I looked into her anxious eyes and could feel her need to talk. The child sitting placidly on her knee was beautiful. The love between them was obvious and it was clear this was a special and precious child. “It's just that with the Blalock shunt in, I feel I have to be more careful with him, even if he just seems to have a cold.” I didn't know what a Blalock shunt was, but I knew this woman half expected me not to know and would patiently explain it to me. She did. “You see, Doc, he was born with Fallot's tetralogy and one way of overcoming that is to join up the artery that goes to the arm to the one that goes to the lungs. That way the lungs will get a decent blood supply and that does for a while.” We talked more about the difficult and traumatic times there must have been when her young son was having cardiac surgery, and how well he seems to have done since then.

I was doing a general practice locum then. It was a dark December evening and even though it was …