pubmed.ncbi.nlm.nih.gov: Fatal air embolism in an extremely low birth weight infant: can it be caused by intravenous injections during resuscitation?
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Documents a fatal air embolism caused by air introduced via peripheral venous cannulas and syringes.
straightdope.com: Can air injected into the bloodstream really kill you? - The Straight Dope
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States explicitly that air injected into the bloodstream (air embolism) can definitely kill a person.