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Biomedical subjects

A Grünert

Publications and source records attributed to A Grünert.

At least 19 recordsLinked to original sources
PubMed1992

Relationship between arterial and peripheral venous catecholamine plasma catecholamine concentrations during infusion of noradrenaline and adrenaline in healthy volunteers.

Noradrenaline and adrenaline were infused IV at 5 different rates (0.01-0.2 micrograms.kg.min-1) for 30 min to volunteers. The plasma catecholamine concentrations were determined by HPLC and electro-chemical detection. At the highest infusion rate, the arterial and venous plasma concentrations of noradrenaline increased from 1.18 to 44.1 nmol.l-1 and from 1.14 to 31.9 nmol.l-1, respectively, and of adrenaline from 0.29 to 23.9 nmol.l-1 and from 0.28 to 19.3 nmol.l-1, respectively. The peripheral venous plasma concentration of noradrenaline averaged 76% of the arterial concentration, and of adrenaline it was 73%. There was a linear relationship between the peripheral venous and arterial plasma noradrenaline and adrenaline concentrations at therapeutic doses.

Adult↗
PubMed1992

Plasma catecholamine concentrations after successful resuscitation in patients.

OBJECTIVES: To measure plasma catecholamine concentrations after cardiopulmonary resuscitation (CPR) and to correlate catecholamine concentrations with heart rate (HR), BP, and plasma glucose and lactate concentrations. DESIGN: Prospective, descriptive study. SETTING: Emergency medical service at a University Hospital. PATIENTS: Ten patients (58 to 85 yrs) with out-of-hospital cardiac arrest. INTERVENTIONS: At 1, 5, 15, 30, and 60 mins after restoration of spontaneous circulation, blood samples were drawn and BP and HR were measured. Plasma catecholamine concentrations were measured by high-pressure liquid chromatography and plasma glucose and lactate concentrations were measured by enzymatic methods. MAIN RESULTS: Median plasma epinephrine and norepinephrine concentrations were 136.3 micrograms/L (136,300 pg/mL), range 27.6 to 397.6 micrograms/L (27,600 to 397,600 pg/mL), and 4.7 micrograms/L (4700 pg/mL), range 1.8 to 14.5 micrograms/L (1800 to 14,500 pg/mL), respectively, at 1 min. Median plasma epinephrine and norepinephrine concentrations decreased to 8.7 micrograms/L (8700 pg/mL), range 1.2 to 55.0 micrograms/L (1200 to 55,000 pg/mL) and 1.9 micrograms/L (1900 pg/mL), range 1.3 to 5.8 micrograms/L (1300 to 5800 pg/mL), respectively, at 60 mins after restoration of spontaneous circulation. Epinephrine concentrations decayed with a semilogarithmic decay pattern. The half-life for the alpha phase was 2.2 mins and was 38.7 mins for the beta phase. Mean values of systolic arterial pressure were between 136 +/- 23 mm Hg at 1 min and 120 +/- 15 mm Hg at 30 mins. Median plasma glucose concentrations were between 8.2 mmol/L (147.7 mg/dL; range 5.8 to 11.2 mmol/L [104.5 to 201.8 mg/dL]) at 1 min and 13.9 mmol/L (250.4 mg/dL; range 9.7 to 16.6 mmol/L [174.8 to 299.1 mg/dL]) at 30 mins. Lactate values were between 11.4 mmol/L (range 4.7 to 16.5) at 1 min and 5.2 mmol/L (range 2.7 to 12.5) at 60 mins. No significant correlations were found between circulating catecholamine concentrations and the other variables. CONCLUSIONS: After CPR, plasma catecholamine concentrations remained at high values but they did not lead to increases in BP, HR, or circulating glucose concentrations.

Aged↗
PubMed1992

Relationship between infusion rates, plasma concentrations, and cardiovascular and metabolic effects during the infusion of norepinephrine in healthy volunteers.

OBJECTIVE: To determine the relationship between iv infusion rate, plasma concentrations, and hemodynamic and metabolic actions of norepinephrine. DESIGN: Norepinephrine was administered by using five iv infusion rates (0.01 to 0.2 micrograms/kg/min) for 30 mins each to eight volunteers, for the purpose of constructing cumulative plasma concentration-response curves. SETTING: Laboratory of the Department of Anesthesiology at a university hospital. MEASUREMENTS AND MAIN RESULTS: Systolic and diastolic BP, heart rate, and the plasma concentrations of norepinephrine, glucose, nonesterified fatty acids, and insulin were measured at the end of each infusion rate. During the highest infusion rate, plasma norepinephrine concentrations increased from 199 +/- 75 to 7475 +/- 1071 pg/mL (1.18 +/- 0.44 to 44.18 +/- 6.33 nmol/L). Typical hemodynamic responses, such as increases in BP and decreases in heart rate, were seen, while the plasma concentrations of glucose and nonesterified fatty acids increased from 92 +/- 10 to 132 +/- 17 mg/dL (5.1 +/- 0.6 to 7.3 +/- 0.9 mmol/L) and 11 +/- 4 to 34 +/- 6 mg/dL (0.11 +/- 0.04 to 0.34 +/- 0.06 g/L), respectively, during the 0.2 micrograms/kg/min infusion rate (p less than .05). Despite the increase in glucose concentration, insulin remained at baseline values. Metabolic and hemodynamic effects occurred at similar plasma concentrations throughout the study. CONCLUSIONS: Administration of norepinephrine showed no selective hemodynamic actions. The metabolic responses observed in this investigation were similar to those responses seen during increased endogenous sympathetic nervous system activity, such as stress, exercise, or trauma.

Adult↗
PubMed1992

Measurement of mucociliary transport velocity in ventilated patients. Short-term effect of general anesthesia on mucociliary transport.

OBJECTIVES: The objectives of this study were to evaluate a method for measuring BTV in ventilated patients and to study the short-term effect of general anesthesia with midazolam, Fentanyl, pancuronium and O2:N2O on BTV. DESIGN: The study included phantom measurements on a bronchoscopy model and the determination of BTV in patients in a convenience sample trial. SETTING: The study took place in a university hospital. PATIENTS: Fourteen patients undergoing major abdominal surgery with planned postoperative mechanical ventilation were included in the study. All patients gave their written informed consent to participate in the study. INTERVENTIONS: Bronchial mucus transport velocity was measured with a small volume (0.05 to 0.08 ml) of technetium 99m-labeled albumin microspheres with an activity of 3 MBq. The radiolabeled bolus was deposited on the dorsal mucosal surface at the distal end of the right and left main bronchus via flexible bronchoscopy. The movement of the microspheres toward the trachea was visualized and recorded using a scintillation camera; quantitative evaluation utilized the condensed image. MAIN MEASUREMENTS AND RESULTS: The technique was validated in a bronchoscopy model and in an intubated patient by moving a radioactive drop in a catheter through the main bronchi at velocities from 0 to 20 mm/min. The velocities determined by the image processing technique correlated well with the data by the model and patient determination (right bronchus, r = 1.0; left bronchus, r = 1.0). In seven ventilated patients, mechanical irritation by the fiberscope produced no significant effect on BTV. The BTV was measured preoperatively in seven conscious patients one day before surgery while they received local anesthesia with 10 ml of 1 percent lidocaine and postoperatively while they received intubation anesthesia. The preoperative and postoperative BTV values showed no significant differences (10.5; 5.7 to 13.7 mm/min; vs 9.7 (3.7 to 15.3) (median with range). CONCLUSION: By this method, bronchial transport velocity can be determined in a relatively short time in ventilated patients. General anesthesia with midazolam, Fentanyl, pancuronium and O2:N2O does not influence BTV.

Adult↗
PubMed1992

Adrenaline: relationship between infusion rate, plasma concentration, metabolic and haemodynamic effects in volunteers.

The present study investigated the relationship between supraphysiological plasma concentrations of adrenaline and the resulting haemodynamic and metabolic effects. Adrenaline was administered at five infusion rates (0.01-0.2 micrograms kg-1 min-1) in an escalating sequence to eight volunteers. The arterial plasma concentration of adrenaline increased from 53 +/- 44 to 4349 +/- 818 ng litre-1 during the highest infusion rate. Typical haemodynamic responses, such as increase in blood pressure and heart rate, were seen. The plasma concentrations of glucose and lactate increased from 5.2 +/- 0.4 to 13.7 +/- 1.3 mmol litre-1 and from 0.9 +/- 0.3 to 4.7 +/- 2.6 mmol litre-1, respectively, during the highest infusion rate without a significant increase in insulin concentration. Non-esterified fatty acids increased from 379 +/- 97 to 1114 +/- 331 mumol litre-1 during the 0.06 microgram kg-1 min-1 infusion rate. Adrenaline had no selective haemodynamic effect. If similar metabolic effects occur in patients during treatment with adrenaline or other sympathomimetics, they may further increase breakdown of energy stores in a situation of increased catabolism, and impair utilization of parenteral nutrition.

Adult↗
PubMed1991

The consequences of continuous haemofiltration on lung mechanics and extravascular lung water in a porcine endotoxic shock model.

Endotoxinaemia (E. coli endotoxin, 0.111.B4) and pulmonary hypertension were evoked in 20 swine, randomly assigned to receive either zero-balanced venovenous haemofiltration (HF) with an ultrafiltration and replacement rate of 600 ml/h (HF group, n = 10) or to undergo an uninfluenced spontaneous course (E group, n = 10) during a constant infusion of endotoxin until the end of the experiment. Endotoxin-induced pulmonary dysfunction was assessed on the basis of extravascular lung water (EVLW) using a thermo-dye technique via a fiberoptic intra-aortic probe, gas exchange and lung mechanics, the latter derived by a pressure-volume loop (P/V loop) of the respiratory system (super syringe, flow 30 ml/s, tidal volume 600 ml). A comparable increase in alveolo-arterial oxygen difference and a constant EVLW was observed in both groups. The progressive deterioration of hysteresis area and compliance parameters by endotoxinaemia was significantly blunted by HF. Independent of an impact on pulmonary oedema zero-balanced HF modifies endotoxin induced lung injury, probably by the convective transport of mediator substances.

Animals↗
PubMed1990

Influence of continuous haemofiltration on haemodynamics and central blood volume in experimental endotoxic shock.

In order to assess the influence of continuous haemofiltration (HF) on haemodynamics and central blood volume in endotoxic shock, endotoxinaemia was invoked in 20 swine (28-32 kg). 15 min after doubling the mean pulmonary pressure, the animals were randomly assigned to receive either a zero-balanced veno-venous HF with an ultrafiltration and replacement rate of 600 ml/h (HF group, n = 10) or to observe the spontaneous course (E group, n = 10) under a constant infusion of endotoxin for 4 h. A trend to a higher survival rate in the HF group (6/10 vs. 3/10; E group) during the observation period was evident, but not statistically significant. Early initiation of HF during endotoxic shock modifies the haemodynamic response, lowering the pulmonary artery pressure (PAP), PCWP, pulmonary (PVR) and systemic vascular resistance (SVR), compared to the spontaneous course, whereas the decrement of central blood volume was comparable in both groups. These changes cannot be explained by effects of the HF on the volume status, but supports and additional effect by the filtration of small and medium-sized molecules.

Animals↗
PubMed1990

The role of alpha 1-adrenoceptors in adrenaline-induced hyperkalaemia.

The hyperkalaemic action of adrenaline was investigated in 44 anaesthetized domestic pigs. Plasma and epicardial concentrations of K+ were measured, in the latter case with an ion-selective electrode. Adrenaline 10 micrograms kg-1 caused a rapid increase in the plasma concentration of K+ from 4.2 to 5.9 mmol litre-1. The magnitude and the time course of epicardial concentration of K+ were similar. Alpha-adrenoceptor block with either phentolamine 5 mg kg-1 (non-selective block) or prazosin 0.1 mg kg-1 (selective alpha 1-adrenoceptor block) abolished the hyperkalaemic effect of adrenaline in the plasma and on the epicardium. The alpha 1-adrenoceptor agonist phenylephrine increased the K+ concentration, but the alpha 2-adrenoceptor agonist UK 14.304 did not cause any change in concentration. These results suggest that the hyperkalaemia induced by adrenaline occurs in the interstitial fluid of the myocardium and is mediated by alpha 1-adrenoceptors. These findings may be important in patients at risk of hyperkalaemia, with implications, for example, in the use of suxamethonium during induction of anaesthesia.

Adrenergic alpha-Agonists↗
PubMed1990

Anti-lipopolysaccharide-immunoglobulin (IgG-anti-LPS) therapy in intensive care patients following surgery from infectious disease.

In 18 intensive care patients the effect of a IgG-Anti-Lipopolysaccharide (Anti-LPS), was investigated in a randomized study following surgery after bacterial infections, mostly peritonitis. Fresh frozen plasma was administered during the first 5 postoperative days, containing either more than 65 micrograms/ml Anti-LPS in the therapy group or less than 12.5 micrograms/ml in the control group. The serum level of Anti-LPS was monitored. Clinical and chemical parameters were recorded to evaluate infectious complications and outcome of the patients. The mortality in the treatment group was not different from the control group with 30% (3 out of 10) and 25% (2 out of 8), respectively. No beneficial effect was observed either from the administration of Anti-LPS or from endogenously produced Anti-LPS on any clinical parameter in our patients.

Adult↗
PubMed1990

[Comparative studies of administration of xylitol or glucose in parenteral infusion of amino acids in critical care patients].

In a prospective, randomized study, two different concepts of carbohydrate application in the postoperative state were investigated and statistically analyzed in 20 intensive care patients in each group. Aim of the study was to evaluate influences of glucose or xylitol infusions in critically ill patients. Under the strict control of prerequisites for the application of parenteral nutrition in general and the application of specific substrates specifically, the study is based on the hypothesis that adverse reactions of the substrates like hyperglycemia should not occur. As a main result of the study, statistical significances of differences between the two groups could not be substantiated. The only difference between the two groups of severely ill patients with ventilation and hemodynamic support was an instability in glucose concentrations in blood under the application of glucose. Some patients in that group showed an increase in glucose concentration, which made insulin therapy necessary. We conclude that glucose is also applicable under the marked hormonally fixed conditions of postoperative metabolism if a narrow control of glucose is performed with an interruption of glucose application when concentrations increase. Also, on the basis of our data, xylitol showed a higher degree of security because under application of this substrate changes of glucose did not occur. In all cases where physiological conditions are achieved, glucose is the first choice of carbohydrates. In all those cases where the possibility exists that behind a normalized glucose concentration alterations of metabolism may be hidden, the application of xylitol offers the possibility to avoid imbalances and substrate load.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1990

[The bowel as an ischemic organ].

Due to the progress that has been made in intensive care, more and more patients survive shock. It is a clinical observation that their condition improves substantially with the restoration of intestinal function. Different experimental models have been developed to investigate the pathophysiology of the intestine in shock. As noxious periods, both the phase of ischemia and the phase of reperfusion have been identified. Since the experimental models are methodologically very different, the results of the various studies may only be compared with reservations. Nevertheless, it can be stated that reduced intestinal blood flow leads to ischemia and hypoxia of the villous tips. Reperfusion may lead to further mucosal injury. During this period oxygen free radicals and their derivates seem to play an essential role. Xanthine oxidase is thought to be the major source of these radicals in the small intestine. During ischemia ATP is catabolized to hypoxanthine, which is enzymatically transformed to xanthine, a process generating oxygen free radicals. Moreover oxygen free radicals seem to be produced by activated neutrophilic granulocytes. At present, only hypotheses exist concerning the interactions between granulocytes and these radicals. The mechanism of injury produced by oxygen free radicals is based on the peroxidation of the lipid components of the cellular membrane system. The small intestine represents a very vulnerable shock organ: apart from its very important nutritive functions, it provides the necessary barrier between the intestinal pool of endotoxin and the circulation. The loss of these vital functions due to ischemic lesions dramatically worsens the chances for the patient to survive. Therefore, it is necessary to develop therapeutic principles to maintain or restore intestinal function in shock.

Free Radicals↗
PubMed1989

[The foundation of clinical nutritional therapy and the use of amino acid solutions].

The high value of clinical nutrition as an important component in polypragmatic therapy of severely ill patients with increasing age and restricted compensatory capacity is today unquestioned. The areas of interest and applications have reached a high degree of complexity by many differentiations. The metabolic interrelations under pathological conditions influence especially the application of amino acids. By the enormously increased standards of analytical procedures and instruments huge amounts of data have been gathered but methods and tools for interpreting the complex analytical results have not been developed to the same degree. Considering physiological, pathological biochemical, and biophysical alterations, this review discusses application of amino acids, evaluation and interpretation procedures, as well as indications, contraindications, and effective monitoring. The important regulatory function of the liver in connection with the urea production rate, and the physiological pattern and concentrations of amino acids in plasma are both discussed in detail. Also discussed is the therapeutic advantage of determining total concentration and relative composition of the amino acid pool in plasma, especially in severely ill patients.

Amino Acids↗