Deconstructing the myth of the advanced practice blended role: support for role divergence

Since the early 1980s, there has been discussion about combining the clinical nurse specialist (CNS) and nurse practitioner (NP) roles. Examination of recent nursing literature reveals renewed interest in differentiating, rather than combining, these 2 advanced practice roles. Research has shown that although the 2 roles share similarities, these advanced practice pursuits are more different than alike, both philosophically and practically. Despite curricular attempts at "blending" CNS and NP philosophies of nursing care and their distinctive domains of practice in master's level degree programs, the uniqueness of these roles in actual practice demands a continuation of educational differentiation in preparation. Both roles are important and address varied systems requirements. Each role has been shaped by population needs, education, market, and legal forces that transform with time. The differing ideologies of CNS and NP practice lead to diverse patient and system outcomes and reveal different researchable questions.     

Dominant role of the kidneys and accessory role of whole-body autoregulation in the pathogenesis of hypertension

In this paper I have presented two closely related themes both of which seem to be fundamental in understanding the pathophysiology of hypertension. The first theme is the dominant role of the volume-excretion function of the kidneys in setting the long-term arterial pressure level. That is, each person in general has a rather steady intake of salt, water, and those other constituents that make up extracellular fluid. When the arterial pressure is normal, the kidney excretion of these constituents is exactly the correct amount to balance the intake of each of them. When the pressure is too great, there is more loss than gain, and the body fluid volume decreases; therefore, the pressure falls until the exact balance point is reached again; it is only at this balance point that the loss and gain are equal. At any pressure below the balance point, volume gain is greater than loss, and the pressure will continue to rise until the exact balance level is again reached. This capability of the kidney mechanism to return the pressure all-the-way back to the level of balance between input and output--not merely part-way back--is called the "infinite gain" characteristic of this pressure control system, and the level to which the pressure is controlled is called the "set-point" of the system. In pathophysiological states, the set-point for pressure control can be increased to hypertensive levels as a result of (1) a pathophysiological change in renal function or (2) increased salt and volume intake; then hypertension will ensue. Other abnormalities of circulatory function that do not affect one of these two factors cannot cause chronic hypertension because of the infinite gain feature of the renal-volume mechanism for pressure control. One such condition that does not cause hypertension without some concurrent abnormality that affects renal function is a primary increase in total peripheral resistance. The second theme is that whole-body autoregulation causes the blood flow in all parts of the body to return or remain near to normal when high arterial pressure tries to increase the flow. It does this by increasing the resistance in all parts of the peripheral arterial tree. Therefore, in effect, autoregulation converts any tendency to high cardiac output hypertension into high resistance hypertension. Yet, in so far as is now known, the pressure level will be the same with or without autoregulation.(ABSTRACT TRUNCATED AT 400 WORDS)     

Exaggerating the role of private treatment

Abstract. Curson's analysis of the growth of private for profit treatment of substance abuse is seen as exaggerated. The main growth in the 1980s was over 50% in the voluntary charitable sector. His criticism of lay' counsellors ignores the responsibility of health care professionals, to train and supervise them. Curson's criticism of the effectiveness of treatment in general indicates he is not well informed and his reference to Minnesota Model outcome research and the philosophy of the mutual help movement of AA is misleading.     

role of the normal gut microbiota

Relation between the gut microbiota and human health is being increasingly recognised. It is now well established that a healthy gut flora is largely responsible for overall health of the host. The normal human gut microbiota comprises of two major phyla, namely Bacteroidetes and Firmicutes. Though the gut microbiota in an infant appears haphazard, it starts resembling the adult flora by the age of 3 years. Nevertheless, there exist temporal and spatial variations in the microbial distribution from esophagus to the rectum all along the individual's life span. Developments in genome sequencing technologies and bioinformatics have now enabled scientists to study these microorganisms and their function and microbehost interactions in an elaborate manner both in health and disease. The normal gut microbiota imparts specific function in host nutrient metabolism, xenobiotic and drug metabolism, maintenance of structural integrity of the gut mucosal barrier, immunomodulation, and protection against pathogens. Several factors play a role in shaping the normal gut microbiota. They include(1) the mode of delivery(vaginal or caesarean);(2) diet during infancy(breast milk or formula feeds) and adulthood(vegan based or meat based); and(3) use of antibiotics or antibiotic like molecules that are derived from the environment or the gut commensal community. A major concern of antibiotic use is the long-term alteration of the normal healthy gut microbiota and horizontal transfer of resistance genes that could result in reservoir of organisms with a multidrug resistant gene pool.     

Ventricular diastole and the role of the pericardium

In order to understand the mechanics of left ventricular (LV) diastolic filling it has become important to understand the role of the pericardium. This is because it has been demonstrated that the LV pressure-volume relationship can be shifted by previously unrecognized changes in pericardial "pressure" and, therefore, LV end-diastolic pressure (LVEDP) may be ambiguous as a measure of preload. The key to this understanding is to appreciate that (except in the case of pericardial effusion or tamponade) the pericardium impedes cardiac filling by exerting a stress, not by raising the pressure in the pericardial fluid, and that the magnitude of this stress is variable and relatively great. When animals or humans are volume loaded acutely, this stress is approximately equal to right ventricular (RV) filling pressure. Thus, while it may not be possible to estimate true preload from simple measurements of LVEDP, subtracting RV filling pressure from LVEDP may provide a useful estimate of transmural LVEDP. As an example of the effect of the pericardium, recent laboratory results indicated that the decrease in stroke volume which resulted from acute pulmonary embolization could be explained by reductions in LV preload. Transmural LVEDP and end-diastolic volume decreased in spite of the fact that LVEDP rose markedly. Since LVEDP increased while stroke volume decreased, it might have been concluded that contractility had decreased. However, this was shown not to be the case, since the reduction in stroke volume only corresponded to the reductions in transmural LVEDP and end-diastolic volume. Thus, appropriately accounting for pericardial constraint may allow many changes in LV systolic performance, hitherto thought to represent changes in contractility, to be explained on the basis of preload changes and the Frank-Starling mechanism.     

Global revascularization: the role of the cardiologist

There are compelling reasons for cardiologists to undertake a more global approach to patients with peripheral vascular diseases: atherosclerosis is a 'systemic' disease frequently causing both coronary and peripheral vascular problems in the same patient; coronary artery disease is the most common cause of morbidity and mortality in patients with peripheral vascular disease; and peripheral vascular disease negatively impacts the management of angina pectoris and congestive heart failure. There are four major areas of special interest to the cardiologist: (1) iliac arteries (vascular access), (2) renal arteries (hypertension and volume overload), (3) subclavian arteries (coronary steal with a left internal mammary artery [LIMA] graft), and (4) carotid arteries (stroke). coronary angioplasty are transferable to the peripheral vasculature. However, an understanding of the natural history of peripheral disease, patient and lesion selection criteria, and knowledge of other treatment alternatives are essential to performing these procedures safely and effectively. Appropriate preparation and training, and a team approach, including an experienced vascular surgeon, are both desirable and necessary before interventional cardiologists who are inexperienced in the treatment of peripheral vascular disease attempt percutaneous peripheral angioplasty. There are inherent advantages for patients when the cardiologist performing the procedure is also a clinician. Judgments regarding the indications, timing, and risk/benefit ratio of procedures are enhanced by a long-term relationship between physician and patient. Finally, in view of the increased incidence of coronary artery disease in patients with atherosclerotic peripheral Technical skills necessary to perform vascular disease, the participation of a cardiologist in their care seems appropriate. (Int J Cardiovasc Intervent 2000; 3: 71 79)