bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sequestration of vecuronium bromide during extremity surgery involving use of a pneumatic tourniquet
Authors: BARNETTE R. E. , ERIKSSON L. I. , COONEY G. F. , BRISTER N. W. , JOHANSON N. , CARLSSON C. , SHARMA M. L. 
Published: January 2009

Background: We hypothesized that sequestration of a neuromuscular blocking agent could occur during surgery involving use of an extremity tourniquet and cause changes in neuromuscular function after tourniquet release.Methods: Sixteen patients scheduled for total knee replacement were randomized to one of two groups. In Group 1,10 patients were administered O.lmg/kg of vecuronium 5 minutes prior to inflation of a pneumatic tourniquet; in Group II, 6 patients were administered O.lmg/kg of vecuronium after inflation of the tourniquet. The twitch (T1) and train‐of‐four (TOF) were analyzed before and after release of the tourniquet, as was the rate of recovery of T1 and TOF. Serial vecuronium plasma levels were drawn during the study.Results: The T1 and TOF responses and the T1 and TOF recovery rates were not significantly different between groups at tourniquet deflation. In Group I, after release of the tourniquet, Tj and TOF recovery rate decreased significantly over a 10‐min period (10%±3 to 4%±4 and 0.12±0.06 to 0.06±0.04, mean±SD, respectively); in Group II, T1 and TOF recovery rate increased significantly over a 10‐min period following deflation of the tourniquet (10%±6 to 14%±7 and 0.10±0.03 to 0.18±0.02, respectively). Changes in pharmacodynamics were temporally associated with transient but statistically significant changes in vecuronium plasma levels. Overall pharmacokinetics during the study period were comparable between groups. After administration of neostigmine 30–40 μg/ kg i.v. all subjects in both groups showed complete TOF recovery within 15 min.Conclusions: Sequestration of a bolus dose of vecuronium, by a pneumatic tourniquet, causes transient changes in pharmacokinetics and pharmacodynamics. These changes are of limited clinical importance and do not affect reversibility of neuromuscular block.
Hyperosmotic‐hyperoncotic solutions during abdominal aortic aneurysm (AAA) resection
Authors: CHRIST F. , NIKLAS M. , KREIMEIER U. , LAUTERJUNG L. , PETER K. , MESSMER K. 
Published: January 2009

A largely positive perioperative fluid balance during both elective and emergency abdominal aortic aneurysm repair (AAA) may put patients at risk of developing left ventricular failure and may thus contribute to morbidity. In the present paper we report on a prospective study using hyperosmotic‐hyperoncotic solutions (HHS) infused during clamping of the aorta, for the prevention of declamping shock, and the associated reduction in perioperative fluid requirements. The major aim of this paper was to determine the efficacy of an HHS infusion when given over 20 minutes and to detect possible adverse effects of HHS.For perioperative fluid replacement 12 patients received crystalloid solutions with HHS [250 ml of 7.2% NaCl combined with either 6% Dextran (n=3), 6% Hydroxyethylstarch (HES, n=4) or 10% HES (n=5)]. In 16 controls, crystalloids with 1000 ml of HES 10% were infused. Patients were invasively monitored and hemodynamic parameters frequently assessed during the operation, which were statistically analyzed in relation to the start of the fluid loading during clamping of the aorta. One patient showed an anaphylactoid reaction to HES, otherwise no side effects of HHS were observed during infusion (no hypotension, no pathological EKG changes). Plasma sodium and chloride concentration as well as osmolality rose resulting in an osmotic gradient and a desired intravascular volume expansion. Prior to declamping pulmonary capillary wedge pressure had increased to the desired value of > 13 mmHg and <18 mmHg. Oxygen delivery was significantly elevated upon HHS and remained so post declamping, whereas no change was observed in controls. During clamping systemic vascular resistance was significantly decreased, but was unchanged in controls. The perioperative fluid balance of patients receiving HHS was 2471.0±948.6 ml, which was significantly less than +3386.7±1247.9 ml of controls (P < 0.01).We suggest that HHS opens new perspectives in perioperative fluid management of both elective and emergency AAA repair, since hemodynamic parameters are improved and the overall fluid balance is less positive, thus decreasing the likelihood of edema formation. Moreover, the previously described positive microcirculatory effects of HHS may be particular beneficial in some high‐risk patients.
Morphine metabolites
Authors: CHRISTRUP L. L. 
Published: January 2009

Morphine is a potent opioid analgesic widely used for the treatment of acute pain and for long‐term treatment of severe pain. Morphine is a member of the morphinan‐framed alkaloids, which are present in the poppy plant. The drug is soluble in water, but its solubility in lipids is poor.In man, morphine‐3‐glucuronide (M3G) and morphine‐6‐glucu‐ronide (M6G) are the major metabolites of morphine. The metabolism of morphine occurs not only in the liver, but may also take place in the brain and the kidneys. The glucuronides are mainly eliminated via bile and urine. Glucuronides as a rule are considered as highly polar metabolites unable to cross the blood‐brain barrier. Although morphine glucuronidation has been demonstrated in human brain tissue, the capacity is very low compared to that of the liver, indicating that the M3G and M6G concentrations observed in the cerebrospinal fluid (CSF) after systemic administration reflect hepatic metabolism of morphine and that the morphine glucuronides, despite their high polarity, can penetrate into the brain. Like morphine, M6G has been shown to be relatively more selective for μ‐receptors than for 5‐ and K‐receptors while M3G does not appear to compete for opioid receptor binding.The analgesic properties of M6G were recognised in the early 1970s and more recent work suggests that M6G might significantly contribute to the opioid analgesia after administration of morphine. The analgesic potency of M6G after intracerebroven‐tricular (ICV) or intrathecal (IT) administration in rats is from 45–800 timer greater than that of morphine, depending on the animal species and the experimental antinociceptive test used. Furthermore, the development of a sensitive high‐performance liquid chromatography (HPLC) assay for the quantitative determination of morphine, M6G and M3G has revealed that M6G and M3G were present in abundance after chronic oral morphine administration and that the area under the plasma concentration‐time curve exceeded that of morphine. M3G has been found to antagonise morphine and M6G induced analgesia and ventilatory depression in the rat, which has led to the hypothesis that M3G may influence the development of morphine tolerance. M3G exhibits no analgesic effect after ICV or IT administration. Some studies do, however, indicate that M3G may cause non‐opioid mediated hyperalgesia/allodynia and convulsions after IT administration in rats. These observations led to the hypothesis that M3G might be responsible for side‐effects, hyperalgesia/allodynia and myoclonus seen after high‐dose morphine treatment.
Opioids in the brain: supraspinal mechanisms in pain control
Authors: JENSEN T. S. 
Published: January 2009

Systemically administered opioids produce a profound inhibition of noxious‐evoked activity peripherally, spinally and supraspinally in several species, including man. The role of the brain in opioid mediated‐pain control has been less well characterized than that occurring at lower levels in the nervous system. Yet, classical studies indicate that in morphine‐induced analgesia the individual senses noxious stimuli, but the affective, motivational and aversive character of the stimulus is no longer present. This observation indicates that morphine probably exerts a specific action on those brain systems that control complex behaviors like aversion and motivation. The failure to document such effects in experimental studies may in part be explained by less suitable methods for assessing antinocicep‐tion, e.g. measurements of simple reflex behaviors. Experimental animal studies show that supraspinal opioids may influence nociception by several distinct mechanisms, which differ from those seen in the spinal cord: Change of activity in descending bulbospinal pathways. Direct inhibition of noxious throughput at brainstem level. Indirect inhibition of noxious responding brainstem neurons projecting to supraspinal centers. Influence ascending forebrain systems. Direct cortical or thalamic inhibition.In humans, the antinociceptive actions of opioids occurring in the brain has until recently been like looking into a “black box”. The introduction of new imaging techniques may provide new tools for directly measuring the antinociceptive action of opioids in the brain under normal and pathological conditions. In particular, the emotional‐affective aspect of pain and how this is modulated by opioids will be of interest to study.
Psychomotor and cognitive functioning in cancer patients
Authors: SJOGREN P. 
Published: January 2009

Psychomotor and cognitive dysfunction in cancer patients can be classified into two main categories according to etiology: disease‐induced factors (metabolic disturbances, brain metastasis, pain, etc.) and treatment‐related factors (drugs, antineoplastic therapy, etc.). In particular, the effects of chronic opioid administration in cancer patients have been subjected to investigations, and most studies have been engaged in assessment and treatment of the cerebral dysfunction. Early studies found that cancer patients in chronic oral opioid therapy had prolonged continuous reaction times, and that the opioids seemed to be mainly responsible for the prolongation. Significant dose escalations of opioids (≥ 30%) caused transiently impaired psychomotor and cognitive functions in cancer patients. Cancer patients in chronic oral opioid therapy did not achieve any advantages changing to epidural opioid therapy with regard to faster continuous reaction times and less pain.Large doses of opioids are often required to control severe pain in cancer patients. As increased sedation and impaired psychomotor and cognitive functions often occur, a number of studies have investigated the use of amphetamine derivatives to counteract the sedative side‐effects of opioid. These drugs seem promising during high‐dose opioid therapy and their use may be particularly rewarding in poor opioid‐responsive pain conditions such as incident and neuropathic pain.
Effects of dihydroergotamine and sumatriptan on isolated human cerebral and peripheral arteries and veins
Authors: NILSSON F. , NILSSON T. , EDVINSSON L. , BJÖRKMAN S. , NORDSTRÖM C.–H. 
Published: January 2009

Background: Pharmacological cerebral vasoconstriction has recently been suggested as treatment for patients with increased intracranial pressure (ICP) after severe traumatic brain lesions. Hypothetically, a moderate constriction of precapillary resistance vessels might be advantageous since it decreases intracapillary blood pressure, and a contraction of cerebral veins might effectively reduce intracranial blood volume and ICP. This report examines thein vitroeffects of two vasoconstrictors, dihydroergotamine (DHE) and sumatriptan, which may be considered for treatment of increased ICP.Methods: The reactivity of isolated small human cerebral, subcutaneous and omental arteries and veins were studied during exposure to different concentrations of DHE and sumatriptan.Results: Both sumatriptan and DHE induced concentration–dependent contractions in human cerebral arteries and veins and 50% of maximum contractions were obtained at significantly lower concentrations of DHE than of sumatriptan. The maximum contraction of cerebral arteries was significantly higher with sumatriptan than with DHE. Both drugs caused contractions of subcutaneous arteries at concentrations of 10‐7–10‐6M, which is within the therapeutic concentration range of sumatriptan, while no effect was obtained in omental vessels.Conclusions: Both DHE and sumatriptan cause contraction of isolated human cortical arteries and veins at very low concentrations. The differences observed between the two drugs may be explained by the fact that DHE is an α–adrenergic as well as a 5–HT agonist while sumatriptan acts specifically on 5–HT receptors. The study supports the hypothesis underlying the use of DHE for the treatment of increased ICP in patients with severe traumatic brain lesions.
Spinal, epidural or propofol anaesthesia for out–patient knee arthroscopy?
Authors: DAHL V. , GIERLØFF C. , OMLAND E. , RÆDER J. C. 
Published: January 2009

Background: We have compared three different methods of anaesthesia for out–patient knee arthroscopy in terms of perioperative conditions, postoperative pain, time taken and economy.Methods: 91 ASA I–II patients scheduled for elective knee arthroscopy were included. After premedication with diazepam 10 mg and naproxene 500 mg orally, they were randomly assigned into one of three groups: Group S (n=32) received spinal anaesthesia with lidocaine 50 mg/ml 1.5–2 ml in 7.5% glucose through a 27–G Quincke needle, Group E (n=29) received epidural anaesthesia with mepivacaine 20 mg/ml and epinephrine 5 μg/ml, 15–20 ml, and Group P (n=30) received propofol anaesthesia with a bolus induction of 2 mg/kg followed by infusion.Results: The time from start of anaesthesia until start of operation was significantly less in Group P than in the two other Groups: 7.45.4 min as compared to 23.04.8 min in Group S and 31.09.1 min in Group E (meanSD, P<0.05). After end of surgery, the duration of the postoperative regional block was 7528 min in Group S and 125 79 min in Group E (P<0.05). In Group S and Group E the postoperative pain was significantly less than in Group P at admission to the recovery unit and 60, 120 and 180 min later (P<0.05). The overall incidence of postoperative nausea or vomiting was less than 5% with no differences between the groups. One patient in Group E had block failure and one patient in Group S had a post–spinal headache. The perioperative costs of drugs and disposables were highest in Group P (30 USD) and lowest in Group S (6.5 USD).Conclusion: Propofol anaesthesia results in the shortest stay in the operation theatre but a higher degree of postoperative pain and a higher cost of drugs and disposables.
Intravenous induction of general anaesthesia with eltanolone in children 6–15 years of age
Authors: BESKOW A. , WERNER O. , WESTRIN P. 
Published: January 2009

Background:Eltanolone is a short‐acting intravenous anaesthetic, formulated as an oil‐water emulsion. The aim of the present study was to estimate the anaesthetic dose (ED50) for induction in children 6–10 and 11–15 years of age and to collect safety data.Methods:Forty‐nine unpremedicated children, all ASA I or II, divided in one pilot‐study group, with 5 children 6–15 years and two main study groups, 6–10 and 11–15 years of age, were studied. The first patient in each study group was given 0.86mg/kg of eltanolone iv over 20s. Fifty s after injection the chin was gently lifted to ‘the sniffing position’ and the anaesthesia mask was placed over the face. Induction was considered satisfactory if there was no gross movement, coughing or response to verbal command during the following 15s. The dose selected for the next patient was based on the observed response: if induction was not classified as satisfactory the dose was increased by a factor of 20%, otherwise it was decreased by the same factor. ED50was estimated as described by Dixon and Massey.Results:In children 6–10 years of age ED50was 0.68 (0.49‐0.92; 95% confidence limits) mg/kg and in children 11–15 years of age 0.53 (0.41‐0.68) mg/kg. No child showed sign of pain on injection. One patient developed urticaria and 15 patients had transient rash after induction. Two patients (both responders receiving 0.86 and 0.40mg/kg respectively) had apnoea lasting more than 15 s. Involuntary movements occurred in one patient.Conclusions:The ED50of eltanolone for induction of anaesthesia in unpremedicated children 6–10 years of age was 0.68 mg/kg and in children 11–15 years of age 0.53 mg/kg. The findings suggest that an induction dose for children 6–15 years of age of about l mg/kg would be adequate in most cases. No serious adverse events were recorded. However, the drug has subsequently been withdrawn from further investigation due to an unacceptable incidence of rash and urticaria.
Hepatic energy charge and adenine nucleotide status in rats anesthetized with halothane, isoflurane or enflurane
Authors: METS B. , JANICKI P. K. , JAMES M. F. M. , HICKMAN R. 
Published: January 2009

Background:Volatile anesthetics are known to have varying effects on hepatic oxygen supplyin vivoand have been shown to depress hepatic mitochondrial respiration and so energy chargein vitro.However, the effect of halothane, isoflurane and enflurane on hepatic adenine nucleotide statusin viuohas not been evaluated.Methods:Ninety male rats were exposed to 40% oxygen (n=22) or 40% oxygen in equipotent (1 MAC) concentrations of halothane (1%) (n=23), isoflurane (1.4%) (n=22) or enflurane (2%) (n=23) for 2 hours. All animals were then administered intraperitoneal pentobarbital and anesthesia continued and laparotomy was performed. A liver biopsy was taken for determination of hepatocellular adenosine‐5‐triphosphate (ATP), adenosine‐5‐diphosphate (ADP) and adenosine‐5‐monophosphate (AMP) and computation of energy charge (EC) from ((ATP+1/2 ADP)+(ATP+ADP+AMP)) and total ade nine nucleotides (TAN) from (ATP+ADP+AMP). After the biopsy the aorta was cannulated for blood sampling.Results:Rats in each group were similar in weight, as well as acid base and blood gas status just after liver biopsy. Hepatic energy charge, ATP, ADP, AMP, and TAN levels were not different in animals receiving either halothane, isoflurane or enflurane when compared with those receiving only oxygen.Conclusions:One MAC of anesthesia for a period of 2 hours with the described volatile anesthetic agents did not affect adenine nucleotide statusin viuoin rats.
Metoclopramide reduces the induction dose of propofol
Authors: PAGE V. J. , CHHIPA J. H. 
Published: January 2009

Background:Metoclopramide has been shown to reduce the dose of thiopentone required for induction of anaesthesia. When propofol is used, there have been conflicting results with one small study showing a reduction in the anaesthetic dose and one study failing to demonstrate any effect.Methods:Two groups of 30 patients were studied. The patients were randomised to receive either saline 0.03 ml/mg or metoclopramide 0.15 mg/kg 5 min before a manual injection of propofol at a set rate.Results:This study shows a reduction in the dose of propofol required for the induction of general anaesthesia following an intravenous dose of metoclopramide. The induction dose of propofol was reduced by 24%.Conclusions:The mechanism of reduction of propofol dose by metoclopramide is unknown; it may involve GABA or result from a more complex interaction involving dopamine blockade by metoclopramide.
Delayed elevation of plasma endothelin‐1 during unilateral alveolar hypoxia without systemic hypoxemia in humans
Authors: TAKEDA S. , NAKANISHI K. , INOUE T. , OGAWA R. 
Published: January 2009

Background:The mechanisms by which acute alveolar hypoxia induces pulmonary vasoconstriction remain unclear. We investigated whether endothelin‐1 (ET‐1) could be detected in plasma during pulmonary alveolar hypoxia without systemic hypoxemia (one‐lung hypoxia) and whether the levels could be related to hemodynamic status in humans.Methods: Thirteen adult patients with primary lung carcinoma were studied prior to surgery. Anesthesia was induced with fentanyl, diazepam, and pancuronium iv. Differential lung ventilation was performed for 40 min. The right lung was ventilated with a mixture of 6% O2, 5% CO2 and 89% N2 and the left lung ventilated with 100% O2. Blood gas values, hemodynamic parameters, and plasma ET‐1 levels were measured.Results: Mean pulmonary artery pressure increased from 13.±3.5 to 17.·3.2mm Hg (P <0.01) after 20 min of one‐lung hypoxia. The plasma ET‐1 levels in arterial blood and wedged right pulmonary arterial blood increased from 1.69M.61 to 2.13 ±0.48 μg/ml (P <0.01) and from 1.75±.47 to 2.26±.40 μg/ ml (P <0.001), respectively, after 40 min of one‐lung hypoxia.Conclusions: We concluded that ET‐1 may play a supporting, but not a primary, role in human hypoxic pulmonary vasoconstriction.
Myocardial cooling and right ventricular function in patients with right coronary artery disease: antegrade vs. retrograde cardioplegia
Authors: HONKONEN E. L. , KAUKINEN L. , PEHKONEN E. J. , KAUKINEN S. 
Published: January 2009

Background: Protection of the right ventricular (RV) myocardium during ischaemia in cardiac surgery is difficult, especially in patients with severe right coronary artery (RCA) disease. Retrograde coronary sinus cardioplegia is thought to distribute uniformly, but doubts still remain as to its adequacy in RV preservation. This study evaluated distribution of antegrade vs. exclusively retrograde coronary sinus cold blood cardioplegia by assessing myocardial cooling and compared the effects on RV function.Methods: Fifty‐eight patients scheduled for elective coronary artery surgery ‐ 29 patients with significant RCA disease and another 29 with no significant RCA stenosis (controls) ‐ were randomised to receive either antegrade or retrograde cold blood cardioplegia through either aortic root or conventional self‐inflating coronary sinus catheter (RCA‐ante, RCA‐retro, C‐ante and C‐retro groups). RV function was assessed by fast‐response thermodilution. Myocardial temperatures were measured in the anterior and posterior wall of the right and left ventricle.Results: Cooling of the posterior wall of the RV was effective only in the control patients given antegrade cardioplegia (14.7°C), whereas in the other groups the lowest myocardial temperatures there remained above 20°C (RO.001). In patients with obstructed RCA both antegrade and retrograde cold cardioplegia led to uneven cooling of the myocardium. After cardiopulmonary bypass the RV ejection fraction (RVEF), RV stroke work index (RVSWI) and cardiac index (CI) were significantly reduced in the RCA‐retro group, and RVSWI and CI in the C‐retro group, too. Regression analysis showed an inverse relationship between the temperatures of the posterior walls of the ventricles and changes in the RVEF and CI.Conclusions: Retrograde and antegrade cardioplegia alone were not effective in reducing the temperature of the posterior wall of the RV in the patients with obstructed RCA, in whom with retrograde cardioplegia RV haemodynamics were impaired for 1 hour following bypass. Neither retrograde nor antegrade cardioplegia alone can be relied on to protect the posterior wall of the RV in the patients with obstructed RCA.