Heart rate variability is an indicator for intradialytic hypotension among chronic hemodialysis patients.
BACKGROUND
Intradialytic hypotension (IDH) carries adverse impact. Heart rate variability (HRV) represents autonomic cardiac regulation which influences intradialytic blood pressure. We aimed to evaluate the association between IDH and HRV.


METHODS
This prospective study was carried out in a teaching hospital in Taiwan from June to August 2010. Adult patients on chronic hemodialysis without active medical conditions were enrolled and received HRV measurements for 4 times (before and during an index hemodialysis session). Patients were categorized by the changes of systolic blood pressure during the index hemodialysis into Group 1 (elevation >20 mmHg), Group 2 (decrease >20 mmHg), and Group 3 (others). Then we compared HRV indices among the three groups, and determined the indicators for IDH.


RESULTS
One hundred and seventy-one patients (96 women, mean age 64.9 years) were enrolled and categorized into Group 1 (n = 47, 27.5 %), Group 2 (n = 45, 26.3 %) and Group 3 (n = 79, 46.2 %). Comparing with Group 1 and/or Group 3, Group 2 had significantly higher blood pressure at hemodialysis initiation (most p < 0.001) and statistically lower levels of HRV indices including variance, total power, very low-frequency, low-frequency and high-frequency since the middle phase of the hemodialysis. By logistic regression method, higher systemic blood pressure [odds ratio (OR) 1.048; p < 0.001], heart rate (OR 1.093; p = 0.021), low-frequency/high-frequency ratio (OR 1.715; p = 0.022), as well as lower variance (OR 0.639; p = 0.048) at hemodialysis initiation were independently associated with intradialytic blood pressure changes.


CONCLUSIONS
HRV is a useful indicator for IDH among hemodialysis patients.
Division of Nephrology, Department of Internal Medicine, Saint Mary's Hospital Luodong, Yilan, Taiwan.
Yu-Ming
YM
Chang
Division of Nephrology, Department of Internal Medicine, Saint Mary's Hospital Luodong, Yilan, Taiwan. chungyy2001@yahoo.com.tw.|Saint Mary's Medicine, Nursing and Management College, Yilan, Taiwan. chungyy2001@yahoo.com.tw.
Chih-Chung
http://orcid.org/0000-0003-2220-7574
CC
Shiao
Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei, Taiwan.
Kuo-Chi
KC
Chang
Department of Nursing, Saint Mary's Hospital Luodong, Yilan, Taiwan.
I-Ling
IL
Chen
Department of Nursing, Saint Mary's Hospital Luodong, Yilan, Taiwan.
Chuan-Lan
CL
Yang
Department of Nursing, Saint Mary's Hospital Luodong, Yilan, Taiwan.
Show-Chin
SC
Leu
Department of Nursing, Saint Mary's Hospital Luodong, Yilan, Taiwan.
Hung-Li
HL
Su
Division of Nephrology, Department of Internal Medicine, Saint Mary's Hospital Luodong, Yilan, Taiwan.
Jsun-Liang
JL
Kao
Division of Nephrology, Department of Internal Medicine, Saint Mary's Hospital Luodong, Yilan, Taiwan.
Shih-Ching
SC
Tsai
Division of Nephrology, Department of Internal Medicine, Saint Mary's Hospital Luodong, Yilan, Taiwan.
Rong-Na
RN
Jhen
D000368:Aged; D005260:Female; D006339:Heart Rate; D006801:Humans; D007022:Hypotension / Q000209:etiology / Q000503:physiopathology*; D007676:Kidney Failure, Chronic / Q000503:physiopathology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D006435:Renal Dialysis / Q000009:adverse effects*
Autonomic nervous system; Heart rate variability; Hemodialysis; Intradialytic hypotension; Sympathetic activity