Reduction in red blood cell transfusions using a bedside analyzer in extremely low birth weight infants

Preterm infants typically experience heavy phlebotomy losses from frequent laboratory testing in the first few weeks of life. This results in anemia, requiring red blood cell (RBC) transfusions. We recently introduced a bedside point-of-care (POC) blood gas analyzer (iSTAT, Princeton, NJ) that requires a smaller volume of blood to replace conventional Radiometer blood gas and electrolyte analysis used by our neonatal intensive care unit (NICU). The smaller volume of blood required for sampling (100 vs 300-500 microl), provided an opportunity to assess if a decrease in phlebotomy loss occurred and, if so, to determine if this resulted in decreased transfusions administered to extremely low birth weight (ELBW) infants.

We hypothesized that the use of the POC iSTAT analyzer that measures pH, PCO(2), PO(2), hemoglobin, hematocrit, serum sodium, serum potassium and ionized calcium would result in a significant decrease in the number and volume of RBC transfusions in the first 2 weeks of life.

A retrospective chart review was conducted of all inborn premature infants with birth weights less than 1000 g admitted to the NICU that survived for 2 weeks of age during two separate 1-year periods. Blood gas analysis was performed by conventional laboratory methods during the first period (designated Pre-POC testing) and by the iSTAT POC device during the second period (designated post-POC testing). Data collected for individual infants included the number of RBC transfusions, volume of RBCs transfused, and the number and kind of blood testing done. There was no effort to change either the RBC transfusion criteria applied or blood testing practices.

The mean (+/-SD) number of RBC transfusions administered in the first 2 weeks after birth was 5.7+/-3.74 (n=46) in the pre-POC testing period to 3.1+/-2.07 (n=34) in the post-POC testing period (p<0.001), a 46% reduction. The mean volume of RBC transfusions decreased by 43% with use of the POC analyzer, that is, from 78.4+/-51.6 ml/kg in the pre-POC testing group to 44.4+/-32.9 ml/kg in the Post-POC testing group (p<0.002). There was no difference between the two periods in the total number of laboratory blood tests done.

Use of a bedside blood gas analyzer is associated with clinically important reductions in RBC transfusions in the ELBW infant during the first two weeks of life.