As part of their standard usual clinical care, participants will undergo a diagnostic and/or therapeutic pleural intervention in the form of thoracocentesis or pleural aspiration; intercostal chest drain insertion; and/or talc pleurodesis. All of these procedures are invasive and associated with potential complications that participants will be informed about as part of standard informed consent procedures. These interventions will however be clinically indicated and carried out whether or not an individual chooses to participate in this study. For those individuals who do participate in the study, any complications of these standard clinical care procedures will be recorded as part of the data collection process for the study.