Ask the Clinical Instructor: A Q&A column for those new to the cath lab

A young female patient came to our cath lab with very high PA pressures. The doctor said that she needed to have nitric oxide treatments. What are nitric oxide treatments? Pulmonary hypertension occurs in people with chronic obstructive pulmonary disease (COPD), those with recurrent pulmonary embolism, and those with damaged endothelium. Endothelium releases nitric oxide and acts as a vasorelaxer. I don’t know what this patient’s reason for the pulmonary hypertension was or how she was feeling. It sounds like the physician thought she could benefit from nitric oxide as an inhaled treatment to relax her pulmonary artery (PA) and allow the blood to flow through a little easier, thereby dropping her PA pressure. Recently, I was reading a study an industry representative brought in (trying to read it, anyway). I was able to understand some of it, but there was much that I did not understand. Could you help break down some of the terminology? Some clinical studies are very difficult to read. Sometimes there are different variables in the study that can change how you look at the study. There are blind studies, double-blind, randomized trials, letters that stand for groups of people, letters that stand for the likelihood of something being true…you are right, there is a lot that can lead to confusion. Taking a course in statistics would be ideal preparation, but in the meantime, here are some pointers that may help. n is the number of subjects in the study. Larger studies usually have more reliable data than smaller ones, so take this number into consideration. p-value: the p-value represents the likelihood of something being true. For example, if a study shows a p-value of .045, it means that 96 times, what was studied is likely to happen, and 4 times, it could happen by chance. Obviously, the smaller the p-value, the more reliable the study. Cohort study: a cohort study involves a group of people who have the same disease or condition, or who are receiving the same treatment, and are studied together over a period of time. The results are compared to a group of people who comprise the control group, and who did not receive the treatment. Of course, there is much more to learn about scientific studies than I can cover in this column. I would encourage you to continue to study on your own in order to better understand what you are reading. The website clinicaltrials.gov may be a good place to start, as it offers a basic glossary of terms.

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