New horizons (Baltimore, Md.)最新文献

This issue of New Horizons is about change. While our traditional apprenticeship model of physician training has served us well, adaptation is required for the new millennium. Among several sectoral trends in medicine, two are particularly relevant for intensivists: a) the information explosion and b) increased accountability to society regarding effective, efficient, compassionate, and culturally sensitive care. Evidence-based medicine (EBM) (or any other single initiative, for that matter) is not going to address all of tomorrow's challenges. However, EBM does help by enhancing clinical informatics and critical appraisal skills so that clinicians are better able to keep up with the growing literature, and decide whether, and if so, this literature applies to individual patients. In addition, EBM can help to highlight the determinants of clinical decisions, which may include contributions of caregiver knowledge, patient pathophysiology, research evidence, patient and societal values, and increasingly, costs. While EBM is best practiced at the individual level, its application to other aspects of health care is growing.

Current recommendations about the care of dying patients advise that healthcare professionals understand and respect the goals, priorities, needs, and suffering of each dying patient and have command of the skills and resources required to address these concerns. Studies of important features of terminal illness, current use and outcome of intensive care for the terminally ill, and interventions designed to improve the outcome of care for patients who die in ICUs are reviewed to examine discrepancies between recommendations and the reality of ICU care for dying patients. Evidence indicates that it is difficult to predict the time of death or determine patient preferences about treatment prior to death. The utilization of intensive care prior to death varies widely across the United States and is a function of available resources more than individual patient need or choice. The pattern of withdrawal of life-sustaining treatment also varies widely and does not seem to follow guidelines. Families of deceased patients report that care could be improved by increased attention to analgesia and communication. The largest interventional study, the Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatment (SUPPORT), which provided physicians with information about patient prognosis and preferences for care, did not alter outcomes of end-of-life care. Smaller but successful interventional studies have included examination of an alternative team that provides care tailored to the needs of dying patients, a service tailored to promote family contact with the dying patient, and proactive consultation to facilitate care planning and communication with families. Research suggests that clinicians should be cognizant of the difficulty of predicting death and anticipate the need to change the goals of care as therapeutic trials fail; anticipate and treat bothersome symptoms of dying patients; recognize that family support and contact between the dying patient and family facilitate decision-making and acceptance of death; and facilitate the coordination of care and the development of alternative care teams in order to optimize end-of-life care.

Adapting practices that are described in the literature or used effectively in other critical care units provides an opportunity to improve the quality of critical care and reduce costs. Described in the literature are different techniques for the gradual withdrawal of mechanical ventilator support from patients during weaning from the ventilator. Phoebe Putney Memorial Hospital in Albany, GA used a systematic approach to adapt these techniques to improve the weaning process. This resulted in a reduction in the number of days patients were on a ventilator and a reduction in the ICU length of stay for patients with acute respiratory failure requiring mechanical ventilation.

Patients in an ICU are at increased risk for a nosocomial infection. Infection control practices to reduce these risks have often been based on scant information. A recent trend to base infection control practices on actual patient outcome data has often provided surprising results. Basic measures such as good handwashing and appropriate patient isolation must be followed. Routine venous catheter placement does not increase the risk of bacteremia, and increases procedure morbidity. The role of different catheter dressings and antibiotic-impregnated catheters in reducing bacteremia is unclear. Nosocomial pneumonias and ventilator-associated pneumonia are common in the ICU. Outcome studies suggest that infrequent changes of ventilatory circuits do not increase the risk of ventilator-associated pneumonia, while allowing substantial cost savings. Manipulation of the pH or flora of the gastrointestinal tract seems to have little influence on patient outcomes, even if there may be a slight reduction in nosocomial pneumonias. Although large randomized trials may be outside the scope of hospital infection control programs and ICUs, any hospital should be able to implement outcomes-based studies of changes in infection control policies and procedures.

The purpose of developing protocols and guidelines is greater than reducing variation in practice. The process also creates new paradigms and changes the culture in which health care is delivered. The protocol itself is designed to be transient. The new environment and perceptions of how to improve health care in the future, along with new relationships and processes to accomplish this, are the real power of learning to develop and implement protocols and guidelines. Framing the process of protocol development, therefore, is more important than the resulting document. In developing protocols, attention to changing the thinking and practice of the front-line practitioners, establishing new relationships, and devising new methods of delivering and improving care is key. The process of developing protocols should include all practitioners. They should remain in control of patient care using new methods that allow: a) the monitoring of process and outcomes, b) identification of problems, and c) the evaluation and validation of the effectiveness of implemented change. Evidence from the literature of strategies for protocol development and implementation which are effective in creating change are reviewed, and an example of a known effective method which improves practice is given.

The prognostic features and outcomes associated with aneurysmal subarachnoid hemorrhage (SAH) are reviewed. In the first section, the epidemiology of SAH is discussed with emphasis on prevalence, incidence, risk factors, heredity, activity, and seasonal variability. In the second section, the presentation, diagnosis, and treatment of patients with aneurysmal SAH is briefly reviewed. In the third section, the prognostic features associated with aneurysmal SAH are discussed with emphasis on neurologic condition and SAH grading scales, patient's age, aneurysm size and location, repeat hemorrhage, vasospasm, systemic disease, hypertensive response, computed tomograph features, hydrocephalus, timing of surgery, and expertise of the aneurysm center. Also in the third section, the prognostic features associated with unruptured aneurysms are discussed with emphasis on the actuarial risk of rupture, aneurysm size and location, and multiplicity of lesions. In the fourth and final section, the outcomes of aneurysmal SAH over the past 60 yrs are reviewed.

Frequent or continuous monitoring of crucial variables in patients with cerebrovascular disease allows the intensive care team to identify progression of the pathophysiologic mechanisms involved, intervene to halt or reverse this progression, and identify the response to treatment in order to modify the intervention if necessary. Central nervous system physiologic monitoring modalities include: a) the clinically-apparent function, b) physical and mechanical variables, c) circulation or perfusion, d) bioelectrical measures, and e) biochemical measures. The neurologic examination of the critically ill patient is an indispensable monitoring tool in the ICU. Patterns of neurologic signs and the trend of the examination, whether worsening or improving, are the most important factors to follow because there is no single sign or symptom which forecasts impending disaster. Intracranial pressure monitoring is applicable to all subsets of cerebrovascular disease, providing information about cerebral perfusion pressure and risk of secondary cerebral injury. Cerebral blood flow is not easily quantified in the ICU, but transcranial Doppler sonography is a reliable bedside technique that can be used for intermittent or continuous monitoring. Neurophysiologic monitoring with electroencephalography (EEG) and evoked potential (EP) testing can be used as a supplement to the neurologic exam and other diagnostic studies. EEG and EP can provide an early indication of clinically relevant change due to evolving disease or in response to therapy, which is especially helpful when the neurologic examination is limited due to severe coma, therapeutic barbiturate coma, or neuromuscular blockade. Neurometabolic monitoring in cerebrovascular disease with microdialysis is a promising technique that may be able to identify markers of cellular energy state or excitotoxicity in carefully selected areas of the brain.

Ischemic stroke in the anterior or carotid artery territory is the most common type of stroke, with a wide range of clinical manifestations. Specific stroke syndromes reflect the vascular territories involved and range from small, lacunar infarcts to those that involve the entire middle cerebral artery territory. Diagnostic imaging with computed tomography or magnetic resonance imaging is very useful for confirming the location and extent of anterior circulation strokes. Important advances for the acute management of these patients have occurred recently and more should be forthcoming soon.

Stroke is a leading cause of death and disability, particularly in the elderly population. The evolution of stroke prevention and treatment has reached a new stage whereby rapid evaluation and intervention can prevent stroke occurrence and its consequences. A stroke system much like a trauma system can be useful in getting patients to recognize signs and symptoms of stroke, mobilizing the emergency medical system (EMS), conducting diagnostic studies promptly, treating patients in a timely manner consistent with their disease process, stopping progression through monitoring and treatment, and beginning rehabilitation as early as feasible. The neurointensive care unit (neuro-ICU) is a key component of the system. It provides the monitoring and treatment for progressing stroke and its complications. Patients who might be suitable for neurointensive care are those with severe strokes, those receiving thrombolytic therapy, those receiving hypervolemia-hypertensive-hemodilution therapy, those at risk for intracranial and medical complications, and inhospital strokes following medical and surgical procedures. In order for patients to reach the neuro-ICU, education of patients, EMS providers, physicians, and hospital administrators with regard to the need for rapid response and intensive care is needed. The saga of myocardial infarction reaction is an example of the way a system of response can be developed. The concept of brain attack should alert the community and the healthcare providers of the urgency of stroke care and the need for a stroke system with neurointensive care as the therapeutic key.

In recent years there have been formidable advances in the war against stroke. The understanding and detection of stroke have undergone major progress at a rate previously unseen, partly due to major contributions from neuroradiology. Current routine neuroradiologic evaluation of acute stroke relies mainly on computed tomography scanning, although a number of radiologic modalities are becoming available that are based on various physical and chemical tissue properties, such as magnetic resonance imaging, single photon emission computed tomography, positron emission tomography, and magnetic resonance spectroscopy. All these new techniques allow the study of nervous tissue at the cellular and biochemical levels. A review of current diagnostic techniques for stroke follows in the first part of this article. The current status of endovascular therapy for ischemic stroke is reviewed in the second part of this article.