[Comparison of the endocrine response to the stress caused by 2 anesthesiologic techniques: inhalation and intravenous anesthesia].
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Adult↗
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Results for “Anesthesia, Inhalation”
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Comparative study between the effects of total intravenous anesthesia with propofol and balanced anesthesia with halothane on the alveolar-arterial oxygen tension difference and on the pulmonary shunt.
Inhalation anesthesia with halothane, inhibiting hypoxic pulmonary vasoconstriction, causes an increase in intrapulmonary shunt development as well as an increase of alveolar-arterial oxygen tension difference. In contrast, total intravenous anesthesia with propofol, as with other intravenous anesthetics, should not alter pulmonary gas exchange. The present study was carried out using two groups of patients of similar age, sex and weight, who were subjected to neurosurgical procedures. One group was under general inhalational anesthesia with halothane and the other group under total intravenous anesthesia with propofol. In a simple clinical manner and applying established formulae, the determination of intrapulmonary shunt and alveolar-arterial oxygen tension difference showed a significant increase after 120 min in the halothane group, whereas the group that received propofol did not show any significant variation. We therefore conclude that propofol, different from halothane, does not affect the pulmonary gas exchange.
Adult↗
[The pharmacokinetic study of desflurane, sevoflurane, isoflurane and enflurane in general anesthesia].
OBJECTIVE: To compare pharmacokinetics of desflurane, sevoflurane, isoflurane and enflurane in general anesthesia. METHODS: 40 patients scheduled for abdominal hysterectomy under general anesthesia were randomly divided into desflurane(D), sevoflurane(S), isofluane(I) and enflurane(E) groups. After induction of anesthesia and endotracheal intubation, desired fraction (Fd) of desflurane(6%), sevoflurane(2%), isoflurane (1.15%) and enflurane(1.7%) in oxygen and nitrous oxide(1:2) were inhaled in D, S, I and E groups, respectively. The fractional end tidal alveolar concentration (Fa) was adjusted to 1MAC during the maintenance of anesthsia. Fa and the fractional inspired concentration of inhaled anesthetics (Fi) were monitored continuously. During operation, fentanyl was infused continuously and pancuronium was injected intermittently. RESULTS: After the beginning of inhalational anesthesia, the time required for Fa/Fi = 1:2 and Fa = 1MAC in D and S groups was significantly shorter than that in E and I groups. The rates of Fa/Fi in D and S groups were significantly higher than those in E and I groups during the maintenance of anesthesia, so were those of Fa/Fd. After cessation of inhalational anesthesia, the time required for Fa equaled to 50% of Fa0(the last Fa during stoping administration of the inhalational anesthesia) in D group was significantly faster than that in the other three groups. CONCLUSIONS: The rates of desflurane wash-in and wash-out are faster than those of other inhaled anesthetics. The depth of anesthesia is easy to control when desflurane is used in general anesthesia.
Anesthesia, General↗
[Apneic anesthesia for microsurgery of the larynx under propofol anesthesia].
Apneic anesthesia with intermittent ventilation (AAIV) under inhalational anesthesia has been reported to improve visualization of the larynx with lack of vocal cord motion in laryngeal microsurgery. In this study, we evaluated AAIV using total intravenous anesthesia with propofol and fentanyl instead of inhalational anesthesia in 11 patients undergoing microsurgery of the larynx, and examined the effects of AAIV on respiration and circulation. Anesthesia was maintained with infusion of propofol 4-10 mg.kg-1.h-1 and intermittent administration of fentanyl and vecuronium intravenously. The lungs were ventilated with 100% oxygen, and the endotracheal tube was removed during the apneic period. AAIV provided the otorhinolaryngologist sufficient room in which to operate and an immobile field without complications in any of the patients. The number of periods of apnea (mean +/- SD) was 3.3 +/- 1.3, and the duration of apnea was 292 +/- 23 seconds. Neither blood pressure nor heart rate changed during the apneic periods. Arterial oxygen saturation measured using pulse oxymetry (Spo2) changed in none of the patients except an obese patient whose Spo2 declined to 90%. End-tidal carbon dioxide level increased for 14.9 mmHg immediately after apneic periods. Propofol vielded stable and adequate levels of anesthesia during apneic periods. We conclude that AAIV using constant monitoring of Spo2 is a useful and safe technique, and that propofol is a suitable anesthetic agent for AAIV.
Anesthesia, Intravenous↗
Anesthetics change tissue proton NMR relaxation.
Previous studies have shown the treatment of experimental animals with therapeutic doses of pharmaceuticals in acute and chronic regimens has resulted in extensive (up to 33%) change in tissue proton NMR relaxation times. In this study, the effects of injectable anesthetics (Innovar, pentobarbital, ketamine and alpha-chloralose) were compared with inhalational anesthetics (halothane, enflurane and isoflurane). Proton NMR T1 and T2 relaxation times were obtained from excised tissues of anesthetized rats (6 each treatment). Sodium pentobarbital and alpha-chloralose showed no alterations, whereas Innovar produced increases in brain and kidney relaxation times and ketamine showed increases in the heart. More widespread and extensive changes were observed after 1.5 hours of inhalation anesthesia: liver, muscle and fat showed relaxation time decrease; heart, spleen and lung were increased. No change in water content, as measured by wet/dry ratios, was observed for any tissue. Therefore, intravenous anesthesia may be preferred to inhalational anesthesia for magnetic resonance imaging based on potential changes in tissue relaxation properties. In addition, the absence of a measurable effect on brain suggests that the mechanism for anesthesia does not involve major changes in brain water.
Anesthetics↗
The rate of CSF formation, resistance to reabsorption of CSF, and aperiodic analysis of the EEG following administration of flumazenil to dogs.
The effects of flumazenil, a benzodiazepine antagonist, on the rate of cerebrospinal fluid (CSF) formation (Vf), resistance to reabsorption of CSF (Ra) and the electroencephalogram (EEG) was determined in 12 dogs anesthetized with halothane (0.4%, end-expired) and nitrous oxide (66%, inspired) in oxygen. In six dogs the responses to flumazenil were measured during administration of midazolam (1.6 mg/kg followed by 1.25 mg.kg-1.h-1, intravenously) given along with inhalational anesthesia, whereas in the other six dogs the responses to flumazenil were measured during inhalational anesthesia without midazolam. Vf and Ra were determined using ventriculocisternal perfusion, and EEG activity was evaluated using aperiodic analysis. Flumazenil, 0.0025 and 0.16 mg/kg, was administered both when CSF pressure was normal and when CSF pressure was increased to 36-38 cmH2O by continuous infusion of mock CSF. Flumazenil produced no statistically significant change in Vf. Flumazenil did produce inconsistent and relatively small changes in Ra. Quantitative aperiodic analysis indicated changes in EEG activity only when the larger dose of flumazenil was given to dogs receiving midazolam. At normal CSF pressure the changes were consistent and were comprised of decreases in theta, alpha, and total hemispheric power. At elevated CSF pressure the changes were less consistent. It is concluded that smaller doses of flumazenil (which cause no EEG changes with the present method of analysis) and larger doses of flumazenil (which reverse midazolam-induced increase of theta and alpha activity) produce no change of Vf and no consistent change of Ra. Although flumazenil given in the presence of midazolam may increase Ra, thereby increasing CSF pressure and impairing contraction of CSF volume, this effect is not likely to be clinically important.
Anesthesia, Inhalation↗
Gas Man--an example of goal oriented computer-assisted teaching which results in learning.
Gas Man is an educational computer simulation program. The goal of the program is for the user to learn the theory and application of inhalation anesthesia uptake and distribution. The program and accompanying text are designed to be used by medical students, pharmacy students, anesthesia residents, nurses, practicing anesthesiologists, and medical equipment technicians and engineers. After using the program, the learner should understand the time course of patient response to inhalation anesthesia. He should know the factors which influence patient response and be able to predict their impact in specific situations. The key to Gas Man's success are: A well-defined and valid educational goal, teaching anesthesia uptake and distribution. An identifiable and testable set of educational objectives. A specific set of learner tasks to achieve those objectives, the actual simulation exercises. The appropriate educational medium, computer simulation and graphics. Effective software implementation, the Gas Man Program.
Anesthesia, Inhalation↗
Development of a neurosurgical operating table for adult cattle and changes in intracranial pressure and blood pressure in adult cattle undergoing long-time isoflurane anesthesia.
We developed a neurosurgical operating table for restraining adult cattle in the sternal recumbent position during long-time inhalation anesthesia, and examined intracranial pressure (ICP), blood pressure and blood gases during isoflurane anesthesia. We confirmed that the maintenance of inhalation anesthesia, the restraint of cattle in the sternal recumbent position and bringing the cattle out of anesthesia could all be carried out safely using the operating table we produced. For the purposes of the present experiment, the cattle were divided into 2 groups: the SR group, which underwent sternal recumbency for 8 hr under isoflurane anesthesia using the neurosurgical operating table, and the RR group, which underwent right lateral recumbency for 3 hr under isoflurane anesthesia on a standard operating table. The mean ICP was found to be significantly lower in the SR group than in the RR group during anesthesia, and PaO2 was significantly higher in the SR group. In the SR group, no complications such as regurgitation or ruminal tympany occurred for 8 hr after the induction of anesthesia, and recovery from anesthesia was uneventful. In contrast, all RR cattle showed ruminal tympany and regurgitated ruminal fluid at 3 hr after the induction of anesthesia. Thus, the neurosurgical operating table developed in the present study may be useful for long-time anesthesia and neurosurgery of adult cattle.
Aging↗
[Temperature of the gases in circuit during general anesthesia for inhalation with low flow of fresh gases].
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Adult↗
Anesthesia and pediatric endoscopy.
An inhalation anesthetic technique applicable to all kinds of endoscopy in children is described. It provides maximum visualization for the endoscopist, permits pressurization of the airway, does not require exceptional or unusual skills, and can be successfully managed by an anesthetist utilizing universally recognized techniques of inhalation anesthesia.
Anesthesia, Inhalation↗
Hearing impairment caused by intratympanic pressure changes during general anesthesia.
Hearing impairment is not often considered a potential complication of general anesthesia; however, four patients who sustained hearing loss following nitrous oxide inhalation anesthesia have recently come to the authors' attention. The cases are presented and middle ear pressure measurements taken during endotracheal inhalation anesthesia with various agents are reported. Factors predisposing to hearing loss during anesthesia are discussed.
Adult↗
Extent and localization of changes in upper airway caliber with varying concentrations of sevoflurane in children.
BACKGROUND: Previous studies in humans suggest that inhibition of upper airway muscle activity is independent of the dose of inhalational anesthesia. Whether a dose-independent relation applies to changes in airway caliber is unknown. The authors sought to evaluate the configurational changes that lead to upper airway narrowing during inhalational anesthesia with sevoflurane and to determine whether these changes are dose dependent within a clinically relevant dose range. METHODS: Fifteen children undergoing elective magnetic resonance imaging of the brain were studied. Magnetic resonance images of the upper airway were acquired at sevoflurane concentrations of 0.5, 1.0, and 1.5 minimum alveolar concentration (MAC), administered in random sequence. At least 15 min was allowed for equilibration of inspired and alveolar partial pressures of sevoflurane. Images were acquired in early expiration at the level of the soft palate, base of the tongue, and tip of the epiglottis. Airway cross-sectional area (CSA), anteroposterior, and transverse dimension were determined using image-analysis software. RESULTS: At each anatomical level, pharyngeal CSA decreased progressively with increasing depth of sevoflurane anesthesia (P < 0.001). Increasing the sevoflurane concentration from 0.5 to 1.0 MAC reduced airway CSA by 13-18%, and a further increase to 1.5 MAC resulted in an overall 28-34% reduction in CSA. The reduction in CSA was predominantly due to a decrease in anteroposterior dimension. CONCLUSIONS: Increasing the depth of sevoflurane anesthesia resulted in a relatively uniform reduction in pharyngeal caliber at each anatomical level studied. The effect of sevoflurane on upper airway caliber is dose dependent.
Anesthesia, Inhalation↗
Anesthesia for neurovascular embolisation from 1997-1999 in Prasat Neurological Institute.
BACKGROUND: Embolisation is another treatment of choice in neurovascular abnormalities. We reported anesthetic data as a basis for further research. METHOD: A descriptive retrospective study was performed to evaluate the techniques, drug usage and complications associated with anesthesia in patients who underwent embolisation in the Prasat Neurological Institute within 3 years. RESULTS: There were 108 cases and 213 procedures. The diagnoses were mainly arteriovenous malformation (56.34%) and carotid cavernous sinus fistula (23%). 74.65 per cent received general anesthesia with endotracheal tube, 11.74 per cent received inhalation anesthesia with laryngeal mask airway, 7.04 per cent received inhalation anesthesia with endotracheal tube and 6.57 per cent received total intravenous anesthesia with laryngeal mask airway. The patients were given anesthesia with thiopental (73.24%), propofol (26.76%) intubated with succinyl choline (69.01%), nondepolarizing muscle relaxant (21.13%) and without any muscle relaxant (9.86%) maintained with oxygen and halothane (63.85%), isoflurane (4.23%) and sevoflurane (25.35%). Fentanyl (87.79%), morphine (1.88%), nalbunorphine (0.47%) were given as narcotics and if a muscle relaxant was required, atracurium (64.79%), pancuronium (5.63%), vecuronium (4.23%) were used. The complications were hypotension (7.04%), anaphylaxis (1.88%), arterial vasospasm (0.47%) and hyperglycemia (1.41%). However, there was no significant statistical difference among the anesthetic techniques and those complications. Post-anesthetic complications within 30 minutes included shivering (3.76%) which was statistically related to the duration of the procedure. CONCLUSION: It was concluded that in neurovascular embolisation, there was no need for special techniques or drugs in anesthesia but anesthetic personnel had to optimize the patient's condition for the safety and convenience of neuroradiologists and there should be an awareness of complications eventhough these were not related to anesthetic techniques; further improvement in prevention should be established.
Adolescent↗
Use of tympanostomy tubes in otitis media.
Tympanostomy tubes (TT) are frequently employed as treatment for otitis media (OM) although there is little-clinical or experimental evidence of their efficacy. Potential detriments of TT include cost, risk of inhalation anesthesia, intraoperative complications, and tympanic membrane (TM) damage. Potential benefits include elimination of the conductive hearing loss (CHL), reduction in the occurrence of acute purulent OM, and avoidance of sequelae. The cost/benefit ratio of TT has never been accurately determined and morbid complications of inhalation anesthesia and the surgical procedure appear to be rate. There is evidence that TT significantly reduce the CHL of OM as well as reduce the incidence of recurrent acute purulent OM and help avoid sequelae. It is therefore determined that the risk of TT insertion for middle ear effusion (occasional TM changes) can be justified, in properly selected patients, by the benefits (immediate improvement in hearing and reduction in the incidence of recurrent acute purulent OM).
Anesthesia, Inhalation↗
Change of inhalation anesthetic agents for management of ventricular premature depolarizations in anesthetized cats and dogs.
Ventricular premature depolarizations (VPD) were found in 27 cats and 14 dogs during inhalation anesthesia. For animals receiving halothane, the anesthetic agent was changed to enflurane (n = 22) or isoflurane (n = 15). After the change to enflurane, the VPD reverted to normal sinus rhythm (n = 19) or decreased in frequency (n = 3). After the change to isoflurane, the VPD reverted to normal sinus rhythm (n = 14) or decreased in frequency (n = 1). For 4 cats receiving enflurane, the inhalant agent was changed to halothane, which caused an increased frequency of VPD (n = 3) or reversion to normal sinus rhythm (n = 1). It was concluded that cats and dogs with VPD during inhalation anesthesia with halothane would benefit from a change to enflurane or isoflurane.
Anesthesia, Inhalation↗
[Effects of anesthesia with inhalation anesthetics on excitation, conduction and refractory parameters of the heart. Experiments in dogs].
Cardiac excitation, conduction, and refractory parameters of the heart were investigated in 40 beagle dogs to obtain basic values under the influence of the following 9 inhalation anaesthetic regimes using HIS-bundle electrography and programmed stimulation: 1. halothane; 2. enflurane; 3. isoflurane; 4. halothane+nitrous oxide; 4. enflurane+nitrous oxide; 6. isoflurane+nitrous oxide; 7. alfentanil/midazolam/succinylcholine+nitrous oxide; 8. fentanyl/midazolam/pancuronium bromide+nitrous oxide; 9. propofol+nitrous oxide. It could be shown that inhalation anaesthetics under laboratory conditions exert some influences on the observed cardiac parameters, although they are not as strong as those of intravenous anaesthetics. Therefore their effects should be considered in experiments with other substances or in cardiovascular results.
Anesthesia, Inhalation↗
A nonrebreathing valve for use in inhalation therapy and anesthesia in the adult.
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Anesthesia↗
[Total intravenous anesthesia with propofol and fentanyl for laparoscopic cholecystectomy].
The postoperative antiemetic effect of total intravenous anesthesia with propofol and fentanyl was evaluated in 40 patients for laparoscopic cholecystectomy. Patients were divided into 2 groups. In group P, anesthesia was induced with intravenous fentanyl 0.1 mg and propofol 2 mg.kg-1 and maintained with continuous infusion of propofol. In group I, anesthesia was induced with intravenous thiopental 5 mg.kg-1 and maintained with nitrous oxide 60% in oxygen and isoflurane. Post-operative nausea and vomiting were recorded for 8 h after surgery. Nausea scores (range 1-4) were significantly lower in group P as compared with group I at 0 h after surgery, but no difference between the groups at 2 h, 4 h, 8 h after surgery. No significant differences were found in the incidence of vomiting between the groups. These results suggest that total intravenous anesthesia with propofol and fentanyl is superior to inhalational anesthesia with nitrous oxide and isoflurane in postoperative nausea. This antiemetic effect is, however, limited in the early period after anesthesia.
Aged↗