I agree with TraumaSurfer. While patients with artificial airways should be suctioned at regular intervals, these intervals should be determined based upon the patient and their presentation, rather than a fixed interval (i.e., every two hours). For a patient with an established tracheostomy, this might be as infrequently as once a shift with their routine tracheostomy care. Patients with new tracheostomies, or with an acute process, might require suctioning hourly, or more frequently. However, if the patient is able to cough and expel secretions through his tracheostomy tube, then they likely do not need to be suctioned. While patient's with tracheostomy tubes, particularly those that are capable of expelling their secretions, sound horrible, all that might be necessary is cleaning the exterior portion of the tracheostomy.
When you do suction the tracheostomy, you should never perform "deep suction;" rather you should only pass the suction catheter to where the tip of the suction catheter is even with, or slightly beyond, the tip of the tracheostomy tube. When you suction any artificial airway, all you are doing is clearing secretions from the inner lumen of the tracheostomy tube. Performing deep suctioning can damage the tracheal or bronchial lumen.
There are several resources available on line. While I haven't reviewed the entire site, the Tracheostomy Training Resources
; created by the National Tracheostomy Safety Project
seems to be a fairly extensive. There is an updated version available on their resources
, but it is a large file, and I haven't downloaded it yet. In addition to the resources available, they also maintain a YouTube channel, NTSP 2010 Channel