Intubation is the placement of a flexible tube into the trachea (windpipe) to keep the airway open and allow a machine to push air into the lungs. The term almost always refers to endotracheal intubation, where a tube is passed through the mouth or nose, past the vocal cords, and into the trachea. It is one of the most common life-sustaining procedures in emergency rooms, operating rooms, and intensive care units, yet most people encounter it only when a loved one is critically ill or heading into surgery, and the mechanics can feel mysterious.
Why Someone Needs to Be Intubated
Intubation serves two core purposes: protecting the airway and delivering mechanical ventilation. In practice, doctors reach for an endotracheal tube whenever the body can no longer keep the airway open or the lungs can no longer move enough air on their own. In trauma patients, the recognized triggers include airway obstruction, inadequate breathing, persistent low oxygen levels despite supplemental oxygen, severe brain injury, major blood loss with shock, and cardiac arrest.1Journal of Trauma and Acute Care Surgery. Endotracheal Intubation Following Trauma Those same principles apply outside of trauma. A patient going under general anesthesia for a major surgery is intubated so the anesthesiologist can control breathing while paralytic drugs keep the muscles still. A patient in the ICU with severe pneumonia or respiratory failure may be intubated to buy the lungs time to heal.
The decision to intubate is not always black and white. In many emergency settings, the clinician weighs the patient’s level of consciousness, oxygen saturation, breathing effort, and the likelihood that the situation will deteriorate. A person who is unconscious and cannot protect their own airway from saliva or vomit needs intubation urgently, even if their oxygen levels are still acceptable at the moment.
How the Procedure Works
The most common approach in emergencies is called rapid sequence intubation, or RSI. It consists of seven steps: preparation, preoxygenation, pretreatment, paralysis with induction, protection and positioning, placement of the tube, and post-intubation management.2Emergency Medicine Clinics of North America. Techniques/Drugs that Can Assist in Intubation Challenges and Advances in Intubation: Rapid Sequence Intubation That sounds like a lot, but most of these steps happen within a few minutes.
Before anything touches the patient, the team gathers equipment: an endotracheal tube of the right size, a laryngoscope to see the vocal cords, suction to clear fluid, and monitoring devices. The patient breathes pure oxygen for a few minutes to build a reserve of oxygen in the lungs, buying extra seconds of safe time while the airway is being secured. Then a powerful sedative and a muscle relaxant are given intravenously, almost simultaneously. The sedative renders the patient unconscious; the muscle relaxant keeps the jaw, tongue, and vocal cords from tightening up. Etomidate and ketamine are the most commonly chosen sedatives because they tend to be gentler on blood pressure, and succinylcholine or rocuronium are the preferred paralytics.3PubMed. Pharmacotherapy optimization for rapid sequence intubation in the emergency department
Once the muscles relax, the clinician opens the mouth, slides a laryngoscope blade over the tongue, and lifts to expose the vocal cords. The endotracheal tube is then threaded between the cords and into the trachea. A properly placed tube sits with its tip at roughly the midpoint of the trachea, well past the vocal cords but above where the trachea branches into the two main bronchi.4Emergency Medicine Clinics of North America. Functional Anatomy of the Upper Airway The small balloon, or cuff, near the tube’s tip is then inflated to seal the airway. Finally, the tube is connected to a ventilator, and ongoing sedation and pain control begin.
Oral, Nasal, and Fiberoptic Routes
Most intubations are orotracheal, meaning the tube goes in through the mouth. This route gives the most direct path and the best visualization of the vocal cords. An alternative is nasotracheal intubation, where the tube enters through a nostril and curves down behind the palate into the trachea. Nasotracheal tubes are sometimes used in jaw surgeries or in patients whose mouths cannot open wide enough, but the technique carries its own risks such as nosebleeds and sinus complications.4Emergency Medicine Clinics of North America. Functional Anatomy of the Upper Airway
When anatomy makes standard laryngoscopy difficult, a flexible fiberoptic scope can be threaded through the nose or mouth with a camera at its tip. The clinician steers it into position under live video, then slides the endotracheal tube over the scope like a rail. Fiberoptic intubation is especially valued for patients with known difficult airways, such as those with limited neck movement, facial trauma, or tumors obstructing the throat.5PubMed. Fiberoptic intubation: an overview and update It takes more time and a steady hand, but it can succeed where other methods fail.
Video Versus Direct Laryngoscopy
Traditional laryngoscopy uses a metal blade with a light on the end; the clinician looks directly past the tongue to see the vocal cords. Video laryngoscopy puts a tiny camera at the blade’s tip and projects the view onto a screen, giving everyone in the room the same image. A large trial of over 1,400 critically ill adults found that first-attempt success was about 85% with a video laryngoscope compared with roughly 71% using a direct laryngoscope.6PubMed. Video versus Direct Laryngoscopy for Tracheal Intubation of Critically Ill Adults That 14-percentage-point difference is meaningful when every extra attempt increases the risk of low oxygen and aspiration.
The advantage of video laryngoscopy is most pronounced among less experienced operators. A randomized trial in an emergency department showed that medical students using video laryngoscopy achieved first-attempt success about 74% of the time, compared with 56% for those using a direct scope, while experienced clinicians performed similarly regardless of device.7PubMed Central. Direct Versus Video Laryngoscopy in Emergency Intubation: A Randomized Control Trial Study Complication rates between the two approaches appear similar overall, so the choice often comes down to availability and the operator’s comfort level. Many emergency departments have been shifting toward video laryngoscopy as the default first tool.
Confirming the Tube Is in the Right Place
A tube accidentally placed in the esophagus instead of the trachea is a feared and potentially fatal mistake. Several methods are used to verify correct placement, and no responsible clinician relies on just one. The classic technique is listening with a stethoscope: breath sounds should be equal on both sides of the chest and absent over the stomach. But auscultation alone is not reliable enough. One study of emergency intubations found that listening had a sensitivity of 94% and a specificity of only 83%, meaning it missed some misplaced tubes and falsely reassured clinicians about others.8PubMed. Comparison of three different methods to confirm tracheal tube placement in emergency intubation
The gold standard is continuous capnography, a device that measures carbon dioxide in exhaled breath. If the tube is in the trachea, you see a characteristic wave of CO₂ with every breath. If it is in the esophagus, you see none. In non-cardiac-arrest patients, capnography achieved perfect sensitivity and specificity in the same study.8PubMed. Comparison of three different methods to confirm tracheal tube placement in emergency intubation A larger meta-analysis of over 2,000 emergency intubations found capnography’s sensitivity was about 93% and its specificity about 97%, reflecting more challenging real-world conditions such as cardiac arrest, where low blood flow produces little CO₂ and can trick the device into suggesting an esophageal placement.9PubMed. Capnography alone is imperfect for endotracheal tube placement confirmation during emergency intubation For this reason, guidelines recommend using capnography in combination with clinical assessment and, when any doubt remains, a chest X-ray or direct visualization.
Cuff Pressure and Tracheal Damage
The inflatable cuff near the tip of the endotracheal tube seals the trachea so air does not leak around the tube and stomach contents cannot slide into the lungs. Keeping that cuff at the right pressure is a balancing act. Too low, and the seal fails. Too high, and the cuff squeezes the tracheal lining hard enough to cut off blood supply to the tissue underneath. Research dating back decades established that cuff pressures above 30 cm H₂O impair blood flow in the tracheal lining and recommended staying at or below that threshold.10British Medical Journal. Endotracheal cuff pressure and tracheal mucosal blood flow: endoscopic study of effects of four large volume cuffs
Even that guideline has limits. A study examining airway tissue in 100 patients under general anesthesia found that maintaining cuff pressure at 30 cm H₂O was safe during short procedures, but in patients who required long-term ventilation, mucosal damage still occurred and worsened the longer the tube stayed in.11PubMed Central. Reevaluating 30 cmH2O endotracheal tube cuff pressure: risks of airway mucosal damage during prolonged mechanical ventilation Tracheal injury from cuff pressure, though uncommon, is one of the more serious complications in anesthesiology and critical care.12PubMed Central. Endotracheal tube cuff pressure assessment: expectations versus reality ICU nurses and respiratory therapists typically check cuff pressure several times a day when a patient is intubated long term.
Risks and Complications
Intubation is generally safe, but it is not without risk. The most immediate danger during the procedure itself is a drop in oxygen levels, particularly in patients who are already sick. A multi-center study of helicopter emergency medical services found that roughly 3% of patients were still hypoxic at hospital admission after field intubation, and about 9-10% were hypotensive.13PubMed Central. Hypoxia and hypotension in patients intubated by physician staffed helicopter emergency medical services – a prospective observational multi-centre study These numbers highlight why preoxygenation and hemodynamic monitoring are treated as non-negotiable parts of the procedure.
The larynx is the most common site of airway injury during intubation, accounting for about a third of injury cases. Injuries at this level include granulomas (small nodules of inflamed tissue), bruising, vocal cord paralysis, and displacement of the small cartilages that control the vocal cords.14PubMed Central. Vocal cord paralysis after endotracheal intubation: an uncommon complication of general anesthesia Factors that raise the risk of laryngeal injury include a long intubation period, a difficult intubation requiring multiple attempts, and changes in the patient’s head or body position while the tube is in place.15PubMed Central. Laryngeal injury and dysphonia after endotracheal intubation Most of these injuries heal on their own within days to weeks, but vocal cord paralysis can occasionally be permanent.
Prolonged intubation, generally defined as lasting longer than seven days, brings its own set of complications.16IntechOpen. Long-Term Complications of Tracheal Intubation The longer a tube sits in the trachea, the greater the chance of infection, tracheal narrowing from scarring, and erosion of the tissue where the cuff presses. Ventilator-associated pneumonia is one of the most common and dangerous complications for patients intubated in the ICU. These risks are a major reason clinicians begin discussing alternative airway strategies if a patient cannot be weaned off the ventilator within a week or two.
When Intubation Gives Way to Tracheostomy
For patients who need mechanical ventilation for more than a couple of weeks, a tracheostomy, a surgical opening directly through the front of the neck into the trachea, often replaces the endotracheal tube. The tracheostomy tube is shorter, bypasses the mouth and larynx entirely, and is generally more comfortable for the patient. A study comparing the two approaches in critically ill patients who needed ventilation for more than 14 days found that those who received a tracheostomy had lower ICU mortality, lower in-hospital mortality, and a higher rate of successful weaning from the ventilator.17PubMed Central. Is tracheostomy a better choice than translaryngeal intubation for critically ill patients requiring mechanical ventilation for more than 14 days? A comparison of short-term outcomes The timing of tracheostomy, whether to do it early or wait, remains a topic of active debate in intensive care medicine.
A tracheostomy is not the only alternative to standard endotracheal intubation. In some rescue scenarios, particularly in newborn resuscitation, a laryngeal mask airway (a device that sits over the opening to the trachea without passing through the vocal cords) can provide a backup when both bag-mask ventilation and endotracheal intubation have failed.18Cochrane Database of Systematic Reviews. Laryngeal mask airway versus bag‐mask ventilation or endotracheal intubation for neonatal resuscitation These supraglottic devices are simpler to insert but do not seal the airway as completely as an endotracheal tube, so they are generally a bridge rather than a long-term solution.
Intubation in Children
Pediatric intubation follows the same principles as adult intubation, but children are not just small adults. Their airways differ in important ways. A child’s tongue is proportionally larger, the larynx sits higher in the neck, and the epiglottis (the flap that protects the airway entrance) is floppier and more angled. These features change the instruments and techniques an anesthesiologist might choose.19PubMed Central. Pediatric airway management
For decades, medical training taught that the narrowest point of a child’s airway was at the cricoid cartilage, the rigid ring just below the vocal cords, giving the airway a funnel shape. More recent imaging and bronchoscopy studies have challenged that model. The narrowest part may actually be at or just below the vocal cords themselves, and the airway is elliptical rather than circular in cross-section.20PubMed. Pediatric airway anatomy may not be what we thought: implications for clinical practice and the use of cuffed endotracheal tubes This updated understanding has driven a major shift in practice: cuffed endotracheal tubes are now used more frequently in children, including in infants and neonates, where uncuffed tubes were once the default. The newer cuffed tubes have thinner, softer cuffs that fit the elliptical airway shape more safely.
Training and the Human Factor
Intubation is a psychomotor skill, meaning it requires hands-on practice, not just book knowledge. Simulation-based training using mannequins and high-fidelity simulators has become a core part of how anesthesiologists and emergency physicians learn and maintain their airway management skills.21PubMed Central. Simulation-based Airway Management Training for Anesthesiologists – A Brief Review of its Essential Role in Skills Training for Clinical Competency This matters to patients because the single biggest predictor of intubation difficulty is often the operator’s experience rather than the patient’s anatomy. Video laryngoscopy’s biggest performance gains show up in less experienced operators, as noted earlier, which is partly why teaching hospitals have embraced it so quickly.
Simulation training also affects team behavior, not just individual technique. A study of simulated pediatric resuscitations found that after a two-day training course, the time teams spent on airway management decreased, reducing the pauses in chest compressions that can lower survival.22PubMed Central. To intubate or to resuscitate: the effect of simulation-based training on advanced airway management during simulated paediatric resuscitations Airway management during a cardiac arrest is a high-pressure, time-critical task where coordination among team members matters as much as the technical skill of the person holding the laryngoscope.
Advance Directives and the Decision Not to Intubate
Because intubation is a gateway to mechanical ventilation and often to prolonged ICU stays, it sits at the center of many end-of-life conversations. A “Do Not Intubate” (DNI) order, sometimes paired with a “Do Not Resuscitate” (DNR) order, is a legal directive that tells medical teams not to place an endotracheal tube if breathing fails. These decisions are deeply personal and can be documented in an advance directive or living will.
Honoring these directives is not always straightforward. A review spanning 20 years of legal and ethical cases found that health professionals have at times overridden patients’ explicit instructions against intubation and artificial ventilation, making this one of the most ethically charged areas in acute care.23PubMed. Overriding advance directives: A 20-year legal and ethical overview Overrides sometimes happen in chaotic emergency situations where the directive is not immediately available, when family members disagree, or when a clinician believes the patient’s condition is reversible. Having the conversation early, making sure the document is accessible, and designating a healthcare proxy all reduce the chance of an unwanted intubation. For patients with serious chronic illness, discussing intubation preferences with a physician long before a crisis is one of the most consequential planning steps they can take.
A Brief History of Intubation
The idea of placing a tube in the trachea is older than modern anesthesia. Andreas Vesalius reported the first tracheal intubation in an animal in 1543. It took more than three centuries for the concept to reach human medicine. In the early 1870s, the German surgeon Friedrich Trendelenburg performed the first endotracheal anesthesia in a human patient. In 1878, the Scottish surgeon William Macewen reported the first elective endotracheal intubation for the purpose of delivering anesthesia. The invention of the anesthetic laryngoscope by Chevalier Jackson in 1913, later refined by Magill, Miller, and Macintosh, gave clinicians a practical tool for visualizing the airway. The real turning point came in 1942, when curare was introduced as a muscle relaxant for surgery, making endotracheal intubation a routine part of major operations rather than a desperate rescue measure.24PubMed Central. Tracheostomy and endotracheal intubation: a short history The Macintosh curved blade, designed in the 1940s, is still one of the most widely used laryngoscope blades in the world, a testament to how well the fundamental ergonomics of the procedure were worked out early on.