bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessment of the Intrarater and Interrater Reliability of an Established Clinical Task Analysis Methodology
Authors: Slagle Jason , Weinger Matthew B. , Dinh My-Than T. , Brumer Vanessa V. , Williams Kevin 
Published: November 2003

Background
Task analysis may be useful for assessing how anesthesiologists alter their behavior in response to different clinical situations. In this study, the authors examined the intraobserver and interobserver reliability of an established task analysis methodology.

Methods
During 20 routine anesthetic procedures, a trained observer sat in the operating room and categorized in real-time the anesthetist's activities into 38 task categories. Two weeks later, the same observer performed task analysis from videotapes obtained intraoperatively. A different observer performed task analysis from the videotapes on two separate occasions. Data were analyzed for percent of time spent on each task category, average task duration, and number of task occurrences. Rater reliability and agreement were assessed using intraclass correlation coefficients.

Results
Intrarater reliability was generally good for categorization of percent time on task and task occurrence (mean intraclass correlation coefficients of 0.84-0.97). There was a comparably high concordance between real-time and video analyses. Interrater reliability was generally good for percent time and task occurrence measurements. However, the interrater reliability of the task duration metric was unsatisfactory, primarily because of the technique used to capture multitasking.

Conclusions
A task analysis technique used in anesthesia research for several decades showed good intrarater reliability. Off-line analysis of videotapes is a viable alternative to real-time data collection. Acceptable interrater reliability requires the use of strict task definitions, sophisticated software, and rigorous observer training. New techniques must be developed to more accurately capture multitasking. Substantial effort is required to conduct task analyses that will have sufficient reliability for purposes of research or clinical evaluation.
Frequency of Myocardial Infarction, Pulmonary Embolism, Deep Venous Thrombosis, and Death following Primary Hip or Knee Arthroplasty
Authors: Wood Margaret , Mantilla Carlos B. , Horlocker Terese T. , Schroeder Darrell R. , Berry Daniel J. , Brown David L. 
Published: November 2003

Background
There is limited information about the frequency of perioperative complications after elective primary orthopedic total hip and knee arthroplasty in contemporary practice. The purpose of this study was to determine the frequency of clinically relevant myocardial infarction, pulmonary embolism, deep venous thrombosis, and death within 30 days after elective primary hip or knee arthroplasty treated according to contemporary perioperative management.

Methods
The authors examined the medical records of consecutive patients undergoing hip or knee arthroplasty at their institution in a 10-yr period. Prospectively collected databases were used to identify patients with the diagnosis of myocardial infarction, pulmonary embolism, deep venous thrombosis, or death using strict validation criteria and diagnostic-certainty categories.

Results
A total of 10,244 patients underwent primary total hip or knee arthroplasty in the period of study. Of these, 224 patients had one or more adverse events (overall event rate: 2.2%; myocardial infarction: 0.4%; pulmonary embolism: 0.7%; deep venous thrombosis: 1.5%; death: 0.5%). Most adverse events (myocardial infarction, pulmonary embolism, and death) increased in frequency with older age, particularly for patients aged 70 yr or older. Myocardial infarction occurred more frequently in male patients. There were no differences in the overall event frequency between types of procedure. However, pulmonary embolism was highest in patients undergoing bilateral knee operations.

Conclusions
The overall frequency of serious complications within 30 days after primary total hip or knee arthroplasty with contemporary practice was 2.2%. Accurate knowledge of the perioperative risks associated with widely performed elective operations can be used to implement management strategies that may further improve patient outcomes and decrease cost.
Spinal GABAAand GABABReceptor Pharmacology in a Rat Model of Neuropathic Pain
Authors: Malan T. Philip , Mata Heriberto P. , Porreca Frank 
Published: November 2003

Background
This study tests the hypothesis that loss of spinal activity of gamma-aminobutyric acid (GABA) contributes to the allodynia and hyperalgesia observed after peripheral nerve injury.

Methods
Intrathecal catheters were implanted in male Sprague-Dawley rats. Antinociception was assessed by measuring withdrawal latency to immersion of the tail in a 52 degrees C water bath. Nerve injury was produced by ligation of the L5 and L6 spinal nerves. Testing was performed 4-14 days after spinal nerve ligation, when tactile allodynia and thermal hyperalgesia were established. Tactile allodynia was quantitated using the threshold to withdrawal of the hind paw on probing with von Frey filaments. Thermal hyperalgesia was quantitated using the latency to withdrawal of the hind paw from radiant heat. Motor function was tested using a rotarod apparatus.

Results
Spinal administration of the GABAA receptor antagonist bicuculline or the GABAB receptor antagonist phaclofen produced tactile allodynia and thermal hyperalgesia in normal rats. The GABAB receptor agonist baclofen, administered spinally, produced antinociception in the tail-flick test, whereas the GABAA receptor agonist isoguvacine did not. Isoguvacine and baclofen each reversed tactile allodynia and thermal hyperalgesia produced by spinal nerve ligation. Baclofen but not isoguvacine prolonged thermal withdrawal latency in nerve-injured rats beyond preoperative values. Baclofen but not isoguvacine impaired motor function.

Conclusions
Pharmacologic inhibition of intrinsic GABA tone in normal rats resulted in tactile allodynia and thermal hyperalgesia, consistent with the hypothesis being tested. Exogenous administration of GABA agonists reversed spinal nerve ligation-induced allodynia and hyperalgesia, also consistent with this hypothesis. Isoguvacine produced specific antihyperalgesic and antiallodynic effects, whereas assessment of the effects of baclofen was complicated by motor dysfunction. Spinal GABAA agonists may provide a specific therapy for neuropathic pain.
Intracerebroventricular Morphine Produces Antinociception by Evoking γ-Aminobutyric Acid Release through Activation of 5-Hydroxytryptamine 3 Receptors in the Spinal Cord
Authors: Kawamata Tomoyuki , Omote Keiichi , Toriyabe Masaki , Kawamata Mikito , Namiki Akiyoshi 
Published: November 2003

Background
It has been generally considered that supraspinal morphine activates the serotonergic descending inhibitory system and releases serotonin (5-hydroxytryptamine [5-HT]) in the spinal cord, producing antinociception through activation of 5-HT receptors. The involvement of a spinal gamma-aminobutyric acid-mediated (GABAergic) system is also suggested in supraspinal morphine antinociception. It has been reported that spinal GABAergic system contributes to 5-HT3 receptor-mediated antinociception. In this study, the authors investigated the contribution of spinal 5-HT3 receptor and the GABAergic system in the intracerebroventricular morphine-induced antinociception.

Methods
Male Sprague-Dawley rats were used. Using the spinal microdialysis method, concentrations of 5-HT and GABA were measured after intracerebroventricular morphine administration. The effect of intracerebroventricular naloxone or spinal perfusion of a selective 5-HT3 receptor antagonist 3-tropanyl-indole-3-carboxylate methiodide on the spinal release of GABA after intracerebroventricular morphine administration was also examined. In the behavioral study, involvement of 5-HT3 receptors or GABAA receptors in the intracerebroventricular morphine-induced antinociceptive effect was investigated using the tail-flick test.

Results
Intracerebroventricular morphine (40 nmol) significantly increased spinal GABA and 5-HT release. Evoked spinal GABA release was reversed by intracerebroventricular naloxone (40 nmol) or spinal perfusion of 3-tropanyl-indole-3-carboxylate methiodide (1 mm). In the behavioral study, intracerebroventricular morphine produced significant antinociception. Intrathecal administration of either GABAA receptor antagonist bicuculine or 3-tropanyl-indole-3-carboxylate methiodide but not vehicle reversed the morphine-induced antinociceptive effect.

Conclusion
Intracerebroventricular morphine evokes spinal GABA release via the activation of 5-HT3 receptors in the spinal cord, resulting in antinociceptive effect.
Propofol Anesthesia Compared to Awake Reduces Infarct Size in Rats
Authors: Gelb Adrian W. , Bayona Nestor A. , Wilson John X. , Cechetto David F. 
Published: November 2003

Background
Propofol has not been studied directly in animals subject to cerebral ischemia in the conscious state. Strokes are usually induced in animals while they are anesthetized, making it difficult to eliminate anesthetic interactions as a complicating factor. Therefore, to compare the neuroprotective effects of propofol to the unanesthetized state, experiments were performed using a model that induces a stroke in the conscious rat.

Methods
Cerebral ischemia was induced in awake Wistar rats by a local intracerebral injection of the potent vasoconstrictor endothelin. Four days before the strokes were induced, a guide cannula was implanted for the injection of endothelin. On the day of the experiment, endothelin (6.0 pmol in 3 microl) was injected into the striatum. Propofol (25 or 15 mg. kg-1. h-1) or intralipid (vehicle) were infused for 4 h starting immediately after the endothelin injection. In another series, the propofol infusion was begun 1 h after the endothelin injection and continued for 4 h. Three days later, the animals were killed, and the brains were sectioned and stained.

Results
The propofol group (25 mg. kg-1. h-1) had a significantly reduced infarct size (0.7 +/- 0.21 mm3, first 4 h; 0.27 +/- 0.07 mm3, started 1 h after initiation of infarct) compared with the intralipid controls (3.40 +/- 0.53 mm3). To exclude a direct interaction between propofol and endothelin, in thiobutabarbital anesthetized rats, endothelin-induced cerebral vasoconstriction was examined using videomicroscopy, with or without propofol. Propofol had no effect on the magnitude or time course of the endothelin-induced vasoconstriction.

Conclusions
The results show that concurrent or delayed administration of propofol is neuroprotective.
Involvement of the Mitogen-activated Protein Kinase Family in Tetracaine-induced PC12 Cell Death
Authors: Tan Zhiming , Dohi Shuji , Chen Jinen , Banno Yosiko , Nozawa Yoshinori 
Published: November 2003

Background
To explore whether cytotoxicity of local anesthetics is related to apoptosis, the authors examined how local anesthetics affect mitogen-activated protein kinase (MAPK) family members, extracellular signal-regulated kinases (ERKs), c-Jun N-terminal kinases (JNKs)-stress-activated protein kinases, and p38 kinase, which are known to play important roles in apoptosis.

Methods
Cell death was evaluated using PC12 cells. Morphologic changes of cells, cellular membrane, and nuclei were observed. DNA fragmentation was electrophoretically assayed. Western blot analysis was performed to analyze phosphorylation of the MAPK family, cleavage of caspase-3 and poly(adenosine diphosphate-ribose) polymerase. Intracellular Ca2+ concentration was measured using a calcium indicator dye.

Results
Tetracaine-induced cell death was shown in a time- and concentration-dependent manner and characterized by nuclear condensation or fragmentation, membrane blebbing, and internucleosomal DNA fragmentation. Caspase-3 activation and phosphorylation of ERK, JNK, and p38 occurred in the cell death. PD98059, an inhibitor of ERK, enhanced tetracaine-induced cell death and JNK phosphorylation, whereas ERK phosphorylation was inhibited. Curcumin, an inhibitor of JNK pathway, attenuated the cell death. Increase of intracellular Ca2+ concentration was detected. In addition to the increase of ERK phosphorylation and the decrease of JNK phosphorylation, two Ca2+ chelators protected cells from death. Neither cell death nor phosphorylation of the MAPK family was caused by tetrodotoxin. Nifedipine did not affect tetracaine-induced apoptosis.

Conclusions
Tetracaine induces apoptosis of PC12 cells via the MAPK family. ERK activation protects cells from death, but JNK plays the opposite role. Toxic Ca2+ influx caused by tetracaine seems to be responsible for the cell death, but blocking of Na+ channels or L-type Ca2+ channels is unlikely involved in the tetracaine's action for apoptosis.
Isoflurane Causes Anterograde but Not Retrograde Amnesia for Pavlovian Fear Conditioning
Authors: Dutton Robert C. , Maurer Anya J. , Sonner James M. , Fanselow Michael S. , Laster Michael J. , Eger Edmond I 
Published: November 2003

Background
Production of retrograde amnesia by anesthetics would indicate that these drugs can disrupt mechanisms that stabilize memory. Such disruption would allow suppression of memory of previous untoward events. The authors examined whether isoflurane provides retrograde amnesia for classic (Pavlovian) fear conditioning.

Methods
Rats were trained to fear tone by applying three (three-trial) or one (one-trial) tone-shock pairs while breathing various constant concentrations of isoflurane. Immediately after training, isoflurane administration was either discontinued, maintained unchanged, or rapidly increased to 1.0 minimum alveolar concentration for 1 h longer. Groups of rats were similarly trained to fear context while breathing isoflurane by applying shocks (without tones) in a distinctive environment. The next day, memory for the conditioned stimuli was determined by presenting the tone or context (without shock) and measuring the proportion of time each rat froze (appeared immobile). For each conditioning procedure, the effects of the three posttraining isoflurane treatments were compared.

Results
Rapid increases in posttraining isoflurane administration did not suppress conditioned fear for any of the training procedures. In contrast, isoflurane administration during conditioning dose-dependently suppressed conditioning (P < 0.05). Training to tone was more resistant to the effects of isoflurane than training to context (P < 0.05), and the three-trial learning procedure was more was more resistant than the one-trial procedure (P < 0.05).

Conclusions
Isoflurane provided intense dose-dependent anterograde but not retrograde amnesia for classic fear conditioning. Isoflurane appears to disrupt memory processes that occur at or within a few minutes of the conditioning procedure.
Continuous Infraclavicular Brachial Plexus Block for Postoperative Pain Control at Home
Authors: Ilfeld Brian M. , Morey Timothy E. , Enneking F. Kayser 
Published: November 2003

Background
This randomized, double-blinded, placebo-controlled study investigated the efficacy of patient-controlled regional analgesia using an infraclavicular brachial plexus perineural catheter and a portable infusion pump for outpatients undergoing moderately painful, upper extremity orthopedic surgery.

Methods
Preoperatively, patients (n = 30) received an infraclavicular nerve block and perineural catheter. Postoperatively, patients were discharged home with oral narcotics and a portable infusion pump delivering study solution (0.2% ropivacaine or 0.9% saline) via the catheter for 3 days. Investigators and patients were blinded to random group assignment. Daily end points included pain scores at rest and with limb movement, narcotic use and side effects, sleep quality, patient satisfaction, and symptoms of catheter- or local anesthetic-related complications.

Results
Ropivacaine (n = 15) infusion significantly reduced pain compared with saline (n = 15) infusion (P < 0.001). For example, the average pain with movement (scale, 0-10) on postoperative day 1 was 6.1 +/- 2.3 for the saline group versus 2.5 +/- 1.6 for the ropivacaine group (P < 0.001). Oral narcotic use and related side effects were significantly decreased in the ropivacaine group. For example, on postoperative day 1, mean tablet consumption was 5.5 +/- 2.4 and 1.7 +/- 1.6 for the saline and ropivacaine groups, respectively (P < 0.001). Sleep disturbance scores were 10-fold greater for saline administration than for ropivacaine infusion (P < 0.001). Overall satisfaction was significantly greater in the ropivacaine group. No catheter- or local anesthetic-related complications occurred.

Conclusion
After moderately painful orthopedic surgery of the upper extremity, ropivacaine infusion using a portable, mechanical pump and an infraclavicular brachial plexus perineural catheter at home decreased pain, sleep disturbances, narcotic use and related side effects, and improved overall satisfaction.
The Epidural “Top-up”
Authors: Leeda Michal , Stienstra Rudolf , Arbous M. Sesmu , Verschure Maarten J. M. , Dahan Albert , Veering Bernadette Th. , van Kleef Jack W. , Burm Anton G. L. 
Published: November 2003

Background
Extension of sensory blockade after an epidural top-up in combined spinal epidural (CSE) anesthesia is partly attributed to compression of the dural sac by the injected volume. This study investigated whether a volume effect plays a significant role when administering an epidural top-up after an initial epidural loading dose and assessed the predictive value of different factors with respect to the increase in sensory blockade.

Methods
After an epidural loading dose of 75 mg ropivacaine, 0.75%, 30 patients were randomly assigned to one of three groups. After the maximum level of sensory blockade (MLSB) had been established, patients received either an epidural top-up with 10 ml ropivacaine, 0.75% (group 1, n = 10) or saline (group 2, n = 10), or no epidural top-up (group 3, n = 10). Subsequently, sensory blockade was assessed at 5-min intervals for a further 30 min by a blinded observer.

Results
The MLSB increased significantly in the patients receiving an epidural top-up with ropivacaine but not in the patients receiving normal saline. Sensory block extension was inversely related to the number of segments blocked at the time of the epidural top-up, and female gender was associated with a smaller increase in MLSB.

Conclusions
When using epidural ropivacaine, the extension of sensory blockade after administering an epidural top-up is caused by a local anesthetic effect and not by a volume effect. Under the conditions of this study, predictors of the increase in sensory blockade are the presence of ropivacaine in the top-up injectate, the number of segments blocked at the time of epidural top-up, and gender.
Distribution of Local Anesthetic in Axillary Brachial Plexus Block
Authors: Klaastad Øivind , Smedby Örjan , Thompson Gale E. , Tillung Terje , Kristian Hol Per , Røtnes Jan S. , Brodal Per , Breivik Harald , Hetland Karl R. , Fosse Erik T. 
Published: November 2003

Background
There is an unsettled discussion about whether the distribution of local anesthetic is free or inhibited when performing brachial plexus blocks. This is the first study to use magnetic resonance imaging (MRI) to help answer this question.

Methods
Thirteen patients received axillary block by a catheter-nerve stimulator technique. After locating the median nerve, a total dose of 50 ml local anesthetic was injected via the catheter in four divided doses of 1, 4, 15, and 30 ml. Results of sensory and motor testing were compared with the spread of local anesthetic as seen by MRI scans taken after each dose. The distribution of local anesthetic was described with reference to a 20-mm diameter circle around the artery.

Results
Thirty minutes after the last dose, only two patients demonstrated analgesia or anesthesia in the areas of the radial, median, and ulnar nerve. At that time, eight of the patients had incomplete spread of local anesthetic around the artery, as seen by MRI. Their blocks were significantly poorer than those of the five patients with complete filling of the circle, although incomplete blocks were also present in the latter group.

Conclusion
This study demonstrated that MRI is useful in examining local anesthetic distribution in axillary blocks because it can show the correlation between MRI distribution pattern and clinical effect. The cross-sectional spread of fluid around the brachial-axillary artery was often incomplete-inhibited, and the clinical effect often inadequate.
Cerebrospinal Fluid Density Influences Extent of Plain Bupivacaine Spinal Anesthesia
Authors: Schiffer Eduardo , Van Gessel Elisabeth , Fournier Roxane , Weber Anne , Gamulin Zdravko 
Published: November 2003

Background
The attempts to explain the unpredictability of extent of spinal block provided by plain local anesthetic solutions have resulted in many clinical reports; however, causes of this uncertainty are as yet unknown. Recently, normal values of the human cerebrospinal fluid densities have been studied showing important interindividual variations, especially between females and males. The current study was designed to evaluate as primary endpoint the influence of cerebrospinal fluid density values on the extent of spinal block with plain bupivacaine. The ancillary endpoints were search of factors explaining the interindividual differences in cerebrospinal fluid density values reported and determination of the relation between upper extent and regression of spinal anesthesia.

Methods
Sixty-four consecutive patients undergoing peripheral orthopedic surgery with spinal block were enrolled. Spinal anesthesia was performed in the lateral decubitus position with the operated side upward. Two milliliters of cerebrospinal fluid was sampled before injection of 3 ml plain bupivacaine 0.5%. The patient was immediately turned supine and remained in the horizontal position until the end of the study. Maximal sensory block level and time to sensory regression to L4 were determined for each patient enrolled. Cerebrospinal fluid and bupivacaine densities as well as cerebrospinal proteins, glucose, sodium, and chloride concentrations were measured.

Results
A highly significant correlation between cerebrospinal fluid density and maximal sensory block level was found (P = 0.0004). However, this correlation was poorly predictive (R(2) = 0.37). Cerebrospinal fluid density, proteins, and glucose concentrations were significantly higher in men than in women: 1.000567 +/- 0.000091 versus 1.000501 +/- 0.000109 g/ml (P = 0.014), 0.46 +/- 0.18 versus 0.32 +/- 0.13 g/l (P = 0.001), and 3.27 +/- 0.7 versus 2.93 +/- 0.5 mM (P = 0.023), respectively. A highly significant (P = 0.0004) and predictive (R(2) = 0.73) inverse correlation was found between maximal upper sensory extent and sensory regression to L4.

Conclusion
These findings indicate an influence of cerebrospinal fluid density on subarachnoid distribution of 3 ml plain bupivacaine 0.5% and show that with higher cerebrospinal fluid densities, a higher spinal block level can be expected.