1. Factors which affect fluid accumulation within the pleural
cavities have been discussed, particular emphasis being laid on
the derangement in the handling of protein which may occur at serous surfaces.2. A method of e- timating albumin turnover in serous effusions
has been described.3. Forty -two patients, whose diagnoses had been established,
were included in the investigation. The evidence for the
diagnosis in each case has been presented in detail and a clinical report on each patient has been given in .Appendix A.4. The diagnostic groups examined were; tuberculosis,
pulmonary embolus, lung carcinoma, secondary carcinoma and
congestive cardiac failure. In each group the rate of albumin
entry into, and loss from, the pleural cavity has been estimated and the results expressed individually and collectively.
These have shown that the rate of albumin loss tended to use low
in all conditions other than pulmonary embolism. In pulmonary
embolism, where no significant reduction in this value is
thought to exist, the rate of albumin loss bore a direct
relationship to effusion volume.In some instances, the change in the albumin turnover
pattern following intrapleural prednisolone administration was
also measured. These results have been expressed in grams
albumin entering or leaving the pleural cavity in 24 hours.
The mean results of each group have also been expressed in
mg./kg./hour albumin and the "effusion fluid" loss in
ml./kg./hour. The rate of albumin entry has been found to fall
fairly consistently following prednisolone administration.The response in the rate of albumin loss has been more variable
and this has been attributed to three factors:(1) the volume of the effusion,
(2) the degree of reversibility of any inflammatory condition
of the parietal pleura, if present,
(3) a corticosteroid affect in reducing lymphatic capillary
permeability.5. x patient with malignant granulosa cell tumour of the ovary
associated with ascites and a right pleural effusion has also
been investigated. The results, which are thought to apply to
Meigs' syndrome, demonstrated that a very large amount of
albumin was leaking into,he ascites and some of this en route to
the blood vascular system spilled into the right pleural cavity presumably
from either the diaphragmatic or mediastinal
lymphatics.6. The known pathology of the various conditions, as it is
likely to affect the pleural space, has been reviewed and the
results of the investigations correlated with it.7. It has been suggested that there is a diagnostic application of the method when routine clinical, bacteriological,
biochemical and histological investigations have failed to secure the diagnosis.8. The method has been shown to be particularly applicable to
a study of the importance of certain capillary permeability
factors in diseases associated with ascites and pleural
effucion.9. Finally, in u light of the findings, the present nomen- clature of pleural effusions has been discussed and certain
recommendations made regarding the definition of the terms
"exudate" and "transudate "
