Protective Effect of Etomidate on Kainic Acid-induced Neurotoxicity in Rat Hippocampus / 대한마취과학회지

BACKGROUND: The present investigation was undertaken to evaluate the neuroprotective effect of etomidate against kainic acid (KA) induced neurotoxicity in rats by using the immunoreactivity of heat shock protein-70 (HSP-70) and the acid-fuchsin stain. METHODS: Administration of etomidate (20 mg/kg, I.P.) was performed in sequence; first being just one hour after a KA (10 mg/kg, I.P.) injection, then three more times at one hour intervals. Neuronal damages in the hippocampus were evaluated by using the acid-fuchsin stain to detect cell death and HSP-70 induction as an index of cell injury at 24 h after the administration of KA. RESULTS: HSP-70 induction and acid fuchsin positive neurons were increased in the CA1 and CA3 regions of the hippocampus after a KA injection but significantly decreased by an injection of etomidate (P < 0.01). CONCLUSIONS: These results suggest that the etomidate has a potential effect on the protection of neurons against KA-induced neurotoxicity.

Research on Etomidate Complications Observed during Induction / 대한마취과학회지

BACKGROUND: The properties of etomidate include hemodynamic stability, minimal respiratory depression, cerebral protection, and rapid recovery. However, its drawbacks include temporary inhibition of steroid synthesis, pain on injection, thrombophlebitis, myoclonus, nausea and vomiting. This study was done to discover the incidence of complications which could be observed during induction and the relationship between these complications and the age, sex and weight of Koreans. METHODS: Induction was done by etomidate 0.3 mg/kg and vecuronium 0.1 mg/kg. Pain on injection and hiccup were checked as present or absent. Myoclonus was checked as absent, mild, or severe. RESULTS: The incidence of pain on injection, hiccup and myoclonus were 4%, 10%, and 40% (mild 28%, severe 12%) respectively. There was no association between pain on injection and hiccup or myoclonus. Hiccup and myoclonus had some association (Gamma 0.774). Logistic regression revealed that there was no association between pain on injection or hiccup, and sex, age or weight. Myoclonus had some association with age and weight. The occurrence of myoclonus could be estimated by the following equation. log[ Fj(x) / { 1 Fj(x) } ] = aj 0.061 age 0.019 weight j = 1, 2 As age or weight increased, the myoclonus was more likely to fall at the low end (i.e., absence). CONCLUSIONS: The incidences of the pain on injection, hiccup and myoclonus were 4%, 10% and 40% respectively. The hiccup and the myoclonus had some positive association. The occurrence of myoclonus decreased as age or weight increased.

Correlations among Bispectral Index, Observer's Assessment of Alertness/sedation (OAA/S) Scale and Blood Concentration during Anesthesia Induction with Etomidate / 대한마취과학회지

BACKGROUND: Etomidate is a rapid-acting sedative/hypnotic agent with little or no cardiovascular effect and a high therapeutic index. For this reason, etomidate has been used as an anesthetic induction and maintenance agent in patients with poor cardiovascular reserve. Bispectral index (BIS), a parameter derived from electroencephalography (EEG), has been proposed as a measure of anesthetic effect and is shown to correlate with increasing sedation and loss of consciousness. To establish its utility for this purpose, it is important to determine the correlation among BIS, measured drug concentration, and increasing levels of sedation. This study was designed to evaluate this relation for etomidate. METHODS: Eighteen adult patients scheduled for elective surgery, ASA physical status I or II, were included. Etomidate was administerd until loss of consciousness (loss of verbal contact) using syringe pump with a constant rate (150 ml/h) and patients were observed until regaining consciousness as decided by prompt verbal response on command of "open your eyes". A BIS was monitored, arterial blood samples were obtained for analysis of drug concentration, and the patients were evaluated for level of sedation by the responsiveness portion of the modified observer's assessment of alertness/sedation (OAA/S) scale. RESULTS: The BIS (r = 0.86) correlated significantly with the OAA/S more than the etomidate plasma concentration (r = 0.57). The BIS values, OAA/S, and blood concentrations were 50, 1.26, and 1337 ng/ml at induction and 75, 4.6, and 236 ng/ml at awakening, respectively. CONCLUSIONS: We concluded that the BIS accurately predicted level of sedation with etomidate during anesthesia induction, but the correlation between blood concentration and level of sedation was less strong.

Midazolam/Sufentanil vs Etomidate/Sufentanil for the Induction of Anesthesia in Patients with Cardiac Disease / 대한마취과학회지

BACKGROUND: Induction of general anesthesia in patients with cardiac disease must guarantee hemodynamic stability and should result in a satisfactory anesthetic level. The purpose of this study was to analyze the hemodynamic effects of midazolam/sufentanil in comparison with etomidate/sufentanil used for induction of anesthesia in patients with cardiac disease. METHODS: All the patients (n = 30) in the study were about to undergo cardiac surgery and were divided into the midazolam group (n = 15) and etomidate group (n = 15). The induction dose of midazolam was 0.18 mg/kg, etomidate 0.3 mg/kg, vecuronium 0.15 mg/kg, sufentanil 3 microgram/kg, hemodynamics and oxygenation were recorded in the awake state (pre-induction), and 10 minutes after intubation (post-intubation). RESULTS: The etomidate group had a shorter time of anesthetic induction, and some myoclonic movement (13%) was observed. After intubation, reductions of heart rate (13.8%), mean arterial pressure (18.4%), cardiac index (14.8%), left ventricular stroke work index (9.7 - 38.5%), oxygen delivery index (7.43%), oxygen consumption index (10.3%), and Qs/Qt (25.6%), and an increase in central venous pressure (0 - 50%) were observed in both groups. Decreases in right ventricular stroke work index and mean arterial pressure were observed in the midazolam group, but no change in right ventricular stroke work index and a decrease in mean arterial pressure was observed in the etomidate group. In the midazolam group the values of right ventricular stroke work index and mean arterial pressure were significantly lower than in the etomidate group. The heart rate of the midazolam group in patients with CABG were significantly lower than in the etomidate group. CONCLUSIONS: The results of this study shows that etomidate was found to be as reliable and effective an agent for induction as midazolam.

Determinants of Effective Dose of Thiopental Sodium, Propofol and Etomidate in Elderly / 대한마취과학회지

BACKGROUND: Many drugs are commonly administered according to total body weight or age basis. However, drugs are primarily distributed to the lean body mass. This study was undertaken to find out the best determinant for drug requirements during induction in elderly. METHODS: Forty-five ASA 1 to 3 male and female patients older than 65 years scheduled for elective surgery were divided into 3 groups and received thiopental sodium 62.5 mg/min (group T, n = 15), propofol 25 mg/min (group P, n = 15), or etomidate 5 mg/min (group E, n = 15) respectively. Kendall's tau test for correlations was used to describe the relationship between drug requirements for induction and total body weight, lean body mass determined by Weisburg's modification of Gubner's formula, ideal body weight calculated by Devine's method, and body surface area. RESULTS: Loss of consciousness was obtained with a thiopental sodium dose of 128.4 +/- 29.3 mg, propofol 59.8 +/- 13.6 mg, and etomidate 9.8 +/- 1.4 mg. Kendall's tau correlation test showed that requirements of drugs were related to lean body mass (group T, r = 0.490*, group P, r = 0.433*, group E, r = 0.493*, global P < 0.05) and ideal body weight (group P, r = 0.426*, group E, r = 0.434*, p < 0.05), but not to total body weight or body surface area. CONCLUSIONS: Our results indicate that drug requirements for induction of anesthesia correlate better with lean body mass and ideal body weight than with total body weight or body surface area in elderly patients.

The Effects of Etomidate on the Isolated Porcine Coronary Artery / 대한마취과학회지

BACKGROUND: Etomidate produces minimal cardiovascular effects in clinical uses but their effects on the porcine coronary arteries are not well known yet. We studied the direct effects of etomidate on porcine coronary arterial tone and the underlying mechanism of its vascular relaxation. METHODS: Porcine coronary arterial ring segments (3-4 mm) with or without endothelium were suspended in modified Krebs solution (37oC) and preconstricted with K+ 40 mM. Changes in tension were measured following cumulative administrations of etomidate (10(-5), 5 x 10(-5) and 10(-4) M). Relaxation caused by etomidate (10(-4)M) were measured in the presence of either NG-nitro-L-arginine methyl ether (L-NAME 10(-5)M, n = 13), indomethacin (2.8 x 10(-5)M, n = 12), methylene blue (2 x 10(-5)M, n = 12), tetraethylammonium (TEA, KCa2+ blocker, 20 mM, n = 11), glibenclamide (n = 13) 2.5 x 10(-5)M or 4-aminopyridine (4-AP, K+ DR blocker, 10 4 M, n = 12). Effects of etomidate on Ca2+ influx through the voltage operated channel (VOC) of the vascular cells were also evaluated. RESULTS: Arterial reings were relaxed by etomidate in a concentration-dependent manner and these effects were not affected by endothelium. In the etomidate pretreated group, arterial ring in a calcium-free solution showed no contraction with KCl 40 mM, but the contraction after the administration of calcium 2.5 mM less than without etomidate group (47.2 +/- 8.7% vs 97.7 +/- 10.6%). The other group, not pretreated with etomidate, showed the same vascular tone of the control group in a slow upstroke manner with calcium administration. Pretreatment with either L-NAME, indomethacin and methylene blue did not affect etomidate-induced vasorelaxation. The TEA, glibenclamide and 4-AP pretreated groups also did not affect the vascular relaxation. CONCLUSIONS: Etomidate relaxes the porcine coronary artery in a concentration-dependent manner withor without endothelium, via inhibition of Ca2+ influx through the voltage-operated Ca2+ channel.

Effects of Etomidate, Propofol and Thiopental Sodium on Intraocular Pressure during the Induction of Anesthesia / 대한마취과학회지

BACKGROUND: During ophthalmologic surgery, a variety of anesthetic induction techniques are used in an attempt to prevent the rise of intraocular pressure (IOP). This study compared the effects of etomidate, a new intravenous anesthetic agent, on the changes in IOP with those of thiopental sodium and propofol. METHODS: Forty-five patients were randomly allocated and divided into three groups to be injected intravenously with etomidate 0.2-0.3 mg/kg (E-group, n = 15), propofol 2-3 mg/kg (P-group, n = 15) or thiopental sodium 4-5 mg/kg (T-group, n = 15). Systolic arterial pressure (SAP), heart rate (HR) and intraocular pressure (IOP) were measured at 1, 2 and 3 minutes after the administration of the induction agents. During the induction of anesthesia, the incidence of IV injection pain, myoclonus, hiccup and a decrease in SAP of more than 30% were investigated. RESULTS: At 1, 2 and 3 min following the induction of anesthesia, the SAP in the P-Group decreased significantly more than that in the other two groups (P < 0.05). After the induction, heart rate in the T-Group increased significantly more than that in the other two groups (P < 0.05). The three intravenous agents induced a significant decrease in IOP after an injection (P < 0.05). Comparing the three groups, the IOP in the E- and P-Group decreased significantly more than that in the T-Group (P < 0.05). CONCLUSIONS: Etomidate may be used as a choice of intravenous induction agent to reduce intraocular pressure in ophthalmologic operations especially in an emergency situation, geriatric and hypovolemic patients.

The Effect of Thiopental Sodium, Etomidate and Propofol on Systemic Vascular Resistance and Venous Capacitance during Cardiopulmonary Bypass / 대한마취과학회지

BACKGROUND: The focus of this study is the effects of thiopental sodium, etomidate and propofol on systemic vascular resistance and venous capacitance during cardiopulmonary bypass with constant pump flow. METHODS: Thirty patients (ASA III) scheduled for open heart surgery were randomly divided into three groups. Anesthesia was induced with thiopental sodium 5 mg/kg, fentanyl 5 microgram/kg and vecuronium 1 mg/kg. CPB was conduced with a membrane oxygenator using non-pulsatile flow and moderate hypothermia. When rectal temperature and pump flow had been stable for 5 min, patients randomly received thiopental sodium 4 mg/kg, etomidate 0.3 mg/kg and propofol 2 mg/kg. Perfusion pressure and pump flow were measured 0, 1, 3, 5, 10, 15, 20 and 30 min after administration. RESULTS: The systemic vascular resistance index (SVRI) decreased to 84.3% of the control values after thiopental sodium 4 mg/kg, to 74.7% of the control after etomidate 0.3 mg/kg and to 79.8% of the control after propofol 2 mg/kg. SVRI returned to control value levels 3 min after the administration of thiopental sodium, 20 min after etomidate, and 5 min after propofol. Thiopental sodium, etomidate and propofol reduced venous reservoir volume 1 min after injection and the reduction was sustained throughout the all period of the cardiopulmonary bypass. CONCLUSIONS: The results indicate that thiopental sodium, etomidate and propofol dilate both resistance and capacitance vessels, but there was no correlation between the two vessels.

The Comparison of the Effects of Propofol and Etomidate on Seizure Duration and Hemodynamic Responses during ECT / 대한마취과학회지

BACKGROUND: The clinical efficacy of electroconvulsive therapy (ECT) primarily depends on the adequacy of the seizure duration, but the intravenous anesthetics which are commonly used for ECT may possess anticonvulsant properties and shorten the seizure duration. The aim of this study was to compare the effects of propofol and etomidate on seizure duration and hemodynamic responses during ECT. METHODS: 30 patients undergoing maintenance ECTs were evaluated and divided into two groups randomly. Hypnosis was induced with a bolus injection of either 1.5 mg/kg of propofol or 0.3 mg/kg of etomidate in each group. Time to unconsciousness, seizure duration, heart rate, mean arterial pressure and recovery time were measured after delivery of electrical stimulus. The dynamic energy (joules) delivered was recorded. Correlation between seizure duration and recovery time was calculated and the rates of seizure induction failure after first electrical stimulus were compared. RESULTS: The seizure duration was shorter in the propofol group (34.0 +/- 3.8 s) than in the etomidate group (50.0 +/- 4.0 s)(P < 0.01). The heart rate was significantly lower in the propofol group (132.1 +/- 3.8, 99.7 +/- 6.2 bpm) than in the etomidate group (146.0 +/- 4.2, 119.8 +/- 7.5 bpm) at the time of ECT and 1 min after ECT respectively (P < 0.05). The mean arterial pressure was significantly lower in the propofol group than in the etomidate group from the time of ECT to 10 min after ECT (P < 0.05). CONCLUSIONS: Propofol showed excellent hemodynamic stability and was a good hypnotic for ECT therapy, but etomidate might be a useful alternative to propofol in patients who have an inadequate seizure duration.

Induction with Intravenous 0.3 mg/kg Etomidate Maintains Venous Capacitance of Normovolemic Rat / 대한마취과학회지

BACKGROUND: Etomidate is short-acting non-barbiturate intravenous anesthetic with minimal cardiovascular depression. As a small change in venous capacitance significantly alters venous return and thus cardiac output, it is important to know the effects of intravenous anesthetics on venous capacitance. The purpose of this study was to examine the effect of etomidate or pentobarbital (control agent) on venous capacitance. METHOD: All twenty rats (etomidate group: 10, pentobarbital group: 10), weighing 350-450 gram, were anesthetized with pentobarbital 50 mg/kg given intraperitoneally for surgical preparation. Mean arterial pressure (MAP), heart rate (HR), and mean circulatory filling pressure (MCFP) were measured in the awake state(recovered from pentobarbital anesthesia for surgical preparation) as well as during anesthesia with etomidate or pentobarbital. Venous capacitance was assessed before and during anesthesia with etomidate or pentobarbital by measuring MCFP. MCFP was measured during a brief period of circulatory arrest produced by inflating a balloon inserted in right atrium. RESULTS: As compared with MCFP in the corresponding awake state, MCFP was not significantly altered by etomidate but significantly decreased by pentobarbital. As compared with MAP in the corresponding awake state, MAP was not significantly altered by etomidate but significantly decreased by pentobarbital. CONCLUSION: The results suggest that unaltered venous capacitance by etomidate may contribute to a maintained MAP but increased venous capacitance by pentobarbital decrease in MAP of the normovolemic rat.