Most Swiss Guidelines recommend never to drain more than 1500ml of pleural fluid when performing a thoracocentesis. The reason is that excessive drainage might cause re-expansion pleural effusion (e.g. www.medstandards.ch). There is not much literature on the safe amount of fluid one can drain, but a clinical practice article on pleural effusions in the New England Journal of Medicine also states that "...in which case therapeutic thoracentesis to remove up to 1500 ml of fluid is indicated." (N Engl J Med 2002; 346:1971-1977).
Interestingly there is no evidence supporting this recommendation. Some data suggests that the risk of re-expansion pulmonary oedema might correlate with the baseline size of the effusion, rather than the volume of fluid removed.
However, the first results from research start giving us some answers and indicate that removing more than 1500ml of fluids is safe and feasible.
Ault M et al. (Thorax. 2015;70(2):127-132.) looked at 9320 patients during 11 years who underwent thoracocentesis and recorded the incidence of adverse events. They were able to show that:
Lentz RJ et al. (Lancet Respir Med. 2019;7(5):447-455.) showed that
All the details and lots of background information are very nicely summarized in this fabulous post on emcrit.org:
PulmCrit - Large volume thora: Can we drain 'em dry?
This is an excellent 5 min video on the proper use of a Linton tube in massive bleeding varices!
Doctors get thought many things that must be done in one sort of way and we do many things because we were thought so! Sometimes it is important though to question standard procedures especially as our knowledge grows rapidly over time.
It's only a couple of years ago many anaesthetists were thought to insert central lines 'blindly' by using anatomical landmarks. X-rays confirmed line placement, ideally in the lower part of the superior vena cava, and excluded complications like a pneumothorax. Line placement in the right atrium was said to cause cardiac perforation and accidental placement in the contralateral subclavian vein often led to re-insertions of new lines. But important questions remains: Is this all really true? What actually do we know?
PulmCrit.org looked into this issue and just posted an excellent little review. Their bottom line is:
Read their post here
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