Differences of blood pressure values between Korotkoff and oscillometric device

SubjectUsing intro-aortic BP as reference,to compare the accuracy of a Korotkoff sound electronic device (Hanvon FY730) and an oscillometric device (Omron HBP-1320T3) in BP measurement, MethodsBP was measured in catheterization coronary angiography. A crossover design was adopted for the using sequence of the two kinds of devices. The average of two BP readings were recorded as the final SBP, DBP and mean arterial pressure (MAP). Non-invasive BP measurement was initiated when the intro-aortic BP curve was stabilized, and the intro-aortic BP curve was simultaneously recorded for 15-20 seconds. BP differences ({Delta}BP) between non-invasive and its relative intro-aortic BP values were calculated as Oscillometric BP - intro-aortic BP difference (Osc-Ao) or Korotkoff sound method - intro-aortic BP difference (Kor-Ao). ResultsUsing intro-aortic BP as the reference, the Korotkoff sound device provided closer readings compared to the oscillometric device.The Kor-Ao SBP was 19.5 {+/-} 17.6 mmHg, but Osc-Ao SBP was 24.8 {+/-} 20.2 mmHg (P < 0.001). Similarly, the MAP difference was smaller for the Korotkoff device (10.5 {+/-} 10.9 mmHg vs. 13.7 {+/-} 11.3 mmHg, P = 0.007). Although the DBP difference was also smaller for the Korotkoff device (6.1 {+/-} 12.3 mmHg vs. 8.1 {+/-} 11.5 mmHg), but no statistical significance (P = 0.147). ConclusionUsing intro-aortic BP reading as reference, the Korotkoff sound device provides more accurate brachial SBP, DBP and MAP values against the oscillometric device.