Clinics in Anaesthesiology最新文献

Evaluation of the geriatric patient for orthopedic operations is similar to patient evaluation for any other procedure. Concomitant diseases must be diagnosed and treated to bring the patient to an optimal physical status. The evaluation can only be thorough when the anesthesiologist has a good understanding of indications for the procedure, the pathophysiology involved and knowledge about the operative procedure.

Communication at all levels of the medical care system must continue to be developed to maintain a high level of patient care in face of increasing pressures from various cost containment programs. Premedication must be individualized and big doses require surveillance.

Orthopedic operations performed in geriatric patients frequently lend themselves to regional anesthesia but anesthesiologists' skill may be a limitation. It continues to be controversial whether regional anesthesia reduces morbidity and mortality over general anesthesia. General anesthesia is indicated if this is the technique with which the anesthesiologist is most familiar and if it is what the informed patient requests.

Outpatient surgery can be performed safely in elderly patients at a great saving in cost and increase in convenience. It need not be limited to Physical Status I and II patients. Special techniques are useful which take into account the changes in metabolism, drug uptake and elimination which occur in the elderly. Drug dosage must be adjusted. Local and field block anesthesia has proved to be very useful. Facilities must be at hand for hospital admission when necessary.

Sympathetic and efficient registration personnel are essential, so that patients are informed and calm. Recovery room staff who are skilled in evaluating pain and in treating nausea reduce the admission rate to a low level.

Hypertension in the elderly patient presents a unique challenge for the anesthesiologist, a challenge that will be seen with increasing frequency. In addition to pathophysiologic alterations which occur secondary to hypertension, changes which normally occur with aging can interact with hypertensive pathology and must be evaluated to provide optimal anesthesia.

Vascular surgery has progressed to a point where the elderly patient is commonly a candidate for a variety of surgical procedures. Anesthetic management of these high-risk patients must be directed towards support of the various systems involved in this diffuse process. Of primary concern is the cardiovascular system which accounts for a significant early postoperative mortality. Evaluation of the degree of coronary artery disease in conjunction with the cardiologist allows appropriate preoperative decision to be made including initial revascularization of the coronaries as well as the operative monitoring needs. The pulmonary, renal and central nervous systems are also at risk and must be supported. The use of invasive cardiovascular monitoring and a variety of vasoactive drugs have permitted the care of these patients to be carried out in a very physiologic manner. Surgeons and anesthetists working in close communication and understanding each other's problems have given elderly high-risk patients many more useful years.

The aged are at great risk for developing perioperative hypoxemia due to age-induced ventilation/perfusion abnormalities, underlying lung disease, the impact of anesthesia and surgery on FRC, or a combination of these and other factors. The physiologic basis of these various processes in the elderly has been presented along with suggestions for anesthetic management and postoperative care. When any intervention is planned, the frailty of these individuals should be recalled.

The above material is presented in an effort to give the clinician the basic knowledge necessary to care for the elderly patient with heart disease. It is important to remember that the anesthetic technique is not meant to cure the patient. Often it is optimal to leave the patient at hemodynamic baseline, if they are stable, rather than try to manipulate the patient's hemodynamic profile to a more acceptable value. This maneuver may often result in hemodynamic deterioration of the patient. Additionally, other concerns may face the anesthesiologist when multiple valvular lesions, coronary artery stenoses and/or myocardial dysfunction all exist within the same patient. In this case, one must determine the predominant lesion, if any, which deserves primary attention. The pros and cons of each anesthetic intervention must be weighed and the response to each closely monitored. There are no magic formulas to guide management of these problems; rather, there are a constellation of tools which the clinician may utilize in order to provide optimal care.

Diabetes mellitus is frequently encountered in elderly patients who enter the hospital for surgery. The overwhelming majority of these patients have NIDDM. The diagnosis of NIDDM in elderly patients is difficult because the metabolism of a glucose load is progressively impaired during aging. The mechanism for this alteration is not completely clear, but insulin antagonism appears to be a major factor. The criteria recommended by the National Diabetes Data Group are useful in establishing the diagnosis.

The pathogenic influences in NIDDM include insulin deficiency, insulin resistance and accelerated hepatic glucose production. The pathogenesis of IDDM involves genetic, immunologic and viral etiologies.

The concerns of the anesthesiologist in caring for elderly patients with diabetes relate to the acute and chronic complications of the disease. Acute complications consist of diabetic ketoacidosis, hyperosmolar non-ketotic syndrome, lactic acidosis, hypoglycemia, infection and delayed wound healing. Chronic complications include retinopathy, nephropathy, neuropathy, cardiovascular disease and dermatologic abnormalities.

A thorough preoperative evaluation with correction of organ dysfunction and metabolic derangement to the extent possible is essential to the safe conduct of anesthesia. The choice of anesthetic technique is dependent upon many factors, but regional anesthesia, when feasible, is the preferred technique for the elderly diabetic. Regardless of the anesthetic technique selected, it is essential to carefully monitor and control blood glucose during the perioperative period in order to avoid the adverse effects of uncontrolled hyperglycemia or hypoglycemia.

The structural and functional changes which aging imposes upon the nervous system are extensive, reasonably well documented, and must be considered as significant factors which reduce the pharmacodynamic aspects of anesthetic requirement in elderly patients. However, changes in pharmacokinetics play the most important role in producing residual nervous system depression and prolonged unconsciousness in elderly patients in the immediate postoperative period. The high prevalence of cerebrovascular disease in the elderly surgical population makes it inevitable that catastrophic events such as cerebrovascular accident and embolization will contribute in a small but important manner to postoperative nervous system morbidity and mortality. The frequency with which elderly patients have multiple organ system disorders also makes them at high risk of metabolic and homeostatic disruption, frequently manifest as nervous system symptomatology.

Sensitive tests of the more complex aspects of nervous system function of elderly patients such as affect, abstraction, memory and logic reveal a disturbing phenomenon: one-quarter to one-third of these individuals develop new and persistent dysfunction in the immediate or long-term periods of recovery from anesthesia. It is currently impossible to determine the relative magnitude of the contributions made by illness, the hospital environment, surgical stress or the residual effects of anesthetic drugs. Although increasingly favorable figures for gross mortality suggest that, in modern practice, age per se is no longer considered to be an absolute contraindication to general anesthesia as far as survival is concerned, there must be greater awareness that many subtle and intricate aspects of cognitive and affective mental function in these patients may be compromised even under the best of circumstances. Although permanent nervous system damage from routine general anesthesia is extremely rare, many elderly surgical patients require weeks or months to achieve full spontaneous recovery of their preoperative mental status, for reasons that are still unknown. At this stage in our understanding, one can expect a properly conducted general anesthetic to produce uneventful emergence from anesthesia and eventual full recovery of preoperative mental function if the surgical procedure contributes materially to the physical and psychological wellbeing or to the social integration of the elderly surgical patient.