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Changes in heart rate variability may reflect sympatholysis during spinal anaesthesia
Author(s) -
Hanss R.,
Ohnesorge H.,
Kaufmann M.,
Gaupp R.,
Ledowski T.,
Steinfath M.,
Scholz J.,
Bein B.
Publication year - 2007
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/j.1399-6576.2007.01455.x
Subject(s) - medicine , heart failure , heart rate , anesthesia , heart rate variability , blood pressure , cardiology
Background: To investigate if changes in low‐to‐high frequency ratio (LF/HF), low frequency (LF) and high frequency (HF) heart rate variability reflect autonomic regulation during spinal anaesthesia (SA) in pregnant women scheduled for elective Caesarean section. Methods: Prospective clinical trial. Systolic blood pressure (SBP) and heart rate variability were analysed at baseline, 5 min after SA and 15 min after SA. Patients were assigned by baseline LF/HF. Group LF/HF < 2.5 ( n = 52) was compared to group LF/HF > 2.5 ( n = 48). Non‐parametric tests for statistical analysis. Results: Group LF/HF > 2.5 showed a significant decrease in LF/HF and LF as well as an increase in HF during SA (median, range): baseline LF/HF [4.0 (3.2/4.8)] decreased to 2.3 (1.3/3.4) at event 15 min after SA ( P < 0.001). Baseline LF = 59(43/71)% decreased to 40 (27/55)% at event 15 min after SA ( P < 0.05). Baseline HF = 15(13/22)% increased to 26(15/41)% at event 15 min after SA ( P < 0.05). In contrast, group LF/HF < 2.5 demonstrated only moderate changes in LF/HF, LF and HF during SA. SBP decreased significantly in group LF/HF > 2.5 (median and range) lowest SBP group LF/HF > 2.5: 80 (50/127 mmHg vs. group LF/HF < 2.5: 109 (104/142) mmHg, P < 0.001. Decrease of SBP before and after SA was correlated with a decrease in LF/HF, LF, and HF, respectively: LF/HF – SBP: r = 0.30, r 2 = 0.09, P < 0.001; LF – SBP: r = 0.25, r 2 = 0.06, P < 0.05, HF, NS. Conclusions: Changes in heart rate variability parameters in the course of SA may reflect a decrease in sympathetic activity and relative increase in parasympathetic activity as a result of the block. In the course of SA, the more pronounced the changes in heart rate variability were the more distinct the hypotension.