Changes in heart rate variability during anaesthesia induction using sevoflurane or isoflurane with nitrous oxide.
BACKGROUND
The purpose of this study was to compare cardiac sympathetic and parasympathetic balance using heart rate variability (HRV) during induction of anaesthesia between sevoflurane and isoflurane in combination with nitrous oxide.


METHODS
40 individuals aged from 30 to 60 years, scheduled for general anaesthesia were equally divided into sevoflurane or isoflurane groups. After 100% oxygen inhalation for a few minutes, anaesthesia was induced with nitrous oxide 3 L min-1, oxygen 3 L min-1 and sevoflurane or isoflurane. Sevoflurane or isoflurane concentration was increased by 0.5% every 2 to 3 breaths until 5% was attained for sevoflurane, or 3% for isoflurane. Vecuronium was administered to facilitate tracheal intubation. After intubation, sevoflurane was set to 2% while isoflurane was set to 1% with nitrous oxide with oxygen (1:1) for 5 min.


RESULTS
Both sevoflurane and isoflurane provoked a decrease in blood pressure, total power, the low frequency component (LF), and high frequency component (HF) of HRV. Although the heart rate increased during isoflurane anaesthesia, it decreased under sevoflurane. The power of LF and HF also decreased in both groups. LF was higher in the isoflurane group while HF was higher in the sevoflurane group. The LF/HF ratio increased transiently in the isoflurane group, but decreased in the sevoflurane group.


CONCLUSION
Anaesthesia induction with isoflurane-nitrous oxide transiently increased cardiac sympathetic activity, while sevoflurane-nitrous oxide decreased both cardiac sympathetic and parasympathetic activities. The balance of cardiac parasympathetic/sympathetic activity was higher in sevoflurane anaesthesia.
['Nishiyama|Tomoki|T|']
D000328:Adult D000769:Anesthesia, Inhalation D018685:Anesthetics, Inhalation D005260:Female D006321:Heart D006339:Heart Rate D006801:Humans D007442:Intubation, Intratracheal D007530:Isoflurane D008297:Male D008738:Methyl Ethers D008875:Middle Aged D016343:Monitoring, Intraoperative D003473:Neuromuscular Nondepolarizing Agents D009609:Nitrous Oxide D010275:Parasympathetic Nervous System D000077149:Sevoflurane D013564:Sympathetic Nervous System D014673:Vecuronium Bromide
heart rate variability induction sevoflurane isoflurane general anaesthesia autonomic nervous system volatile volatile anaesthetics