Interoception
What If the Patient Feels the Change Before the Monitor Can Measure It? I have watched something happen with my son Alex for more than twenty years. He knows. Sometimes Alex knows something is changing inside his body before a monitor shows us anything unusual. It has happened too many times, over too many years, for me to dismiss it. And lately I’ve been wondering: How close to the actual mechanism is Alex able to feel the change? I don’t mean that he consciously thinks, My CO₂ is changing, my blood pressure is about to fall, or this particular physiologic pathway has just been disrupted. I mean something more fundamental. Maybe he is sensing the earliest downstream effects of a physiologic change , while our equipment is waiting for that change to become large enough to appear in the variable it measures. Because a monitor and a human nervous system aren’t necessarily measuring the same thing. A pulse oximeter measures oxygen saturation. A blood-pressure cuff mea...
