Biomedical subjects

A Schledt

Publications and source records attributed to A Schledt.

4 recordsLinked to original sources

PubMed2002

Dopexamine attenuates microvascular perfusion injury of the small bowel in pigs induced by extracorporeal circulation.

BACKGROUND: Cardio-thoracic surgery with the use of extracorporeal circulation may lead to an impairment of splanchnic perfusion. The aim of this study was to investigate the effect of dopexamine on gastrointestinal microvascular perfusion failure due to extracorporeal circulation. METHODS: Twenty landrace pigs served as laboratory animals. A loop of the terminal ileum was exteriorized for microscopic observation. In 13 animals a partial left-heart bypass (pLHB), with a non-pulsatile pump flow of approximately 50% of the cardiac output, was established for 2 h. Seven animals received a continuous i.v. infusion of 3 micrograms kg-1 min-1 dopexamine from the beginning of pLHB to the end of the experiment. Seven sham-operated animals served as controls. The microcirculatory network was analysed by means of intra-vital microscopy prior to, during pLHB, and 2 h after bypass. RESULTS: Despite normal haemodynamics measured by arterial pressure and cardiac output, pLHB led to significant impairment of microvascular perfusion characterized by arteriolar vasoconstriction, reduction of functional capillary density (FCD) to 30% 2 h after weaning off bypass and diminished blood-cell velocities in submucous venules. Dopexamine attenuated this perfusion impairment, preventing arteriolar vasoconstriction. FCD remained normal. CONCLUSION: Our data demonstrate that treatment with the vasoactive drug dopexamine leads to a significant reduction of the perfusion injury of the small bowel.

Adrenergic beta-Agonists↗

PubMed2001

Influence of steroids on microvascular perfusion injury of the bowel induced by extracorporeal circulation.

BACKGROUND: Extracorporeal circulation is associated with gastrointestinal complications. By means of intravital microscopic methods, we investigated whether preoperative treatment with steroids can attenuate the impairment of the bowel microcirculation. METHODS: In 20 pigs, a partial left heart bypass (pLHB) was established. A loop of the terminal ileum was exteriorized for intravital-microscopic observation. Seven sham-operated animals served as controls. In 13 animals, pLHB was established for 2 hours with a flow rate of 2,000 mL per minute; 7 of the animals received 20 mg/kg body weight prednisolone preoperatively. The microcirculatory network was analyzed before, during pLHB, and 2 hours after bypass. RESULTS: Despite unchanged macro-hemodynamics, pLHB resulted in a significant microvascular perfusion injury of the small bowel. Arteriolar vasoconstriction and a reduction of perfused capillaries per unit area (functional capillary density) to 30% of prebypass values could be found. Blood cell velocities were reduced in submucuous collecting venules. In the steroid-treated animals, the functional capillary density remained normal. In addition, arteriolar vasoconstriction could be prevented. CONCLUSIONS: Treatment with prednisolone largely prevents the microcirculatory alterations in the small bowel induced by extracorporeal circulation.

Animals↗

PubMed2000

Decrease of cholestasis under "continuous extracorporeal stool transport (CEST)" in prematures and neonates with stomas.

According to recent studies, the percentage of neonates suffering a combination of very low birth weight (VLBW) and intestinal malformation or diseases that require surgery has increased. As opposed to mature newborn, split stoma is the therapy of choice in VLBW infants. These neonates and patients with other causes for a congenital or acquired short-bowel syndrome usually require parenteral nutrition and have a high risk of a cholestasis. Until 1993, stoma patients were treated with a special diet in our department, but depending of the stoma site often required parenteral nutrition, while the non-used distal bowel was irrigated with an isotonic electrolyte solution. With this regime, up to 38.5% of the treated patients (10126) were found to have a hyperbilirubinemia (> 3 mg/dl) after the 21st day of life. 1994, we started to use a device that continuously transfers the intestinal chylus from the proximal into the aboral bowel via a pump like a continuous extracorporeal stool transport (CEST). In this study, we evaluated the risk of cholestasis by comparison of the prospectively investigated group (CEST-group 1994-1998) of 33 infants with the results of the retrospectively studied group of 26 patients operated on between 1987 and 1993. We found a significantly lower risk of cholestasis in the CEST-Group (12.9% versus 38.5%; p<0.04). Only 3% of our patients with CEST (one patient) required permanent parenteral nutrition, compared to 50% of the conventionally treated patients.

Bilirubin↗

PubMedDate not supplied

Extracorporeal circulation induced microvascular perfusion injury of the small bowel.

Gastrointestinal complications following cardiopulmonary bypass (CPB) are relatively uncommon, but are associated with a high mortality rate. Impairment of bowel perfusion during and following CPB may serve as a trigger for the development of multiorgan failure. The aim of our study was the development of a new animal model allowing quantitative analysis of small bowel microcirculation during and after CPB. Twelve Landrace pigs served as laboratory animals. A 15-cm loop of the terminal ileum was exteriorized for microscopic observation. In 6 animals, a normothermic, partial left heart bypass (pLHB) was established for 2 h with a flow rate of 2,000 ml/min. Arterioles, collecting venules and the capillaries of the small bowel were recorded for the analysis of the microcirculation. All parameters were recorded prior to, during pLHB and up to 2 h after weaning off the bypass. Six sham operated animals served as controls. Despite unchanged hemodynamics, pLHB leads to microvascular perfusion disturbances of the small bowel. In pLHB animals, blood cell velocity in postcapillary venules (30-70 microm) was significantly decreased during and following bypass. Capillary density was also reduced during bypass and decreased even further after pLHB to only 30% of the control values. With this new large animal model for quantitative assessment of microvascular perfusion of the small bowel during CPB, it could be clearly demonstrated that partial normothermic left heart bypass leads to a significant disturbance of the small bowel microcirculation even under stable hemodynamic conditions.

Animals↗