Long-term tracheostomy : outcome, cannula care, and material wear

Abstract

Do people with long-term tracheostomy need hospital care? Which cleaning method is most appropriate for decontamination of inner cannulae? Are tracheostomy tubes changed for rational reasons? There is clearly a lack of evidence based research in this field and the clinical guidelines available are often based on local practice. A tracheostomy is a created opening in trachea to facilitate breathing. It is a direct entry to the deeper airways, e.g. for micro-organisms causing a potential risk for lung infections. Indications for long-term tracheostomy can be, e.g. upper airway obstruction, malformations, or chronic hypoventilation, when ventilation via nasal mask is not possible. The research of the present thesis was conducted at the National Respiratory Centre (NRC) at Danderyd Hospital in Stockholm, Sweden. This unit opened in 1982, with the expressed goal of supporting outpatients with long-term tracheostomy. The overall aims of the thesis were to evaluate the outcome of patients with long-term tracheostomy and to conduct evidence based studies concerning their care.

A comparison was made for the number of days in hospital care during the 2-year periods before and after the tracheostomy was established. The life expectancy of the general population and the observed life span of a cohort of tracheostomized patients from the start of NRC in 1982 were also compared. Interestingly enough, the need for hospital care was unchanged despite of the tracheostomy. The patients observed life spans were remarkably high and for many patients not lower than the life expectancy of Swedish people in general.

To find a practical and safe decontamination method for inner cannulae we compared two different cleaning methods; detergent followed by chlorhexidine-alcohol, or detergent alone. Samples for bacterial culture were taken before and after cleaning and the numbers of bacteria colonies were counted. The effectiveness of both cleaning methods was greater than expected and the results showed a nearly total elimination of organisms. Thus, the methods investigated were equivalent in achieving decontamination.

The duration of use in our unit for polymeric tracheostomy tubes, i.e. silicone (Si), polyvinyl chloride (PVC), and polyurethane (PU) was determined and compared. We found, that Si tubes were used for longer periods (three months) than tubes made of PU or PVC (both two months).

Whether or not surface changes could be observed on the tracheostomy tubes after 30 days , three and six months exposure in the trachea were investigated in collaboration with the Royal Institute of Technology and Sophiahemmet University College in Stockholm, Sweden. The analyzing methods were Scanning Electron Microscopy, Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy, and Differential Scanning Calorimetry. All tubes, except one, showed changes in the surface after 30 days exposure. The surface changes had progressed significantly after three and six months' exposure, compared to the changes detected after 30 days. The SF-36 questionnaire and a study specific questionnaire were used to describe the patients health-related quality of life and experiences of long-term tracheostomy. The results show that all patients were satisfied with their tracheostomy and demonstrated a numerically mean mental health status score above that of the general population.

In summary, long-term tracheostomy does not increase the need for hospital care nor does it reduce a patient s life span. Cleaning the tracheostomy inner cannula with detergent and water is sufficient to achieve decontamination. Si tracheostomy tubes are used longer compared to those made of PVC or PU. The polymeric material investigated suffered evident surface changes after 30 days use. Clinical use of polymeric tracheostomy tubes beyond three months cannot be recommended, as we found extensive surface changes and degradation of the polymeric chains. All patients were, in general content, with their tracheostomy. The findings from the present thesis contribute to making the care of long-term tracheostomized patients evidence based.