Effects of red cell transfusion on pulmonary blood flow and right ventricular systolic time intervals in neonates.

UNLABELLED

Blood transfusion increases blood volume and blood viscosity of the neonate. Since both volume expansion and increase in blood viscosity may be associated with increased pulmonary artery pressure, we studied effects of transfusion (10 ml of red blood cells per kilogramme of body weight) on right ventricular output and right systolic time intervals by means of pulsed-Doppler echocardiography in 38 preterm infants with a mean (SD) gestational age of 28 (5) weeks (range 25-34), birth weight 1060 (395) g (range 480-1910), actual body weight 1875 (450) g (range 820-2790) and postnatal age of 44 (23) days (range 17-105). After transfusion, packed cell volume and haemoglobin increased significantly from 0.26 (0.044) to 0.38 (0.046), and from 8.2 (1.6) g/l to 12.8 (1.9), respectively. Blood viscosity increased from 1.78 (0.3) mPa to 2.68 (0.4) by 33%. Right ventricular output decreased significantly from 320 (57) ml/kg/min to 290 (70) due to decrease in heart rate by 7%. Blood pressure and right ventricular stroke volume did not change. There was a significant increase in pulmonary red cell transport (right ventricular output times packed cell volume) of 21%. Right ventricular pre-ejection period (RPEP), right time peak velocity (RTPV), right ventricular ejection time (RVET), and ratios of RTPV/RVET(c). RPEP:RVET did not change after transfusion.

CONCLUSIONS

These results suggest that neither pulmonary artery pressure nor right ventricular function changed as a result of transfusion in spite of rising blood volume and blood viscosity.