title: Indirect estimation of laryngeal resistance via airflow redirection.
abstract: OBJECTIVE
  Our aim was to estimate aerodynamic parameters of laryngeal resistance (RL) and aerodynamic power indirectly from a subglottal pressure (Ps) data trace obtained with the airflow redirection system.
  
  
  METHODS
  During airflow interruption, the airflow redirection tank fills capacitively with pressure until it reaches the subject's Ps. Therefore, a time constant, tau, can be extracted from the data trace and used to calculate RL. The validity of applying this method to the estimation of RL was demonstrated with a computer model. Estimations were made for values of 10, 20, 30, 40, and 50 cm H2O per liter per second (L/s). Twenty subjects performed 10 trials on the experimental system designed to measure Ps. The values of RL and aerodynamic power were then calculated.
  
  
  RESULTS
  The computer model simulation yielded a maximum measurement error of 3.00% and a mean error of 1.78%. In human subject testing, the mean +/- SD laryngeal resistance was 22.61 +/- 8.65 cm H2O per L/s, the mean Ps was 6.91 +/- 1.94 cm H2O, and the mean aerodynamic power was 0.247 +/- 0.170 kPa x (L/s).
  
  
  CONCLUSIONS
  The proposed method of data analysis enables a clinician to estimate RL and aerodynamic power from a single experimental trial designed to measure Ps. This technique provides the clinician with an aerodynamic function report that can be used to analyze patient health and treatment efficacy.
authors.affiliation: Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA.
authors.forename: Adam L
authors.initials: AL
authors.lastname: Rieves
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Hoffman
authors.forename: Jack J
authors.initials: JJ
authors.lastname: Jiang