Ephedrine and phenylephrine are used to treat hypotension during combined general and epidural anesthesia, and they may change anesthetic depth. In the current study, we evaluated the effects of ephedrine versus phenylephrine on bispectral index (BIS) during combined general and epidural anesthesia. After injection of ropivacaine through the epidural catheter, general anesthesia was induced with propofol and vecuronium, and was maintained with 0.75% sevoflurane. Approximately 10 min after the intubation, BIS was recorded as a baseline value. Patients with decreases in arterial blood pressure <30% of the preanesthetic values were defined as control group (n = 9). Patients who had to be treated for larger decreases in arterial blood pressure were randomly assigned to receive ephedrine 0.1 mg/kg (n = 17) or phenylephrine 2 micro g/kg (n = 17). BIS values were recorded at 1-min intervals for 10 min. BIS in the ephedrine group was significantly larger from 7 to 10 min than that in the control and phenylephrine groups (P < 0.05). Seven patients in the ephedrine group had BIS >60, whereas no patient in the control and phenylephrine groups had BIS >60 (P < 0.005). Ephedrine, but not phenylephrine, increased BIS during general anesthesia combined with epidural anesthesia.
The sedative effects of epidural anesthesia without volatile and IV anesthetics and quantification of the degree of epidural anesthesia-induced sedation have not been investigated. In the current study we evaluated the effects of epidural anesthesia on the bispectral index (BIS) during the awake phase and during general anesthesia. After placing the epidural catheter, the patients were randomly allocated to 2 groups receiving either 5 mL of epidural saline (group S) or the same volume of 0.75% ropivacaine (group R). The BIS measurements during the awake phase were performed at 7, 12, 13, 14, 22, and 23 min after the epidural injection. General anesthesia was then induced with propofol and vecuronium and maintained with 0.75% sevoflurane. From approximately 10 min after tracheal intubation, the BIS measurements were made at 1-min intervals for 10 min. The BIS during the awake phase was significantly lower in group R than in group S (P < 0.05). The BIS during general anesthesia was significantly lower in group R than in group S (P < 0.0001). Epidural anesthesia decreased the BIS during the awake phase and during general anesthesia. The decrease of the BIS associated with epidural anesthesia was more prominent during general anesthesia than during the awake phase.
This study was designed to examined the effects of inhalation anaesthetics on function and metabolism in isolated ischaemic rat hearts. Four volatile anaesthetics in two different concentrations (1.0 to 1.5 MAC) were used before whole heart ischaemia was induced for 15 min followed by reperfusion for 30 min. The data were compared with a control group in which inhalation anaesthetics were not used. Before ischaemia, volatile anaesthetics depressed ventricular function. During reperfusion, ventricular function and coronary flow in both halothane groups were significantly lower than those in the control group. Myocardial ATP concentrations in the 1.0 MAC of enflurane and isoflurane groups were significantly higher than those in the control group. We conclude that halothane had more depressant effects than the other anaesthetics and that enflurane and isoflurane may enhance metabolic recovery in the ischaemic working rat heart.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.