I will be having: Facelift, Neck, Lower Blepharoplasty, Face fat grafting , Brow lift (endoscopic –because apparently no doctors do coronial anymore??) in July and I've been told the surgery will take 6-7 hours. So I will be under general anaesthesia for that long. Is this safe? I'm scared, what if I don't wake up? I have a history of varicose veins & hereditary clotting. What if I get a heart attack in the middle of being under?