Research On Noninvasive Monitoring Of Intracranial Pressure By NIRS And Its Clinical Application

Increased intracranial pressure is widespread in the clinical syndrome of neurosurgery patients,and is a serious threat to the patients' health.At present,there is not any sufficiently safe and effective technology to monitor intracranial pressure at the bedside precisely and non-invasively.In this paper,a study of non-invasive monitoring of intracranial pressure changes caused by brain edema was carried out based on the near infrared technology,due to its safety,high sensitivity and deep penetration in tissues.The main work and innovations of this paper:1.According to different types of brain edema,some simulation models were designed.The Monte Carlo method was carried out on the single brain edema model and the combined one.In the experiments,the relationships were explored between light intensity and brain edema situation.The best detecting range of adult brain by the near infrared technology was determined.2.Some brain phantoms were constructed by gelatin,and the phantom parameters were changed according to the single brain edema simulation models and the voltage on the phantom surface was monitored by the system.It found that the voltage was related with brain edema situation,and the change tendency was similar to the simulation results by Monte Carlo,and the reliability of Monte Carlo simulation models was finally verified.3.The rat brain edema model was established by lipopolysaccharide.The invasive intracranial pressure and reduced scattering coefficient were detected by Codman intracranial pressure monitor and a homemade system,respectively.After analysis,the change tendency of two parameters under brain edema was obtained,and the detection of intracranial pressure was completed by NIRS in rats.4.A mathematical model was established based on the intracranial pressure and reduced scattering coefficient which were collected from postoperative patients in the neurosurgery care unit.The intracranial pressure calibration by NIRS was completed according to the accurate detection of invasive intracranial pressure.It was shown that the changes of intracranial pressure were consistent with the changes of reduced scattering coefficient at 834 nm,which means the changes of intracranial pressure caused by brain edema could be monitored by near infrared light at 834 nm.