Biomedical subjects

M Kuhmann

Publications and source records attributed to M Kuhmann.

7 recordsLinked to original sources

PubMed1996

Postoperative alpha 2-adrenergic stimulation attenuates protein catabolism.

The metabolic effects of continuous intravenous (IV) application of the alpha 2 agonist clonidine were evaluated by assessment of nitrogen economy and postaggression endocrine patterns. Twenty-four patients undergoing abdominothoracic esophageal cancer resection were studied. Thirteen of these patients with alcohol abuse were treated postoperatively with IV clonidine for prevention of alcohol withdrawal syndrome. Eleven patients who were not treated with clonidine served as controls. All patients were treated in a standardized manner in regard to surgical technique, balanced anesthesia, and postoperative intensive care treatment, including thoracic epidural analgesia with bupivacaine and fentanyl. Isonitrogenous and isocaloric nutrition was comparable in all patients. A significantly improved cumulated 6-day nitrogen balance was found in clonidine-treated patients (-1.5 +/- 4.9 g nitrogen) compared to the control group (-17.6 +/- 4.2 g nitrogen) (P < 0.05). The main reason for improved nitrogen economy may be clonidine-induced growth hormone (GH) release. The pattern of insulin-like growth factor I (IGF-I) and insulin-like growth factor binding protein 3 (IGFBP-3) concentrations could support this hypothesis.

Adrenergic alpha-Agonists↗

PubMed1996

A new method for continuous intramucosal PCO2 measurement in the gastrointestinal tract.

Gastric tonometry has been introduced for the early detection of impaired splanchnic perfusion by determination of the intramucosal PCO2. However, due to methodological problems, i.e., instability of CO2 in water, to assess the exact intramucosal PCO2 with the nasogastric tonometer is unreliable. The present in vitro and in vivo study examines a new fiberoptic PCO2 sensor for the continuous determination of the intramucosal PCO2 and compares these data with that of conventional tonometry. In an in vitro experiment the fiberoptic PCO2 sensor was used to determine the PCO2 of water and humidified air with predefined CO2 values. In both media, predefined CO2 values (35, 42, 49 mm Hg) could be assessed exactly after 9 min of equilibration with a maximum deviation less than 3.5%. In contrast, the values obtained by conventional tonometry showed larger differences. In in vivo experiments on six pigs PCO2 differences were induced by ventilatory changes to validate the fiberoptic PCO2 sensor. Under anesthesia a laparotomy was performed, the ileum punctured, and the fiberoptic PCO2 sensor introduced into the ileal lumen. Arterial PCO2 (PaCO2), mesenteric venous PCO2 (PmvCO2), and intramucosal PCO2, (PiCO2) were determined during normoventilation, hypoventilation, and hyperventilation. During hypoventilation the PiCO2 increased from 53.8 +/- 2.0 mm Hg (PaCO2 = 39.8 +/- 1.4 mm Hg, PmvCO2 = 48.7 +/- 2.7 mm Hg) to 66.5 +/- 4.9 mm Hg (PaCO2 = 52.7 +/- 3.1 mm Hg, PmvCO2 = 62.4 +/- 5.7 mm Hg). With hyperventilation the PiCO2 decreased to 46.8 +/- 2.5 mm Hg (PaCO2 = 29.8 +/- 1.8 mm Hg, PmvCO2 = 41.8 +/- 2.7 mm Hg). The coefficient of correlation (r2) between PiCO2 and PaCO2 was 0.82, and between PiCO2 and PmvCO2 0.94. The fiberoptic PCO2 sensor can determine PiCO2 in a precise and reliable manner, and can continuously record fast intraluminar changes of CO2 in the ileum that were caused by ventilatory changes. The fiberoptic PCO2 sensor is the only method that reliably monitors PiCO2 in the gastrointestinal tract. By the direct measurement of PCO2 the methodological problems associated with the conventional nasogastric tonometry are abolished.

Animals↗

PubMed1996

Gastric tonometry: precision and reliability are improved by a phosphate buffered solution.

OBJECTIVE: To compare a phosphate buffered solution with normal saline as tonometric fluid in intramucosal PCO2 measurement in humans. DESIGN: Prospective, unblinded comparison. SETTING: Postsurgical critical care unit of a university hospital. PATIENTS: Six septic patients. INTERVENTIONS: Two tonometric probes were positioned in the gastric lumen in each patient. One tube was used for conventional tonometry (saline-filled balloon), while phosphate buffered solution was instilled into the second tube. MEASUREMENTS AND MAIN RESULTS: PCO2 was determined with three blood gas analyzers (ABL 2 [Radiometer, Copenhagen, Denmark], Corning 288 [Ciba Corning Diagnostics GmbH, Neuss, Germany], and StatProfile 9 Plus [Nova Biomedical, Waltham, MA]). Eight parallel PCO2 measurements per patient were evaluated, yielding a total of 48 measurements with each tonometric solution. Intrainstrumental comparison of the PCO2 determinations demonstrated an increase of 12.3 +/- 9.9% for ABL 2, 3.10 +/- 12.9% for Ciba Corning 288, and 101.2 +/- 31.5% for StatProfile 9 Plus with the phosphate buffered solution. The PCO2 values were decreased by the following amounts when the three instruments were compared, using the saline method: 14.2 +/- 8.2% (Ciba Corning 288 vs. ABL 2); 40.7 +/- 9.9% (StatProfile 9 Plus vs. ABL 2); and 30.9 +/- 9.35% (StatProfile 9 Plus vs. Ciba Corning 288). The difference in PCO2 determination, resulting from the different instrument designs, were significant between the three blood gas analyzers (p<.001). In addition, the variance of the intramucosal PCO2 values was significant between blood gas analyzers (p<.001) with normal saline as tonometric solution, but not with phosphate buffered solution. The coefficients of determination between PCO2 values in saline and phosphate buffered solution were r2=.85 for ABL 2, r2=.81 for Ciba Corning 288, and r2=.74 for StatProfile 9 Plus. When all 48 PCO2 values were analyzed, the interinstrumental coefficients of determination within a method for saline (and for phosphate buffered solution in parenthesis) were:r2=.83 (.92) between ABL 2 and Ciba Corning 288, r2=.72 (.92) between ABL 2 and StatProfile 9 Plus, and r2=.81 (.98) between Ciba Corning 288 and StatProfile 9 Plus. CONCLUSIONS: A considerable instrumental bias in PCO2 analysis is observed when saline is used as tonometric fluid in gastric tonometry, thus preventing a reliable determination of intramucosal pH. The present in vivo data show that the accuracy and reliability of intramucosal pH measurement can be improved by the use of phosphate buffered solution as tonometric fluid.

Adult↗

PubMed1995

Repeated administration of recombinant human insulin-like growth factor-I in patients after gastric surgery. Effect on metabolic and hormonal patterns.

OBJECTIVE: The primary objective of this investigation was to evaluate the anticatabolic effects of repeated subcutaneous administration of recombinant human insulin-like growth factor-I (rhlGF-I) in patients after gastric surgery. SUMMARY BACKGROUND DATA: The anabolic and protein-sparing effects of growth hormone are primarily mediated by IGF-I. Malnutrition and catabolic states result in increasing blood levels of growth hormone and decreasing levels of IGF-I. Experimental data showed that exogenous IGF-I could attenuate or reverse catabolism. METHODS: After giving their written informed consent, 38 male and female patients undergoing gastrectomy (age 40-75 years, body mass index 17-30 kg/m2) were treated with 80 micrograms/kg body weight rhlGF-I or placebo in a prospective, randomized, double-blind study for 5 consecutive days. Patients received a standardized total parenteral nutritional regimen with 3 g/kg body weight glucose and 0.1 g/kg body weight nitrogen. Nitrogen balance and 3-methylhistidine excretion were measured daily. Hormone profiles (IGF-I, IGFBP1, IGFBP3, cortisol, insulin, glucagon, triiodothyronine [T3], levothyroxine [T4], and thyroxine-binding globulin) were taken.

Adult↗

PubMed1995

Improved PCO2 measurement in six standard blood gas analysers using a phosphate-buffered solution for gastric tonometry.

The measurement of gastric intramucosal pH serves as a non-invasive technique for early detection of gastrointestinal ischaemia in critically ill patients. The method is based on the determination of the partial pressure of carbon dioxide in a 0.9% saline solution using a standard blood gas analyser. However, the use of standard blood gas analysers leads to an underestimation of carbon dioxide partial pressure in saline. Instrumental biases of six blood gas analysers were investigated using either a saline or a phosphate-buffered solution. Both test solutions were equilibrated with five defined carbon dioxide concentrations. Each blood gas analyser underestimated this defined partial pressure of carbon dioxide with a bias between -3.7% and -57.5% if saline was used. The phosphate-buffered solution considerably improved instrumental precision, resulting in biases between +2.7% and -17.6% Thus, a phosphate-buffered solution increases the accuracy of gastric intramucosal pH measurement.

Blood Gas Analysis↗

PubMed1994

[Glucose-xylitol 35% (1:1) versus glucose 40%. Effectiveness and metabolic effects after major surgery].

Injury and stress are accompanied by a characteristic hormonal response and altered energy utilisation. Hyperglycaemia and negative nitrogen (N) balance are the leading symptoms of the metabolic changes in the post-operative state. In a prospective, randomised study the efficacy and metabolic effects of glucose-xylitol (GX) 35% (1:1) versus glucose (G) 40% were investigated in patients undergoing major surgery. METHOD. Twenty-four patients undergoing abdomino-thoracic oesophageal cancer surgery were treated in a standardised manner. Total parenteral nutrition was administered over 6 days (kg body wt.-1/day): day of surgery 1-1.25 g carbohydrate (CH); 1st postoperative day (POD) 1.5 g CH, 1 g amino acids (AA); 2nd POD 3 g CH, 1.5 g AA, 1.0 g fat; from 3rd POD 3 g CH, 1.5 g AA, 1.5 g fat (CH GX35% (n = 12) or G40% (n = 12), AA Intrafusin 15%, fat Intralipid 20%). Daily and cumulative N balances, blood-G profiles, blood chemistry, and physical parameters were determined. Glucagon and insulin profiles, CH losses, and oxalic acid secretion were measured. RESULTS. Both groups were comparable for age, body mass index, clinical and physical parameters, and blood chemistry. Mean cumulative N balances after 6 days were -12.0 +/- 16.3 g N for GX35% and -5.6 +/- 19.4 g N for G40% (n.s.; Wilcoxon, P < 0.05). Blood G was similar for both groups with values ranging from 130 to 240 mg/dl on the day of surgery and below 150 mg/dl on the consecutive days. In each group 1 patient needed additional insulin therapy. Glucagon and insulin levels did not show a significant difference between the groups. CONCLUSION. No difference in tolerance and efficacy of nutritional support by GX versus G at a dose of 3 g.kg body wt.-1.d in oesophagectomised patients could be observed. Similar blood G profiles were in accordance with comparable glucagon and insulin levels. Because of the high standard deviations of N balances, differences in efficacy could not be proven. A significantly lower level of pseudocholinesterase (PCHE) for G40% on day 7 might indicate enhanced hepatic protein synthesis in the GX group.

Adult↗

PubMed1994

[Safety and tolerance of a new dipeptide-containing amino acid solution DP-Gln 20 versus a conventional amino acid solution Vamin 18EF in patients after elective colon surgery].

OBJECTIVE AND METHODS: Recent studies have demonstrated the important role of glutamine in postoperative metabolism. Using dipeptide-containing amino acid solutions it is possible to enhance glutamine supply. Safety and tolerance of DP-Gln 20 (gly-gln, gly-tyr) and Vamin 18EF were investigated in an open, prospective, randomised study. 16 patients received isonitrogenous parenteral nutrition over 4 days. RESULTS: There was no difference in clinical and biochemical patterns between both groups. Complications and adverse events due to the infused amino acid solutions were not observed.

Adolescent↗