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Correspondence  |   December 2006
What Sunrise Might Reveal
Author Affiliations & Notes
  • Robert Hanss, M.D.
    *
  • *University-Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.
Article Information
Correspondence
Correspondence   |   December 2006
What Sunrise Might Reveal
Anesthesiology 12 2006, Vol.105, 1283. doi:
Anesthesiology 12 2006, Vol.105, 1283. doi:
In Reply:—
We thank Dr. Lacassie for and appreciate his valuable comment on our study.1 We agree with his statement that if prophylactic treatment of postspinal hypotension is based on measurement of heart rate variability (HRV), timing of the analysis is crucial. Measurement of HRV is performed to analyze autonomic nervous system regulation. It was clearly demonstrated by Chassard and Bruguerolle2 as well as Takase et al.  3 that autonomic nervous system activity demonstrates circadian rhythm. Therefore, timing of the measurement is important and should be comparable in all patients. In our previous studies, baseline analysis of HRV on the day of surgery directly before volume preload and regional block was demonstrated to identify patients at risk of hypotension in the course of subarachnoid block,4,5 whereas the analysis on the day before surgery did not correlate with postspinal hypotension.
Events of the current study were defined based on these findings. Baseline analysis identifying patients at risk was the analysis on the day of surgery before volume preload and anesthesia. Because cesarean deliveries were performed at 8:00 am, all analyses were performed at the same time. The measurement on the day before surgery was performed according to our previous studies and confirmed that there was no correlation between HRV parameters at that event and postspinal hypotension. We conclude that HRV changes during a 24-h period. Therefore, under study conditions, analyses should be performed at the same time to secure comparability of results, as was done in our study.
*University-Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.
References
Hanss R, Bein B, Francksen H, Scherkl W, Bauer M, Doerges V, Steinfath M, Scholz J, Tonner PH: Heart rate variability–guided prophylactic treatment of severe hypotension after subarachnoid block for elective cesarean delivery. Anesthesiology 2006; 104:635–43Hanss, R Bein, B Francksen, H Scherkl, W Bauer, M Doerges, V Steinfath, M Scholz, J Tonner, PH
Chassard D, Bruguerolle B: Chronobiology and anesthesia. Anesthesiology 2004; 100:413–27Chassard, D Bruguerolle, B
Takase B, Kitamura H, Noritake M, Nagase T, Kurita A, Ohsuzu F, Matsuoka T: Assessment of diabetic autonomic neuropathy using twenty-four-hour spectral analysis of heart rate variability: A comparison with the findings of the Ewing battery. Jpn Heart J 2002; 43:127–35Takase, B Kitamura, H Noritake, M Nagase, T Kurita, A Ohsuzu, F Matsuoka, T
Hanss R, Bein B, Ledowski T, Lehmkuhl M, Ohnesorge H, Scherkl W, Steinfath M, Scholz J, Tonner PH: Heart rate variability predicts severe hypotension after spinal anesthesia for elective cesarean delivery. Anesthesiology 2005; 102:1086–93Hanss, R Bein, B Ledowski, T Lehmkuhl, M Ohnesorge, H Scherkl, W Steinfath, M Scholz, J Tonner, PH
Hanss R, Bein B, Weseloh H, Bauer M, Cavus E, Steinfath M, Scholz J, Tonner PH: Heart rate variability predicts severe hypotension after spinal anesthesia. Anesthesiology 2006; 104:537–45Hanss, R Bein, B Weseloh, H Bauer, M Cavus, E Steinfath, M Scholz, J Tonner, PH