[A microprocessor controlled device for long-term registration of motility parameters. Pressure, bowel sounds and occurrence in the gastrointestinal tract].
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Biomedical subjects
Publications and source records attributed to G Blümel.
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The concept of combined anaesthesia, the centrally-acting muscle relaxant guaifenesin (My 301) in a 5% solution with ketamine (and/or fentanyl) in addition to the inhalation of nitrous oxide and halothane is based upon the principle of "balanced anaesthesia". Guaifenesin amplifies the effect of several anaesthetics, which complement one another, allowing the dosage to be decreased and thereby reducing the cardiovascular stress. To induce anaesthesia, the combination of a cataleptic anaesthetic (ketamine = Ketanest, Ketolar) and a centrally acting skeletal muscle relaxant (guaifenesin = Myolaxin, My 301) is used. Because of the risk of aspiration the animal should be intubated as soon as possible. Anaesthesia will be prolonged by the carrier gas nitrous oxide (65%, weakly analgesic)/oxygen (65%), low concentrations of halothane (1.0 to 0.6 to 0.4%, weakly hypnotic and analgesic) and by a continuous drip infusion of 5% guaifenesin (relaxing, mild analgesic and sedative). The effect of all the other anaesthetics is increased by guaifenesin. To increase the analgesia and to control the cardiovascular parameters the additional injection of ketamine or fentanyl is recommended. The recovery period is short and the general condition is good both after a lengthy anaesthesia of 9 hours (n = 32) and after anaesthesia of 2 hours. No significant adverse effects on the cardiovascular system were detected.
Cell mediated immune reactions, demonstrated by leukocyte migration assay and histological analysis of spleen and lymph nodes, could be observed after fresh autografting of cortical segments in rats. The detected immune answer showed a bone-specific reaction pattern. In consideration of the temporal correlation of the observed immune reactions and the histological signs of graft incorporation, a connection of bone healing and immune system may be possible.
A detailed description of the technique of orotracheal intubation under visual control in rats is given. This method was used successfully in 190 animals, the complication rate being 3.2%. The hazards consisted of laryngospasm (1.6%) and fatal bleeding (0.5%). Intubation was proved to be a safe, reliable, simple and atraumatic way to establish a patent airway in this laboratory animal.
The use of pulse oximeters as a non-invasive, real time and online method for the continuous monitoring of oxygen saturation is discussed and compared to other methods like hemoreflectometry, and blood gas analysis. Analyses of linear regression show extraordinarily good correlations between all three monitoring systems. Pulse oximetry and hemoreflectometry on the one hand and blood gas analysis on the other hand sometimes show quite differing values of oxygen saturation. This phenomenon is due to the fact that the measuring methods are based on different working principles as well as it can be explained by the various hemoglobin-types. The pulse rate also measured by the pulse oximeter is nearly completely identical to the heart rate of the ECG. A slight temporal delay between the two acoustic signals is noticed and justified. Pulse oximetry seems to be superior to other oxygen monitoring systems because of its continuous noninvasive measuring technique.
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Etomidate and the closely related metomidate are known to inhibit cortisol synthesis. We studied the influence of metomidate on hemodynamic performance and survival time of bacteremic pigs. Thirty pigs, 30.2 +/- 0.8 kg, were anesthetized with intravenous metomidate (2.5 mg.kg-1.h-1) plus ketamine (3.0 mg.kg-1.h-1), and were then mechanically ventilated. The animals were randomly allocated to three groups of 10 pigs each. Group A received an infusion of live Pseudomonas aeruginosa bacteria (2.5.10(9).kg-1.h-1 organisms until death), Group B additionally received a bolus of 1 mg.kg-1 cortisol (followed by an infusion of 0.1 mg.kg-1.h-1) starting 1 h prior to the bacterial infusion, and Group C served as anesthesia control without receiving bacteria or cortisol. The experiments in Group C were terminated after 10 h. In Group A the cortisol level was severely suppressed from the very beginning. The animals died of circulatory failure after 4.3 +/- 0.4 h. In contrast, Group B exhibited fairly stable hemodynamics, but the animals died due to pulmonary edema after 11.1 +/- 1.3 h. Cortisol deficiency in metomidate anesthetized pigs facilitates the development of circulatory failure in the course of Pseudomonas bacteremia, which does not occur if cortisol is infused to reconstitute a physiological level. However, this cortisol substitution did not prevent the development of pulmonary edema caused by Pseudomonas aeruginosa. Possible mechanisms of the deleterious effect of cortisol deficiency and implications in regard to the clinical use of metomidate/etomidate are discussed.
A retrospective study of 20 surgical intensive care unit patients is reported. They were ventilated with continuous positive pressure ventilation (CPPV) and then switched to combined high frequency ventilation (CHFV). To find why there were variable responses to CHFV, the data of 20 patients were retrospectively evaluated with respect to respiratory index (RI), compliance (C) and extravascular lung water (EVLW). The results suggest that the indication line for CHFV was a C value greater than 45 ml/cmH2O and an EVLW value greater than 15 ml/kg BW.
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Live Pseudomonas aeruginosa (2.5.10(9).kg-1.h-1) were administered to awake (Group A, n = 10) and anesthetized piglets, which were given intravenous ketamine (Group K, 10 mg.kg-1.h-1, n = 8) or pentobarbital (Group P, 15 mg.kg-1.h-1, n = 8). The anesthetized animals were mechanically ventilated. In addition, a pentobarbital group (Group CP, n = 6) and a ketamine control group (Group CK, n = 6) were studied. The mean survival time was 10.5 +/- 3.0 h in Group A, 10.6 +/- 2.8 h in Group K, and 1.8 +/- 1.3 h in Group P. In Group P the arterial pressure, the cardiac output and the systemic vascular resistance declined soon after start of the bacterial infusion, whereas the pulmonary artery pressure increased. The animals died of irreversible circulatory failure. In Group K pronounced pulmonary hypertension and lethal pulmonary edema developed. There was no circulatory failure in Group A, but the animals also died of marked pulmonary edema. Groups CP and CK exhibited stable hemodynamics for a period of 8 h. The results of this study suggest a deleterious effect of pentobarbital on hemodynamics and survival time, and a minor suppressive action of ketamine on the circulation in septicemia. Therefore, data obtained from septic shock studies applying pentobarbital have to be evaluated carefully. Investigation of the effects of gram-negative bacteria or endotoxin should be performed in unanesthetized or, if anesthesia is necessary, in ketamine-anesthetized animals.
The so-called heparin level in the plasma of patients or healthy volunteers should be determined using only those methods which correspond to the test standard used by the producer of the heparin applied or which approach the corresponding test principle. The correlation of the ex vivo findings gained through biochemical and functional methods to the physiological effect is, as far as possible, only then guaranteed when methodical influences can be excluded. The data obtained through these test series do not, however, allow a transference to the physiological effect of the corresponding heparin preparations regarding anticoagulant as well as antithrombotic efficacy.
In numerous clinical studies, the antithrombotic effect and tolerance of low-molecular-weight heparins (LMWHs) were compared to those of unfractionated heparin (UFH). Based on our own experience and on a review of the literature the following conclusions can be drawn. In the field of prophylaxis of thromboembolism, including high-risk patients with major bone surgery, the antithrombotic efficacy of a single daily dose of LMWH is at least equivalent to two or three injections of UFH per day. It should, however, be noted that the margin between thromboembolic and bleeding complications has not become bigger, although this had been derived from experimental results. In order to avoid bleeding complications, it is absolutely necessary to take note of the manufacturers' recommendations. This is particularly important when a change of various preparations is considered, because the standardization of LMWH preparations is different and the units are not comparable. The main advantage of LMWH results from an improved practicability. The single daily dose leads to an improved compliance of patients and the nursing staff is spared a great deal of work.
The concept of balanced anaesthesia aims at an anaesthetic method for high risk patients by combination of different anaesthetic drugs. The anaesthetics and muscle-relaxants have to work in a way as to potentiate their effects and to reduce the side effects as well as the applied dosage. With this sensible regime the circulation and the metabolic energy should be less burdened. For the introduction of balanced anaesthesia, a combination of benzodiazepines (relaxing and sedative), morphine (analgetic and sedative) and quickly metabolizing hypnotics of the imidazol group (hypnotic and relaxing) is used. A fentanyl-drip-infusion continues and deepens the analgesia. After endotracheal intubation with the help of the carrier-gas nitrous oxide (weakly analgetic) and oxygen (2:1) a low concentration of volatile inhalation anaesthetics (weakly hypnotic) is added. Under artificial respiration low doses of competitive antidepolarizing neuromuscular blockers help to potentiate and reduce drug amounts of other anaesthetics especially of that for inhalation. At the end of balanced anaesthesia an antagonization of benzodiazepines, morphines and competitive neuromuscular blockers is recommended for emergency situations only because of possibly occurring changes of cardiovascular parameters.
After a median laparatomy, nephrostomy was performed on 22 porcine kidneys: puncture, dilatation and introduction of a 26-French operating sheath through the parenchyma into the renal pelvis. At the end of the operation, an 8-French nephrostomy catheter prepared with a collagen-fibrin tissue-adhesive sealant was introduced through the operating sheath and the sheath was afterwards extracted. The hemostasis in the nephrostomy tract was very good in all 22 cases. There were no complications such as wound infection or stone formation during a post-operative period of between one and 95 days. Experimental investigations showed severe bleeding in nontamponade of the nephrostomy tract, in tamponade with an 8-French nephrostomy catheter and in tamponade of the nephrostomy tract with the collagen fleece wrapped around an 8-French nephrostomy catheter but not coated with the fibrin glue.
In 26 patients percutaneous nephrolithotomy was carried out under local anesthesia with systemic sedation. Instead of the 25-French nephrostomy catheter used so far, a 5- or 10-French nephrostomy catheter prepared with a collagen-fibrin adhesive sealant was introduced into the nephrostomy tract. In all cases, excellent hemostasis was attained with the fibrin glue. In applying a fibrin glue, the danger of protracted venous or arterial hemorrhage from the parenchymal canal can be markedly reduced; the large-lumen nephrostomy catheter can also be dispensed with.
Various lymphocyte populations, dendritic cells and macrophages contribute to the intake of antigen. The transportation of antigen in the intestinal wall is possible with the help of receptive endocytosis, including extracellular protein in fluid droplets, bacterial and vegetable toxins, as well as certain viruses, which seem to be able to penetrate the cell membrane and enter directly into the cell. Own investigations: After endoscope controlled allergy-irritation of the gastro-intestinal tract, 20 people used in the clinical test showed acute signs of mucosal reaction with inflammation and swelling of the mucous membrane as well as haemorrhagic lesions. A histamine release from the mastcell was proved.