Endotracheal Tube: What is it? History, Purpose, Types, Characteristics and Risks

An endotracheal tube is an example of an artificial airway. A tracheostomy is another type of artificial airway.

“Endotracheal” means “through the trachea.”

The word intubation means “to insert a tube.” Generally, the word intubation is used to insert an endotracheal tube.

A tracheostomy tube is another type of tracheal tube; This 2–3 inch (51–76 mm) long curved metal or plastic tube can be inserted into a tracheostomy stoma (after a tracheostomy) to maintain a clear lumen.


An endotracheal tube is a flexible plastic tube placed through the mouth into the windpipe to help a patient breathe.

The endotracheal tube is connected to a ventilator, which delivers oxygen to the lungs. The process of inserting the line is called endotracheal intubation.

Portex medical (England and France) produced the first cuffless plastic ‘Ivory’ endotracheal tubes, along with Magill’s design, who later added a cuff as manufacturing techniques became more viable; they were glued by hand to make the famous Blue-line tube—copied by many other manufacturers.


Maeterlinck GmBH developed the disposable endotracheal tube and produced a host of design variations, adding the ‘murphy eye’ to their lines in the event of ‘accidental’ tube placement to avoid proper bronchial occlusion.

David S. Sheridan was one of the manufacturers of “disposable” plastic tracheal tubes in the US markets that are now commonly used in surgery.

Previously, red rubber tubes (Rusch-Germany) were used, then sterilized for reuse.


The breathing tube size is adjusted to your age and throat size. The tube is held in place by a small air cuff inflates around the line after insertion.

  • Years: preterm
  • Weight : 3 kg
  • Inner diameter in mm: 5–3.0
  • Years : 0–6 months
  • Weight : 3.5 kg
  • Inner diameter in mm : 0–3.5
  • Age: 6-12 months
  • Weight : 7 kg
  • Inner diameter in mm : 3.5–4.0
  • Years: 1–3 years
  • Weight: 10–12 kg
  • Inner diameter in mm: 4.0–4.5
  • Years : 4-7 years
  • Weight : 16–18 kg
  • Inner diameter in mm : 5.0–5.5
  • Years : 8-10 years
  • Weight : 24-30 kg
  • Inner diameter in mm : 5.5–6.5
  • Age: adult female
  • Weight : 30+ kg
  • Inner diameter in mm : 7.0-7.5
  • Age : adult male
  • Weight : 30+ kg
  • Inner diameter in mm : 8.0-9.0

Purpose of the endotracheal tube

An endotracheal tube can be placed when a patient cannot breathe on their own due to a medical emergency, serious illness, or during surgery when a general anesthetic is used. Some indications for endotracheal intubation include:

  • For general surgery: Under general anesthesia, the body’s muscles, including the diaphragm, are paralyzed, and the placement of an endotracheal tube allows the ventilator to do the work of breathing.
  • To remove a foreign body: If the windpipe is obstructed by a foreign body that is aspirated (breathed), an endotracheal tube may be placed to help remove the foreign object.
  • To protect the airway against aspiration: If someone has massive gastrointestinal bleeding (bleeding in the stomach) or has a stroke, an endotracheal tube may be placed to help prevent stomach contents from entering the airways.
  • To visualize the airway: If an abnormality in the larynx, trachea, or bronchi is suspected, an endotracheal tube may be placed to allow detailed visualization of the airway.
  • After lung cancer surgery: An endotracheal tube connected to a ventilator may be left in place to help with breathing after surgery.
  • To help to breathe: If someone has difficulty breathing due to pneumonia, a heart failure pneumothorax (collapsed lung), or loss of consciousness due to an overdose, stroke, or brain injury may be placed, and a tube may be placed endotracheal to facilitate breathing.

Types of the endotracheal tube

Endotracheal tube types include oral or nasal, cuffed or uncuffed, preformed (e.g., RAE tube (ring, Adair, and Elwyn)), reinforced tubes, and dual-lumen endobronchial tubes.

The tubes range from 2 to 10.5 mm in internal diameter (ID) for human use. The size is chosen based on the patient’s body size, and the smaller sizes are used for pediatric and neonatal patients.

Tubes larger than 6mm in internal diameter generally have an inflatable cuff. Originally made from red rubber, most modern lines are made from polyvinyl chloride. Those placed in a laser field can be flexo metallic.

Robertshaw (and others) developed dual-lumen endobronchial tubes for thoracic surgery. These allow ventilation of only one lung while the other lung is collapsed to facilitate surgery.

The deflated lung is re-inflated at the end of surgery to detect fistulas (tears).

Another type of endotracheal tube has a small second lumen opening above the inflatable cuff, which can be used to suction the nasopharyngeal area and above the cuff to aid extubation (removal).

This allows suction of secretions above the cuff, helping to reduce the risk of chest infections in long-term intubated patients.

“Shielded” endotracheal tubes are cuffed, wire-reinforced silicone rubber tubes that are relatively flexible but difficult to compress or twist.

This can make them useful for situations where the trachea is expected to remain intubated for an extended period or if the neck must remain flexed during surgery.

Polyvinyl chloride tubes are relatively stiff in comparison. Preformed tubes (such as RAE oral and nasal tubes, named after the inventor’s Ring, Adair, and Elwyn) are also widely available for specialty applications.

These can also be constructed of polyvinyl chloride or wire-reinforced silicone rubber. Other tubes (such as the Bivona Fome-Cuf tube) are specifically designed for use in laser surgery in and around the airways.

Several types of double-lumen (actually endobronchial) endotracheal tubes (Carlens, White, Robertshaw, etc.) have been developed to ventilate each lung independently; This is useful during lung operations and other thoracic operations.


Endotracheal tubes are made primarily of polyvinyl chloride (PVC) and only for single use. They have several characteristics that are listed below.

Many variations of these designs exist on endotracheal tubes for particular purposes, as described in the links to the left.

Tube tip design

Endotracheal tubes (ETTs) typically have a left-facing angle at the tip and Murphy’s eye as a second design feature.

The angle is oriented to the left and not to the right to allow the tip of the endotracheal tube to pass more quickly through the vocal cords. Endotracheal boxes are usually placed with the right hand in a right-to-left direction toward the larynx.

While a tube with a beveled tip is easier to pass through the vocal cords, it is more likely to be impeded when the opening contacts the tracheal wall.

Murphy’s eye provides an alternate gas path in the event of an occlusion.

Cuff design

Most endotracheal tubes used in the operating room are low-pressure, high-volume types. These cuffs have a comparatively large volume and consequently a large contact area between the cuff and the trachea.

When inflated, the cuff can develop folds in this contact area, increasing the risk of aspiration secondary to tracing of regurgitated fluid along these folds into the trachea.

In contrast, high-pressure, low-volume cuffs are believed to provide better protection against aspiration. Due to its much smaller cuff-trachea contact area and the higher inflation pressures used, cuff folds are less likely to develop.

The disadvantage of this type of cuff is that higher pressures are more likely to lead to ischemia of the tracheal mucosa. The sleeve of the laser tube is of a high-pressure, low volume design.

Other features

Polyvinyl chloride, the material from which most endotracheal tubes are made, does not absorb X-rays. Polyvinyl chloride tubes, therefore, contain a radiopaque line, which makes them visible on chest x-rays.

Additionally, most endotracheal tubes have a non-locking Luer connector pilot balloon and a metal spring valve through which the cuff can be inflated. The pilot balloon allows a visual and tactile assessment of whether the cuff is extended or not.

Tracheostomy tube

Several types of tracheostomy tubes are available, depending on the patient’s requirements, including Shiley, Bivona (a silicone tube with metal rings that are good for airways with damaged or non-straight tracheal rings), and fenestrated.

Endotracheal intubation

Endotracheal intubation is a medical procedure in which a tube is placed into the windpipe through the mouth or nose. Endotracheal intubation maintains an open airway and helps prevent suffocation.

In typical endotracheal intubation, you are given anesthesia. After endotracheal intubation, you will likely be placed on a breathing machine. Endotracheal intubation is done to:

Open the airway to give oxygen, medicine, or anesthesia. Support breathing in certain diseases, such as pneumonia, emphysema, heart failure, collapsed lung, or severe trauma.

Eliminate airway blockages. Allow the provider a better view of the upper airway.

It protects the lungs of people who cannot protect their airways and are at risk of inhaling fluid (aspiration). This includes people with sure strokes, overdoses, or massive bleeding from the esophagus or stomach.

How to do endotracheal intubation

The usual way to insert an endotracheal tube is through the mouth. This is called an oral endotracheal tube. Less commonly, the endotracheal tube is inserted through the nose. This is called a nasal endotracheal tube.

A soft, donut-shaped balloon sits around the outside of the endotracheal tube. This is called the “cuff.” The cuff is inflated with air, and it serves two purposes.

First, it reduces the number of verbal sections that can travel through the outside of the tube and into the lung. This is important because inserting an endotracheal tube into the airway will “snap” the epiglottis into an open position.

Although the cuff reduces the number of secretions entering the lung, it does not entirely prevent it. For this reason, ventilator patients are at risk of developing secretory pneumonia.

The second reason for the cuff is to prevent mechanical breaths from leaving the lung around the tube. When we give the patient a drag on the ventilator, we want the breath to go in and out of the box.

Without a cuff, the breath would enter the tube, but some would escape around the cuff before reaching the lung.

While the patient has an endotracheal tube, the cuff will need to be inflated. An inflated cuff will prevent the patient from speaking. Speech occurs when we exhale air through the vocal cords, causing them to vibrate.

Because the cuff blocks airflow around the tube, speech is not possible. Once the line is removed (called extubation), the patient will be able to speak.

The voice may sound hoarse, and the patient may have some discomfort in the throat for the first few days.

What are the risks of endotracheal intubation?

Some of the risks associated with the placement of an endotracheal tube include:

Bleeding Infection. Trauma to the voice box (larynx) or hoarseness, many people experience a sore throat after an endotracheal tube is placed.

For esophageal placement, an x-ray may be done to ensure the tube is placed in the windpipe and not the esophagus.

Risks of anesthesia

You will usually be under general anesthesia during the procedure. This means that you will not feel anything when the tube is inserted. Factors that can increase your risk of complications with anesthesia include:

Chronic lung, kidney, or heart problems, alcohol use, smoking, and age.

More severe complications can occur in older adults who have significant medical problems. These complications are rare but can include:

  • Heart attack.
  • Lung infection.
  • Temporary mental confusion
  • Death.

About one or two people in 1,000 may be partially awake under general anesthesia. If this happens, people are usually aware of their surroundings but will not feel any pain.

In rare cases, they may feel severe pain. This can lead to long-term psychological complications, such as post-traumatic stress disorder (PTSD).

An anesthesiologist or EMT ambulance will evaluate you before the procedure to help decrease the risk of these complications. You will also be carefully watched throughout the process.

Prevention of ventilation associated pneumonia (VAP) or aspiration (suffocation with secretions)

Pneumonia is a severe complication of mechanical ventilation and respiratory tubes.

Because the cuff on the breathing tube only reduces (does not prevent) secretions from passing out of the cuff, we have several other strategies that are part of the routine practice:

Special breathing tubes are used. Subglottic drainage tubes with a low continuous suction port over the cuff are used.

Oral care to reduce the number of oral bacteria. Oral care routine twice a day to lower the oral bacteria count. Daily assessment of readiness/attempt to minimize sedation.

Daily assessment of readiness / attempt to breathe spontaneously (without the support of the breathing machine). Early feeding within 24-48 hours unless contraindicated. The average elevation of the head of the bed.

Why is endotracheal intubation done?

Patients may need an endotracheal tube for one of several reasons. You may need this procedure for any of the following reasons:

To open your airways to receive anesthesia, medicine, or oxygen, to protect your lungs; if you have stopped breathing or are having difficulty breathing, you need a machine to help you live.

An endotracheal tube is needed to mechanically ventilate a patient (or breathe through a machine). Each breath goes into the endotracheal line and the lung.

If you have a head injury and cannot breathe independently, you need to be sedated to recover from severe injury or illness; endotracheal intubation keeps your airway open.

An endotracheal tube is also needed if the patient is unconscious or has a brain injury. The brain controls the reflex in the airway that prevents choking when we swallow or eat.

This reflex is called the gag reflex. The upper part of the windpipe has a special opening called the epiglottis. The epiglottis closes to prevent food from entering the windpipe when we swallow food.

This protective response is often impaired when patients are severely sedated, unconscious, or have a brain injury. Without a gag reflex, saliva would enter the windpipe. This is called aspiration. Aspiration is a severe complication and one of the causes of pneumonia.

A less common reason to intubate a patient is to keep the airway open. This is most often seen in patients with tumors or growths on the neck or upper chest.

The procedure may need to be done while the person is still awake with certain medical conditions. A local anesthetic is used to numb the airways to lessen discomfort. Your anesthesiologist will inform you before intubation if this situation applies to you.

How to remove an endotracheal tube

To ensure patient safety, the patient with a temporary artificial translaryngeal airway should remove the device as soon as possible.

Occasionally, acute obstruction of the artificial airway due to mucus or mechanical deformation requires immediate removal of the artificial airway.

The decision to remove an endotracheal tube (extubation) is made when the patient achieves adequate airway control. This requires an effective cough and an acceptable level of consciousness.

When the airway control provided by the endotracheal tube is deemed no longer necessary for ongoing patient care, the line should be removed.

In general, the patient must be able to maintain a patent airway and adequate spontaneous ventilation and must not require high levels of positive airway pressure to maintain normal arterial blood oxygenation.

Patients in whom additional medical care is considered (and explicitly stated) may have the endotracheal tube removed despite continued indications for the artificial airway.

Acute airway obstruction requires immediate removal of the endotracheal tube if the block cannot be cleared quickly.

Reintubation or other appropriate techniques to reestablish the airway should be used to maintain effective gas exchange (i.e., surgical airway management).

Professionals must identify when a patient is ready for endotracheal tube removal and recognize contraindications and potential complications.

The Glasgow Coma Scale should be used to assess the patient’s level of consciousness. Extubation should not be performed in patients with eight or less.

The patient is suitable for endotracheal tube removal if his peak expiratory flow rate is more than 60 L / minute.

Prolonged translaryngeal intubation is associated with many complications, including, but not limited to, sinusitis, vocal cord injury, laryngeal injury, laryngeal stenosis, tracheal injury, hemoptysis, and pulmonary infection.

Extubation can cause upper airway obstruction due to laryngospasm, laryngeal edema, supraglottic obstruction; pulmonary edema; pulmonary aspiration syndrome, or alteration of the exchange of respiratory gases.

The endotracheal tube should be removed in an environment where the patient can be physiologically monitored. The emergency team and appropriately trained healthcare providers with airway management skills are readily available.

There are no absolute contraindications to extubation; however, some patients will require reintubation, positive pressure ventilation, continuous positive airway pressure, noninvasive ventilation, or a highly inspired fraction of oxygen to maintain acceptable gas exchange after extubation.

Protective airway reflexes are generally depressed immediately after and for some time after extubation, and therefore measures to prevent aspiration should be considered.

Patients may require reintubation immediately or after some interval due to inadequate extubation, the progression of the underlying disease, or the development of a new disorder.

An extubation trial may be used in some marginal patients with the expectation that the need for reintubation is likely.

The need to reinsert an artificial airway after extubation is not necessarily an indication of malpractice. Inadequate maintenance of the airway and failure of reintubation may be an indication of malpractice.

The extubation complication and failure rates can be used as quality monitors.

The success of endotracheal tube removal can be monitored by examining the frequency of reintubation and complications.

When a patient experiences unplanned self-extubation and does not require reintubation, planned extubation should have been considered earlier.