Acta chirurgica Scandinavica. Supplementum最新文献

Cardiovascular complications of surgery--myocardial infarction (MI), chest pain, stroke, heart failure, and rhythm disturbances--are a major cause of post-operative a major cause of post-operative morbidity and mortality. Numerous studies have been conducted on postoperative MI in diverse populations, including patients with previous MI and others with coronary artery disease (CAD) who have or have not undergone coronary artery bypass graft (CABG) surgery. This review presents data from a number of these studies, which attempted to identify predictive tools and contributing factors to postoperative MI and other ischemic events. These potentially predictive methods and factors include previous MI, hemodynamic aberrations and monitoring, drug regimens, presence of CAD, CABG surgery, preoperative and intraoperative ischemia, congestive heart failure, thallium scintigraphy, and anesthesia.

General anesthesia itself may influence postoperative lung function. It leads to a depression of the functional residual capacity, which, in combination with surgical trauma and postoperative pain, can provoke insufficient breathing, retention of bronchial secretions, and atelectasis. Regional anesthesia has no influence on lung function. After upper abdominal or thoracic surgery, postoperative epidural analgesia causes a significant increase of lung function as compared with systemic analgesia. The combination of regional anesthesia and general anesthesia intraoperatively appears to reduce lung function much less than general anesthesia alone.

Three factors that influence homeostasis are discussed: fluids and electrolytes, energy and nutrition, and immune response mediators. Cell injury induces changes in the sodium-potassium pump that disrupt fluid and electrolyte homeostasis, and surgery causes changes in functional extracellular fluid. Caloric requirements increase in proportion to the severity of the injury, and are generally greater than expected. Both parenteral and enteric feeding restore alanine and glutamine levels toward normal. Studies suggest that some of the adverse effects of surgery on homeostasis may be alleviated by specific treatments. A major key in modulating the stress response to surgery may lie in controlling immune response mediators, in particular cachectin, which has been shown to cause effects identical to those of septic shock. Recent studies have indicated that injections of small doses of specific monoclonal antibody to cachectin can avert all of the mediator's adverse effects.

In recent years hospitals have begun to institute special postoperative pain services staffed by anesthesia department personnel. The charter for such services is to provide the best and most appropriate postoperative analgesia for surgical patients, in particular for the increasing numbers of patients who, released from hospital soon after surgery, still require pain relief on an outpatient basis. This review focuses on the relative benefits and risks of the currently available options for postoperative pain relief: intramuscular (i.m.) and intravenous (i.v.) administration of narcotics; epidural or subarachnoid administration of narcotics and/or local anesthetics; and peripheral nerve blocks with local anesthetics. In terms of efficacy, cost, risk, and personnel requirements, the particular advantages of continuous analgesia techniques--including patient-controlled analgesia--are discussed.

Anesthesia can have various effects on the outcome of surgery, especially gastrointestinal procedures. Many anesthetic agents, for example, produce a fall in lower esophageal sphincter pressure, which can allow reflux of gastric contents into the lower esophagus. This can lead to potentially fatal aspiration of vomit. Anesthesia also alters gastrointestinal motility, secretion, and absorption; postoperative opiate analgesia in particular contributes to delayed gastric emptying. Anesthetic technique can affect the success of intestinal anastomosis; for example, intravenous induction agents and some inhalational anesthetics decrease regional blood flow, whereas regional anesthetics may act to increase colonic blood flow. Other aspects of anesthetic management are also discussed as they relate to surgical outcome; examples are the use of invasive monitoring in elderly patients, the importance of oxygen delivery to the anastomosis, and the effect of transfusion on survival after surgery for carcinoma.

Homologous, or banked, blood is chronically in short supply. In addition, it is associated with a number of significant risks, including transfusion-related infection with hepatitis and acquired immune deficiency syndrome (AIDS), transfusion reactions, and alloimmunization. Therefore, the benefits of reducing the dependence on banked blood are clear. Several techniques are being used to transfuse the patient's own blood during surgery. With the predeposit technique, a patient anticipating surgery donates blood during the month preceding operation. During or immediately following surgery, the patient's blood can be collected and reintroduced (whole blood salvage and reinfusion) or it can be collected, washed, and reinfused in the form of packed cells. Expanded use of these techniques and efforts to reduce blood loss during surgery can reduce the incidence of transfusion-related complications. In the future, synthetic blood substitutes may further reduce the need for homologous transfusions in surgical patients.

Various patient-, surgery-, an anesthesia-related factors probably influence the outcome of surgical procedures. The American Society of Anesthesiologists (ASA) Physical Status Classification System, while a systematic approach to the assessment of anesthetic risk factors, considers only physical status factors and lacks predictive value for individual cases. Other risk-predictive factors such as age and sex of the patient and the type, site, and duration of surgery should also be included. Multifactorial approaches include both patient- and surgery-related variables, and therefore make an individualized risk prediction possible. Although the choice of anesthetic agent does not appear to influence the incidence of complications or operative outcome, anesthetic technique and anesthesiologist skill are factors of some importance.