[Assessment of the autonomic nervous activities under nitrous oxide-enflurane anesthesia by heart rate fluctuation analysis].
For numerical expression of the autonomic nervous activities during 60% nitrous oxide (N2O), enflurane (Enf) and oxygen anesthesia, heart rate fluctuations were studied in 13 female patients undergoing a laparoscopic examination. Atropine (0.5 mg im) and hydroxidine (50 mg im) were given one hour prior to induction of anesthesia with thiamylal (5 mg.kg-1 iv). Following the induction, succinylcholine (1 mg.kg-1 iv) was administered, and the trachea was intubated. Enf concentration was monitored throughout the study and expressed by the end-tidal values. An electrocardiogram in lead 2 was recorded on a magnetic tape for 3 minutes each time, before the induction of anesthesia (baseline value), during anesthesia with both 1.9% Enf and 1.0% Enf, then 5 and 20 min after tracheal extubation. These data were subjected later to computer analysis for heart rate fluctuations. At 1.9% Enf and after the skin incision, the R-R intervals and the coefficient variation of R-R interval (CV-RR) were significantly reduced to 90% (P less than 0.05) and 32% (P less than 0.01) of the baseline values respectively. A significant reduction (P less than 0.01) was also observed in both the high frequency component (HFC: 0.15-0.4 Hz) and the low frequency component (LFC: 0.05-0.15 Hz) of the power spectrum of heart rate fluctuations. The peak amplitude and the band area of the HFC were reduced to 20 and 35% of the baseline values, while those of the LFC was reduced to around 14%.(ABSTRACT TRUNCATED AT 250 WORDS)
Shimoda
O
O
Surgical Center, Kumamoto University Hospital.
Kano
T
T
Ii
C
C
Morioka
T
T
Kushiyama
S
S
D000328:Adult; D000769:Anesthesia, Inhalation; D001341:Autonomic Nervous System / Q000502:physiology*; D004737:Enflurane; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D010535:Laparoscopy; D009609:Nitrous Oxide
D004737:Enflurane; D009609:Nitrous Oxide