This case advises that a history of traumatic events, particularly suffocative events like near-drowning, could lead to panic and posttraumatic flashbacks in a subject without any former or current posttraumatic stress disorder symptoms or anxiety symptoms. This case emphasizes that the biological underpinnings of flashbacks might be similar to panic attacks and that CO 2 -induced panic could reactivate traumatic events.
It was a lot of CO2, like 30%, as compared with the 5% or so that we usually breathe. But the flashback was very quick.