Role of tube size and intranasal compression of the nasotracheal tube in respiratory pressure loss during nasotracheal intubation: a laboratory study

BMC Anesthesiology

Research Article

Yoshihiro Takasugi¹  Takahiko Okuda²  Koichi Futagawa²  Satoshi Morishita³  Takeharu Kobayashi³ 

[1] Department of Anesthesiology, Kindai University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-sayama, 589-8511, Osaka, Japan;Department of Anesthesiology, Nara Hospital, Kindai University Faculty of Medicine, 1248-1 Otodacho, Ikoma, 630-0293, Nara, Japan;Product Development Research Center, Daiken Medical Co. Ltd., 2-6-2, Ayumino, Izumi-city, 594-1157, Osaka, Japan;

关键词: Endotracheal tube;    Pressure loss;    Slip joint;    Turbulent flow;    Nasotracheal intubation;   

DOI  :  10.1186/s12871-017-0432-1

 received in 2016-09-06, accepted in 2017-10-03,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundSmall nasotracheal tubes (NTTs) and intranasal compression of the NTT in the nasal cavity may contribute to increasing airway resistance. Since the effects of size, shape, and partial compression of the NTT on airway resistance have not been investigated, values of airway resistance with partial compression of preformed NTTs of various sizes were determined.MethodsTo determine the factors affecting the respiratory pressure loss during the nasotracheal intubation, physical and fluid dynamics simulations were used. The internal minor axes of NTTs in the nasal cavity of intubated patients were measured using dial calipers. In physical and fluid dynamics simulations, pressure losses through the tubular parts, compressed parts, and slip joints of NTTs with internal diameters (IDs) of 6.0, 6.5, 7.0, 7.5, and 8.0 mm were estimated under partial compression.ResultsThe median internal minor axes of the 7.0- and 7.5-mm ID NTTs in the nasal cavity were 5.2 (4.3–5.6) mm and 6.0 (4.2–7.0) mm, respectively. With a volumetric air flow rate of 30 L/min, pressure losses through uncompressed NTTs with IDs of 6.0-, 6.5-, 7.0-, 7.5- and 8.0-mm were 651.6 ± 5.7 (6.64 ± 0.06), 453.4 ± 3.9 (4.62 ± 0.04), 336.5 ± 2.2 (3.43 ± 0.02), 225.2 ± 0.2 (2.30 ± 0.00), and 179.0 ± 1.1 Pa (1.82 ± 0.01 cmH2O), respectively; the pressure losses through the slip joints were 220.3 (2.25), 131.1 (1.33), 86.8 (0.88), 57.1 (0.58), and 36.1 Pa (0.37 cmH2O), respectively; and the pressure losses through the curvature of the NTT were 71.6 (0.73), 69.0 (0.70), 64.8 (0.66), 32.5 (0.33), and 41.6 Pa (0.42 cmH2O), respectively. A maximum compression force of 34.1 N increased the pressure losses by 82.0 (0.84), 38.0 (0.39), 23.5 (0.24), 16.6 (0.17), and 9.3 Pa (0.09 cmH2O), respectively.ConclusionPressure losses through NTTs are in inverse proportion to the tubes’ IDs; greater pressure losses due to slip joints, acute bending, and partial compression of the NTT were obvious in small NTTs. Pressure losses through NTTs, especially in small NTTs, could increase the work of breathing to a greater extent than that through standard tubes; intranasal compression further increases the pressure loss.

【 授权许可】

CC BY   
© The Author(s). 2017