Non-invasive measurement of hemoglobin concentration using magnetic plethysmo gram

A method for determining the concentration of hemoglobin in arterial blood, non invasively, is explored in this paper. A permanent magnet is placed just above the radial artery of a person whose hemoglobin concentration is to be ascertained. The flux produced by the permanent magnet (that links with the blood flow in the radial artery) is sensed to obtain a signal called magnetic plethysmogram (MPG). In this paper, an analytical model for a magnetic plethysmogram is derived. Using the proposed analytical model, a method of estimation of the concentration of hemoglobin in arterial blood is derived. The proposed method is then validated through a limited clinical study. The results of the clinical study establish the viability of measuring hemoglobin concentration, noninvasively, using magnetic plethysmogram.