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PubMed1994

The effects of total intravenous anesthesia using propofol, ketamine, and vecuronium on cardiovascular response and wake up time.

Total intravenous anesthesia (TIVA) can be an effective alternative to inhalational anesthesia. Various techniques of TIVA have been associated with significant cardiovascular alterations and prolonged wake up times. The purpose of this study was to determine if TIVA utilizing propofol, ketamine, and vecuronium would provide stable hemodynamics in normotensive ASA physical status I and II patients and allow rapid awakening upon completion of surgery. Anesthesia was induced with propofol 1.0 mg/kg intravenously (IV), followed immediately by ketamine 1.0 mg/kg IV and vecuronium 0.1 mg/kg IV. Anesthesia was maintained by constant infusion of propofol 100-200 micrograms/kg/min and ketamine 17-34 micrograms/kg/min. This combination maintained hemodynamic stability and provided a rapid wake up time in 80% of the 40 subjects. The remaining 20% experienced significant tachycardia and hypertension or premature ventricular contractions. The mean wake up time was 9.7 minutes from time of neuromuscular blocking reversal to time of extubation. TIVA can be accomplished with propofol, ketamine, and vecuronium; however, 20% of patients experienced side effects, which make this method less attractive compared to alternative anesthetic techniques.

Adolescent↗
PubMed1998

[Body temperature changes during combined inhalational and epidural anesthesia].

We investigated the effects of combined inhalational and lumbar epidural anesthesia on body temperature in 8 women for long-lasting lower abdominal surgery. Probes for forehead deep temperature and skin-surface temperatures were placed on the forehead, forearm, fingertip and toe tip on patients' arrival at the operating room. Tympanic membrane temperature was also measured. Lumbar epidural block was established with 2% lidocaine 10 ml. Twenty minutes later, general anesthesia was induced and maintained with nitrous oxide-oxygen-isoflurane. Epidural anesthesia was maintained with intermittent dose of 1% mepivacaine. Before the end of surgery, isoflurane concentration was increased from about 0.5% to 2% and was maintained at this level for 20 minutes, after which it was reduced. With the establishment of epidural blockade, toe tip temperature increased and fingertip temperature decreased, while core temperature remained unchanged. After induction of general anesthesia, fingertip temperature increased, while core temperature decreased. The core temperature drop during the anesthetic induction was significantly affected by the increase in toe tip temperature. Before the end of surgery, core temperature remained at a reduced but constant level, while fingertip temperature continued to decrease. With the application of 2% isoflurane, fingertip temperature increased, while core temperature decreased. The core temperature drop was significantly affected by the increase in fingertip temperature. After the reduction of isoflurane concentration, these temperature changes were reversed fully. At the end of surgery, fingertip temperature decreased, while core temperature increased. During mild hypothermia, isoflurane depressed thermoregulatory vasoconstriction dose-dependently until its concentration reached 0.6-0.7%. In conclusion, anesthetics-induced redistribution of body heat significantly affects the core temperature throughout anesthesia. Peripheral hypothermia results in core temperature drop when the redistribution is induced by anesthetics. Thermoregulatory vasoconstriction may not only suppress heat loss but also increase core temperature through centralization of body heat.

Adult↗
PubMed1982

[The history of anesthesia apparatus: basic principles].

The beginnings of modern anesthetic equipment date back to Morton's inhalation flagon in 1846. The numerous devices developed and introduced subsequently can be divided into four groups: 1. Simple ether and chloroform masks for open inhalation anesthesia, from Simpson (1847) to Brown (1928). 2. Vapour inhalators according to the "draw over" principle of Snow (1847) up to the Oxford vaporizer (1941). 3. Closed or half-closed inhalation equipment for ether or chloroform with to and fro breathing, from Clover (1877) to Ombredanne (1908). 4. Equipment for anaesthesia with nitrous oxide. From 1868 onwards this led to the incorporation of gas bottles in anaesthetic equipment and between 1885 and 1890 to the construction of mixing-valves for nitrous oxide and oxygen. In addition, reducing valves, flow meters and vaporizers were developed. The first anaesthetic apparatus with circle system and CO2-absorber was constructed in 1925 by the Dräger factory in Lübeck. Sudeck and Schmidt introduced this technique of anaesthesia in the university hospital of Hamburg-Eppendorf between 1920 and 1925.

Anesthesiology↗
PubMed1998

Cardiorespiratory effects of sevoflurane, isoflurane, and halothane anesthesia in horses.

OBJECTIVE: To determine and compare cardiorespiratory and recovery effects of sevoflurane, isoflurane, and halothane in horses. ANIMALS: 8 clinically normal horses (4 mares, 4 geldings), 5 to 12 years old. PROCEDURE: Inhalation anesthesia was maintained for 90 minutes with sevoflurane, isoflurane, or halothane. Anesthesia depth was maintained at 1.5 minimum alveolar concentration of halothane, isoflurane, and sevoflurane, then was reduced at 30 and 60 minutes. A surgical plane of anesthesia was reinduced by administration of ketamine or thiopental or by increasing the fractional inspired concentration of sevoflurane. Cardiovascular and pulmonary variables were recorded and compared among inhalation anesthetics. Recovery was monitored, and subjective assessment of recovery quality was performed. RESULTS: Hemodynamic and pulmonary indices during sevoflurane anesthesia were similar to those of isoflurane. Cardiac output and systemic arterial pressure decreased less during sevoflurane and isoflurane anesthesia than during halothane anesthesia. After 90 minutes, cardiac output was greater for sevoflurane and isoflurane, respectively, compared with halothane. Mean arterial pressure was similar for all three anesthetic agents. Respiratory rate for sevoflurane and isoflurane was less than that for halothane. This apparent respiratory depression correlated with greater increase in PaCO2 and decreased pH when sevoflurane and isoflurane were compared with halothane. Recovery from sevoflurane anesthesia was qualitatively similar and superior to recovery from isoflurane and halothane, respectively. Time to standing did not differ significantly between sevoflurane and isoflurane, but was shorter than halothane. CONCLUSIONS: Sevoflurane induced cardiorespiratory effects that were comparable to those of isoflurane and halothane. Cardiac output was greater and respiratory rate was less than that for halothane at 1.5 MAC. Sevoflurane anesthesia was characterized by good control of anesthesia depth during induction, maintenance, and recovery. Recovery time after sevoflurane anesthesia was comparable to that for isoflurane, and recovery was smooth and controlled in a manner consistent with recovery from halothane.

Anesthesia, Inhalation↗
PubMed1984

Absence of electroencephalographic excitation pattern under isoflurane anesthesia.

In twelve patients the EEG was recorded under isoflurane--nitrous oxide inhalation anesthesia. A quiet EEG pattern was registered, without suppressions and seizures of spike activity which are often observed under enflurane. This was the case even when end expiratory CO2 shifted to low values (3-3.6 Vol%). In one patient the induction with N2O/O2 and thiopentone, resulted in spikes and suppression bursts on the EEG. After isoflurane was added, these changes disappeared. In another patient, epileptic EEG patterns were observed prior to the induction (confirmed by the history of the patient). During isoflurane anesthesia the epileptic waves disappeared and remained absent.

Adult↗
PubMed1991

[Initial washout time of inhaled anesthetic agents].

Recovery of inhalation anesthesia is generally considered the inverse of induction. While other factors remain unchanged, the rate of elimination of an inhaled anesthetic agent with a lower solubility such as nitrous oxide (N2O) is faster than one with a high solubility. Therefore, at the end of surgery it is a common practice to discontinue the volatile agent prior to discontinuing N2O. However, the results of our routine monitoring of end-tidal concentrations of anesthetics and physiological gases by employing a mass spectrometer lead us to question the practice. We studied 24 non-premedicated ASA I/II patients requiring endotracheal intubation with an anesthesia time over 2 h. All patients were mechanically ventilated at an appropriate tidal volume and respiratory rate to maintain an ETCO2 of 35-38 mmHg with an anesthetic mixture of 40% O2 and 60% N2O and isoflurane (Forane). At the end of surgery, both N2O and isoflurane were discontinued simultaneously and total oxygen flow was increased to 6 or 10 l/min by random. The exhaled partial pressure of both inhaled anesthetic agents were assessed at the time of anesthetic termination, after 1, 2 min, and then every 2 min up to 20 min or at the time of extubation. The results obtained were plotted against real time using two different scales. Despite the marked difference in their plasma solubilities, these two inhaled anesthetic agents reached to low exhaled partial pressure that had no clinical significance about ten minutes after discontinuation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2001

A survey on anesthesia for thoracoscopic sympathetic surgery in treatment of hyperhidrosis palmaris in Taiwan.

Thoracoscopic approach to sympathetic surgery has gained its popularity and emerged as the main stream in the treatment of hyperhidrosis palmaris in Taiwan. Different kinds of anesthesia have been practiced and reported in these surgeries. We made a survey of anesthetic methods in twelve medical centers and regional hospitals of the island. It was found out that the choice of the anesthesia was mainly dependent on the mutual trust and the full communication between the anesthesiologist and the surgeon, both based on their skills and the operative methods chosen by the surgeon. Single-lumen endotracheal tube with general inhalation anesthesia is practiced in most of the hospitals surveyed. Sevoflurane and desflurane are the choices of the inhalational anesthetic agents. In short, the anesthesiologists tend to practice the type of anesthesia that is simple but safe enough to secure the airway of the patient throughout the thoracoscopic sympathetic surgery.

Anesthesia↗
PubMed2006

[Induced hypothermia during low-flow anesthesia in elderly patients].

The purpose of the study was to investigate the possibility of reducing of level of induced hypothermia during general balanced anesthesia, by using of low - flow techniques of anesthesia in elderly and senile patients. The temperature homeostasis was studied intraoperatively in 76 patients, aged 65-84 years, ASA III - IV, underwent different surgical operations under high (n=34) and low - flow (n=42) anesthesia. It was demonstrated that the low - flow anesthesia allows not only reduce loss of moisture and heat from the patients airway during surgery, but also optimize the intraoperative patient - body temperature, decrease level of induced hypothermia and minimize frequency of complication due to temperature misbalance in the immediate postoperative period. Such anesthesia is a sufficiently effective and safe method of inhalation anesthesia, which can be used with good results in routine geriatric surgery.

Aged↗
PubMed1999

Decreased respiratory depression during emergence from anesthesia with sevoflurane/N2O than with sevoflurane alone.

PURPOSE: To investigate ventilation and gas elimination during the emergence from inhalational anesthesia with controlled normoventilation with either sevoflurane/N2O or sevoflurane alone. METHODS: Twenty-four ASA I-II patients scheduled for abdominal hysterectomy were randomly allocated to receive either 1.3 MAC sevoflurane/N2O (n = 12) or equi-MAC sevoflurane (n = 12) in 30% oxygen (O2). Expired minute ventilation volumes (V(E)), end-tidal (ET) concentrations of O2, carbon dioxide (CO2), sevoflurane and N2O as well as pulse oximetry saturation (SpO2) and CO2 elimination rates (VCO2) were measured. The ET concentrations of sevoflurane and N2O were converted to total MAC values and gas elimination was expressed in terms of MAC reduction. Time to resumption of spontaneous breathing and extubation were recorded and arterial blood gas analysis was performed at the end of controlled normoventilation and at the beginning of spontaneous breathing. RESULTS: Resumption of spontaneous breathing and extubation were 8 and 13 min less, respectively, in the sevoflurane/N2O than in the sevoflurane group. Spontaneous breathing was resumed in both groups when pH had decreased by 0.07-0.08 and PaCO2 increased by 1.3-1.5 kPa. Depression of V(E) and VCO2 were less, and MAC reduction more rapid in the sevoflurane/N2O than in the sevoflurane group. CONCLUSIONS: Respiratory recovery was faster after sevoflurane/N2O than sevoflurane anesthesia. Changes in pH and PaCO2 rather than absolute values were important for resumption of spontaneous breathing after controlled normoventilation. In both groups, the tracheas were extubated at about 0.2 MAC.

Adult↗
PubMed1981

Bilateral vocal cord paralysis following general anesthesia.

A rare case of bilateral vocal cord paralysis after orotracheal intubation and inhalation anesthesia, in surgery not in relation to the neck, is presented. There was no obvious cause for the paralysis and possible etiological factors are discussed. Overextension of the neck during intubation is suspected of being the etiological agent causing stretching of both the vagus nerves. Normal laryngeal function returned after two months.

Adolescent↗
PubMed2005

Susceptibility of rats to corneal lesions after injectable anesthesia.

Corneal injury is not a commonly reported side effect after injectable or inhalation anesthesia in rats, but a number of surgery studies at our facility resulted in a high incidence of these injuries. To explore the potential association of various anesthetic protocols with the development of corneal lesions in rats, we retrospectively evaluated clinical records and sections of eyes from 215 male and 187 female Wistar rats used in eight intravenous infusion toxicology studies. None of the studied compounds was associated with eye toxicity. For placement of jugular vein vascular access ports, rats were anesthetized with enflurane, isoflurane, ketamine-xylazine, or Hypnorm-midazolam. Histologically, corneal changes were scored from 0 to 4 in light of degree of mineralization, leukocytic infiltrates, neovascularization, fibrosis, and ulceration. Prestudy (postsurgical) ophthalmic examination findings of corneal opacities were correlated with mineralization of the anterior limiting membrane and corneal ulceration. Corneal lesions were more severe in animals anesthetized with ketamine-xylazine, and minimal changes occurred after anesthesia with either enflurane or isoflurane. The results of further analysis suggest that corneal lesions can be observed within 24 h after injectable anesthetic administration and are not reversible. The severity of corneal changes was reduced when ketamine-xylazine anesthesia was reversed with yohimbine. Compared with Sprague-Dawley and Lewis rats, Wistar, Long-Evans, and Fischer 344 rats had increased incidence and severity of corneal lesions after anesthesia with ketamine-xylazine, suggesting that these three strains are at increased risk for developing postanesthetic corneal lesions with this regimen.

Anesthesia, Intravenous↗
PubMed2001

Functional MRI as a tool to assess vision in dogs: the optimal anesthetic.

Functional magnetic resonance imaging (fMRI) is a recent advance in neuroimaging that provides a picture of brain activity with excellent spatial resolution. Current methods used to evaluate canine vision are poorly standardized and vulnerable to bias. Functional MRI may represent a valuable method of testing vision in dogs if the impacts of anesthesia on fMRI are understood. Six dogs were scanned during visual stimulation, each under three different anesthetic protocols (isoflurane, propofol, fentanyl/midazolam) to address the questions: (1) Can visually evoked fMR signals be reliably recorded in anesthetized dogs? and (2) Which anesthetic agent permits the least suppression of visually induced fMR signal in dogs? This study confirms that visual stimuli reliably elicit neural activity and fMR signal change in anesthetized dogs. No significant differences in images acquired under the three anesthetics were found, and there was no significant relationship between anesthetic dose and brain activity, within the range of doses used in this study. Images obtained during isoflurane anesthesia were more consistent between dogs than those obtained with the other two agents. This reduced variation may reflect the fact that inhalant anesthesia is more easily controlled than intravenous anesthesia under conditions associated with high field fMRI.

Anesthesia↗
PubMed1996

Sevoflurane versus isoflurane: induction and recovery characteristics with single-breath inhaled inductions of anesthesia.

Because of its nonpungent odor and low blood-gas solubility coefficient, sevoflurane might be an ideal drug for single-breath inhaled induction of anesthesia. Fifty ASA grade I-III ambulatory surgical patients (18-76 yr old) received a single-breath induction with either 5.0% sevoflurane or 5.0% isoflurane (randomized) in a 1:1 N2O/O2 mixture. Anesthesia was maintained with the same anesthetic in 70% N2O until the end of surgery, when anesthetics were abruptly discontinued. Induction times (loss of eyelash reflex) were similar for sevoflurane (75 +/- 3 s, mean +/- se) and isoflurane (67 +/- 4 s, P = not significant). Sevoflurane patients were less likely to have complications during induction (P < 0.005); coughing occurred more frequently with isoflurane (P < 0.001). During induction, heart rate increased with both sevoflurane (from 73 +/- 3 to 90 +/- 4 bpm, P < 0.05) and isoflurane (from 70 +/- 2 to 92 +/- 2 bpm, P < 0.05); the increase with isoflurane was greater than that with sevoflurane. Times to eye opening for sevoflurane (8.1 1 +/- 1.0 min) did not differ significantly from those for isoflurane (10.6 +/- 1.3 min). Patients opened their eyes at lower end-tidal minimum alveolar anesthetic concentration (MAC)-fractions of sevoflurane (0.12 +/- 0.01 MAC) than isoflurane (0.15 +/- 0.01 MAC, P < 0.01). During recovery, patients who received sevoflurane felt less clumsy (P < 0.001) and less confused (P < 0.005) but had higher pain scores (P < 0.005) than those who received isoflurane. Sevoflurane is more suitable than isoflurane for single-breath induction, because it produces a smoother induction with a lower incidence of complications and better patient acceptance.

Adolescent↗
PubMed2000

[Recovery of balanced anesthesia with various inhalation anesthetics in comparison to intravenous anesthetics: a retrospective analysis of 20,060 patients].

BACKGROUND: The aim of this investigation was to compare routine balanced anaesthesia with different inhalation agents to intravenous anaesthesia (IVA) using an Anaesthesia-Information-Management-System (AIMS) with regard to time of recovery from anaesthesia, the time of discharge from the postanaesthesia care unit (PACU) and postoperative nausea as well as postoperative therapy with analgesics. METHODS: In 1997 and 1998 all relevant data of each anaesthesia procedure have been recorded using the online documentation Software NarkoData. These data sets have been stored into a relational database during each anaesthesia procedure. For evaluation the information has been exported from the database to a statistics program via 'Structured Query Langvage' (SOL). Balanced anaesthesia has been performed using isoflurane, halothane, and sevoflurane, respectively, supplemented with or without nitrous Oxide (N2O). The intravenous based anaesthesia-groups included propofol-fentanyl or propofol-remifentanil. RESULTS: The fastest recovery was seen in patients of the isoflurane group (11.2 +/- 7.7 minutes), and the longest time for extubation was observed in patients wich halothane anaesthesia (12.8 +/- 9.3 minutes); the overall mean difference was 1.7 minutes. The earliest patient admitted to the PACU had received sevoflurane (7.0 +/- 6.3 minutes) and propofol-remifentanil (7.0 +/- 7.4 minutes) whereas patients of the halothane group (9.5 +/- 7.5 minutes) took more. The shortest stay in PACU was seen in patients of the sevoflurane and isoflurane groups (105.13 +/- 35.7 and 108.4 +/- 60.5 minutes), whereas propofol-remifentanil (126.2 +/- 89.1 minutes) and halothan (120.0 +/- 86.1 minutes) anaesthetised patients had the longest stay in PACU. No difference was noted in the incidence of postoperative nausea and vomiting nor in the amount of postoperatively given analgesics. CONCLUSION: Results achieved in routine correspond only in part to results from studies. In our investigation balanced anaesthesia with isoflurane and sevoflurane correspond with the shortest stay in PACU compared to balanced anaesthesia with halothane and IVAs with propofol-fentanyl or propofol-remifentanil. One reason for this could be the intraoperatively administered opioide piritramide in IVAs. Furthermore we conclude that an AIMS may provide additional information about overall costs-effectiveness. However this information depends largely on local factors, e.g. patient case mix, staffing, policy of discharge from the PACU etc.

Adolescent↗
PubMed1984

[Characteristics of middle-latency auditory evoked potentials in awake and anesthetized patients].

Late auditory evoked potentials (50-500 msec latency) can be evoked by tonal stimuli but their instability prevents their use in many clinical situations. In contrast, the early responses (up to 10 msec) are stable, regardless of sleep or sedation, but they can only be evoked by transient, non-tonal stimuli. Therefore neither type may be used for an evaluation of frequency thresholds. The middle latency responses represent a compromise: first, they can be evoked by tonal stimuli of the tone-pip type and, second, they are relatively stable. For these reasons the authors have carried out a general study on the middle latency responses in subjects with normal hearing, in patients with impaired hearing and in patients under a variety of surgical anesthesia. The middle latency response evoked by clicks and tone-pips (4 sines of 500, 1000, 2000 and 4000 Hz) have a series of characteristic waves named, according to their latency, A(V), B(No), C(Po), D(Na), E(Pa). The threshold of visual detection for these potentials is situated near that of the psycho-acoustic threshold (0-20 dB). The authors point out the clinical utilization of the middle latency response especially in cases in which one desires an objective evaluation of the auditory threshold in the lower frequency range. It is important to know that the middle latency response remains present using some types of anesthesia (Ketalar, ataralgesy), disappears partially with neuroleptanesthesia and completely with inhalation anesthesia (fluothane, halothane).

Adult↗
PubMed1977

Antagonism of general anesthesia by naloxone in the rat.

The effect of naloxone, a narcotic antagonist, on the response of animals to painful stimuli during anesthesia was studied. Rats were anesthetized with cyclopropane, halothane, or enflurane in groups of 12. Following induction, inspired anesthetic concentration was gradually reduced to a point at which 35-60 per cent of animals responded to tail clamping. Thereafter the anesthetic concentration was held constant for 30 minutes. Rats in each group then received saline solution or naloxone, 10mg/kg, given intravenously. The response to tail clamping was retested 5 minutes later. In additional experiments EEG's were recorded from rats anesthesized with one of these anesthetics. After a stable light plane of anesthesia had been attained, each animal was given naloxone, 10 mg/kg, iv, and the EEG recorded for an additional 5 minutes. In the tail-clamping experiments, naloxone approximately doubled the number of rats responding during cyclopropane, halothane, or enflurane anesthesia. The EEG patterns of several animals anesthetized with either cyclopropane or halothane changed to patterns consistent with lighter planes of anesthesia after naloxone administration. That naloxone alters the depth of inhalational anesthesia suggests that anesthetics may release an endogenous morphine-like factor (MLF) in the central nervous system.

Anesthesia, General↗
PubMedDate not supplied

Effect of electroacupuncture to prevent selenite-induced cataract in Wistar rats.

PURPOSE: To investigate whether electroacupuncture can prevent selenite-induced cataract in an experimental model. METHODS: Fifty Wistar rat pups were randomized into 5 groups of 10 animals: Group 1 (control), no procedure was performed; Group 2 (selenite), sodium selenite (30 micromoles/kg body weight) was injected subcutaneously between postpartum days 10 to 12; Group 3 (anesthesia) received the same dose of selenite and underwent ether inhalation anesthesia during 10 minutes daily for one week; Group 4 (electroacupuncture) underwent the same procedure of Group 3, but also receiving electroacupuncture (2 Hz, 50 mA) applied to the Neiguan (PC6) and Guangming (GB37) acupoints during the anesthesia period; and Group 5 (Sham) underwent the same procedures of Group 4, but needles were applied to non-acupoints. The development of cataract was assessed one week later, and its density was graded by slit lamp biomicroscopy. RESULTS: All control rats' lenses (Group 1) were clear. Groups 2, 3 and 5 rats developed more severe cataract or complete opacification. In Group 4 (electroacupuncture), 45% of eyes did not develop cataract while thirty per cent developed less severe cataract than Groups 2, 3 and 5. The between-group difference was statistically significant (p<0.001). Lens opacification grade in Groups 1 and 4 was lower than in the Groups 2, 3 and 5 (p<0.001). CONCLUSION: Electroacupuncture effectively decreased selenite-induced cataract formation rate in pup rats when needles were applied at specific acupoints.

Animals↗