thiopental and Body-Weight

Propofol is one of the most frequently applied intravenous anesthetics for the induction of general anesthesia. However, pain on injection of this agent is a considerable problem in daily anesthesia practice because of its severity. Administration of lidocaine prior to propofol injection is a standard technique for reducing the pain on injection. However, this method provides insufficient pain relief. To evaluate whether pretreatment with an ultra-short acting barbiturate, thiopental, is more effective than with lidocaine, a randomized and single-blinded trial was conducted. Patients (20-65 years old, n = 137) were allocated into six groups, and applied with physiological saline, thiopental (25, 50, 75, or 100 mg), or lidocaine (40 mg) at 30 second prior to propofol injection (1 mg/kg, 1200 ml/h). The patient was interviewed about the degree of pain just after propofol was totally injected. Both thiopental (> or =25 mg) and lidocaine decreased the severity of pain in comparison with physiological saline as evaluated by a six-graded pain score. Lidocaine failed to influence the incidence of pain (from 86% to 55%), although thiopental significantly decreased it to 40% (25 mg), 21% (50 mg), 12% (50 mg), and 0% (100 mg), respectively. Thiopental (> or =50 mg) decreased both the severity and incidence of pain more effectively than lidocaine. A Hill plot analysis of these data, after rearrangement by patient's body weight, estimated that the half-effective dose (ED50) and the ED99 of this drug to block pain on injection of propofol were 0.6 and 1.4 mg/kg, respectively.

Topics: Adult; Aged; Anesthetics, Intravenous; Anesthetics, Local; Body Weight; Dose-Response Relationship, Drug; Humans; Hypnotics and Sedatives; Injections; Lidocaine; Middle Aged; Pain; Pain Measurement; Preanesthetic Medication; Propofol; Thiopental

(1) To investigate changes in arterial oxygen saturation via pulse oximeter (SpO2) during apnea and after reinstitution of manual ventilation at SpO2 of 95% or 90% following rapid sequence induction of anesthesia in children after 2-minute preoxygenation; (2) to determine whether the setting of a safe threshold of apneic period to an SpO2 of 95% is appropriate in children during anesthetic induction; and (3) to evaluate the influences of age, body weight, and height on the time from the start of apnea to SpO2 of 95%.. A clinical study of random design and comparison among groups.. Operating room of a plastic surgery hospital of the Chinese Academy of Medical Sciences and Peking Union Medical College.. 152 infants and children, ASA physical status 1, aged 3 months to 12 years, scheduled for elective plastic surgery.. Patients were divided into three age groups: Group 1-infants 3 months to 1 year (n = 39); Group 2 children 1 to 3 years (n = 41); and Group 3-children 3 to 12 years (n = 72). Patients in each age group were randomly allocated again to Subgroups A and B. After a 2-minute preoxygenation, anesthesia was induced with thiopental 5 mg/kg, fentanyl 5 micrograms/kg and suxamethonium 1.5 mg/kg. Patients were manually ventilated when SpO2 decreased to 90% in Subgroups A and 95% in Subgroups B, respectively, during apnea.. SpO2 was measured continuously with a Datex pulse oximeter applied to the right index finger. During apnea, the times for SpO2 to decrease to 09% (T99) and 95% (T99) in all children, and 90% (T90) in Subgroups A were recorded. The time for SpO2 to decrease from 95% to 90% (T95-90) in Subgroups A was also measured. After reinstitution of manual ventilation, the time when SpO2 continued to decrease (T1) and the time from the end of apnea to recovery of SpO2 baseline (T2) were determined. In addition, the lowest value of SpO2 after apnea was also recorded. The results showed that younger children were more susceptible than older children to the risk of hypoxemia during apnea. There were significant differences in T99, T95, T90, and T95-90 between the three age groups T1 and T2 were significantly longer in Group 3 than in Groups 1 and 2. There were significant differences in the lowest values of SpO2 following apnea among the three Subgroups A and between Subgroups A and B of each age group. During apnea, heart rate decreased gradually as SpO2 decreased, showing a significant decrease at SpO2 of 95%. Bradycardia was found in three children in Subgroups A. The apnea time to SpO2 of 95% correlated well with age, weight, and height by linear regression analysis.. The safe threshold of an apneic period setting to an SpO2 of 95% was appropriate in children during anesthesia induction. Despite the same duration of preoxygenation, younger children were more susceptible than elder ones to the risk of hypoxemia during apnea. The apnea time to SpO2 of 95% correlated with age, body weight, and height using linear regression analysis.

Topics: Age Factors; Anesthesia, Intravenous; Anesthetics, Intravenous; Apnea; Body Height; Body Weight; Bradycardia; Child; Child, Preschool; Disease Susceptibility; Elective Surgical Procedures; Fentanyl; Heart Rate; Humans; Hypoxia; Infant; Linear Models; Neuromuscular Depolarizing Agents; Oximetry; Oxygen; Respiration, Artificial; Risk Factors; Safety; Succinylcholine; Surgery, Plastic; Thiopental; Time Factors

The influence of rectal administration of barbiturates on PCO2 during mask anaesthesia with spontaneous ventilation was studied in 72 infants. The age of the patients ranged between 6 and 24 months and they were all subjected to minor paediatric surgery. The patients were divided into four equally large groups: a control group receiving no premedication, a group receiving rectal thiopentone 30 mg X kg-1 and two groups receiving methohexitone either 20 or 30 mg X kg-1. In all patients PCO2 was measured in an arterialized capillary blood sample obtained during stable anaesthesia with oxygen, nitrous oxide and halothane before and after surgery. After rectal induction with barbiturates, the mean PCO2 was significantly higher in the different barbiturate groups than in the control group (P less than 0.05). The mean PCO2 value +/- s.d. in kPa for the control group was 5.6 +/- 0.7, for the group receiving thiopentone 30 mg X kg-1 6.5 +/- 1.6, for the groups receiving methohexitone 20 or 30 mg X kg-1 6.1 +/- 1.2 and 6.3 +/- 1.1, respectively. It is concluded that the combination of rectal induction with barbiturates and mask anaesthesia with oxygen, nitrous oxide and halothane carries an increased risk of hypoventilation in infants under 2 years of age.

Topics: Administration, Rectal; Anesthesia; Body Weight; Carbon Dioxide; Humans; Infant; Methohexital; Preanesthetic Medication; Respiration; Thiopental

Thiopentone elimination has been described using Michaelis-Menten pharmacokinetics in adults after prolonged infusion or overdose, but there are few reports of elimination in neonates.. Time-concentration profiles for neonates (n=37) given single-dose thiopentone were examined using both first-order (constant clearance) and mixed-order (Michaelis-Menten) elimination processes using nonlinear mixed effects models. These profiles included a 33-week post-menstrual age (PMA) neonate given an overdose. A two-compartment mamillary model was used to fit data. Parameter estimates were standardized to a 70 kg person using allometric models.. There were 197 observations available for analysis from neonates with a mean post-menstrual age of 35 (SD 4.5) weeks and a mean weight of 2.5 (SD 0.9) kg. They were given a mean thiopentone dose of 3 (SD 0.4) mg/kg as a rapid bolus. Clearance at 26 weeks PMA was 0.015 l/min/70 kg and increased to 0.119 l/min/70 kg by 42 weeks PMA. The maximum rate of elimination (V(max)) at 26 weeks PMA was 0.22 mg/min/70 kg and increased to 4.13 mg/min/70 kg by 42 weeks PMA. These parameter estimates are approximately 40% adult values at term gestation. The Michaelis constant (K(m)) was 28.3 [between subject variability (BSV) 46.4%, 95% confidence interval (CI) 4.49-99.2] mg/l; intercompartment clearance was 0.44 (BSV 97.5%, 95% CI 0.27-0.63) l/min/70 kg; central volume of distribution was 46.4 (BSV 29.2%, 95% CI 41.7-59.8) l/70 kg; peripheral volume of distribution was 95.7 (BSV 70.3%, 95% CI 61.3-128) l/70 kg.. Both first-order and mixed-order processes satisfactorily described elimination. First-order elimination adequately described the time-concentration profile in the premature neonate given an overdose. Clearance is immature in the pre-term neonate although there is rapid maturation around 40 weeks PMA, irrespective of post-natal age.

Topics: Adult; Algorithms; Bayes Theorem; Body Weight; Chromatography, High Pressure Liquid; Data Interpretation, Statistical; Drug Overdose; Gestational Age; Humans; Hypnotics and Sedatives; Infant, Newborn; Infant, Premature; Nonlinear Dynamics; Population; Thiopental

Thiopentone, a short-acting barbiturate, has been introduced as premedication for intubation in newborn infants. The objectives of this study were to assess the pharmacokinetics of thiopentone in newborn infants, and to unravel whether placental transfer of the drug should be taken into account if administered to infants exposed to it during delivery.. Plasma concentrations were assessed with high-pressure liquid chromatography in samples from delivering mothers (n=27) receiving a median dose of 5.5 mg/kg (range 3.8-7.7) thiopentone for Caesarean section in gestational week 37.6 (range 25.7-41.4) and from corresponding umbilical cord blood (n=28). In infants (n=30) born at 35.4 weeks gestation (range 27.9-42.0) undergoing surgery at a median postnatal age of 24.5 h (range 4-521), repeated blood levels were assessed after administering a dose of 3 mg/kg thiopentone on clinical indication before intubation (seven samples per infant from 5 min to 48 h after administration).. The umbilical/maternal concentration ratio was 0.7, the mean concentration of thiopentone was 55.7 micromol/l (SD+/-15.3) in mothers and 39.3 micromol/l (SD+/-12.5) in venous cord blood. In newborn infants undergoing surgery, the terminal half-life of thiopentone was 8 h (interquartile range (IQR) 2.5-10.8), and clearance 0.092 l/min per kg/postnatal age in days (IQR 0.02-0.1).. Thiopentone might be used as premedication for short-lasting intubation after birth, for example, for surfactant administration. During the first 4 h after birth the dose needs to be adjusted for maternal dosage as well as for the weight of the infant.

Topics: Anesthesia, General; Anesthesia, Obstetrical; Body Weight; Cesarean Section; Chromatography, High Pressure Liquid; Congenital Abnormalities; Drug Administration Schedule; Female; Fetal Blood; Half-Life; Humans; Hypnotics and Sedatives; Infant, Newborn; Male; Maternal-Fetal Exchange; Placenta; Pregnancy; Premedication; Prospective Studies; Thiopental

The Dutch 'euthanasia and assisted suicide' practice guideline advises using 2000 mg thiopental to induce coma, followed by a muscle relaxant to cause death by respiratory paralysis. However, when a doctor administers such a high dose of thiopental as a bolus injection to a cachectic patient, there is a high likelihood of immediate death and other side effects, which can be distressing for the family. Doctors who administered less than 2000 mg have been reprimanded for not working according to current standards. Arguments are given concerning in which circumstances it is reasonable to use the advised dose of 2000 mg of thiopental and when to use less thiopental to induce coma by direct intravenous injection. The author suggests that it may be better to adjust the dose of thiopental according to the body weight of the patient. The current practice guideline needs revision.

Topics: Anesthetics, Intravenous; Body Weight; Drug Dosage Calculations; Euthanasia, Active, Voluntary; Humans; Injections, Intravenous; Netherlands; Thiopental

Modeling of pharmacokinetic parameters and pharmacodynamic actions requires knowledge of the arterial blood concentration. In most cases, experimental measurements are only available for a peripheral vein (usually antecubital) whose concentration may differ significantly from both arterial and central vein concentration.. A physiologically based pharmacokinetic (PBPK) model for the tissues drained by the antecubital vein (referred to as "arm") is developed. It is assumed that the "arm" is composed of tissues with identical properties (partition coefficient, blood flow/gm) as the whole body tissues plus a new "tissue" representing skin arteriovenous shunts. The antecubital vein concentration depends on the following parameters: the fraction of "arm" blood flow contributed by muscle, skin, adipose, connective tissue and arteriovenous shunts, and the flow per gram of the arteriovenous shunt. The value of these parameters was investigated using simultaneous experimental measurements of arterial and antecubital concentrations for eight solutes: ethanol, thiopental, 99Tcm-diethylene triamine pentaacetate (DTPA), ketamine, D2O, acetone, methylene chloride and toluene. A new procedure is described that can be used to determine the arterial concentration for an arbitrary solute by deconvolution of the antecubital concentration. These procedures are implemented in PKQuest, a general PBPK program that is freely distributed http://www.pkquest.com.. One set of "standard arm" parameters provides an adequate description of the arterial/antecubital vein concentration for ethanol, DTPA, thiopental and ketamine. A significantly different set of "arm" parameters was required to describe the data for D2O, acetone, methylene chloride and toluene - probably because the "arm" is in a different physiological state.. Using the set of "standard arm" parameters, the antecubital vein concentration can be used to determine the whole body PBPK model parameters for an arbitrary solute without any additional adjustable parameters. Also, the antecubital vein concentration can be used to estimate the arterial concentration for an arbitrary input for solutes for which no arterial concentration data is available.

Topics: Acetone; Adult; Algorithms; Arteries; Body Weight; Deuterium Oxide; Drug Administration Schedule; Elbow; Ethanol; Humans; Ketamine; Male; Methylene Chloride; Models, Biological; Pharmacokinetics; Regional Blood Flow; Technetium Tc 99m Pentetate; Thiopental; Toluene; Veins

To investigate the relationship between total body weight (TBW) or body mass index (BMI) and atracurium reversal time.. The study population comprised 25 patients with TBW < 80 kg and 25 patients with TBW > or = 80 kg anaesthetised with midazolam, thiopentone, fentanyl, nitrous oxide and halothane. Neuromuscular block was induced with 0.5 mg.kg-1 atracurium and maintained with doses of 0.15 mg.kg-1. Neuromuscular transmission was recorded using train-of-four (TOF) nerve stimulation and mechanomyography. Neostigmine, 0.07 mg.kg-1, was administered when the first twitch in TOF had recovered to 10% of control. Reversal time was defined as: time from administration of neostigmine until TOF ratio recovered to 0.70.. There was no difference in reversal time between patients with TBW < 80 kg (7.2 +/- 2.6 min, mean +/- SD), and patients with TBW > or = 80 kg (6.9 +/- 3.6 min). When patients were grouped according to BMI there was no difference in reversal time between groups with low BMI (6.9 +/- 2.6 min) or high BMI (7.1 +/- 3.6 min). There was, furthermore, no difference in reversal time between the 15 patients in the study population with the smallest TBW or BMI and the 15 patients with the greatest TBW or BMI. There was no correlation between TBW or BMI and reversal time.. When atracurium-induced neuromuscular block is antagonised with 0.07 mg.kg-1 neostigmine. TBW or BMI have no influence on reversal time.

Topics: Adult; Anesthetics, Inhalation; Anesthetics, Intravenous; Atracurium; Body Mass Index; Body Weight; Cholinesterase Inhibitors; Electric Stimulation; Female; Fentanyl; Halothane; Humans; Midazolam; Middle Aged; Muscle Contraction; Muscle, Skeletal; Neostigmine; Neuromuscular Blockade; Neuromuscular Junction; Neuromuscular Nondepolarizing Agents; Nitrous Oxide; Obesity; Synaptic Transmission; Thiopental; Time Factors; Ulnar Nerve

To evaluate the effect of gender on the pharmacokinetics of vecuronium, we studied 30 patients (15 male and 15 female) undergoing elective plastic surgery with anticipated surgical blood loss of <300 mL under general anesthesia. General anesthesia was induced with thiopental 4-6 mg/kg and fentanyl 2-4 microg/kg and was maintained with 60% nitrous oxide in oxygen and an end-tidal concentration of 1.5%-2% enflurane. After a 2-min infusion of vecuronium 100 microg/kg, a modified fluorometric assay was used to determine the plasma concentrations of vecuronium for 5 h. The results showed that, compared with women, the plasma concentrations of vecuronium in men were significantly lower during the first 20 min and that the disposition kinetics of vecuronium can be best described mathematically by a three-compartment open model in the two groups. The volume of the central compartment and the volume of distribution at steady state were 39.6 +/- 8.6 and 164.8 +/- 29.3 mL/kg, respectively, in women. These values increased significantly to 54.4 +/- 14.4 and 201.4 +/- 75.8 mL/kg in men (P < 0.05). When the data were calculated on the basis of ideal body weight, the volume of distribution of vecuronium was also different between men and women (P < 0.05. The half-lives of fast distribution and distribution, the elimination half-life, mean residual time, area under the plasma-concentration curve, and plasma clearance were not different between the two groups. We conclude that the pharmacokinetics of vecuronium are significantly different between genders and that and men have the greater volume of distribution of vecuronium.. The authors found that, compared with women, men had lower plasma concentrations of vecuronium after the i.v. administration of vecuronium and a larger volume of distribution of vecuronium. The pharmacokinetic differences may be related to the differences in the sensitivity to vecuronium between genders.

Topics: Adolescent; Adult; Anesthetics, Inhalation; Anesthetics, Intravenous; Area Under Curve; Blood Loss, Surgical; Body Weight; Elective Surgical Procedures; Enflurane; Female; Fentanyl; Half-Life; Humans; Injections, Intravenous; Male; Metabolic Clearance Rate; Models, Chemical; Neuromuscular Nondepolarizing Agents; Nitrous Oxide; Plastic Surgery Procedures; Sex Characteristics; Thiopental; Time Factors; Vecuronium Bromide

Anesthetic requirements for inhalational agents are decreased during pregnancy, but there are no data regarding requirements for intravenous agents. The quantal dose-response curves for thiopental were calculated for 70 nonpregnant women having gynecologic surgery and for 70 pregnant women of 7-13 weeks' gestation having elective abortions.. Groups of 10 patients were given 2, 2.4, 2.8, 3.3, 3.8, 4.5, or 5.3 mg/kg thiopental as a bolus dose during a period of 10 s. Two minutes later, patients were asked to open their eyes as a test for hypnosis. Patients who did not open their eyes were given a 10-s, 50-Hz, 80-mA transcutaneous tetanic electrical stimulus to the ulnar nerve as a test for anesthesia. Purposeful movement indicated that there was no anesthesia. Log dose-response curves for hypnosis and anesthesia were calculated after logit transformation.. In the nonpregnant women, the median effective doses (ED50s) (95% confidence interval) for hypnosis and anesthesia were 3.1 (2.8-3.4) mg/kg and 4.9 (4.5-5.4) mg/kg, whereas in the pregnant women the corresponding ED50s were 2.6 (2.3-2.8) mg/kg and 4 (3.7-4.4) mg/kg. In the non-pregnant women, the ED95s (95% CI) for hypnosis and anesthesia were 4.4 (3.9-5.4) mg/kg and 6.4 (5.7-7.9) mg/kg, whereas in the pregnant women the corresponding ED95s were 3.7 (3.3-4.5) mg/kg and 5.2 (4.7-6.3) mg/kg. The pregnant to nonpregnant relative median potency (95% CI) ratio for hypnosis was 0.83 (0.67-0.96) and for anesthesia it was 0.82 (0.62-0.94).. The dose of thiopental for hypnosis was 17% less and that for anesthesia was 18% less in pregnant women of 7-13 weeks' gestation compared with that in nonpregnant women.

Topics: Adult; Anesthetics, Intravenous; Body Weight; Dose-Response Relationship, Drug; Female; Humans; Pregnancy; Pregnancy Trimester, First; Thiopental

The ultrasonographic appearance of the equine triceps muscle of clinically normal horses, before and after general anaesthesia, was investigated and compared with 5 cases of post anaesthetic myopathy. The triceps muscle areas were examined bilaterally using a 7.5 MHz linear array probe in 2 different planes, with each limb both weightbearing and nonweightbearing. The triceps muscles of 4 unanaesthetised horses were scanned twice, 24 h apart. Six horses underwent general anaesthesia and were scanned pre-anaesthesia and at 1 and 24 h intervals after recovery. Blood samples were obtained in the unanaesthetised group at each scan time and, in the anaesthetised group, pre-anaesthesia and at 10 min, 5 and 24 h after recovery. Creatine kinase (CK) and aspartate aminotransferase (AST) concentrations were measured. Anaesthetic details and recovery were related to the ultrasonographic and muscle enzyme findings. Five horses with post anaesthetic myopathy were scanned at intervals after the onset of clinical signs. In normal horses, the triceps muscle appeared ultrasonographically as echoic striations separated by anechoic areas. The fascia dividing muscle bellies was visible as an echoic line. Ultrasonographs obtained with the limb nonweightbearing had no change or a slight overall increase in echogenicity. The scans of control unanaesthetised horses were unchanged on successive days. All anaesthetised horses had uncomplicated anaesthesia and recoveries and did not exhibit any clinical signs of post anaesthetic myopathy. Elevated CK and AST values were found up to 342 and 195%, respectively, of the pre-anaesthetic values but no significant alterations in the ultrasonographic appearance of the muscles were detected. Clinical cases of post anaesthetic myopathy had disruption of the normal ultrasonographic pattern. There was an overall increase in echogenicity with a loss of the normal striated pattern. In 3 cases, there was localised increased echogenicity within the muscle. One of these horses was humanely destroyed for other reasons and histological examination of the affected muscle revealed a necrotic area correlating with the hyperechoic region. Two horses had bilateral involvement of the triceps musculature. Four horses recovered clinically from the myopathy and the ultrasonographic appearance returned to normal except in 1 horse where focal hyperechoic regions remained 10 weeks after the onset of the clinical signs.

Topics: Anesthesia Recovery Period; Anesthesia, General; Anesthetics, General; Animals; Aspartate Aminotransferases; Body Weight; Creatine Kinase; Female; Horses; Injections, Intravenous; Ketamine; Male; Muscle, Skeletal; Thiopental; Ultrasonography

Topics: Animals; Body Weight; Cytochrome P-450 Enzyme System; Liver; Male; Mice; Mice, Inbred BALB C; Organ Size; Schistosomiasis; Thiopental; Zoxazolamine

Topics: Anesthesia, Intravenous; Animals; Body Weight; Diazepam; Ketamine; Thiopental

Dose requirements for thiopental anesthetic induction have significant age- and gender-related variability. We studied the association of the patient characteristics age, gender, weight, lean body mass, and cardiac output with thiopental requirements. Doses of thiopental, infused at 150 mg/min, required to reach both a clinical end-point and an electroencephalographic (EEG) end-point were determined in 30 males and 30 females, aged 18-83 yr. Univariate least squares linear regression analysis revealed outliers in the relationships of age, weight, lean body mass, and cardiac output to thiopental dose at clinical and EEG endpoints. Differential weighting of data points minimized the effect of outliers in the construction of a robust multiple linear regression model of the relationship between several selected independent variables and the dependent variables thiopental dose at clinical and EEG endpoints. The multiple linear regression model for thiopental dose at the clinical end-point selecting the regressor variables age, weight, and gender (R2 = 0.76) was similar to that for age, lean body mass, and gender (R2 = 0.75). Thiopental dose at the EEG endpoint was better described by models selecting the variables age, weight, and cardiac output (R2 = 0.88) or age, lean body mass, and cardiac output (R2 = 0.87). Although cardiac output varied with age, age always remained a selected variable. Because weight and lean body mass differed with gender, their selection as variables in the model eliminated gender as a selected variable or minimized its importance.

Topics: Adult; Age Factors; Aged; Aged, 80 and over; Anesthesia, General; Body Height; Body Mass Index; Body Weight; Cardiac Output; Dose-Response Relationship, Drug; Electroencephalography; Female; Humans; Infusions, Intravenous; Male; Middle Aged; Regression Analysis; Sex Factors; Thiopental

The extent of atelectasis was correlated to constitutional factors in 38 patients who underwent computed tomography prior to and during general anaesthesia with halothane. All patients but two developed atelectasis in dependent regions of both lungs immediately after induction of anaesthesia prior to surgery. The transverse area of the densities ranged from 0 to 27 cm2, and there were no significant differences between patients of different age or sex, or with different smoking habits. A significant linear regression was found between Broca's index weight (kg)/height (cm)-100 and the area of the densities, and also between an index describing the shape of the thorax and the density area. Thus, patients who were overweight and/or had a low and wide thorax tended to develop more extensive atelectasis during anaesthesia. This finding might partly explain why overweight patients develop postoperative pulmonary complications more often than non-obese patients.

Topics: Adult; Aged; Anesthesia, General; Body Constitution; Body Height; Body Weight; Female; Fentanyl; Halothane; Humans; Intraoperative Complications; Male; Middle Aged; Pulmonary Atelectasis; Thiopental; Tomography, X-Ray Computed

Images of a saggital section of the right hemidiaphragm were obtained using an ultrasound sector scanner in 20 patients in the supine position immediately before, and after, the induction of anaesthesia (with thiopentone). In the awake patient, the mean excursion of the part of the diaphragm that showed the greatest tidal movement was 1.56 +/- 0.52 (SD) cm. The end-expiratory position of this part of the diaphragm was noted before and after induction. Craniad movement of this position was seen in 10 patients. In a further eight, the end-expiratory position did not change, and in two patients it moved caudally. The mean movement was 0.36 +/- 0.52 cm in a cranial direction, which was statistically significant (P less than 0.01) but was only 23% of the movement associated with quiet breathing. The extent or direction of movement was not related to the weight of the patient (expressed as a proportion of the expected weight). The findings do not support the hypothesis that the reduction of lung volume on induction of anaesthesia is caused solely by movement of the diaphragm.

Topics: Adult; Aged; Anesthesia, Intravenous; Body Weight; Diaphragm; Female; Humans; Male; Middle Aged; Movement; Respiration; Thiopental; Ultrasonography

The effect of chronic alcohol intake on anesthetic responses to alcohol, thiopental, or diazepam was examined in adult male Sprague-Dawley rats. Alcohol-fed animals were maintained solely on a complete balanced liquid diet containing 6.54% ethanol (w/w) for 21 days; pair-fed control animals received equal amounts of the same diet with alcohol isocalorically replaced by sucrose or dextrin. Nine hours after diets were withdrawn on the twenty-second day, the following drug/dose combinations were administered intraperitoneally to separate groups of alcohol-fed and control rats (10-15 animals in each group): ethanol 2.4, 3.2, and 4.0 g/kg; thiopental 20, 40, and 80 mg/kg; and diazepam 10, 20, and 40 mg/kg. Three different responses were assessed in every animal: 1) loss of righting reflex (induction of anesthesia); 2) response to a painful stimulus (analgesia); and 3) sleeping time (duration of anesthesia). Alcohol-fed rats compared with controls were significantly less tolerant of pain at an acute alcohol dose of 2.4 g/kg, and loss of righting reflex and sleeping time were reduced at 4.0 g/kg. All three anesthetic responses were also attenuated in alcohol-fed rats at a diazepam dose of 20 mg/kg. In contrast, none of the three responses was reduced in alcohol-fed rats at any of the three thiopental doses. Thus, chronic alcohol intake sufficient to produce tolerance to anesthetic doses of alcohol in rats also produced cross-tolerance to diazepam but not to thiopental in equianesthetic doses. These results suggest that blanket recommendations for adjusting intravenous anesthetic dosages in alcoholic humans may be inadequate as guides to anesthetic management.

Topics: Alcoholism; Anesthesia, Intravenous; Animals; Body Weight; Diazepam; Drug Interactions; Drug Tolerance; Ethanol; Male; Rats; Rats, Inbred Strains; Thiopental

CNS-sensitivity to hexobarbital and thiopental was determined with an EEG-threshold method in rats of different ages. The results show that the threshold dose decreases by 15% for both barbiturates when the rats are between 50 and 150 days of age. Brain concentrations of hexobarbital also decreased with increasing age and show that the changes in threshold doses are due to changes in CNS-sensitivity. Anesthesia times after threshold determinations decrease with increasing age for thiopental, but there was no change in anesthesia times after hexobarbital thresholds. At 90-100 days of age there was a significant increase in EEG-threshold for hexobarbital, and brain concentrations in the same age interval indicate a decreased CNS-sensitivity.

Topics: Aging; Anesthesia; Animals; Body Weight; Brain; Brain Chemistry; Electroencephalography; Hexobarbital; Male; Rats; Rats, Inbred Strains; Thiopental

Intragastric pressure was measured in 20 patients before, and immediately after, the induction of anaesthesia with thiopentone. Intragastric pressure decreased in patients whose weights were the same as or less than expected, and increased in five of seven patients whose weights were greater than expected (P = 0.0013). These findings suggest that the decrease in FRC known to occur on the induction of anaesthesia is caused by a decrease in inspiratory muscle tone in the diaphragm and other muscles.

Topics: Adult; Aged; Anesthesia, Intravenous; Body Weight; Humans; Middle Aged; Pressure; Stomach; Thiopental; Time Factors

The average induction dose of thiopentone did not differ significantly when eight young women were compared with eight young men. In neither group did the dose increase with increased body weight. Clearance of thiopentone from venous blood was described by a three-compartment open model. The average volumes of V1 and V3 were greater in the females, but only the difference between the V3 values was significant (P < 0.05). Significant correlations (P < 0.01) were found between the initial drug concentrations and the k12 values. The slopes of the regression lines were 0.0029 for the women and 0.0038 for the men (0.1 < P < 0.2). It is suggested that the redistribution rate constant k12 is predominant in determining the sleep dose rather than the initial distribution volume V1.

Topics: Adult; Anesthesia, Intravenous; Body Weight; Dose-Response Relationship, Drug; Female; Humans; Kinetics; Male; Models, Biological; Sex Factors; Thiopental

Myocardial infarction was produced in dogs and cats by occlusion of the left anterior descending coronary artery. Arrhythmia was present in dogs but not in cats 6 to 48 h after occlusion. The absence of arrhythmia in cats was not due to persistent myocardial depressant effects of anaesthesia administered during surgery. Studies in cats with surgically-induced heart block revealed multiple ventricular pacemakers but no change in average ventricular rate following coronary occlusion. These results suggest that sinus overdrive, although not elevated compared with the dog, is sufficient to suppress arrhythmia in the cat. Further, since small dogs developed significantly less arrhythmia than large dogs, heart size may be an additional factor in explaining the absence of arrhythmia in the cat.

Topics: Animals; Arrhythmias, Cardiac; Atrioventricular Node; Body Weight; Cats; Disease Models, Animal; Dogs; Female; Heart; Heart Conduction System; Heart Ventricles; Male; Myocardial Infarction; Organ Size; Thiopental; Vagus Nerve

An overall analysis was made of 4763 case report forms from 45 anesthesiologists who used etomidate (Hypnomidate) routinely as an induction hypnotic in a total of 4127 surgical cases or compared it to thiopental in a series of controlled studies (325 on etomidate, 311 on thiopental). Premedication was standardized only in the controlled studies, and there were no restrictions on the use of anesthetic agents or techniques. Etomidate proved to be a safe and effective induction hypnotic. Sleep was deep and long enough to allow the normal induction and maintenance procedures. Blood pressure and heart rate remained remarkably stable in the 3 study groups. The incidence of respiratory depression was higher for thiopental; anesthesiologists' acceptance of etomidate was, however, reduced by the occurrence of venous pain during injection and of associated involuntary muscle movements. It is expected that these adverse effects will be largely eliminated by using the recently introduced new formulation of etomidate shortly after fentanyl.

Topics: Adolescent; Adult; Age Factors; Aged; Blood Pressure; Body Weight; Child; Child, Preschool; Etomidate; Fentanyl; Heart Rate; Humans; Imidazoles; Infant; Middle Aged; Premedication; Thiopental; Time Factors

The uptake and distribution of two i.v. anaesthetics agents, thiopentone and Althesin, were studied in mice with normal and subnormal nutritional states. The results show that, following the administration of thiopentone, the induction time was signficantly shorter, and that the sleeping time was significantly longer following the administration of Althesin and thiopentone in mice that have low net protein utilization, and decreased total and dry body mass. The increase in the sleeping time in these undernourished mice was 2.2 times greater for Althesin and 4.0 times greater for thiopentone when compared with well-nourished mice.

Topics: Alfaxalone Alfadolone Mixture; Anesthesia, Intravenous; Animals; Body Weight; Hematocrit; Mice; Nutrition Disorders; Pregnanediones; Sleep; Thiopental; Time Factors

Topics: Adolescent; Adult; Age Factors; Aged; Body Weight; Female; Humans; Male; Middle Aged; Thiopental

The effect of pre-operative starvation, anaesthesia and surgery on blood sugar levels and the handling of carbohydrate load during operation were studied in 28 Nigerian children between 2 months and 15 years of age. (1) Age and body weight were important factors influencing the relationship between duration of pre-operative fast and the pre-induction blood sugar level in children. Hypoglycaemic values occurred in 7 per cent of the subjects studied although none was clinically hypoglycaemic. (2) Halothane anaesthesia alone did not affect blood sugar levels but relaxant anaesthesia in this study caused significant rise of blood sugar. (3) There was a marked hyperglycaemic response to surgery and handling of glucose load during operation was significantly poorer than before operation.

Topics: Adolescent; Age Factors; Anesthesia; Black People; Blood Glucose; Body Weight; Carbohydrate Metabolism; Child; Child, Preschool; Fasting; Female; Glucose Tolerance Test; Halothane; Humans; Infant; Male; Nigeria; Preoperative Care; Surgical Procedures, Operative; Thiopental

The effect of the anaesthetic procedures and of the sex, age and weight of each patient on glucose uptake and glycogen content of human skeletal muscle has been studied in vitro in the presence and absence of insulin. Statistical analysis indicated that the relationships between age and both glucose uptake and the response to insulin were significant, older patients in general having higher uptakes. The blucose uptake was highly correlated with the three obesity indices (ponderal index, body mass index and percentage of the ideal weight). The anaesthetic agents had no significant effect on glucose uptake. The choice of premedication appeared to have a small effect on the basal glucose uptake level, but as the choice of premedication was also age related and age itself was a significant factor, this effect may not be of importance. It is concluded that the age and the degree of obesity of the patients ought to be taken into account when studying samples of human muscle.

Topics: Adult; Age Factors; Aged; Anesthesia; Atropine; Body Weight; Female; Glucose; Glycogen; Humans; Male; Meperidine; Middle Aged; Muscles; Papaverine; Preanesthetic Medication; Scopolamine; Thiopental

Ethanol was administered chronically for 14 days to male Sprague-Dawley rats. Day 15 was ethanol-free. On day 16 the rats received 25 mg of thiopental per kilogram (intravenously). One minute after the injection, the ethanol-treated rats showed lower blood levels of thiopental and higher liver levels of the drug than control rats given sucrose in place of ethanol. Samples of blood drawn 5 and 10 min after injection showed no significant difference in thiopental levels between the ethanol and control groups. The ethanol-treated group slept for a significantly shorter period of time. It is concluded that chronic ethanol consumption for 14 days decreases the pharmacological effects of thiopental and alters its initial distribution in the body.

Topics: Animals; Body Weight; Ethanol; Male; Rats; Sleep; Sulfur Radioisotopes; Thiopental; Time Factors

Topics: Adjuvants, Anesthesia; Adult; Anesthesia, General; Atropine; Body Height; Body Weight; Carbon Dioxide; Cholinesterases; Depression, Chemical; Drug Combinations; Female; Humans; Hydroxysteroids; In Vitro Techniques; Male; Meperidine; Middle Aged; Nitrous Oxide; Partial Pressure; Potassium; Preanesthetic Medication; Pregnanediones; Stimulation, Chemical; Succinylcholine; Thiopental; Time Factors

Topics: Adolescent; Adult; Age Factors; Aged; Anesthesia; Body Weight; Electric Stimulation; Electrodes; Female; Halothane; Humans; Male; Middle Aged; Neural Inhibition; Nitrous Oxide; Preanesthetic Medication; Radioimmunoassay; Sex Factors; Thiopental; Thumb; Tubocurarine; Ulnar Nerve

Topics: Animals; Body Weight; Cerebrovascular Circulation; Dogs; Dose-Response Relationship, Drug; Female; Male; Thiopental

Functional residual capacity has been measured by helium dilution in 26 spontaneously breathing patients before and immediately after anaesthesia, which was induced with thiopentone and maintained with halothane. The mean reduction was 390 ml (16.1% or pre-induction value) and the change was highly significant (P less than 0.001). The decrease in FRC correlated with age (r equals 0.41: P less than 0.005) and less (P less than 0.001). The decrease in FRC correlated with age (r equals 0.41; P less than 0.005) and less satisfactorily with the weight/height ratio (r equals 0.31; P less than 0.05) which itself correlated with age. Inspired oxygen concentration, expiratory reserve volume and the presence of phasic expiratory muscle activity bore no significant relationship to the decrease in FRC. There was no evidence of any progressive change in FRC between 6 and 20 min after the induction of anaesthesia.

Topics: Adult; Age Factors; Aged; Anesthesia, Inhalation; Body Height; Body Weight; Electromyography; Halothane; Helium; Humans; Indicator Dilution Techniques; Intercostal Muscles; Lung Compliance; Lung Volume Measurements; Male; Middle Aged; Oxygen; Residual Volume; Respiration; Spirometry; Thiopental; Time Factors

Topics: Anesthesia, Rectal; Body Weight; Child; Child, Preschool; Drug Evaluation; Female; Humans; Infant; Male; Preanesthetic Medication; Suppositories; Thiopental; Time Factors

Topics: Abortion, Therapeutic; Adult; Anesthesia, Inhalation; Anesthesia, Intravenous; Anesthesia, Obstetrical; Body Weight; Dreams; Female; Humans; Ketamine; Nitrous Oxide; Oxygen; Pregnancy; Prospective Studies; Thiopental

Topics: Adult; Alpha-Globulins; Anemia, Sickle Cell; Blood Proteins; Body Weight; Female; Hemoglobins; Humans; Male; Protein Binding; Reflex; Serum Albumin; Thiopental; Time Factors

Topics: Amphibians; Anesthesia; Anesthesia, Conduction; Anesthesia, General; Animals; Animals, Laboratory; Anura; Atropine; Body Weight; Cardiac Output; Cats; Chloralose; Dogs; Fishes; Guinea Pigs; Haplorhini; Heart Rate; Hypnotics and Sedatives; Ketamine; Methods; Mice; Pentobarbital; Phencyclidine; Preanesthetic Medication; Rabbits; Rats; Reptiles; Thiopental

Topics: Air; Anesthesia, General; Apnea; Body Weight; Carbon Dioxide; Chemoreceptor Cells; Hemoglobins; Humans; Oxygen; Partial Pressure; Reflex; Thiopental; Time Factors

Topics: Animals; Biological Transport; Biotransformation; Body Weight; Chlorides; Cytarabine; Dialysis; Diffusion; Humans; Kinetics; Mammals; Methotrexate; Models, Biological; Organ Specificity; Pharmaceutical Preparations; Pharmacology; Species Specificity; Thermodynamics; Thiopental; Time Factors

Topics: Anesthesia, General; Animals; Antipyrine; Body Weight; Brain; Carbon Isotopes; Female; Gills; Half-Life; Kinetics; Liver; Male; Muscles; Pentobarbital; Sharks; Thiopental

Topics: Anesthesia, General; Benperidol; Bipolar Disorder; Body Weight; Electroconvulsive Therapy; Female; Humans; Male; Methohexital; Preanesthetic Medication; Propanidid; Schizophrenia; Thiopental; Time Factors

Topics: Adolescent; Adult; Aged; Anesthesia, General; Apnea; Body Weight; Female; Halothane; Humans; Intubation; Intubation, Intratracheal; Larynx; Liver Function Tests; Male; Meperidine; Methoxyflurane; Middle Aged; Neuromuscular Depolarizing Agents; Nitrous Oxide; Obesity; Oxygen; Pharynx; Succinylcholine; Thiopental; Time Factors

Topics: Adult; Androstanes; Anesthesia; Atropine; Blood Pressure; Body Weight; Female; Heart Rate; Humans; Injections; Isonipecotic Acids; Male; Meperidine; Middle Aged; Neostigmine; Neuromuscular Nondepolarizing Agents; Pancuronium; Succinylcholine; Synaptic Transmission; Thiopental

Topics: Adjuvants, Anesthesia; Anesthesia, General; Anesthesia, Intravenous; Animals; Barbiturates; Body Weight; Drug Synergism; Glucose; Guaifenesin; Horses; Narcotics; Preanesthetic Medication; Preoperative Care; Thiopental; Tranquilizing Agents

Topics: Animals; Body Weight; Drinking Behavior; Drug Tolerance; Female; Liver; Mortality; Rats; Sleep; Thiopental; Time Factors; Urine; Water

Topics: Administration, Oral; Amino Acid Oxidoreductases; Amobarbital; Animals; Barbiturates; Body Weight; Injections, Intraperitoneal; Levulinic Acids; Liver; Male; Organ Size; Pentobarbital; Phenobarbital; Porphyrins; Rats; Thiopental; Time Factors

Topics: Analgesics; Animals; Antitussive Agents; Body Weight; Cardiovascular System; Constriction; Digestive System; Drug Synergism; Drug Tolerance; Humans; Hypotension; Male; Meperidine; Methods; Mice; Morphine; Nalorphine; Piperidines; Pupil; Rats; Respiration; Substance-Related Disorders; Thiopental

Topics: Analgesics; Anesthetics, Local; Animals; Anti-Inflammatory Agents; Antitussive Agents; Blood Pressure; Body Weight; Cats; Central Nervous System; Cerebral Cortex; Codeine; Constipation; Dogs; Electrocardiography; Electroencephalography; Female; Guinea Pigs; Heart; Heart Rate; Histamine H1 Antagonists; In Vitro Techniques; Male; Mice; Morphinans; Nalorphine; Pentobarbital; Pentylenetetrazole; Rabbits; Rats; Respiration; Stimulation, Chemical; Thiopental; Time Factors

Topics: Adolescent; Adult; Age Factors; Aged; Anesthesia, Intravenous; Blood Pressure; Body Weight; Child; Drug Synergism; Female; Humans; Male; Middle Aged; Propanidid; Sex Factors; Succinylcholine; Thiopental; Time Factors; Tubocurarine

Topics: Adult; Age Factors; Aged; Anesthesia, Intravenous; Body Weight; Drug Tolerance; Humans; Thiopental; Time Factors

Topics: Amobarbital; Animals; Barbiturates; Basal Metabolism; Body Temperature; Body Weight; Hexobarbital; Hyperthyroidism; Hypothyroidism; Male; Pentobarbital; Phenobarbital; Rats; Thiopental; Thyroidectomy; Triiodothyronine; Zoxazolamine

Topics: Adipose Tissue; Adolescent; Adult; Aged; Anesthesia, Inhalation; Body Surface Area; Body Weight; Conditioning, Eyelid; Female; Humans; Male; Middle Aged; Somatotypes; Statistics as Topic; Thiopental

Topics: Anesthesia, Inhalation; Anesthesia, Intravenous; Animals; Benperidol; Blood Pressure; Blood Volume; Body Weight; Cardiac Output; Cardiac Volume; Dogs; Fentanyl; Gold Colloid, Radioactive; Halothane; Hematocrit; Liver Circulation; Mathematics; Neuroleptanalgesia; Plasma Volume; Pulse; Radionuclide Imaging; Regional Blood Flow; Serum Albumin, Radio-Iodinated; Thiopental

Topics: Anesthesia, General; Blood Pressure Determination; Body Height; Body Weight; Fentanyl; Halothane; Humans; Methoxyflurane; Nitrous Oxide; Obesity; Posture; Preanesthetic Medication; Thiopental; Time Factors

Topics: Analysis of Variance; Anesthesia, Inhalation; Blood Gas Analysis; Body Weight; Carbon Dioxide; Female; Gallamine Triethiodide; Halothane; Humans; Male; Mathematics; Models, Theoretical; Oxygen; Oxygen Consumption; Thiopental; Ventilation-Perfusion Ratio

Topics: Anesthesia, Intravenous; Animals; Body Weight; Male; Rats; Statistics as Topic; Thiopental

Topics: Animals; Body Weight; Female; Fetus; Maternal-Fetal Exchange; Mice; Pregnancy; Pregnancy, Animal; Thiopental

Topics: Adult; Age Factors; Animals; Body Weight; Cats; Depression; Female; Galvanic Skin Response; Humans; Injections, Intravenous; Male; Methods; Middle Aged; Neurotic Disorders; Psychotic Disorders; Sex Factors; Sodium; Thiopental

Topics: Animals; Blood Pressure; Body Weight; Carotid Arteries; Creatinine; Dogs; Glomerular Filtration Rate; Heart Rate; Kidney; Kidney Transplantation; Natriuresis; Neck; Osmolar Concentration; Potassium; Renal Artery; Thiopental; Transplantation, Homologous; Urea; Urine; Water-Electrolyte Balance

Topics: Adipose Tissue; Age Factors; Anesthesia; Animals; Barbiturates; Body Weight; Female; Hexobarbital; Male; Rats; Sex Factors; Statistics as Topic; Thiopental; Time Factors

Topics: Age Factors; Anesthesia, Intravenous; Anesthesia, Rectal; Body Weight; Child; Child, Preschool; Humans; Thiopental; Tonsillectomy

Topics: Aging; Barbiturates; Body Weight; Body Weights and Measures; Humans; Thiopental