The
rapid obliteration of an empyema depends more on the maintenance of perfect
drainage than on any other factor. Lateral and frontal skiagrams should be
taken within 48 hours of surgical drainage. A fluid level in the empyema
indicates imperfect drainage ; this may be due to blockage of the tube by
fibrin ; in other cases the tube is too long and so projects above the bottom
of the cavity, but sometimes it is too short, so that the inner end has been
withdrawn from the cavity into the chest wall. In any of these circumstances,
the tube must receive immediate and appropriate adjustment.
The
length of the tube is subsequently controlled by frontal and lateral skiagrams,
taken after introducing 5 millilitres of iodized oil into the empyema through
the tube. The oil should be injected with the patient lying down ; the tube is
then occluded with a spigot and the skiagrams are taken with the patient in the
upright position. From these "sinograms" or "pleurograms",
which should be taken at intervals not exceeding 2 weeks, it is possible to
determine the relation of the inner end of the tube to the bottom of the cavity
(Fig. 13). The tube can then be adjusted so as to provide dependent drainage.
These films usually also show the size of the empyema. The tube must not be
removed until " sinograms " have shown that the empyema cavity has
been completely obliterated. This usually occurs 4-10 weeks after operation.
Large cavities and those drained after the optimal time require the longest
period of drainage. Patients who require prolonged drainage should be
encouraged to return to their employment with the tube still in position.
