When thinking about someone having diarrhea and/or vomiting, you have to think about what it does to the body. Look at all of the assessment skills- mental status, vital signs, skin, urine output. If you have a change in mental status such as confusion, or vital signs such as body temperature, are they sweating, is the skin dry, moist, turgor is also important, heart rate, is it fast, slow or normal, blood pressure is it high, low or normal, respirations are they fast, slow or normal. With a fluid loss you can see a faster heartrate, lower blood pressure, and the temp could be elevated, normal or low depending on what stage of dehydration they are in. Sweating also can cause a loss of body fluid, especially if fever is present, the body uses a significant amount of water in the form of sweating to cool the body down. Heat and exercise can also play a large part in becoming dehydrated, through sweating, so it is not always visible. Urine output is another thing that you would look at- the amount, color, frequency. Urine will tend to be dark in color, with low amounts of output and a decrease frequency. You would also need to think about what could be other diagnosis such as diabetes, electrolyte imbalances, UTI's, etc on what is causing the diarrhea and vomiting. Other thing to look at is medications, what are they taking-prescribed and non prescribed. Tylenol is a big one of nonprescribed medicines that interact with coumadin if they are on blood thinners.
So when you think about the hemoconcentration, what happens? It is defined as a increased concentration of cells and solids in the blood from loss of fluid in the tissues. Which equals dehydration. So would the INR be increased or decreased? You are correct, it would increase. Hope this helps you understand more about having diarrhea/and or vomiting and the INR values.