If the access or needle gauge is incorrectly identified in your records, it directly affects the accuracy of the AAPR and VAPR results. For example, if your patient had a graft that you were using 16 gauge needles in during treatment, but your records showed that you were using 15 gauge needles, VAPR and AAPR results would appear elevated. This is because blood flow rates would be reduced and arterial and venous pressures would be elevated, causing the calculated results to be erroneously elevated, because they were made using the coefficients for 15 gauge needles.