A cannula is basically a hollow tube that fits into some type of opening on the body to allow something, usually fluids or air, to be moved in or out of the hole. There are cannulas for a variety of purposes. A nasal cannula works to deliver oxygen to the noses of people who need to breathe a high concentration of oxygen. Liposuction cannulas are used to remove excess fat cells from a patient during certain medical procedures, usually performed by a plastic surgeon. A trach cannula is a type of tube used after a tracheotomy to keep the hole in the neck open and allow the patient to breathe.
Normally a person breathes through the nose and mouth, drawing air down into the lungs, and expelling it from the body. Sometimes a person’s airway is damaged by a fire or accident and it requires emergency surgical intervention to allow him or her to breathe. At other times the tracheotomy is performed because a person requires ventilation over a long period of time. It is much easier to supply air to a patient over the long term via a tracheostomy, the term for the hole in the neck, than to continually keep a tube inside the person’s throat that also blocks the mouth.
When a tracheostomy is made, a trach cannula is put in place so that the hole remains open. Otherwise it is possible for the opening to heal, cutting off the air flow to the patient. The trach cannula creates a passageway between the person’s windpipe and the outside of the body. Typically there are actually two tubes involved, an inner and an outer trach cannula.
The outer trach cannula is the piece that is actually in contact with the patient’s body. It is typically a short tube with a flange on the outer end that covers the opening in the neck. The inner tube fits into the opening of the outer tube and has a locking mechanism that holds the apparatus in place and makes sure that it is not dislodged by coughing or sneezing.
Removing the inner trach cannula periodically for cleaning is necessary to ensure that it doesn’t get blocked with phlegm or other body fluids. This is generally safe for the patient under controlled conditions, and is often necessary to keep the airway clear. Once the tube has been cleaned it can be replaced and hooked back up to the ventilating machine, if the patient is using one. The patient’s family is frequently trained to clean and replace the inner trach cannula.