This is too big of a mistake to excuse. There should be something which tests the gas lines before they're given to patients. It is very frightening that a faulty gas line could switch which gas is distributed - this should be addressed, and the hospital staff should be trained to spot the difference immediately.
As a patient, I would like to know that the people handling my care are 100% focused on the task at hand. If I have any doubts that the person administering a drug or gas to me is not focused on my care and well being, they are not fit to take care of another human life.
There are clearly a large number of factors that caused this, and at any point this tragedy could have been prevented. The hospital staff needs to take a long look at thier actions and some serious changes need to be made at this hospital. It was not simply an accident.
The hospital staff that gave a baby laughing gas instead of oxygen should not have been so careless. Unfortunately, this mistake turned deadly for the baby. The hospital staff should have been more thorough, closely paying attention to what they were giving the baby. This is why hospitals must be held liable when medical errors occur; so that medical staffs will be more careful in the future.