bluuebunny/crossref_metadata_2025_split huggingface dataset:
Double-masked Randomized Trial Comparing Alternate Combinations of Intraoperative Anesthesia and Postoperative Analgesia in Abdominal Aortic Surgery
Authors: Norris Edward J. , Beattie Charles , Perler Bruce A. , Martinez Elizabeth A. , Meinert Curtis L. , Anderson Gerald F. , Grass Jeffrey A. , Sakima Neil T. , Gorman Randolph , Achuff Stephen C. , Martin Barbara K. , Minken Stanley L. , Williams G. Melville , Traystman Richard J. 
Published: November 2003

Background
Improvement in patient outcome and reduced use of medical resources may result from using epidural anesthesia and analgesia as compared with general anesthesia and intravenous opioids, although the relative importance of intraoperative versus postoperative technique has not been studied. This prospective, double-masked, randomized clinical trial was designed to compare alternate combinations of intraoperative anesthesia and postoperative analgesia with respect to postoperative outcomes in patients undergoing surgery of the abdominal aorta.

Methods
One hundred sixty-eight patients undergoing surgery of the abdominal aorta were randomly assigned to receive either thoracic epidural anesthesia combined with a light general anesthesia or general anesthesia alone intraoperatively and either intravenous or epidural patient-controlled analgesia postoperatively (four treatment groups). Patient-controlled analgesia was continued for at least 72 h. Protocols were used to standardize perioperative medical management and to preserve masking intraoperatively and postoperatively. A uniform surveillance strategy was used for the identification of prospectively defined postoperative complications. Outcome evaluation included postoperative hospital length of stay, direct medical costs, selected postoperative morbidities, and postoperative recovery milestones.

Results
Length of stay and direct medical costs for patients surviving to discharge were similar among the four treatment groups. Postoperative outcomes were similar among the four treatment groups with respect to death, myocardial infarction, myocardial ischemia, reoperation, pneumonia, and renal failure. Epidural patient-controlled analgesia was associated with a significantly shorter time to extubation (P = 0.002). Times to intensive care unit discharge, ward admission, first bowel sounds, first flatus, tolerating clear liquids, tolerating regular diet, and independent ambulation were similar among the four treatment groups. Postoperative pain scores were also similar among the four treatment groups.

Conclusions
In patients undergoing surgery of the abdominal aorta, thoracic epidural anesthesia combined with a light general anesthesia and followed by either intravenous or epidural patient-controlled analgesia, offers no major advantage or disadvantage when compared with general anesthesia alone followed by either intravenous or epidural patient-controlled analgesia.
An Evaluation of the Quality of Clinical Trials in Anesthesia
Authors: Pua Hwee Leng , Lerman Jerrold , Crawford Mark W. , Wright James G. 
Published: November 2003

Background
The authors evaluated the quality of clinical trials published in four anesthesia journals during the 20-yr period from 1981-2000.

Methods
Trials published in four major anesthesia journals during the periods 1981-1985, 1991-1995, and the first 6 months of 2000 were grouped according to journal and year. Using random number tables, four trials were selected from all of the eligible clinical trials in each journal in each year for the periods 1981-1985 and 1991-1995, and five trials were selected from all of the trials in each journal in the first 6 months of 2000. Methods and results sections from the 160 trials from 1981-1985 and 1991-1995 were randomly ordered and distributed to three of the authors for blinded review of the quality of the study design according to 10 predetermined criteria (weighted equally, maximum score of 10): informed consent and ethics approval, eligibility criteria, sample size calculation, random allocation, method of randomization, blind assessment of outcome, adverse outcomes, statistical analysis, type I error, and type II error. After these trials were evaluated, 20 trials from the first 6 months of 2000 were randomly ordered, distributed, and evaluated as described.

Results
The mean (+/- SD) analysis scores pooled for the four journals increased from 5.5 +/- 1.4 in 1981-1985 to 7.0 +/- 1.1 in 1991-1995 (P < 0.00001) and to 7.8 +/- 1.5 in 2000. For 7 of the 10 criteria, the percentage of trials from the four journals that fulfilled the criteria increased significantly between 1981-1985 and 1991-1995. During the 20-yr period, the reporting of sample size calculation and method of randomization increased threefold to fourfold, whereas the frequency of type I statistical errors remained unchanged.

Conclusion
Although the quality of clinical trials in four major anesthesia journals has increased steadily during the past two decades, specific areas of trial methodology require further attention.
Shiver Suppression Using Focal Hand Warming in Unanesthetized Normal Subjects
Authors: Sweney Matthew T. , Sigg Daniel C. , Tahvildari Samira , Iaizzo Paul A. 
Published: November 2003

Background
A decrease of 1 or 2 degrees C in core temperature may provide protection against cerebral ischemia. However, during corporeal cooling of unanesthetized patients, the initiation of involuntary motor activity (shiver) prevents the reduction of core temperature. The authors' laboratory previously showed that focal facial warming suppressed whole-body shiver. The aim of the current study was to determine whether the use of hand warming alone could suppress shiver in unanesthetized subjects and hence potentiate core cooling.

Methods
Subjects (n = 8; healthy men) were positioned supine on a circulating water mattress (8-15 degrees C) with a convective-air coverlet (14 degrees C) extending from their necks to their feet. A dynamic protocol was used in which focal hand warming was used to suppress involuntary motor activity, enabling noninvasive cooling to decrease core temperatures. The following parameters were monitored: (1) heart rate; (2) blood pressure; (3) core temperature (rectal, tympanic); (4) cutaneous temperature and heat flux; (5) subjective shiver level (SSL scale 0-10) and thermal comfort index (scale 0-10); (6) metabolic data (n = 6); and (7) electromyograms.

Results
During cooling without hand warming, involuntary motor activity increased until it was widespread. After subjects reported whole-body shiver (SSL > or = 7), applied hand warming, in all cases, reduced shiver levels (SSL < o r= 3), decreased electromyographic root mean square amplitudes, and allowed core temperature to decrease from 37.0 +/- 0.2 to 35.9 +/- 0.5 degrees C (measured rectally).

Conclusions
Focal hand warming seems to be valuable in minimizing or eliminating the need to suppress involuntary motor activity pharmacologically when it is desired to induce or maintain mild hypothermia; it may be used in conjunction with facial warming or in cases in which facial warming is contraindicated.
Activation of Coagulation and Fibrinolysis during Coronary Surgery
Authors: Casati Valter , Gerli Chiara , Franco Annalisa , Della Valle Patrizia , Benussi Stefano , Alfieri Ottavio , Torri Giorgio , D’Angelo Armando 
Published: November 2003

Background
The authors studied the changes in selected hemostatic variables in patients undergoing coronary surgery with on-pump coronary artery bypass grafting (CABG) or off-pump coronary artery bypass surgery (OPCAB) techniques.

Methods
Platelet counts and plasma concentrations of antithrombin, fibrinogen, D dimer, alpha(2) antiplasmin, and plasminogen were measured preoperatively, 5 min after administration of heparin, 10 min after arrival in the intensive care unit, and 24 h after surgery in patients scheduled to undergo OPCAB (n = 15) or CABG (n = 15). To correct for dilution, hemostatic variables and platelet counts were adjusted for the changes in immunoglobulin G plasma concentrations and hematocrit, respectively.

Results
Adjusting for dilution, antithrombin and fibrinogen concentrations decreased to a similar extent in patients undergoing OPCAB or CABG (pooled means and 95% confidence limits of the mean: 95.5% of baseline, 93-98%, P = 0.002, and 91.7% of baseline, 88-95%, P = 0.0001), respectively, whereas alpha(2)-antiplasmin concentrations were unchanged. Only CABG was associated with a reduction in platelet counts (76% of baseline, 66-85%, P = 0.0001), plasminogen concentrations (96% of baseline, 91-99%, P = 0.011), and increased D-dimer formation (476%, 309-741%, P = 0.004). Twenty-four hours after surgery, platelet counts were still lower in patients undergoing CABG (P = 0.049), but all the investigated variables adjusted for dilution were similar in the two groups.

Conclusions
Coronary surgery causes a net consumption of antithrombin and fibrinogen. A transient decrease in platelet counts, with plasminogen activation and increased D-dimer formation, however, is only observed with CABG. Twenty-four hours after surgery, the hemostatic profiles of patients in both groups are similar.
Prospective Randomized Trial of Normothermic versus Hypothermic Cardiopulmonary Bypass on Cognitive Function after Coronary Artery Bypass Graft Surgery
Authors: Grigore Alina M. , Mathew Joseph , Grocott Hilary P. , Reves Joseph G. , Blumenthal James A. , White William D. , Smith Peter K. , Jones Robert H. , Kirchner Jerry L. , Mark Daniel B. , Newman Mark F. 
Published: November 2003

Background
Despite significant advances in cardiopulmonary bypass (CPB) technology, surgical techniques, and anesthetic management, central nervous system complications occur in a large percentage of patients undergoing surgery requiring CPB. Many centers are switching to normothermic CPB because of shorter CPB and operating room times and improved myocardial protection. The authors hypothesized that, compared with normothermia, hypothermic CPB would result in superior neurologic and neurocognitive function after coronary artery bypass graft surgery.

Methods
Three hundred patients undergoing elective coronary artery bypass graft surgery were prospectively enrolled and randomly assigned to either normothermic (35.5-36.5 degrees C) or hypothermic (28-30 degrees C) CPB. A battery of neurocognitive tests was performed preoperatively and at 6 weeks after surgery. Four distinct cognitive domains were identified and standardized using factor analysis and were then compared on a continuous scale.

Results
Two hundred twenty-seven patients participated in 6-week follow-up testing. There were no differences in neurologic or neurocognitive outcomes between normothermic and hypothermic groups in multivariable models, adjusting for covariable effects of baseline cognitive function, age, and years of education, as well as interaction of these with temperature treatment.

Conclusions
Hypothermic CPB does not provide additional central nervous system protection in adult cardiac surgical patients who were maintained at either 30 or 35 degrees C during CPB.
Coronary Artery Plaque Burden and Perioperative Cardiac Risk
Authors: Mahla Elisabeth , Vicenzi Martin N. , Schröttner Brigitte , Maier Robert , Tiesenhausen Kurt , Watzinger Norbert , Rienmüller Rainer , Moser Rita L. , Metzler Helfried 
Published: November 2003

Background
Electron-beam computed tomography-derived coronary calcium score correlates with the morphologic severity of coronary artery disease, reflecting both global atherosclerotic plaque formation and coronary artery luminal narrowing. The current study examines the impact of coronary atherosclerotic plaque burden, measured by coronary calcium score, on the potential for perioperative myocardial cell injury, as assessed by cardiac troponin T elevations in patients undergoing elective vascular surgery. The authors further investigated whether perioperative myocardial cell injury in those patients adversely affects noninvasive measures of left ventricular systolic function, such as ejection fraction and wall motion score.

Methods
Fifty-one consecutive patients scheduled for vascular surgery were enrolled in this prospective study. In addition to standard preoperative evaluation, including patient history and physical examination, electron-beam computed tomography scan, 12-lead electrocardiography, and transthoracic echocardiography were performed on the day before surgery. Subsequent evaluations on postoperative days 2 and 7 included transthoracic echocardiography and 12-lead electrocardiography. Cardiac troponin T determinations were performed on the day before surgery, immediately preoperatively, and on postoperative days 1, 2, 3, and 7.

Results
The median coronary calcium score of the 51 patients was 997.0 (25th percentile, 202.5; 75th percentile, 1,949.5). Cardiac troponin T elevations exclusively occurred in patients with a coronary calcium score greater than 1,000. The six patients (12%) with perioperative cardiac troponin T elevations had a 2.5-fold higher coronary calcium score than those without cardiac troponin T elevation (P = 0.021). In these patients, the ejection fraction decreased from 61 +/- 10% to 52 +/- 13% (mean +/- SD) on postoperative day 2 and was 54 +/- 16% on postoperative day 7 (P = 0.022).

Conclusion
A high electron-beam computed tomography coronary calcium score, reflecting substantial coronary plaque burden, carries an increased risk for myocardial cell injury after vascular surgery. In these patients, myocardial damage may result in deterioration of global systolic left ventricular function.
Wavelet Analysis of Middle Latency Auditory Evoked Responses
Authors: Kochs Eberhard , Stockmanns Gudrun , Thornton Christine , Nahm Werner , Kalkman Cor J. 
Published: November 2003

Background
Middle latency auditory evoked responses (MLAER) as a measure of depth of sedation are critically dependent on data quality and the analysis technique used. Manual peak labeling is subject to observer bias. This study investigated whether a user-independent index based on wavelet transform can be derived to discriminate between awake and unresponsive states during propofol sedation.

Methods
After obtaining ethics committee approval and written informed consent, 13 volunteers and 40 patients were studied. In all subjects, propofol was titrated to loss of response to verbal command. The volunteers were allowed to recover, then propofol was titrated again to the same end point, and subjects were finally allowed to recover. From three MLAER waveforms at each stage, latencies and amplitudes of peaks Pa and Nb were measured manually. In addition, wavelet transform for analysis of MLAER was applied. Wavelet transform gives both frequency and time information by calculation of coefficients related to different frequency contents of the signal. Three coefficients of the so-called wavelet detail level 4 were transformed into a single index (Db3d4) using logistic regression analysis, which was also used for calculation of indices for Pa, Nb, and Pa/Nb latencies. Prediction probabilities for discrimination between awake and unresponsive states were calculated for all MLAER indices.

Results
During propofol infusion, subjects were unresponsive, and MLAER components were significantly depressed when compared with the awake states (P < 0.001). The wavelet index Db3d4 was positive for awake and negative for unresponsive subjects with a prediction probability of 0.92.

Conclusion
These data show that automated wavelet analysis may be used to differentiate between awake and unresponsive states. The threshold value for the wavelet index allows easy recognition of awake versus unresponsive subjects. In addition, it is independent of subjective peak identification and offers the advantage of easy implementation into monitoring devices.
Bispectral Index Monitoring during Sedation with Sevoflurane, Midazolam, and Propofol
Authors: Ibrahim Andra E. , Taraday Julie K. , Kharasch Evan D. 
Published: November 2003

Background
Bispectral Index (BIS) has been used to measure sedation depth. Ideally, to guide anesthetic management, range of BIS scores at different sedation levels should not overlap, and BIS should be independent of drug used. This study assessed ability of BIS to predict sedation depth between sevoflurane, propofol, and midazolam. Quality of recovery was also compared.

Methods
Patients undergoing surgery with local or regional anesthesia and sedation were randomized to sevoflurane (n = 23), midazolam (n = 21), or propofol (n = 22). Sedation was titrated to Observers's Assessment of Alertness-Sedation score of 3 (responds slowly to voice). BIS and Observers's Assessment of Alertness-Sedation were measured every 5 min. BIS prediction probability (PK) was compared between drugs. Recovery was assessed by BIS and Digit Symbol Substitution and memory tests.

Results
Bispectral Index of responders to voice was significantly different from nonresponders (86 +/- 10 vs. 74 +/- 14, mean +/- SD; P < 0.001) However, wide variability and overlap in BIS were observed (25th-75th percentile, responders vs. non-responders: 79-96 vs. 65-83). BIS of responders was different for sevoflurane versus propofol and midazolam. BIS was a better predictor of propofol sedation than sevoflurane or midazolam (PK = 0.87 +/- 0.11, 0.76 +/- 0.01, and 0.69 +/- 0.02, respectively; P < 0.05). At 10 min after the procedure, 76, 48, and 24% of sevoflurane, propofol, midazolam patients, respectively, returned to baseline Digit Symbol Substitution scores (P < 0.05). Excitement-disinhibition occurred in 70, 36, and 5% of sevoflurane, propofol, and midazolam patients, respectively (P < 0.05).

Conclusion
Individual BIS scores demonstrate significant variability, making it difficult to predict sedation depth. The relation between BIS and sedation depth may not be independent of anesthetic agent. Quality of recovery was similar between drugs, but excitement occurred frequently with sevoflurane.
The Effects of Aprotinin on Thromboelastography with Three Different Activators
Authors: Avidan Michael S. , Da Fonseca Jorge , Parmar Kiran , Alcock Emma , Ponte José , Hunt Beverley J. 
Published: November 2003

Background
Thromboelastography is used for assessment of hemostasis. Adherence to thromboelastography-guided algorithms and aprotinin administration each decrease bleeding and blood product usage after cardiac surgery. Aprotinin, through inhibition of kallikrein, causes prolongation of the celite-activated clotting time and the activated partial thromboplastin ratio. The aim of this study was to assess the effects of aprotinin on the thromboelastography trace.

Methods
Three activators were used in the thromboelastography: celite (which is widely established), kaolin, and tissue factor. Assessment was performed on blood from volunteers and from patients before and after cardiac surgery.

Results
The tissue factor-activated thromboelastography trace was unaffected by the addition of aprotinin. When celite and kaolin were used as activators in the presence of aprotinin, the reaction time (time to clot formation) of the thromboelastography trace was prolonged (P < 0.0001) and the maximum amplitude (clot strength) was decreased (P < 0.05). With celite as an activator, the addition of aprotinin decreased (P < 0.05) the thromboelastography alpha angle (rate of clot extension). The reaction time of the celite-activated trace correlated with the activated partial thromboplastin ratio (P < 0.01). The reaction time of the tissue factor-activated trace correlated with the international normalized ratio (P < 0.01).

Conclusion
The thromboelastography trace is altered in the presence of aprotinin when celite and kaolin are used as activators but not when tissue factor is the activator.
Influence of Voltage-sensitive Ca++Channel Drugs on Bupivacaine Infiltration Anesthesia in Mice
Authors: Smith Forrest L. , Davis Richard W. , Carter Richard 
Published: November 2003

Background
Local anesthesia has been traditionally associated with blockade of voltage-sensitive sodium (Na(+)) channels. Yet in vitro evidence indicates that local anesthetic mechanisms are more complex than previously understood. For example, local anesthetics bind and allosterically modify 1,4-dihydropyridine-sensitive Ca(++) channels and can reduce Ca(++) influx in tissues. The current study examines the influence of voltage-sensitive Ca(++) channels in bupivacaine infiltration anesthesia.

Methods
Baseline tail-flick latencies to radiant heat nociception were obtained before subcutaneous infiltration of bupivacaine and Ca(++)-modulating drugs in the tails of mice. No musculature is contained in the tail that could result in motor block. The magnitude of infiltration anesthesia over time, as well as the potency of bupivacaine alone or in the presence of Ca(++)-modulating drug, was assessed by obtaining test latencies.

Results
The 1,4-dihydropyridine L-type Ca(++) channel agonist S(-)-BayK-8644 reduced the duration of action and potency of bupivacaine anesthesia. In opposite fashion, nifedipine and nicardipine increased the effects of bupivacaine. Neither nifedipine nor nicardipine alone elicited anesthesia. Alternatively, the phenylalkylamine L-type blocker verapamil elicited concentration-dependent anesthesia. Other Ca(++) channel subtype blockers were investigated as well. The N-, T-, P-, and Q-type channel blockers, omega-conotoxin GVIA, flunarizine, omega-agatoxin IVA, and omega-conotoxin MVIIC, respectively, were unable to modify bupivacaine anesthesia.

Conclusions
These results indicate that heat nociception stimulates Ca(++) influx through L-type channels on nociceptors in skin. Although other voltage-sensitive Ca(++) channels may be located on skin nociceptors, only the L-type channel drugs affected bupivacaine in the radiant heat test.
Local Anesthetic Properties of Prenylamine
Authors: Mujtaba Mustafa G. , Gerner Peter , Kuo Wang Ging 
Published: November 2003

Background
Local anesthetics that produce analgesia of long duration with minimal impairment of autonomic functions are highly desirable for pain management in the clinic. Prenylamine is a known calcium channel blocker, but its local anesthetic blocking effects on voltage-gated sodium channels have not been studied thus far.

Methods
The authors characterized the tonic and use-dependent prenylamine block of native Na(+) channels in cultured rat neuronal GH3 cells during whole cell voltage clamp conditions and the local anesthetic effect of prenylamine by neurologic evaluation of sensory and motor functions of sciatic nerve during neural block in rats.

Results
Prenylamine elicits both use-dependent block of Na(+) channels during repetitive pulses (3 microm prenylamine produced 50% block at 5 Hz) and tonic block for both resting and inactivated Na(+) channels. The 50% inhibitory concentration for prenylamine was 27.6 +/- 1.3 microm for resting channels and 0.75 +/- 0.02 microm for inactivated channels. Furthermore, in vivo data show that 10 mm prenylamine produced a complete sciatic nerve block of motor function, proprioceptive responses, and nociceptive responses that lasted approximately 27, 34, and 24 h, respectively. Rats injected with 15.4 mm bupivacaine, a known local anesthetic currently used for pain management, had a significantly shorter duration of blockade (< 2 h) compared with rats injected with prenylamine.

Conclusions
The data presented here demonstrate that prenylamine possesses local anesthetic properties in vitro and elicits prolonged local anesthesia in vivo.