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Biomedical subjects

B Landauer

Publications and source records attributed to B Landauer.

34 records · Page 2Linked to original sources
PubMed1977

[Influence of ventilatory pattern on the functional situation of the lung during inhalation anaesthesia. Part I: Spontaneous breathing versus IPPB (author's transl)].

After five hours breathing spontaneously enflurane, halothane and methoxyflurane only the rabbits under enflurane showed, apart from a mild respiratory acidosis, no deterioration of pulmonary functional situation. Halothane and methoxyflurane exhibited under the same conditions a significant worsening of elastic behaviour of the lung. The structural bases of the mechanical impairment were atelectasis, dystelectasis and interstitial edema. Postnarcotic examination of lung extracts in the wilhelmy balance showed no abnormalities in the spontaneously breathing animals. If one compares these findings, indicating an irritation of surfactant by halothane and methoxyflurane with the results after IPPB the conclusion can be made that under these circumstances IPPB represents an additional stress for the alveolar lining layer. From the theoretical point of view therefore it would be advisable in patients with surfactant deficiencies to avoid the combination of halothane or methoxyflurane with IPPB. The use of PEEP will be discussed in part II. The value of periodical sighs could not be established under our conditions. Longer periods of spontaneous breathing seem only advisable under halothane but not under enflurane or methoxyflurane because their respiratory depressant properties.

Acidosis, Respiratory↗
PubMed1977

[The significance of the ventilation pattern for the functional situation of the lung in inhalation anaesthesia. Part II: PEEP (author's transl)].

The present study demonstrates the beneficial effects of PEEP on the functional behavior of rabbit lungs after five hours anaesthesia with halothane and methoxyflurane. Instead of a highly significant decline of lung compliance as was seen after spontaneous breathing and IPPB, PEEP led to a constant though statistically non-significant rise of this criterion. Blood gas values, too, demonstrated clearly the superiority of this ventilatory pattern. In contrast to former investigations there were no histological findings indicating any structural damage to the lung. Postanaesthetic examinations of lung extracts in the Wilhelmy balance showed no deterioration after PEEP. From these experimental findings it is concluded that patients suffering from surfactant deficiencies will benefit from a moderate PEEP during anaesthesia with halothane or methoxyflurane.

Anesthesia, Inhalation↗
PubMed1977

[The influence of Halothane on surfactant activity of the lung (author's transl)].

Halothane, momentarily the most popular inhalation anaesthetic, was examined in respect of its surfactant irritating properties in 13 rabbits. After five hours IPPB-anaesthesia with this compound there was a highly significant fall of the compliance quotient (CQ), at the moment the most reliable criterion for the surfactant activity "in situ", from 3.34 to 2.76. Lung histology revealed patchy atelectasis, dystelectasis and interstitial edema. In contrast to this remarkable mechanical and structural deterioration, blood gas analyses showed a surprising stability of gas exchange, hinting a tremendous functional reserve. Postnarcotic examination of lung extracts in the Wilhelmy balance exhibited no persistent damage of the specific alveolar lining layer. On the basis of these experimental findings we recommend that halothane should not be used in patients with preexisting impairment of pulmonary surfactant system.

Animals↗
PubMed1976

[Old and new views on resuscitation].

The pro and contra of reanimation are discussed and the essentials of cardiopulmonary resuscitation are lined out according to the ABC of reanimation by Safar. The review of the literature shows that the majority of the therapeutic measures practised today is known already for over 200 years. A survey of the results of these live safing measures is given and the attitude and opinion of resuscitated patients are discussed.

Adult↗
PubMed1976

[New aspects of shock therapy with volume expanders (author's transl)].

For successful primary treatment of hemorrhagic shock the infusion of volume expanders is a ""conditio sine qua non''. Of the original possibilities for selection, Ringer's lactated injection can no longer be recommended for the compensation of intravascular loss in the light of more recent pathophysiological knowledge. Opposite to this, gelatin, dextran, hydroxyethyl starch, and albumin solutions are available as the mainstay of an adequate volume expansion. The danger of anaphylactoid side effects is to be estimated as about equal in all 4 groups of substances. Seen from the point of view of replacement function and of rheological and pharmacological properties, the higher molecular dextrans may still be considered the method of choice for shock therapy.

Dextrans↗
PubMed1976

[Dosage problems of sodium nitroprusside (author's transl)].

Sodium nitroprusside has proved a useful completion of anaesthesiologist's armament. Nevertheless there still exist some doubts concerning correct dosage. This uncertainity is aggravated by communications in literature about fatal outcomes of hypotensions induced with this drug. For the patient's safety, we recommend not to exceed an infusion rate of 15mcg/kg/minute or a total of 1.5-3mg/kg irrespective of the time of administration. In any case the development of metabolic acidosis or the occurence of tachyphylaxis or resistance should be a strong argument for discontinuing nitroprusside and changing to an other method of hypotensive anaesthesia. A useful aid is the control of infusion rate by the IVAC-531-machine.

Acidosis↗
PubMed1976

[Controlled hypotension with sodium nitroprusside (author's transl)].

Sodium notroprusside (Nipruss), in comparison with halothane and trimetaphan a very suitable hypotensive drug, was examined for blood pressure lowering efficency and possible side effects. For this purpose 7 patients (group 1) underwent "classical" hypotension during neurosurgical procedures. In 5 cases (group 2) nitroprusside infusion was needed for therapy of hypertensive crisis during vascular surgery. In all patients the hypotensive action was prompt and sufficient. Low blood pressure was accompanied by a 22.5% rise of heart rate and a 66% fall of central venous pressure. The development of mild metabolic acidosis seemed to be without clinical importance. The doses employed ranged from 3 to 13 (grpup 1) and from 1.5 to 3.1 gamma/kg/min (group 2). Sodium nitroprusside proved a very useful hypotensive drug, fitting well with the needs of modern anaesthesia.

Acidosis↗
PubMed1976

[Surfactants in amniotic fluids: a comparision between biomechanical and biochemical analyses (author's transl)].

44 specimens of amniotic fluid from the 25 week's gestation onwards were tested in a modified Wilhelmy-Langmuir surface balance. In addition percentage of lecithin in total phospholipids, total phospholipd phosphorus concentration and fatty acid composition of lecithin was determined. Lecithin, total phospholipid-phosphorus and palmitic acid show significant rises in concentration with gestational progress. The results of the surface tension measurements are significantly correlated with the biochemical analysis. Therefore, fetal lung maturity seems to be well estimated by the biomechanical method.

Amniotic Fluid↗
PubMed1976

[The influence of methoxyflurane (penthrane) on surface activity of the lung (author's transl)].

Methoxyflurane, at the moment the most potent inhalation anaesthetic, was examined in respect of its surfactant irritating properties in the rabbit. After a five hour anaesthesia with this compound there was, compared with a control group of animals which underwent only mechanical ventilation with room air for the same period, a significant decline of the compliance quotient from 2.99 to 2.55, indicating a relevant impairment of alveolar lining surfactant. A concomitant fall of arterial PaO2 from 84.8 to 71.3 mm Hg showed the resulting deterioration of respiratory function. Postanaesthetic preparations of these lungs examined using the Wilhelmy balance exhibited a significant fall of the stability index from 1.73 to 1.25, though hysteresis remained unaffected. Lung histology showed interstitial edema and patchy atelectasis, features which are found also in the early stages of post-traumatic pulmonary insufficiency. On this basis we recommend that methoxyflurane is not used in patients with impaired surfactant activity as such is found after severe traumatisation, head injury or in special preexisting pulmonary diseases. If this anesthetic is given to healthy individuals, the ventilatory pattern should include periodic sighs and prophylactic PEEP.

Animals↗
PubMed1975

[Anesthesia for ambulatory patients].

The specific problems of outpatient anesthesia are discussed with respect to the patient's condition, the anesthesist's qualification and pharmacological properties of anesthetics used. Methohexitone seems to be the best choice for induction. Problems may arise from the use of Propanidid, Ketamin and Diazepam. Nitrousoxide and Enflurane are a suitable completion. Endotracheal intubation, if needed, is facilitated by Suxamethonium, which is rapidly eliminated. Practical aspects of timing, premedication, induction, maintenance and ending of anesthesia are pointed out. After 1-2 hours the patient can be allowed to leave the hospital accompanied by a responsible person. Driving a car is not recommended before 24 hours have elapsed since anesthesia.

Ambulatory Care↗
PubMed1975

[The influence of enflurane (ethrane) on surface activity of the lung (author's transl)].

Enflurane (Ethrane), a new inhalation anesthetic, was examined for possible surfactant alterating properties. To elucidate this question two groups of rabbits underwent investigation: the first group (5 animals) was mechanically ventilated with room air over a five hour period. In the second group (7 animals) for the same period Enflurane in clinical dosages was added the inspired gas. At the end of the procedure in neither group could signs of impaired lung surface activity be detected: All rabbits showed normal blood gas values, normal pressure volume diagrams and physiologic behaviour of lung extracts in the wilhelmy balance. We conclude first that artificial ventilation "per se" does not harm lung surfactant and second that Enfluran anesthesia is a good choice for outstanding long procedures as well as for patients with already impaired surface activity of the lung, because there seems to be little risk of aggravating the situation.

Animals↗