Abstract
The upper airway controls air inspiration, regulation of ventilatory volume and protection from noxious particles and gases by neural reflex and mucociliary function. The role of the lower airway is to modulate the inspired air-current for even diffusion and the optimal gas-exchange. Respiratory disturbance in the upper airway has manifold influence on sleep, respiro-circulatory and neuro-psychological functions in varying degress depending on the pathogenetic factor, severity and duration. Although the grade of disturbance in nasal breathing is the same, those with nasal sinusitis often have more damage to the lower airway than those without mucosal inflammation. Laryngeal stenoses elevate respiratory resistance and flatten the peak flow at MEFV-curves. Laryngectomized patients show a change in breathing pattern with increased FRC and decreased tidal volume. Postoperative MEFV-curve recordings showed a steep curve with a larger peak flow and downward convexity, compared with preoperative records. While asleep, patients with upper airway obstruction suffer from more severe disturbance of breathing manifested by loud snoring and apneic episodes than while awake. In a severely obstructed case, the airway is occluded and ventilation stops (sleep apnea). Enforcement of respiratory work and arousal reaction enable overcome the occlusion resulting in breathing, accompanied with snoring. Heavy respiratory intrathoracic pressure-change causes uneven ventilation, pulmonary overload, hypertension, sleep disturbance, daytime sleepiness and deterioration of social activities. Obesity itself disturbs cardio-respiratory functions by excessive fat deposit in various organs inside. When the upper airway is obstructed, it inflicts an additional heavy load on cardiorespiratory functions, which may develop into the Pickwick syndrome. Infants who have great trouble in nasal breathing can hardly breathe through the mouth, and this creates manifest respiratory disturbance, especially while they sleep. They have less tolerance against such respiratory disturbance. These factors may be one of the causes of sudden infant death syndrome. Properly selected treatment based on precise examination and diagnosis of the location, pathogenesis and severity of obstruction achieves satisfactory results subjectively and objectively.
