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We discuss the generalized Newton-Cartan geometries that can serve as gravitational background fields for particles and strings. In order to enable us to define affine connections that are invariant under all the symmetries of the structure group, we describe torsionful geometries with independent torsion tensors. A characteristic feature of the non-Lorentzian geometries we consider is that some of the torsion tensors are so-called `intrinsic torsion' tensors that cannot be absorbed in any of the spin connections. Setting some components of these intrinsic torsion tensors to zero leads to constraints on the geometry. For both particles and strings, we discuss various such constraints that can be imposed consistently with the structure group symmetries. In this way, we reproduce several results in the literature., 26 pages, comments are welcome

Evidence is accumulating that both perioperative anemia and packed red blood cell transfusions are associated with adverse outcomes after cardiac surgery. Jehovah’s Witnesses who categorically refuse blood products, while otherwise expecting the highest standards of medical care and full deployment of modern medical technology, constitute a particular challenge for cardiac surgery. Their cases are interesting because they provide additional material to evaluate blood conservation strategies and advantages and risks of blood transfusion in cardiac surgery.

The aim of this retrospective study was to compare the utilisation of blood products and outcomes following cardiac surgery for 123 Jehovah's Witnesses and 4219 non-Jehovah's Witness patient controls. The study took place over a 7-year period at the Amphia Hospital in Breda, the Netherlands. A specific protocol was used in the management of Jehovah's Witness patients, while the control group received blood without restriction according to their needs. Patients' characteristics were comparable in both groups. Pre-operatively, the mean (SD) Euro Score was higher in the Jehovah's Witness group (3.2 (2.6) vs 2.7 (2.5), respectively; p < 0.02). Pre-operative haemoglobin concentration was higher in the Jehovah's Witness group (8.9 (0.7) vs 8.6 (0.9) g.dl(-1), respectively; p < 0.001). The total cardiopulmonary bypass time did not differ between groups. The requirement for allogenic blood transfusion was 0% in the Jehovah's Witness group compared to 65% in the control group. Postoperatively, there was a lower incidence of Q-wave myocardial infarction (2 (1.8%) vs 323 (7.7%), respectively; p < 0.02), and non Q-wave infarction (11 (9.8%) vs 559 (13.2%), respectively; p < 0.02) in the Jehovah's Witness group compared with controls. Mean (SD) length of stay in the intensive care unit (2.3 (3.2) vs 2.6 (4.2) days; p = 0.26), re-admission rate to the intensive care unit (5 (4.5%) vs 114 (2.7%); p = 0.163), and mortality (3 (2.7%) vs 65 (1.5%); p = 0.59), did not differ between the Jehovah's Witness and control groups, respectively.

We give a short overview of Newton–Cartan geometry and gravity including its matter couplings. We also present results on a new non-relativistic gravity model in three spacetime dimensions, called extended Bargmann gravity, and show that this model has matter couplings that differ from those of Newton–Cartan gravity.

Item does not contain fulltext BACKGROUND AND OBJECTIVE: Sevoflurane has been used for the induction and maintenance of anaesthesia during cardiac surgery owing to its favourable haemodynamic effects. It has been suggested that it offers protection against myocardial ischaemia-reperfusion injury. METHODS: We investigated the effect of sevoflurane on plasma concentrations of tumour necrosis factor-alpha (TNF-alpha) after ex vivo stimulation of whole-blood leukocytes by lipopolysaccharide from 20 patients undergoing coronary artery bypass surgery. The patients were randomized to two groups. Group 1 patients were induced and maintained with sevoflurane; those in Group 2 were anaesthetized with moderate doses of midazolam-sufentanil. Blood samples were drawn from the patients on seven occasions from before induction of anaesthesia until 24 h after skin closure. RESULTS: Plasma concentrations of TNF-alpha were lower in Group 1 than in Group 2 after cessation of cardiopulmonary bypass (median (interquartiles): 25 (21-30) versus 37 (28-79) pg mL(-1); P < 0.05) and 24h after skin closure (196 (100-355) versus 382 (233-718) pg mL(-1); P < 0.05). Postoperatively, two cases of myocardial infarction were recorded, one in each group. Six patients in Group 2 needed continued inotropic support after the first morning to maintain haemodynamic stability versus one patient in Group 1 (P < 0.05). The length of stay in the intensive care unit was significantly lower in Group 1 than in Group 2 (mean +/- SD: 25 +/- 16 versus 54 +/- 30 h; P < 0.05). CONCLUSIONS: Sevoflurane reduces production of TNF-alpha more than total intravenous anaesthesia with midazolam-sufentanil during cardiac surgery. This may reduce cardiac morbidity and the length of stay in the intensive care unit.

Supplementary oxygen is commonly administered in current medical practice. However, attention has recently been drawn to the potentially disadvantageous hemodynamic consequences in certain patients. Possible mechanisms underlying the cardiovascular responses to acute hyperoxia are unclear. The effects of acute oxygen administration on heart rate, blood pressure, cardiac output, systemic vascular resistance, and baroreflex sensitivity were studied in a series of randomised, placebo-controlled studies in healthy individuals, using validated, non-invasive techniques. The effects of oxygen administration on forearm blood flow responses to locally administered acetylcholine, an endothelium-dependent vasodilator, sodium nitroprusside, an endothelium-independent vasodilator, and l-NG-monomethylarginine, a nitric oxide synthase inhibitor, were studied using venous occlusion plethysmography. Oxygen administration for 1 hour caused a reduction in heart rate (P0.01) and cardiac index (P0.05), and an increase in mean arterial pressure (P0.01), systemic vascular resistance (P0.05), large artery stiffness (P0.05), and baroreflex sensitivity (P0.05). There were no effects on vascular responses in the isolated forearm bed. These findings indicate that oxygen administration causes acute effects on cardiovascular function, which might be important in the context of acute illness.

Cytokines regulate inflammation associated with cardiopulmonary bypass (CPB). Pro-inflammatory cytokines may cause myocardial dysfunction and haemodynamic instability after CPB, but the release of anti-inflammatory cytokines is potentially protective. We studied the effects of dexamethasone on pro- and anti-inflammatory cytokine responses during coronary artery bypass grafting surgery.Seventeen patients were studied: nine patients received dexamethasone 100 mg before induction of anaesthesia (group 1) and eight patients acted as controls (group 2). Plasma levels of tumour necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-8, IL-10 and IL-4 were measured perioperatively.TNF-alpha and IL-8 did not increase significantly in group 1 whereas they increased in group 2 to greater than preoperative values (P0.05). IL-6 increased in both groups, with lower values in group 1 than in group 2 (P0.05). IL-10 increased in both groups, with higher values in group 1 (P0.05). IL-4 did not change in group 1 but decreased in group 2 compared with pre-induction values (P0.05). After surgery, patients in group 2 had tachycardia, hyperthermia, a greater respiratory rate and higher pulmonary artery pressure, and a longer stay in the intensive care unit.Dexamethasone given before cardiac surgery changes circulating cytokines in an anti-inflammatory direction. Postoperative outcome may be improved by inhibition of the systemic inflammatory response.

Objective: To compare the efficacy and safety of dopexamine with dopamine in the treatment of low cardiac output syndrome after cardiac surgery. Design: This was a multicentre, double-blind, randomised, parallel-group study conducted in intensive care units at centres in Holland and Belgium. Patients were randomised to receive dopexamine (up to 2.0 μg/kg per min) or dopamine (up to 6.0 μg/kg per min) for 6 h after low cardiac output syndrome was confirmed. Results: 70 patients were enrolled (35/group) and there was no significant difference in the operative procedures or haemodynamics at entry into the study. Clinical efficacy, defined as a cardiac index > 2.5 l/min per m2 with urine production > 0.5 ml/kg per h and stable haemodynamics for two consecutive readings 1 h apart, was achieved by 90 and 87 % of patients in the dopexamine and dopamine groups, respectively. However, more patients maintained clinical efficacy over the 6-h period in the dopexamine group, which was statistically significant at 1–2 h and approached significance at all other time points. Safety was assessed by comparing the adverse events and concomitant medication. Fewer patients on dopexamine had cardiac events compared with dopamine-treated patients (25 vs 38 events), although there was no difference in the pattern of rhythm disturbance. Fewer patients in the dopexamine group required concomitant vasodilating drugs (18 vs 30). Conclusion: Taking the proportion of patients achieving clinical efficacy, the time to achieve it and the maintenance of it along with the adverse event profile, dopexamine was shown to be an effective and safe drug to use in the management of low cardiac output syndrome after coronary artery bypass graft surgery and may be superior to dopamine.

Non-invasive cardiac output measurement by means of impedance cardiography has been evaluated before, and agreement with other methods has been variable. We decided to study a newly developed tracheal impedance device, that is claimed to be more accurate and reliable. This incorporates new software and mathematical formulae, that are designed to reduce signal noise from diathermy, leading to improved accuracy. In 25 cardiothoracic surgery patients, simultaneous measurements were performed using both pulmonary artery thermodilution and the tracheal impedance device, at five peri-operative time points: before skin incision; after weaning from cardiopulmonary bypass; after sternal closure; and 30 min and 2 h after arrival in the intensive care unit. Mean cardiac output, bias and 95% limits of agreement were 5.3, 0.03 and -2.8 to 2.8 l.min(-1) , respectively. Tracheal impedance showed good correlation with measurement trends using thermodilution in 88% of measurements, with a mean (95% limit of agreement) angular bias of -9.0° (-83.3 to 65.3°). However, the wide limits of agreement and high percentage error of 53% that were apparent in this study mean that, in its present guise, tracheal impedance is not an acceptable alternative to thermodilution in cardiac surgical patients.

The aim of this retrospective study was to compare the utilisation of blood products and outcomes following cardiac surgery for 123 Jehovah's Witnesses and 4219 non-Jehovah's Witness patient controls. The study took place over a 7-year period at the Amphia Hospital in Breda, the Netherlands. A specific protocol was used in the management of Jehovah's Witness patients, while the control group received blood without restriction according to their needs. Patients' characteristics were comparable in both groups. Pre-operatively, the mean (SD) Euro Score was higher in the Jehovah's Witness group (3.2 (2.6) vs 2.7 (2.5), respectively; p0.02). Pre-operative haemoglobin concentration was higher in the Jehovah's Witness group (8.9 (0.7) vs 8.6 (0.9) g.dl(-1), respectively; p0.001). The total cardiopulmonary bypass time did not differ between groups. The requirement for allogenic blood transfusion was 0% in the Jehovah's Witness group compared to 65% in the control group. Postoperatively, there was a lower incidence of Q-wave myocardial infarction (2 (1.8%) vs 323 (7.7%), respectively; p0.02), and non Q-wave infarction (11 (9.8%) vs 559 (13.2%), respectively; p0.02) in the Jehovah's Witness group compared with controls. Mean (SD) length of stay in the intensive care unit (2.3 (3.2) vs 2.6 (4.2) days; p = 0.26), re-admission rate to the intensive care unit (5 (4.5%) vs 114 (2.7%); p = 0.163), and mortality (3 (2.7%) vs 65 (1.5%); p = 0.59), did not differ between the Jehovah's Witness and control groups, respectively.

Prognostic models are tools to predict the outcome of disease and disease treatment. These models are traditionally built with supervised machine learning techniques, and consider prognosis as a static, one-shot activity. This paper presents a new type of prognostic model that builds on the Bayesian network methodology that implements a dynamic, process-oriented view on prognosis. In contrast to traditional prognostic models, prognostic Bayesian networks explicate the scenarios that lead to disease outcomes, and can be used to update predictions when new information becomes available. A recursive data analysis strategy for inducing prognostic Bayesian networks from medical data is presented, and applied to data from the field of cardiac surgery. The resulting model outperformed a model that was constructed with off-the-shelf Bayesian network learning software, and had similar performance as class probability trees.

A prognostic Bayesian network (PBN) is new type of prognostic model that implements a dynamic, process-oriented view on prognosis. In a companion article, the rationale of the PBN is described, and a dedicated learning procedure is presented. This article presents an application here of in the domain of cardiac surgery. A PBN is induced from clinical data of cardiac surgical patients using the proposed learning procedure; hospital mortality is used as outcome variable. The predictive performance of the PBN is evaluated on an independent test set, and results were compared to the performance of a network that was induced using a standard algorithm where candidate networks are selected using the minimal description length principle. The PBN is embedded in the prognostic system ProCarSur; a prototype of this system is presented. This application shows PBNs as a useful prognostic tool in medical processes. In addition, the article shows the added value of the PBN learning procedure.

Prognostic models are tools to predict the future outcome of disease and disease treatment, one of the fundamental tasks in clinical medicine. This article presents the prognostic Bayesian network (PBN) as a new type of prognostic model that builds on the Bayesian network methodology, and implements a dynamic, process-oriented view on prognosis. A PBN describes the mutual relationships between variables that come into play during subsequent stages of a care process and a clinical outcome. A dedicated procedure for inducing these networks from clinical data is presented. In this procedure, the network is composed of a collection of local supervised learning models that are recursively learned from the data. The procedure optimizes performance of the network's primary task, outcome prediction, and handles the fact that patients may drop out of the process in earlier stages. Furthermore, the article describes how PBNs can be applied to solve a number of information problems that are related to medical prognosis.

Background The study evaluated the efficacy of recombinant human antithrombin (rhAT) for restoring heparin responsiveness in heparin resistant patients undergoing cardiac surgery. Methods This was a multicenter, randomized, double-blind, placebo-controlled study in heparin-resistant patients undergoing cardiac surgery with cardiopulmonary bypass. Heparin resistance was diagnosed when the activated clotting time was less than 480 s after 400 U/kg heparin. Fifty-four heparin-resistant patients were randomized. One cohort received 75 U/kg rhAT, and the other received normal saline. If the activated clotting time remained less than 480 s, this was considered treatment failure, and 2 units fresh frozen plasma was transfused. Patients were monitored for adverse events. Results Only 19% of patients in the rhAT group received fresh frozen plasma, compared with 81% of patients in the placebo group (P < 0.001). During their hospitalization, 48% of patients in the rhAT group received fresh frozen plasma, compared with 85% of patients in the placebo group (P = 0.009). Patients in the placebo group required higher heparin doses (P < 0.005) for anticoagulation. There was no increase in serious adverse events associated with rhAT. There was increased blood loss 12 h postoperatively (P = 0.05) with a trend toward increased 24-h bleeding in the rhAT group (P = 0.06). There was no difference between the groups in blood and platelet transfusions. Conclusion Treatment with 75 U/kg rhAT is effective in restoring heparin responsiveness and promoting therapeutic anticoagulation in the majority of heparin-resistant patients. Treating heparin-resistant patients with rhAT may decrease the requirement for heparin and fresh frozen plasma.

Background and objective Cardiac surgery with cardiopulmonary bypass triggers an inflammatory response involving pro-inflammatory cytokines such as tumour necrosis factor-alpha (TNF-alpha), interleukin 6 (IL-6) and interleukin 8 (IL-8). We investigated whether different anaesthetic techniques alter the pro-inflammatory cytokine response to cardiac surgery. Methods Thirty patients scheduled for elective coronary artery bypass grafting (CABG) surgery were randomized into three groups of 10 patients. They received either volatile inhalation induction and maintenance (Group 1) or total intravenous anaesthesia with propofol and a minimal dose sufentanil (Group 2) or a moderate dose midazolam-sufentanil (Group 3). The effect of the different anaesthetic techniques on plasma levels of TNF-alpha, IL-6 and IL-8 were examined during and after anaesthesia. Results Concentrations of TNF-alpha, and IL-8 were comparable in the three groups throughout all measurements. Before the start of cardiopulmonary bypass, IL-6 was significantly higher in Group 1 than in Group 2 (P = 0.009) or Group 3 (P = 0.030), but there were no differences between groups after cardiopulmonary bypass or postoperatively. In the three groups there was a positive correlation between aortic clamping time and serum concentrations of IL-6 (r = 0.54) and IL-8 (r = 0.62). Length of stay in intensive care was correlated with high levels of TNF-alpha (r = 0.78). Conclusions Albeit there is difference between the volatile induction and maintenance of the anaesthesia method and the total intravenous anaesthesia technique on the pro-inflammatory cytokine response to surgical stimulation before starting of cardiopulmonary bypass, neither technique can modify the pro-inflammatory cytokine response to ischaemia-reperfusion or extracorporeal circulation.

We discuss general actions for matter-coupled N = 1 supergravity, that include generalized Chern-Simons terms. We clarify the importance of these terms in ensuring gauge and supersymmetry invariance in case axionic shift symmetries are gauged. We also indicate the interplay of Peccei-Quinn terms, generalized Chern-Simons terms and anomalies in the context of N = 1 supergravity.

A comparative study was undertaken to evaluate the effectiveness of epidural sufentanil in providing intra- and postoperative analgesia during thoracic surgery. Sufentanil was chosen on the basis of its high lipid solubility and its potent opiate receptor binding. Epidural sufentanil was compared with intravenous sufentanil as the major intraoperative analgetic agent in an anesthesia regimen with midazolam and nitrous oxide. Epidural sufentanil significantly decreased the need for supplementary intravenous analgesia. In the epidural sufentanil group the immediate postoperative analgesia was found to be better, with a longer duration of action, compared with the intravenous sufentanil group. Postoperatively epidural sufentanil was compared with epidural morphine. Sufentanil provided good analgesia with a very fast onset and a mean duration of almost 7 h. Severe respiratory depression was observed in one patient within 1 h of extubation, probably due to the combined effects of the narcotic administration and residual midazolam. It is concluded that 50 micrograms of sufentanil administered in the thoracic epidural space provides valuable intraoperative analgesia which can easily be extended into the postoperative period, although all necessary precautions for epidural opiate administration should be taken.

Although nitrous oxide is commonly administered to patients with ischemic heart disease, recent reports suggest that it may induce myocardial ischemia in these patients. The authors compared the effects of nitrous oxide on segmental left ventricular (LV) function and the ST segment of the electrocardiogram with the effects of an equal concentration of nitrogen (crossover design) before the start of surgery in 18 patients who required coronary-artery bypass grafting. The patients studied did not have valvular or LV dysfunction. Anesthesia was induced and maintained with intravenous fentanyl. After endotracheal intubation and 20 min of ventilation with 100% oxygen, either 60% nitrous oxide or 60% nitrogen (randomly assigned) was added to the inspired gas mixture of each patient for 10 min. This was followed by 10 min of 100% oxygen, and then 10 min of 60% nitrous oxide or 60% nitrogen, whichever had not been administered previously. Patients were monitored for myocardial ischemia using a standard 12-lead electrocardiogram and trans-esophageal two-dimensional echocardiography. Surgery did not begin until the study was concluded. No patient experienced an ST segment change greater than 1 mm during the study, and none developed a new segmental wall motion abnormality during inhalation of either nitrous oxide or nitrogen. The authors conclude that nitrous oxide does not induce myocardial ischemia when used as an adjunct to fentanyl anesthesia in patients who have severe coronary-artery disease accompanied by well-preserved valvular and LV function.