Computational study of the effect of geometric and flow parameters on the steady flow field at the rabbit aorto-celiac bifurcation.

Arterial hemodynamic forces may play a role in the localization of early atherosclerotic lesions. We have been developing numerical techniques based on overset or "Chimera" type formulations to solve the Navier-Stokes equations in complex geometries simulating arterial bifurcations. This paper presents three-dimensional steady flow computations in a model of the rabbit aorto-celiac bifurcation. The computational methods were validated by comparing the numerical results to previously-obtained flow visualization data. Once validated, the numerical algorithms were used to investigate the sensitivity of the computed flow field and resulting wall shear stress distribution to various geometric and hemodynamic parameters. The results demonstrated that a decrease in the extent of aortic taper downstream of the celiac artery induced looping fluid motion along the lateral walls of the aorta and shifted the peak wall shear stress from downstream of the celiac artery to upstream. Increasing the flow Reynolds number led to a sharp increase in spatial gradients of wall shear stress. The flow field was highly sensitive to the flow division ratio, i.e., the fraction of total flow rate that enters the celiac artery, with larger values of this ratio leading to the occurrence of flow separation along the dorsal wall of the aorta. Finally, skewness of the inlet velocity profile had a profound impact on the wall shear stress distribution near the celiac artery. While not physiological due to the assumption of steady flow, these results provide valuable insight into the fluid physics at geometries simulating arterial bifurcations.

Local hospital systems: fact or fancy?

In summation, Luke's article presents a series of concepts and tools that provide insight into local system building. Most of the material holds up well to the "reality test." Additional studies should be undertaken that include ambulatory, aging, and social services. The regional system of the future will likely include a range of services from wellness to hospice. We need to know how to bundle such services and provide them within the capitation payments. Such service offerings must be easily accessible to the consumer. We have our work cut out for us!

Renewal and change for health care executives.

Health care executives must consider renewal and change within their own lives if they are to breathe life into their own institutions. Yet numerous barriers to executive renewal exist, including time pressures, fatigue, cultural factors, and trustee attitudes. This essay discusses such barriers and suggests approaches that health care executives may consider for programming renewal into their careers. These include self-assessment for professional and personal goals, career or job change, process vs. outcome considerations, solitude, networking, lifelong education, surrounding oneself with change agents, business travel and sabbaticals, reading outside the field, physical exercise, mentoring, learning from failures, a sense of humor, spiritual reflection, and family and friends. Renewal is a continuous, lifelong process requiring constant learning. Individual executives would do well to develop a framework for renewal in their careers and organizations.

Behavior is the most effective communicator.

Actions speak louder than words. This is one of the most important strategies for successful organizational communications. Managers can best communicate their organization's vision, values, and concern for customers and employees through their own behavior.

Culture can make or break a restructuring.

Organizational restructuring doesn't always bring about anticipated change; often, that's because management doesn't put enough effort into aligning the organization's culture with the new structure. Redesign must lead trustees, clinicians, managers, and employees to behave differently from before.

Employees can be your competitive edge.

In a service organization such as a hospital ... human capital is at a premium. During a period of transformation, it is particularly crucial that top management recognize the value of their work force and the strategic importance of the human resource function in managing change.

Employee rewards can pay off for hospitals.

For many of us, a performance appraisal has all the appeal of a trip to the dentist, especially when the review isn't a positive one. Yet when performance reviews are conducted in an atmosphere of trust and open exchange, they can cement relationships, enhance commitment, and reinforce new behaviors.

Caring for the aged requires communication, trust, and appropriate services.

This special report discusses different strategies management and the board should explore to gain a better understanding of the health care needs of the elderly in their community, to establish a cooperative relationship with senior citizen groups, and to provide appropriate services for an aging population.

Corporate cultures and business strategy: a health management company perspective.

This article develops a framework of analysis for understanding corporate cultures, and applies available analytical tools to the cultural study of four health management organizations. A distillation of the relevant literature was performed to establish working definitions, tools of analysis, and various caveats. Examples of corporate cultural studies follow, and an attempt was made to identify the cultural dimensions, typology, and anticipated strategies for the four multis. The author emphasizes that healthcare companies which want sustained changes in their business lines must examine and carefully alter their firms' culture to support and reinforce such changes.