EFFECT OF LIDOCAINE ON THE VENTILATORY AND AIRWAY RESPONSES TO EXERCISE IN ASTHMATICS

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Abstract
An aerosol of 4% lidocaine was delivered during the last 1/3 of inspiration to patients with bronchial asthma while they were quietly breathing. After this procedure, both cough reflex (inhalation of 10% citric acid) and gag reflex (mechanical irritation of the larynx) were absent in all patients for 15-20 min. This type of anesthesia was tolerated well by all patients, and did not significantly influence baseline pulmonary function tests. On another day, this procedure was used prior to treadmill exercise testing. Anesthesia blocked the development of exercise-induced bronchoconstriction (EIB) after the exercise period, as measured by FEV1 [1 s forced expiratory volume], FEF25-75% [forced expiratory fraction from 25-75% vital capacity], .ovrhdot.Vmax 70% [maximal expiratory flow at 70% total lung capacity] TLC and specific airway conductance (SGaw). The degree of minute ventilation (.ovrhdot.VE) as measured during exercise with airway anesthesia was significantly decreased (P < 0.01) compared with .ovrhdot.VE measured during exercise without lidocaine. Local anesthesia of the upper and large airways in patients with bronchial asthma may significantly inhibit EIB and significantly decrease .ovrhdot.VE during moderate exercise. Mucosal receptors in the upper and large airways may be directly involved in the initiation of EIB; their stimulation may be responsible for increased ventilation during exercise.