An endotracheal tube has a proximal end and a distal end and includes a tracheal portion having an opening at the proximal end and a bronchial portion attached at an angle to the tracheal portion. The bronchial portion has an opening at the distal end of the endotracheal tube. A balloon is positioned within the endotracheal tube that blocks the flow of a gas through the bronchial portion of the endotracheal tube when inflated. The endotracheal tube has an opening between the proximal end and the balloon. The opening is positioned to allow ventilation of the lung opposite the lung into which the bronchial portion is adapted to extend into. The endotracheal tube may include a carinal seating mechanism which may be located near the junction between the tracheal portion and the bronchial portion of the endotracheal tube. The endotracheal tube further may also include an inflatable bronchial extension tube. It is a common practice to provide human medical patients with artificial ventilation during surgery or in emergency situations. For example, accident victims will frequently require CPR or intubation by a paramedic in an emergency vehicle or by an anesthesiologist in an operating room. There are other surgical procedures which require use of an endotracheal tube to collapse one lung. For example, taking a biopsy from the lung to gather information on an infection, repairing a lobar defect due to infant emphysema, removing tumors, repairing an abscess or doing an esophageal triage. Generally, an endotracheal tube for collapsing one lung requires two separate passages, or "lumens".

Intubation is accomplished by insertion of an endotracheal tube through the patient's mouth or nasal passages into the airway passage. Such devices have generally comprised a relatively pliable tube with means for connecting it to a respirator or other air supply mechanism for introduction of air into the lungs. An improvement to endotracheal tubes includes an inflatable/deflatable bag-like structure or balloon "cuff" around the exterior of the tube. The balloon cuff is conventionally located in a position along the endotracheal tube to engage the inner wall of the pharynx, larynx, or trachea depending upon the specific endotracheal tube design. When the tube is in place, the cuff is inflated and forms an air tight seal between the tube and the surrounding body tissue to prevent the escape of air pumped from the respirator into the lungs.

Both single lumen and double lumen endotracheal tubes are known. Typically, a single lumen endotracheal tube is an elongated tube that extends into the trachea of a patient upon intubation and includes one inflatable balloon cuff near its distal end. Commonly, the double lumen endotracheal tube is referred to as an endobronchial tube and, in addition to one lumen which extends to the trachea, has a second longer lumen which extends into the bronchus of a patient upon intubation. Typically, the double lumen endotracheal tube or endobronchial tube includes two inflatable balloon cuffs. The so-called double lumen endobronchial tubes, such as the well known "Carlens" and "Robertshaw" tubes, allow for independent control of each lung through the separate lumina. One bronchus may be blocked by occluding one of the lumina at a position external to the patient, in order to isolate a particular lung.

The balloon cuffs are thin walled, high volume, and low pressure chambers or vessels which are designed not to compromise the blood flow in the tracheal or bronchial wall when inflated. Balloon cuffs are inflated by detachable syringes that are connected to smaller lumina or channels at the proximal end of the endotracheal tube. The seals formed by the inflated cuffs preclude the air that has been forced into the patient's lungs from escaping through the trachea or bronchus. Additionally, the seals formed by the inflated cuffs provide a barrier to the flow of blood, mucus, and secretions.