Oxidative Stress and Cardiovascular Dysfunction in Sepsis

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A state of severe oxidative stress and cardiovascular dysfunction are both associated with the dysregulated immuno-inflammatory response encountered in sepsis. The hemodynamic changes seen are typically a reduction in vascular tone and myocardial depression, accompanied by a preserved or increased cardiac output. Inflammatory mediators (including cytokines, endothelial-derived factors, and reactive oxygen species), regulated by nuclear factor kappa B, appear to have an integral role in mediating this cardiovascular dysfunction. This review gives a background to the oxidative stress encountered in sepsis, together with an overview of the proposed mechanisms underlying the cardiovascular dysfunction in sepsis and the role which reactive oxygen species and oxidative stress appear to have in its pathogenesis. The results of endogenous antioxidant repletion and synthetic antioxidant administration in sepsis and their effects on the cardiovascular dysfunction seen are reviewed. The role of more direct superoxide anion inhibition is also highlighted.

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Energy, Trace Element And Vitamin Requirements in Major Burns

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Nutritional management of patients with severe burn injuries remains a challenge for the clinician. Energy requirements are increased for prolonged periods of time. Substrate flux is accelerated. Catabolism is strongly enhanced, resulting in the loss of lean body mass: full nutritional support is unable to reverse this process. Increasing protein and carbohydrate intakes above respectively 1.3 g/kg/d and 4 mg/kg/min has no proven metabolic benefit. On the contrary, high intakes of carbohydrates and prolonged hypernutrition result in increased de novo lipogenesis, with the risk of developing liver complications like fatty liver infiltration. Strategies to reduce energy expenditure have been developed including early surgery, warm environment, pharmacological treatments (beta-blockade). Trace element and vitamin needs are also strongly increased. The micronutrients have particularly important antioxidant functions after major burns: they contribute to the reduction of lipid peroxidation, to the immune defence, and are essential in most anabolic pathways. There are strongly increased requirements for copper, selenium, zinc, alpha-tocopherol and ascorbic acid. The optimal route for nutrition is the gut, gastric and postpyloric accesses being possible. Enteral nutrition should be used first, and started during the first 24 hours of injury, but parenteral nutrition should not be excluded in patients intolerant to this feeding mode.

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Resuscitation in The Bible

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The Bible is occasionally cited as the source of written descriptions of the earliest instances of resuscitation. A number of accounts of recovery from death are found in the Bible. Two Old Testament episodes that appear to describe resuscitation are related in the books of Kings, and involve the Hebrew prophets Elijah and Elisha. The story of Elisha, Elijah’s successor as Prophet of Israel, is the one most frequently cited in medical articles as representing the earliest documented case of mouth-to-mouth resuscitation. The opinions of biblical and medical scholars differ on this point. Another episode that may represent resuscitation is told in the New Testament, and regards an action by the Apostle Paul. Within a century of this episode, the investigations of Galen marked the dawning of a new era in medical inquiry that was ultimately to lay the scientific foundations of resuscitation. However, episodes from the Bible had already served to display the possibility that resuscitation could be achieved.

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Ventilator – Associated Pneumonia: Pathophysiology, Diagnosis, and Treatment

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Ventilator Associated Pneumonia (VAP) is a common and important problem in the ICU. It affects approximately 25 % of ICU patients. With the rise of mechanical ventilation throughout the world its occurrence will only increase. Mortality from VAP is in the range of 30-70%. With early diagnosis and treatment the mortality may be decreased. In this review we will discuss the pathophysiology, diagnosis and treatment of VAP. Through proper education and diagnosis we may be able to decrease the incidence of VAP and thereby decrease the complications of this very common problem.

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Loop Diuretics in Acute Oliguric and Pre-renal States

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Oliguria is common in critically ill patients, the most common cause being a reduction of the effective intravascular volume. Oliguric patients are almost universally treated with escalating doses of loop diuretics in the hope of increasing urine output. However, in the setting of a reduced effective intravascular volume loop diuretics cause a marked fall in glomerular filtration rate with an acute decline in renal function. In this paper we demonstrate that there is no scientific rationale or clinical evidence to support the use of loop diuretics in patients with oliguria and pre-renal azotemia, prophylactically in patients at risk of developing acute renal failure and in patients with established acute renal failure.

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Henderson-Hasselbalch vs Stewart: Another Acid-Base Controversy

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The Henderson-Hasselbalch approach to acid-base physiology and disorders has been the dominant approach for the last 100 years. Over the last 20 years there has been considerable interest in a different approach developed by Peter Stewart. At the center of the controversy around the Stewart approach is replacing the role of bicarbonate with the strong-ion-difference and total weak-acid concentration.The Stewart approach, however, appears to better describe the nature and complexity of the clinical acid-base disorders of the critically ill. The old and the new maybe partially reconciled by combining Stewart’s approach with base-excess. This combination appears to have considerable clinical utility.

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Assessement of Change in Body Water By Multiple Frequency Bioelectrical Impedance in Patients Undergoing Cardiopulmonary Bypass

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Objective: To evaluate the relationship between changes in body bioelectrical impedance (BI) at 1, 50, 100 kHz and fluid balance, as an index of body water changes, in patients undergoing cardiopulmonary bypass.
Design: Descriptive, correlative.
Setting: Intensive Care Unit of a cardiac center Patients: Twenty male patients, before and after elective coronary artery bypass graft surgery with cardiopulmonary bypass.
Interventions: None.
Measurements: Whole body bioelectrical impedance using multiple frequency bioelectrical impedance (Dietosystem, Italy) at multiple frequencies (1, 50, 100 kHz) was conducted preoperatively and three times during the 24 hour postoperative period. The volume of body water compartment was calculated using Guricci’s formula. The calculated fluid balances uncorrected for insensible water losses were measured from fluid intake and output.
Findings: In 24 hours after surgery calculated total body water (TBW), extracellular water (ECW), and intracellular water (ICW) increased by 16.0%, 20.7%, and 13.0%, respectively, but the values were within desirable ranges. There was no correlation between TBW changes measured by MFBIA and calculated fluid balance.
Conclusions: The current study indicates that changes of body water compartment occur during 24 hours after CABG. Calculated ICW increases within 24 hours after CABG.

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SCCM’s Patient and Family Web site

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This Web site will link you to a variety of resources and brochures that may help you understand the ICU environment and the work that occurs there.

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Effectiveness Study of rHuEPO in the ICU

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Purpose: To evaluate the clinical outcomes and resource use in ICU patients receiving rHuEPO in a naturalistic setting.
Methods: A retrospective, case-matched (1:2 ratio) study compared patients receiving rHuEPO to a control group. Patients admitted between January 2000 and July 2002 with an ICU length of stay (LOS) ¡Ý3 days were identifi ed by an electronic data repository. Patients, who received rHuEPO prior to ICU admission, had chronic renal failure or were <18 years of age were excluded. Patients were matched by age (¡À5 years), sex, admission year and ICU type. Collected data included patient demographics, admission date, ICU and hospital mortality and LOS, mechanical ventilation days, serum creatinine concentration, hemoglobin concentration, number of blood transfusions, and ICU resource use. Results: rHuEPO-treated patients (n=391) were matched with 782 controls. Patients receiving rHuEPO had higher Simplifi ed Acute Physiology Scores II (46.2 vs 38.8; p <0.001) and received signifi cantly more blood transfusions than control patients (19 vs 6; p <0.001). After adjusting for severity of illness in a linear regression model, rHuEPO was signifi cantly associated with increased blood transfusions and higher mortality risk. Patients receiving rHuEPO had signifi cantly longer hospital and ICU LOS, mechanical ventilation duration, and higher hospital and ICU mortality rate and hospital resource use (p <0.001). Conclusions: In this real-world retrospective analysis, critically ill patients treated with rHuEPO did not experience clinical benefi ts; however, patients were sicker and received rHuEPO late in their ICU stay. Monitoring prescribing patterns and patient selection of rHuEPO treatment in critically ill patients in clinical practice is recommended to optimize rHuEPO use and outcomes.

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37th Critical Care Congress

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http://www.sccm.org/SCCM/Annual+Congress/Program/

The 37th Critical Care Congress will offer educational sessions on a wide variety of relevant and timely topics that all members of the multiprofessional team will find vital to their practice. The 2008 Congress curriculum will be packed with world-renowned speakers, interactive workshops, thought-provoking panel discussions, stimulating educational sessions, and the opportunity to earn continuing education credits.

At the conclusion of the 37th Critical Care Congress, participants should be able to:

*Recognize recent advances in drug design and development and the relevance to critical illness
*Apply patient care to current and cutting edge information regarding specific therapeutic interventions for the critically ill or injured
*Review, in the context of the intensivist-led, multiprofessional team, new knowledge and strategies to optimize the care and outcomes of the critical care patient

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