Development of a real-time blood damage monitoring device for cardiopulmonary bypass system using near-infrared spectroscopy.

Abstract

The optical properties of hemoglobin could indicate the degree of hemolysis. We aimed to utilize this to develop a real-time blood damage monitoring device for cardiopulmonary bypass (CPB) systems. The real-time blood damage monitoring device comprised a near-infrared spectroscopy optical module with a fiber spectrometer and monitoring platform and computer software developed using LabVIEW 2017. The fiber spectrometer operated at wavelengths of 545, 660, and 940nm and contained a detector fiber bundle (source-detector distance = 1.0-2.5cm). CPB operation was simulated using an artificial heart-lung machine with a flow rate of 3, 4, or 5L/min. Four hundred milliliter of anticoagulated porcine blood was continuously rotated for 4h. The transmittance, reflectivity, and absorbance of the blood were measured using the optical device at a frequency of 25Hz and then digitally averaged into 1-s interval. Samples of damaged blood were collected at regular intervals for in vitro hemolysis tests to calculate the normalized index of hemolysis (NIH). All experiments were repeated three times. We prepared 28 blood bags containing 400ml of anticoagulant. Paired t test was used to examine the test-retest reliability of the differences between the three methods and control samples. Statistical tests revealed significant differences in the mean values between the test and control groups over time (P< 0.01). Relationship was established between the real-time monitoring results and the NIH values. An effective blood damage detection method that combined in vitro hemolysis tests and near-infrared spectroscopy was achieved. The results demonstrate the clinical potential of a real-time, low-cost, and reliable blood damage monitoring device to improve the safety of CPB operation.