Physical and aerodynamic features of the Bordeaux voice prosthesis

Performance of a voice prosthesis, used to restore speech in patients following total laryngectomy, was evaluated by measuring in vitro, as well as in vivo, airflow resistances. The pressure-flow characteristics of the device were analyzed using the standard pressure-flow diagram (to calculate airway resistance) and a Moody plot (to determine the different flow patterns). The flow rate and the pressure drop were measured with a Fleisch pneumotachograph and a variable reluctance transducer, respectively. Total device resistances were found in the range of 34-50 cm H2O/L/s when the flow-rates ranged from 0.05 to 0.35 L/s. Comparison of these resistances with those of other commercially available devices showed that our voice prosthesis had the lowest resistance.