My friend is under a lot of pressure & is also having a lot of panic attacks. I have found that getting any onlookers to go away & then sitting quietly infront of her holding her hands & reassuring her really helps. Also if a paper bag isn't available, try telling her to blow out like she's slowly blowing a candle out...and just concentrate on blowing the air out...this will decrease the amount of oxygen she's taking in & so ease the symptoms of panic, such as dizzyiness, numb lips and hands etc. She will automatically breathe in, but it seems to stop the gasping.
Very important to get to the root of the anxiety when the crisis has passed...tackle that & maybe she could be free of the panic. Good luck x