Did Pitohui have a special nerve gear? In the last few episodes of Gun Gale Online, it was shown that Pito was hyperventilating and should have been ejected from the game, but she wasn't. 

It was discussed that she could be using a NerveGear, but this was never elaborated on.

Does the manga or other sources mention if Pito actually did have a NerveGear? Or just a modified version of the new one?
She was using the original Sword Art Online Nerve Gear, which had the capability to kill you.

The difference with the Nerve Gear and the Amusphere are the safety mechanisms put on the Amusphere to prevent the software from killing you by inducing high voltages into your brain. This is also why Pito didn't get auto ejected when hyperventilating.

Yes, Pito using the Nerve Gear could still kill her, but GGO doesn't have the functionality to fry your brain when you die... (duh) like SAO did