Back 2 my ? from yesterday. i have a vsd. was in hospital, regular iv in bend of left arm. nurse was not careful about air in line. how fast would symptoms of a air embolus show up?it's been 24 hours

Immediate: Air embolism is an immediate illness. Many iv's get small air bubbles that do not cause problems.

Quickly: Air embolism is dangerous to you. It takes a lot to cause cardiac trouble! but a small amount crossing can be harmful to brain. Most vsd flow is left to right and air will not cross even if substantial. Air to muscle, bowel etc may just be absorbed and asymptomatic. As a principle for you, ivs should be well flushed and filtered/air trap. Really for all! since asds may be unknown and more risk.

Generally right away: Because of the large pressure difference between the ventricles, there is very little risk of a "paradoxical embolus" or of clots or air going the wrong way (from right to left) across a vsd to produce a stroke or heart attack. That is generally a concern with atrial levels shunts like asds or pfos, but not something we worry about with vsds unless there is severe right ventricular hypertension.