In Vivo Monitoring Of Tracheal Intubation Based On Optical Fiber Sensing

Respiratory diseases are one of the most common and most lethal diseases in human beings,and endotracheal intubation plays a crucial role as the first step of emergency treatment and surgery for respiratory diseases.If the cuff pressure after endotracheal intubation is improper or the airway resistance is too large,it will cause irreversible damage to the patient's respiratory system.Using the optical fiber F-P sensor for in vivo monitoring,the pressure of the cuff and airway resistance in the patient can be obtained,the sensitivity and accuracy of detection can be improved,and the patient's respiratory system and life can be protected.At the same time,it is of great significance to fill the gap of in vivo monitoring of clinical mechanical ventilation,reduce the sequela of intubation and reduce the monitoring cost.In this paper,with endotracheal intubation as the research background,one of the methods for the treatment of respiratory diseases,based on the optical fiber Fabry-Perot(F-P)sensor,to carry out the research on the monitoring of internal pressure in patients with endotracheal intubation,The research status of cuff pressure,respiratory resistance monitoring and optical fiber F-P sensor in endotracheal intubation were introduced.The microcavity and thin film optical fiber F-P sensors used in endotracheal intubation were designed to monitor the cuff pressure and airway resistance in patients respectively.The principle of bending and pressure detection by the sensor is studied,and the relationship between the sensor and spectrum is analyzed theoretically.Then,the characteristics of human respiratory system and Weibel lung anatomical model are introduced.The contact force of cuff,clamp force and airflow force of endotracheal intubation are analyzed and studied,and the safe range of relevant mechanical characteristics is obtained.The structure of the sensor was optimized by COMSOL,and the feasibility of the sensor was verified.For the microcavity sensor,the bending sensitivity of the encapsulated fiber is 14.3?m/N,the optimal inner diameter of the encapsulated fiber is 2000?m,and the attenuation of the optical intensity at 10° is about 10%.For the thin film sensor,the best film thickness is 10?m,and the best film material is aluminum.The microcavity fiber F-P sensor was fabricated by hydrofluoric acid etching,and the thin film fiber F-P sensor was fabricated by assembly.Finally,the experiments show that the sensitivity of the micro-cavity fiber F-P sensor is 99mW/kPa and 50mW/kPa respectively in the inflating and deflating state of the cuff,and it can judge the contact state between the cuff and the gas pipe wall.The temperature experiment proves that the sensor has a good ability to resist temperature interference.The thin-film optical fiber F-P sensor has a pressure sensitivity of 1.96 pM/Pa in the pressure range of 0?1kPa,and has good linearity and repeatability.The two fiber optic F-P sensors studied in this paper have the characteristics of high sensitivity,low cost and anti-temperature interference,which can provide effective reference for monitoring the airbag pressure and airway resistance in endotracheal intubation.