The Study Of Application Of Noninvasive Hemodynamic Monitoring In Order To Assess The Dry Weight Of Patients Taking Maintenance Hemodialysis

Objective: By studying the dependency of the thoracic fluid content, measured by noninvasive hemodynamic monitor, and two indicators, i.e. the percentage of total body water in the body weight, TBW%, and the percentage of extracellular water in the total body water, ECW/TBW%, measured by Maltron BioScan 916 bioelectricity impedance instrument, trying to find out whether TFC could represent the capacity state of MHD patients and, furthermore, to discuss its clinical value in assessing dry weight.①透龄≥3个月;②每周透析2～3次,每次4～4.5小时;③超滤量/体重%<5%;④血白蛋白≥35g/L;⑤临床评估法评价达干体重;⑥尿量<400ml/d;⑦BMI在18.5～23.9kg/m2之间;⑧体内无金属支架或起搏器;⑨自愿参加本研究。Methods: 1 Grouping: The subjects are divided into two groups: the control group and the case group. The control group: 200 healthy volunteers, 100 males and 100 femals, selected among the staff and their relatives and relatives of patients in our hospital. Exclusion criteria:①Body mass index (BMI) <18.5kg/m2 or >23.9kg/m2;②Heart failure;③hepatic cirrhosis;④chronic kidney disease;⑤Hypertension;⑥Malignant tumor (Cancer). The case group: the patients of end stage renal disease, taking hemodialysis in the Blood Purification Center of 4th Hospital of Hebei Medical University. Inclusion criteria:①Time since had hemodialysis≥3 months;②Taking Hemodialysis 2~4 times a week, 4~4.5 hours each time;③Ultrafiltration/weight%<5%;④Albumin≥35g/L;⑤dry weight standards (as estimated by clinical assessment)reached after each session;⑥urine volume<400ml/L;⑦BMI ranges from 18.5 to 23.9 kg/m2;⑧No metal stents or pacemaker in vivo;⑨Volunteer in this study. There are 42 subjects complied these criteria, 25 males and 17 females, among which are 20 patients having protopathy of chronic glomerulonephritis, 4 patients of hypertensive nephropathy, 3 patients of diabetic nephropathy, 3 patients of ADPKD, 2 patients of Alport syndrome, 1 patients of AASV, 1 patients of lupus nephritis,1 patients of Aristolochic acid nephropathy, and 7 patients of unknown causes. During hemodialysis, each patient took supine position all the time, with strict restriction from infusion, transfusion of blood or blood products, and having no drinking. There is no ultrafiltration curve or adjustable sodium in the sessions. The contents of Dialysate include Na+ of 140mmol/L,K+ of 2.0~3.0mmol/L and Ca+ of 1.25～1.5mmol/L.And the bicarbonate dialysate is always used during the research, with temperature ranges from 36 to 36.5℃, the flow rate of blood ranges from 200 to 270 mL/min.The case group is further grouped into three subgroup: the subgroup of being very close to the dry weight standards (A subgroup), the subgroup of having exceeded the dry weight standards (B subgroup) and the subgroup of not having reached the dry weight standards (C subgroup), based on the comparison of TBW% and ECW/TBW% of patients after hemodialysis with the healthy people (defined by the conclusion of the research in our center as such: TBW%:male 60.53±4.98,female 59.07±6.73;ECW/TBW%:male 42.23±4.81,female 41.00±3.08). The dry weight of patients in B subgroup is amended downwards and the dry weight of patients in C subgroup upwards, then analyzed again by Maltron BioScan 916 bioelectricity impedance instrument, resulting in reaching the dry weight standards; the patients in such procedure are set as correction group (D group).2 Procedures:①TFC of 200 subjects in the control group when quietly taking supine position is measured by noninvasive hemodynamic monitor(BioZ; Cardio Dynamics;U.S).②Then we measured TFC of 42 subjects in the case group before and after the hemodialysis session; And simultaneously we measured TBW% and ECW/TBW% by Maltron BioScan 916 bioelectricity impedance instrument.③The hemodynamic changing of patients is continuously monitored during the hemodialysis session, with one group of data recorded per 30 minutes. And observing the change trend of TFC and other parameters, the variation quantity is calculated. Adjusting the Ultrafiltration at the right time.④Calculating TFC variation(△TFC=TFCafter-TFCbefore).⑤The change of symptom and sign of patients during adjusting their dry weight is recorded.3 SPSS13.0 software is adopted to conduct Statistical analysis on the recorded data, with numerous data given as means±SD. Inter-group difference is tested by independent t-test. Linear regression analysis and its correlated analysis are conducted between TFC andTBW%, between TFC and ECW/TBW% and between△TFC and ultrafiltration; P<0.05 is considered statistically significant.Results: 1 TFC and TBW% of 17 female patients in the case group are positive correlated with Pearson correlation coefficient r=0.762,P=0.000;TFC and ECW/TBW% positive correlated with Pearson correlation coefficient r=0.714,P=0.000.TFC and TBW% of 25 male patients in the case group are positive correlated with Pearson correlation coefficient r=0.705,P=0.000; TFC and ECW/TBW% positive correlated with Pearson correlation coefficient r=0.603,P=0.000.2 The difference between TFC of patients, 17 females (31.80±4.21 vs. 25.61±1.95,P<0.05) and 25 males (36.07±4.85 vs. 29.91±2.05,P<0.05) in the case group, before Hemodialysis session and TFC of healthy people in control group is statistically significant; TFC of patients in case group is higher than it of people in control group. Moreover, with the increase of ultrafiltration, TFC drops gradually, having linear trend.△TFC and ultrafiltration are negative correlated with Pearson correlation coefficient r=-0.699,P=0.000. The regression equation of ultrafiltration and△TFC is UF=1.545-0.223×△T FC.3 The comparison of the three subgroup and the correction subgroup of case group with the control group:①The discrepancy of males in A subgroup (30.64±2.72 vs. 29.91±2.05,P>0.05) from subjects in control group and of females in A subgroup (26.82±2.51 vs. 25.61±1.95,P>0.05) from subjects in control group are statistically insignificant;②The discrepancy of males in B subgroup (32.55±3.72 vs. 29.91±2.05,P<0.05) from subjects in control group and discrepancy of females in B subgroup (29.50±1.50 vs. 25.61±1.95,P<0.05) from subjects in control group are statistically significant; TFC of patients in B subgroup is higher than TFC of healthy people in the control group;③The discrepancy of males in C subgroup (26.32±2.39 vs. 29.91±2.05,P<0.05) from subjects in control group and discrepancy of females in C subgroup (23.73±1.87 vs. 25.61±1.95,P<0.05) from subjects in control group are statistically significant; TFC of patients in C subgroup is lower than TFC of healthy people in the control group. The discrepancy of males in D group (30.51±2.54 vs. 29.91±2.05,P>0.05) from subjects in control group and of females in D group (25.96±2.13 vs. 25.61±1.95,P>0.05) from subjects in control group are statistically insignificant.4 The declines of dry weight of patients in B subgroup range from 0.4 to 1.2 kg, with average value of 0.78 kg. The raises of dry weight of patients in C subgroup range from 0.4 to 2.5 kg, with average value of 1.36 kg. During the declines of dry weight, the controls of blood pressure of some of the patients are relatively more ideal, with decrease of ingestion of oral antihypertensive drugs. During the raises of dry weight, some of the patients feel more comfortable, with relatively lower possibilities that blood pressure drops or muscle spasm happens when taking hemodialysis.Conclusion: 1 TFC, measured by BioZ.com noninvasive hemodynamic monitor, could represent the overall capacity states of MHD patients. With the gradually increase of UF, TFC has a decline trend. There is averagely 220 mL dehydration per unit of TFC decrease. TFC is a relatively sensitive indicator representing the capacity change of MHD patients.2 TFC, measured by BioZ.com noninvasive hemodynamic monitor, could be used to assess the dry weight of MHD patients. When TFC of patients after Hemodialysis reaches the normal level of healthy people (mean±SD):males (27.86～31.96) kOhm-1, females (23.66～27.56) kOhm-1, it is reasonable to take them as reached the dry weight standards.3 The accuracy of the application of BioZ.com noninvasive hemodynamic monitor to measure TFC in order to assess the dry weight of MHD patients is even better than it of clinic assessment methods.4 Referencing the parameters of Hemodynamics can avoid or reduce blood pressure drops or muscle spasm happens when taking hemodialysis.