、。
Hey, there's no pulse.
Literal
Hey, pulse [subject-が] doesn't-exist [assertive-ぞ].
A dramatic line, probably from a medical/emergency scene. おい is a rough-edged masculine vocative 'hey, you.' The final ぞ is an emphatic masculine sentence-ender that asserts or announces — stronger and blunter than よ, marking this as urgent or serious news. 脈がない combines the existence verb ない with が: 'there is no pulse.'