The effect of red blood cell transfusion on intermittent hypoxemia in ELBW infants

Abstract

Objective: To test the hypothesis that the effect of red blood cell (RBC) transfusion on intermittent hypoxemia (IH) in extremely low birth weight (ELBW) infants is dependent on postnatal age.

Study design: Oxygen saturation of 130 ELBW infants, who required transfusion, was monitored continuously for the first 8 weeks of life. We compared the characteristics of IH (SpO2⩽80% for ⩾4 s and ⩽3 min), 24 h before and both 24 h and 24 to 48 h after each RBC transfusion at three distinct time periods: Epoch 1, 1 to 7 days; Epoch 2, 8 to 28 days; and Epoch 3, >28 days.

Result: In Epoch 1, the frequency and severity of IH events were not significantly different before and after transfusion. In both Epochs 2 and 3 there was a decrease in IH frequency and severity 24 h after RBC transfusion that persisted for 48 h. In addition, there was a decrease in the overall time spent with SpO2 ⩽80% which persisted for 24 h after transfusion in Epochs 1 and 3, and for 48 h in Epoch 3.

Conclusion: The benefit of RBC transfusion on IH is age dependent as improvement in the frequency and severity of IH after transfusion only occurs beyond the first week of life. These observations will aid clinician's decision making by clarifying the benefit of RBC transfusions on patterns of oxygenation in preterm infants.

Figure 1

The frequency of intermittent hypoxemia (IH) events during the first 8wks of postnatal life. The 8wk postnatal period was stratified into 3 epochs. Epoch 1 was defined as 1-7d of life, Epoch 2 between 8 – 28d of life, Epoch 3 after 28d of life.

Figure 2

Hematocrit data presented in box-and-whisker diagram. There was no difference in pre and post RBC transfusion hematocrit level across epochs. There was a significant increase in the hematocrit level post RBC transfusion in all three epochs (*p<0.001). Box plot represent median and interquartile ranges. Whiskers represent the hematocrit range (minimum – maximum).

Figure 3

Characteristics of IH pre and post RBC transfusion including (A) frequency, (B) nadir, and (C) duration. Frequency significantly decreased and IH nadir increased at 24h and 24-48h post RBC transfusion only in Epochs 2 and 3 (*p<0.02 versus pre RBC transfusion). There was no change in IH duration.

Figure 4

Percent time with SpO₂ < 80% pre and post RBC transfusion. The percent time with SpO₂ ≤ 80% significantly decreased in Epochs 1 and 3 at 24h post RBC transfusion persisting for 24-48h in Epoch 3 (*p<0.05). There was a trend towards a decrease in time with SpO₂ ≤ 80% in Epoch 2 that did not reach statistical significance (^‡p=0.058).