Clinical evaluation of the Accutracker II ambulatory blood pressure monitor: assessment of performance in two countries and comparison with sphygmomanometry and intra-arterial blood pressure at rest and during exercise.

In order to assess the Accutracker II (Suntech Medical Instruments, Raleigh, North Carolina, USA), a relatively new ambulatory blood pressure (BP) monitor, versus standard forms of BP measurement, we compared same- and contralateral-arm measurements made, via a t-tube connected to a mercury column sphygmomanometer, by two clinicians using a teaching stethoscope and by intra-arterial recordings. Average systolic BP values obtained using the Accutracker II were similar to both the mercury column and intra-arterial determinations, but average diastolic BP values were lower than both the average mercury column (2.8 +/- 4.2 mmHg, P less than 0.001) and intra-arterial measurements (2.0 +/- 4.7 mmHg, P less than 0.02). During isometric exercise and 100-watt bicycle exercise, there were greater limits of agreement for the differences in BP between the Accutracker II and the intra-arterial transducer than were observed for the resting measurements, but these differences were no greater than those observed between intra-arterial and clinician-determined BP measurements. The clinical performance of the Accutracker II was assessed using 119 hypertensive subjects (84 in Norway and 35 in the USA) who wore the monitor for 24 h. While there was good-to-excellent data return in both countries, there were significantly less error codes secondary to excessive arm motion observed in Norway. Our data demonstrate that the Accutracker II is quite accurate compared with both the mercury column and intra-arterial methods of measuring BP, and performs well during 24 h outpatient activities. Our findings also indicate certain geographical differences which may be important in the performance of ambulatory BP-monitoring studies.