Essay Instructions: Cardiac surgery, with or without cardiopulmonary bypass [CPB], elicits a potent stress response. This stress response has two key components, activation of the inflammatory response and the release of stress hormones, including Epinephrine, norepinephrine, cortisol, and adrenocortical hormone. Nonspecific activators of the stress response include surgical trauma, blood loss and/or transfusion, and hypothermia. CPB may directly activate the inflammatory response via at least three distinct mechanisms. One mechanism involves direct 'contact activation' of the immune system following exposure of blood to the foreign surfaces of the CPB circuit. A second mechanism involves ischemia-reperfusion injury to vital organs as a result of aortic cross clamping. Restoration of perfusion on release of the aortic cross clamp is associated with activation of key indices of the inflammatory response. In addition, systemic endotoxemia, resulting from gut translocation of endotoxin across a damaged mucosal barrier compromised following splanchnic hypoperfusion, may indirectly activate the inflammatory cascade.
The inflammatory component of the stress response to cardiac surgery is increasingly well characterized. Scientific knowledge in this field is continually expanding and this area constitutes a major interface of clinical and basic scientific research. Inflammation constitutes generalized, non-specific response to tissue injury, of whatever etiology, and is a rapid, highly amplified, controlled humoral and cellular response. There are several key components of the inflammatory response to cardiac surgery. The complement cascade is activated upon contact of the blood with the foreign surfaces of extracorporeal circuit, reperfusion of ischemic tissues, and heparin neutralization with protamine. Proinflammatory cytokines such as tumor necrosis factor-a [TNFa], Interleukin-1b [IL-1b], IL-6 and IL-8 play a pivotal role in stimulating and coordinating the inflammatory process. The role of the coagulation/fibrinolytic cascades and its interaction with the inflammatory response is increasingly recognized. The cellular immune response, in particular the process of neutrophil-endothelial adhesion, may lead to widespread endothelial damage and dysfunction. The inflammatory response may result in widespread endothelial activation and diffuse endothelial injury, which is considered a key event leading widespread organ injury and dysfunction.
First, the degree of activation of the components of the complement cascade have been demonstrated to correlate with indices of pulmonary (1), renal (2), and hemostatic (2) dysfunction, and the incidence of postoperative arrhythmia (3,4) following CABG. Strategies which reduce indices of complement activation, such as improvements in CPB circuit biocompatibility (5,6), or specific anti-complement strategies (7) reduce the morbidity in patients undergoing cardiac surgery. Second, systemic spillover of pro-inflammatory cytokines, such as TNFa, IL-1b and IL-6 appear to contribute to the pathogenesis of post-CPB myocardial stunning, ischemia and dysfunction (8,9). TNFa released during CPB may contribute to the pathogenesis of postoperative hepatic (10) and renal (11) dysfunction. Strategies to remove pro-inflammatory mediators, such as mechanical removal of cytokines by hemofiltration, limit these adverse effects (12).
REFERENCES: use Journal of cardiovascular cardiothoracic surgery, Anesthesia Analgesia, British Journal of Anaesthesia, Anesthesiology, Perfusion, Critical Care Medicine.
I also am requesting that copies of the references be sent to me as well.
Also here is grading criteria:
Criteria for Grading a Scholarly Manuscript
1. Issue relevance to contemporary practice. (10%)
2. Title Page (10%)
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- Running head and page header consistent with APA limitations
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3. Abstract (10%)
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- Includes purpose, methods, scope, summarized results, and conclusions
- Approximately 150 words
4. Introduction (10%)
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5. Adequacy of literature and referencing (30%)
- Pro (advantages) and con (disadvantages) arguments presented with statistical evidence supporting the researchers conclusions
- A minimum of 5 literature sources cited supporting each pro/con argument
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- Potential effect on general practice stated
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