Abstract: FR-PO793

Intradialytic Systolic Blood Pressure and Hemodynamics Are Predominantly Controlled by Baroreflex Mechanisms

Session Information

Category: Dialysis

  • 601 Standard Hemodialysis for ESRD

Authors

  • Rubinger, Dvora, Hadassah University Medical Center, Jerusalem, Israel
  • Dranitzki Elhalel, Michal, Hadassah University Medical Center, Jerusalem, Israel
  • Sapoznikov, Dan, Hadassah University Medical Center, Jerusalem, Israel
Background

Systolic blood pressure (SBP) is believed to be controlled by both baroreflex (BARO) and non-baroreflex (NON-BARO) sympathetically mediated central mechanisms.

Methods

To assess the relative contribution of these mechanisms during hemodialysis (HD), beat-to-beat SBP and interbeat interval (IBI) monitoring using Finometer device was performed during a 4 hr regular HD session in 51 non-diabetic patients, age 52±16 y. BARO and NON-BARO activity episodes were evaluated by the calculation of the slope of between IBI and SBP in 1 min sequences; a positive correlation coefficient (r>0.5) was considered to be representative of BARO activity, whereas a negative correlation was considered to represent NON-BARO sympathetic activity. LFα coefficient, a measure of predominantly BARO function was calculated as the square root of the ratio between average IBI power and average SBP power in the low frequency band (0.04-0.15 Hz). Cardiac output (CO), stroke volume (SV) and total peripheral resistance (TPR) were calculated using the Modelflow simulation method.

Results

The averaged variables for the 1st and the 4th HD hr (median and interquartile range) are shown in Table 1.(see table below)
During HD, LFα increased from 3.76 (2.34) in the 1st to 4.17 (3.37) the last hr (p=0.013).

Conclusion

Our data show: 1. At the begining of HD, SBP is dually controlled by both BARO and NON-BARO mechanisms. 2. During ultrafiltration, the maintenance of constant SBP is achieved by predominant BARO activation. 3. The decrease in CO and SV during ultafiltration is compensated by an increase in TPR. The intradialytic hemodynamic stability seems to be dependent on the adequacy and the strength of the BARO response.

Table 1.
 HD 1st hrHD 4th hrp
SBP (mmHg)133 (22)131 (26)NS
IBI (ms)805 (129)796 (183)NS
% BARO episodes62(61)96 (67)0.003
% NON-BARO episodes38 (61)4 (67)0.003
CO (L/min)6.78 (2.10)5.64 (2.58)0.001
SV (ml)89 (28)73 (38)0.001
TPR (mmHg.s/ml)0.875 (0.310)1.009 (0.530)0.001