We intend to combine the old and new in an observational study comparing findings on thoracic ultrasonography and pleural manometry during thoracocentesis with patient-reported symptoms and the key clinical outcomes of presence of un-expandable lung and success of talc pleurodesis. The investigators hypothesise that the previously described variations in pleural elastance can be correlated with appearances and anatomical changes visualised on thoracic ultrasonography; and in combination can be reliably utilised to predict clinical outcome. The study may allow the proposal of a treatment algorithm that allows patients with pleural effusion to be managed in a more expeditious and efficient manner.