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PubMed1988

Comparative hemodynamic effects of propofol and thiamylal sodium during anesthetic induction for myocardial revascularization.

The safety and efficacy of propofol, a new intravenous anesthetic agent, have been demonstrated in healthy patients. Twenty-one patients, ASA III-IV, undergoing elective myocardial revascularization, were randomly chosen to receive either propofol, 2.5 mg/kg, or thiamylal, 4 mg/kg. for the induction of anesthesia. Hemodynamics were recorded at one and three minutes after drug administration during spontaneous respiration. After the addition of halothane and pancuronium with controlled ventilation, measurements were made immediately prior to and one minute after intubation. Five patients were dropped from the study, four due to airway problems and one due to severe hypotension following an induction dose of propofol. Statistics were done using data from the remaining 16 patients, eight in each group. Administration of propofol resulted in significant decreases in mean arterial pressure (MAP), systemic vascular resistance (SVR), and left ventricular stroke work index (LVSWI); as well as an increase in heart rate (HR). These changes were further accentuated by the addition of halothane and pancuronium prior to intubation. Patients in the thiamylal group experienced no significant hemodynamic changes until halothane and pancuronium were added and controlled ventilation was instituted. With these additions, the thiamylal group showed significant decreases in MAP and LVSWI immediately prior to intubation. Both groups experienced significant increases in HR following intubation, but no evidence of myocardial ischemia was seen in either group. All other parameters returned toward control values. Propofol appeared to be safe and effective for the induction of anesthesia in this group of patients, although its hemodynamic effects were greater than those of thiamylal.

Adult↗

PubMed2005

Efficacy and adverse effects of rectal thiamylal with oral triclofos for children undergoing magnetic resonance imaging.

We studied the efficacy and adverse effects of rectal thiamylal in combination with oral triclofos in sedation for pediatric magnetic resonance imaging. Five hundred forty-six children underwent MRI examination from January of 1997 to December of 2001. Among them, 10mg/kg of rectal thiamylal was administrated after oral triclofos in 378 children. Successful sedation was obtained in 321 of 378 patients (85%) after a single rectal administration of thiamylal. Totally, 369 children (98%) could undergo MRI examination completely under successful sedation. Adverse effect was observed only in one patient showing respiratory depression. Rectal thiamylal is effective for sedation for MRI in children. Adverse effect was rare in our patients. Although the risk of side effect was considered to be rare, we should follow principles for the sedation of children.

Administration, Oral↗

PubMed1987

Follicular fluid concentrations of thiopental and thiamylal during laparoscopy for oocyte retrieval.

Because access into ovarian tissue of drugs used during anesthesia may be potentially harmful to the oocyte and/or follicular structure, we measured concentrations of thiopental (n = 15) and thiamylal (n = 9) in follicular fluid (FF) aspirates of 24 patients who underwent laparoscopic oocyte retrieval. In both groups, measurable amounts of the respective drug were found in all FF aspirates. Within individual patients, plasma concentrations of both drugs declined during the period of sampling between initial and final follicular aspiration. The mean plasma drug concentration was 7.99 +/- 3.97 micrograms/ml in the thiamylal group and 4.13 +/- 0.90 micrograms/ml in the thiopental group. Mean drug concentrations in FF were similar in both groups (thiopental 1.62 +/- 0.61 micrograms/ml; thiamylal 1.67 +/- 0.83 micrograms/ml). The mean FF/plasma concentration ratio during the sampling period was greater in the thiopental group (0.41 +/- 0.19) as compared with the thiamylal group (0.22 +/- 0.14). Several steps in the clinical management of these patients can be taken to reduce exposure of oocytes to drugs used during anesthesia.

Adult↗

PubMed1978

Effect of thiamylal on the sensitivity of glycerinated cardiac fibres to calcium.

Clarification of the mechanisms of the myocardial depression produced by thiamylal was sought by studying the effect of thiamylal upon the sensitivity of contractile proteins to calcium (Ca2+), by using glycerinated muscle fibres from the canine right ventricle. The dose--response relationship between the concentration of Ca2+ and the force of contraction of the glycerinated cardiac muscle fibres was not shifted from the control curve by the administration of thiamylal 67 microgram ml-1. This result suggests that the changes in the sensitivity of contractile proteins to Ca2+ are not responsible for the depression of myocardial performance produced by thiamylal.

Animals↗

PubMedDate not supplied

Report of a fatal thiamylal intoxication.

A fatality due to the intravenous administration of thiamylal is reported. Quantitation of the drug was accomplished by high-performance liquid chromatography (HPLC) and confirmation was by gas chromatography/mass spectrometry (GC/MS). Postmortem tissue concentrations of thiamylal were as follow: 129 mg/L in blood, 366 mg/kg in liver, and 116 mg/kg in brain. Thiamylal was not detected in the urine, gastric contents, or bile. Analytical caveats involving the quantitation of thiamylal are also discussed.

Adult↗

PubMed1991

Thiamylal- and halothane-sparing effect of diazepam in dogs.

The thiamylal- and halothane-sparing effect of diazepam was studied in two experiments using 32 conditioned dogs. Twenty-four dogs received 0.05, 0.1 or 0.2 ml/kg diazepam or 0.9% saline (placebo) prior to the administration of thiamylal sodium i.v. Eight dogs received 0.1 or 0.2 mg/kg diazepam i.v. or placebo prior to or during halothane anesthesia. All three doses of diazepam significantly decreased the amount of thiamylal required to allow orotracheal intubation. The 0.2 mg/kg i.v. dose of diazepam produced the most significant effects. Premedication of dogs with diazepam did not reduce the concentration of halothane required to maintain anesthesia. The administration of 0.1 and 0.2 mg/kg diazepam i.v. during halothane anesthesia decreased the concentration of halothane required to maintain anesthesia. These studies demonstrate that diazepam reduces the amount of thiamylal required for orotracheal intubation, and when given intra-operatively reduces the concentration of halothane required to maintain anesthesia.

Animals↗

PubMed1975

Effects of change in frequency of stimulation on myocardial depression produced by thiamylal and halothane.

The effects of change in the frequency of stimulation on the myocardial contractility depressed by thiamylal and halothane were studied in isolated dog heart muscle. An increase in the frequency of stimulation from 0.1 to 0.6 cps resulted in a progressive in increase in net-shortening (delta1) and maximum velocity of shortening at 0.4 g preload (V'max), namely a positive staircase. The myocardium previously depressed to a similar degree by thiamylal or halothane still showed a positive staircase. This result indicates that the mechanism to produce the myocardial depression by thiamylal or halothane is not a complete inhibition of Ca++ influx across the cell membrane. The time to reach a steady state of contraction following an increase in the frequency of stimulation was longer in the presence than in the absence of these anesthetics. The degree of recovery from the myocardial depression by increasing the frequency of stimulation was much higher in the presence of thiamylal than in the presence of halothane. This fact suggests that the mechanism to produce the myocardial depression may be different in there two anesthetics.

Animals↗

PubMed1976

Effects of change in concentration of calcium on myocardial contractility depressed by thiamylal and halothane.

The effects of change in the concentration of Ca++ on myocardial contractility depressed by thiamylal and halothane were studied in isolated dog heart muscle. The concentration of Ca++ in the bathing medium was increased stepwise from 1.9 to 20.9 mM. An increase in Ca++ concentration resulted in an increase both in net-shortening (delta1) and in maximum velocity of shortening at 0.4 g preload (V'max) which reached the maximum values at 11.4mM of Ca++. A further increase in Ca++ concentration rather decreased delta1 and V'max. The concentration-response relation curves in the presence of thiamylal (3.3 mg%) shifted to the right almost parallel to the control curve, with the peaks at 15.2 mM of Ca++. The result indicates that the depression of myocardial contractility produced by thiamylal is counteracted competitively by Ca++. However, the curves in the presence of halothane (5.0 +/- 0.4 mg%) were kept lower than those of the control, with the peaks at 7.6 mM of Ca++. The result shows that the counteraction of Ca++ to the depression of myocardial contractility was limited in the presence of halothane. A similar tendency was observed in maximum force of isometric contraction (Fm). Moreover, in the presence of halothane, the administration of higher concentrations of Ca++ almost always accompanied "after-contraction". From the result obtained and the literature concerned it was suggested that the mechanism for producing the depression of myocardial contractility might be different between thiamylal and halothane in relation to Ca++ movements at the Ca++ storage sites within the myocardium.

Animals↗

PubMed2001

EEG-bispectral index changes with ketamine versus thiamylal induction of anesthesia.

BACKGROUND: The EEG-Bispectral Index (BIS) is a processed EEG information that has been validated as a means to measure the hypnotic effect of anesthetic drugs. In this study we evaluated the BIS changes in induction of anesthesia with ketamine in comparison with that of thiamylal. METHODS: Forty ASA class I and II adult female patients undergoing elective gynecologic surgeries were enrolled into this randomized, prospective study. No premedication was given to the patient. In each patient EEG was recorded continuously from the frontal electrodes using Aspect A-1050 monitor after his arrival at the operating room. Blood pressure and heart rate were also recorded throughout the surgery. After steady baseline recordings of all necessary parameters having been accomplished Group K patients (n = 20) were given an induction dose of ketamine 1.5 mg/kg i.v., whereas Group T patients (n = 20) received thiamylal 5 mg/kg i.v. When loss of consciousness was ascertained, intubation was performed after administration of succinylcholine 1 mg/kg i.v. and anesthesia was maintained with isoflurane-nitrous oxide-oxygen. Demographics, BIS values, HR, BP were analyzed and compared. RESULTS: The demographics were comparable between the two groups. Both groups showed a mean value of BIS of 96 with comparable BP and HR before induction. After study drug the post-induction BIS for ketamine was 94 as against 51 for thiamylal (P < 0.05), 91 against 43 post-succinylcholine (P < 0.05), 92 against 53 post-intubation (P < 0.05) and 45 against 37 five min after isoflurane. BIS remained below 60 throughout the entire course of anesthesia and returned to above 95 on emergence in both groups. None of the patients reported awareness, recall, delirium or hallucination during anesthesia. CONCLUSIONS: Ketamine-induced dissociative anesthesia produces persistently elevated BIS index which is different from thiamylal and those reported with other conventional anesthetic agents. The established range of BIS index appears not to be applicable in patients under ketamine anesthesia. Monitoring the depth of ketamine anesthesia remains to be a challenging problem.

Adult↗

PubMed2005

[Effects of propofol and thiamylal on nicorandil induced ATP-sensitive potassium channel activities in cultured rat aortic smooth muscle cells].

BACKGROUND: Nicorandil, a hybrid ATP-sensitive potassium (K(ATP)) channel opener and nitrate compound, is used clinically for the treatment of angina pectoris. In the present study, we investigated the effects of propofol and thiamylal on sarcolemmal K(ATP) channels activities induced by nicorandil in cultured rat aortic smooth muscle cells. METHODS: We used inside-out patch clamp configurations to investigate the effects of propofol and thiamylal on nicorandil induced K(ATP) channel activities. RESULTS: K(ATP) channel was not spontaneously activated by patch excision in the absence of intracellular ATP. Application of nicorandil (100 microM) induced a marked activation of KATP channel currents, which was completely blocked by 3 microM glibenclamide, the sulfonylurea that blocks K(ATP) channels. Nicorandil induced KATP channel currents were not significantly inhibited by application of 10 and 100 microM propofol to intracellular surface. However, application of 100 and 300 microM thiamylal to intracellular surface significantly inhibited the nicorandil induced K(ATP) channel currents, with relative channel activities decreasing to 0.65 +/- 0.08 and 0.46 +/- 0.10 of control, respectively. CONCLUSIONS: Propofol had no effect on nicorandil induced sarcolemmal KATP channel activities in rat aortic smooth muscle cells, whereas thiamylal significantly inhibited these channel activities at clinically relevant concentrations.

Adenosine Triphosphate↗

PubMedDate not supplied

Deep sedation with methohexital or thiamylal with midazolam for invasive procedures in children with acute lymphoblastic leukemia.

Pediatric oncology/hematology patients, especially those with acute lymphoblastic leukemia (ALL), often undergo repeated painful invasive procedures. Deep sedation, mandatory for these procedures in young children, can reduce patient anxiety and get their compliance during procedures. This study assessed clinical experience of employing methohexital or thiamylal with midazolam as sedative for elective invasive procedures in children with ALL. Between November 1997 and March 2004, 20 out of 33 ALL children received deep sedation after evaluation, mainly because of relatively young age (mean age 4.60 +/- 2.03 years). A total of 176 procedures were done, with 139 being intrathecal therapy. There were 98 and 78 procedures for the methohexital and thiamylal groups, respectively. The average dosages to complete the procedures were 2.2 +/- 1.2 mg/kg for methohexital and 3.4 +/- 2.1 mg/kg for thiamylal. One out of the 176 procedures was failed due to bradycardia, hypotension and cyanosis, in the methohexital group. Otherwise, no significant adverse events were found. Increased heart rate (HR) during stable blood pressure (BP) was observed in both groups. In conclusion, under careful monitoring and performed by experienced practitioners, the application of methohexital or thiamylal combined with midazolam to achieve deep sedation for invasive procedures in young children with ALL is safe.

Blood Pressure↗

PubMed1989

[Effect of thiamylal on superoxide generation in the cells and on lipid peroxidation of biological membranes].

The effect of thiamylal on the cellular superoxide generation and on membrane lipid peroxidation was examined. Active oxygens may play an important role in lung oxygen toxicity, since they attack the biological membranes and cause their lipid peroxidation. These active oxygens are generated in intra- and extra-cellular spaces in vivo. Under a certain condition, main part of intracellular superoxide generation is dependent on mitochondrial electron transport system. In this study, this superoxide generation was inhibited by the treatment with a low concentration of thiamylal concomitant with the uncoupling of mitochondrial oxidative phosphorylation. On the other hand, most part of extracellular superoxide is generated by the stimulation of phagocytotic cells such as neutrophils. This superoxide generation was also inhibited by the modification of cell membrane with thiamylal. Furthermore, the lipid peroxidation of mitochondria induced by Fe2+ was inhibited by the drug. Similar inhibitory action of the drug was observed on the superoxide dependent lipid peroxidation of Vitamin E deficient rat erythrocyte ghost or of phosphatidylinositol containing liposomal membranes. From these results, it was concluded that the thiamylal might act as a protective agent against the lung oxygen toxicity.

Animals↗

PubMed1979

Comparison of the cardiopulmonary effects of etomidate and thiamylal in dogs.

The cardiopulmonary effects of etomidate, a nonbarbiturate, short-acting, IV anesthetic, were compared and contrasted with those of thiamylal sodium in chronically instrumented conscious dogs. Etomidate, when administered IV at dosages of 1.5 and 3.0 mg/kg of body weight, produced anesthesia lasting from 8 +/- 5 and 21 +/- 9 minutes, respectively. Heart rate, aortic blood pressure, left ventricular peak pressure, left ventricular end diastolic pressure, left ventricular contractile force, and myocardial oxygen consumption were unchanged after administration of either dose of etomidate; however, the dosage of 1.5 mg/kg produced significant (P less than 0.05) increases in respiratory rate and decreases in tidal volume. The minute volume remained unchanged from base-line values. Significant (P less than 0.05) decreases in tidal volume, arterial pH, and partial pressure of oxygen were produced, and minute volume remained unchanged when 3.0 mg of etomidate/kg of body weight was administered. Thiamylal sodium (8.0 mg/kg of body weight; given IV) produced anesthesia lasting for 14 +/- 5 minutes. Significant increases (P less than 0.05) in heart rate, arterial blood pressure, left ventricular peak pressure, and myocardial oxygen consumption were observed after IV administration. Left ventricular contractility was significantly (P less than 0.05) decreased. Respiratory rate was not significantly (P less than 0.05) affected by thiamylal although tidal volume and minute volume were decreased. These respiratory alterations resulted in significant (P less than 0.05) increases in the arterial partial pressure of carbon dioxide and decreases in pH and the partial pressure of oxygen. On the basis of cardiopulmonary function, etomidate offered rapid, safe, short duration anesthesia superior to that of thiamylal sodium.

Animals↗

PubMed1984

Reinstatement of responding maintained by cocaine or thiamylal.

Rhesus monkeys were trained to self-administer one of two reference drugs, either cocaine or thiamylal. The lowest dose of cocaine or thiamylal which maintained responding was determined. Responding extinguished when saline was substituted for a reference drug. Then the effects of a variety of other drugs on saline self-administration were determined. In the cocaine-trained monkeys, the i.m. administration of d-methylamphetamine, cocaine, morphine or codeine during a session reinstated responding for saline infusions; in contrast, naloxone, chlorpromazine, dimethyltryptamine, diazepam and secobarbital did not. Naloxone blocked responding produced by the i.m. administration of morphine. In the thiamylal-trained monkeys, the administration of secobarbital (i.m.), pentobarbital (p.o.), butabarbital (p.o.) and phenobarbital (p.o.) reinstated responding for saline. The onset of behavioral responding was related to the pharmacokinetic properties of the drugs, with phenobarbital greater than pentobarbital = butabarbital. In contrast, cocaine and d-amphetamine i.m. failed to reinstate the responding in monkeys which had been trained to self-administer thiamylal. These data support the hypothesis that drugs producing responding at a rate significantly greater than that produced by vehicle controls share reinforcing properties with the reference drug.

Animals↗

PubMed1989

The effects of thiamylal sodium on the tonic vibration reflex in man.

The effects of barbiturate on the tonic vibration reflex (TVR) in man were studied. Motor unit spikes elicited during the TVR were recorded before and after an intravenous injection of thiamylal sodium. Thiamylal sodium at a dose between 1.5 and 5.8 mg/kg depressed the motor unit response to muscle vibration. Analysis using a cross-correlation between vibratory stimuli and motor unit spikes confirmed the previously reported existence of two types of motor unit response, i.e. spikes that are locked and those that are not locked to the vibratory stimuli. In addition, the latter type was susceptible to the depressant effects of thiamylal than the former type. Some possible explanations for the difference in susceptibility of the two types of motor unit to barbiturate are discussed, placing special emphasis on the probable participation of polysynaptic connections from group Ia afferents to motoneurons in the generation of the human TVR.

Adult↗

PubMedDate not supplied

Propofol versus thiamylal-enflurane anesthesia for outpatient laparoscopy.

STUDY OBJECTIVE: To determine whether propofol anesthesia differs from thiamylal-enflurane anesthesia in induction characteristics, intraoperative hemodynamics, postoperative side effects, and postoperative psychomotor function recovery. DESIGN: A randomized, double-blind, two-group study. SETTING: A large university hospital with gynecologic outpatient operations performed in an integrated operating room suite. PATIENTS: Sixty adult women (ASA physical status I or II) undergoing an outpatient gynecologic laparoscopic operation with an anesthesia time of approximately 60 minutes. INTERVENTIONS: No pharmacologic premedication. Pretreatment with intravenous droperidol 0.6 mg and sufentanil 0.2 micrograms/kg before induction of anesthesia. Anesthesia was induced with either thiamylal 4 mg/kg (Group 1) or propofol 2.5 mg/kg (Group 2). Anesthesia was maintained with either nitrous oxide (N2O) and enflurane, 2-0.5% inspired concentrations; (Group 1) or with a continuous infusion of propofol 200-100 micrograms/kg/min and N2O (Group 2). MEASUREMENTS AND MAIN RESULTS: In psychomotor function tests (Trieger dot test and p-deletion test) administered preoperatively and postoperatively, no difference was found between the groups. No difference was found in induction time, although significantly more patients reported pain after the propofol injection, or in intraoperative hemodynamics (mean arterial pressure and heart rate). Immediate recovery time (emergence from anesthesia) and intermediate recovery time (ambulation, oral intake, and discharge time) were significantly shorter after propofol anesthesia. Fewer postoperative side effects, such as nausea and vomiting, were reported after propofol anesthesia. CONCLUSIONS: Induction and maintenance of anesthesia with propofol were comparable to those with thiamylal-enflurane, except patients experienced more pain on injection after propofol. Both immediate and intermediate recovery were more rapid after propofol anesthesia compared with enflurane-based anesthesia.

Adult↗

PubMed2004

Extraction of thiamylal in serum using hydrophilic acetonitrile with subzero-temperature and salting-out methods.

For high-performance liquid chromatography (HPLC) of thiamylal, one of the barbiturates, the drug in serum samples was extracted by two alternative liquid-liquid extraction techniques using hydrophilic acetonitrile as a solvent and subzero-temperature and salting-out methods. Acetonitrile was mixed with the sample, separated by cooling at -20 degrees C or addition of sodium chloride, and injected directly into the HPLC apparatus. In both the methods, thiamylal was extracted effectively in the acetonitrile phase and pH adjustment of the sample was not required. The salting-out extraction method is rapid and would be suitable for quantitation of drugs in many samples. To avoid coextraction of added salt, the subzero-temperature extraction method was applied to identification of thiamylal by gas chromatography/mass spectrometry and liquid chromatography-tandem mass spectrometry.

Acetonitriles↗

PubMed1995

The effect of ketamine or thiamylal on succinylcholine-induced myoglobinemia under halothane anesthesia in adults.

We studied the effect of intravenous (IV) thiamylal or ketamine on the increases in serum myoglobin, creatine kinase (CK), and potassium induced by succinylcholine under halothane anesthesia. Ninety patients were divided into three groups. In Group O, succinylcholine (1.0 mg/kg) was administered after an the inhaled induction of anesthesia with halothane. In Group T, thiamylal (4.0-5.0 mg/kg), and in Group K, ketamine (1.5-2.0 mg/kg) was injected prior to succinylcholine administration. Anesthesia was maintained with halothane, nitrous oxide, and oxygen. Myoglobin increased in Group O at 60 min to 855 ng/mL (median) and CK to 98.6 IU/L. These increases were significantly higher than those of Group T (110 ng/mL and 66.4 IU/L) and Group K (110 ng/mL and 57.0 IU/L). Potassium increased in Group O only. There was no significant difference between Groups T and K for any of the three values. These results indicate that IV thiamylal and ketamine both suppress the increases of myoglobin, CK, and potassium, and that in cases when succinylcholine is used, both drugs can help to avoid myoglobinemia and limit the increases of CK and potassium.

Adolescent↗