Evaluation of a new ambulatory blood pressure device

We assessed the OSCILL-IT ambulatory blood pressure (BP) recorder (FIGI srl, Rome, Italy) according to the performance criteria set out by the British Hypertension Society (BHS) protocol. The OSCILL-IT is a portable, noninvasive recorder that uses a process that correlates systolic, mean, and diastolic areas, identified on the oscillations, to the cuff absolute pressure. According to the recommendations of BHS, a large heterogeneous population (100 subjects: 52 men aged from 19 to 79—median 44 and 48 women from 19 to 74—median 54) was recruited in order to assess accuracy and to analyze, in addition, the effects of observer agreement and BP level on the observer–device differences. With reference to BP level, we suggest also a new graphic approach. Four sets of sequential, same arm, comparative BP measurements were obtained, performed by the OSCILL-IT recorder and two skilled clinicians using a mercury column, for each subject. We used a linear combination for the statistical evaluations. We confirmed the observer agreement through the frequency distribution of BP as a function of the observer and through the differences between observers. We compared OSCILL-IT with sphygmomanometric readings: the differences were not significant. A visual inspection, with the addition of regression lines, showed that there were no variations in differences at the changing of BP level. The difference between observers and OSCILL-IT was 0.2 ± 5.3 mm Hg and 0.2 ± 5.8 mm Hg both for systolic BP (SBP) and diastolic BP (DBP). The level of agreement, according to BHS criteria, showed that 64% of all systolic and 70% of all diastolic readings obtained by the OSCILL-IT were within 5 mm Hg of the sphygmomanometric determinations. Therefore, the grade is C for SBP, even if 93% of SBP and 95% of DBP obtained by the OSCILL-IT were within 10 mm Hg of the sphygmomanometric determinations. These analyses demonstrate that the OSCILL-IT satisfies the accuracy parameters and the additional linear regression yields graphics more immediate.