CPR（cardiopulmonary resuscitation (心肺复苏术) and first aid are related topics. It could be said that first aid is the more general of the two, and training in first aid might include instructions and practice on how to respond to a variety of medical emergencies that could be posing threat to life or to a part of a person's body. One such medical emergency could be cessation (停止) of breathing or heartbeat, and the appropriate response, in this case, might be to perform CPR. Thus, CPR can be seen as a type of first-aid response.
There can be differences in the amount of first-aid training people learn, and courses can sometimes be broken down into emergency and standard training. Standard training is actually the more extensive of the two, and would include teaching and learning how to handle a variety of medical situations like bites from insects or animals, broken bones, poisoning, childbirth, and care of wounds. Emergency first aid tends to be limited to the teaching of CPR, how to handle choking emergencies, and instruction on wound care for heavy bleeding.
CPR and first aid may be taught together or are sometimes taken as separate courses. People may need a whole day of practice or longer before getting CPR certification, which should be obtained from recognized agencies like the Red Cross. The big difference between CPR and first aid, in terms of taking classes, is that CPR focuses only on learning to perform cardiopulmonary resuscitation and recognize those circumstances as soon as possible in which it should be performed; while first-aid classes may teach this too, but they will teach in the broader context of how people need to respond to lots of different injuries or illness.
The issue of CPR and first aid may get confusing when people are asked to get training in one or both of these. Some people may be asked to take a first-aid course and have CPR training. Those who need more extensive training in standard first aid certainly won't satisfy this need by only taking a CPR course. Those confused about what training they need should get this issue clear with the person (usually an employer) requesting the training.
Being able to respond first in a medical emergency usually means needing to know CPR, but other knowledge could be just as essential. For instance, how to stop uncontrollable bleeding or how to handle an episode of anaphylactic shock (过敏性休克) could be vital too.
