The Influence of the Endotracheal Tube on the Vocal Cord by the Change of Head Position

Research Project

Project/Area Number	07672168
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	Surgical dentistry
Research Institution	Osaka University
Principal Investigator	SHIBUTANI Tohru (1996) Osaka Univ.Faculty of Dentistry , Assistant Professor, 歯学部, 講師 (30206148) 堀智範 (1995) 大阪大学, 歯学部, 助手 (80252691)
Co-Investigator(Kenkyū-buntansha)	滋谷徹大阪大学, 歯学部, 講師 (30206148)
Project Period (FY)	1995 – 1996
Project Status	Completed (Fiscal Year 1996)
Budget Amount *help	¥2,100,000 (Direct Cost: ¥2,100,000) Fiscal Year 1996: ¥500,000 (Direct Cost: ¥500,000) Fiscal Year 1995: ¥1,600,000 (Direct Cost: ¥1,600,000)
Keywords	Hed rotation / Vocal cord / Endotracheal tube / MRI / Morphological change / 声門 / 核磁気共鳴像
Research Abstract	We investigated the influence of the endotracheal tube on the vocal cord by head rotation. 1.The airway from the nasal and oral cavity to the trachea was imaged with magnetic resonance imaging (MRI) in two head position ; ordinary head position and head rotation. The life sized airway model was made of acrylic plate based on MR images. Various types and sizes of endotracheal tubes (ETT) were intubated in the model and the pressure between the ETT and the vocal cord was measured with pressure transducer. The ETT was pressed on the opposite side of the vocal cord. The strength of the pressure was varied by the type and size of the ETT. 2.Mongrel dogs were intubated and the ETT was pressed to the larynx with the pressure obtained in the model. The morphological changes of the larynx were observed macroscopically and microscopically with scanning Electron Microscopy. Laryngeal ruber was seen after 6 hours with a pressure of 25 mmHg and after 2 hours of 50mmHg. Microscopical changes such as desquamation of stratified squamous epithelium, partial lack and disarrangement of micriridge, and lack and fusion of cilia, appeared before the macroscopical changes. Consequently, in operation which require head rotation, we have to select sutable ETT and pay attention to prevent postoperative complications such as laryngeal edema and granuloma.