Dear Dr. Roach: I recently had surgery, and my blood pressure was monitored with a catheter. The readings were higher by 30 to 40 points compared with cuff measurements taken at the same time. They were having a hard time getting the catheter readings down to 170. I am wondering which readings are to be used under blood pressure guidelines. R.R.
Answer: A catheter (thats just a name for a tube inserted in the body) measures blood pressure directly. When people are in the operating room or in the intensive care unit, a catheter often is placed in the artery to give instant, direct measurements of the blood pressure. Several studies have shown that these are more accurate than noninvasive blood pressure measurements, especially in people with very low blood pressure.