EVALUATION OF ACOUSTIC FUNCTION BEFORE AND AFTER ENDOTRACHEAL INTUBATION

• Published in: JIBI INKOKA TEMBO Vol. 37; no. 5; pp. 535 - 544
• Main Authors: Matsui, Masato, Hesaka, Hirohiko, Kamide, Yousuke, Moriyama, Hiroshi, Amaki, Yoshikiyo
• Format: Journal Article
• Language: Japanese
• Published: Society of Oto-rhino-laryngology Tokyo 1994; 耳鼻咽喉科展望会
• Subjects: cough reflex; endotracheal intubation; hoarseness; spontaneous respiration; the time from reversion to extubation
• ISSN: 0386-9687; 1883-6429
• DOI: 10.11453/orltokyo1958.37.535

Some patients may complain of hoarseness on the day after they have had an operationperformed under general anesthesia.The effect of endotracheal intubation on the larynx and trachea were therefore studied.The subjects of this study were 41 patients (30 males and 11 females) who underwent an operation with endotracheal intubation under general anesthesia, and their mean age was 38.2 years. These patients were selected mainly from those in whom neither neck nor chest region was expected to be manipulated in operation. The effects on phonation were analyzed at three different times, the day before operation, the day after operation and one week after operation, with respect to the amplitude perturbation quotient (APQ), pitch perturbation quotient (PPQ), nor-malized noise energy (NNE), pitch, flow and intensity.In addition, maximum phonation time (MPT) was measured, and the flow and intensity therein were also recorded.At the time of the operation, the size of the intubation tube and the intra-cuff pressures upon intubation and extubation were recorded, and radiogram of the cervicothoracic region were taken while the patients were in the state of intubation. The subjects were classified into a hoarseness group and a non-hoarseness group based on the degree of increase in APQ, PPQ and NNE, and the two groups were compared with respect to several parameters.A significant difference (P<0.005) was observed with respect to the time from reversion (injection of an antagonist to muscle-relaxant) to the extubation and the difference in the inner diameter of the trachea in the chest region and that in the neck region. Postoperative hoarseness was thus surmised to be mainly due to temporary chorditis caused by a long-lasting cough reflex beginning from the time of recovery of spontaneous respiration to the time of extubation.Regarding the postoperative speech level, both intensity and flow decreased concurrently in 65% of the subjects, suggesting anesthesia-induced transient functional weakening of the muscles related to breathing, etc.