1. Introduction Measuring the cardiac index using ultrasound dilution during hemodialysis (HD) can be used to detect patients with an excessive access flow as well as cardiac impairments. Conclusion The proportion of patients with reduced CI, increased relative access flow and drop in CI during HD is high and can be validly recorded using hemodynamic monitoring. Methods In a prospective cross-sectional study we measured cardiac output (CO), cardiac index (CI) and access flow (AF) at the start and end of a HD session in a large cohort of n=185 stable HD patients using the Transonic HD03 monitor and correlated the results with clinical parameters and bioimpedance measurements (BCM, Fresenius). Table 1: Patient characteristics of the cohort Table 2: Multivariable linear regression model for predicting CI drop. Independent predictors were high age and high UF. An increased access flow, an increased OH and increased peripheral resistance proved to be protective. Fig. 7 and 8: Course of hemodynamic parameters At the end of HD the CI and SCI fell while the AF remained constant. The peripheral resistance and heart rate did not change causing systolic blood pressure to fall. Linear regression model with Delta CI in % of the baseline value as Y adjusted r²=0.36, n=184 variablestandardized betap age- 0.21380.0020 gender 0.002970.6503 overhydration (OH) according to BCM 0.2889<0.0001 ultrafiltration (UF)- 0.4360<0.0001 peripheral resistance at start 0.4126<0.0008 access flow at start 0.21080.0031 systolic BP at start- 0.11070.1055 diastolic BP at start- 0.10380.1904 heart rate at start- 0.0330.5984 CI at start- 0.19250.1266 Patients includedn=185 Age (median)75 (inter-quartile range 65-80) years Gender ratio35 % female, 65 % male Primary renal disease22 % diabetic nephropathy, 18 % glomerulonephritis, 5 % polycystic kidneys, 6 % hypertensive nephropathy, 49 % unknown Cardiac comorbidity46 % valvular disease, 41 % left ventricle hypertrophy,36 % coronary heart disease, 25 % PTCA, 23 % pulmonary hypertension, 8% pacemaker, 20% left ventricular dysfunction Dialysis access84 % native AV fistula, 16 % PTFE shunt Time on dialysis50 (13 - 90) months Dialysis type69 % hemodiafiltration, 31% hemodialysis Residual urine output / 24h0.225 (0-1.2) Liter / 47 % anuria Inter-dialytic weight gain1.76 (0.9 – 2.3) kg / dialysis Dialysis membrane98 % high flux, 2 % low flux Kt/V1.3 (1.3 – 1.7) Dialysis duration4 hours (4;4.25) Blood pump speed300 (280; 320) ml/min Results Measurement of Cardiac Index in Hemodialysis Patients and Predictors for a drop during Hemodialysis Stefanie Haag 1, Björn Friedrich 2, Nils Heyne 1, Ferruh Artunc 1 1 Department of Internal medicine, Division of nephrology, University hospital Tuebingen, Germany 2 Nephrological center Leonberg, Germany. Fig. 1: Distribution of cardiac index (CI) Fig. 2: Distribution of access flow (AF) Fig. 3: Distribution of systemic CI Fig. 4: Correlation of AF with CI Fig. 5: Correlation of AF with SCI Fig. 6: Distribution of the AF/CO ratio 0 % 11 % 14 % 23 % 19 % 17 % 11 % 4 % 1 % 01020304050 l / min / m² l / min l / min / m² 2.76 0.98 2.20 22 2.61 *** CI SCI AF l / min / m² (CI & SCI) or l / min (AF) 2.88 2.27 0.98 0.99 0 1 2 3 4 Start HDFinal HD 2.05 *** 1 % 2 % 10 % 15 % 23 % 18 % 14 % 8 % 5 % 2 % 1 % 2 % -60-40-200204060 drop, % of baseline CI -10 % 134 126 *** 67 66 62 17.217.4 0 20 40 60 80 100 120 140 160 Start HDFinal HD Syst. BP heart rate Dias. BP PR mm Hg (BD) or /min (pulse) or mm Hg/l /min (PR) Fig. 9/10: Distribution of CI drop and correlation of CI fall with drop in syst. BP For 28 % of the patients the CI fell by more than 20 % and was associated with a drop in systolic blood pressure of more than 9 mmHg. Still, CI fall had only a weak correlation to the drop in systolic BP. In 7% of the patients, CI was elevated over 4 L/min/m² whereas 9% had low CI. The CI corrected for AF (= systemic CI) was reduced in 31% of the patients. AF and CI have a strong correlation, whereby SCI no longer correlates with AF, i.e. the AF increases the CI in the HD patients. 17 % of the patients had an increased relative AF exceeding 30 %. Elevated AF >1.75 l/min was found in 24 % of the patients whereas 10% had low AF.