Design of a Safer Tracheostomy Tube1

During a tracheotomy, the surgeon makes an incision through the front of the patient’s neck (the incision is known as a tracheostomy) to access the trachea and inserts a tracheostomy tube (see Fig. 1), which serves as an alternative airway to the mouth or nose. After insertion, a balloon is inflated to the diameter of the trachea, which fixes the tracheotomy tube in place, allows for positive pressure ventilation, and creates a seal to the walls of the trachea. Tracheotomies are a common procedure; approximately 120,000 procedures are performed each year in the U.S. [1]. There are several indications for a tracheotomy, but a review of 1130 cases spanning over a decade found that tracheotomies are done most often to assist in prolonged mechanical ventilation ( 76%). They are also performed as an adjunct to head, neck, and chest surgery ( 11%) and to relieve upper airway obstruction ( 6%). The same study identified major complications, such as tracheal stenosis (i.e., narrowing) or hemorrhage, 4% of the time, and attributed eight deaths directly to the tracheotomy [2]. Other studies have found complication rates as high as 45% [3]. We hypothesize that a portion of these complications is attributable to a suboptimal tracheostomy tube design. Currently, during tube insertion, the folds of the deflated balloon or the tip of the tracheotomy tube itself (which has rough edges) often get caught on cartilage (see Fig. 1) within the incision, which can prevent further insertion. This is one of the main difficulties of inserting the tracheostomy tube. To proceed, surgeons have two options: They can push the tracheostomy tube harder to force the tube through the incision, or they can remove the tube, open the incision further, and reattempt to insert the tube. The first option can be dangerous since large insertion forces can lead to “backwalling” (i.e., puncturing through the back of the trachea) or the creation of a false lumen (i.e., a new passageway for air), which can cause the side of the neck to inflate and close the trachea. The second option of widening the incision is also not desirable because surgeons prefer to keep the incision as small as possible, and it increases the procedure time, which is often very time sensitive, especially in cases of upper airway obstruction. In this paper, we propose a design addition to a conventional tracheostomy tube, where a thin, smooth membrane “umbrella” covers the distal end of the tube and the balloon. This membrane enables the device to be inserted through a predictable, repeatable incision size and prevents the tracheostomy tube tip and balloon features from catching on trachea cartilage, which facilitates easier insertion of the tracheostomy tube. After the tube has been inserted, this deformable membrane can quickly be pulled through the inside of the tracheostomy tube by deforming and inverting its umbrella-like shape. In what follows, we describe the design and manufacturing of this device. Fig. 1 A tracheostomy tube is inserted into the trachea through an incision on the neck. Once inserted, the balloon is inflated to secure the tube in the trachea and maintain the airway.