Is There a Difference Between a Safety Synthesis and a Diagnosis?

Is there any difference in your technique? Smaller, needles, smaller catheter, anything else that's different? Or you're pretty much doing it this way no matter what? I'm pretty much always going to use the safety synthesis. Can you have an effusion that is so small, it's hard to tap and yet could still be clinically significant? Or is it they kind of go together? If you can't get it, then it can't matter. They usually go together.