When is testing too much?

I remember a story I heard once about a child that was in a hospital in intensive care and was connected to all the monitoring machines, including one that watched the heartbeat electrical signals. The child’s condition took a sudden turn for the worse and showed all the signs of a lack of blood flow to the brain. The doctors couldn’t figure out why because the heart was beating, and they were about to send the child for a scan to look for a blood clot that would cause a stroke when one doctor thought to listen for a heartbeat. There was none. The machine showed that the heart was beating but there was no sound to confirm the beat. The doctors were able to determine that swelling around the heart was putting pressure on the heart and preventing it from beating. I don’t know how, but they reduced the swelling and the child’s heart started pumping again.

Why does this story come to mind? Because the machine that monitored heart...