La Revue du praticien
-
La Revue du praticien · Nov 1990
[Current modalities of mechanical ventilation for acute respiratory failure in chronic respiratory insufficiency].
Acute respiratory failure in patients with chronic obstructive lung disease is a frequent and serious complication, with a mortality rate of 20 p. 100 and 57 p. 100 of the patients kept under mechanical ventilation for more than two weeks. The main problem with mechanical ventilation is an unavoidable intrinsic positive expiratory pressure and a hyperinflation that can be increased by the different modes of ventilation. ⋯ At the moment, there is no way of predicting the outcome of weaning in each individual subjects, and none of the various ventilation procedures has proved superior to the others. Nasal ventilation has recently been introduced in intensive care where it constitutes a major step forward being less invasive; it avoids intubation in 60 p. 100 of the patients but is more exacting for the physicians and nursing staff; finally, it makes it possible to treat acute respiratory failure at an earlier stage than previously.
-
Arterial concentration of CO2 (PaCO2) is dependent of pulmonary excretion. When this excretion is lower than cellular production respiratory acid-basis occurs: rise in PaCO2 which lowers pH and produces secondary increases in bicarbonate (HCO3-) plasma concentration. Respiratory alkalosis, generated by a CO2 pulmonary excretion greater than metabolic production is characterized by a fall in PaCO2 which raises pH and induces secondary reduction of plasmatic HCO3- concentration. Attention to the possibility of serious hypoxemia, cause or consequence, should always be regarded and treated in respiratory acid-base disorders.
-
The various techniques of cochlear implantation are described. Implants may be divided into mono- and multi-electrode and into intra- and extra-cochlear. Cochlear implants are indicated only in patients with total or deep bilateral deafness with residual fibres still functioning in the acoustic nerves. Intra-cochlear multi-electrode implants are the most sophisticated ones and usually provide better performances than those observed with mono-electrode implants.
-
Recent advances in epidemiology, virology and molecular biology have made it possible: 1) to isolate and characterize the hepatitis C and D viruses (and soon the virus of hepatitis E); 2) to develop vaccines against hepatitis A and recombinant vaccines against hepatitis B; and 3) to obtain a better understanding of the modes of transmission of the viruses and, consequently, to devise and offer an efficient prophylaxis.
-
Relations between endometriosis and infertility are complex and difficult to establish. Numerous theories have been suggested, but none of them has proved conclusive. As always in case of endometriosis, medical and surgical treatments are open to discussion. The right time for medically assisted procreation is obvious in patients with tubal obstruction but in the others it varies according to age, duration of infertility and previous treatments.