By A. Iomar. West Coast University.
Heart disease and stroke statistics–2013 update: a report from the American Heart Association cheap sildalist 120 mg free shipping. Understanding trends in inpatient surgical volume: vascular interventions best 120 mg sildalist, 1980–2000. Regulation of smooth muscle cell scavenger receptor expression in vivo by atherogenic diets and in vitro by cytokines. The myth of the “vulnerable plaque”: transitioning from a focus on individual lesions to atherosclerotic disease burden for coronary artery disease risk assessment. Prognostic value of nonobstructive and obstructive coronary artery disease detected by coronary computed tomography angiography to identify cardiovascular events. Platelet gene polymorphisms and cardiac risk assessment in vascular surgical patients. Diagnosis and management of the metabolic syndrome: an American Heart Association/National Heart, Lung, and Blood Institute Scientific Statement. Are changes in carotid intima-media thickness related to risk of nonfatal myocardial infarction? Coronary artery disease in peripheral vascular patients: a classification of 1000 coronary angiograms and results of surgical management. Concordance of preoperative clinical risk with angiographic severity of coronary artery disease in patients undergoing vascular surgery. Perioperative cardiac events in patients undergoing noncardiac surgery: a review of the magnitude of the problem, the pathophysiology of the events and methods to estimate and communicate risk. Association between postoperative troponin levels and 30-day mortality among patients undergoing noncardiac surgery. Long-term cardiac prognosis following noncardiac surgery: the Study of Perioperative Ischemia Research Group. Effect of atenolol on mortality and cardiovascular morbidity after noncardiac surgery: multicenter study of Perioperative Ischemia Research Group. The effect of bisoprolol on perioperative mortality and myocardial infarction in high-risk patients undergoing vascular surgery. Dutch Echocardiographic Cardiac Risk Evaluation Applying Stress Echocardiography Study Group. Effect of perioperative beta blockade in patients with diabetes undergoing major non-cardiac surgery: randomised placebo controlled, blinded multicentre trial. Preoperative beta-blockers do not improve cardiac outcomes after major elective vascular surgery and may be harmful. Beta-adrenergic blockers for perioperative cardiac risk reduction in people undergoing vascular surgery. Patterns of beta-blocker initiation in patients undergoing intermediate to high-risk noncardiac surgery. Perioperative beta-blockade: atenolol is associated with reduced mortality when compared to metoprolol. Premedication with oral and transdermal clonidine provides safe and efficacious postoperative sympatholysis. Effect of clonidine on cardiovascular morbidity and mortality after noncardiac surgery. Alpha-2 adrenergic agonists for the prevention of cardiac complications among patients undergoing surgery. Alpha-2 adrenergic agonists to prevent perioperative cardiovascular complications: a meta-analysis. The use of angiotensin-converting enzyme inhibitors in patients undergoing coronary artery bypass graft surgery. Preoperative angiotensin-converting enzyme inhibitors and acute kidney injury after coronary artery bypass grafting. Effects of angiotensin-converting enzyme inhibitor therapy on clinical outcome in patients undergoing coronary artery bypass grafting. Renin-angiotensin blockade is associated with increased mortality after vascular surgery. Preoperative statin therapy is associated with reduced cardiac mortality after coronary artery bypass graft surgery. The impact of postoperative discontinuation or continuation of chronic statin therapy on cardiac outcome after major vascular surgery. Reduction in cardiovascular events after vascular surgery with atorvastatin: a randomized trial. Statin use is associated with reduced all-cause mortality after endovascular abdominal aortic aneurysm repair. Withdrawal of statins increases event rates in patients with acute coronary syndromes. Perioperative statin therapy for improving outcomes during and after noncardiac vascular surgery. Meta-analysis of the effects of statins on perioperative outcomes in vascular and endovascular surgery. Low-dose aspirin for secondary cardiovascular prevention: cardiovascular risks after its perioperative withdrawal versus bleeding risks with its continuation—review and meta-analysis. Dual antiplatelet therapy prior to expedited carotid surgery reduces recurrent events prior to surgery without significantly increasing peri-operative bleeding complications. Preoperative antiplatelet and statin treatment was not associated with reduced myocardial infarction after high-risk vascular operations in the Vascular Quality Initiative. Clopidogrel is not associated with major bleeding complications during peripheral arterial surgery. Coronary plaque rupture in patients with myocardial infarction after noncardiac surgery: frequent and dangerous.
Suller and Lloyd120 observed a logarithmic reduction in bacterial cell counts in 10 to 15 hours in aerobic conditions compared with more than 60 hours to achieve the same result in an anaerobic environment for four facultative anaerobic staphylococcal strains exposed to vancomycin in air-equilibrated versus hypoxic conditions generic 120mg sildalist. Thus discount 120 mg sildalist with amex, maintaining conditions that optimize wound oxygen will also optimize the effectiveness of many commonly used antibiotics. Unfortunately, as the authors note, there is currently “no consensus as to what comprises the optimal colorectal surgical care bundle. In the meantime, the following are approaches that anesthesiologists can take with the aim of improving wound healing and resistance to infection in their patients. Preoperative Preparation Given knowledge of the physiology of wound healing, what are the best strategies for an anesthesiologist to pursue to ensure optimal healing? To the degree they are predictable, interventions can be targeted at those patients most at risk (Table 8-6). These percentages may 531 seem high, but this index was constructed on 3% of the American surgical patients from 1975–1976 and 1983, and the overall results are consistent with numerous other studies. The decision to delay surgery must take into account both the urgency of the surgery and the severity of the risk. Adverse psychosocial circumstances at the time of surgery may put patients at risk for poor wound healing. High-hostile couples produced more proinflammatory cytokines and healed more slowly than low-hostile couples. High-dysphoric individuals had higher wound sizes from day 2 onward and depressive symptoms predicted slower wound healing. Collectively, these studies point to links between psychosocial distress, dysregulation at the system level, and impaired capacity for wound healing. It seems likely that stress-reduction techniques will reduce wound complications, and well-designed clinical trials are needed in this area. Intraoperative Management 532 Careful surgical technique is fundamental to optimal wound healing (Table 8- 7). Delicate handling of the tissue, adequate hemostasis, and surgeon experience lead to healthier wounds. Incisions should be planned with regard to blood supply, particularly when operating near or in old incisions. Mechanical retractors should be released from time to time to allow perfusion to the wound edges. Because dried wounds lose perfusion, wounds should be kept moist, especially during long operations. Edema, obesity, the possibility of unacceptable respiratory compromise, or the need to debride grossly contaminated or necrotic soft tissues can all interfere with closure of the wound. All anesthetic agents tend to cause hypothermia—first, by causing vasodilation, which redistributes heat from core to periphery in previously vasoconstricted patients, and second, by increasing heat loss and decreasing heat production. The onset of pain with emergence from anesthesia adds to this vasoconstriction because of the associated catecholamine release. More recently, a number of other effective approaches have been introduced, including resistive warming, negative pressure warming, and thin, adhesive circulating water pads that are applied directly to the skin. Numerous factors, including patient comorbidities, medications such as diuretics, fever, preoperative volume state, surgical procedure, blood and insensible losses, and surgical stress all influence fluid requirements during surgery. It is widely agreed that the goal of intraoperative fluid management is to ensure sufficient intravascular volume to maintain perfusion and maximize oxygen delivery to the tissues, while avoiding the ill effects of hypervolemia, namely interstitial edema; what is difficult to determine is how to achieve that goal. Patient monitoring, fluid choice, and fluid administration strategy are topics of much debate, with a poorly standardized and often contradictory literature. For a comprehensive review of fluid management, see Chapter 16: Fluids, Electrolytes and Acid- Base Physiology. Estimating preoperative volume status can be challenging, as there are many factors to consider. Preoperative fluid state may be reduced by fasting, mechanical bowel preparation, or medication use. Pre-existing medical conditions such as systolic and diastolic heart failure may cause hypervolemia and physiology that is exquisitely sensitive to fluid overload. While hemodialysis reliably induces hypovolemia, patients with end-stage renal disease are also susceptible to fluid overload, and intraoperative fluid replacement is complex. Patient history and physical examination, for more straightforward patients, and other tools such as preoperative echocardiography, for complex patients, can give the anesthesiologist an idea of presurgical patient’s general volume status. There are known serious complications of both hyper- and hypovolemia, particularly in the perioperative period. The major complications of hypovolemia, aside from hemodynamic instability, include decreased oxygenation of surgical wounds (which predisposes to wound infection),42 63 88,130–132, , decreased collagen formation,42,103 impaired wound healing, and increased wound breakdown. The major complications associated with hypervolemia include pulmonary edema, congestive heart failure, edema of gut with prolonged ileus, and possibly an increase in cardiac arrhythmias. In addition to providing hydration, there is evidence that this is a safe practice with the additional benefits of increased patient satisfaction135 and decreased postoperative insulin resistance. Estimates of blood loss, third-space fluid losses, and maintenance requirements are notoriously inaccurate and may lead to either over- or underreplacement if used as guides. Currently, most practitioners rely on clinical acumen, vital signs such as heart rate and blood pressure, and urine output to manage perioperative fluids. Surgical patients can be markedly hypovolemic without a change in any one of these variables because of the compensatory action of peripheral vasoconstriction. Static monitors such as heart rate, blood pressure, urine output, central venous pressure,42,63,103,140 and pulmonary artery catheters have been shown to be limited. More dynamic monitors such as stroke volume assessment, pulse pressure variation, and systolic pressure variation can be predictive of fluid responsiveness141; however, these have limitations, including the requirements of a regular R to R interval, closed chest, and adequate tidal volumes. Echocardiography, including assessment of stroke volume and other indices for preload, afterload, and contractility, can be a helpful intraoperative guide,142 but large-scale clinical trials are needed to validate its use as a dynamic modality for monitoring.