Search PubMed⌕ Search

Biomedical subjects

K Lenz

Publications and source records attributed to K Lenz.

At least 109 records · Page 6Linked to original sources
PubMed1988

[Prevention of stress hemorrhage in an internal medicine intensive care station: sucralfate versus ranitidine].

Stress ulcer bleeding is a serious complication of critical illness and is associated with increased morbidity and mortality. For the prophylaxis of stress ulcers, antacids, H2-blockers, or sucralfate are prescribed. While H2-blockers inhibit the secretion of gastric acid, sucralfate appears to provide protection without reducing levels of gastric acid. Inhibition of acid secretion increases gastric pH, allowing bacterial overgrowth of the stomach by Gram negative bacteria, which colonize the pharynx and trachea and increase the risk of nosocomial pneumonia. For this reason, H2 blockers appear disadvantageous, though they offer adequate prophylaxis for stress ulcer bleeding. As it does not increase gastric pH, sucralfate provides adequate protection against Gram negative gastric overgrowth, however its prophylactic efficacy is not generally accepted. Therefore, we compared the H2-blocker ranitidine to sucralfate in the prophylactic treatment of stress ulcer bleeding and studied the incidence of positive bacteriological findings in the blood and bronchial secretions of the two groups. In a randomized study, 84 patients undergoing general intensive care received either ranitidine (6 x 50 to 6 x 100 mg daily i.v.) or sucralfate (6 x 1 g via gastric tube or per os). Both groups were comparable with respect to age, underlying disorders, and factors predisposing to the development of stress ulcers.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[Energy metabolism in patients with severe heart failure].

Resting energy expenditure was measured by indirect calorimetry in 11 patients (8 men, 3 women) with severe heart failure. The study was done after an over night fast (10-12 h). 5 patients suffered from idiopathic cardiomyopathy, 5 patients from coronary heart disease and 1 patient from congestive heart failure following from viral myocarditis. The cardiac index was 2.09 +/- 0.5 l/min/m2, the pulmonary capillary wedge pressure 24.6 +/- 8.0 mm Hg. Resting energy expenditure was 1.175 +/- 0.176 kcal/min/1.73 m2. The basal energy expenditure calculated according to Harris and Benedict was 1.008 +/- 0.055 kcal/min/1.73 m2. The difference was statistically significant (p less than 0.05). Respiratory quotient was 0.775 +/- 0.06 as a result of a high oxidation rate for fat (64.8% of total energy expenditure). These results show that after an overnight fast the caloric requirements of patients with severe heart failure are increased. This increased energy expenditure could be an explanation for the malnutrition often found in patients with severe chronic heart failure.

Adult↗
PubMed1987

[Effect of high-dose prednisolone on lung fluid in patients with non-cardiogenic lung edema].

The influence of high-dose prednisolone on extravascular lung water (EVLW) was studied in a randomized trial in patients with noncardiac pulmonary edema. The patients were treated every 6 hours for 48 hours with 2 g of prednisolone-hemisuccinate or placebo. In the prednisolone-group (n = 7) EVLW decreased from 16.4 +/- 6.2 before to 11.8 +/- 5.1 ml/kg after treatment (p less than 0.05). Additionally alveolar-arterial oxygen gradient (AaDO2/FiO2), pulmonary vascular resistance and heart rate decreased, while arterial oxygen tension (PaO2/FiO2) and mean arterial pressure increased (p less than 0.05). In the placebo-group (n = 7) EVLW increased slightly from 17.5 +/- 3.1 before to 19.3 +/- 10.3 ml/kg after treatment. Additionally all other parameters did not change significantly in this group. Although no statistical significant difference was found between the two groups of treatment, a decrease in EVLW was observed in all prednisolone-treated patients, whereas a pronounced increase in EVLW was found in 3 placebo-treated patients. Probably, those patients would have benefited from high-dose prednisolone treatment. High-dose prednisolone reduced EVLW and improved hemodynamics and gas exchange in patients with noncardiac pulmonary edema, whereas placebo did not achieve comparable effects. Therefore, high-dose prednisolone appears beneficial in noncardiac pulmonary edema in respect of EVLW, hemodynamics, and gas exchange.

Adult↗
PubMed1987

[Hemofiltration for the reduction of lung fluid in ARDS?].

Hemofiltration has been advocated for reduction of extravascular lung water (EVLW) in both clinical and experimental ARDS. The influence of hemofiltration on EVLW was studied retrospectively in 10 patients with this syndrome. After 2 to 38 hours' hemofiltration net fluid balance was -3640 +/- 3609 ml. EVLW remained almost unchanged (from 17.6 +/- 5.4 before to 15.6 +/- 4.1 ml/kg after hemofiltration). In 4 patients a reduction of over 15% in EVLW was achieved, whereas in the remaining 6 patients EVLW changed within a range of +/- 10%. However, hemofiltration caused a decrease in cardiac output and oxygen delivery, thereby adversely affecting its benefits on EVLW and gas exchange. In ARDS hemofiltration should be performed under careful hemodynamic monitoring and only in some of the patients an immediate reduction in EVLW can be achieved.

Adult↗
PubMed1987

Reproducibility of thermal-dye lung water measurements by a lung water computer in critically ill patients.

Reproducibility of thermal-dye extravascular lung water (EVLW) estimation by a lung water computer was studied by performing ten consecutive measurements in 45 critically ill patients. EVLW ranged over a wide spectrum from 187 to 1163 ml (2.4 to 18.6 ml/kg). The mean coefficient of variation of ten consecutive measurements was 13.6%. Spontaneously breathing patients showed significantly (p less than .05) higher coefficients of variation (16.1 +/- 6.8%) than patients on mechanical ventilation (10.8 +/- 4.2%). Other factors affecting reproducibility could not be clearly identified. Because in lung water estimation mean values of consecutive measurements are compared, we defined an EVLW determination as the mean value of three consecutive EVLW measurements. When comparing consecutive EVLW determinations in hemodynamically stable patients, we found in many that consecutive EVLW determinations varied no more than +/- 15%. These differences probably have to be attributed to the reproducibility of EVLW measurements and have to be considered, when changes in thermal-dye lung water measured by a lung water computer are discussed.

Adolescent↗
PubMed1987

Loading and maintenance dose for the determination of amino acid kinetics in plasma.

Intravenous bolus kinetics of amino acids and calculation of the kinetic parameters with an 1-compartment model revealed weak spots. Therefore, a new study design with a loading and maintenance dose and description of the plasma concentration time data with a 2-compartment model was created and studied in 9 healthy volunteers. After an over night fast the amino acid mixture Thomaeamin n 10% was infused with a loading dose of 20 mg AA/kg-1 X min-1 for 5 min and a maintenance dose of 5 mg AA/g-1 X min-1 for 55 min. The postinfusion period lasted 120 min. The PAA was determined with a Biotronic LC 6001 and the kinetic parameters were calculated by a Wang 2200 computer with the TOPFIT program package. The results showed mean values (means +/- SE) of the volume distribution between 4.7 +/- 0.6 till 9.4 +/- 1.8 liters, an elimination rate constant of 1.7 +/- 0.5 till 11.0 +/- 2.0 h-1, a total clearance of 186 +/- 37 till 846 +/- 66 ml X min-1 and transfer or endogenous production rate between 12 +/- 0.8 till 135 +/- 16 mumol kg-1 X h-1. The total transfer amounts to 17.6 mmol kg-1 X d-1 (= 2.2 g AA/kg-1 X d-1). It can be concluded that an optimal study design for the investigation of AA kinetics should increase the PAA levels 2-3 fold above basal during the infusion period.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[Cardiovascular function in liver cirrhosis].

The hemodynamic pattern in patients with cirrhotic liver disease shows a hypercirculatory state, with elevated cardiac output and decreased systemic vascular resistance. Studies on myocardial function gave different results, whereby non hepatic factors as a cause of myocardial dysfunction are reasonable. Decreased vascular resistance is predominantly caused by an accumulation of vasodilating substances. A dysfunction of vasoconstricting systems could not be found. A previously discussed interference of the sympathetic nervous system could not be confirmed in further studies. This hypercirculatory state may be catastrophic in hypovolemic states, as in acute bleeding, or concomitant septic hyperdynamic states, because the initial compensatory mechanisms are not available any more.

Blood Pressure↗
PubMed1987

Pharmacokinetics of ceftazidime and netilmicin in patients with sepsis.

The pharmacokinetics of ceftazidime and netilmicin were evaluated under septicemic conditions. In a longitudinal study, both drugs were administered simultaneously (ceftazidime 2.0 g 20 min constant i.v. infusion and netilmicin 150 mg i.v. bolus injection) every 12 hours to patients who had a positive blood culture and hyperdynamic circulatory functions. Twenty-four hours after the first period of this pharmacokinetic study, identical parameters were evaluated under dipyrone induced normothermic conditions. The mean residence time and the volume of distribution was significantly altered during septicemia compared to normal conditions. With respect to the relative distribution properties ceftazidime tended to be distributed to a greater extent to the tissue compartment, whereas netilmicin showed an opposite behaviour. Beside significant correlations of absolute values, i.e. blood volume vs. volume of distribution, and relative values, i.e. total peripheral resistance vs. extraction rate, all other attempts failed to show any meaningful correlation. Owing to the heterogenous alterations of metabolic and hemodynamic functions and pharmacokinetic parameters, respectively, the data gained from this study do not allow any statistically validated conclusion regarding the pathophysiological mechanisms involved, although these findings are in accordance with animal experiments.

Adolescent↗
PubMed1986

[Prevention of stress ulcer in intensive care patients].

Critically ill patients are prone to stress-induced ulcerations in the upper gastrointestinal tract, which might lead to life-threatening bleeding. Therefore, an effective stress ulcer prophylaxis is absolutely indicated and H2-blocking agents, anticholinergics, antacids, sucralfate, enteral nutrition and prostaglandin E analoges are recommended. H2-blocking agents seem to provide effective prophylaxis, but severe side effects seem to limit their application. Most of all, as they are less effective as antacids and as they cause considerable costs. Additionally H2-blocking agents elevate gastric pH, thereby favouring microbic colonisation of gastric juice. Microorganism from gastric juice may reach the tracheobronchial system and lead to nosocomial pneumonias. The contaminated gastric juice may also be considered as endogenous source for sepsis and entero-colitis. The anticholinergic agent pirenzepine does not increase gastric pH and seems to be effective in neurological and neurosurgical intensive care patients. Antacids are effective in stress ulcer bleeding prophylaxis, but favour bacterial overgrowth, are badly tolerated by patients and cause a high amount of nursing time. Sucralfate seems to be as effective as antacids, is better tolerated and does not elevate gastric pH. The remaining acidity of gastric juice blocks bacterial contamination. After all, the smallest costs of effective stress ulcer prophylaxis, makes sucralfate to the medicament of first choice. However, in severely ill patients, a combined stress ulcer prophylaxis with two or more agents seems to be necessary.

Alprostadil↗
PubMed1986

Fructose-induced hyperlactemia in hyperosmolar syndromes.

Severe hyperlactemia of 8.7, 8.6 and 7.9 mmol/l, respectively, developed in three patients with hyperosmolar syndromes (two hypernatremic, 417 and 415 mosmol/kg H2O; one hyperglycemic 437 mosmol/kg H2O) during rehydration treatment with 5% fructose in water (fructose dosage 0.5 g/kg body wt. per hour). After resolution of the electrolyte disturbances, the infusion of fructose at the same dosage increased the plasma lactate concentration in two of the patients to 4.9 and 4.0 mmol/l, indicating near normalization of hepatic lactate utilization. Thus, in addition to peripheral insulin resistance and decreased muscular glucose utilization, the hyperosmolar state is associated with a reduced tolerance to fructose. This is most likely due to an osmolality-dependent impairment of hepatic gluconeogenesis. In rehydration therapy for hyperosmolar syndromes, fructose-containing infusion solutions should no longer be used.

Acidosis↗
PubMed1986

[The effect of positive end-expiratory pressure (PEEP) on extravascular lung water in intensive care patients].

The use of positive end-expiratory pressure (PEEP) has been highly recommended because of its favourable effects on pulmonary gas exchange and circulation. It was the aim of this study to investigate the influence of PEEP on extravascular lung water (EVLW), which was estimated by the thermal-dye technique. In 12 intensive care patients PEEP was changed every 30 minutes from 0 to 5, 10, 15 and 0 cm H2O, thereby causing a non-significant increase in EVLW of 2, 10, 7 and 1%. Analysis of individual EVLW-dynamics revealed a more than 20% increase in 6 of 7 patients with normal EVLW (5.8 +/- 0.9 ml/kg), whereas this occurred in only one of the five patients with elevated EVLW (10.9 +/- 1.1 ml/kg). Intraindividual regression analysis between EVLW and PaO2/FiO2, AaDO2/FiO2, Qs/Qt, and CO revealed no correlation between these parameters. Therefore, shorttime application of PEEP did not affect EVLW. Patients with normal EVLW were more prone to show increased EVLW during PEEP than patients with elevated EVLW. PEEP-induced improvement of gas exchange and pulmonary shunt were not accompanied by changes in EVLW.

Adult↗
PubMed1986

Hemodynamic, pulmonary, and renal reactions to inadvertent transfusion of outdated blood.

A patient who received an erroneous transfusion of outdated and partly homogenized blood is reported. Although marked hemoglobinemia was present, only transient hemodynamic, pulmonary, and renal alterations were observed. Massive embolism of microaggregates and norepinephrine release might explain our findings. Dopamine (3 micrograms/kg . min) might have beneficial effects on renal function in this pseudohemolytic transfusion reaction.

Blood Preservation↗
PubMed1986

Elimination of amino acids in acute renal failure.

Plasma amino acid concentrations and the elimination of parenterally administered amino acids were investigated in 12 patients with nonhypercatabolic acute renal failure. A distinctive plasma amino acid pattern could be observed: plasma concentrations of phenylalanine and methionine were increased, those of valine and leucine decreased. Of the nonessential amino acids, cystine, taurine und tyrosine had elevated but none of them reduced plasma concentrations. The elimination of amino acids was evaluated in a monocompartment model after bolus injection of an amino acid solution containing essential and nonessential amino acids. Pharmacokinetic parameters of 17 amino acids were calculated. The mean elimination half-time was raised by 25%. The elimination half-time of phenylalanine, methionine, glutamic acid, proline and ornithine was increased. Histidine was the only amino acid with--however insignificantly--accelerated elimination from the intravascular compartment. The total clearance rate and total transfer rate was not altered (107 and 97% of normal, respectively). The clearance of threonine, lysine, serine, glycine and histidine was increased, of valine, phenylalanine, glutamic acid and to a minor degree of methionine was decreased. The transfer rate of methionine, lysine, glycine was elevated, of valine, aspartic acid, glutamic acid and ornithine reduced. The demonstration of these pronounced alterations of amino acid elimination in acute renal failure may have major consequences in parenteral amino acid therapy.

Acute Kidney Injury↗
PubMed1986

Elimination of amino acids in chronic renal failure.

Elimination of parenterally administered amino acids was investigated in patients with chronic renal failure (CRF) (10 on conservative treatment = CT, 13 on regular hemodialysis therapy = HD). In a bolus injection protocol 0.1 g amino acids as a 10% solution containing essential and nonessential amino acids were infused and pharmacokinetic parameters of 17 amino acids were calculated. The mean elimination half life was increased by 40% in CT and 87% in HD (p less than 0.001 CT and HD versus controls). Total clearance was reduced in CT (p less than 0.001 versus HD and controls). In CT clearance of phenylalanine, proline, alanine, histidine and arginine was reduced, of none of the amino acids elevated. In HD clearance of methionine, lysine, aspartic acid and serine was increased, of proline decreased. The total transfer rate was reduced in CT (p less than 0.025 versus controls) and transfer of threonine, aspartic acid, glutamic acid, alanine, histidine and arginine was reduced in these patients. Mainly due to elevated basal plasma concentration transfer of methionine was elevated in CT and HD. In dialysis patients transfer of isoleucine, tryptophan, glycine and serine was increased. Despite variations of absolute values of clearance between the two groups investigated relative clearance rates of amino acids were similar because of a uniform increase of clearance of about 37% in HD compared to CT (p less than 0.001). Results indicate that the elimination of parenterally administered amino acids is grossly altered in uremia and that in patients on CT and HD a uniform elimination pattern can be observed.

Amino Acids↗