Low Power Laser Protects Human Erythrocytes In an In Vitro Model of Artificial Heart-Lung Machines

: The protective effect of the low power helium‐neon (He‐Ne) laser against the damage of human erythrocytes in whole blood was examined in a perfusion model using an artificial heart‐lung machine. Preserved human whole blood was diluted and perfused in 2 closed circuits with a double roller pump. The laser irradiated one of the circuits (laser group), and none the other (control group). In the laser group, erythrocyte deformability and erythrocyte adenosine triphosphate (ATP) levels were significantly higher, and free hemoglobin levels were significantly lower than those in the control group. Subsequent morphological findings by means of scanning electron microscope were consistent with these results. Low power He‐Ne laser protected human erythrocytes in the preserved diluted whole blood from the damage caused by experimental artificial heart‐lung machines. The clinical application of low power laser treatment for extracorporeal circulation is suggested.