I ask this question to the old wise "GOOGLE" many times and never found anything more than a vague answer . . . SO here goes (tears)!

 I have only spoken to two other mothers who lost a child with SMA and in all three cases, Katie included, it was loss of oxygen.

All three of us had to make the decision when to take the oxygen away. One child went to all of the specialists on the east coast and used little medical intervention, the child was on oxygen for awhile and had home care nurses every day, her parents had to make the decision to take her oxygen and she died in their bed that night.

The other was a young mother who followed all of the protocols except tracheal tube, and she died in the hospital with in one day of removing oxygen.

We were "lucky" (if that is appropriate when speaking about the death of your child) Katie was born in our home and died in our home.  The only time any needle went into her body was when they took the blood test to determine SMA and when she got her immunizations at 1 month (or six weeks).  Around 5 months of age her health deteriorated within weeks. . I think one of her lungs had collapsed, but I never confirmed it. Hospice came weekly and I told them in my initial meeting, I did not want to know when she was getting sicker. . That was the only way I could care for her and my other child knowing she was going to die.

One Sunday night (April 26, 2009) she had a hard time sleeping.  We put the O2 sensor on her foot and by morning her levels had dropped below 80% many times.  In the morning I hooked her up to the portable oxygen for a while to help her get some rest, but she never came off of it.

By 3pm, I was shuffling to get more oxygen in the house when our second to last bottle ran out and she was on it. . . She plummeted. . We quickly got her reconnected and back up to 70% oxygen but I knew. . I looked at the hospice nurse and said "OMG that’s it isn’t it?" she said nothing, just smiled (I LOVE YOU HOSPICE WORKERS) then I had to convince my husband to let her go. . (There was a lot that transpired in this time but I can’t write it because I can’t see the computer with tears in my eyes) . . . Ultimately, about an hour or two later, we took Katie to the sofa, held her in our arms and took the oxygen out of her nose. . And cried. She looked as us with glazed eyes (morphine) and I don’t know if she made any sounds at all because of our crying but she was gone in minutes. And that is how SMA killed her.