C. Widmark et al., SPECTRAL-ANALYSIS OF HEART-RATE-VARIABILITY DURING DESFLURANE AND ISOFLURANE ANESTHESIA IN PATIENTS UNDERGOING ARTHROSCOPY, Acta anaesthesiologica Scandinavica, 42(2), 1998, pp. 204-210
Background: We studied the effect of desflurane (DES) and isoflurane (
ISO) on heart rate variability (HRV) using power spectral analysis (PS
A) of PR-interval in 30 patients undergoing arthroscopy, prior to indu
ction, during anaesthesia and up to 3 h of recovery. PSA can distingui
sh low-frequency (LF) component and respiratory sinus arrhythmia (RSA)
that are known to reflect predominantly sympathetic and parasympathet
ic activity, respectively. Methods: After premedication with diclofena
c and midazolam the anaesthesia was induced with propofol and maintain
ed during spontaneous ventilation with either DES or ISO added to a mi
xture of nitrous oxide and oxygen. ECG and transthoracic impedance res
pirometer data were recorded. Power spectra were calculated with an au
toregressive modelling method. Results: Total power (P-TOT) and indivi
dual power in two frequency bands of the HRV spectrum (P-LF, 0.05-0.15
Hz and P-RSA) decreased after induction of anaesthesia in both groups
. At 60, 120 and 180 min of recovery the P-TOT was back to control-val
ue in the DES group but remained reduced in the ISO group. Calculated
as normalised units, the P-LF (nP(LF)) predominated over the P-RSA (nP
(RSA)) during control situations and during recovery. The reverse was
the case during maintenance of anaesthesia. Thirty minutes after induc
tion and during surgical stress the ISO group showed higher heart rate
compared to the DES group as well as compared to control. Conclusion:
DES and ISO produced similar alterations in studied parameters during
the maintenance of anaesthesia. The differences observed between the
groups during recovery may indicate an early intact neural reflex cont
rol system among the subjects exposed to DES. These results suggest th
at DES and ISO reduce the total autonomic neural system activity and a
lter the balance between sympathetic and parasympathetic activities in
a comparable way during maintenance of anaesthesia. A more rapid reco
very phase among the subjects exposed to DES is linked to differences
in pharmacokinetic properties of the inhalation agents.