I have seen in almost all video-games and movies that when someone is stabbed by a sharp knife, the victim "takes out" the knife from his body. Does it help the victim in anyway? What should be the possible "first-aid" steps that can be taken to prevent death of the person? Can the knife stay in there till the medical help arrives? Or is there nothing constructive that can be done ?
If the weapon is still in the wound : don't touch anything and call the appropriate emergency system (varies from country to country).
Never attempt to remove any penetrating object still in situ as this may cause more serious bleeding
If the wound is open, apply little pressure on it with clean clothes. And call the appropriate emergency system, keep applying pressure until ambulance/doctor arrives.
Yes, you can save a life by decreasing the out bleeding, or at least make recovery from the wound possible.
Source : Red Cross and this paper from Melby V. and Deeny. P
The only time to remove an impaled object is if it is occluding the airway. All other times it should be left in place.
If it is in place provide a dressing which supports it and prevents it from moving. Cravats and some roller gauze work well for this. Control any other external bleeding and other problems. Check for other injuries, such as multiple stab wounds.
For stab wounds where the object is not in place control bleeding aggressively. For stab wounds to the neck or chest place an occlusive dressing on entry and exit wounds.