Biomedical subjects

J Teichmann

Publications and source records attributed to J Teichmann.

At least 55 records · Page 3Linked to original sources

PubMed1979

[The effects of halothane-, nitroprusside- and trimethaphan-induced hypotension on cerebral blood flow and intracranial pressure (author's transl)].

Arterial hypotension to about 50 mm Hg mean pressure was induced in anaesthetized and artificially ventilated dogs by halothane, nitroprusside, and trimethaphan to study their effects on cerebral blood flow and intracranial pressure during hypotension. During nitroprusside induced hypotension there was a 32% increase in cerebral blood flow above control and a marked decrease in cerebral arteriovenous oxygen content difference indicating luxury perfusion of the brain. Cerebral blood flow remained high even 30 min after termination of hypotension. During halothane and trimethaphan hypotension cerebral blood flow remained unchanged. In all groups epidural pressure did not change substantially during hypotension but increased during recovery from nitroprusside hypotension by a maximum of 72% above control. It is concluded that during and after nitroprusside hypotension loss of cerebral autoregulation occurs which may result in a marked rise in intracranial pressure. Special vulnerability seems to exist shortly after termination of induced hypotension when arterial pressure begins to rise and brain perfusion follows a pressure-flow relationship.

Animals↗

PubMed1978

[Effects of isovolaemic haemodilution on pulmonary gas exchange and haemodynamics (author's transl)].

In experiments on 11 closed chest dogs the behaviour of pulmonary gas exchange and haemodynamics during isovolaemic haemodilution with 6% dextran was studied. The dogs were ventilated artificially (IPPB, PEEP = 0) with room air. After haemodilution a slight increase of arterial PO2 from 86 to 92 mm Hg was found. In another series of experiments an inspiratory O2-concentration of 25% was applied resulting in an increase of arterial PO2 from 106 to 113 mm Hg. In both series a decrease of alveolararterial PO2 gradients was observed. Effective pulmonary capillary blood flow varied in accordance with changes of cardiac output. Thus intrapulmonary shunt is supposed to have remained constant. The changes of pulmonary O2 diffusing capacity could be explained by the effect of haemodilution per se. At the end of the experiments ventilation was changed by adding a positive endexpiratory pressure of 8 cm H2O resulting in a decrease of arterial PO2 and a steep fall of cardiac output. In conclusion, isovolaemic haemodilution leads to only negligible variations of pulmonary gas exchange which should not be of any clinical importance.

Animals↗

PubMed1977

[Pulmonary gas exchange during isovolaemic haemodilution (author's transl)].

In experiments on 6 closed chest dogs the behaviour of pulmonary gas exchange during isovolaemic haemodilution with 6% dextran was studied. The dogs were ventilated artificially using an inspiratory gas mixture containing 25% O2. A slight increase of arterial Po2 values was found. This change was accompanied by a decrease in alveolar-arterial Po2 and Pco2 gradients. The size of effective pulmonary capillary blood flow varied in accordance with the size of cardiac output. The changes of pulmonary O2 diffusing capacity could be explained by the effect of haemodilution per se.

Animals↗

PubMed1975