Biomedical subjects

J Fevang

Publications and source records attributed to J Fevang.

8 recordsLinked to original sources

PubMed2004

Fluid resuscitation improves intestinal blood flow and reduces the mucosal damage associated with strangulation obstruction in pigs.

BACKGROUND: Strangulation obstruction of the small bowel is associated with local and systemic circulatory changes, local loss of fluid, and damage of the strangulated bowel segment. We wanted to examine to which extent these changes can be prevented by intravenous fluid administration. MATERIALS AND METHODS: In anesthetized pigs, strangulation obstruction was induced by increasing the pressure in a baby pressure gasket placed around a loop of ileum until venous pressure in the loop reached 50 mm Hg. During the strangulation period (180 min), a group of eight animals (Fluid(min) group) received 10 ml. kg(-1). hour(-1) Ringer acetate solution intravenously, whereas another eight animals (Fluid(max) group) received 55 ml. kg(-1). hour(-1) Ringer acetate solution intravenously. Blood flow to the strangulated bowel was measured by transit time flowmetry and colored microspheres. After completed experiments, whole wall samples of the strangulated loop were selected for microscopy. RESULTS: In the Fluid(min) group, the heart rate increased, the arterial pressure decreased markedly, and the urine output decreased toward zero. In the Fluid(max) group, the heart rate and arterial pressure remained fairly constant and the urine output increased. Blood flow to the strangulated bowel decreased in both groups, but significantly more in the Fluid(min) group. The intestinal blood flow was highly dependent on the arterial blood pressure. The strangulated mucosa showed markedly more damage in the Fluid(min) group than the Fluid(max) group. The degree of mucosal damage correlated linearly with the mucosal blood flow. CONCLUSION: The administration of large amounts of fluid to animals with strangulation obstruction normalized the arterial pressure and improved the intestinal blood flow thus minimizing damage to the intestinal mucosa.

Animals↗

PubMed2001

Role of endothelin in the circulatory changes associated with small bowel strangulation obstruction in pigs: effects of the endothelin receptor antagonist bosentan.

BACKGROUND: We have previously shown that experimental strangulation obstruction leads to increased release and concentration of endothelin-1 (ET-1) in venous blood from the strangulated bowel loop. The present study focuses on the microcirculatory effects of the released ET-1 in strangulation obstruction. METHODS: In anesthetized pigs strangulation obstruction was induced by increasing pressure in a baby pressure gasket placed around a loop of ileum until venous pressure reached 45 mm Hg. The pigs were randomly allocated into two groups. The nonselective ET(A)/ET(B) antagonist bosentan was administered intravenously (5 mg kg(-1)) to eight pigs (bosentan group) 30 min before strangulation, which was maintained for 90 min. Another eight pigs were treated in same manner except for the bosentan injection (control group). RESULTS: The concentration of ET in arterial and intestinal venous blood increased markedly after intravenous administration of bosentan. Intravenous infusion of bosentan was followed by a reduction in systemic arterial blood pressure. Bosentan reduced vascular resistance and increased blood flow in the normal intestinal mucosa. It also reduced muscularis blood flow in the beginning of the experiment. In strangulated small bowel bosentan inhibited the increase in vascular resistance usually caused by strangulation obstruction. Muscularis blood flow in strangulated small bowel was not affected by bosentan. CONCLUSION: Endothelin is involved in the normal regulation of arterial blood pressure. The increase in vascular resistance associated with strangulation obstruction is caused mainly by locally released endothelin.

Animals↗

PubMed2000

Upper gastrointestinal contrast study in the management of small bowel obstruction--a prospective randomised study.

OBJECTIVE: To find out whether contrast radiography helps to resolve small bowel obstruction. DESIGN: Prospective randomised trial. SETTING: University hospital, Norway. SUBJECTS: 98 consecutive patients with symptoms of small bowel obstruction and a plain abdominal radiograph that confirmed the diagnosis. INTERVENTIONS: The patients were randomly allocated to receive a mixture of barium and sodium diatrizoate (Gastrografin) (n = 48) or not (n = 50). Both groups were followed up clinically and by repeated abdominal films. MAIN OUTCOME MEASURES: Non-operative resolution of small bowel obstruction; number of patients with strangulated bowel; bowel resections; mortality; complications; hospital stay; and time from admission to operation. RESULTS: No significant differences were observed between the groups in the incidence of non-operative resolution (31/48 in contrast group, 35/50 in control group, OR: 0.89), strangulation obstruction (1/48 in contrast group, 4/50 in control group, OR: 0.24), bowel resection (3/48 in contrast group, 4/50 in control group, OR: 0.76), complications (8/48 in contrast group, 5/50 in control group, OR: 1.80), mortality (3/48 in contrast group, 1/50 in control group, OR: 3.26), and hospital stay (0-7 days: 34/48 in contrast group, 38/50 in control group, p = 0.95). The contrast group had a shorter interval between admission and operation than the control group (0-24 hours: 12/48 in contrast group, 3/50 in control group, p = 0.005). CONCLUSION: The contrast examination did not contribute to the resolution of small bowel obstruction.

Adult↗

PubMed2000

Complications and death after surgical treatment of small bowel obstruction: A 35-year institutional experience.

OBJECTIVE: To study factors influencing complications and death after operations for small bowel obstruction (SBO) using multifactorial statistical methods. SUMMARY BACKGROUND DATA: Death after surgery for SBO is believed to be influenced by factors such as old age, comorbidities, bowel gangrene, and delay in treatment. No studies have been reported in which adverse factors related to death and complications have been systematically investigated with modern statistical methods. METHODS: The authors studied retrospectively 877 patients who underwent 1,007 operations for SBO from 1961 to 1995. Patients with paralytic ileus, intussusception, and abdominal cancer were excluded. Odds ratios for death, complications, postoperative hospital stay, and strangulation were calculated by means of logistic regression analyses. RESULTS: Death and complication rates decreased during the study period. Old age, comorbidity, nonviable strangulation, and a treatment delay of more than 24 hours were significantly associated with an increased death rate. The rate of nonviable strangulation increased markedly with patient age. Major factors increasing the complication rate were old age, comorbidity, a treatment delay of more than 24 hours, and the need for repeat surgery. CONCLUSION: Death and complication rates after SBO decreased from 1961 to 1995. Major factors influencing the rates were age, comorbidity, nonviable strangulation, and treatment delay. Nonviable strangulation was more common in old patients.

Age Factors↗

PubMed1999

Endotoxin and cytokine release in strangulation obstruction and in partial occlusion of the mesenteric artery in pigs.

BACKGROUND: The study was performed to determine if endotoxin or the cytokines interleukin-1 (IL-1), interleukin-6 (IL-6) and tumor necrosis factor (TNF) are liberated from strangulated or partially ischemic small bowel. METHODS: Strangulation obstruction was induced by elevating pressure in a gasket placed around a loop of ileum until venous pressure reached 50 mm Hg. Low arterial flow in a loop of ileum was produced by arterial clamping reducing blood flow by 70%. A proximal bowel loop was used for control. Arterial blood flow was measured by transit time flowmetry. Blood samples were collected before and after 30, 90 and 180 min of strangulation or clamping. Plasma levels of endotoxin and cytokines (TNF, IL-1 and IL-6) were measured by limulus amebocyte lysate test and bioassays, respectively. RESULTS: Strangulation obstruction caused more extensive mucosal damage than arterial clamping. Strangulation was followed by markedly increased venous concentration and release of IL-6 in the strangulated loop. Partial arterial occlusion did not cause increased release of IL-6. Strangulation or partial clamping did not influence the concentration of endotoxin, IL-1 or TNF in intestinal venous blood. CONCLUSIONS: Strangulation obstruction causes increased release of IL-6 to intestinal venous blood. IL-6 levels did not increase after 70% reduction of arterial blood flow. The early IL-6 increase was not detected in systemic blood. Strangulation did not cause early changes in plasma levels of endotoxin, TNF or IL-1.

Animals↗

PubMed1998

Release of endothelin-1 in strangulation obstruction of the small bowel in pigs.

Evidence has been provided that increased portal vein pressure results in increased release of endothelin-1 (ET-1). Strangulation obstruction is associated with increased venous pressure, and we wanted to determine if it is associated with increased local release of ET-1 and elevated concentration of ET-1 in systemic blood. Strangulation obstruction was induced by elevating pressure in a gasket placed around a loop of ileum until venous pressure reached 50 mm Hg. Ischemia in a bowel loop was induced by arterial clamping, reducing blood flow by 70%. Blood samples were collected before and after 30, 90, and 180 min of strangulation or ischemia. ET-1 was determined by radioimmunoassay following acidification and extraction on C18 columns. In strangulated loop the blood flow decreased by 70%. ET-1 concentration remained around 5 pg/ml in arterial blood, increased fourfold in strangulated venous blood, and remained unchanged in venous blood from control bowel. The release of ET-1 from the strangulated loop to blood increased twofold. Ischemia resulted in reduced release of ET-1. It is concluded that strangulation obstruction causes increased release of ET-1 to venous blood in the strangulated loop, but not increased ET-1 concentration in systemic blood. The increased ET-1 release was probably due to increased venous pressure, not to low blood flow.

Animals↗

PubMed1991

Role of blood flow in adaptive protection of the cat gastric mucosa.

This study was designed to test the hypothesis that adaptive cytoprotection is related to increased blood flow caused by mild irritants. The stomach of cats was perfused with saline at pH 1.0. Mucosal blood flow was determined by radioactive microspheres, and celiac artery blood flow was measured by Doppler ultrasound. Gastric blood flow was left undisturbed or reduced by tightening a vessel loop around the celiac artery. Mucosal exposure to absolute ethanol for 2 minutes caused extensive damage to the surface epithelium, the pits, and the upper half of the glands. Pretreatment of the mucosa with 2 mol/L NaCl for 10 minutes prevented the development of mucosal lesions after subsequent application of absolute ethanol. The mucosal blood flow increased markedly after treatment with 2 mol/L NaCl. When this hyperemic response was inhibited by reducing celiac artery blood flow, ethanol caused lesions of similar degree as in animals not pretreated with 2 mol/L NaCl. A highly significant correlation was obtained between mucosal blood flow, as determined just before the application of ethanol, and the degree of ethanol-induced damage. At a chosen level of blood flow, ethanol caused the same degree of damage with or without pretreatment with 2 mol/L NaCl. In conclusion, high mucosal blood flow caused by a mild irritant is an important factor in adaptive gastric protection. With the present experimental setup, the protection could be fully explained as a result of the hyperemic response caused by 2 mol/L NaCl.

Analysis of Variance↗

PubMedDate not supplied

Hemodynamic changes associated with strangulation obstruction in cats.

While changes in blood flow associated with simple intestinal obstruction have been studied extensively, little is known about blood flow changes associated with strangulation obstruction. Closed loop strangulation was produced in anesthetized cats by means of a baby pressure gasket. Intestinal blood flow was measured by transit time flowmetry. Blood pressure was measured in a carotid artery and in veins of a closed loop of small intestine. The gasket pressure was increased stepwise in 10 mm Hg increments after which the intestinal venous pressure was kept constant at 50 mm Hg for 5 h. Increasing gasket pressure was followed by a corresponding increase in venous pressure in the closed bowel loop. Blood flow in the closed loop decreased with increasing venous pressure and was closely related to the arteriovenous perfusion pressure under stepwise increase of the gasket pressure and during prolonged periods with increased venous pressure. At constant elevated venous pressure the intestinal blood flow was determined by the arterial pressure. The vascular resistance in the closed loop increased exponentially with increasing venous pressure and especially at very low blood flow. In conclusion, we have found that strangulation obstruction is associated with increased venous pressure in the closed loop which contributes to maintaining intestinal blood flow during the obstruction.

Animals↗