bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Prophylactic Bronchodilator Treatment with Intravenous Colforsin Daropate, a Water-soluble Forskolin Derivative, on Airway Resistance after Tracheal Intubation
Authors: Wajima Zen'ichiro , Shiga Toshiya , Yoshikawa Tatsusuke , Ogura Akira , Imanaga Kazuyuki , Inoue Tetsuo , Ogawa Ryo 
Published: November 2003

Background
After induction of anesthesia, lung resistance increases. The authors hypothesized that prophylactic bronchodilator treatment with intravenous colforsin daropate, a water-soluble forskolin derivative, before tracheal intubation would result in decreased lung resistance and increased lung compliance after tracheal intubation when compared with placebo medication.

Methods
Forty-six adult patients were randomized to placebo or colforsin daropate treatment. Patients in the control group received normal saline; patients in the colforsin group received 0.75 microg. kg-1 x min-1 colforsin daropate intravenously until the study ended. Thirty minutes after the study began, the authors administered 5 mg/kg thiamylal and 5 microg/kg fentanyl for induction of general anesthesia and 0.3 mg/kg vecuronium for muscle relaxation. A 15-mg. kg-1. h-1 continuous infusion of thiamylal followed anesthetic induction. Four, 8, 12, and 16 min after tracheal intubation, mean airway resistance (R(awm)), expiratory airway resistance (R(awe)), and dynamic lung compliance (C(dyn)) were measured.

Results
Patients in the colforsin group had significantly lower R(awm) and R(awe) and higher C(dyn) after intubation than those in the control group. Differences in R(awm), R(awe), and C(dyn) between the two groups persisted through the final measurement at 16 min. At 4 min after intubation, smokers had a higher R(awm) and a lower C(dyn) than nonsmokers in the control group. After treatment by intravenous colforsin daropate, R(awm), R(awe), and C(dyn) values were similar for smokers and nonsmokers after tracheal intubation.

Conclusions
Prophylactic treatment with colforsin daropate produced lower R(awm) and R(awe) and higher C(dyn) after tracheal intubation when compared with placebo medication. Pretreatment before intubation may be beneficial and advantageous for middle-aged smokers.
Relationship between Aortic-to-radial Arterial Pressure Gradient after Cardiopulmonary Bypass and Changes in Arterial Elasticity
Authors: Kanazawa Masahiro , Fukuyama Haruo , Kinefuchi Yoshio , Takiguchi Mamoru , Suzuki Toshiyasu 
Published: November 2003

Background
An aortic-to-radial arterial pressure gradient may develop during and after cardiopulmonary bypass (CPB). The mechanisms of this pressure gradient remain controversial. To clarify the cause of the pressure gradient after CPB, the authors investigated the relationship between the pressure gradient and changes in the pulse wave velocity (PWV) before and after CPB.

Methods
The pressure gradient from the aorta to the radial artery and a change in PWV were measured with a wire (0.37 mm in diameter) tipped with a miniature pressure transducer in 12 patients undergoing cardiac surgery. The pressure distributions and waveforms were measured and recorded with electrocardiograph. The PWV was calculated by measuring the propagation time between the R wave of the electrocardiograph and the rising point of the arterial pressure waveform at 10-cm intervals.

Results
After CPB, 7 of 12 patients demonstrated a marked pressure gradient. In these patients, the pressure distribution showed a gradual decrease toward the periphery without a precipitous step-down in pressure at any one specific anatomic location. The PWV decreased as the intraarterial pressure decreased from the aorta to the radial artery, and the relative arterial elasticity decreased linearly toward the periphery.

Conclusions
The results showed that the decrease in PWV implies a decrease in arterial elasticity, and the decrease in the arterial elasticity correlated with the decrease in intraarterial pressure. These findings demonstrated that a radial artery pressure lower than the aortic pressure after CPB may be due to the decrease in arterial elasticity.
Cricoid Pressure Displaces the Esophagus: An Observational Study Using Magnetic Resonance Imaging
Authors: Smith Kevin J. , Dobranowski Julian , Yip Gordon , Dauphin Alezandre , Choi Peter T-L. 
Published: November 2003

Background
Cricoid pressure (CP) is often used during general anesthesia induction to prevent passive regurgitation of gastric contents. The authors used magnetic resonance imaging to determine the anatomic relationship between the esophagus and the cricoid cartilage ("cricoid") with and without CP.

Methods
Magnetic resonance images of the necks of 22 healthy volunteers were reviewed with and without CP. Esophageal and airway dimensions, distance between the midline of the vertebral body and the midline of the esophagus, and distance between the lateral border of the cricoid or vertebral body and the lateral border of the esophagus were measured.

Results
The esophagus was displaced laterally relative to the cricoid in 52.6% of necks without CP and 90.5% with CP. CP shifted the esophagus relative to its initial position to the left in 68.4% of subjects and to the right in 21.1% of subjects. Unopposed esophagus was seen in 47.4% of necks without CP and 71.4% with CP. Lateral laryngeal displacement and airway compression were demonstrated in 66.7% and 81.0% of necks, respectively, as a result of CP.

Conclusion
In the absence of CP, the esophagus was lateral to the cricoid in more than 50% of the sample. CP further displaced both the esophagus and the larynx laterally.
Systemically Administered α2-Agonist-induced Peripheral Vasoconstriction in Humans
Authors: Talke Pekka , Lobo Errol , Brown Ronald 
Published: November 2003

Background
alpha(2)-Adrenoceptors mediate both sympatholytic and vasoconstrictive hemodynamic effects. The goal of this study was to profile the peripheral vasoconstrictive effects of a selective alpha(2)-adrenoceptor agonist in isolation from the sympatholytic effects it also induces.

Methods
The authors administered increasing plasma target concentrations of dexmedetomidine (0.075, 0.15, 0.3, and 0.6 ng/mL) or saline placebo to healthy young volunteers in whom the sympatholytic effects of the drug were attenuated in one of two ways: general anesthesia (propofol-alfentanil-nitrous oxide) or axillary brachial plexus block. Measurements were made of finger blood volume (an indicator of vasoconstriction) by photoplethysmographic determination of light transmitted through a finger (LTF) and hemodynamic variables. Measurements made before and during the four steps of infusion were compared by repeated-measures ANOVA.

Results
In anesthetized volunteers, all concentrations of dexmedetomidine increased LTF (vasoconstriction) and systolic blood pressure (P < 0.001 for both), whereas placebo did not. In awake volunteers, all concentrations decreased systolic blood pressure (P < 0.001). Concentrations of 0.15, 0.3, and 0.6 ng/mL decreased LTF (vasodilation) in the neurally intact hand; in contrast, the same concentrations increased LTF (vasoconstriction) in the sympathectomized hand (P < 0.001 for both).

Conclusions
The results of this study are the first to characterize the lower end of the dose-response curve for vasoconstriction induced by dexmedetomidine. By denervating the vascular bed of interest or by decreasing sympathetic nervous system activity, the authors were able to observe vasoconstriction induced by a systemically administered alpha(2)-agonist with minimal interference from the sympatholytic effects of the drug.
Effects of Inhalational Anesthetics on L-type Ca2+Currents in Human Atrial Cardiomyocytes during β-Adrenergic Stimulation
Authors: Fassl Jens , Halaszovich Christian R. , Hüneke Rocco , Jüngling Eberhard , Rossaint Rolf , Lückhoff Andreas 
Published: November 2003

Background
Anesthetics may cause cardiac side effects by their action on L-type Ca2+ channels. Direct effects on the channels have not yet been discriminated from an interference with the beta-adrenergic channel regulation. The authors therefore studied the effects of halothane, sevoflurane, and xenon on human cardiac Ca2+ currents during stimulation with isoproterenol.

Methods
Currents through L-type Ca2+ channels were measured with the patch clamp technique in atrial cardiomyocytes obtained from patients undergoing cardiac surgery. Cells were superfused with solutions equilibrated with anesthetics at the desired concentrations. Ca2+ currents during pulses to 10 mV were evaluated with respect to their peak value (I(max)) and to the total moved charge (Q).

Results
In the absence and in the presence of isoproterenol (1 microm), sevoflurane (0.29 mm, 1 minimum alveolar concentration [MAC]) significantly depressed Q by 37.8 +/- 7.2% (mean +/- SD) and 40.8 +/- 10.3%, respectively. I(max) was not significantly affected in comparison with control cells never exposed to an anesthetic. Xenon (65%, 1 MAC) did not evoke significant effects. Exposure to halothane (0.39 mm, 1 MAC) during stimulation with isoproterenol significantly reduced Q by 31.3 +/- 23.3% (but not I(max)). After washout of halothane, Q was increased above the level prior to the application of halothane. Moreover, whereas Q promptly declined to baseline levels after washout of isoproterenol in controls, the previous exposure to halothane markedly delayed this decline, leaving Q significantly elevated for several minutes.

Conclusions
Halothane exerts a dual effect on Ca2+ currents. The long-lasting stimulatory effect may contribute to the proarrhythmic potency of the drug that exceeds that of sevoflurane, which only depressed Ca2+ currents.
Improved Resuscitation after Cardiac Arrest in Rats Expressing the Baculovirus Caspase Inhibitor Protein p35 in Central Neurons
Authors: Vogel Peter , Putten Herman v.d. , Popp Erik , Krumnikl Jakub J. , Teschendorf Peter , Galmbacher Roland , Kisielow Malgorzata , Wiessner Christoph , Schmitz Albert , Tomaselli Kevin J. , Schmitz Bernd , Martin Eike , Böttiger Bernd W. 
Published: November 2003

Background
Global cerebral ischemia is associated with delayed neuronal death. Given the role of caspases in apoptosis, caspase inhibitors may provide neuronal protection after cardiac arrest. To this end, the authors generated a transgenic rat line expressing baculovirus p35, a broad-spectrum caspase inhibitor, in central neurons. Its effects were evaluated on neuronal cell death and outcome after global cerebral ischemia.

Methods
Global cerebral ischemia was induced by cardiocirculatory arrest. After 6 min, animals were resuscitated by controlled ventilation, extrathoracic cardiac massage, epinephrine, and electrical countershocks. Neuronal death was assessed after 7 days by histologic evaluation of the hippocampal cornu ammonis 1 sector. Postischemic outcome was assessed by determination of overall survival and according to neurologic deficit scores 24 h, 3 days, and 7 days after resuscitation.

Results
The rate of 7-day survival after cardiac arrest for the transgenic rats (85%) was significantly higher than that for the nontransgenic controls (52%; P < 0.05). However, no differences were observed either in the number of terminal deoxynucleotidyltransferase-mediated d-uracil triphosphate-biotin nick end-labeling-positive cells or viable neurons in the cornu ammonis 1 sector or in the neurologic deficit score when comparing surviving transgenic and nontransgenic rats. These findings suggest that neuronal apoptosis after cardiac arrest is not primarily initiated by activation of caspases.

Conclusion
Expression of baculovirus p35 can improve survival after cardiac arrest in rats, but the mode and site of action remain to be elucidated.
Differential Uptake of Volatile Agents into Brain Tissue In Vitro
Authors: Chesney Michael A. , Perouansky Misha , Pearce Robert A. 
Published: November 2003

Background
The rate of onset of drug actions in experiments with brain slices in vitro can vary widely. One factor that influences the rate is access to tissue sites of action. To study the effects of the nonimmobilizer 1,2-dichlorohexafluorocyclobutane (F6, also termed 2N in the literature) on physiologic processes under defined tissue concentrations, the authors performed electrophysiologic measurements of the effects of F6 and halothane, measured the uptake of these agents into brain tissue, and performed computational modeling to determine concentration-depth profiles during drug application.

Methods
Hippocampal brain slices 500 microm thick were prepared from adult rats. Evoked population responses in the CA1 region were obtained using extracellular recordings and electrical stimulation of the Schaffer collateral pathway. F6 (24 microm) and halothane (270 microm) were applied via superfusion for 40 min. Uptake of drug into tissue slices was measured using gas chromatography. Computational modeling was used to obtain estimates of drug diffusion coefficients in brain tissue and to calculate tissue concentration as a function of time and depth during drug application.

Results
Halothane reduced the amplitude of the evoked population spike and reduced the population excitatory postsynaptic potential slope. F6 had no effect on either measure. Uptake experiments yielded a diffusion coefficient of 0.1 x 10-6 cm2/s for F6 and 0.8 x 10-6 cm2/s for halothane. After 40 min of drug application, the concentration reached at tissue depths from which physiologic signals were obtained, approximately the top 200 microm of the slice, was estimated to be 58% of the final equilibrium value for F6 and 93% for halothane.

Conclusions
Diffusion into tissue is substantially slower for F6 than for halothane, and its impact is great enough that this must be considered when designing or interpreting in vitro experiments. However, impaired access does not account for the lack of effect of F6 on electrophysiologic responses in rat hippocampal slices.
Postoperative Morphine Consumption in the Elderly Patient
Authors: Aubrun Frédéric , Bunge Dorothea , Langeron Olivier , Saillant Gérard , Coriat Pierre , Riou Bruno 
Published: November 2003

Background
It has been suggested that the dose of intravenous morphine used during postoperative titration is not modified by aging. The authors therefore studied morphine requirements in patients undergoing total hip replacement.

Methods
Intravenous morphine titration was administered as boluses, then subcutaneous morphine was administered every 4 h over 24 h. Pain was assessed by use of the visual analog scale (0 to 100), and the threshold required to administer morphine was 30. Young and elderly (> or =70 yr old) patients were compared. Data are mean +/- SD or odds ratio (OR) [95% CI].

Results
Two hundred twenty-four patients (68%) were young and 105 (32%) were elderly. The initial visual analog scale was not significantly different between groups. The dose of intravenous morphine in the postanesthesia care unit was not significantly different between young and elderly patients (0.15 +/- 0.11 vs. 0.14 +/- 0.10 mg/kg, P = NS), in contrast to the dose of subcutaneous morphine (0.18 +/- 0.18 vs. 0.11 +/- 0.11 mg/kg, P < 0.001) in the ward. Only severe pain (visual analog scale of 70 or greater; OR, 10.5 [4.5-24.8]) was significantly associated with a high dose (greater than 0.15 mg/kg) of intravenous morphine, whereas severe pain (OR, 2.5 [1.6-4.0]), age less than 60 yr (OR, 2.3 [1.4-3.8]), and absence of a nonsteroidal antiinflammatory drug (OR, 1.9 [1.2-3.1]) were significantly associated with a high dose (greater than 0.12 mg/kg) of subcutaneous morphine.

Conclusions
The dose of intravenous morphine during titration is not modified in elderly patients, in contrast to the dose administered subcutaneously over a prolonged period.
Cephalad Movement of Morphine and Fentanyl in Humans after Intrathecal Injection
Authors: Eisenach James C. , Hood David D. , Curry Regina , Shafer Steven L. 
Published: November 2003

Background
Despite decades of use, controversy remains regarding the extent and time course of cephalad spread of opioids in cerebrospinal fluid (CSF) after intrathecal injection. The purpose of this study was to examine differences between two often used opioids, morphine and fentanyl, in distribution in the CSF after intrathecal injection.

Methods
Eight healthy volunteers received intrathecal injection of morphine (50 microg) plus fentanyl (50 microg) at a lower lumbar interspace. CSF was sampled through a needle in an upper lumbar interspace for 60-120 min. At the end of this time, a sample was taken from the lower lumbar needle, and both needles were withdrawn. CSF volume was determined by magnetic resonance imaging. Pharmacokinetic modeling was performed with NONMEM.

Results
Morphine and fentanyl peaked in CSF at the cephalad needle at similar times (41 +/- 13 min for fentanyl, 57 +/- 12 min for morphine). The ratio of morphine to fentanyl in CSF at the cephalad needle increased with time, surpassing 2:1 by 36 min and 4:1 by 103 min. CSF concentrations did not correlate with weight, height, or lumbosacral CSF volume. The concentrations of morphine and fentanyl at both sampling sites were well described by a simple pharmacokinetic model. The individual model parameters did not correlate with the distance between the needles, CSF volume, patient height, or patient weight.

Conclusions
Fentanyl is cleared more rapidly from CSF than morphine, although their initial distribution in the first hour after injection does not differ greatly. The pharmacokinetic model demonstrates that mixing is the primary determinant of early concentrations and is highly variable among individuals.
Predictors of Survival following Cardiac Arrest in Patients Undergoing Noncardiac Surgery
Authors: Sprung Juraj , Warner Mary E. , Contreras Michael G. , Schroeder Darrell R. , Beighley Christopher M. , Wilson Gregory A. , Warner David O. 
Published: November 2003

Background
The authors determined the incidence of cardiac arrest and predictors of survival following perioperative cardiac arrest in a large population of patients at a tertiary referral center.

Methods
Medical records of patients who experienced cardiac arrest in the perioperative period surrounding noncardiac surgery between January 1, 1990, and December 31, 2000, were reviewed. Logistic regression identified characteristics associated with immediate (>or= 1 h) and hospital survival, with P <or= 0.01 considered statistically significant.

Results
Cardiac arrest occurred in 223 of 518,294 anesthetics (4.3 per 10,000) during the study period. Frequency of arrest for patients receiving general anesthesia decreased over time (7.8 per 10,000 during 1990-1992; 3.2 per 10,000 during 1998-2000). The frequency of arrest during regional anesthesia (1.5 per 10,000) and monitored anesthesia care (0.7 per 10,000) remained consistent. Immediate survival after arrest was 46.6%, and hospital survival was 34.5%. Twenty-four patients (0.5 per 10,000) had cardiac arrest related primarily to anesthesia. From multivariate analysis, patients who experienced arrest due to bleeding were less likely to survive hospitalization (P = 0.001). Survival was also lower for patients who experienced arrest during nonstandard working hours (P = 0.006) and for patients who had protracted hypotension before arrest (P < 0.001).

Conclusions
The overall frequency of arrest for patients receiving anesthesia decreased during the study period. Most arrests were not due to anesthesia-related causes, and most patients experiencing anesthesia-related arrest survived to hospital discharge. Although many factors determining survival may not be amenable to modification, the fact that arrests during nonregular working hours had worse outcomes may indicate that the availability of human resources influences survival.
Effects of Propofol, Desflurane, and Sevoflurane on Recovery of Myocardial Function after Coronary Surgery in Elderly High-risk Patients
Authors: De Hert Stefan G. , Cromheecke Stefanie , ten Broecke Pieter W. , Mertens Els , De Blier Ivo G. , Stockman Bernard A. , Rodrigus Inez E. , Van der Linden Philippe J. 
Published: November 2003

Background
The present study investigated the effects of propofol, desflurane, and sevoflurane on recovery of myocardial function in high-risk coronary surgery patients. High-risk patients were defined as those older than 70 yr with three-vessel disease and an ejection fraction less than 50% with impaired length-dependent regulation of myocardial function.

Methods
Coronary surgery patients (n = 45) were randomly assigned to receive either target-controlled infusion of propofol or inhalational anesthesia with desflurane or sevoflurane. Cardiac function was assessed perioperatively and during 24 h postoperatively using a Swan-Ganz catheter. Perioperatively, a high-fidelity pressure catheter was positioned in the left and right atrium and ventricle. Response to increased cardiac load, obtained by leg elevation, was assessed before and after cardiopulmonary bypass (CPB). Effects on contraction were evaluated by analysis of changes in dP/dt(max). Effects on relaxation were assessed by analysis of the load-dependence of myocardial relaxation. Postoperative levels of cardiac troponin I were followed for 36 h.

Results
After CPB, cardiac index and dP/dt(max) were significantly lower in patients under propofol anesthesia. Post-CPB, leg elevation resulted in a significantly greater decrease in dP/dt(max) in the propofol group, whereas the responses in the desflurane and sevoflurane groups were comparable with the responses before CPB. After CPB, load dependence of left ventricular pressure drop was significantly higher in the propofol group than in the desflurane and sevoflurane group. Troponin I levels were significantly higher in the propofol group.

Conclusions
Sevoflurane and desflurane but not propofol preserved left ventricular function after CPB in high-risk coronary surgery patients with less evidence of myocardial damage postoperatively.