Ask the Clinical Instructor: A Q&A column for those new to the cath lab
GFR is glomerular filtration rate. This should be very important to you and the staff taking care of the patient. GFR is better than creatinine and BUN for measuring kidney disease. Creatinines can be at high levels, but it can still be within normal limits for that patient because creatinines also measure muscle metabolism. Your more muscular patients, therefore, will have a higher level, which is normal for them.
GFR was originally measured by injecting inulin. Inulin is not reabsorbed by the kidneys, so it is excreated and can be measured accurately. GFR is measured in milliliters/minute (ml/min). Doctors can estimate GFR by using creatinine clearance, age, race, gender and other factors. There are 5 stages of kidney disease that we use. A GFR greater than 90 is normal; this is stage 1. Stage 2 is a mild decrease in GFR, (GFR is 60-89). Stage 3 is a moderate decrease (GFR is 30-59). A severe decrease in GFR with kidney damage (15-29) is stage 4. Less than 15 means the patient requires a kidney transplant or dialysis. Kidney failure can cause metabolic acidosis and make your patient very ill. Contrast selection becomes very important with impaired kidney function, as contrast is toxic to kidneys and can kill off the glomeruli responsible for filtering out waste products.
Still learning about the wide variety of patients that visit the cath lab? Could your question be one that others share as well? CLD can help.
Submit your question to:
Jason Wilson, RCIS at hrtfixr7 (at) yahoo. com