The Study Of Application Of Heart Rate Characteristics In Early Diagnosis Of Late-onset Sepsis In Premature Infants

1.Background and Objection1.1 BackgroundPremature infants have a great risk of septicemia due to the immaturity of their immune system,organs and functions,with a mortality rate of nearly 20%,and there are more likely to have severe permanent neurologic impairment.Among neonates with high-risk factors hospitalized in the Neonatal Intensive Care Unit(NICU),late-onset sepsis(LOS)is one of the major threats of their health.Therefore,early detection of sepsis and treatment,is conducive to reducing mortality and improve prognosis.However,the current clinical laboratory tests existing many limitations,such as the inaccuracy of the diagnostic sensitivity and specificity,and the lag of diagnosis.Heart rate variability(HRV)is the degree of fluctuation of sinus rhythm.Studies abroad have shown that abnormal heart rate characteristics(HRC)with reduced HRV and a short deceleration of heart rate can occur in 12-24h before premature onset of septicemia in premature infants.1.2 ObjectionIn this study,we analyzed the characteristics of Electrocardiogram waveform read from the Electrocardiogram monitor by computer,and research the heart rate characteristic and transcutaneous oxygen saturation(SPO2),perfusion index(PI)during the process of LOS and treatment respectively in infants with septicemia,at the same time compared with non-suspected infants.Evaluating whether the HRC and SP02,PI in infants with septicemia specificity,and assess whether early warning of septicemia is possible and guide clinical treatment.2.Materials and Method2.1 Research objectSelect preterm infants(gestational age<37 weeks)who were born in our hospital from May 2016 to May 2017 and were hospitalized to NICU.Sample exclusion criteria:patients who are allergic to blood pressure cuff,blood oxygen finger or electrocardiogram,or are not suitable for monitoring related parameters because of surface skin damage;patients with congenital heart disease and other heart development problems,patients with arrhythmias;patients with severe postnatal sleep;Patients confirmed by head color Doppler ultrasound with ?-? grade intracranial hemorrhage.123preterm infants enrolled in this study were divided into two groups:septicemia group and non-septicemia group.Data screening criteria:1.effective data for ECG,SPO2,and PI data;2.eliminate the serious noise interference data:QRS wave detection and classification based on the Mindray ECG algorithm,and identification of abnormal cardiac contractions,ventricular flutter and ventricular fibrillation,as well as noise interference data Segment,retain only data segments containing normal QRS waves;3.remove too much data from invalid data segments:each 4096 effective RR interval data segment(about 20-30 minutes)is not more than 45 minutes long.4.data segment is at least 12 hours,and the case data of suspected septicaemia is more than 42 hours(includes Data before and after the diagnosis).5.the data of each case within 7 days of admission were excluded.There were 11 infants in the septicemia group and 54 in the non-septicemia group in accordance with the data screening criteria.2.2 MethodsWe extract RR interval data from electrocardiogram monitoring utilizingcomputer analysis.Then calculating the standard deviation(std),Sample Entropy(SampEn)and Asymmetry(Asym)of RR interval and SPO2,PI to study the characteristics of septicemia and the cure stage respectively,while compare with non-septicemia group.3.Result3.1 The differences of mean value of HRC and SPO2 and PI in septicemia group and non-septicemia group were different:There was no significant difference between two groups of Rri Asym,Rri Std,Rri SampEn,SPO2 in the first second days of diagnosis,first days before diagnosis,first days after diagnosis,and second days after diagnosis(P>0.05).In septicemia group,the mean value of PI was significantly different from that of non-septicaemia group in second days before the diagnosis.There was no more significant difference in mean value of PI(P>0.05)(Table 7).3.2 In septicemia group,the differences in HRC index,SPO2 and PI before and after sepsis:?There were 3 typical cases in 11 showed abnormal HRC in 24 hours before diagnosis:The decrease of heart rate variability(HRV),accompanied with brief decelerations,and the asymmetry of RR interval.? Closer to the diagnosis,the trend of Rri Asym enlargement is obvious.The phenomenon of Rri Asym enlargement can first appear before diagnosis 30h and gradually decrease after diagnosis;Rri Std and PI may be lower than non septicaemia group at 42 hours before diagnosis and gradually increase after diagnosis;Rri SampEn is gradually decreasing before diagnosis and gradually rising after diagnosis;SPO2 has a brief decline before diagnosis.However,there was no significant difference in sepsis group(P>0.05).4.ConclusionIn this study,only preliminary estimates of septicemia can be made due to the limited sample size of septicemia cases at the present stage.This method may have reference value for the early prediction of delayed sepsis in premature infants.However,it is not clearly different from non-septicemia cases.Therefore,the effectiveness of this method for the early prediction of delayed septicemia in premature infants needs further research and verification.