Effects of pentobarbital and etomidate on plasma catecholamine levels and spectral analysis of blood pressure and heart rate in dogs.
The present paper investigates the effects of two anaesthetic drugs (pentobarbital and etomidate) on both short-term variabilities of systolic blood pressure (SBP) and heart rate (HR) using fast Fourier transformation and catecholamine plasma levels. HR and BP were continuously recorded through an arterial catheter and blood samples were taken from the jugular vein. Spectral analysis was performed first in the conscious state and six minutes after induction of anaesthesia on a series of 256 consecutive BP and HR values (delta t: 2 Hz). The area under the curve (AUC) was determined in the low-frequency component of the SBP (LF: 40-150 mHz), in the high-frequency band of HR (HF: respiratory frequency +/- 50 mHz) and in the total frequency spectra. Results were normalized by calculation of the ratio between AUC of LF and HF and the total AUC of the corresponding spectrum (TS). Etomidate (2 mg/kg i.v.) induced a significant increase in TS and LF without changing the LF/TS ratio or the HR variability when compared with the awake period. Catecholamine plasma levels did not change. In contrast, pentobarbital (30 mg/kg i.v.) decreased the values of LF, HF, LF/TS and HF/TS and catecholamine plasma levels. These results suggest that pentobarbital decreases the activity of the two components of the autonomic nervous system whereas etomidate induces only minimal changes.
Mazerolles
M
M
Laboratoire de Pharmacologie Médicale et Clinique, INSERM U317, Faculté de Médecine, Toulouse, France.
Senard
J M
JM
Verwaerde
P
P
Tran
M A
MA
Montastruc
J L
JL
Virenque
C
C
Montastruc
P
P
D000759:Adjuvants, Anesthesia / Q000494:pharmacology*; D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002395:Catecholamines / Q000097:blood*; D004285:Dogs; D005045:Etomidate / Q000494:pharmacology*; D005583:Fourier Analysis; D006339:Heart Rate / Q000187:drug effects*; D010424:Pentobarbital / Q000494:pharmacology*; D012815:Signal Processing, Computer-Assisted
D000759:Adjuvants, Anesthesia; D018686:Anesthetics, Intravenous; D002395:Catecholamines; D010424:Pentobarbital; D005045:Etomidate