bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dual Effects of Intravenous Anesthetics on the Function of Norepinephrine Transporters
Authors: Hara Koji , Yanagihara Nobuyuki , Minami Kouichiro , Hirano Hideyasu , Sata Takeyoshi , Shigematsu Akio , Izumi Futoshi 
Published: November 2003

Background
Norepinephrine transporters (NETs) terminate the neuronal transmission of norepinephrine, which is released from noradrenergic neurons. To investigate the interaction with NET, the authors examined the effects of short- and long-term treatment with anesthetics on the activity and mRNA level of NET.

Methods
To assay [3H]norepinephrine uptake, bovine adrenal medullary cells in culture were incubated with [3H]norepinephrine in the presence of intravenous anesthetics, including propofol, thiamylal, and diazepam. To study the direct interaction between the anesthetics and NET, the effect of propofol on the binding of [3H]desipramine to the plasma membrane was examined. To study the long-term effect of anesthetics, [3H]norepinephrine uptake by cells pretreated with propofol for 6-24 h and [3H]desipramine binding after pretreatment for 12 h were measured. Simultaneously, we examined the effect of anesthetics on the expression of NET mRNA using the reverse transcriptase-polymerase chain reaction.

Results
All of the intravenous anesthetics inhibited [3H]norepinephrine uptake in a concentration-dependent manner. The active concentrations of propofol (1-3 microm) and thiamylal (< or = 30 microm) were similar to those encountered clinically. The kinetic analysis revealed that all the anesthetics noncompetitively inhibited [3H]norepinephrine uptake. Propofol inhibited [3H]desipramine binding with a potency similar to that observed in [3H]norepinephrine uptake. Scatchard analysis showed that propofol competitively inhibited [3H]desipramine binding. On the other hand, long-term treatment of cells with propofol (10 microm) enhanced the NET functional activity and [3H]desipramine binding, and also increased the level of NET mRNA.

Conclusions
These results suggest that intravenous anesthetics have a dual effect on NET; short-term treatment causes inhibition, whereas long-term treatment leads to up-regulation. The interaction of intravenous anesthetics with NET may modulate the neuronal transmission of norepinephrine during anesthesia.
Requirements for Muscle Relaxants during Radical Retropubic Prostatectomy
Authors: King Melinda , Sujirattanawimol Nuntiya , Danielson David R. , Hall Brian A. , Schroeder Darrell R. , Warner David O. 
Published: November 2003

Background
The need for the routine use of muscle relaxants to provide an adequate surgical field for intraabdominal surgery has not been established. This study tested the hypothesis that vecuronium decreases the frequency of unacceptable operating conditions for patients undergoing radical retropubic prostatectomy who are anesthetized with isoflurane and fentanyl.

Methods
After obtaining informed consent, patients in this blinded, placebo-controlled study were randomized to receive either an infusion of vecuronium or saline (placebo) beginning 5 min after fascial incision during the maintenance of anesthesia with at least 1 minimum alveolar concentration end-tidal isoflurane and fentanyl infusion. The surgical field was graded from 1 (excellent) to 4 (unacceptable) by the surgeons at 15-min intervals. If a grade 4 rating occurred (defined as a treatment failure), the patient received rescue vecuronium.

Results
A total of 120 patients are included in this report (59 in the vecuronium group and 61 in the placebo group). The frequency of treatment failure in the placebo group was 17 of 61 (27.9%) versus 1 of 59 (1.7%) in the control group who received vecuronium (P < 0.001). Thirty-eight patients (62.3%) in the placebo group and 52 patients (88.1%) in the vecuronium group had surgical field ratings of < or = 2 (good to excellent) at each time assessed throughout the procedure.

Conclusion
The study hypothesis was confirmed. However, an isoflurane-fentanyl anesthetic alone produced a good to excellent surgical field in approximately two thirds of patients undergoing radical retropubic prostatectomy without the use of muscle relaxants. Thus, the routine use of muscle relaxants in adequately anesthetized patients undergoing this procedure may not be indicated.
Effects of Mechanical Ventilation on Release of Cytokines into Systemic Circulation in Patients with Normal Pulmonary Function
Authors: Wrigge Hermann , Zinserling Jörg , Stüber Frank , von Spiegel Tilman , Hering Rudolf , Wetegrove Silke , Hoeft Andreas , Putensen Christian 
Published: November 2003

Background
Mechanical ventilation with high tidal volumes (V(T)) in contrast to mechanical ventilation with low V(T) has been shown to increase plasma levels of proinflammatory and antiinflammatory mediators in patients with acute lung injury. The authors hypothesized that, in patients without previous lung injury, a conventional potentially injurious ventilatory strategy with high V(T) and zero end-expiratory pressure (ZEEP) will not cause a cytokine release into systemic circulation.

Methods
A total of 39 patients with American Society of Anesthesiologists physical status I-II and without signs of systemic infection scheduled for elective surgery with general anesthesia were randomized to receive mechanical ventilation with either (1) V(T) = 15 ml/kg ideal body weight on ZEEP, (2) V(T) = 6 ml/kg ideal body weight on ZEEP, or (3) V(T) = 6 ml/kg ideal body weight on positive end-expiratory pressure of 10 cm H2O. Plasma levels of proinflammatory and antiinflammatory mediators tumor necrosis factor, interleukin (IL)-6, IL-10, and IL-1 receptor antagonist were determined before and 1 h after the initiation of mechanical ventilation.

Results
Plasma levels of all cytokines remained low in all settings. IL-6, tumor necrosis factor, and IL-1 receptor antagonist did not change significantly after 1 h of mechanical ventilation. IL-10 was below the detection limit (10 pg/ml) in 35 of 39 patients. There were no differences between groups.

Conclusions
Initiation of mechanical ventilation for 1 h in patients without previous lung injury caused no consistent changes in plasma levels of studied mediators. Mechanical ventilation with high V(T) on ZEEP did not result in higher cytokine levels compared with lung-protective ventilatory strategies. Previous lunge damage seems to be mandatory to cause an increase in plasma cytokines after 1 h of high V(T) mechanical ventilation.
Elevated Thermostatic Setpoint in Postoperative Patients
Authors: Frank Steven M. , Kluger Matthew J. , Kunkel Steven L. 
Published: November 2003

Background
The mechanism and clinical relevance of increased core temperature (Tc) after surgery are poorly understood. Because fever is used as a diagnostic sign of infection, it is important to recognize what constitutes the normal postoperative thermoregulatory response. In the current study the authors tested the hypothesis that a regulated increase in Tc setpoint occurs after surgery.

Methods
The authors prospectively studied 271 patients in the first 24 h after a variety of vascular, abdominal, and thoracic surgical procedures. Tc measured in the urinary bladder, skin-surface temperatures, thermoregulatory responses (vasoconstriction and shivering), and total leukocyte counts were assessed. In a subset of 34 patients, plasma concentrations of tumor necrosis factor, interleukin (IL)-6, and IL-8 were measured before and after surgery.

Results
In the early postoperative period, the maximum increase in Tc above the preoperative baseline averaged 1.4 +/- 0.8 degrees C (2.5 +/- 1.4 degrees F), with the Tc peak occurring 11.1 /- 5.8 h after surgery. Fifty percent of patients had a maximum Tc greater than or equal to 38.0 degrees C (100.4 degrees F) and 25% had a maximum Tc greater than or equal to 38.5 degrees C (101.3 degrees F). The progressive postoperative increase in Tc was clearly associated with cutaneous vasoconstriction and shivering, indicating a regulated elevation in Tc setpoint. The elevated Tc was associated with an increased IL-6 response but not with leukocytosis. Maximum postoperative Tc was positively correlated with duration and extent of the surgical procedure.

Conclusions
A regulated elevation in Tc setpoint (fever) occurs normally after surgery. The association between Tc elevation, extent and duration of surgery, and the cytokine response suggests that early postoperative fever is a manifestation of perioperative stress.
Rapid Hypothermic Aortic Flush Can Achieve Survival without Brain Damage after 30 Minutes Cardiac Arrest in Dogs
Authors: Behringer Wilhelm , Prueckner Stephan , Kentner Rainer , Tisherman Samuel A. , Radovsky Ann , Clark Robert , Stezoski S. William , Henchir Jeremy , Klein Edwin , Safar Peter 
Published: November 2003

Background
Neither exsanguination to pulselessness nor cardiac arrest of 30 min duration can be reversed with complete neurologic recovery using conventional resuscitation methods. Techniques that might buy time for transport, surgical hemostasis, and initiation of cardiopulmonary bypass or other resuscitation methods would be valuable. We hypothesized that an aortic flush with high-volume cold normal saline solution at the start of exsanguination cardiac arrest could rapidly preserve cerebral viability during 30 min of complete global ischemia and achieve good outcome.

Methods
Sixteen dogs weighing 20-25 kg were exsanguinated to pulselessness over 5 min, and circulatory arrest was maintained for another 30 min. They were then resuscitated using closed-chest cardiopulmonary bypass and had assisted circulation for 2 h, mild hypothermia (34 degrees C) for 12 h, controlled ventilation for 20 h, and intensive care to outcome evaluation at 72 h. Two minutes after the onset of circulatory arrest, the dogs received a flush of normal saline solution at 4 degrees C into the aorta (cephalad) via a balloon catheter. Group I (n = 6) received a flush of 25 ml/kg saline with the balloon in the thoracic aorta; group II (n = 7) received a flush of 100 ml/kg saline with the balloon in the abdominal aorta.

Results
The aortic flush decreased mean tympanic membrane temperature (Tty) in group I from 37.6 +/- 0.1 to 33.3 +/- 1.6 degrees C and in group II from 37.5 +/- 0.1 to 28.3 +/- 2.4 degrees C (P = 0.001). In group 1, four dogs achieved overall performance category (OPC) 4 (coma), and 2 dogs achieved OPC 5 (brain death). In group II, 4 dogs achieved OPC 1 (normal), and 3 dogs achieved OPC 2 (moderate disability). Median (interquartile range [IQR]) neurologic deficit scores (NDS 0-10% = normal; NDS 100% = brain death) were 69% (56-99%) in group I versus 4% (0-15%) in group II (P = 0.003). Median total brain histologic damage scores (HDS 0 = no damage; > 100 = extensive damage; 1,064 = maximal damage) were 144 (74-168) in group I versus 18 (3-36) in group II (P = 0.004); in three dogs from group II, the brain was histologically normal (HDS 0-5).

Conclusions
A single high-volume flush of cold saline (4 degrees C) into the abdominal aorta given 2 min after the onset of cardiac arrest rapidly induces moderate-to-deep cerebral hypothermia and can result in survival without functional or histologic brain damage, even after 30 min of no blood flow.
Effects of Propofol on H-reflex in Humans
Authors: Kerz Thomas , Hennes Hans-Jürgen , Fève Annaïk , Decq Philippe , Filipetti Paul , Duvaldestin Philippe 
Published: November 2003

Background
Depression of spinal cord motoneuron excitability has been proposed to contribute to surgical immobility. The H-reflex, which measures alpha-motoneuron excitability, is depressed by volatile anesthetics, whereas the action of propofol is unknown. The objective of this study was to determine the effects of propofol anesthesia on the H-reflex.

Methods
In 13 patients (group 1), H-reflex was measured before (T0), 3 min after (T1), and 10 min after (T2) a 2-mg/kg bolus dose of propofol, followed by an infusion of 10 mg x kg(-1) x h(-1). Ten patients (group 2) were studied when propofol was given via a programmable pump set to a propofol blood concentration of 6 microg/ml, and 10 patients (group 3) were studied with the pump set to 9 microg/ml. Latencies and amplitudes of H-reflexes (H0, H1, H2) and M-responses (M0, M1, M2) of the soleus muscle were recorded, and H/M ratios (H0/M0, H1/M1, H2/M2) were calculated.

Results
In group 1, H-reflex amplitudes and the H/M ratio were diminished after induction with propofol (H0 vs. H1, P = 0.033; H0/M0 vs. H1/M1, P = 0.042). After 10 min of propofol infusion, the H2/M2 ratio was still decreased versus H0/M0 (P = 0.031). In group 2, no difference was detected. In group 3, propofol depressed H-reflex amplitudes at T2 (H0 vs. H2, P < 0.01), and amplitudes were also lower at T2 than at T1 (H1 vs. H2, P < 0.01). In this group, the H/M ratio decreased from T0 to T2 (H0/M0 vs. H2/M2, P < 0.002).

Conclusions
During steady state conditions using propofol as the sole agent, a depression of the H-reflex is observed only at a high blood concentration of 9 microg/ml. The authors suggest that immobility during propofol anesthesia is not caused by a depression of spinal motoneuron circuit excitability.
Electrocardiographic Exercise Stress Testing for Cardiac Risk Assessment in Patients Undergoing Noncardiac Surgery
Authors: Gauss Albrecht , Röhm Hans-Jörg , Schäuffelen Andreas , Vogel Thomas , Mohl Ulrich , Straehle Andreas , Meierhenrich Rainer , Georgieff Michael , Steinbach Gerald , Schütz Wolfram 
Published: November 2003

Background
The value of exercise electrocardiography in the prediction of perioperative cardiac risk has yet to be defined. This study was performed to determine the predictive value of exercise electrocardiography as compared with clinical parameters and resting electrocardiography.

Methods
A total of 204 patients at intermediate risk for cardiac complications prospectively underwent exercise electrocardiography before noncardiac surgery. Of these, 185 were included in the final evaluation. All patients underwent follow-up evaluation postoperatively by Holter monitoring for 2 days, daily 12-lead electrocardiogram, and creatine kinase, creatine kinase MB, and troponin-T measurements for 5 days. Cardiac events were defined as cardiac death, myocardial infarction, minor myocardial cell injury, unstable angina pectoris, congestive heart failure, and ventricular tachyarrhythmia. Potential risk factors for an adverse event were identified by univariate and multivariate logistic regression analysis.

Results
Perioperative cardiac events were observed in 16 patients. There were 6 cases of myocardial infarction and 10 cases of myocardial cell injury. The multivariate correlates of adverse cardiac events were definite coronary artery disease (odds ratio, 8.8; 95% confidence interval [CI], 1.1--73.1; P = 0.04), major surgery (odds ratio, 4.7; 95% CI, 1.3--16.3; P = 0.02), reduced left ventricular performance (odds ratio, 2.0; 95% CI, 1.1--3.8; P = 0.03), and ST-segment depression of 0.1 mV or more in the exercise electrocardiogram (odds ratio, 5.2; 95% CI, 1.5--18.5; P = 0.01). A combination of clinical variables and exercise electrocardiography improved preoperative risk stratification.

Conclusions
This prospective study shows that a ST-segment depression of 0.1 mV or more in the exercise electrocardiogram is an independent predictor of perioperative cardiac complications.
Pharmacodynamics of Orally Administered Sustained- release Hydromorphone in Humans
Authors: Angst Martin S. , Drover David R. , Lötsch Jörn , Ramaswamy Bhamini , Naidu Sujata , Wada D. Russell , Stanski Donald R. 
Published: November 2003

Background
The disposition kinetics of hydromorphone generally necessitates oral administration every 4 h of the conventional immediate-release tablet to provide sustained pain relief. This trial examined time course and magnitude of analgesia to experimental pain after administration of sustained-release hydromorphone as compared with that after immediate-release hydromorphone or placebo.

Methods
Using a 4 x 4 Latin square double-blind design, 12 subjects were randomized to receive a single dose of 8, 16, and 32 mg sustained-release hydromorphone and placebo. The same subjects had received 8 mg immediate-release hydromorphone before this study. Using an electrical experimental pain paradigm, analgesic effects were assessed for up to 30 h after administration, and venous hydromorphone plasma concentrations were measured at corresponding times.

Results
The hydromorphone plasma concentration peaked significantly later (12.0 h [12.0--18.0] vs. 0.8 h [0.8--1.0]; median and interquartile range) but was maintained significantly longer at greater than 50% of peak concentration (22.7 +/- 8.2 h vs. 1.1 +/- 0.7 h; mean +/- SD) after sustained-release than after immediate-release hydromorphone. Similarly, sustained-release hydromorphone produced analgesic effects that peaked significantly later (9.0 h [9.0--12.0] vs. 1.5 h [1.0--2.0]) but were maintained significantly longer at greater than 50% of peak analgesic effect (13.3 +/- 6.3 h vs. 3.6 +/- 1.7 h). A statistically significant linear relation between the hydromorphone plasma concentration and the analgesic effect on painful stimuli existed.

Conclusion
A single oral dose of a new sustained-release formulation of hydromorphone provided analgesia to experimental pain beyond 24 h of its administration.
Perioperative Activation of Hemostasis in Vascular Surgery Patients
Authors: Marc Samama Charles , Thiry Dominique , Elalamy Ismael , Diaby Mohamed , Guillosson Jean-Jacques , Kieffer Edouard , Coriat Pierre 
Published: November 2003

Background
Perioperative activation of hemostasis could play an important role in the occurrence of postoperative cardiac events. The authors conducted a prospective study to assess platelet function, coagulation, and fibrinolysis status during and after infrarenal aortic surgery.

Methods
Seventeen patients were studied. Excluded were patients with preoperative coagulopathies or liver disease, or cardiac or renal insufficiency; patients receiving anticoagulant treatment, antiplatelet agents, nonsteroidal antiinflammatory agents, fresh frozen plasma, or platelet concentrates; and patients undergoing reoperation and septic patients. Blood samples were drawn before induction (T1), 1 h after incision (T2), 1 h after extubation (T3), 24 h postoperatively (T4), 48 h postoperatively (T5), and at day 7 (T6). The following tests were performed: platelet count, platelet aggregation, platelet flow cytometry for CD62 and CD63, usual coagulation tests, thrombin--antithrombin complexes, plasminogen activator inhibitor 1.

Results
A significant increase of adenosine diphosphate--induced platelet aggregation was observed postoperatively at T4 and T5. This was not associated with a change of flow cytometry profile. No increase of thrombin--antithrombin complex levels was observed. A higher fibrinogen rate was detected at T5 and T6. Greater amounts of plasminogen activator inhibitor 1 were detected at T3 and T4. Thus, thrombin generation was limited and fibrinolysis was impaired postoperatively. Platelets were not activated in the postoperative period, as shown by flow cytometry, but were prone to be activated, as shown by aggregation studies.

Conclusion
The association of more easily activated platelets with a higher fibrinogen rate and a temporary shut down of fibrinolysis during the early postoperative period may indicate an increased thrombotic risk in patients undergoing major vascular surgery.
The Combitube in Elective Surgery
Authors: Gaitini Luis A. , Vaida Sonia J. , Mostafa Somri , Yanovski Boris , Croitoru Milian , Capdevila Marisa D. , Sabo Edmond , Ben-David Bruce , Benumof Jonathan 
Published: November 2003

Background
The Combitube has proved to be a valuable device for securing the airway in cases of difficult intubation. This study investigated the effectiveness of the Combitube in elective surgery during both mechanical and spontaneous ventilation.

Methods
Two hundred patients classified as American Society of Anesthesiologists physical status I and II, with normal airways, scheduled for elective surgery were randomly allocated into two groups: nonparalyzed, spontaneously breathing (n = 100); or paralyzed, mechanically ventilated (n = 100). After induction of general anesthesia and insertion of the Combitube, oxygen saturation, end-tidal carbon dioxide and isoflurane concentration, systolic and diastolic blood pressure and heart rate, as well as breath-by-breath spirometry data were obtained every 5 min.

Results
In 97% of patients, it was possible to maintain oxygenation, ventilation, and respiratory mechanics, as well as hemodynamic stability during either mechanical or spontaneous ventilation for the entire duration of surgery. The duration of surgery was between 15 and 155 min.

Conclusions
The results of this study suggest that the Combitube is an effective and safe airway device for continued management of the airway in 97% of elective surgery cases.
Study of the “Sniffing Position” by Magnetic Resonance Imaging
Authors: Adnet Frédéric , Borron Stephen W. , Dumas Jean Luc , Lapostolle Frédéric , Cupa Michel , Lapandry Claude 
Published: November 2003

Background
The "sniffing position" is widely considered essential to the performance of orotracheal intubation and has become the cornerstone of training in anesthesiology. However, the anatomic superiority of this patient head position has not been established.

Methods
Eight healthy young adult volunteers underwent magnetic resonance imaging scanning in three anatomic positions: head in neutral position, in simple extension, and in the "sniffing position" (neck flexed and head extended by means of a pillow). The following measurements were made on each scan: (1) the axis of the mouth (MA); (2) the pharyngeal axis (PA); (3) the laryngeal axis (LA); and (4) the line of vision. The various angles between these axes were defined: alpha angle between the MA and PA, beta angle between PA and LA, and delta angle between line of vision and LA.

Results
Both simple extension and sniffing positions significantly improved (P < 0.05) the delta angle associated with best laryngoscopic view. Our results show that the beta value increases significantly (P < 0.05) when the head position is shifted from the neutral position (beta = 7 +/- 6 degrees ) to the sniffing position (beta = 13 +/- 6 degrees ), and the alpha value slightly (but significantly) decreases (from 87 +/- 10 degrees to 63 +/- 11 degrees; P < 0.05). Anatomic alignment of the LA, PA, and MA axes is impossible to achieve in any of the three positions tested. There were no significant differences between angles observed in simple extension and sniffing positions.

Conclusions
The sniffing position does not achieve alignment of the three important axes (MA, PA, and LA) in awake patients with normal airway anatomy.