or an infection that's spread into your bloodstream,

即已经扩散到血液中的一种感染
one of the only ways to combat those infections effectively is to

有效对抗感染的仅有办法之一
introduce antibiotics directly into the bloodstream.

就是直接在血液中注射抗生素
Intravenous infusion is a similar mode,

静脉滴注是一个相似的方式
but now instead of a onetime injection,

但不像一次性注射那样
with an intravenous injection you have a syringe full of drug,

用一个装满药物的注射器以及一根针
a needle in the circulatory system,

将所有药物一次性地
and you introduce the drug all at once,

注射到血液循环系统中
in infusion you slowly pump the drug in

而是通过滴注缓慢地将药物注入人体
and you might be pumping it in continuously over a long period time,

药物滴注过程可能会持续相当长一段时间
maybe over hours or over days.

也许超过几小时或者几天
Sometimes this is done--you've seen on TV shows

有时是这样使用的在电视上你见过