Intubation under anesthesia involves guiding a flexible tube through the mouth or nose to keep the airway open during surgery. The tube is threaded through the trachea to a point just above where it branches off to each lung. It is usually connected to a ventilator or other mechanical device that provides pressurized oxygen to each lung. Intubation under anesthesia typically prevents stomach acid from entering the airway and keeps respiratory gases from leaking.
A laryngoscope might be used to guide the endotracheal tube through the mouth or nasal passages. This fiber optic scope helps confirm placement of the tube as it weaves past the patient’s vocal cords. Doctors typically use a stethoscope during intubation under anesthesia to determine if each lung is receiving oxygen once the tube is in place. Instruments can also help measure the levels of oxygen and carbon dioxide.
Several types and sizes of tubes might be used, depending upon the patient’s size and physical characteristics of the mouth and throat. Doctors commonly use a standard scoring system to evaluate the difficulty of intubation under anesthesia for each patient. They measure the patient’s ability to keep the head tilted back, along with the alignment of the jaw. Anesthesiologists usually examine the amount of room in the throat and the size and shape of the tongue before intubation takes place.
Intubation tubes might be fitted with a balloon seal, called a cuff, to keep them in place. The exterior end of the breathing tube is fastened to the patient’s face during surgery. Early tracheal tubes were made from latex, but most modern devices are made from polyvinyl chloride to avoid allergic reactions to latex. Some tubes contain a port to deliver anesthesia medication during the operation.
A laryngeal mask airway device provides an alternative method of intubation under anesthesia, with less sore throat pain after surgery. This tube can be inserted without a laryngoscope, with one end resting over the sphincter muscles in the throat. The other end of the device sits at the base of the patient’s tongue.
Before intubation under anesthesia occurs, the patient receives drugs to render him or her unconscious, because the procedure can be quite uncomfortable. Medication to relax throat muscles makes insertion of the breathing tube easier. After surgery, the equipment is removed, a process called extubation.
Complications of intubation might include damage to tissue in the mouth, throat, or nose. Nasal bleeding might occur if adenoids are pierced during intubation. Aspiration of stomach contents represents a serious complication of the procedure, which is why most surgeries are performed on an empty stomach. In an emergency situation, this precaution might not be possible.