Air embolism complicating artificial pneumothorax: (Describing a new automatic pneumothorax appratus)

Abstract

Air embolism as a complication in pneumothorax is almost always avoidable. Since manometer control affords the surest means of safeguarding against gas embolism, pressure fluctuation during the filling is analysed and the conditions governing detection of needle closure discussed. A new pneumothorax apparatus is described which is based on these considerations, and which has the following features: All the cocks used in conventional types of pneumothorax apparatus are replaced in this new apparatus by one single multi-way cock. This cock has four different settings, one for each of the following operations; (a) Filling the apparatus with air; (b) blowing air into the pleural cavity; (c) measuring the pressure in the pleural cavity; (d) withdrawing air from the pleural cavity. This multi-way clock is operable with one hand, and, owing to its feelable marks, in the dark—i.e., without looking. One and the same manometer is kept coustantly in communication with the needle tube, whereby on the one hand the absolute pressure is measured, and on the other hand a closure of the needle passage is at once detected. Exceeding of a predetermined pressure limit is automatically indicated by a bell signal, so that there is no possibility of overlooking a needle closure. The size of the vessels used is the same as in the usual rigid types of apparatus, but there is double the quantity of air (1,000 c.c.) immediately available. On refilling the apparatus with air it is not necessary to clamp the needle tube. When the apparatus is set to the working positions the air-pumping device is permenently cut off from the rest of the apparatus, so that it is impossible for air to be forced into the pleural cavity directly from the pump or under the high pressure set up by the pump. By the braking action exerted upon the inflowing and outflowing air in the cock, with the aid of marks on the cock, the rate of air-flow can be very accurately regulated, while owing to the high internal friction in the cock the air flows out of the cock under low pressure but slightly influenced, practically speaking, by the actual head of water in the apparatus. Each filling is begun without any excess pressure, solely by virtue of the aspirating power of the pleural cavity. All the settings of the cock are clearly marked and named. On transition from any one setting of the cock to any other setting the manometer is automatically adjusted to zero. Only one limb of the manometer is visible, to avoid mistakes. The pressure limit at which the signal is to be given can be accurately set on a scale. The needle can be clamped in a needle holder so as to remain sterile. All glass parts are as far as possible enclosed, and are yet readily accessible for cleaning purposes through a door at the back of the apparatus.