unexpected expenses

my mom had been having dizzy spells,head aches,to her blood pressure being to high,or to low.and chest pain since the last part of last year.but on a small scale,at that time..they started getting worse with each passing week/month..one doctor was saying,its her lungs.another was saying its her heart..it was kind of,like they was playing hot potato with her and her health,by tossing her back n forth.for i guess 3 to 4 months...one of her doctors finally set it up, where she has a oxygen concentration machine at home..one doctor set it up for her to have a cath,or what ever done,the other day.to see if it was/is anything to do with her heart. thats when we all learned that it's 2 artery's. one was at 75% blockage,and the other was at 95% blockage..that took place day before yesterday.so they decided to do open heart surgery.in which that'd take place in Houston tx..and keep her in the hospital just to keep a eye on her n all,untill she got transported to houston. that night,she went down hill.it looks like she was having,or did have a heart attack..i get a phone call from them around 4:50 yesterday morning,telling me to whats going on with her.so i got dressed and went to the hospital.just to find out things might be worse then they were letting on..and yes it was. it's between 6am and 7am by this time.they did what they could.but yet she still wasn't responsive from recovering from they used to put her under..they finally got her transported to houston and did the double open heart surgery..she made it through the surgery all right. and was still recovering,by i guess 8pm yesterday.so i came home. she's regained conciseness. and she's responding to what people are saying,in the different ways she can right now..she has tube(s) going down her throat and into her lungs,for drainage or what ever..and a oxygen mask over her mouth,to help out..she's still having some issues with her blood pressure. but not to bad. they'll send her up to a room once thats been dealt with..so i now have 2 worries.1st,is my mom recovering from that,in which it looks like she will.the other,is.will that send our medical expense's sky rocketing,big time? ...we already owe i dont know how much in medical bills,from previous medical expense's.but yet.this will send the bills on up.