You know, that is a damn good theory! It happened when he approached them too no?
The only thing I can think of to try and disprove this... Is that I don't really recall any of them catching their throats in the past much like Ichigo is doing now or screaming like that... But hey.. Kubo is far flung from being a consistent author!
Altho I really do like this theory... I still think it's more likely to be his hollow or the hyogyoku... Not to say you're wrong or anything... cos it is bloody damn possible!