A prospective retrieval study to determine how speaking valve failure is effected by colonization
INTRODUCTION: It has been suggested that Groningen Low Resistance (GLR) valve failure is associated with biofouling of the valve's oesophageal surface and hinge areas. However, the valve edges are responsible for efficient valve function.1 Therefore, valve edge colonization should be the most important factor determining valve failure. The null hypothesis that valve edge colonization was not associated with failure was tested using 106 GLR valves retrieved, after failure, from 41 patients. METHODS: The opening pressures, reverse opening pressures and forward resistances of the new valves were determined using apparatus validated previously.2 The pressure/flow parameters were measured again after removal and the changes calculated. The degree of colonization of each valve edge, oesophageal surface, hinge area, tracheal surface and valve lumen was scored using 100-mm linear analogue scales. The changes, in pressure/flow parameters were examined for associated with colonization of the five areas described above. RESULTS: The increase in the opening pressure and resistance, and decrease in reverse opening pressure, of the retrieved valves was significant compred with new valves. The increase in opening pressure was associated with colonization of the valve edge (rs = 0.262, P = 0. 007). The decrease in reverse opening pressure was associated with colonization of the valve edge, hinge areas and oesophageal surface (rs = 0.266, P = 0.006; rs = 0.271, P = 0.005; rs = 0.271, P = 0.004, respectively). The increase in resistance was associated with colonization in all areas (rs >/= 0.367, P = 0.0005). CONCLUSION: This study demonstrated that colonization of the valve edge is associated significantly with the changes, in pressure/flow parameters of failed valves.
Ell
SR
Department of Otolaryngology, University of Hull, Hull and Department of Otolaryngology, Royal Hallamshire Hospital, Sheffield, UK).
Davies
CM
Parker
AJ