Study On The Role Of Segmental Bioimpedance Technique In Ultrafiltration Evaluation Of Peritoneal Dialysis

BackgroundThe prevalence of chronic kidney disease(CKD)is gradually increasing worldwide and has become an important public health problem worldwide.End-stage renal disease(ESRD)is a clinically critical condition with many complications and high mortality,and its incidence is increasing year by year,which is a serious threat to life and health.Due to the limited renal sources,the treatment of end-stage renal disease mainly relies on dialysis,including hemodialysis and peritoneal dialysis.Peritoneal dialysis is used as the main treatment for end-stage renal disease due to the advantages of higher early survival rate,protection of residual renal function and low cross-infection rate.In peritoneal dialysis(PD),patients are prone to overhydration problems.overhydration leads to adverse clinical outcomes such as increased hypertension,cardiovascular morbidity and mortality.Overhydration is an independent risk factor for death in patients with end-stage renal disease,so it is critical to monitor the patient’s water load status and thus guide the patient on dialysis.Meeting the patient’s ultrafiltration goals is necessary to maintain normal blood volume in the patient.Currently,ultrafiltration goals cannot be better met because of the inability to know the amount of peritoneal fluid in peritoneal dialysis patients.Clinicians adjust peritoneal dialysis protocols to achieve ultrafiltration goals based on empirical trial-and-error methods;however,this method is uncertain,influenced by clinician experience,and does not allow for real-time quantification of ultrafiltration volumes in peritoneal dialysis patients.Assessment of peritoneal dialysis ultrafiltration volume is therefore important to guide peritoneal dialysis protocols.Bioimpedance analysis(BIA)has been used for many years to measure whole-body fluid volume and can provide information about the state of water load.However,standard BIA has been unable to measure the volume in the peritoneal cavity due to fundamental physical and technical problems.Fansan Zhu et al.proposed continuous quantitative measurement of peritoneal fluid dissolution using the segmental bioelectrical impedance(SBIA)technique.ObjectiveStudy on the applicability of Segbioimpedance technique in ultrafiltration evaluation of peritoneal dialysis patients.Materials and Method1 ParticipantsPatients were admitted to the Department of Nephrology of the First Affiliated Hospital of Zhengzhou University from 2020.6.15 to 2020.12.15 for routine PET examinations.Inclusion criteria:age≥18 years,≤80 years;duration of peritoneal dialysis≥1 month;clinically stable,no acute medical problems within the previous 3 months;study approved by the ethics committee and signed informed consent form.Exclusion criteria:acute medical problems within the previous 3 months;concurrent participation in another clinical study(except observational trials);psychological conditions that could interfere with patient compliance or understanding of the study protocol;pregnancy;limb amputation;pacemaker and implantable pump installation;human immunodeficiency virus(HIV)infection;failure to sign an informed consent form.2 PETPatients on abdominal dialysis were evacuated of abdominal fluid in the morning and 2.5%glucose concentration of peritoneal dialysis fluid 2L was instilled into the abdomen.Serum and dialysate levels were measured at 0,120,and 240 minutes after perfusion of peritoneal dialysate,respectively.According to the creatinine dialysate/plasma ratio(D/P)Twardowski grouping criteria:D/Pcr=0.34-0.49 for low transit,D/Pcr 0.50-0.65 for low mean transit,D/Pcr 0.66-0.81 for high mean transit,and D/Pcr 0.82-1.03 for high transit,respectively,at 0,120 The levels of dialysate and serum creatinine were measured by drawing 10 ml each of serum and dialysate at 0,120,240 min after perfusion of peritoneal dialysate,respectively.After 10 ml of abdominal dialysis fluid was withdrawn at 240 min,the abdominal fluid was emptied and weighed.The difference between the weight of the infused and drawn dialysate was used to calculate the ultrafiltration volume(UFVMEA).It was assumed that the density of both fluids was 1 kg/L,so 1 kg=1 L.3 BIA measurementsBioimpedance measurements were performed using a German Fersen body composition analyzer with four sensing electrodes placed under the patient’s tenth rib(S1,S2)and hip(S3,S4),with a continuous injection of alternating current(5 kHz,0.05-0.7 mA)during the measurement.The injected current penetrated the peritoneal cavity on both sides of the body.The segmental resistance at 5 kHz(R5,in Ω)was measured from the multifrequency data.BIA measurements were started 5 to 10 minutes after the patient entered the supine position,and after 5 minutes of baseline BIA measurements,the peritoneal cavity was filled with dialysis fluid,BIA measurements were continued at 10-minute intervals over a 4-hour period and ended when dialysis fluid drainage was completed,and 4-hour real-time IPVSBIA was calculated.Clinical information was also collected from the patient,including sex,age,dialysis age,height,weight,and BMI,systolic and diastolic blood pressure,heart rate,serum urea nitrogen,creatinine and so on.Statistical methods:The statistical software SPSS25.0 was used to deal with the data,and the Graphpad Prism8.0 software was used to draw charts.The measurement data in accordance with the normal distribution are expressed by the mean ±standard deviation(X±S),the quantitative data are compared by t-test,and the measurement data that do not conform to the normal distribution are expressed by quartile spacing.Pearson correlation analysis and Bland-Altman consistency test were used to compare the correlation and consistency between the measured values of 4 h ultrafiltration(SBIA)and the measured values.P<0.05 indicates that the difference is statistically significant.Results1.A total of 30 patients were included.9 patients dropped out of the study due to subjective factors in the measurement process,technical operation problems and other reasons,and 21 patients are in the study.The average resistance RE of 21 patients was 30.83±7.69Ω on fasting and 27.55±6.57 Ω after abdominal cavity was filled with liquid.The resistance difference between fasting resistance and abdominal cavity filled with fluid was 2.71± 1.13 Ω,and the resistance was significantly decreased after abdominal cavity was filled with fluid(t=11.01,P<0.01).The resistance of 21 patients with fasting and abdominal cavity filled with fluid was 30.83 ±7.69Ω and 27.55±6.57 Ω,respectively.The average value of Vf was 2L,the average Ls of the distance from the electrode piece to the buttock electrode piece under the tenth rib was 36.55 ±3.30cm,and the average calibration parameter Ks was 10.56 ±3.09cm.2.The correlation coefficient between UFVSBIA and weighing measurement UFVMEA R2=0.21,p<0.05,which suggests that there is a correlation between them.Bland-Altman analysis showed that the bias of UFVSBIA for PD actual UF volume was 0.12L,with a 95%concordant limit of-0.5 to 0.74L.It can be concluded that the UFVSBIA measured by electrical impedance method and UFVMEA measured by weighing method are in good agreement.3.The average maximum UFVSBIA was 1.16±0.60L,which was 0.72±0.49L(95%CI:0.41-1.02)higher than that of UFVSBIA at the end of stay and 0.84 ±0.64L(95%CI:0.55-1.12)higher than that of UFVMEA at the end of stay.The maximum UFVSBIA time was 108±68min.Conclusion1.Segment Bioimpedance technique can be used to monitor the volume change of peritoneal fluid during dialysis in peritoneal dialysis patients.2.Segmental Bioimpedance technique can be used to assess dialysis ultrafiltration volume in peritoneal dialysis patients and guide the adjustment of peritoneal dialysis protocols.