Effects of intestinal ischemia-reperfusion on major conduit arteries.

Intestinal ischemia-reperfusion (I-R) is a common and serious clinical condition associated with simultaneous remote organ dysfunction. The purpose of this study was to investigate the effects of intestinal I-R on the vasomotor functions of major conduit arteries. Anesthetized rabbits were randomly assigned to one of three groups: sham-operated controls (Group I), and one-hour intestinal ischemia with two-hour reperfusion (Group II) or four-hour reperfusion (Group III). The following mechanisms of vasomotor functions were studied in abdominal aorta, superior mesenteric, renal, pulmonary, and carotid arterial rings: (1) endothelial-dependent vasodilation response to acetylcholine, (2) endothelial-independent vasodilation response to nitroprusside, (3) beta-adrenergic vasodilation response to isoproterenol, and (4) phenylephrine-induced vasoconstriction. Intestinal injury was quantified using malondialdehyde (MDA) concentration and wet-to-dry intestine weight ratio. Intestinal I-R did not affect the maximal responsiveness or the sensitivity to acetylcholine, nitroprusside, and isoproterenol in all the vessels studied. The maximal contractile response to phenylephrine increased significantly in mesenteric artery in Group II, (227.1+/-15.1% vs. 152.8+/-11.7% in controls) (p<0.05). Intestinal MDA concentration, a marker of oxidant injury, increased from 39.87+/-9.41 nmol/g to 67.8+/-8.8 nmol/g in group II (p<0.01), and to 94.8+/-7.56 nmol/g in Group III (p<0.001). Wet-to-dry intestine weight ratio increased from 3.62+/-0.12 to 4.28+/-0.17 in Group II (p<0.01), to 4.62+/-0.14 in Group III (p<0.001). These data indicate that although the intestines of the animals subjected to intestinal I-R are seriously injured, the smooth muscle relaxation of major conduit arteries was not affected.

Hemodynamic changes in the early phase of artificially created arteriovenous fistula: color Doppler ultrasonographic findings.

The objective of this study was to evaluate hemodynamic variables in arteriovenous fistulas by color Doppler ultrasonography. This study involved 28 patients with chronic renal failure who were sent to surgery clinic for creation of an arteriovenous fistula of the Brescia-Cimino type. Patients were evaluated preoperatively and on the first and seventh days postoperatively by a color Doppler ultrasound machine with a 7.5 MHz linear probe. The distal radial artery was examined preoperatively and the fistula itself postoperatively. Changes in the fistula size and the velocity, volume, and resistive index of the distal radial artery were recorded. Postoperatively the radial artery diameter, systolic flow rates, and volume flow had increased significantly, especially on the first day, in comparison to preoperative values. Resistive index values has decreased significantly at both the first and the seventh days postoperatively. Color Doppler ultrasonography is a very effective method in the evaluation of hemodynamics of arteriovenous fistulas in hemodialysis patients. It will allow an understanding of the pathology in nonfunctioning fistulas or of the cause of complications that develop secondarily.

Effect of haemodynamic variables on surgically created arteriovenous fistula flow.

BACKGROUND: The immediate success and flow rate of a newly constructed arteriovenous fistula is dependent on several haemodynamic factors affecting the inflow and outflow of the fistula. METHODS: In this study we evaluated the effect of preoperative arterial blood pressure, arterial inflow, subclavian venous flow, and operative venous outflow resistance on the immediate success, with special reference to the quantity of the fistula flow in 32 patients undergoing internal arteriovenous fistula operations. Flow measurements were done by utilizing colour flow duplex imaging and measurement of venous resistance of the fistula vein was accomplished indirectly by a newly developed simple system. RESULTS: A preoperative subclavian venous flow rate of less than 400 ml/min was associated with higher rate of immediate failures (P < 0.05) with a negative predictive value of 100% with 100% sensitivity. Regarding immediate failures, no other haemodynamic measurement was found to affect the success of a newly constructed fistula significantly. A linear correlation between the measured haemodynamic values and the quantity of postoperative fistula flow was not found. However, an arterial inflow value of > or = 40 ml/min was associated with higher fistula flow rates (P < 0.05). CONCLUSIONS: The immediate success and flow of a newly constructed arteriovenous fistula is mainly dependent on arterial inflow and subclavian venous flow. An arterial inflow rate of 40 ml/min or more and subclavian venous flow rate of 400 ml/min or more measured by colour flow duplex imaging prior to the operation will be associated with better outcomes, and therefore the use of colour flow duplex imaging is warranted during the evaluation of patients who are candidates for an arteriovenous fistula operation.

Effect of lactulose on bacterial translocation.

OBJECTIVE: To find out if lactulose can prevent the bacterial translocation that is induced by obstructive jaundice in rats. DESIGN: Laboratory experiment. SETTING: Teaching hospital, Turkey. MATERIAL: 50 male Wistar-albino rats. INTERVENTIONS: 10 rats were not operated on and used as controls; 20 rats underwent laparotomy and sham ligation of the common bile duct (CBD); 20 had the CBD ligated alone; and 20 had the CBD ligated and were given oral lactulose 2 ml/day until death. All rats were killed after 14 days. MAIN OUTCOME MEASURES: Presence of Escherichia coli in mesenteric lymph nodes (MLN), and bacterial overgrowth as indicated by counts of E coli in the caecum. RESULTS: There was significantly less bacterial translocation to MLN in the group that had been given lactulose compared with CBD-ligated and lactulose not given (2/20 compared with 8/20, p = 0.06). There was also a significant reduction in the number of Gram negative bacteria in that group (p = < 0.01). CONCLUSION: Lactulose seems to reduce the incidence of translocation from the gut to MLN in rats with obstructive jaundice.

Surgical treatment of advanced alveolar hydatid disease of the liver: a report of five cases.

We report herein the cases of five patients with alveolar hydatid disease (AHD) of the liver who were diagnosed and underwent surgery at the Department of Surgery of Ankara University between 1989 and 1994. In all five patients, the final diagnosis was established by frozen section of the lesion during laparotomy. Lesions of AHD were found only in the liver. Hepatic resections including right lobectomy and segmentectomy were performed in three patients while palliative procedures were carried out in the remaining two patients with unresectable disease. There was no operative mortality, and only one late death occurred 3 years after the hepatic resection. In this paper, we present the clinical and operative findings of these five patients and their outcomes, followed by a review of the surgical treatment of AHD.

Treatment of acute sigmoid volvulus.

Thirty-eight patients were treated for acute sigmoid volvulus in 9 years. Non operative decompression treatment was performed in 7 patients, and 31 patients underwent exploratory laparatomy (25 for suspected bowel necrosis and 6 for unsuccessful non operative treatment). Sigmoid resection and reanastomosis was performed in 5 of the 12 cases with gangrenous bowel and 10 of the 19 with viable bowel. There were no mortality and no morbidity related to the anastomoses. The results have shown that reanastomosis after sigmoid resection could be performed safely in selected cases of acute sigmoid volvulus even if there is bowel gangrene.