Inhalational conscious sedation with nitrous oxide enhances the cardiac parasympathetic component of heart rate variability.
OBJECTIVE
We investigated the effects of conscious sedation by 30% nitrous oxide inhalation on the cardiac autonomic nervous system in the absence or presence of music listening.


METHODS
The power spectral analysis of heart rate variability (HRV) and cardiovascular parameters were measured in 26 healthy volunteers, who were divided into the control and N(2)O groups.


RESULTS
Nitrous oxide inhalation attenuated the increase in relative low frequency (LF) power in the control group, but relative high frequency (HF) power remained constant compared to a decreased value in the control group. Nitrous oxide inhibited the increase in the LF/HF ratio. These autonomic balance shifts were observed without hemodynamic changes. Additional music during sedation did not alter HRV variables.


CONCLUSIONS
Inhalational sedation with nitrous oxide shifted cardiac sympathetic-parasympathetic balance toward a parasympathetic dominance via the suppression of sympathetic activity. Music listening during sedation did not provide further relaxing effects.
Okushima
Koki
K
Department of Dental Anesthesiology, Kagoshima University Medical and Dental Hospital, Kagoshima, Japan.
Kohjitani
Atsushi
A
Asano
Yoko
Y
Sugiyama
Kazuna
K
D000328:Adult; D000766:Anesthesia, Dental / Q000379:methods*; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D016292:Procedural Sedation / Q000379:methods*; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008297:Male; D009146:Music; D009609:Nitrous Oxide / Q000494:pharmacology*; D010275:Parasympathetic Nervous System / Q000187:drug effects
D018685:Anesthetics, Inhalation; D009609:Nitrous Oxide