Tracheotomy is one of the most common surgical airway procedures performed in children. Approximately 5000 children undergo tracheotomy each year.1 In the past, tracheotomy was predominately performed in older children with acute upper airway compromise secondary to infection such as epiglottitis and croup.2 Currently, these acute upper airway infections represent less than 5% of tracheotomy performed in children.1,3 Tracheotomy is now more commonly being performed in children who require prolonged mechanical ventilation or who have significant anatomic rather than infectious causes of upper airway obstruction. The changes in the indications for tracheotomy reflect the extended survival of children born prematurely as well as those with chronic underlying illnesses such as neuromuscular disease and congenital anomalies.2–4 These underlying illnesses influence the etiology of tracheotomy-related infections encountered in children. This chapter focuses on the childhood tracheotomy-related infections of stoma cellulitis, tracheitis, and bacterial pneumonia.
Definition and Epidemiology
Tracheostomy stoma cellulitis is a bacterial infection of the epidermis lining of the tracheostomy opening. It is a dangerous infection that, if untreated, can spread contiguously through the tracheostomy site into the trachea or into the deep tissues of the neck and mediastinum. In the past, stoma infections occurred approximately in one-third of patients undergoing surgical tracheotomy placement.5 In more recent studies the rates of stoma infection have been significantly lower, ranging from 0% to 3%.6,7
There is limited information on the pathogens responsible for tracheostomy stoma cellulitis. It appears that the bacteria colonizing the granulation tissue surrounding the tracheostomy cause most cases of stoma cellulitis. The epithelial granulation tissue lining the tracheostomy site is colonized with bacteria by direct contact with the bacterial flora of the surrounding skin. Polymicrobial colonization has been reported in the majority of tracheostomy granulation tissue specimens, with a mixture of gram-positive, gram-negative, and anaerobic bacteria. Approximately 6 bacteria are detected in each granulation tissue specimen sent for culture.8,9 The bacteria most frequently recovered from granulation tissue culture include alpha-hemolytic streptococci, Staphylococcus aureus, Peptostreptococcus species, Bacteroides species, Fusobacterium species, and Pseudomonas aeruginosa.9,10 Most isolates produced beta-lactamase, including all isolates of S. aureus and Bacteroides species.9
The tracheostomy tube itself may also become colonized as it provides a portal of entry from the outside directly into the normally sterile trachea. Tracheostomy tubes are typically composed of plastic, with differing degrees of flexibility depending on the specific type of material (i.e., silicone or polyvinyl chloride). Bacteria with a polysaccharide shell can bond to the surface of a tracheostomy tube lumen, forming organized matrices of bacterial colonies. The colonies are often referred to as biofilm.11 The longer that a tracheostomy tube is used, the more likely that it will develop biofilm.
The bacteria that most frequently colonize the tracheostomy tube include S. aureus and P. aeruginosa...