Cuffless Continuous Blood Pressure Monitoring Method During The Evacuation Of The Wounded

In everyday life,people bleed due to car accidents,earthquakes or other accidents.During the transfer of the wounded,massive bleeding would not be detected in time,leading to hemorrhagic shock and life threatening.Because blood pressure could not be continuously monitored,the best time for treatment was missed.On the one hand,it is impossible to carry out invasive continuous blood pressure monitoring in transit due to the limitation of environmental conditions and actual conditions in the transit process.On the other hand,current cuff blood pressure monitoring methods cannot continuously monitor blood pressure.Therefore,continuous blood pressure monitoring and timely intervention are of great significance.Based on the non-invasive continuous blood pressure measurement method of sleeveless band based on pulse wave conduction time,blood pressure can be effectively predicted for a single individual within a period of time,and there is great individual difference for different individuals.In the condition of blood loss,the prediction effect of pulse wave conduction time method on blood pressure has not been well established.Therefore,pulse wave conduction time method has not been widely used in clinical medicine and surgery.To solve the above problems,this paper proposes a sleeveless continuous blood pressure measurement method based on PWTT,PPG,HR and HRV.On the basis of PWTT method,PPG characteristic parameters,HR and HRV were added to compensate for the influence of individual differences and changes in blood volume on blood pressure monitoring methods.Under the condition of blood loss,the blood volume in blood vessels changes,and PPG can reflect the influence of blood volume change on it.Loss of blood can lead to biological neuromodulation,leading to changes in heart rate and heart rate variability.Two blood pressure prediction models of blood loss and drug intervention were established by partial least square method.In this paper,animal pig experiments simulating blood loss state and drug intervention state were carried out,and a total of 8 pigs were carried out.Due to the different parts of PPG signal collection,it was found that the PPG signal collected at the snout of the pig was the most optimal.A total of 5 pigs were collected in this part.The model of blood loss yielded 1229 samples.The drug intervention model yielded 1635 samples.Two blood pressure prediction models of blood loss and drug intervention were established by partial least square method,namely the RR interval-hrv model obtained in this paper.In the RR interval-hrv-pwtt model of blood loss and drug intervention,the SBP correlation coefficient r was 0.9192 and 0.8754,respectively.The correlation coefficient r of SBP was 0.7731 and 0.6840,respectively,for common blood loss and drug intervention models.In the model of blood loss at RR interval and drug intervention,the correlation coefficient r of SBP was 0.8943 and 0.8772,respectively.The correlation coefficient r of SBP between HRV blood loss and drug intervention model was 0.9169 and 0.6983,respectively.The correlation of RR interval-hrv-pwtt blood loss was increased by 18.9%,2.8%and 0.2%,respectively,compared with the other three models.The r correlation of RR interval-hrv-pwtt model was increased by 28.0%,-0.2%and 25.4%,respectively,compared with the other three models.Therefore,the blood pressure prediction model established by these characteristic parameters has a significant correlation with invasive blood pressure.It can be used to monitor hemorrhagic shock and blood loss in advance and provide theoretical basis and technical guidance for continuous blood pressure monitoring under the condition of blood loss.