Circulation
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Comparative Study
Ultrasound-assisted cannulation of the internal jugular vein. A prospective comparison to the external landmark-guided technique.
Central venous access is an essential part of patient management in many clinical settings and is usually achieved with a blinded, external landmark-guided technique. The purpose of this study is to evaluate whether an ultrasound technique can improve on the traditional method. ⋯ Ultrasound-guided cannulation of the internal jugular vein significantly improves success rate, decreases access time, and reduces complication rate. These results suggest that this technique may be preferred in complicated cases or when access problems are anticipated.
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The purpose of this study was to determine the predictive value of dobutamine stress echocardiography for perioperative cardiac events in patients scheduled for elective major noncardiac vascular surgery. ⋯ Dobutamine stress echocardiography is a feasible, safe, and useful method for identifying patients at high or low risk of perioperative cardiac events. The test yields additional information, beyond that provided by clinical variables, in patients who are scheduled for major noncardiac vascular surgery.
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The identification of the components of the renin-angiotensin system (RAS) in various extrarenal tissues suggested the existence of local renin-angiotensin systems with organ-specific functions that may act independently from the plasma RAS. These findings have led to the hypothesis of paracrine-autocrine functions of the RAS, which implies that locally generated angiotensin II mediates effects within one tissue or within one cell. Whereas the circulating endocrine RAS appears to be responsible for acute effects, the tissue RAS seems to participate in more chronic processes such as secondary structural changes and therefore may contribute to the pathogenesis of hypertension as well as other cardiovascular disorders such as cardiac hypertrophy, coronary artery disease, and atherosclerosis. ⋯ The therapeutic importance of inhibitors of the RAS, such as converting enzyme inhibitors, is based on their cardioprotective as well as antiproliferative effects and points to a direct involvement of the RAS in the development and preservation of primary hypertension, a pathological condition in which normal or even low plasma renin activity is a common finding. Reversal of cardiovascular structural changes and enhancement of renal sodium excretion by converting enzyme inhibitors are important long-term antihypertensive actions possibly mediated by inhibition of the tissue RAS.
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Thrombolysis has become the standard therapeutic approach in patients with acute myocardial infarction. To identify patients who may benefit from early invasive procedures, reliable noninvasive assessment of success or failure of thrombolytic therapy is mandatory. ⋯ With regard to noninvasive prediction of coronary artery patency after thrombolytic therapy, measurement of the early initial slopes of the serum markers within only 90 minutes after the initiation of therapy is as accurate as the determination of the time to their peak concentration. Compared with the other markers examined, myoglobin appears to have advantages because of its earlier rise, yielding a better negative predictive value and a higher area under the ROC curve for determination of its early initial slopes.
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Aortic dissection still has a poor prognosis despite progress in therapy. Therefore, this prospective follow-up study was designed to determine whether the degree of communication between true and false lumen in relation to the type of dissection, analyzed by transesophageal echocardiography, influences the risk after initiation of medical or surgical therapy. ⋯ Preoperative mortality appears to be reduced by transesophageal echocardiography, allowing rapid initiation of treatment. Intraoperative and postoperative mortality in aortic dissection remains high. Risk factors are fluid extravasation and an open false lumen with high communication. Thrombus formation in the false lumen can be regarded as a good prognostic sign. Surgery appears to be only a first step in the treatment of aortic dissection. Second surgery or closure of entry sites based on intraoperative echocardiography may be considered to induce thrombus formation and reduce aortic wall stress.