METHOD SPECIFICITY OF NONINVASIVE BLOOD-PRESSURE MEASUREMENT - OSCILLOMETRY AND FINGER PULSE PRESSURE VS ACOUSTIC METHODS

1 The agreement of blood pressure measurements by stethoscope ausculta tion (SBPa, DBPa-IV and DBPa-V), oscillometry (Dinamap(R); SBPo, and D BPo) and digital photoplethysmography (Finapres(R); SBPf, and DBPf) wi th the graphical analysis of the analogue microphone signals of vascul ar wall motion sound (SBPg and DBPg) was evaluated in eight healthy su bjects in the presence of responses to the intravenous infusion of 1 m u g min(-1) isoprenaline. 2 In general, there was good agreement betwe en the SBP/DBP-measurements based on auscultatory Korotkoff-I- and -IV -criteria and the reference method; the average method difference in e stimating the isoprenaline responses for SBPa-SBPg was: -1.1, 95% CI: -5.4 to 3.1 mm Hg with a within-subject between-method repeatability c oefficient (REP) of 11.6 mm Hg and for DBPa-IV-DBPg : 3.5, 95% CI: -0. 5 to 6.5 mm Hg, REP: 11.5 mm Hg. The ausculatation of Korotkoff-V subs tantially overestimated the isoprenaline induced reduction of DBP: met hod difference DBPa-V-DBPg : -11.3, 95% CI: -17.8 to -4.7 mm Hg, REP: 31.8 mm Hg. 3 Oscillometry yielded good approximations for the SBP res ponse to isoprenaline (average method difference SBPo-SBPg : -2.9, 95% CI: -9.0 to 3.3 mm Hg, REP: g 17.6 mm Hg) but was poorly sensitive wi th regard to the DBP responses: method difference DBPo-DBPg: 6.5, 95% CI: -1.3 to 14.3 mm Hg, REP: 25.7 mm Hg. 4 Whilst the finger pulse pre ssure agreed well with regard to DBP (method difference for the DBP re sponses to isoprenaline: DBPf-DBPg: 1.8, 95% CI: -5.1 to 8.6 mm Hg, RE P: 18.5 mm Hg) it was rather unsatisfactory with regard to SEP (method difference SEP(f)-SEP(g) : -14.1, 95% CI: -28.2 to -0.1 mm Hg, REP: 4 9.9 mm Hg). 5 Non-invasive measurements of blood pressure are method s pecific estimates likely to be subject to method x effect-interaction. In consequence they are not interchangeable.