The rate of fluid accumulation can influence whether an effusion causes tamponade.

This statement is **true**. The material explains that pressure rises slowly for small increments of fluid, then rises rapidly after a critical level is reached. It also notes that a litre or more may sometimes accumulate gradually without tamponade. These observations show why volume alone does not determine the haemodynamic effect; the pace of accumulation and the pressure response matter. **Key takeaway:** The clinical effect of an effusion depends on how fluid accumulates as well as how much is present. **Glossary:** **Effusion**: excess fluid in a body space. **Tamponade**: impaired cardiac filling caused by raised pericardial pressure.