bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diabetes attenuates the minimum anaesthetic concentration (MAC) and MAC‐blocking adrenergic response reducing actions of clonidine in rats
Authors: Kita T. , Kagawa K. , Mammoto T. , Takada K. , Hayashi Y. , Mashimo T. , Kishi Y. 
Published: March 2003

Background: It is well known that clonidine, an α2 agonist, reduces anaesthetic requirement and attenuates haemodynamic responses against noxious stimuli. However, the diabetic state is known to affect several functions of α2 adrenoceptors. We investigated the effects of streptozotocin (STZ)‐induced diabetes mellitus (DM) on these beneficial actions of clonidine in halothane‐anaesthetized rats.Methods: The rats were randomly assigned to one of three groups: diabetes (n=24, induced by 50 mg · kg−1 IV STZ), diabetes treated with insulin (n=24), or control (n=24). We evaluated the effects of clonidine on minimum anaesthetic concentration (MAC) and minimum concentration of halothane needed to suppress cardiovascular responses evoked by a noxious stimulus (MAC‐blocking adrenergic responses: MAC‐BAR) in each group. MAC and MAC‐BAR of halothane were determined by the tail clamp method. MAC‐BAR was defined as the MAC which attenuated haemodynamic responses within 10% following the tail clamp.Results: The diabetic state decreased MAC of halothane by approximately 10%, while MAC‐BAR of halothane had been little affected. In the diabetes group, MAC reducing action of clonidine (30 and 100 μg · kg−1, IV) was completely abolished and MAC‐BAR reducing action of clonidine was partially reduced (30 but not 100 μg · kg−1, IV). Insulin treatment preserved these actions of clonidine.Conclusion: It is suggested that the diabetic state attenuates the beneficial actions of clonidine and that insulin treatment of diabetes preserves these actions of clonidine.
Continuously infused methylene blue modulates the early cardiopulmonary response to endotoxin in awake sheep
Authors: Evgenov O. V. , Sveinbjørnsson B. , Bjertnaes L. J. 
Published: March 2003

Background: In endotoxemia and septic shock, enhanced generation of endogenous nitric oxide (NO) contributes to myocardial depression, hypotension, and derangement of gas exchange. We hypothesized that continuous infusion of methylene blue (MB), an inhibitor of the NO pathway, would counteract these effects in endotoxemic sheep.Methods: Twenty‐one sheep were anesthetized and instrumented for a chronic study with vascular catheters. On the day of the experiment, 18 conscious animals randomly received either an intravenous injection of MB 10 mg  ·  kg−1 or isotonic saline. Thirty minutes later, sheep received a 20‐min intravenous infusion of Escherichia coli endotoxin 1 μg  ·  kg−1 and either an intravenous infusion of MB 2.5 mg  ·  kg−1  ·  h−1 or isotonic saline, respectively, for 5 h. In addition, 3 animals were exposed to the same dose of MB alone.Results: MB reduced the early endotoxin‐induced declines in stroke volume, left ventricular stroke work and cardiac indices, and prevented mean arterial pressure from falling. Moreover, MB ameliorated the increases in pulmonary arterial pressure and pulmonary vascular resistance index. In addition, MB reduced the increments in venous admixture and AaPO2, decreased the falls in PaO2, SaO2, and oxygen delivery, and maintained oxygen consumption. MB also prevented the rises in body temperature and plasma nitrites and nitrates, and delayed the elevation of plasma lactate. When given alone to healthy sheep, MB transiently reduced plasma lactate and PaO2, and increased AaPO2.Conclusion: In ovine endotoxemia, continuously infused MB counteracts the early myocardial dysfunction and derangement of hemodynamics and gas exchange.
Inspiratory pressure–volume curves at different positive end‐expiratory pressure levels in patients with ALI/ARDS
Authors: Nagano O. , Tokioka H. , Ohta Y. , Goto K. , Katayama H. , Hirakawa M. 
Published: March 2003

Background: In lung protective strategy, positive end‐expiratory pressure (PEEP) slightly higher than the Pflex (the airway pressure corresponding to the lower inflection point (LIP) on the inspiratory pressure–volume (P‐V) curve measured with ZEEP) is generally recommended. However, this method to determine optimal PEEP lacks a theoretical background and there is no clinical report that investigated how the P‐V relationship would be with such PEEP. Therefore, we measured inspiratory P‐V curves at different PEEP levels to increase our knowledge about the inspiratory P‐V curve with PEEP.Methods: In eight consecutive patients with ALI/ARDS, inspiratory P‐V curves were repeatedly measured at different PEEP levels by low flow inflation technique and LIP was assessed in all inspiratory P‐V curves. Afterwards, the minimum PEEP level at which LIP was not identifiable (PEEPLIP(−)) was determined and the relationship between Pflex and PEEPLIP(−) was investigated.Results: P
flex and PEEPLIP(−) could be determined in all patients. Pflex was 9.4±2.0 cmH2O (range: 7 to 12 cmH2O) and PEEPLIP(−) was 7.9±1.6 cmH2O (range: 5 to 10 cmH2O) (mean±SD, P=0.0877). PEEPLIP(−) was lower than the Pflex in five patients, and significantly lower than the Pflex+ 2 cmH2O (P=0.0024).Conclusion: From the analysis of inspiratory P‐V curves at different PEEP levels, PEEP 2 cmH2O higher than the Pflex may not be necessary to prevent cyclic collapse and reopening of alveoli, at least in some ALI/ARDS patients. Further studies are needed to confirm this preliminary result.
Effects of intravenous anesthetics on interleukin (IL)‐6 and IL‐10 production by lipopolysaccharide‐stimulated mononuclear cells from healthy volunteers
Authors: Takaono M. , Yogosawa T. , Okawa‐Takatsuji M. , Aotsuka S. 
Published: March 2003

Background: Surgical trauma has been shown to augment the plasma concentrations of proinflammatory cytokines, which are important mediators of host defense mechanisms and the systemic inflammatory response syndrome (SIRS). Recently, it has been shown that certain kinds of surgery provoke not only a proinflammatory response (SIRS) but also a concurrent anti‐inflammatory response. The aim of this study was therefore to examine the effects of intravenous anesthetics on the synthesis of interleukin (IL)‐6 (a proinflammatory cytokine) and IL‐10 (an anti‐inflammatory cytokine) by lipopolysaccharide (LPS)‐stimulated mononuclear cells from healthy volunteers.Methods: Peripheral blood mononuclear cells (PBMCs) from 17 healthy volunteers, separated by centrifugation on a Ficoll‐Hypaque gradient, were washed and suspended in RPMI containing 10% heat‐inactivated fetal calf serum (FCS). After adding RPMI‐FCS containing various concentrations of intravenous anesthetics (propofol, thiopental, ketamine and midazolam), the PBMCs were incubated overnight in the presence of a submaximal concentration of LPS. The supernatants were collected and their IL‐6 and IL‐10 contents were assayed using enzyme‐linked immunosorbent assay kits.Results: Propofol inhibited both IL‐6 and IL‐10 production at 0.5 µg/mL, 5 µg/mL and 50 µg/mL. Conversely, thiopental induced IL‐10 production at 2 µg/mL and 20 µg/mL.Conclusion: Propofol appears to inhibit both IL‐6 and IL‐10 production by LPS‐stimulated PBMCs in vitro. Further study is required to clarify the mechanism of the suppressive effect of propofol.
EMLA® cream prior to digital nerve block for ingrown nail surgery does not reduce pain at injection of anesthetic solution
Authors: Serour F. , Ben‐Yehuda Y. , Boaz M. 
Published: March 2003

Background: Needle penetration and local anesthetic infiltration are painful steps of digital ring block. The objective of this study was to evaluate the efficacy of EMLA® cream application prior to digital ring block for surgery for ingrown big toenail.Methods: We conducted a prospective, double‐blinded, placebo‐controlled, randomized clinical trial with 81 patients (range: 12–75 years, mean ± SD: 30.3 ± 17.5 years), who underwent big toenail surgery. Prior to the digital block, EMLA cream (Group E) or a placebo cream (Group P) was applied. A visual analog scale (VAS) and a verbal rating score (VRS) from 1 to 10, 10 being most severe pain, were used for assessment of pain during the skin needle penetration and during the infiltration of the anesthetic product.Results: Data of the VAS and of the VRS during the two steps, respectively, show no significant difference in pain rating between the two groups. In Group E, the gender of the patients had a significant effect on pain perception. Male patients reported less pain than female patients, both during the needle skin penetration and during the infiltration step (P < 0.005). In Group P, reported pain did not differ by gender in either step of the procedure.Conclusions: We found no clinical benefit in using EMLA during digital nerve block. Although the digital nerves are not deeply located in the small subcutaneous space of the digit, topical anesthesia may not reach them. Moreover, swelling due to injection of the anesthetic product in this small space may also amplify the sensation of pain.
Postoperative muscle paralysis after rocuronium: less residual block when acceleromyography is used
Authors: Gätke M. R. , Viby‐Mogensen J. , Rosenstock C. , Jensen F. S. , Skovgaard L. T. 
Published: March 2003

Background: Residual muscle paralysis after anesthesia is common after pancuronium, but less common following the intermediate‐acting drugs vecuronium and atracurium. Therefore, many anesthetists do not monitor neuromuscular function when using an intermediate‐acting agent. The purpose of this prospective, randomised and double‐blind study was to establish the incidence and degree of postoperative residual block following the use of rocuronium in patients not monitored with a nerve stimulator, and to compare it with results obtained in patients monitored using acceleromyography (AMG).Methods: During propofol/opioid anesthesia, 120 adult patients were randomised to two groups, one monitored with AMG, the other using only clinical criteria without a nerve stimulator. Postoperatively, TOF‐ratio was measured with mechanomyography; a TOF‐ratio < 0.80 indicated residual muscle paralysis.Results: Residual muscle paralysis was found in 10 patients in the group without neuromuscular monitoring (16.7%) (95% confidence interval, 12–21%) and in two patients in the AMG‐monitored group (3%) (95% CI, 0–8%); (P = 0.029, Fisher's exact test). Time from end of surgery to tracheal extubation was significantly longer in the AMG‐monitored group (12.5 min) than in the group not monitored with AMG (10 min).Conclusion: Clinical evaluation of recovery of neuromuscular function does not exclude significant residual paralysis following the intermediate‐acting muscle relaxant rocuronium, but the problem of residual block can be minimized by use of AMG.
Computer‐aided ventilator resetting is feasible on the basis of a physiological profile
Authors: Uttman L , Jonson B 
Published: March 2003

Background:  Ventilator resetting is frequently needed to adjust tidal volume, pressure and gas exchange. The system comprising lungs and ventilator is so complex that a trial and error strategy is often applied. Comprehensive characterization of lung physiology is feasible by monitoring. The hypothesis that the effect of ventilator resetting could be predicted by computer simulation based on a physiological profile was tested in healthy pigs.Methods:  Flow, pressure and CO2 signals were recorded in 7 ventilated pigs. Elastic recoil pressure was measured at postinspiratory and post‐expiratory pauses. Inspiratory and expiratory resistance as a function of volume and compliance were calculated. CO2 elimination per breath was expressed as a function of tidal volume. Calculating pressure and flow moment by moment simulated the effect of ventilator action, when respiratory rate was varied between 10 and 30 min−1 and minute volume was changed so as to maintain PaCO2. Predicted values of peak airway pressure, plateau pressure, and CO2 elimination were compared to values measured after resetting.Results:  With 95% confidence, predicted pressures and CO2 elimination deviated from measured values with < 1 cm H2O and < 6%, respectively.Conclusion:  It is feasible to predict effects of ventilator resetting on the basis of a physiological profile at least in health.
Propofol infusion rate does not affect local pain on injection
Authors: Grauers A. , Liljeroth E. , Åkeson J. 
Published: March 2003

Background:  Local pain at the site of an i.v. injection of propofol is a well‐known problem, particularly in infants. This randomised investigator‐blinded crossover study was designed to assess the effect of the i.v. bolus infusion rate on propofol‐induced pain at the site of injection.Methods:  Thirty unpremedicated patients scheduled for ear‐nose‐throat or plastic surgery at Malmö University Hospital, Sweden, were given two consecutive 2.0 ml injections of propofol 10 mg/ml (Diprivan®, AstraZeneca, Sweden/UK), at different infusion rates (0.2 or 1.0 ml/s), immediately before induction of general anesthesia. Half of the patients (n=15) received the first bolus of propofol over 2 s and the second bolus over 10 s, and the other half (n=15) had their injections in reversed order. After each injection, the patient was asked by an investigator to indicate pain intensity on a visual analog scale (VAS) and to report the times of the appearance, maximum point and disappearance of pain. The injections were given approximately 2 min apart. The investigators scoring pain intensity, as indicated by the patients on a 10‐point numerical rate scale, were blinded to the order in which the injections were given, as were the patients themselves.Results:  There were no statistically significant differences in the incidence (both 86%) of intensity (median; 25th; 75th percentiles, in VAS units: 3.1; 1.0; 5.3 and 3.3; 1.4; 5.0, respectively) or duration (66±31 and 73±26 s, respectively) of pain between the faster (1.0 ml/s) and slower (0.2 ml/s) bolus infusion rates of propofol studied.Conclusions:  We conclude that the i.v. bolus infusion rate of propofol does not influence drug‐induced local pain on injection, at least not within the infusion rate interval studied. Therefore, adjusting i.v. injection speed does not seem to be a clinically useful tool for reducing the intensity or duration of propofol‐induced pain at the site of administration.
Increased synthesis of nitric oxide in rat brain cortex due to halogenated volatile anesthetics confirmed by EPR spectroscopy
Authors: Baumane L. , Dzintare M. , Zvejniece L. , Meirena D. , Lauberte L. , Sile V. , Kalvinsh I. , Sjakste N. 
Published: March 2003

Background: Halogenated volatile anesthetics (HVAs) are considered to be inhibitors of nitric oxide synthase (NOS). On other hand, NO mediates the vasodilation produced by HVAs. Thus, both increase and decrease of NO concentration in brain tissues are possible during anesthesia. Previously, we have observed an increase of NO content in rat brain cortex under halothane anesthesia. The goal of this study was to determine whether the observed phenomenon was general for this anesthetic group, if it was specific for brain cortex, and if the NO increase was due changes in NOS activity.Methods: NO scavengers were injected to adult rats 30 min prior to anesthesia. Rats were anesthetized by inhalation of an O2 mixture with volatile anesthetics (1.5% for halothane; 1% for isoflurane, 2% for sevoflurane). After 30 min of anesthesia, rats were decapitated and brain cortex, cerebellum, liver, heart, kidneys and testes were dissected, frozen in liquid nitrogen and subjected to EPR spectroscopy. Nitric oxide content was determined quantitatively based on the intensity of the NO–Fe–DETC complex spectrum and its comparison with the calibration curve.Results: In rats anesthetized with HVAs, we observed a greater than twofold increase of NO content in brain cortex as compared to the nonanesthetized animals. No significant changes were detected in other organs. The NOS inhibitor Nω‐nitro‐L‐arginine abolished the increase of NO content in brain produced by volatile anesthetics.Conclusion: The action of volatile anesthetics is coupled with an increase of NO content in the cortex dependent on NOS activity.
Serum concentration of S‐100 protein in assessment of cognitive dysfunction after general anesthesia in different types of surgery
Authors: Linstedt U. , Meyer O. , Kropp P. , Berkau A. , Tapp E. , Zenz M. 
Published: March 2003

Background:  S‐100 protein serum concentration (S‐100) serves as a marker of cerebral ischemia in cardiac surgery, head injury and stroke. In these circumstances S‐100 corresponds well with the results of neuropsychological tests. The aim of the present study was to investigate the value of S‐100 and neuron specific enolase (NSE) in reflecting postoperative cognitive deficit (POCD) after general surgical procedures.Methods:  One hundred and twenty patients undergoing vascular, trauma, urological or abdominal surgery were investigated. Serum values of S‐100 and NSE were determined preoperatively and 0.5, 4, 18 and 36 h postoperatively. Neuropsychological tests for detecting POCD were performed preoperatively and on day 1, 3, and 6 after the operation. A decline of more than 10% in neuropsychological test results was regarded as POCD. Furthermore, we retrospectively compared the S‐100 in patients with and without POCD in different types of surgery.Results: According to our definition, forty ‐eight patients had POCD (95% confidence interval: 37.5–58.5). These patients showed higher serum concentrations of S‐100 (median 024 ng/ml; range 0.01–3.3 ng/ml) compared with those without POCD (n=69; median 0.14 ng/ml; range 0–1.34 ng/ml) 30 min postoperatively (P=0.01). Neuron specific enolase was unchanged during the course of the study. Differences of S‐100 in patients with and without POCD were found in abdominal and vascular surgery but not in urological surgery.Conclusion:  When all patients are pooled, S‐100 appears to be suitable in the assessment of incidence, course and outcome of cognitive deficits. We suspect that in some surgical procedures, such as urological surgery, S‐100 appears to be of limited value in detecting POCD. Neuron specific enolase did not reflect neuropsychological dysfunction after noncardiac surgery.
Ultrasound‐guided central venous cannulation in infants and children
Authors: Åsheim P. , Mostad U. , Aadahl P. 
Published: March 2003

Background: Percutaneous central venous cannulation in infants and children is a challenging procedure. Traditionally, an external landmark technique has been used to identify puncture site. An ultrasound‐guided technique is now available and we wanted to evaluate this method in children and infants, looking specifically at the ease of use, success rate and complications.Methods: Forty‐two consecutive infants and children (median 16.5 [0–177] months and 10 [3–45] kg) scheduled for central venous catheter placement were registered. An ultrasound scanner made for guiding puncture of vessels was used. After locating the puncture site, a sterile procedure was performed using an accompanying kit to aid puncture of the vessel.Results: Cannulation was successful in all patients and we had no complications during insertion of the catheters. The right internal jugular vein was preferred in most patients, and in 95% of the patients the vein was punctured at the first attempt. The median time from start of puncture to aspiration of blood was 12 (3–180) seconds.Conclusion: The ultrasound‐guided technique for placement of central venous catheters was easy to apply in infants and children. It is our impression that it increased the precision and safety of the procedure in this group of patients.
Dynamic cerebral autoregulation in healthy adolescents
Authors: Vavilala M. S. , Newell D. W. , Junger E. , Douville C. M. , Aaslid R. , Rivara F. P. , Lam A. M. 
Published: March 2003

Background: There is little information on the limits of cerebral autoregulation and the autoregulatory capacity in children. The aim of this study was to compare dynamic cerebral autoregulation between healthy adolescents and adults.Methods: Seventeen healthy volunteers 12–17 years (n = 8) and 25–45 years (n = 9) were enrolled in this study. Bilateral mean middle cerebral artery flow velocities (Vmca; (cm/s)) were measured using transcranial Doppler ultrasonography (TCD). Mean arterial blood pressure (MAP) and end‐tidal carbon dioxide were measured continuously during dynamic cerebral autoregulation studies. Blood pressure cuffs were placed around both thighs and inflated to 30 mmHg above the systolic blood pressure for 3 min and then rapidly deflated, resulting in transient systemic hypotension.The change of Vmca to change in MAP constitutes the autoregulatory response, and the speed of this response was quantified using computer model parameter estimation. The dynamic autoregulatory index (ARI) was averaged between the two sides.Results: Adolescents had significantly lower ARI (3.9 ± 2.1 vs. 5.3 ± 0.8; P=0.05), and higher Vmca (75.2 ± 15.2 vs. 57.6 ± 15.0; P<0.001) than adults.Conclusion: The autoregulatory index is physiologically lower in normal adolescents 12–17 years of age than in adults.
Procalcitonin and neopterin as indicators of infection in critically ill patients
Authors: Ruokonen E. , Ilkka L. , Niskanen M. , Takala J. 
Published: March 2003

Background: In critically ill patients, severe infection and systemic inflammation due to non‐infectious causes produce very similar clinical presentations, and traditional infection markers do not always differentiate these two conditions. Both procalcitonin and neopterin have been suggested to aid in the early diagnosis of bacterial infections and in differentiating bacterial infections from systemic inflammatory, non‐infectious diseases or from viral infections.Methods: Procalcitonin (PCT) and neopterin were analyzed in 208 ICU patients who developed acute fever or septic shock. Blood samples were taken every 8th h within 48 h of the onset of fever or septic shock.Results: A total 162/208 of patients had infection, the most common location being the respiratory tract. Mortality was higher in infected patients (31.4% vs. 10.9%; P < 0.01). The optimum cut‐off levels in identifying patients with infection of daily peak PCT were 0.8 µg/L on day 1 and 0.9 µg/L on day 2, and both sensitivity (67.7% and 60.9%, respectively) and specificity (47.8% and 63%) were poor. Accordingly, the optimum cut‐off values of peak neopterin were 18 and 16 pg/L. The sensitivity was 62.7% on day 1 and 69.3% on day 2, while specificity was correspondingly 78.3% and 67.9%. There were no significant differences between the markers in discriminating between patients with infection or inflammation. Both PCT and neopterin increased with the severity of infection. They were higher in non‐survivors.Conclusion: PCT and neopterin were equally effective, although not very accurate in differentiating between infection and inflammation in critically ill patients. Neopterin was more specific than PCT, suggesting that neopterin is related to the activity of inflammatory response.