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Biomedical subjects

A Laggner

Publications and source records attributed to A Laggner.

At least 37 records · Page 2Linked to original sources

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↗

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↗

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↗

[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↗

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↗

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↗

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↗

Acute effects of pirenzepin on bronchospasm.

The response to pirenzepin, a new acetylcholine receptor blocking agent, was assessed and compared to placebo in patients with reversible bronchoconstriction. A single intravenous injection of 20 mg of pirenzepin induced a significant reduction of airway resistance compared to placebo (p less than 0.05). The anticholinergic substance pirenzepin appears to be useful in the treatment of bronchospasm.

Aged↗

[Circulatory behavior of patients with liver insufficiency].

Haemodynamic data were obtained in 26 patients with hepatic failure admitted to the intensive care unit of the First Department of Medicine, Vienna University. There was a significant increase in heart rate (101 vs 78 beats/min) and decreased diastolic pressure (56 vs 71 mm Hg) as compared with healthy persons. The cardiac index was elevated (5.1 vs 3.5 l/m2) and the total peripheral resistance was lowered (621 vs 1130 dyn/sec/cm-5). The systolic blood pressure was within the normal range except in 8 patients whose illness was complicated by sepsis. In those 8 patients the systolic blood pressure (86 vs 128 mm Hg), the diastolic blood pressure (42 vs 61 mm Hg) and the total peripheral resistance (434 vs 764 dyn. sec. cm-5) were all decreased as compared with patients with hepatocellular disease without sepsis. The decreased total peripheral resistance, however, was not associated with a further increase in the heart rate or stroke volume. On the contrary, in these 8 patients the left ventricular performance was lowered. The increase in cardiac output was not associated with an increase in oxygen consumption in patients without sepsis. Oxygen consumption was increased in patients with hepatocellular insufficiency and sepsis (157 ml/m2 vs 123 ml/m2) and this was accompanied by a diminished oxygen extraction rate (16% vs 26% in these 8 patients.

Adult↗

[Determination of extravascular lung water in critical patients: comparison with radiological, hemodynamic and functional lung findings].

Measurement of extravascular lung water (EVLW) was performed by the thermal-dye technique in 55 critically ill patients. The EVLW values were compared with the corresponding radiographic, hemodynamic and functional pulmonary data. EVLW values revealed a positive correlation with the chest X-ray score (CXR) (r = 0.836; p less than 0.001), mean pulmonary artery pressure (PP) (r = 0.414; p less than 0.01), pulmonary capillary wedge pressure (PCWP) (r = 0.353; p less than 0.01), venous admixture (Qs/Qt) (r = 0.288; p less than 0.05), and alveo-arterial oxygen difference/fraction of inspired oxygen (AaDO2/FiO2) (r = 0.441; p less than 0.001). No correlation was found between EVLW values and colloid-osmotic pressure minus PCWP (COP-PCWP) (r = 0.221). Though different positive correlations between EVLW values and these parameters were found, they cannot replace EVLW measurement. Rather, EVLW measurement provides additional information on the degree of pulmonary edema which is useful in differentiating between cardiac and non-cardiac pulmonary edema and in states of radiologic over- or underestimation of EVLW.

Adult↗

[Bedside chest x-rays and extravascular lung water determination in intensive care patients].

Radiological staging of pulmonary oedema was compared with the determination of extra-vascular lung water by means of a double indicator dilution technique. One hundred and forty-six ward chest radiographs were evaluated and compared with the results of simultaneous measurements of lung water. Seventy-seven cases could be evaluated statistically. Chest x-rays regarded as normal corresponded to extra-vascular lung water of 5 to 9 ml./kg. body weight. Interstitial oedema (radiological stage I and II) corresponded to extravascular lung water levels of 8 to 12 ml./kg. Differentiation of stages I and II was not possible. During stage III, extra-vascular lung water was 15 to 21 ml./kg. A comparative analyses of these findings revealed a discrepancy of 34%. The reasons for this are discussed.

Adult↗

Enhancement of renal function with ornipressin in a patient with decompensated cirrhosis.

An infusion with Ornipressin (8-ornithin vasopressin) in a patient with decompensated alcoholic liver cirrhosis increased urinary volume from 30 ml/h to 500 ml/h, creatinine clearance from 24 to 65 ml/min, and fractional sodium excretion from 0.86% to 11.1%. Free water clearance decreased from -10.2 ml/h to -26.2 ml/h and noradrenaline plasma concentrations dropped from 2.04 to 1.37 ng/ml. After stopping Ornipressin infusion all values returned to initial concentrations. Possible effects are an increase of renal blood flow secondary to an increase in arterial blood pressure, possibly potentiated by the vasodilatory effect of the fall in noradrenaline and/or angiotensin concentration.

Adult↗

Post-heparin lipolytic activity in acute renal failure.

Total post-heparin lipolytic activity (PHLA), hepatic triglyceride lipase (HTGL) and protamine inactivated lipoprotein lipase (LPL) and plasma lipoprotein pattern were investigated in 8 patients with acute renal failure (ARF). PHLA was determined at 5, 10, 15, 30, 45 and 60 minutes after heparin administration (100 U/kg b.w.). Maximal PHLA in ARF was 6.12 +/- 1.56 mumol FFA/ml/h at 10 minutes versus 14.62 +/- 4.29 at 45 min in controls (= 42%, p less than 0.001). PHLA was reduced in ARF throughout the study period (p less than 0.001). Maximal HTGL activity (3.06 +/- 0.84 mumol FFA/ml/h) was obtained at 10 min in ARF versus 8.97 +/- 3.11 after 15 min in controls (= 34%, p less than 0.001). HTGL in ARF differed from controls at all points of determination (p less than 0.001). LPL maximum was 3.12 +/- 1.93 mumol FFA/ml/h at 15 min in ARF and 7.65 +/- 3.44 at 45 min in controls (= 40%, p less than 0.001). LPL activity was different from controls at 30, 45 and 60 min (p less than 0.001) but not at 5, 10 and 15 min after heparin injection. Due to a rapid decrease of LPL activity (half maximal activity after 34 min in ARF versus 94 min in controls, p less than 0.05) activity half life of PHLA was diminished in ARF (49 min in ARF versus 112 min in controls, p less than 0.01). Thus both the activity of HTGL and LPL is impaired in ARF. Because of the different activation kinetics of the two PHLA fractions no conclusions concerning maximal enzyme activities can be drawn from single determinations as suggested in previous studies on chronic renal failure.

Acute Kidney Injury↗