Clinical Research and Publications New Unidirectional Airflow Ball Tracheostomy Speaking Valve Experimental Assessment and Future Applications of the Shikani Tracheostomy Speaking Valve Comparison of Speech Parameters and Olfaction Using Different Tracheotomy Speaking Valves The Shikani HME: A New Tracheostomy Heat and Moisture Exchanger Linear versus Turbulent Airflow Tracheostomy Heat and MoistureExchangers: A Crossover Study