Indirect Measurement of Laryngeal and Tracheal Resistance

Abstract

We used a body plethysmograph to determine airway resistances in 485 cases of laryngeal and tracheal stenoses. 143 cases who had resistances exceeding 60 mm H₂O/l·a·sec underwent surgery. A vocal cord was laterally fixed in 49 patients suffering from bilateral recurrent paralysis. Optimal results were obtained at a postoperative resistance level of 30 mm H₂O/l·a·sec (standard value: 14.77 ± 6.53 – n = 387). The patients could carry out work of medium intensity and had a steady voice. We performed tracheal interventions in 94 cases of tracheal stenoses. A mean postoperative resistance of 29.9 mm H₂O /l·a·sec, with a tracheal diameter of 7–8 mm was attained. In practice, only a few patients found the remaining obstruction a hindrance, during work of maximal intensity. No recurrences were observed after treatment. Airway resistances exceeding 150 mm H₂O /l·a·sec were found in 13 new admissions and 73 times in those undergoing therapy. In these cases, asphyxiation threatens. These patients must be tracheo-tomized or intubated immediatly.

Lung Function Changes and Exercise-Induced Ventilatory Responses to External Resistive Loads in Normal Subjects

“…A steady-state protocol was employed that imposed 80 and 160 W on the subjects breathing through an unloaded mouthpiece or through each of three external loads (10,8. and 6 mm orifice size) inserted in random order after 2 min of ventilation at rest.…”

“…It is of note, that Rp equal to or greater than 1.5 kPa-s/1 is thought to indicate severe respiratory compromise and even imminent asphyxiation [ 10], where laryngeal or tra cheal stenosis alone is involved.…”

Rhinomanometry – A Review

“…Alternating Pressure Method [Schumann and Mann, 1975], The airflow is conducted during expiration through a pneumotacho graph having a deliberately changeable resis tance inducing different partial pressures, proportional to the airway resistance. The drawback of this method is that breathing against a resistance can induce compliance changes1 in the cheeks, cartilaginous part of the nose and face mask.…”

Increased frequency dependence of specific airway resistance in patients with laryngeal hemiplegia

“…Any condition altering this fine relationship, such as lesions of the peripheral nerves, muscles or mucosa of the upper airway, can cause laryngeal dysfunction. The diagnosis of laryngeal dysfunction can be made by means of direct visualization, pulmonary function tests, electromyography, and various radiological techniques [1].An obstructive lesion of the upper airway from the carina to the epiglottis can produce changes in pressure on the airway wall and limit airflow. One of the most widely used pulmonary function tests for evaluating airflow limitation is the flow-volume loop (V9/V), with an analysis of forced inspiratory and expiratory flows, the configuration of which can categorize airway obstruction into one of three types: 1) variable extrathoracic obstruction; 2) variable intrathoracie obstruction and 3) fixed obstruction.…”

“…Any condition altering this fine relationship, such as lesions of the peripheral nerves, muscles or mucosa of the upper airway, can cause laryngeal dysfunction. The diagnosis of laryngeal dysfunction can be made by means of direct visualization, pulmonary function tests, electromyography, and various radiological techniques [1].…”