Changes of Pulmonary Function Following Transfusion of Stored Blood

Abstract

Ventilatory volumes, blood gases and other aspects of pulmonary function were measured before and after intra‐operative transfusion in 16 patients who had undergone operation under general anesthesia. One group consisted of eight patients transfused with 1275 ml of stored blood passed through a standard nylon mesh filter (SF group) and the other consisted of eight patients transfused with stored blood passed through a dacron wool filter (DWF group). Since respiration of the patients was depressed slightly due to preanesthetic sedation, lowered V e , V t , and elevated Pa co 2 , respiratory dead space ratio V d /V t were observed either in the SF or DWF group before anesthesia and transfusion. Even after the recovery of patients from anesthesia V d /V t remained high and F e co 2 decreased in the SF group. In contrast, V d /V t decreased almost to normal and F e co 2 remained normal in the DWF group. Fraction of physiological shunt Qs/Qt tended to decrease after anesthesia and transfusion either in the SF or DWF group. The ventilation‐perfusion ratio increased relatively more markedly and pHa elevated definitely in the SF group after transfusion. The above data indicate that microembolism occurs after transfusion of stored blood, even in an amount of 1,000 ml, with a standard nylon mesh filter and concealed pulmonary dysfunction is observable. Therefore, a fine filter, such as a dacron wool filter or a polyester mesh filter, is recommended to avoid the pulmonary microembolism and the consequent respiratory distress following the transfusion of stored blood.