Paralysis of the recurrent nerve is one of the causes of upper airway obstruction and is an unrecognized cause of respiratory failure.
Therefore, in this study, we examined 20 patients with recurrent nerve paralysis and 20 healthy subjects using simple spirometry and usual flow-volume curve inorder to estimate the value of pulmonary funcion test and investigate the effects of upper airway obstrucion to respiratory system. For this purpose, pulmonary funcion tests were done during both expiration and inspiration.
The following results were obtained:
(1) The measurements of spirometry and flow-volume curve during forced inspiration were very useful to detect the abnormality of patients with upper airway obstruction due to recurrent nerve paralysis.
(2) Most of the patients showed “FEV1.0%>FIV1.0%” and “FEV0.5%>FIV0.5%”. “FEV0.5%>FIV0.5%” is very significant to detect the abnormality of the upper airway.
(3) The reduction of the MMIF/MMEF is a little diagnostic value of the upper airway obstruction.
(4) The flow-volume curve was markedly abnormal in most of the patients. The characteristic abnormalities were the reduction of peak expiratory flow and the markedly reduced, constant inspiratory flow.
(5) The values of respiratory resistance were high in all patients, but the absolute value of respiratory resistance was not useful to investigate the characteristics of the abnormality in lung-thorax system due to the upper airway obstruction. To analyze respiratory impairment due to upper airway obstruction, we would say that it is necessary to measure and analyze effective compliance on the forced oscillation method.
