An endotracheal tube (ETT) is a flexible, plastic medical device placed temporarily into the trachea (windpipe) to secure a patient’s airway and ensure a direct path for air to reach the lungs. It acts as the essential connection point for a mechanical ventilator. The ETT allows medical professionals to maintain complete control over a patient’s breathing, delivering oxygen and anesthetic gases directly without leakage. Securing the airway with an ETT is a common procedure performed in emergency settings, intensive care units, and operating rooms worldwide.
Anatomy and Function of the Endotracheal Tube
The structure of the ETT is specifically designed to function as a sealed conduit to the lungs. The main body, or shaft, is typically made of medical-grade polyvinyl chloride and features centimeter markings that aid clinicians in confirming the proper depth of insertion once placed. At the patient end of the tube is an inflatable cuff, a balloon-like structure that, once inflated with air, forms a seal against the inner wall of the trachea. This seal is crucial because it prevents air from escaping during mechanical ventilation and protects the lungs by blocking the aspiration of stomach contents, blood, or secretions.
The cuff is connected to a thin inflation line that runs alongside the main shaft of the tube to the outside. This line terminates in a valve and a small, external pilot balloon. The pilot balloon provides a visual indication of the cuff’s inflation status, confirming that the internal cuff is also inflated. The valve allows a syringe to be attached for controlled inflation or deflation, ensuring pressure is maintained within a safe range (often below 30 cm H₂O) to minimize injury to the tracheal lining.
Medical Conditions Requiring Intubation
ETT placement is necessary when a patient cannot breathe adequately or protect their airway reflexes. A common scenario is general anesthesia for major surgery, where a muscle relaxant is administered, temporarily paralyzing the patient’s respiratory muscles and necessitating controlled ventilation. The tube also provides airway access for procedures requiring the patient’s head to be positioned in a way that might otherwise compromise breathing.
Acute respiratory failure is a frequent reason for intubation, occurring when the lungs fail to maintain sufficient oxygen levels or remove carbon dioxide effectively. This can stem from conditions like severe pneumonia, an exacerbation of Chronic Obstructive Pulmonary Disease (COPD), or Acute Respiratory Distress Syndrome (ARDS). When the work of breathing becomes too exhausting, the ventilator takes over, allowing the lungs and respiratory muscles to rest and recover.
Trauma and neurological impairment also necessitate ETT use for airway protection. Patients with severe head injuries, drug overdoses, or strokes often have a significantly reduced level of consciousness, frequently measured by a Glasgow Coma Scale (GCS) score below eight. This loss of consciousness impairs protective reflexes, such as coughing and swallowing, placing the patient at high risk for aspiration of stomach contents into the lungs. Intubation creates a secure barrier against aspiration, which is a significant cause of lung infection.
The Intubation Procedure and Patient Management
The placement of the ETT, known as endotracheal intubation, is a rapid medical procedure often performed after administering specific medications. To ensure patient comfort and facilitate the process, a combination of sedatives and muscle-paralyzing agents is typically given intravenously. The clinician then uses a specialized instrument called a laryngoscope to visualize the vocal cords.
Using the laryngoscope to lift the epiglottis and expose the trachea, the ETT is carefully guided through the mouth and past the vocal cords into the windpipe. Once the tube is in place, the cuff is immediately inflated to secure the position and seal the airway. Correct placement is quickly verified using multiple techniques, including listening for equal breath sounds over both lungs and, most reliably, by monitoring for the presence of carbon dioxide in the patient’s exhaled breath, known as end-tidal CO2 monitoring.
Following successful intubation, the patient requires continuous, intensive management while on mechanical ventilation. Monitoring involves constant assessment of oxygen saturation, heart rhythm, and blood pressure to ensure stability. Sedation is maintained to keep the patient comfortable and prevent accidental tube removal, while ventilator settings are continuously adjusted to meet the patient’s needs for oxygenation and carbon dioxide removal.
Extubation and Recovery Challenges
When the underlying medical condition has resolved and the patient demonstrates sufficient strength, the ETT is removed in a procedure called extubation. Readiness is assessed through criteria including a return of consciousness, hemodynamic stability, and the ability to breathe adequately during a spontaneous breathing trial (SBT). The cuff is deflated, and the tube is withdrawn, marking a major step toward recovery and liberation from the ventilator.
The period immediately following tube removal can present several challenges as the airway recovers. A temporary sore throat and hoarseness are common, resulting from the tube passing through the vocal cords. Some patients may experience difficulty swallowing, or dysphagia, which can increase the risk of aspiration of food or liquids.
A more serious complication is the development of stridor, a high-pitched, harsh breathing sound caused by swelling (edema) in the upper airway. If the stridor is severe, it can cause significant breathing difficulty and may require the patient to be reintubated for a short period to allow the swelling to subside. Careful monitoring in the hours after extubation is therefore necessary to detect any signs of respiratory distress.