bluuebunny/crossref_metadata_2025_split huggingface dataset:
Emergence from isoflurane/N2O or isoflurane anaesthesia
Authors: EINARSSON S. , BENGTSSON A. , STENQVIST O. , BENGTSON J. P. 
Published: January 2009

Background: The first goal of anaesthetic recovery is return of the patient's ability to independently maintain respiratory and circulatory functions. Nitrous oxide remains popular due to minor effects on the cardiovascular and respiratory systems. However, diffusion hypoxaemia can occur during recovery and there is a potential advantage of providing the patient with only a potent vaporised agent.Results:Patients anaesthetised with isoflurane/N2O resumed their spontaneous breathing 16 min earlier and were extubated 22 min earlier than those anaesthetised with only isoflurane. At extubation, total MAC and end–tidal CO2 were similar in both groups, 0.22–0.26 and 5.5–5.9 vol%, respectively. The isoflurane/N2O group had greater minute ventilation and CO2 excretion rates than the isoflurane group throughout the emergence period. There were no significant differences between the groups in blood gas variables or in heart rate, mean arterial blood pressure or cardiac index. Cardiac index was between 3.4 and 3.9 1 m‐2 min‐1 throughout the emergence period in both groups.Conclusion:Patients anaesthetised with only isoflurane had a longer delay until resumption of spontaneous breathing and extubation in the emergence period. Minute ventilation and carbon dioxide elimination were also significantly more suppressed throughout emergence after anaesthesia with isoflurane as compared with isoflurane/N2O.Methods: This randomised study of 20 gynaecological patients evaluated respiratory and circulatory variables during emergence after anaesthesia with equipotent mixtures of isoflurane/ nitrous oxide or isoflurane. Inspired, end–tidal and mixed expired gas concentrations, expired minute volume, pulse oximetry saturation and arterial blood gases were registered. Monitoring of cardiac output was performed by transthoracic bioimpedance.
Influence of anaesthesia and muscle relaxation on intubating conditions and sympathoadrenal response to tracheal intubation
Authors: SPARR H. J. , LEO C. , LADNER E. , DEUSCH E. , BAUMGARTNER H. 
Published: January 2009

Background: The study aimed to assess the relative influence of anaesthesia and muscle relaxation on intubating conditions and the haemodynamic and catecholamine responses to tracheal intubation.Methods: Sixty ASA 1 or 2 patients were randomly assigned to one of four groups (15 patients each) that differed in the depth of anaesthesia (thiopentone plus fentanyl 2.5 μg kg‐1 or thiopentone alone) and the degree of vecuronium–induced neuromuscular block (100% or _>: 65%) at intubation. Muscle relaxation was measured at 0.1 Hz by means of mechanomyography. Heart rate (HR) and mean arterial blood pressure (MAP) were measured before and after induction of anaesthesia, and 1 min and 5 min following intubation, while adrenaline (A) and noradrenaline concentrations (NA) were determined from arterial blood samples.Results: Intubating conditions were improved primarily by providing complete muscle relaxation at the adductor pollicis muscle (P<0.001) and to a lesser extent by adding fentanyl to thiopentone (P=0.04). The response of HR and MAP to tracheal intubation was attenuated mainly by fentanyl (P<0.001). Complete muscle relaxation further diminished the response of MAP to intubation (P=0.03). Changes in A and NA were dependent on the depth of anaesthesia only (P =>0.01).Conclusion: The results of the study demonstrate that the sympathoadrenal response to intubation is attenuated by adding fentanyl (2.5 kg‐1) to an induction regimen with thiopentone, whereas provision of complete muscle relaxation at the adductor pollicis muscle is necessary to attain smooth intubating conditions.
Atracurium–induced neuromuscular block is not affected by chronic anticonvulsant therapy with carbamazepine
Authors: SPACER A. , NEIGER F. X. , SPISS C. K. , KRESS H. G. 
Published: January 2009

Background: Patients on chronic anticonvulsant therapy are relatively resistant to some nondepolarizing neuromuscular blockers. Because of the controversial reports on atracurium, the purpose of the present study was to determine the effect of longterm carbamazepine treatment on the neuromuscular block produced by this muscle relaxant.Methods: Eighteen otherwise healthy individuals scheduled for neurosurgical interventions were studied. Eight patients had received carbamazepine for an average of 41 weeks (range 4–156 weeks) prior to surgery. Ten patients without carbamazepine exposure served as controls. After premedication with oral diazepam, anaesthesia was induced with fentanyl and thiopental and maintained with nitrous oxide and isoflurane in oxygen. Atracurium was given for neuromuscular blockade and the evoked electromyogram (EMG) was recorded with a Datex Monitor NMT.Results: The lag time, the onset time, the duration 10%, 25%, 50%, 75% and the interval 25–75% did not differ between the groups.Conclusion: Our results with atracurium differ from previous data demonstrating an influence of carbamazepine therapy on the pharmacokinetics and/or pharmacodynamics of other nondepolarizing muscle relaxants. As documented in this study, atracurium produces adequate neuromuscular block in patients chronically exposed to carbamazepine. Chronic carbamazepine therapy does not influence the onset time and duration of action of atracurium–induced neuromuscular block.
Attenuation of serotonin–induced contractures in skeletal muscle from malignant hyperthermia–susceptible patients with dantrolene
Authors: WAPPLER F. , SCHOLZ J. , RlCHTHOFEN V. VON , FlEGE M. , KÖCHLING A. , LAMBRECHT W. , ESCH J. SCHULTE AM 
Published: January 2009

Background: Porcine malignant hyperthermia (MH) can be triggered by administration of certain serotonin2receptor agonists. Pretreatment with dantrolene completely abolished serotonininduced MH. The purpose of this study was to investigate the effects of the serotonin2receptor agonist l–(2,5–dimethoxy–4–iodophenyl)–2–aminopropane (DOI) in skeletal muscle specimens from MH–susceptible (MHS) and MH–nonsusceptible (MHN) patients following pretreatment with dantrolene.Results: Administration of DOI 0.02 mM induced contractures in muscle specimens from MHS and MHN patients. Contracture development started significantly earlier in MHS than in MHN specimens. In MHS muscle the maximum contracture was significantly greater than in MHN. Pretreatment with dantrolene significantly delayed the start of contracture development in MHS muscles, whereas in MHN muscles no contractures were observed after dantrolene. The contracture maximum was significantly reduced in MHS.Conclusion: The acceleration of DOI–induced contracture development in skeletal muscle specimens from MHS patients indicates that an altered serotonin system might be involved in human MH. Dantrolene effectively delayed serotonin–induced contractures. Further investigations are needed to determine whether serotonin2receptors of skeletal muscle from MHS subjects are altered in function or structure, or whether this response is a secondary phenomenon.Method: We used muscle specimens surplus to diagnostic requirements from 12 MHS and 13 MHN patients in this study. In the first experiment, DOI 0.02 mM was added to the organ bath. In the second experiment, muscle specimens were preincubated with dantrolene 0.5 μM or 1.0 nM, respectively, for 10 min before DOI 0.02 mM was administered.
Effects of cisatracurium on cerebral and cardiovascular hemodynamics in patients with severe brain injury
Authors: SCHRAMM W. M. , JESENKO R. , BARTUNEK A. , GILLY H. 
Published: January 2009

Background: For neuroanesthesia and neurocritical care the use of drugs that do not increase or preferentially decrease intracranial pressure (ICP) or change cerebral perfusion pressure (CPP) and cerebral blood flow (CBF) are preferred. The current study investigates the effects of a single rapid bolus dose of cisatracurium on cerebral blood flow velocity, ICP, CPP, mean arterial pressure (MAP) and heart rate (HR) in 24 mechanically ventilated patients with intracranial hypertension after severe brain trauma (Glasgow coma scale 6) under continuous sedation with sufentanil and midazolam.Methods: Patients were randomly assigned to receive either 2XED95 (n=12) or 4XED95 (n=12) of cisatracurium as a rapid i.v. bolus injection. Before and after bolus administration mean cerebral blood flow velocity (BFV, cm/s) was measured in the middle cerebral artery using a 2–MHz transcranial Doppler sonography system, ICP (mm Hg) was measured using an extradural probe, and MAP (mm Hg) and HR (b/min) were measured during a study period of 20 min. Cerebral perfusion pressure (CPP=MAP–ICP) was also calculated.Results: Our data show that a single bolus dose of up to 4 × ED95 cisatracurium caused no significant (P<0.05) changes in BFV, ICP, CPP, MAP and HR. Possible histamine‐related events were not observed during the study.Conclusions: The results from this study suggest that cisatracurium is a safe neuromuscular blocking agent for use in adult severe brain–injured patients with increased ICP under mild hyperventilation and continuous sedation.
Preoperative metoprolol improves cardiovascular stability and reduces oxygen consumption after thoracotomy
Authors: JAKOBSEN C.–J. , BILLE S. , AHLBURG P. , RYBRO L. , PEDERSEN K. D. , RASMUSSEN B. 
Published: January 2009

Background: Increased sympathetic activity perioperatively and associated cardiovascular effects play a central role in cardiovascular complications. High thoracic epidural blockade attenuates the sympathetic response, but even with complete pain relief, haemodynamic and endocrine responses are still present. Beta–adrenoceptor blockade is effective in situations with increased sympathetic activity. This study was designed to evaluate the perioperative haemodynamic effect of preoperative βblockade and its influence on the haemodynamic aspects of the surgical stress response.Methods: Thirty–six otherwise healthy patients undergoing elective thoracotomy for lung resection were randomised doubleblinded to receive either 100 mg metoprolol or placebo preoperatively. Anaesthesia was combined high thoracic epidural block and general anaesthesia. The epidural analgesia was continued during recovery. Patients were monitored with ECG, pulse oximetry, invasive haemodynamic monitoring, arterial blood gases and electrolytes.Results: After induction of anaesthesia the mean arterial pressure (MAP) decreased in both groups, and decreased further in the placebo group after initiation of the epidural block. The heart rate (HR) was slightly less throughout the observation period after metoprolol. Peroperatively, the only difference in measured haemodynamics was a marginally higher MAP after metoprolol. Postoperative cardiac index (CI) was lower with a lower variability and cardiac filling pressures were slightly higher in the metoprolol group. The oxygen consumption index was higher after placebo throughout the observation period, with no difference in the oxygen delivery.Conclusion. We found that preoperative β–blockade during combined general anaesthesia and high thoracic epidural blockade stabilised perioperative HR and CI and decreased total oxygen consumption.
The effect of succinylcholine on atracurium–induced neuromuscular block
Authors: ROED J. , LARSEN P. B. , OLSEN J. S. , ENGBÆK J. 
Published: January 2009

Background: The interaction between prior succinylcholine and atracurium has been found only after full recovery of succinylcholine block. We investigated whether the effect of succinylcholine on atracurium block may depend on the level of recovery from succinylcholine.Methods: Fifty patients in 4 groups received atracurium 0.2 mg/ kg when first response (Tl) in train–of–four (TOF) after succinylcholine 1 mg/kg had recovered to 5%, 25%, 75% or 100%. A control group received only atracurium. The following indices were compared: the time from injection of atracurium to maximum block (onset time) and to return of Tl to 25% (duration 25%), maximal depression of Tl, time from 25% to 75% recovery of Tl (interval 25–75%) and time from injection of atracurium to a TOF ratio of 0.75 (duration TOF 0.75).Results: Onset time was shorter, max Tl depression was greater and duration 25% increased the more succinylcholine recovery progressed. Neither interval 25–75% nor duration TOF 0.75 varied with the level of recovery from succinylcholine. The control group showed a shorter latency and onset time compared to the early (5%) recovery group and a longer onset time and less depressed Tl compared to the late (100%) recovery group. There was no difference between the control group and the early or late recovery groups, respectively for duration 25% or duration TOF 0.75.Conclusion: The effect of prior administration of succinylcholine on atracurium block depends on the state of recovery from succinylcholine and concerns both its potency, onset and duration characteristics.
Effects of isoflurane on in vivo release of acetylcholine in the rat cerebral cortex and striatum
Authors: SHICHINO T. , MURAKAWA M. , ADACHI T. , NAKAO S. , SHINOMURA T. , KURATA J. , MORI K. 
Published: January 2009

Background: Acetylcholine (ACh) is one of the major excitatory neurotransmitters in the central nervous system, and changes in neural activity induced by anesthesia alter the release of ACh. However, the effects of isoflurane, one of the most widely used volatile anesthetics, on ACh release are not known. The present study attempts to clarify the dose–effect relationship of isoflurane on the in vivo release of ACh in rat brains.Methods: Changes in the extracellular concentration of ACh and choline in the cerebral cortex and striatum induced by 0.5, 1.0, and 1.5 minimum alveolar concentration (MAC) of isoflurane were determined using a brain microdialysis technique.Results: In the cortex, the ACh release decreased to 30.8±10.1 (mean±SEM), 10.2±4.1, and 8.1±2.9% of basal value by increasing doses of isoflurane, and in the striatum, to 73.3±4.4, 49.2±4.2, and 40.7±4.5%. The ACh release rapidly recovered control levels with the discontinuance of isoflurane. Choline concentration was not changed significantly by isoflurane except for a decrease to 74.8±4.6% in the striatum by 0.5 MAC. In both the cortex and striatum, the choline concentration decreased with the discontinuance of isoflurane to 70.3±13.3, and 68.2±5.4%, respectively.Conclusion: The fact that all classic anesthetics reported previously, as well as isoflurane, reduce ACh release supports the hypothesis that the suppression of cholinergic cells is, at least in part, one of the mechanisms of anesthesia.
The duration of action of bupivacaine, levobupivacaine, ropivacaine and pethidine in peripheral nerve block in the rat
Authors: DYHRE H. , LÅNG M. , WALLIN R. , RENCK H. 
Published: January 2009

Background: There is a current interest in local anaesthetic drugs/formulations exhibiting long durations of sensory block and minor motor–blocking effects.Objectives: To compare the duration of sensory and motor blockade in peripheral nerve blocks induced by the new agents ropivacaine and levobupivacaine, with that of racemic bupivacaine and pethidine.Methods: Groups of 8 male Sprague–Dawley rats were subjected to infraorbital (IONB) or sciatic nerve block (SNB) employing 0.2 ml of differently concentrated solutions of bupivacaine, levobupivacaine, ropivacaine or pethidine. The sensory blocking effect in IONB is expressed as (i) the time to elicitation of an abdominal jerk by electrical stimulation at arbitrarily chosen (threshold) intensities (IONB degree 3, 5, 8 and 10), and as (ii) the area under the curve (AUC, threshold intensities vs time). The duration of motor block in SNB is given as the time from injection to regained ability to walk and grip normally with the toes. Comparisons of the dose–effect relationships for the investigated agents were made by analysis of covariance.Results: In IONB the log (dose)–log (effect) lines for bupivacaine, levobupivacaine and ropivacaine did not deviate from parallelism. The duration of sensory block induced by equimolar doses of these agents was similar, although bupivacaine exerted more pronounced effects than levobupivacaine (AUC by 25%, P=0.001; IONB degree 3 by 14%, P=0.03). In SNB only the log (dose)–log (duration) lines for bupivacaine vs levobupivacaine were found not to deviate from parallelism, both agents exerting similar durations of action. The motor–blocking effects of ropivacaine showed an inverse dose–duration relationship (P=0.019).Conclusions: Equimolar doses of the investigated local anaesthetics exerted similar durations of sensory blockade in a peripheral nerve block model in the rat.
Comparison of the effect of intravenous ketoprofen, ketorolac and diclofenac on platelet function in volunteers
Authors: NIEMI T. T. , TAXELL C. , ROSENBERG P. H. 
Published: January 2009

Background: Nonsteroidal anti–inflammatory drugs (NSAIDs) inhibit prostaglandin synthesis which may result in impaired platelet function. Because NSAIDs have different abilities to inhibit cyclo–oxygenases we compared the effect of intravenous ketoprofen, ketorolac and diclofenac on platelet function in volunteers.Methods: Ten healthy male volunteers were given ketoprofen 1.4 mg kg‐1, ketorolac 0.4 mg kg‐1 and diclofenac 1.1 mg kg‐1 in saline i.v. on three different occasions, at more than one–week intervals, in a randomized double–blind crossover study. Platelet function was evaluated before (sample 0), 2 (sample 2) and 24 h (sample 3) after the beginning of the infusion.Results: Two of the volunteers had no secondary platelet aggregation in their aggregation curves before the experiment (sample 0, studied three times) and their results were excluded from the final analysis. Diclofenac inhibited adrenaline (0.9 μg–ml‐1) induced platelet aggregation less (median maximal aggregation 22.5%) than ketoprofen (18.3%) and ketorolac (15.7%) (P<0.05) in sample 2. In the ketorolac group in sample 3 an impairment of adrenaline (0.9 ng ml‐1) induced platelet aggregation was still seen (26.7%) (P<0.05) but not in the other groups. Diclofenac did not affect adenosine diphosphate (ADP) induced platelet aggregation. However, ketorolac caused an impairment in ADP (3 μM and 6 μM) induced platelet aggregation and ketoprofen in ADP (6 μM) induced platelet aggregation in sample 2. Bleeding time was prolonged (P<0.05) after ketoprofen and ketorolac (sample 2) but not after diclofenac. Platelet retention on glass beads was unaffected by the tested drugs.Conclusion: Ketoprofen, ketorolac and diclofenac caused a reversible platelet dysfunction. Diclofenac had the mildest effect, while platelet dysfunction was still seen 24 h after the beginning of ketorolac.
Deep accidental hypothermia and cardiac arrest rewarming with forced air
Authors: KOLLER R. , SCHNIDER T. W. , NEIDHART P. 
Published: January 2009

Background: During the last two cold winters we have treated 5 severely hypothermic patients (temperature below 30C) with active external rewarming rather than with extracorporal circulation and heat exchanger.Patients: Two patients were found in cardiac arrest, and 3 victims of mountain accidents suffered deep hypothermia without arrest. In one of them, ventricular fibrillation (VF) was converted successfully to a sinus rhythm at a core temperature of 25.9C. Both arrested patients developed an adequate hemodynamic state during resuscitation although they were at very low temperature. All the patients were warmed with a convective cover inflated with warm air of about 38A°C (Bair Hugger). The core temperature increased by approximately 1°C/h in all patients. During rewarming we observed neither an initial drop of the core temperature (afterdrop) nor cardiac arrhythmias. The outcome of all 5 patients was good without neurological sequelae.Conclusion: We conclude that external rewarming with forced air is a feasible alternative to cardiopulmonary bypass in severely hypothermic patients with electrical activity. This method can be used even in patients with VF because defibrillation can be successfully performed in deep hypothermia. Although afterdrop during external rewarming is feared, we did not observe this phenomenon. Rewarming with forced air is inexpensive, easy to perform and direct access to the patient is possible at any time. It does not require heparinisation and can be used in hospitals where they do not have cardiopulmonary bypass facilities. Thus, this method is particularly useful in situations when the hypothermic patient cannot be transferred to a major medical center.
Intra‐arterial regional anaesthesia for hand surgery: a dose‐finding study
Authors: KOSCIELNIAK‐NIELSEN Z. J. , HESSELBJERG L. 
Published: January 2009

Background: Intra‐arterial regional anaesthesia (IARA) may be useful for ambulatory hand surgery in patients with poor veins. This randomized, double‐blind study assessed which of the three doses of lignocaine gives the optimal analgesia with a minimum of adverse effects.Methods: A preservative‐free, alkalinized 0.5% lignocaine 1, 2 or 2.89 mg/kg body weight was injected into the radial arteries of 60 adult patients, allocated to three equal groups, to produce anaesthesia for carpal tunnel releases, capsulotomies, tenosynovectomies, palmar fasciectomies, Z‐plastics, arthro‐plastics, arthrodeses etc.Results: Surgical analgesia and motor block were best in group 3 (P < 0.01), whereas injection and tourniquet pain scores were similar in the three groups. Onset of analgesia was similar in all groups, and varied between 2 and 15 min. Can‐nulation time, surgery start time and tourniquet time were also similar in all groups, as were operating conditions and patient's acceptance of the method. No significant cardiovascular changes were observed after tourniquet release in any of the groups. Plasma lignocaine concentrations were lowest in group 1 (1 mg/kg) (P < 0.001). Five patients in group 1, seven in group 2 and seventeen in group 3 developed small bruises at the cannulation site (P <0.001). Six patients (two in group 1, three in group 2 and one in group 3) had minor symptoms of lignocaine toxicity after tourniquet release (NS). No other complications were observed.Conclusions: The highest dose of lignocaine produces best surgical analgesia, without increasing the risk of toxicity. However, many patients receiving this dose will develop bruises at the injection site, and an occasional patient may need supplemental analgesia.
The effects of simulated Bier block IVRA on intracompartmental tissue pressure
Authors: MABEE J. R. , SHEAN C. , ORLINSKY M. , ANDROY L. , CARTER V. 
Published: January 2009

Background:Intravenous regional anesthesia (IVRA) is a useful anesthetic method for closed reduction of fractures. However, IVRA has been associated with an increased incidence of compartment syndrome when treating tibial shaft fractures. The purpose of this study was to measure changes in anterior leg compartment pressures during simulated IVRA.Methods:A volunteer study was performed. An indwelling catheter placed in a consistent location between subjects was used to measure tissue pressure. A vinyl leg splint was used for exsanguination followed by thigh tourniquet inflation (300 mmHg). Normal saline (1.5 mL/kg) was injected through the greater saphenous vein (1.0 mL/s). Pressure measurements were obtained before and after tourniquet inflation, at 10 mL increments during saline injection, and intermittently after volume injection with the tourniquet inflated, then deflated.Results:There was no significant difference in tissue pressure before (2.4±2.2 mmHg) and after (4.3±3.7 mmHg) tourniquet inflation (P = 0.11). No significant differences in tissue pressure were found as a function of injected volume (P = 0.62), as a function of time following saline injection during tourniquet inflation (P = 0.08), and after tourniquet deflation (P = 0.16).Conclusions:We conclude that in the normal atraumatic limb, simulated IVRA using normal saline does not increase tissue pressure within the anterior leg compartment.