Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services for severe difficulty breathing, fainting, new confusion, heavy bleeding, coughing up more than a small streak of blood, or sudden severe chest pain.
Contact your surgical team promptly if you develop increasing redness, warmth, swelling, discharge, or opening of the wound.
Also seek advice for a fever, worsening breathlessness, pain not controlled by the prescribed plan, or repeated vomiting that prevents drinking.
Contact the team urgently if the drain comes out, disconnects, stops working, or suddenly collects much more blood or fluid.
Do not wait for a routine follow-up appointment for these symptoms.
The article also says
If you go home with a drain, follow the facility’s instructions.
Every sign above is quoted from the sofidex article on Open pleural biopsy. If you are not sure, err upward — it is always reasonable to be checked.