Journal of anesthesia
-
Journal of anesthesia · Sep 1995
Spontaneous respiration should be avoided in frequency domain analysis of heart rate variability.
To determine whether spontaneous respiration is suitable for frequency domain analysis of heart rate (R-R interval) variability, we studied 15 volunteers (5 men and 10 women, aged 22-34 years) and evaluated the reproducibility of the power spectrum. Electrocardiograms were recorded for 5 min each with spontaneous and rate-controlled respiration (15 breaths·min-1), repeating the same protocol 1 week later. Fast Fourier transformation was performed using the digitized data of the R-R intervals. ⋯ Data were comparable for rate-controlled respiration. Since respiratory parameters strongly influenced the low- and the high-frequency R-R interval power spectra, spontaneous respiration should be avoided. A constant respiratory condition is required to interpret results of frequency domain analysis of R-R interval variability.
-
The effects of propofol on the tone of guinea pig respiratory smooth muscle was studied both in vitro and in vivo. In vitro, the activity of propofol on tracheal smooth muscle was investigated using a force displacement transducer for isometric tension responses. Isoproterenol was used as the control. ⋯ Propofol (1-4.5 mg·kg-1, i.v.) exhibited neither relaxant nor constrictor effects. It is possible that the effects of propofol observed in vitro are due to nonspecific action, while the finding of no effect in vivo could be due to different tissue sensitivity to propofol, i.e., tracheal smooth muscle may be more responsive than bronchial smooth muscle. Propofol does not seem to have any deleterious effects on airway smooth muscle.
-
Journal of anesthesia · Sep 1995
Effects of total intravenous anesthesia with propofol on immuno-endocrine changes during surgical stress.
Endocrine factors and cytokines are crucial to host responses to stress and infection. Because surgery is a major stressful condition, it is necessary to understand the influence of specific anesthetic procedures on immune-endocrine responses. The purpose of this study was to compare total intravenous anesthesia with propofol with conventional inhalational anesthesia on circulating cortisol, adrenocorticotropic hormone (ACTH), prolactin, alpha-melanocyte-stimulating hormone (αMSH), and the cytokine, interleukin-6 (IL-6) in healthy patients undergoing tubal ligation. ⋯ Because ACTH responses to surgery were similar in the two groups, the inhibition likely occurred directly on the adrenal glands. This study is the first to report the effects of anesthesia on circulating αMSH, which was decreased significantly after induction with both anesthetic techniques and was still depressed at 90 min in the propofol patients. Other aspects of immune-endocrine responses to surgery were similar irrespective of anesthetic type, which further suggests a specific suppression of adrenal function by propofol.