EVALUATION OF THE IITC TAIL CUFF BLOOD-PRESSURE RECORDER IN THE RAT AGAINST INTRAARTERIAL PRESSURE ACCORDING TO CRITERIA FOR HUMAN DEVICES

National standards govern the manufacture and marketing of medical dev ices in the United States, including those for indirect blood pressure measurement in man, There are no comparable standards for devices for recording in laboratory animals. Noninvasive tail cuff blood pressure (BP) recording in the rat is widely accepted, but beset by methodolog ic difficulties. Intraarterial recording is regarded as the ''gold sta ndard'' but is invasive and also susceptible to methodologic error. We compared the IITC Mark 12 photoelectric/oscillometric tail cuff syste m (IITC Life Sciences, Woodland Hills, CA) versus simultaneous femoral intraarterial recordings in spontaneously hypertensive rats, during a nesthesia and 1 to 2 days after recovery (150 recordings under each co ndition), according to the guidelines for human data collection and an alysis suggested by the American National Standard for automated sphyg momanometers. Within- and between-observer disagreements in estimates made by two observers from 40 anesthetized recordings were less for in traarterial measurements than for the tail cuff method. Within-observe r differences (mean +/- SD of differences [SDD]) for systolic, diastol ic, and mean pressure were 0 +/- 1, 0 +/- 1, and 0 +/- 1 mm Hg for int raarterial versus -1 +/- 3, 0 +/- 8, and 0 +/- 5 mm Hg for tail cuff. Between-observer differences were 0 +/- 2, 0 +/- 1, and 6 +/- 2 mm Hg versus 5 +/- 4, 13 +/- 7, and 0 +/- 5 mm Hg, respectively. Differences between tail cuff and intraarterial methods were 16 +/- 13, -5 +/- 11 , and 2 +/- 8 mm Hg in anesthetized animals and 8 +/- 14, -5 +/- 9, an d 0 +/- 9 mm Hg in conscious animals (39% to 82% of differences exceed ed 5 mm Hg). The upper limits of clinically acceptable disagreement in the American National Standard are: mean of 5 mm Hg, SDD of 8 mm Hg. The disagreement between tail cuff and intraarterial recordings cannot be ascribed to either method with certainty. These findings do not su pport the manufacturer's guarantee of tail-cuff readings within ''5 mm Hg of intraarterial.'' Inaccuracy and unreliability of devices intend ed for laboratory animal use have considerable scientific, fiscal, and ethical implications. Marketing of these devices should also be gover ned by rigorous standards. (C) 1997 American Journal of Hypertension, Ltd.