Biomedical subjects

N Hackstein

Publications and source records attributed to N Hackstein.

4 recordsLinked to original sources

PubMed2000

Frequency of pancreatitis after endoscopic retrograde cholangiopancreatography with iopromid or iotrolan: a randomized trial.

Blood isotone contrast media is considered to be less toxic to vascular and pancreatic duct endothelium than high-osmolar contrast media. In this study we assessed the impact of a low-osmolar contrast agent compared with a blood isotone product on pancreatic damage induced by endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic retrograde sphincterotomy (EST). In a prospective trial 42 consecutive ERCP/EST patients were randomized to receive either iopromid, a low-osmolar non-ionic contrast agent (770 mosmol/kg H2O), or iotrolan, a blood-isotone non-ionic product (320 mosmol/kg H2O). The endoscopies were performed by two experienced endoscopists. Forty patients were included in the study. Blood samples were collected before and 40 min, 2, 4, 6 and 24 h after the endoscopic procedure. Samples were analysed for pancreatic serum enzymes, acute-phase proteins and blood counts. A clinical pain score was investigated. Post-ERCP pancreatitis was diagnosed in 2 patients in the iopromid group and in 5 patients in the iotrolan group. There was no significant difference between groups in the time course of pancreatic serum enzymes, acute-phase proteins or in the pain score. Due to the small number of patients in this study, only stronger differences caused by the two contrast media could have led to statistically significant results. We did not observe statistically significant differences in comparing iotrolan and iopromid concerning ERCP/EST-induced pancreatic damage.

Adult↗

PubMed1999

[Calculation of renal clearance by dynamic measurement of excreted activity].

AIM: In this paper we present a new method to measure the renal slope-clearance of Tc-99m-MAG-3 in a single-shot model (Excretion-clearance). METHODS: A renal scintigraphy with Tc-99m-MAG-3 was performed in 22 patients. The excreted activity of the tracer in the kidneys and the bladder was dynamically measured using a double-head gamma-camera. Additionally the total absorption over the kidneys and the bladder was determined. The Excretion-clearance was calculated in a differential and an integral variant. Simultaneously the 2-compartment-clearance (Sapirstein-clearance), the Oberhausen-clearance and the Bubeck-clearance were calculated. RESULTS: The Sapirstein-clearance is considered as the "gold standard" in a single-shot model. The correlation of the Bubeck-clearance and the Oberhausen-clearance ranged from r = 0.96 to r = 0.97, the Excretion-clearance (differential-method) correlated with r = 0.90. The absolute difference of the clearance-values was lowest comparing the Bubeck-clearance with the Sapirstein-clearance with an average difference of 11%, whereas the Excretion-clearance revealed at least an average difference of 21% and the Oberhausen-clearance of 24%. DISCUSSION: The Excretion-clearance requires a more complicated protocol measuring the clearance in comparison to the Bubeck-clearance. The results of the excretion-clearance differ more from the Sapirstein-clearance with regard to the examined patient population than the Bubeck-clearance. Regarding the theoretical basis of the methods, we expect advantages of the Excretion-clearance compared with the Bubeck-Clearance in patients with compartmental disproportion or with a low clearance. We are going to prove this in combination with the above mentioned methodical improvements in a further study.

Adult↗

PubMed1994

[ECG forward simulation with the PC].

This paper describes a simulation program for ECG modelling for use with IBM-compatible computers. The underlying three-dimensional heart model comprising 4,500 units complies with the four criteria for valid ECG-forward modelling established by Gulrajani in 1989: accurate cardiac geometry, element-to-element propagation of the excitation stimulus, definition of action potentials and a suitable means of computing the surface ECG potentials from those measured in the model. For evaluation of the model, simulations of physiological excitation and of pathologies (Wolff-Parkinson-White syndrome, complete AV-block, inferior wall ischaemia) were examined. A high level of correspondence was found between the model situation and the surface ECG. In view of the widespread use of IBM-compatible computers, this new program is well suited for teaching and training purposes.

Arrhythmias, Cardiac↗

PubMed1990

Diagnostic value of electrocardiographic variables to predict the presence of ventricular late potentials.

To test the hypothesis that the presence of ventricular late potentials in the highly amplified, averaged and filtered surface electrocardiogram (ECG) can be predicted from the conventional surface ECG, 211 patients with and without previously documented sustained ventricular tachycardia outside the acute phase of myocardial infarction were studied. The presence of left ventricular akinesia or aneurysm was significantly correlated with the ECG score (based on Q wave duration, R wave duration and amplitude ratio). The mean ECG score in patients without ventricular tachycardia was 3.4 +/- 3.5 points compared with 5.5 +/- 3.9 points (p less than 0.001) in patients with ventricular tachycardia. The presence of late potentials was positively correlated with the ECG score in the whole cohort of patients. This was also the case in the subgroup of patients without a history of sustained ventricular tachycardia. In contrast, in patients with ventricular tachycardia, the presence of late potentials was independent of their ECG score. Using linear discriminant function analyses to predict the presence of late potentials, a history of ventricular tachycardia alone and the ECG score alone had a high predictive power (high standardized coefficients). If combinations of variables were analyzed including estimates of left ventricular function (presence of aneurysm or akinesia; ejection fraction), the ECG score and a history of ventricular tachycardia still ranked highest. The influence of ejection fraction if used in combination with other variables for the prediction of late potentials was relatively small (standardized coefficient of 0.4). In conclusion, the surface ECG can be used in patients previously free of sustained ventricular tachycardia to predict the presence of ventricular late potentials.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrocardiography↗