Self rescue and rescuing others is a big part of our sport.  Every boater must be able to swim rapids, with and without gear.  Aid in rescues like bow rescues to the more advanced kayak roll are very common events on whitewater trips.  If someone is injured and requires medical attention, would you know what to so?  Do yourself and paddling buddies a favor, take CPR and First Aid in the off months.  When you feel very comfortable in solid class II water, consider taking the ACA Level 4 SWR class.