The Role of Fish Oil Feeding Rich in ω‐3 Polyunsaturated Fatty Acids in Patients with Sepsis and Septic Shock

Different clinical studies have demonstrated that fish oil, rich in the very‐long‐chain ω‐3 polyunsaturated fatty acids (PUFAs), has immunomodulatory effects, suppressing the production of pro‐inflammatory cytokines in diverse groups of critically ill patients. Moreover, such compounds have been found to attenuate the inflammatory response within 2–3 days upon parenteral administration. Recent experimental data suggest that activation of the cholinergic anti‐inflammatory pathway constitutes a novel mechanism of such immune‐regulatory effects. Since enhanced vagal tone has been associated with decreased cytokine secretion, novel monitoring tools of its activity at the bedside are needed, in order to evaluate nutritional manipulation of inflammatory response in the critically ill. The present chapter provides an overview of the mechanisms of action through which ω‐3 PUFA modulates immune response in critically ill patients suffering from sepsis and septic shock. Furthermore, it summarizes the current evidence regarding clinical effects from administration of fish oil rich in ω‐3 PUFAs in septic patients. Finally, it presents data that suggest the existence of a continuous interrelation between immune status and autonomic nervous system during systemic inflammation and proposes novel tools of autonomic nervous system monitoring at the bedside, in order to assess pharmacological manipulation of immune response by ω‐3 PUFAs in acute illness

A numerical study of flow-structure interactions with application to flow past a pair of cylinders

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 2004.Includes bibliographical references (v. 2, p. 587-601).Flow-structure interaction is a generic problem for many engineering applications, such as flow--induced oscillations of marine risers and cables. In this thesis a Direct Numerical Simulation (DNS) approach based on spectral/hp elements is employed. Structural motion implies changes on the boundaries of the flow domain. An Arbitrary Lagrangian Eulerian (ALE) scheme is incorporated to efficiently move the mesh without remeshing. Efficient three-dimensional simulations with periodicity in at least one space direction are achieved using Hybrid Fourier-Jacobi expansions. Both 2D and 3D formulations can treat an arbitrary number of oscillating bodies. Due to the large computational demands of the resulting systems parallel computing is used with MPI. Numerical experiments are run and systematic data sets are obtained for flow around two cylinders. Stationary cylinders in tandem and side-by-side arrangements are examined parametrically over spacing and Reynolds number. Parametric studies of tandem cylinders in prescribed motion and free oscillation are also conducted. For tandem cylinders, sudden changes in the forces occur at a critical spacing where a transition from reattachment to binary vortex regime occurs.(cont.) A hysteresis effect is observed for spacings near the nominal critical, where for given Reynolds number there are two possible solutions depending on the initial conditions. Discrepancies in the prediction of the critical spacing using 2D and 3D simulations are identified and explained. The three-dimensional effects are found to cause a weakening of the strength of the primary vortices and a delay in the inception to) binary vortex regime. When the cylinders oscillate in prescribed motion, the phase angle of the oscillations can alter significantly the hydrodynamic work on the downstream cylinder. For spacings smaller than the critical spacing, the lock-on range of frequencies is wider than that of a single cylinder. As the oscillations amplitude increases however, pockets of non-lock-on regions are found within the Arnold synchronization regions. A shift towards higher frequencies in the synchronization range is found for the in-phase oscillations compared to the anti-phase oscillations. A consistent change is found in the spanwise correlations. For the elastically mounted two-degree of freedom tandem cylinders it is found that the synchronization range of the upstream cylinder is wider when its latest shed pair of vortices intercepts the downstream cylinder.(cont.) A shifting of the synchronization curve on the reduced velocity axis is observed and explained in terms of the natural shedding frequency of the corresponding stationary system of cylinders.by Georgios V. Papaioannou.Ph.D

A step-by-step diagnosis of exclusion in a twin pregnancy with acute respiratory failure due to non-fatal amniotic fluid embolism: a case report

<p>Abstract</p> <p>Introduction</p> <p>Respiratory failure may develop during the later stages of pregnancy and is usually associated with tocolysis or other co-existing conditions such as pneumonia, sepsis, pre-eclampsia or amniotic fluid embolism syndrome.</p> <p>Case presentation</p> <p>We present the case of a 34-year-old healthy woman with a twin pregnancy at 31 weeks and 6 days who experienced acute respiratory failure, a few hours after administration of tocolysis (ritodrine), due to preterm premature rupture of the membranes. Her chest discomfort was significantly ameliorated after the ritodrine infusion was stopped and a Cesarean section was performed 48 hours later under spinal anesthesia; however, 2 hours after surgery she developed severe hypoxemia, hypotension, fever and mild coagulopathy. The patient was intubated and transferred to the intensive care unit where she made a quick and uneventful recovery within 3 days. As there was no evidence for drug- or infection-related thromboembolic or myocardial causes of respiratory failure, we conclude that our patient experienced a rare type of non-fatal amniotic fluid embolism.</p> <p>Conclusion</p> <p>In spite of the lack of solid scientific support for our diagnosis, we conclude that our patient suffered an uncommon type of amniotic fluid embolism syndrome and we believe that this report highlights the need for extreme vigilance and a high index of suspicion for such a diagnosis in any pregnant individual.</p

Association of transcranial Doppler blood flow velocity slow waves with delayed cerebral ischemia in patients suffering from subarachnoid hemorrhage: a retrospective study.

BACKGROUND: Cerebral vasospasm (VS) and delayed cerebral ischemia (DCI) constitute major complications following subarachnoid hemorrhage (SAH). A few studies have examined the relationship between different indices of cerebrovascular dynamics with the occurrence of VS. However, their potential association with the development of DCI remains elusive. In this study, we investigated the pattern of changes of different transcranial Doppler (TCD)-derived indices of cerebrovascular dynamics during vasospasm in patients suffering from subarachnoid hemorrhage, dichotomized by the presence of delayed cerebral ischemia. METHODS: A retrospective analysis was performed using recordings from 32 SAH patients, diagnosed with VS. Patients were divided in two groups, depending on development of DCI. Magnitude of slow waves (SWs) of cerebral blood flow velocity (CBFV) was measured. Cerebral autoregulation was estimated using the moving correlation coefficient Mxa. Cerebral arterial time constant (tau) was expressed as the product of resistance and compliance. Complexity of CBFV was estimated through measurement of sample entropy (SampEn). RESULTS: In the whole population (N = 32), magnitude of SWs of ipsilateral to VS side CBFV was higher during vasospasm (4.15 ± 1.55 vs before: 2.86 ± 1.21 cm/s, p < 0.001). Ipsilateral SWs of CBFV before VS had higher magnitude in DCI group (N = 19, p < 0.001) and were strongly predictive of DCI, with area under the curve (AUC) = 0.745 (p = 0.02). Vasospasm caused a non-significant shortening of ipsilateral values of tau and increase in SampEn in all patients related to pre-VS measurements, as well as an insignificant increase of Mxa in DCI related to non-DCI group (N = 13). CONCLUSIONS: In patients suffering from subarachnoid hemorrhage, TCD-detected VS was associated with higher ipsilateral CBFV SWs, related to pre-VS measurements. Higher CBFV SWs before VS were significantly predictive of delayed cerebral ischemia

A cadaveric study of anatomical variations of the normal arterial pattern in hellenic population

Introduction. Arterial variations may cause significant complications during diagnostic and interventional procedures. The objective of the study. Our study examined 73 donated cadavers in the National and Kapodistrian University of Athens, in an effort to unearth possible artery alternations. Material and methods. The major branches of the abdominal aorta, the arteries of the limps and the neck were inquired. Results. In 58.9% of the cadavers no arterial variation was found, whereas one, two and three alternations at the same cadaver were observed in 21.9%, 12.3% and 6.8% respectively. The most common anatomical variations were noted in the vascular branching of the celiac trunk found in 24.7% of the cadavers. Conclusions. There was no statistically significant difference between the two genders concerning the frequency of the observed arterial variations (p<0.05)

A fatal case of recurrent amiodarone-induced thyrotoxicosis after percutaneous tracheotomy: a case report

<p>Abstract</p> <p>Background</p> <p>Amiodarone is a widely used antiarrythmic drug, which may produce secondary effects on the thyroid. In 14–18% of amiodarone-treated patients, there is overt thyroid dysfunction, usually in the form of amiodarone-induced thyrotoxicosis, which can be difficult to manage with standard medical treatment.</p> <p>Case presentation</p> <p>Presented is the case of a 65-year-old man, under chronic treatment of atrial fibrillation with amiodarone, who was admitted to the Intensive Care Unit with acute cardio-respiratory failure and fever. He was recently hospitalized with respiratory distress, attributed to amiodarone-induced pulmonary fibrosis. Clinical and laboratory investigation revealed thyrotoxicosis due to amiodarone treatment. He was begun on thionamide, prednisone and beta-blockers. After a short term improvement of his clinical status the patient underwent percutaneous tracheotomy due to weaning failure from mechanical ventilation, which led to the development of recurrent thyrotoxicosis, unresponsive to medical treatment. Finally, the patient developed multiple organ failure and died, seven days later.</p> <p>Conclusion</p> <p>We suggest that percutaneous tracheotomy could precipitate a thyrotoxic crisis, particularly in non-euthyroid patients suffering from concurrent severe illness and should be performed only in parallel with emergency thyroid surgery, when indicated.</p