The role of blood volume reduction in the genesis of intradialytic hypotension.
BACKGROUND
The aim of this multicenter prospective study was to investigate the role of relative blood volume (RBV) reduction on intradialytic hypotension.


METHODS
One hundred twenty-three patients on chronic hemodialysis therapy were considered a priori normotensive (reference group A), intradialytic hypotension prone (group B), and hypertensive (group C). RBV was continuously monitored, and diastolic and systolic blood pressure (SBP) and heart rate (HR) were measured at 20-minute intervals during three dialysis sessions.


RESULTS
Intradialytic RBV reduction was -13.8% +/- 7.0% and similar in the three groups (P = 0.841). SBP and RBV decreased during dialysis, with a sharp initial decrease (in the first 20 minutes for SBP and the first 40 minutes for RBV), followed by a slower decrease. The lying bradycardic response before dialysis was less in group B than group A (a decrease of 3 +/- 7 versus 9 +/- 9 beats/min; P < 0.001). When symptomatic hypotension occurred, RBV reduction was not significantly different from that recorded at the same time during hypotension-free sessions (-13.9% +/- 6.4% versus -12.7% +/- 5.2%; P = 0.149). Group, baseline plasma-dialysate sodium gradient, RBV line irregularity, and early RBV and HR reduction during dialysis influenced the relative risk for symptomatic hypotension with a sensitivity of 80% versus 30% for RBV alone.


CONCLUSIONS
We found no difference in reduction in RBV in the three groups and no critical RBV level for the appearance of symptomatic hypotension. With variables easily available within 40 minutes of dialysis, RBV monitoring increases the prediction of symptomatic hypotension.
Andrulli
Simeone
S
Department of Nephrology and Dialysis, Azienda Ospedaliera A. Manzoni, Lecco, Italy. s.andrulli@ospedale.lecco.it
Colzani
Sara
S
Mascia
Franco
F
Lucchi
Leonardo
L
Stipo
Lucia
L
Bigi
Maria Carla
MC
Crepaldi
Monica
M
Redaelli
Bruno
B
Albertazzi
Alberto
A
Locatelli
Francesco
F
D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D001810:Blood Volume / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D006973:Hypertension / Q000503:physiopathology; D007022:Hypotension / Q000209:etiology* / Q000503:physiopathology; D007676:Kidney Failure, Chronic / Q000503:physiopathology / Q000628:therapy; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D015999:Multivariate Analysis; D011446:Prospective Studies; D006435:Renal Dialysis / Q000379:methods*