Blood pressure measurement by pulse oxymetric method and comparison with conventional technique.

Background: Measurement of systolic arterial blood pressure using a pulse oxymeter involves the evaluation of plethysmographic waveform during inflation and/or deflation of a blood pressure cuff. The purpose of this study was to determine that during slow inflation and deflation of cuff, which one of the pulse oxymetry-based readings of blood pressure is in best agreement with the value obtained by conventional method.

Methods: Blood pressure was measured in a sample of 50 healthy adult volunteers with conventional and pulse oxymetric methods. The degree of agreement between two methods was calculated.

Results: The mean difference between systolic blood pressure and pulse oximetric blood pressure during inflation of the cuff was 0.06 +/- 1.75 mmHg which was not different from zero. The highest correlation was also between these two pressures (0.988).

Conclusions: This study shows that the best agreement is between systolic blood pressure and pulse oxymetric blood pressure during inflation. We conclude that for accurate measurement of blood pressure by pulse oxymetric method it is necessary to inflate the blood pressure cuff at a slow speed for the pulse oxymeter to have enough time to reach equilibrium state.