on their own.
What an ET Tube Does
The tube creates a direct, sealed pathway between a ventilator or breathing bag and your lungs. This serves two critical purposes: it ensures oxygen reliably reaches your lungs, and it prevents fluids like saliva, blood, or stomach contents from entering your airway. Without this seal, patients who are unconscious or heavily sedated could aspirate those fluids into their lungs, leading to serious infections like pneumonia.
ET tubes are used during general anesthesia for surgery, in emergencies where someone has stopped breathing or can’t maintain their airway, and for patients in the ICU who need mechanical ventilation for days or even weeks. Severe trauma, respiratory failure, cardiac arrest, and drug overdoses are all common reasons someone might need one.
Parts of the Tube
A standard ET tube looks simple, but each part has a specific job. The tube itself is a curved, semi-rigid plastic cylinder, typically 25 to 35 centimeters long for adults. Near the tip that sits inside your trachea, there’s an inflatable cuff, a small balloon that forms a seal against the walls of your windpipe. This cuff prevents air from leaking out and stops secretions from sliding past the tube into your lungs.
Connected to the cuff is a thin line running along the outside of the tube to a pilot balloon, which stays outside your body. Medical staff squeeze this pilot balloon to gauge whether the cuff is properly inflated. At the opposite end, outside your mouth, is a standard connector that attaches to a ventilator or manual breathing bag. Many tubes also have a small side hole near the tip called a Murphy eye, which allows airflow to continue even if the main opening gets partially blocked by mucus or the tracheal wall.
How the Tube Is Placed
The process of inserting an ET tube is called intubation. Before it begins, you receive medications through an IV to put you to sleep and prevent pain. An oxygen mask is placed over your face to build up your oxygen levels beforehand.
The provider tilts your head back and uses a tool called a laryngoscope, a lighted handle with a smooth blade, to gently move your tongue aside and lift the tissue at the back of your throat. This exposes your vocal cords, which sit at the entrance to your trachea. The tube is then guided between the vocal cords and advanced a few centimeters into the windpipe. Once in position, the cuff is inflated with a small syringe of air, and the tube is secured to your face with tape or a strap.
The entire process typically takes under a minute in experienced hands, though difficult airways can take longer.
Confirming Correct Placement
Getting the tube into the right spot matters enormously. If it accidentally goes into the esophagus instead of the trachea, no oxygen reaches the lungs. If it’s pushed too far down, it can slip into one of the two main lung branches and ventilate only one lung.
The gold standard for confirming placement is waveform capnography, a monitor that detects carbon dioxide in exhaled breath. If the tube is in the trachea, the monitor picks up CO2 with every breath cycle, reaching nearly 100% sensitivity and specificity in studies. Ultrasound is also highly accurate and can distinguish between a tube that’s in the trachea versus one that’s gone too deep into a single lung branch. A chest X-ray is typically taken afterward to verify the exact depth of the tube.
Sizing for Adults and Children
ET tubes come in a range of sizes measured by their internal diameter in millimeters. Adult women generally use a 7.0 to 7.5 mm tube, while adult men typically need a 7.5 to 8.0 mm tube. Using the wrong size increases the risk of complications: too large and it can damage the airway lining, too small and it creates excessive resistance to airflow and may not seal properly.
Sizing for children is more precise because their airways change rapidly with growth. For children older than two, providers often use a formula based on the child’s age: divide the age by four and add 3.5 for a cuffed tube. A four-year-old, for example, would get approximately a 4.5 mm tube. Infants under six months typically use a 3.0 mm tube. Providers always keep one size larger and one size smaller on hand in case the calculated size doesn’t fit.
Cuff Pressure and Why It Matters
The inflatable cuff is one of the most important safety features of an ET tube, but it has to be inflated to just the right pressure. Too little pressure allows secretions to leak past the cuff and into the lungs, which is the single biggest risk factor for ventilator-associated pneumonia. Too much pressure compresses the blood vessels in the tracheal wall, cutting off blood flow to the tissue. Over time, this can cause tissue death and scarring.
The traditional safe threshold has been 30 cmH2O, but newer research suggests that even this level may cause airway mucosal damage during prolonged ventilation. Studies have found that a pressure closer to 25 cmH2O may be the sweet spot for preventing tissue injury while still maintaining a seal. In ICU settings, cuff pressure is checked regularly with a small handheld gauge. Proper cuff pressure also protects the recurrent laryngeal nerve, which controls the vocal cords. Damage to this nerve from excessive cuff pressure can cause hoarseness or voice loss.
Risks and Complications
Short-term complications are relatively common but usually minor. Sore throat affects roughly 30% of patients after the tube is removed. Hoarseness and mild swelling of the vocal cords typically resolve within a few days to weeks.
More serious complications are rarer but significant. The tube can chip or damage teeth during insertion. In rare cases, the tube or cuff can injure the vocal cords or the recurrent laryngeal nerve, leading to longer-lasting voice changes or vocal cord paralysis. Patients on prolonged ventilation face a risk of ventilator-associated pneumonia, which increases ICU stays and mortality.
The most concerning long-term complication is tracheal stenosis, a narrowing of the windpipe caused by scar tissue forming where the cuff sat. The reported incidence ranges from 1% to 11% after intubation. What makes this complication especially tricky is the timeline: it can take 8 to 10 years from the original intubation before the narrowing becomes severe enough to cause symptoms and get diagnosed. By that point, the connection to a past intubation is often overlooked.
How It Differs From a Laryngeal Mask Airway
A laryngeal mask airway (LMA) is an alternative device that sits above the vocal cords rather than passing through them. It’s easier and faster to place, doesn’t require a laryngoscope, and causes less airway trauma. Postoperative sore throat rates are notably lower with an LMA, around 12.5% compared to 30% with an ET tube in one clinical trial.
However, an LMA doesn’t create the same airtight seal in the trachea, which means it can’t protect the lungs as reliably from aspiration. It’s generally used for shorter, less complex surgeries in patients who haven’t recently eaten. For longer procedures, emergencies, or anyone at risk of vomiting, an ET tube remains the more secure choice. An LMA also serves as an important backup: if intubation with an ET tube fails, providers can place an LMA to maintain breathing while they reassess.
What Happens While You’re Intubated
If you’re intubated for surgery, the tube is usually removed as soon as the procedure ends and you’re breathing reliably on your own. You’ll likely wake up with a sore throat and a hoarse voice, both of which are normal and temporary.
For patients in the ICU on longer-term ventilation, the tube requires ongoing maintenance. Secretions build up inside the tube and in the airway, so nurses periodically suction through the tube to keep it clear. Current guidelines recommend suctioning only when there are specific signs of mucus buildup, such as visible secretions, changes in ventilator readings, or drops in oxygen levels, rather than on a fixed schedule. In-line suction catheters, which stay connected to the ventilator circuit, are generally preferred because they avoid disconnecting the patient from the breathing machine.
If a patient needs mechanical ventilation for more than two to three weeks, doctors typically recommend a tracheostomy, a surgical opening in the front of the neck, to replace the ET tube. This is more comfortable for the patient, easier to manage, and reduces the risk of the long-term tracheal damage associated with a tube passing through the mouth and vocal cords.