Hi @freedancer69,
@walkinggirl is right on with her assessment. Open heart surgeries have a number of routine protocols that include a variety of lines, tubes, devices that are all part of your pre and post-op experience. The endotracheal tube is a vital piece of this picture and how long this tube remains depends on your recovery after the surgery itself is over.
Just like @walkinggirl, I was extubated (had the breathing tube removed) right around 4 hours after surgery. I was awake and remember this well. They are trying to get your body temperature up, get you breathing on your own, get you waking up, and some of the lines can start to come out.
There is no pain with the tube coming out, it's important to listen to their instructions, however.
Knowing that you have a tendency to panic is something to discuss with your surgical team ahead of time. Let them know you are prone to panic attacks. They will do all they can to alleviate pain, discomfort and anxiety.
I am not familiar with septal myectomies at the University of Colorado, but I am pretty sure most all open heart surgeries have many similar protocols.
Were you referred to U of C as your first choice? Have you had a chance to learn how many septal myectomies their surgeons perform each year?