bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in Electroencephalogram and Autonomic Cardiovascular Activity during Induction of Anesthesia with Sevoflurane Compared with Halothane in Children
Authors: Constant Isabelle , Dubois Marie-Claude , Piat Véronique , Moutard Marie-Laure , McCue Maggie , Murat Isabelle 
Published: November 2003

Background
This study was design to assess clinical agitation, electroencephalogram (EEG) and autonomic cardiovascular activity changes in children during induction of anesthesia with sevoflurane compared with halothane using noninvasive recording of EEG, heart rate, and finger blood pressure.

Methods
Children aged 2-12 yr premedicated with midazolam were randomly assigned to one of three induction techniques: 7% sevoflurane in 100% O2 (group SevoRAPID); 2%, 4%, 6%, and 7% sevoflurane in 100% O2 (group SevoINCR); or 1%, 2%, 3%, and 3.5% halothane in 50% N2O-50% O2 (group HaloN2O). An additional group of children who received 7% sevoflurane in 50% N2O-50% O2 (group SevoN2O) was enrolled after completion of the study. Induction was videotaped. EEG, heart rate, and finger blood pressure were continuously recorded during induction until 5 min after tracheal intubation and analyzed in frequency domain using spectral analysis.

Results
Agitation was more frequent when anesthesia was induced with 100% O2 compared to the mixture of oxygen and nitrous oxide. No seizures were recorded in any group. In the four groups, induction of anesthesia was associated with an increase in EEG total spectral power and a shift toward the low-frequency bands. Sharp slow waves were present on EEG tracings of the three sevoflurane groups, whereas slow waves and fast rhythms (spindles) were observed in the halothane group. Sevoflurane induced a greater withdrawal of parasympathetic activity than halothane and a transient relative increase in sympathetic vascular tone at loss of eyelash reflex.

Conclusions
Agitation observed during sevoflurane induction was not associated with seizures. Sevoflurane induction induced a marked inhibition of parasympathetic control of heart rate.
Effect of the Duration of Electrical Stimulation on the Analgesic Response in Patients with Low Back Pain
Authors: Hamza Mohamed A. , Ghoname El-sayed A. , White Paul F. , Craig William F. , Ahmed Hesham E. , Gajraj Noor M. , Vakharia Akshay S. , Noe Carl E. 
Published: November 2003

Background
Electrical stimulation of peripheral nerves produces acute analgesic effects. This randomized, sham-controlled, crossover study was designed to evaluate the effect of differing durations of electrical stimulation on the analgesic response to percutaneous electrical nerve stimulation in 75 consenting patients with low back pain.

Methods
All patients received electrical stimulation for four different time intervals (0, 15, 30, and 45 min) in a random sequence over the course of an 11-week study period. All active percutaneous electrical nerve stimulation treatments were administered using alternating frequencies of 15 and 30 Hz three times per week for 2 consecutive weeks. The prestudy assessments included the health status survey short form questionnaire and 10-cm visual analog scale scores for pain, physical activity, and quality of sleep, with 0 being the best and 10 being the worst. The pain scoring was repeated 5-10 min after each 60-min study session and 24 h after the last treatment session with each of the four methods. The daily oral analgesic requirements were assessed during each of the four treatment blocks. At the end of each 2-week treatment block, the questionnaire was repeated.

Results
Electrical stimulation using percutaneously placed needles produced short-term improvements in the visual analog scale pain, physical activity, and quality of sleep scores, and a reduction in the oral analgesic requirements. The 30-min and 45-min durations of electrical stimulation produced similar hypoalgesic effects (48+/-21% and 46+/-19%, respectively) and were significantly more effective than either 15 min (21+/-17%) or 0 min (10+/-11%). The 30- and 45-min treatments were also more effective in improving physical activity and sleep scores over the course of the 2-week treatment period. In contrast to the sham treatment (0 min), the health status survey short form revealed that electrical stimulation for 15 to 45 min three times per week for 2 weeks improved patient function.

Conclusion
The recommended duration of electrical stimulation with percutaneous electrical nerve stimulation therapy is 30 min.
Experimental Pain Augments Experimental Dyspnea, but Not Vice Versa in Human Volunteers
Authors: Nishino Takashi , Shimoyama Naohito , Ide Tohru , Isono Shiroh 
Published: November 2003

Background
Pain and dyspnea frequently coexist in many clinical situations. However, whether the two different symptoms interact with each other has not been elucidated. To elucidate the interaction between pain and dyspneic sensations, the authors investigated separately the effects of pain on dyspnea and the effects of dyspnea on pain in 15 healthy subjects.

Methods
Subjects were asked to rate their sensation of pain or dyspnea using a visual analog scale (VAS) during pain stimulation produced by tourniquet inflation (inflation cuff pressure: 350 mmHg) around the calf, and/or the respiratory loading consisted of a combination of resistive load (77 cm H2O x l(-1) x s(-1)) and hypercapnia induced by extra mechanical dead space (255 ml). In addition to changes in VAS scores, changes in ventilatory airflow and airway pressure were continuously measured.

Results
Pain stimulation and loaded breathing increased VAS scores, ventilation, and occlusion pressure (P0.1). The addition of a pain stimulus during loaded breathing increased the dyspneic VAS score (median 56 [interquartile range 50-62] vs. 64 [55-77]: before vs. after addition of pain stimulus, P < 0.05) with concomitant increases in minute ventilation (10.8 [10.1-13.3] vs. 12.4 [11.0-14.8] l/min, P < 0.05) and P0.1 (5.5 [4.9-7.2] vs. 6.8 [5.8-9.0] cm H2O, P < 0.05). The addition of respiratory loading during pain stimulation did not cause a significant change in pain VAS score (40 [33-55] vs. 31 [30-44]: before vs. after addition of respiratory loading), although both additional burdens increased further minute ventilation (10.0 [8.8-10.9] vs. 12.0 [10.6-13.2] l/min, P < 0.05) and P0.1 (2.5 [2.0-3.0] vs. 6.2 [4.9-7.0] cm H2O, P < 0.05).

Conclusion
The authors' findings suggest that pain intensifies the dyspneic sensation, presumably by increasing the respiratory drive, whereas dyspnea may not intensify the pain sensation.
Beneficial Effects from β-Adrenergic Blockade in Elderly Patients Undergoing Noncardiac Surgery
Authors: Zaugg Michael , Tagliente Thomas , Lucchinetti Eliana , Jacobs Ellis , Krol Marina , Bodian Carol , Reich David L. , Silverstein Jeffrey H. 
Published: November 2003

Background
Perioperative beta-blockade has been shown to improve long-term cardiac outcome in noncardiac surgical patients. A possible mechanism for the reduced risk of perioperative myocardial infarction is the attenuation of the excitotoxic effects of catecholamine surges by beta-blockade. It was hypothesized that beta-blocker-induced alteration of the stress response was responsible for the reported improvements in cardiovascular outcome. Several variables associated with the perioperative use of beta-blockade were also evaluated.

Methods
Sixty-three patients were randomly assigned to one of three groups: group I, no atenolol; group II, pre- and postoperative atenolol; group III, intraoperative atenolol. Hormonal markers of the stress response (neuropeptide Y, epinephrine, norepinephrine, cortisol, and adrenocorticotropic hormone) were evaluated preoperatively and for 72 h after surgery.

Results
Perioperative beta-blockade did not significantly alter the hormonal stress response. However, the beta-blocked patients showed improved hemodynamic stability during emergence and postoperatively. They also received less fentanyl intraoperatively (27.7%, P < 0.0001), experienced faster early recovery, had lower pain scores, and required less analgesia in the postanesthesia care unit. Cardiac troponin I release was detected in 8 of 19, 4 of 20, and 5 of 20 patients in groups I, II, and III, respectively (not significant). Three patients in group I had cardiac troponin I levels consistent with myocardial infarction.

Conclusion
Beta-blockade does not reduce the neuroendocrine stress response, suggesting that this mechanism is not responsible for the previously reported improved cardiovascular outcome. However, it confers several advantages, including decreased analgesic requirements, faster recovery from anesthesia, and improved hemodynamic stability. The release of cardiac troponin I suggests the occurrence of perioperative myocardial damage in this elderly population, which appears to be independent of the neuroendocrine stress response.
Airway Injury during Anesthesia
Authors: Domino Karen B. , Posner Karen L. , Caplan Robert A. , Cheney Frederick W. 
Published: November 2003

Background
Airway injury during general anesthesia is a significant source of morbidity for patients and a source of liability for anesthesiologists. To identify recurrent patterns of injury, the authors analyzed claims for airway injury in the American Society of Anesthesiologists (ASA) Closed Claims Project database.

Methods
The ASA Closed Claims database is a standardized collection of case summaries derived from professional liability insurance companies closed claims files. All claims for airway injury were reviewed in depth and were compared to other claims during general anesthesia.

Results
Approximately 6% (266) of 4,460 claims in the database were for airway injury. The most frequent sites of injury were the larynx (33%), pharynx (19%), and esophagus (18%). Injuries to the esophagus and trachea were more frequently associated with difficult intubation. Injuries to temporomandibular joint and the larynx were more frequently associated with nondifficult intubation. Injuries to the esophagus were more severe and resulted in a higher payment to the plaintiff than claims for other sites of airway injury. Difficult intubation (odds ratio = 4.53, 95% confidence interval [CI] = 2.36, 8.71), age older than 60 yr (odds ratio = 2.97, 95% CI = 1.51, 5.87), and female gender (odds ratio = 2.43, 95% CI = 1.09, 5.42) were associated with claims for pharyngoesophageal perforation. Early signs of perforation, e.g., pneumothorax and subcutaneous emphysema, were present in only 51% of perforation claims, whereas late sequelae, e.g., retropharyngeal abscess and mediastinitis, occurred in 65%.

Conclusion
Patients in whom tracheal intubation has been difficult should be observed for and told to watch for the development of symptoms and signs of retropharyngeal abscess, mediastinitis, or both.
Halothane and Isoflurane Increase Spontaneous but Reduce the N-methyl-D-aspartate–evoked Dopamine Release in Rat Striatal Slices
Authors: Keita Hawa , Henzel-Rouellé Danielle , Dupont Hervé , Desmonts Jean-Marie , Mantz Jean 
Published: November 2003

Background
Experimental data suggest that volatile anesthetics induce significant changes in extracellular dopamine concentrations in the striatum, a restricted but functionally important brain area. In the present study, the authors used a superfused slice preparation to examine the effects of halothane and isoflurane on both spontaneous and N-methyl-D-aspartate (NMDA)-evoked dopamine release in the striatum, and whether these effects involved actions of these anesthetics mediated by gamma-aminobutyric acid receptors in this structure.

Methods
Radioactivity collected from 5-min fractions was compared in the absence (basal release) or presence (evoked release) of NMDA alone and combined with various pharmacologic or anesthetic agents in slices of the dorsolateral striatum and synaptosomes of the whole striatum preloaded with 3H-dopamine and superfused with artificial cerebrospinal fluid.

Results
In tetrodotoxin-treated striatal slices, halothane and isoflurane significantly increased dopamine basal release (EC50 = 0.33 mM and 0.41 mM for halothane and isoflurane, respectively). Both agents decreased the NMDA-evoked dopamine release in both the absence (IC50 = 0.15 mM and 0.14 mM for halothane and isoflurane, respectively) and presence (IC50 = 0.15 mM for both halothane and isoflurane) of tetrodotoxin in slices, and in synaptosomes (IC50 = 0.19 mM for both halothane and isoflurane). NMDA-induced dopamine release was significantly enhanced by bicuculline, a gamma-aminobutyric acid receptor antagonist. Halothane and isoflurane inhibitory effects on NMDA-evoked dopamine release were significantly reduced in the presence of bicuculline.

Conclusion
These results indicate that halothane and isoflurane decrease the NMDA-evoked dopamine release by acting directly at dopamine terminals in striatal slices. They support the involvement of both depression of presynaptic NMDA receptor-mediated responses and enhancement of gamma-aminobutyric acid receptor-mediated responses in these effects.
Influence of Age on Hypnotic Requirement, Bispectral Index, and 95% Spectral Edge Frequency Associated with Sedation Induced by Sevoflurane
Authors: Katoh Takasumi , Bito Hiromichi , Sato Shigehito 
Published: November 2003

Background
Aging is associated with a reduction in anesthetic requirements. The effects of age on the electroencephalographic response to inhalational anesthesia have not been well documented. The objective of the present study was to determine the influence of age on hypnotic requirement and electroencephalographic derivatives such as bispectral index and 95% spectral edge frequency associated with sedation induced by sevoflurane.

Methods
Ninety-six patients were randomly allocated into one of three age groups A, B, and C, ranging in age from 18-39 yr, 40-64 yr, and 65-85 yr, respectively. Patients in each group were sedated with sevoflurane at two predetermined concentrations ranging between 0.45% and 0.85%. The relationship between sevoflurane concentration and response to a verbal command, as well as the relationships between response and bispectral index and 95% spectral edge frequency, was determined.

Results
Multiple regression analysis showed that end-tidal sevoflurane concentration and age significantly affected both bispectral index and 95% spectral edge frequency. ED50 values of sevoflurane concentration for loss of consciousness, defined as no response to verbal command, were different between groups A and C: 0.72 (95% confidence interval: 0.68-0.75) versus 0.59 (95% confidence interval: 0.56-0.62). However, the same effective values of bispectral index and 95% spectral edge frequency at this same clinical end point did not differ.

Conclusions
Increasing age reduced sevoflurane requirements to suppress responses to a verbal command but did not change bispectral index and 95% spectral edge frequency associated with this end point, and in a population with a wide age range, bispectral index would predict depth of sedation better than end-tidal sevoflurane concentration.
Effect of Epidural Blockade on Protein, Glucose, and Lipid Metabolism in the Fasted State and during Dextrose Infusion in Volunteers
Authors: Schricker Thomas , Klubien Kristine , Wykes Linda , Carli Franco 
Published: November 2003

Background
To interpret correctly the results from studies performed during surgery and anesthesia it is necessary to dissect the separate effect of the anesthetic technique itself. The purpose of this study was to investigate the metabolic effects of epidural blockade (T7-S1) with bupivacaine 0.25% after 12 h fasting and during administration of 4 mg x kg(-1) x min(-1) dextrose in six healthy volunteers.

Methods
Each volunteer was assigned to randomly undergo a 6-h multiple stable isotope infusion study (3 h fasted, 3 h dextrose infusion) with or without epidural blockade. L-[1-13C]leucine, [6,6-2H2]glucose, and [1,1,2,3,3-2H5]glycerol were infused to measure protein synthesis, breakdown, and amino acid oxidation; glucose production and clearance; and lipolysis. Plasma concentrations of glucose, lactate, glycerol, free fatty acids, insulin, and glucagon were determined.

Results
Epidural blockade with bupivacaine had no influence on protein oxidation, breakdown and synthesis, glucose production, glucose clearance and lipolysis in the fasted state. Plasma concentrations of metabolic substrates and hormones also were not affected. Dextrose infusion significantly increased glucose clearance and plasma concentrations of glucose and insulin, while endogenous glucose production and lipolysis decreased to a similar degree in both groups. Protein synthesis, breakdown, and oxidation did not change during dextrose infusion.

Conclusions
Epidural blockade with bupivacaine in the absence of surgery has no effect on fasting protein, glucose, and lipid metabolism. Epidural blockade does not modify the inhibitory influence of dextrose administration on endogenous glucose production and lipolysis.
Temperature-dependent Pharmacokinetics and Pharmacodynamics of Vecuronium
Authors: Caldwell James E. , Heier Tom , Wright Peter M. C. , Lin Sean , McCarthy Gerald , Szenohradszky Janos , Sharma Manohar L. , Hing Jeremy P. , Schroeder Marc , Sessler Daniel I. 
Published: November 2003

Background
The authors evaluated the influence of temperature on the pharmacokinetics and pharmacodynamics of vecuronium because mild core hypothermia doubles its duration of action.

Methods
Anesthesia was induced with alfentanil and propofol and maintained with nitrous oxide and isoflurane in 12 healthy volunteers. Train-of-four stimuli were applied to the ulnar nerve, and the mechanical response of the adductor pollicis was measured. Volunteers were actively cooled or warmed until their distal esophageal temperatures were in one of four ranges: < 35.0 degrees C, 35.0-35.9 degrees C, 36.0-36.9 degrees C, and > or = 37.0 degrees C. With temperature stabilized, vecuronium was infused at 5 microg x kg(-1) x min(-1) until the first response of each train-of-four had decreased by 70%. Arterial blood (for vecuronium analysis) was sampled at intervals until the first response recovered to at least 90% of its prevecuronium level. Vecuronium, 20 microg x kg(-1) x min(-1), was then infused for 10 min, and arterial blood was sampled at intervals for up to 7 h. Population-based nonlinear mixed-effects modeling was used to examine the effect of physical characteristics and core temperature on vecuronium pharmacokinetics and pharmacodynamics.

Results
Decreasing core temperature over 38.0-34.0 degrees C decreases the plasma clearance of vecuronium (11.3% per degrees C), decreases the rate constant for drug equilibration between plasma and effect site (0.023 min(-1) per degrees C), and increases the slope of the concentration-response relationship (0.43 per degrees C).

Conclusions
Our results show that reduced clearance and rate of effect site equilibration explain the increased duration of action of vecuronium with reducing core temperature. Tissue sensitivity to vecuronium is not influenced by core temperature.
Patient-controlled Interscalene Analgesia with Ropivacaine 0.2%Versus Patient-controlled Intravenous Analgesia after Major Shoulder Surgery
Authors: Borgeat Alain , Perschak Henry , Bird Patricia , Hodler Juerg , Gerber Christian 
Published: November 2003

Background
The authors compared the effects of patient-controlled interscalene analgesia (PCIA) with ropivacaine 0.2% and patient-controlled intravenous analgesia (PCIVA) with opioids on hemidiaphragmatic excursion and respiratory function after major shoulder surgery.

Methods
Thirty-five patients scheduled for elective major shoulder surgery were prospectively randomized to receive either PCIA or PCIVA. All patients received an interscalene block before surgery. In the PCIA group, a catheter was introduced between the anterior and middle scalene muscles. Six hours after the initial block, patients received for 48 h either a continuous infusion of 0.2% ropivacaine through the interscalene catheter at a rate of 5 ml/h plus a bolus dose of 3 or 4 ml with a lockout time of 20 min (PCIA group) or a continuous intravenous infusion of nicomorphine at a rate or 0.5 mg/h plus a bolus dose of 2 or 3 mg with a lockout time of 20 min (PCIVA group). Hemidiaphragmatic excursion and respiratory function were assessed with the patient in a 45 degrees semirecumbent position the day before the operation and 20 min (in the operating room), 24 h, and 48 h after the initial block by means of ultrasonography and spirometry, respectively. Pain relief was regularly assessed, side effects were noted, and patient satisfaction was rated 6 h after the end of the study.

Results
Hemidiaphragmatic excursion was similar in the two groups 20 min after interscalene block. Hemidiaphragmatic excursion was increased in the PCIA group on the nonoperated side 24 and 48 h after the interscalene block (P < 0.05). Pulmonary function was similar in the two groups at each time. Pain was better controlled in the PCIA group at 12 and 24 h (P < 0.05). The incidence of nausea and vomiting were 5.5% versus 60% for the PCIA and PCIVA groups, respectively (P < 0.05). Patient satisfaction was greater in the PCIA group (P < 0.05).

Conclusions
The use of PCIA or PCIVA techniques to provide analgesia after major shoulder surgery is associated with similar effects on respiratory function. In the PCIA group, hemidiaphragmatic excursion showed a significantly greater amplitude 24 and 48 h after the initial block on the nonoperated side. The PCIA technique provided better pain control, a lower incidence of side effects, and a higher degree of patient satisfaction.
Effects of Intravenous Anesthetics on Ca2+ Sensitivity in Canine Tracheal Smooth Muscle
Authors: Hanazaki Motohiko , Jones Keith A. , Warner David O. 
Published: November 2003

Background
Halothane and other volatile anesthetics relax airway smooth muscle in part by decreasing the amount of force produced for a particular intracellular calcium concentration (the Ca2+ sensitivity) during muscarinic receptor stimulation. In this study, ketamine, propofol, and midazolam were evaluated to determine whether the inhibitory effect of volatile anesthetics on this signal transduction pathway is a general property of other types of anesthetic drugs.

Methods
A beta-escin permeabilized canine tracheal smooth muscle preparation was used. Ketamine, propofol, and midazolam, in concentrations producing near-maximal relaxation in intact airway smooth muscle (200 microM, 270 microM, and 100 microM, respectively), were applied to permeabilized muscles stimulated with calcium in either the absence or the presence of muscarinic receptor stimulation provided by acetylcholine. The effect of halothane also was evaluated.

Results
Confirming previous studies, halothane (0.75 mM) decreased calcium sensitivity during muscarinic receptor stimulation. None of the intravenous anesthetics studied affected Ca2+ sensitivity, either in the absence or the presence of muscarinic receptor stimulation.

Conclusions
Intravenous anesthetics in high concentrations directly relax canine tracheal smooth muscle without affecting Ca2+ sensitivity. The inhibition of agonist-induced increases in Ca2+ sensitivity of canine tracheal smooth is not a common property of anesthetics, but is unique to volatile agents.