"babies given mediation based on an average weight"

My 8 month old daughter went for a EEG. She was required to have sedation to help her sleep. When we arrived I asked if my daughter would be weighed. The response was no the prescription for the sedation was made for an average weight child of this age. This weight was 6kg my daughter weighed over 9kg. This was in her medical notes as she was weighed in the hospital in January. This resulted in my daughter not having enough sedation and she was very tired and distressed but didn't go to sleep. She screamed for 2 hours and was very upset. The nurse who was there to be with my daughter did nothing as they were on their phone pretending to read my daughters notes. I asked if my daughter could have more of the sedation as befits her weight and I was told no as too much is dangerous. My fear is if my daughter had not weighed the average 6kg and had been given the drug she could have had serious repercussions. Why was my daughter given any medication without being weighed? Why had the doctor prescribing the medication not looked at her notes to see her weight? I was also not given a consent form to sign which the appointment letter informed me I would. This all resulted in the EEG not being completed. I then received an answer phone message from a doctor asking if "i felt she still needed the EEG and to call the secretary" this is something I feel should have been discussed face to face with a trained professional not a secretary.