Applicability of a Portable Non-Invasive Device Evaluating Hemoglobin and Peripheral Circulative Function in Eumenorrheic Young Women with Premenstrual Discomfort.

A non-invasive measurement using near-infrared radiation has been widely used and provides valuable information in the clinical and basic medical research field. Our research group has recently invented a portable non-invasive monitoring device (Astrim) to determine hemoglobin levels by using the principle of near-infrared spectroscopy combined with analyzing optical images of venous blood vessels taken by a charge-coupled device camera. The devise has also been designed to calculate the venous oxygenation index (VOI) based on the ratio of the light absorption of oxyhemoglobin (HbO₂) and deoxyhemoglobin (Hb). Previous studies have shown that the VOI is a reliable indicator in evaluating peripheral venous oxygen metabolism and skin blood flow under different physiological circumstances. To elucidate the potential clinical use of the index in the gynecological field, we measured the VOI during the menstrual cycle and investigated whether the VOI indicating peripheral circulative function is influenced by the fluctuations of ovarian hormones and/or various physical and emotional symptoms a majority of women of reproductive age experience in the premenstrual phase. Twenty five eumenorrheic healthy young (20.4±0.2 yrs) women not taking any medications participated in the study after giving their informed consent. All subjects were studied during the follicular and the late luteal phase for three consecutive menstrual cycles. All experiments were performed in the morning after the subjects fasted overnight. The subjects rested for 10 minutes at room temperature sitting in a comfortable chair. The left middle finger was then placed on the detection probe of the Astrim, and hemoglobin levels, venous blood vessel width, and the VOI were automatically determined. The VOI was calculated as the following equation: VOI = −h2/h1. h1 and h2 was defined as the degree of light absorption of HbO₂ and Hb at the wavelengths of 805 and 660 nm, respectively, in the near-infrared region. It should be noted that HbO₂ and Hb absorb light equally at 805 nm, whereas at 660 nm absorption is primarily from HbO₂. The skin temperature of the finger was also measured by digital thermometer. All data was taken ten times. The emotional and physical symptoms of each subject accompanying the menstrual cycle were assessed by the daily rating score throughout the entire study period. The oral temperature and urinary ovarian hormones adjusted for creatinine significantly increased in the late luteal phase. The statistical analysis verified the reliability and repeatability of the VOI. While most subjects experienced mild physical and emotional discomforts in the late luteal phase, none suffered to the point of disturbing their daily activity. Concerning the VOI, we found that it decreased more significantly in the late luteal phase than in the follicular phase (−76.0±3.3 vs. −68.2±2.2; P < 0.05). Our data demonstrated that the VOI reflecting peripheral oxygen metabolism is a valuable and practical index to non-invasively evaluate peripheral circulative function under various physiological conditions. Psychological and vasomotor complaints, and peripheral circulation disorder would be more apparent in the climacteric stage. Thus, the present study further supports the clinical use of the VOI in the gynecological field, in addition to the potential applicability to basic medical research and public health promotion projects.