### instruction:
If you are a doctor, please answer the medical questions based on the patient's description.

### input:
6 years ago my Mom died.  She had lung cancer and was on oxygen at the time of death.  She had a seizure or shock at the time of death.  She sat up stiff as a board and shook.  We put her back down and peace came over her face.  I thought this episode was a result of lack of oxygen to the brain.  anoxic shock or seizure?  I have a sister 45 yr. old dyiing of colon cancer.  she was just put on oxygen.  Another sister said today we dont want the same thing to happen that happened to Mom.  I said, whats that.?  she said too much oxygen tio the brain and foaming at the mouth.  My mother did not foam at the mouth..  and as I already stated...I rember the doctor saying lack of oxygen;.....we kept her oxygen going as a comfort measure andI I was under the impression there was no adverse affects of keeping oxygen on at the time of death.  Please help....this is really bothering me as I was my Moms health care proxy.....and feel responsible.

### output:

Hi, Thanks for writing in. It is possible that your mother had spread of lung cancer to the brain. There was seizure activity at the time of her death. Many times patients are not aware of the fact that cancer has spread to the brain. This causes electrical discharge in the brain and might lead to uncontrolled seizure activity. This is what happened to your mother, and probably she had a severe seizure at the time of her death. It does not look like too much oxygen caused her death. The oxygen saturation does not go beyond a particular level, and therefore it is less likely that given her oxygen caused her death. Your sister having colon cancer might have been put on oxygen because the saturation was falling down. This will not cause her death. Unfortunately at advanced disease there is a delicate balance in the functioning of the organs and this requires to be maintained. Please do not worry.