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Biomedical subjects

K H Weis

Publications and source records attributed to K H Weis.

At least 19 recordsLinked to original sources
PubMed1989

Suppression of neutrophil migration and chemiluminescence is due to the sulphur atom in the thiobarbiturate molecule.

In this study the hypothesis was tested that the substituent at the C 2 position of the barbiturate molecule is crucial for the obvious differences in inhibitory potencies between various barbiturates with respect to neutrophil functions in vitro. Using isolated neutrophils from healthy volunteers, the comparative effects of two pairs of sulphur or oxygen-substituted analogues on chemiluminescence, random and chemotactic migration were examined. Five other i.v. barbiturates were also tested in the chemiluminescence assay. The key observation with all the assay systems was that the oxybarbiturates proved ten to a hundredfold less suppressive than their sulphurated analogues or the other thiobarbiturates. Thus, enhanced inhibitory potency was dependent on the presence of the sulphur atom in the barbiturate molecule and could no longer be explained exclusively on the basis of divergent physicochemical features.

Chemotaxis, Leukocyte↗
PubMed1987

Alfentanil or fentanyl for anaesthetic procedures of two hours duration? A double-blind study.

Eighty women undergoing surgery of at least 2-h duration were randomly allocated to receive either alfentanil or fentanyl to supplement a diazepam nitrous oxide/oxygen anaesthetic. Anaesthesia was induced with fentanyl 0.2 mg and diazepam 10-20 mg and continued with nitrous oxide/oxygen. Analgesia was provided by injection of the narcotic using unlabelled ampoules that contained either alfentanil 0.5 mg ml-1 or fentanyl 0.05 mg ml-1. Apart from a marginally higher heart rate when alfentanil was used, there was no significant difference between groups at any time during the operation. Patients woke 2.7 +/- 3.1 min following discontinuation of nitrous oxide and were extubated after 10.3 +/- 7.6 min (alfentanil) and 17.3 +/- 19.0 min (fentanyl) (P = 0.1). However, following alfentanil significantly more patients could be extubated within 20 min to 30 min after completion of the operation (P less than 0.01). The last top-up dose of alfentanil had to be given nearer the end of the operation than the last dose of fentanyl (P less than 0.01). Patients receiving alfentanil needed significantly more (P less than 0.01) post-operative analgesia.

Adjuvants, Anesthesia↗
PubMed1987

[Is halothane obsolete? An illustration of measurement with two standards].

In 1986 the discussion on the further use of halothane broke out anew, especially after the Bristol symposium and the European Congress of Anesthesiology in Vienna. Everywhere there is great uncertainty on whether or not halothane should continue to be used. A critical analysis of the literature shows that there are two standards applied to halothane. When judged by the same stringent criteria as halothane other anesthetic techniques are also dubious, e.g. neuroleptanesthesia or epidural block. Finally, experience with isoflurane, the strongest rival of halothane, is not adequate to warrant abandoning halothane, especially as long as the question of coronary steal is still open. At present there is no solid scientific basis for vanishing halothane.

Anesthesia, General↗
PubMed1986

[Hemodynamic side effects of high-frequency jet ventilation as a function of lung volume. Impedance spirometric studies].

In five patients with acute respiratory insufficiency the changes in tracheal pressure (P), lung volume (V) and transthoracic electric impedance TEI (Z) were measured during delayed expiration all over the inspiratory capacity (IC) from TLC to FRC. The quasi-static V/Z- and Z/P-curves were two-dimensionally displayed, and the Z/P-curve was volume-calibrated on the Y-axis (Z) using the linear V/Z-relationship. During high-frequency jet ventilation (HFJV, 200/min), the Z- and P-excursions were displayed on the "frozen" Z/P-curve as flat discs. By well-aimed increase in driving pressure and I/E-ratio the unknown FRC was enhanced in 4 stages (I-IV) by 0.33 IC, 0.5 IC, 0.66 IC and 0.75 IC, to measure haemodynamic reactions 10 minutes later (Swan-Ganz catheter). The pulmonary vascular resistance remained unchanged between stage I and II. It changed moderately in stage III (+14%) and was found to be markedly increased in stage IV (+45%). The increase in PVR was well parabolically correlated (r = 0.88) to the fraction of IC by which FRC was expanded. In a previous study a very similar function could be documented by us for the end-inspiratory lung volume during conventional PEEP ventilation. Concomitant to the increase in PVR the CI fell linearilly (r = 0.95). We conclude from our results: 1. TEI may be of value in monitoring HFJV. It offers the possibility to measure the increase in lung volume ("PEEP effect") and to titrate it deliberately within the usable volume range IC. 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiography, Impedance↗
PubMed1985

[Etomidate versus methohexital for intravenous anesthesia with alfentanyl and nitrous oxide-oxygen. A double-blind study of circulatory behavior and postoperative course].

This study compared both etomidate and methohexitone for intravenous anaesthesia with alfentanil and nitrous oxide/oxygen in 2 X 20 patients scheduled for ENT-surgery, in a double blind, random fashion. Apart from the alternative use of etomidate and methohexitone the anaesthetic procedure did not differ: After a small dose of alfentanil anaesthesia was induced by a bolus dose of the hypnotic followed by a continuous infusion of the drug. In case of inadequate analgesia alfentanil was injected. This technique provided a good quality of anaesthesia and a remarkable cardiovascular stability. Critical arterial pressures or heart rates never occurred. During the operation patients receiving etomidate exhibited a moderate rise in blood pressure and a significantly lower heart rate than patients anaesthetised with methohexitone. After some 90 min of anaesthesia patients awoke on the average 7 min after the end of the operation and could be extubated at once. During the first three postoperative hours there was no difference in recovery between groups. Whereas half an hour postoperatively the capacity of immediate memory was limited to 44 bit following etomidate and 48 bit following methohexitone, i.e. to 47 and 54% of its normal capacity, there was only a minimum but significant impairment of cerebral function after 3 h. There was no difference in the need for alfentanil. The dosage of etomidate and methohexitone was lowe than that reported in the literature. It proved to be impossible for the anaesthetist to decide which drug he was using. Hence both anaesthetic techniques compare favourably with each other.

Adolescent↗
PubMed1977

[Hydroxy-ethyl-starch as plasma substitute in transurethral prostatectomy with the "cold-punch" method (author's transl)].

Each of 24 patients undergoing transurethral prostatectomy under spinal anaesthesia received 1000 ml HES and, depending from the clinical situation, some patients received blood-transfusion. Afterwards two groups were formed: group A (11 patients), who received HES only, and group B (13 Patients) with additional blood-transfusions. The following parameters were monitored simultaneously: blood pressure, heart rate, stroke index, cardiac output, active blood volume, hemoglobin and hematocrit in whole blood as well as in the irrigatin fluid of the bladder. They showed HES to be a useful plasma substitute for older patients. It is well tolerated and has a slow stabilising effect on circulation, which was effective for several hours. Furthermore, HES-infusion reduced the average need of bloodtransfusion by 500 ml.

Aged↗
PubMed1977

[Heart rate of anaesthesiologists under physical and psychological professional stress (author's transl)].

The heart rate of anaesthesiologists under defined physical and psychological stress as well as during normal anaesthetic practice was studied. An acceleration of heart rate during induction and management of anaesthesia did not occur except in the presence of complicating circumstances. A phone call or a beeper alarm led to a rather ergotropic heart rate reaction (increase of 21%), especially when sleep was interrupted (increase of 75%). Locomotion for a professional reason, whether urgent or not, enhanced the heart rate up to 121/min. A simultaneous subjective feeling of psychological stress had no additional effect. The heart rate during the treatment of life-threatening situations remained at 109/min and often exceeded that of exhaustive running. The mean heart rate during the normal narcotic programe (90/min) was not uncommon and comparable with that of other surgical disciplines. However an increasing tolerance was seen with growing experience. Physical and psychological stress during the anaesthesiologist's work could be differentiated by means of heart rate except in some single observations. In the presence of both stressing factors the heart rate seems to be determined by the motor effort required.

Adult↗
PubMed1977

[On the use of concentrated haptoglobin in the treatment of a haemolytic transfusion accident of the ABO-system (author's transl)].

The clinical course and the treatment of a case of severe haemolytic ABO-incompatibility are described. In addition to the routine therapy 3 times 2000 units of haptoglobinconcentrate were given since it is known according to the literature to metabolize free haemoglobin. The clinical result seems to confirm the beneficial effect. The course remained free of complications and the hospital stay was not prolonged. Further clinical experience is needed to confirm the effectiveness of the treatment with haptoglobin in cases with severe haemolysis.

ABO Blood-Group System↗