Biomedical subjects

H Kreuscher

Publications and source records attributed to H Kreuscher.

At least 19 recordsLinked to original sources

PubMed1990

[Chemical compatibility of ketamine and midazolam in infusion solutions].

The chemical compatibilities of intravenous (i.v.) solutions containing ketamine and midazolam were investigated by UV/VIS spectroscopy, IR spectroscopy, and high-performance liquid chromatography (HPLC). The isotonic solutions used were NaCl 0.9%, fructose 5%, and glucose 5%. The concentrations of additives were 500 mg ketamine and 45 mg midazolam per liter i.v. solution. Comparison of the UV/VIS and IR spectroscopic measurements with spectra from the literature demonstrated, that the substances were pure, e.g. without larger impurities. The HPLC measurements were performed immediately after preparation of the solution and repeated after 6, 25, 50, 75 and 97 h. It was shown that there was no concentration decrease of ketamine and midazolam in the i.v. solutions within an experimental error of 1.5% and within 100 h. Reactions in the i.v. solutions with smaller than 1.5% conversion can not be excluded. We recommend that the prepared i.v. solution be used within 24 h.

Drug Combinations↗

PubMed1989

[The relief of postspinal headache using the Whitacre cannula. Experimental studies].

The structure of the spinal dura mater and the consequences of puncturing the dural tissue with different types of spinal needles were examined. There is no uniformly longitudinal parallel arrangement of dural fibers in human lumbar dura mater from the segments L3-5, but as shown in both scanning electron microscope imaging and polarized light microscopy the small collagenous fibrils are connected by cross-linked bridges. After perforation with Whitacre's pencil-point needle a kind of double layer membrane surrounds the puncture hole and might be responsible for the rearrangement of dural fibers and sealing of the hole after removal of the needle, like wings closing over each other (curtain-effect). This double layer membrane was not seen after dural puncture with sharp Quincke-bevelled needles.

Anesthesia, Spinal↗

PubMed1989

[The relief of postspinal headache using the Whitacre cannula. A clinical study].

In a prospective study spinal anesthesia was performed in 500 patients (338 male and 162 female patients between 16 and 91 years of age: mean 46 years), with a total number of 603 spinal anesthetics. In all cases a 22G Whitacre needle was used. All patients were mobilized from the day of the operation onward and visited 4 days later by the interviewer and asked about any symptoms, especially headache. Mild postspinal headache occurred in 11 cases (1.8% of total), all in patients younger than 50 years of age and more in women. There were 6 patients among the 11 who did not need specific therapy their headache; for the others antipyretic analgesics, adequate hydration and/or bedrest were satisfactory. The study shows that the incidence of postspinal headache was significantly reduced by the use of Whitacre's pencil-point needle in comparison with findings reported in the literature.

Adolescent↗

PubMed1989

[The physical compatibility of ketamine and diazepam in infusion solutions].

Physical compatibilities of infusion solutions containing ketamine and diazepam or midazolam in different concentrations were studied by visual examination and by light-scattering measurements. The isotonic infusion solutions used were fructose 5%, glucose 5%, and NaCl 0.9%. The concentration of additive were between 500 and 600 mg ketamine, 60 and 100 mg diazepam and 30 and 60 mg midazolam (Dormicum) per liter intravenous solution. During a period of 24 h the solutions remained colorless without demixing, precipitation, or changes in pH. The light-scattering measurements were performed immediately after preparation of the solution and repeated after 1, 4, 8, and 24 h using monochromatic light at a wavelength lambda 0 = 546 nm and temperatures T = 20 degrees and 37 degrees C. The light-scattering measurements showed that all intravenous solutions were physically true, homogeneous solutions with no change over a period of 24 h within experimental error, i.e. the solution behavior remained constant. A small amount of the dissolved particles (less than 0.5%) had diameters of 1-4 microns whereas those of all other particles were smaller than 0.02 microns. The particles with 1 to 4 microns diameter consisted of aggregates of the dissolved substances called microgels. Removal of both microgels and inorganic and organic dust is possible with filters of pore size 0.5 microns or by centrifugation at 10,000 rpm. In clinical practice filtering is much more feasible.

Diazepam↗

PubMed1989

[Proven safety of the Dräger circuit? Improvement of the absorber is desired].

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Anesthesia, Closed-Circuit↗

PubMed1976

Investigations of the sensory blockade effect of perineurally injected ethanol on the tail nerve of the mouse.

The effect of an alcohol block on the conduction of sensory stimuli in the tail nerve of the mouse was investigated using the perineural injection of solutions of ethanol (35, 40 and 45%). One hundred and fifty white mice of either sex were given 2 X 0.03 ml of the relevant alcohol solution into both sides of the tail. Before and after the injections repeated sensory conduction measurements were made using the rat tail method. Using 35% ethanol a temporary block of pain conduction could be achieved in both sexes. By increasing the concentration to 40 or 45%, a prolongation of the blocking effect and an increase in the accompanying increase of the pain threshold was observed in some animals. On the other hand, in some animals, temporary motor paralysis occurred following 35% ethanol, and this effect became more frequent and severe using 40 and 45% ethanol. A further increase in the alcohol concentration was not possible because of the occurrence of anatomical changes in the tails of the experimental animals.

Animals↗

PubMed1976

[Renal and circulatory function under ketamine anesthesia. An experimental study on animals (author's transl)].

Cardiac output, glomerular filtration rate, stroke volume, heart rate, and urinary output were determined in 10 mongrel dogs. Under the conditions of the experiment it was observed that in contrast to man cardiac and renal output as well as stroke volume declined significantly. Heart rate showed no significant change. With diminished urinary output a differential excretion of individual electrolytes was noted. To carry the results of these experiments over to humans is, in the author's view, not warranted unreservedly.

Anesthesia, Intravenous↗

PubMed1975