Basic first aid (terror situation)

 In today's risky world first aid knowledge could come in handy, so here's a few basic tips.

First and most important tip!  Do not become a casualty yourself, don't put yourself in harms way to help someone else, yes it sounds callous, but having you as an extra casualty isn't going to help the next first aider who comes along, and you won't be able to help the casualty who was there in the first place

Second step phone for help, never assume someone else has done it, it doesn't matter if twenty people phone, better than no bugger phoning for help.
Tell the emergency service the location, and basic details of the incident, and number of casualties if you know.  If there's a shooter still there tell them that and how many if you know, also what weapons are being used, rifle, pistol or knife etc, this helps them send the proper response.

Now the first aid part

Check the quiet casualties first, the ones shouting and screaming are alive and breathing, the quiet ones may not be.

 ABC. Yes it's that easy, A is for Airway.  B is for Breathing. C is for circulation.

A check the casualty has an airway open, tilt the head back and lift the chin.

B once the airway is open, bend down put your ear by the casualties mouth and listen for breathing, and look for the chest rising and falling. If they are not breathing you'll need to do "rescue breaths" (mouth to mouth)

C Now check for circulation, if you know how to check the pulse check that, if not look for other signs, like blue lips, lack of capillary refill.  If there's no pulse you'll need to do chest compressions as well (full CPR)  the official guidelines are two breaths to thirty compressions, the compressions to the rhythm of the song staying alive.

To be honest it's much better if you learn how to do these properly, there's plenty of courses around, many basic ones free.

Now the serious stuff. 

If there's a knife or big piece of shrapnel sticking in someone, leave it there, it's plugging the wound.

Puncture wounds to the chest, if it's bubbling you need to cover if with either your hand or plastic to seal it, if you can see what side it's on lay the casualty down on that side, that stops the blood running into the undamaged lung, also check for more stab wounds, often there's lots..
If it's a gunshot check the other side of the person as well, almost all rifle and many pistol rounds will go right through a person, small entry wound, big exit wound is usual but not always the case.

Bleeding apply pressure and a dressing if you have one, if it's an artery ( spurting blood) you'll probably need the pressure point  or a tourniquet to control it, you can improvise these if you haven't got a proper one, ideally something wide is better, a belt maybe, about 4 inches the heart side of the wound or amputated limb.