Acta chirurgica Scandinavica. Supplementum最新文献

Studies suggest that epidural anesthesia has advantages over general anesthesia in patients with occlusive atherosclerotic disease undergoing vascular surgery in the lower limb. Epidural anesthesia allows maintenance of good hemodynamic stability and elicits no stress reactions. In addition, it does not compromise blood flow to the lower limb. Local anesthetic agents may exert potentially beneficial effects on the production of prostacyclin by endothelial cells, blood cell aggregation, and blood viscosity. All of these factors influence graft patency and thus the success of vascular surgery.

Three retrospective studies were conducted at St. Vincent's Hospital to compare the outcomes of colorectal anastomoses, with and without resections, with respect to anesthetic technique. Operations were performed upon patients anesthetized with either combined regional (epidural) and general anesthesia (CRAG) or general anesthesia alone (GA). Postoperative pain relief was achieved with either continuous epidural analgesia (CEA) in the CRAG group or with postoperative narcotics in the GA groups (GA/PN). In one group, a different regimen was introduced: combined epidural and general anesthesia with postoperative epidural morphine (CRAG/EDM). Overall, anastomotic leak rates and death rates were lower in the CRAG group, and the lowest incidence of anastomotic leak was reported in the patients receiving CEA. Thus the reduced leak rate was associated more with the postoperative analgesia regimen than with the anesthetic technique. An increased incidence of wound dehiscence occurred with postoperative epidural morphine analgesia.

The alteration in left and right ventricular (LV, RV) function during and immediately following coronary artery bypass surgery has been investigated in four studies, which are summarized here. In a total of 88 patients, anesthetized with morphine in oxygen (O2), basic hemodynamic monitoring and first pass radionuclide angiography were used to document changes in LV and RV function, LV compliance, and the effects of preload augmentation and afterload reduction on LV function. Two groups of patients with different physiologic responses were identified: those with preoperative ejection fractions (EF) greater than 0.50 and no dyssynergy (group I) and those with EF less than 0.50 or with dyssynergy (group II). In group I (n = 14), LV compliance was preserved following bypass (improved in four patients, no change in the remaining 10); normalized LV and RV stroke work were minimally depressed (70% of control); ejection fraction were minimally decreased (5%); and recovery of function occurred within 4 hours following bypass. In group II (n = 8), LV compliance decreased in all patients; RV and LV systolic function was moderately to severely depressed (40% of control); and recovery did not occur within 24 hours after bypass. In both groups, afterload reduction improved cardiac index, stroke volume index, and LV stroke work index after bypass, but the effects were more pronounced in group II patients. Preload augmentation with 1,500 ml of volume was not effective in either group when wedge pressure exceeded the normal ranges. Thus, significant ventricular dysfunction (RV and LV; systolic and diastolic) occurs during the immediate and prolonged post-bypass periods and can be predicted from the preoperative ejection fraction and degree of dyssynergy.

This brief review presents an update of studies on postoperative fatigue and convalescence and the way in which they are affected by anesthetic technique. Development of postoperative fatigue is related to the degree of surgical trauma, but not to general anesthesia, and it cannot be predicted from age, sex, duration of surgery, or preoperative assessment of various nutritional parameters. Postoperative fatigue correlates with deterioration in nutritional status and impaired adaptability of heart rate to orthostatic stress and bicycle exercise. Decreases in muscle performance and endurance are associated with postoperative fatigue, but psychological factors such as preoperative degree of anxiety do not appear to be important factors. Pain relief with regional anesthetics does not improve postoperative fatigue after abdominal surgery; however, no studies are available that evaluate the effects of regional analgesia with concomitant inhibition of the stress response. Controlled studies suggest that the use of regional anesthesia with local anesthetics reduces duration of hospitalization and time to ambulation. Further studies are needed to define the relative roles of immobilization, impaired nutritional intake, and surgical stress response in the pathogenesis of postoperative fatigue.

This short review updates information on the release mechanisms of the systemic response to surgical injury and the modifying effect of pain relief. Initiation of the response is primarily due to afferent nerve impulses combined with release of humoral substances (such as prostaglandins, kinins, leukotrienes, interleukin-1, and tumor necrosis factor), while amplification factors include semi-starvation, infection, and hemorrhage. The relative role of the various signals in producing the complex injury response has not been finally determined, but the neural pathway is probably most important in releasing the classical endocrine catabolic response, while humoral factors are important for the hyperthermic response, changes in coagulation and fibrinolysis immunofunction, and capillary permeability. The modifying effect of pain relief on the surgical stress response is dependent upon the technique of analgesia. However, the effect on humoral-mediated responses is small, regardless of the technique used. Afferent neural blockade with local anesthetics is the most effective technique for reducing the endocrine-metabolic response, but only in operations in the lower part of the abdomen, probably because of insufficient afferent blockade during thoracic epidural analgesia. Systemic opiate administration, as well as non-steroidal antiinflammatory drugs, exert only a small modifying effect on the response. Low-dose combined analgesic regimens may provide total pain relief, but exert no important effect on the stress response. In summary, pain alleviation itself may not necessarily lead to an important modification of the stress response, and a combined approach with inhibition of the neural and humoral release mechanisms is necessary for a pronounced inhibition or prevention of the response to surgical injury.

Infrainguinal arterial reconstruction utilizing autogenous vein grafts provides acceptable results in most cases, yet 15-25% of such grafts fail during the first 5 years. Secondary reconstruction, especially when vein graft failure is identified prior to total thrombosis, frequently restores significant patency although multiple attempts may be required. While the reasons for initial graft failure are understood in many cases, a significant number of early failures occur within 30 days without a specific cause being determined. While the in situ technique combined with completion angiography has reduced the incidence of these early failures, in order to effect further reductions, surgical and anesthetic management must address such diverse entities as vasospasm, hypercoagulopathy, embolization, and systemic hypotension.

The risk of colorectal carcinoma was estimated retrospectively in a cohort of patients with ulcerative colitis from three defined geographical areas (West Midlands and Oxford regions, England and Stockholm County, Sweden). The cohort consisted of 824 primary referral patients with a diagnosis of ulcerative colitis established within five years from onset of symptoms between 1945-1965. All patients were 15 years of age or more at onset and they were followed for a minimum of 17 years and a maximum of 38 years. There was an eight-fold risk of developing colorectal cancer in the series as a whole, relative to that of the general population. In extensive colitis the risk was nineteen-fold. The cumulative risk of developing cancer in extensive colitis was 12% after 25 years of disease duration. No significant effects of the cancer risk for age at onset, sex or referral centre were detected. Abnormal, aneuploid DNA-content of cell nuclei in colorectal mucosal biopsies was found in five out of 53 patients with longstanding, total ulcerative colitis in a prospective study using flow cytometric DNA-analyses. Findings of DNA-aneuploidy were found at repeated examinations in four of these patients and there was a correlation with precancerous, mucosal changes (dysplasia) found at histological examination. In one patient DNA-aneuploidy preceded the finding of a carcinoma (Dukes' A) in the colon. Microspectrophotometry of imprint preparations from mucosal biopsies was compared to flow cytometry for detection of nuclear DNA-aneuploidy in seven patients with ulcerative colitis in a prospective study. DNA-aneuploidy was detected in five patients in eight separate locations of the colon and rectum. There was a good conformity between the two methods in the detection of DNA-aneuploidy, which was detected in non-dysplastic mucosa as well as in association with dysplasia. In a fifteen year follow-up surveillance program, comprising 72 patients with total ulcerative colitis, colonoscopy was performed at fixed intervals and biopsies sampled from ten predetermined locations in the colon and rectum. Definite dysplasia developed in 12 patients, two of which had carcinoma (Dukes' A). Nine patients were selected for prophylactic colectomy due to findings of dysplasia. A sequential development of dysplasia was found in seven patients. The cumulative risk of developing at least low grade dysplasia was 14% after 25 years of disease duration. Using flow cytometry, DNA-aneuploidy was detected in 12 out of 59 patients, significantly correlating with low and high grade dysplasia.(ABSTRACT TRUNCATED AT 400 WORDS)