Medicine is in many ways a black art. It is not a science; it is an art guided by science. The guidance the science offers varies considerably from, for example, bone surgery to psychiatry, but the uncertainty is always there, even in the high-tech surroundings of the PICU. Our complicated machinery can mask the fact we occasionally are unsure about what we are doing and why. Sometimes we have almost no idea what is going on with our patients, a circumstance some doctors have trouble admitting both to themselves and to patients’ families. It is a difficult thing, at least the first few times you do it, to talk to a family when much of what you say describes your ignorance. With practice, though, it gets easier, especially when you know — really, truly know — that you can always do something to make a sick child more comfortable.
If you want to read more about an in-the-trenches account of how physicians deal with uncertainties, I suggest Atul Gawande’s book Complications (Picador, 2002).