The following is a link to a PDF file titled, Living Within The Window of Tolerance: The Different Zones of Arousal, that A. gave me last week. This may be helpful to many of you who struggle with triggers and panic attacks.
The first page illustrates the three arousal zones: Hyperarousal, Optimal Arousal, and Hypoarousal. With PTSD, we tend to live outside of the Optimal Arousal Zone (the middle zone), often fluctuating between the Hyperarousal and Hypoarousal Zones. The key is to train ourselves to be able to spend more time in the Optimal Zone.
The other pages are exercises to practice that will help with managing these episodes. There are several different exercises related to specific feelings and reactions to help you identify what you are experiencing and ways to manage them based on these reactions.