Study On Wearable In-situ Monitoring Method Of Key Physiological Parameters Of Hemorrhagic Shock Patients

Hemorrhagic shock is the main cause of traumatic death,and the fatality rate is more than 90%.Physiological parameters,such as heart rate,blood pressure,blood oxygen saturation and body temperature,reflecting the changes in human hemodynamics,are important indicators for the diagnosis of hemorrhagic shock.In massive casualty events,the large-scale medical equipment cannot be timely transported to the scene,which result in great difficulty to obtain the vital information of the wounded in-situ.The rescuers have to rely on manual experience to judge the injury.Wearable medical monitoring devices can make up for this deficiency.The existing wearable physiological parameter detection devices,such as electronic wristband,have the poor measurement accuracy beyond medical level.Therefore,constructing a high-precision monitoring model algorithm to realize in-situ monitoring of physiological parameters,such as heart rate,blood pressure,blood oxygen saturation and body temperature,and providing data for injury diagnosis of hemorrhagic shock casualties hold important significance.The research work of this paper mainly includes the following contents:(1)The practicality of photoplethysmography-based heart rate monitoring is investigated.The heart rate monitoring model is constructed by extracting the periodic properties of the photoplethysmography signal in order to achieve in-situ recording of heart rate index.The accuracy of heart rate can reach 93%in laboratory conditions and 91.71%in clinical tests.(2)The physiological importance of important photoplethysmography characteristic factors is investigated,and its temporal and amplitude characteristics are extracted.The blood pressure monitoring model is built using the multiple linear regression method.The effects of various measuring postures on monitoring accuracy and stability are investigated.The validation experiment with 12 patients revealed that 95.65%and 96.38%of the measured samples of systolic and diastolic blood pressure were within the confidence interval,indicating that the monitoring findings were in good agreement with the clinical monitor monitoring data.(3)The blood oxygen saturation monitoring model is built using Lambert-Beer optical law and the difference in light absorption between oxygenated and non-oxygenated hemoglobin.A self-calibration module is intended to eliminate noise-induced unintended errors in blood oxygen saturation measurement.The measured and reference values of blood oxygen saturation show good following properties in the breath-holding experiment.The measurement accuracy in the clinical experiment was found to be 87.23%.(4)The method of single-heat-flux has been enhanced.The ambient temperature is added as a characteristic parameter,and the core temperature monitoring model is built using the ambient temperature and core temperature correlation.According to the results of a body temperature experiment,accuracy can reach 91.67%.The revised method greatly improves the accuracy of body temperature measurement as compared to the previous single-heat-flux method.