Hi love, I’m a theatre nurse and I often assist in patients getting out under anaesthetic. Asthma is so so common but I have never seen anyone’s asthma flare up due to anaesthetic. They like you to bring your inhaler with you and take a few puffs beforehand but Iv never seen or heard of any issues.
If you’re still concerned just think if it this way, if the tube DID trigger an asthma attack the tube would already be in place and holding open your airways so you could still breathe xx