bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lung Function under High Thoracic Segmental Epidural Anesthesia with Ropivacaine or Bupivacaine in Patients with Severe Obstructive Pulmonary Disease Undergoing Breast Surgery
Authors: Groeben Harald , Schäfer Beatrix , Pavlakovic Goran , Silvanus Marie-Theres , Peters Juergen 
Published: August 2004

Background
Because general anesthesia with tracheal intubation can elicit life-threatening bronchospasm in patients with bronchial hyperreactivity, epidural anesthesia is often preferred. However, segmental high thoracic epidural anesthesia (sTEA) causes pulmonary sympathetic and respiratory motor blockade. Whether it can be safely used for chest wall surgery as a primary anesthetic technique in patients with chronic obstructive pulmonary disease or asthma is unclear. Furthermore, ropivacaine supposedly evokes less motor blockade than bupivacaine and might minimize side effects. To test the feasibility of the technique and the hypotheses that (1) sTEA with ropivacaine or bupivacaine does not change lung function and (2) there is no difference between sTEA with ropivacaine or bupivacaine, the authors studied 20 patients with severe chronic obstructive pulmonary disease (forced expiratory volume in 1 s [FEV1] = 52.1 +/- 17.3% of predicted [mean +/- SD]) or asthma who were undergoing breast surgery.

Methods
In a double-blind, randomized fashion, sTEA was performed with 6.6 +/- 0.5 ml of either ropivacaine, 0.75% (n = 10), or bupivacaine, 0.75% (n = 10). FEV1, vital capacity, FEV1 over vital capacity, spread of analgesia (pin prick), hand and foot skin temperatures, mean arterial pressure, heart rate, and local anesthetic plasma concentrations were measured with patients in the sitting and supine positions before and during sTEA.

Results
Segmental high thoracic epidural anesthesia (segmental spread C4-T8 [bupivacaine] and C5-T9 [ropivacaine]) significantly decreased FEV1 from 1.22 +/- 0.54 l (supine) to 1.09 +/- 0.56 l (ropivacaine) and from 1.23 +/- 0.49 l to 1.12 +/- 0.46 l (bupivacaine). In contrast, FEV1 over vital capacity increased from 64.6 +/- 13.5 to 68.2 +/- 14.5% (ropivacaine) and from 62.8 +/- 12.4 to 66.5 +/- 13.6% (bupivacaine). There was no difference between ropivacaine and bupivacaine. Skin temperatures increased significantly, whereas arterial pressure and heart rate significantly decreased indicating widespread sympathetic blockade. All 20 patients tolerated surgery well.

Conclusions
Despite sympathetic blockade, sTEA does not increase airway obstruction and evokes only a small decrease in FEV1 as a sign of mild respiratory motor blockade with no difference between ropivacaine and bupivacaine. Therefore, sTEA can be used in patients with severe chronic obstructive pulmonary disease and asthma undergoing chest wall surgery as an alternative technique to general anesthesia.
Implicit Memory for Words Played during Isoflurane- or Propofol-based Anesthesia
Authors: Münte Sinikka , Schmidt Maren , Meyer Maren , Nager Wido , Lüllwitz Ekkehard , Münte Thomas F. , Piepenbrock Siegfried 
Published: August 2004

Background
Unconscious processing of words during general anesthesia has been suggested after surgery with several tests of implicit memory. Patients can neither recall those words nor do they have explicit memories of other intraoperative events. It is unclear to what degree information is processed during general anesthesia and which tests are best suited to detect implicit memory. In the current study, a lexical decision paradigm not previously used to demonstrate implicit memory during anesthesia was used.

Methods
Sixty patients undergoing lumbar disc surgery were assigned to receive isoflurane infusion- or propofol infusion-based anesthesia combined with alfentanil infusions and a nitrous oxide-oxygen mixture. A control group of 10 medical students listened to tapes without receiving anesthesia. Two tapes, each containing a list of 30 low-frequency German nouns repeated for 15 min, were prepared, with half of the patients listening to tape A and the other half listening to tape B during the operation. Exposure time was 15 min from the time of skin incision onward. In the test phase, approximately 7 h later, words from lists A and B plus 60 nonwords were presented in random order by a computer program. Subjects were asked to indicate, by pressing one of two response buttons, whether the spoken word was or was not a legal German word (lexical decision).

Results
A recognition test revealed chance recognition for words presented during anesthesia. Lexical decision responses, however, were slightly faster to primed (previously presented) words than to unprimed (not previously presented) words when the entire group of patients was tested, suggesting a small implicit memory effect, which barely failed to reach the significance level. When the two medication groups were tested separately, no significant implicit memory effect could be ascertained statistically. The effects of previous exposure were much more pronounced in the control group.

Conclusions
Balanced anesthesia techniques with isoflurane or propofol lead to only a minimal, statistically borderline implicit memory effect in the lexical decision paradigm.
The Diverse Actions of Volatile and Gaseous Anesthetics on Human-cloned 5-Hydroxytryptamine3Receptors Expressed in Xenopus Oocytes
Authors: Suzuki Takahiro , Koyama Hideki , Sugimoto Masahiro , Uchida Ichiro , Mashimo Takashi 
Published: August 2004

Background
General anesthetics can modulate the 5-hydroxytryptamine type 3 (5-HT3) receptor, which may be involved in processes mediating nausea and vomiting, and peripheral nociception. The effects of the new volatile anesthetic sevoflurane and the gaseous anesthetics nitrous oxide (N2O) and xenon (Xe) on the 5-HT3 receptor have not been well-characterized.

Methods
Homomeric human-cloned 5-HT3A receptors were expressed in Xenopus oocytes. The effects of halothane, isoflurane, sevoflurane, N2O, and Xe on 5-HT-induced currents were studied using a two-electrode, voltage clamping technique.

Results
Halothane (1%) and isoflurane (1%) potentiated 1 mum 5-HT-induced currents to 182 +/- 12 and 117 +/- 2%, respectively. In contrast, sevoflurane (1%), N2O (70%), and Xe (70%) inhibited 5-HT-induced currents to 76 +/- 1, 77 +/- 4, and 34 +/- 4%, respectively. The inhibitory effects were noncompetitive for sevoflurane and competitive for N2O and Xe. None of these inhibitory effects showed voltage dependency.

Conclusion
Inhalational general anesthetics produce diverse effects on the 5-HT3 receptor. Both halothane and isoflurane enhanced 5-HT3 receptor function in a concentration-dependent manner, which is consistent with previous studies. Sevoflurane inhibited the 5-HT3 receptor noncompetitively, whereas N2O and Xe inhibited the 5-HT3 receptor competitively, suggesting the inhibitory mechanism of sevoflurane might be different from those of N2O and Xe.
Sigh Improves Gas Exchange and Lung Volume in Patients with Acute Respiratory Distress Syndrome Undergoing Pressure Support Ventilation
Authors: Patroniti Nicoló , Foti Giuseppe , Cortinovis Barbara , Maggioni Elena , Bigatello Luca M. , Cereda Maurizio , Pesenti Antonio 
Published: August 2004

Background
The aim of our study was to assess the effect of periodic hyperinflations (sighs) during pressure support ventilation (PSV) on lung volume, gas exchange, and respiratory pattern in patients with early acute respiratory distress syndrome (ARDS).

Methods
Thirteen patients undergoing PSV were enrolled. The study comprised 3 steps: baseline 1, sigh, and baseline 2, of 1 h each. During baseline 1 and baseline 2, patients underwent PSV. Sighs were administered once per minute by adding to baseline PSV a 3- to 5-s continuous positive airway pressure (CPAP) period, set at a level 20% higher than the peak airway pressure of the PSV breaths or at least 35 cm H2O. Mean airway pressure was kept constant by reducing the positive end-expiratory pressure (PEEP) during the sigh period as required. At the end of each study period, arterial blood gas tensions, air flow and pressures traces, end-expiratory lung volume (EELV), compliance of respiratory system (Crs), and ventilatory parameters were recorded.

Results
Pao2 improved (P < 0.001) from baseline 1 (91.4 +/- 27.4 mmHg) to sigh (133 +/- 42.5 mmHg), without changes of Paco2. EELV increased (P < 0.01) from baseline 1 (1,242 +/- 507 ml) to sigh (1,377 +/- 484 ml). Crs improved (P < 0.01) from baseline 1 (40.2 +/- 12.5 ml/cm H2O) to sigh (45.1 +/- 15.3 ml/cm H2O). Tidal volume of pressure-supported breaths and the airway occlusion pressure (P0.1) decreased (P < 0.01) during the sigh period. There were no significant differences between baselines 1 and 2 for all parameters.

Conclusions
The addition of 1 sigh per minute during PSV in patients with early ARDS improved gas exchange and lung volume and decreased the respiratory drive.
Effects of Dexamethasone on Intravascular and Extravascular Fluid Balance in Patients Undergoing Coronary Bypass Surgery with Cardiopulmonary Bypass
Authors: von Spiegel Tilman , Giannaris Savvas , Wietasch Götz J. K. , Schroeder Stefan , Buhre Wolfgang , Schorn Bernd , Hoeft Andreas 
Published: August 2004

Background
Cardiac surgery with cardiopulmonary bypass is often associated with postoperative hemodynamic instability. In this regard beneficial effects of corticosteroids are known. The purpose of this study was to investigate whether these effects are due mainly to a modification of the intravascular and extravascular volume status or whether a more direct improvement of cardiovascular performance by corticosteroids is the underlying mechanism.

Methods
Twenty patients undergoing elective coronary bypass grafting were included in this randomized double-blind study. Patients of the treatment group received 1 mg/kg-1 dexamethasone after induction of anesthesia. In addition to the use of standard monitors and detailed fluid balance assessments, the transpulmonary double-indicator technique was used to measure extravascular lung water, total blood volume, and intrathoracic blood volume. Measurements were done after induction of anesthesia and 1 h, 6 h, and 20 h after the end of surgery.

Results
After cardiopulmonary bypass, no relevant increase in extravascular lung water was observed, despite highly positive fluid balances in all patients. A significantly smaller increase in extravascular fluid content was observed in the dexamethasone group. Total blood volume and intrathoracic blood volume did not differ in the two groups. Patients pretreated with dexamethasone had a decreased requirement for vasoactive substances and, in contrast with the control group, no increase in pulmonary artery pressure.

Conclusions
Extravascular fluid but not extravascular lung water is increased in patients after surgery with cardiopulmonary bypass. Pretreatment of adult patients with 1 mg/kg-1 dexamethasone before coronary bypass grafting decreases extravascular fluid gain and seems to improve postoperative cardiovascular performance. This effect is not caused by a better intravascular volume status.
Standard versus Fiberoptic Pulmonary Artery Catheterization for Cardiac Surgery in the Department of Veterans Affairs
Authors: London Martin J. , Moritz Thomas E. , Henderson William G. , Sethi Gulshan K. , O'Brien Maureen M. , Grunwald Gary K. , Beckman Catherine B. , Shroyer A. Laurie , Grover Frederick L. 
Published: August 2004

Background
Controversy exists regarding the utility of continuous monitoring of mixed venous oxygen saturation (STvo2) during cardiac surgery. During a multicenter, prospective, observational study in the Department of Veterans Affairs (Cooperative Study #5), frequency of use of standard pulmonary artery catheterization (PAC) and STvo2-PAC was recorded. Here the authors relate these data to clinical outcomes.

Methods
Logistic and Cox regression models evaluating the association of PAC type with mortality, one or more postoperative complications, cardiac complications, time to extubation, and intensive care unit length of stay were constructed. The number of thermodilution cardiac outputs and arterial blood gas analyses performed in the first 24 h postoperatively were compared.

Results
Data from 3,265 patients undergoing myocardial revascularization (81.7%) or valve replacement-repair (18.3%) were considered. STvo2-PAC was used in 49% and PAC in 51% of patients. In the 14 hospitals, STvo2-PAC was used in all patients in four, in some patients in four, and never in six. No association of STvo2-PAC use with outcome were observed aside from unexplained hospital level effects. A small but statistically significant reduction in the number of arterial blood gas analyses (8 +/- 3 vs. 10 +/- 4, P < 0.0001, STvo2-PAC vs. PAC, respectively) and thermodilution cardiac outputs (14 +/- 8 vs. 15 +/- 9, P < 0.0001, STvo2-PAC vs. PAC, respectively) was observed with use of STvo2-PAC.

Conclusions
Despite higher cost, STvo2-PAC was commonly used in this cohort. Our analysis failed to detect associations with improved outcomes aside from a small reduction in resource utilization. The precise role of STvo2-PAC remains uncertain.
Comparison of Acustimulation and Ondansetron for the Treatment of Established Postoperative Nausea and Vomiting
Authors: Coloma Margarita , White Paul F. , Ogunnaike Babatunde O. , Markowitz Scott D. , Brown Philip M. , Lee Alex Q. , Berrisford Sally B. , Wakefield Cynthia A. , Issioui Tijani , Jones Stephanie B. , Jones Daniel B. 
Published: August 2004

Background
This study was designed to evaluate transcutaneous electrical acupoint stimulation (acustimulation) using the ReliefBand compared with ondansetron for the treatment of established postoperative nausea and vomiting (PONV) after outpatient laparoscopic surgery.

Methods
After the authors obtained institutional review board approval and written informed consent, 268 outpatients were enrolled in this randomized, double-blind, placebo- and sham-controlled study. All patients received antiemetic prophylaxis with metoclopramide, 10 mg intravenously, or droperidol, 0.625 mg intravenously, after induction of anesthesia. A total of 90 patients developed PONV in the recovery units and were randomized to one of three treatment groups: (1) the ondansetron group received 4 mg intravenous ondansetron and a sham ReliefBand; (2) the acustimulation group received 2 ml intravenous saline and a ReliefBand; and (3) the combination group received 4 mg intravenous ondansetron and a ReliefBand. A rescue antiemetic (10 mg intravenous metoclopramide) was administered only if the PONV symptoms persisted for 15 min or longer after initiating the treatment. A blinded observer recorded the recovery times, emetic symptoms, rescue antiemetics, maximum nausea scores, complete response to study treatment, and time to achieve discharge criteria. Postdischarge side effects, as well as patient satisfaction and quality of recovery scores, were assessed at 24 and 72 h after surgery.

Results
The combination group had a significantly higher complete response rate than the acustimulation group (73% vs.40%, P <0.01). In addition, fewer patients (8 vs. 18) in the combination (vs. acustimulation) group experienced subsequent emetic events (P < 0.03). However, there were no significant differences between the three groups with respect to patient satisfaction and quality of recovery scores.

Conclusions
Acustimulation with the ReliefBand can be used as an alternative to ondansetron for the treatment of established PONV. However, the use of ondansetron (4 mg intravenously) in combination with the ReliefBand device improved the complete response rate to the acustimulation therapy.
Effect of Local Anesthetic on Neuronal Cytoplasmic Calcium and Plasma Membrane Lysis (Necrosis) in a Cell Culture Model
Authors: Johnson Michael E. , Saenz J. Armando , DaSilva Assir Daniel , Uhl Cindy B. , Gores Gregory J. 
Published: August 2004

Background
To investigate the mechanism by which rare cases of spinal local anesthetic (LA) neurotoxicity occur, we have tested the hypotheses that LAs elevate cytoplasmic calcium (Ca2+(cyt)), that this is associated with a neurotoxic effect, and that lidocaine and bupivacaine differ in their neurotoxicity.

Methods
Neurons of the ND7 cell culture line, derived from dorsal root ganglion, were loaded with fura-2 and analyzed by digitized video fluorescence microscopy during 60 min LA exposure, allowing determination of Ca2+(cyt) and time of necrotic cell death (plasma membrane lysis) at the single neuron level.

Results
Lidocaine 0.1% and bupivacaine 0.025% caused minimal changes in Ca. Lidocaine 0.5-5% and bupivacaine 0.125-0.625% caused an early, small (less than threefold), concentration-dependent increase in Ca2+(cyt) that was transient and returned to near baseline within 10 min. Lidocaine 2.5% and 5% then caused a sustained, greater than ten-fold increase in Ca2+(cyt) and death in some neurons during the 60 min exposure period. Pretreatment with thapsigargin eliminated the initial transient increase in Ca2+(cyt), consistent with endoplasmic reticulum (ER) as its source, and increased neuronal death with 5% lidocaine, suggesting that lidocaine neurotoxicity can be increased by failure of ER to take up elevated Ca2+(cyt). The later sustained increase in Ca2+(cyt) seen with 2.5 and 5% lidocaine was prevented in Ca2+ -free medium, and restored when Ca2+ was added back to the buffer in the presence of lidocaine, suggesting that higher concentrations of lidocaine increase influx of Ca2+ through the plasma membrane.

Conclusions
In this model, lidocaine greater than 2.5% elevates Ca2+(cyt) to toxic levels. Bupivacaine and lower concentrations of lidocaine transiently alter Ca2+(cyt) homeostasis for several minutes, but without an immediate neurotoxic effect within 60 min.
Myocardial Effects of Halothane and Isoflurane in Senescent Rats
Authors: Rozenberg Sandrine , Besse Sophie , Vivien Benoît , Coriat Pierre , Riou Bruno 
Published: August 2004

Background
Aging is associated with marked alterations in myocardial contraction and relaxation, whereas halogenated anesthetics depress myocardial contractility. However, their effects on aging myocardium are unknown.

Methods
Mechanical variables of left ventricular papillary muscles from adult and senescent rats (29 degrees C; pH 7.40; Ca2+ 1.0 or 0.5 mM; stimulation frequency, 12 pulses/min) were studied. The expression of genes coding for the alpha and beta-myosin heavy chain (MHC) and Ca2+ -ATPase of the sarcoplasmic reticulum (SR) were studied. The effects of halothane and isoflurane were studied. The inotropic effects were compared under low and high loads, using the maximum unloaded shortening velocity (Vmax) and maximum isometric active force (AF). The lusitropic effects were compared in isotonic and isometric conditions.

Results
Senescent rats had a decrease in contraction and relaxation velocities, associated with a reexpression of beta-MHC mRNAs and a decrease in SR Ca2+ -ATPase mRNAs. Halothane induced a lower negative inotropic effect in senescent rats (1.5 vol%, AF: 53 +/- 14% vs. 39 +/- 12% of baseline values; P < 0.01) whereas isoflurane induced a similar negative inotropic effect (1.5 vol%, AF: 81 +/- 7% vs. 87 +/- 7% of baseline values; NS). Halothane induced a negative lusitropic effect in isotonic conditions in adult, but not in senescent, rats.

Conclusions
The inotropic and lusitropic effects of halothane were less important in senescent than in adult rats, whereas the effects of isoflurane were similar. These differences are probably related to differences in SR function and in the effects of halogenated anesthetics on the SR.
General Anesthetics Do Not Affect Release of the Neuropeptide Cholecystokinin from Isolated Rat Cortical Nerve Terminals
Authors: Pashkov Victor N. , Westphalen Robert I. , Hemmings Hugh C. 
Published: August 2004

Background
General anesthetics inhibit evoked release of classic neurotransmitters. However, their actions on neuropeptide release in the central nervous system have not been well characterized.

Methods
The effects of representative intravenous and volatile anesthetics were studied on the release of sulfated cholecystokinin 8 (CCK8s), a representative excitatory neuropeptide, from isolated rat cerebrocortical nerve terminals (synaptosomes). Basal, elevated KCl depolarization-evoked and veratridine-evoked release of CCK8s from synaptosomes purified from rat cerebral cortex was evaluated at 35 degrees C in the absence or presence of extracellular Ca2+. CCK8s released into the incubation medium was determined by enzyme-linked immunoassay after filtration.

Results
Elevation of extracellular KCl concentration (to 15-30 mM) or veratridine (10-20 microm) stimulated Ca2+ -dependent CCK8s release. Basal, elevated KCl- or veratridine-evoked CCK8s release was not affected significantly by propofol (12.5-50 microm), pentobarbital (50 and 100 microm), thiopental (20 microm), etomidate (20 microm), ketamine (20 microm), isoflurane (0.6-0.8 mM), or halothane (0.6-0.8 mMm).

Conclusions
Clinically relevant concentrations of several classes of general anesthetics did not affect basal, KCl-evoked, or veratridine-evoked CCK8s release from isolated rat cortical nerve terminals. This is in contrast to the demonstrable effects of certain general anesthetics on the release of amino acid and catecholamine transmitters. These transmitter-specific presynaptic effects of general anesthetics suggest that anesthetic-sensitive presynaptic targets are not common to all transmitter classes.
Mechanisms of Postoperative Pain: Clinical Indications for a Contribution of Central Neuronal Sensitization
Authors: Dirks Jesper , Møiniche Steen , Hilsted Karen-Lisa , Dahl Jørgen B. 
Published: August 2004

Background
The relative importance of different nociceptive mechanisms for the intensity, duration, and character of postoperative pain is not well established. It has been suggested that sensitization of dorsal horn neurones may contribute to pain in the postoperative period. We hypothesized that wound hyperalgesia in postoperative patients and experimentally heat-induced secondary hyperalgesia share a common mechanism, sensitization of central neurones, and consequently, that the short-acting opioid remifentanil would have comparable effects on hyperalgesia in both conditions.

Methods
In a randomized, controlled, double-blind trial, we assessed mechanical hyperalgesia in skin bordering the surgical wound, and an area of experimentally heat-induced secondary hyperalgesia on the thigh, in 12 patients who underwent abdominal hysterectomy within 5 days prior to the investigation. Observations were made before and during a drug challenge with remifentanil, which has been demonstrated to reduce the area of heat-induced secondary hyperalgesia in volunteers.

Results
The area of skin with surgically-induced mechanical hyperalgesia, the area of heat-induced secondary hyperalgesia, and pain during cough, were significantly reduced during remifentanil infusion compared with placebo (P = 0.008, P = 0.006, and P = 0.002, respectively). The relative reduction (% of baseline) of the area of skin with surgically-induced hyperalgesia and heat-induced secondary hyperalgesia during infusion of remifentanil was significantly associated (R2 = 0.72, P = 0.001).

Conclusions
Although remifentanil is not a highly targeted "antihyperalgesic," these results support the hypothesis that both wound hyperalgesia in postoperative patients and experimentally heat-induced secondary hyperalgesia may share common mechanisms, and that central neuronal sensitization may contribute to some aspects of postoperative pain. Antihyperalgesic drugs should be further developed and evaluated in clinical trials of postoperative pain.