Tracheostomy inner cannula care: a randomized crossover study of two decontamination procedures

Today several methods for decontaminating inner cannulae exist. These methods are not based on scientific data, but often on local clinical tradition. This study compares two different decontamination methods. The aim was to find a practical and safe decontamination method. It is a randomized, single-blinded, comparative crossover study.

Fifty outpatients with long-term tracheostomy with an inner cannula were consecutively included and randomly allocated to begin with one of two different treatment sequences: detergent and chlorhexidine-alcohol (A) or detergent (B). Samples for bacterial culture were taken before and after decontamination, and the number of bacteria colonies was counted.

Before decontamination, the inner cannulae grew high numbers of bacteria, which were parts of the normal flora of the upper respiratory tract and did not differ significantly between the two sequences (AB; BA). The primary variable was the culture count value after chlorhexidine-alcohol/detergent (A) and detergent (B). The effects of both methods were larger than expected, and the results showed a nearly total elimination of organisms. The equivalence criterion, ratio of mean colony counts (A/B) >0.8, was met at a significance level of P<0.001.

Cleaning the tracheostomy inner cannula with detergent and water is sufficient to achieve decontamination.