Functional echocardiographic assessment of myocardial performance in anemic premature infants: a pilot study

The impact of a PDA on tissue oxygenation and haemodynamics following a blood transfusion in preterm infants

BACKGROUND

To examine the impact of PRBC transfusion on pulmonary vascular resistance (PVR), systemic vascular resistance and myocardial function using echocardiography and cerebral and splanchnic tissue oxygenation using near-infrared spectroscopy (NIRS) in premature babies with and without a PDA.

METHODS

A prospective observational study of premature infants born <1500 g in receipt of PRBC transfusions beyond 10 days of age. Echocardiography and NIRS monitoring were performed at baseline, during the transfusion and 24 h after transfusion.

RESULTS

Thirty infants with a median gestation of 26.4 [24.8-28.0] weeks were enrolled. Ten infants had a PDA. Following transfusion, a significant decrease in PVR markers occurred in all infants. Right ventricular (RV) function increased following transfusion in the PDA closed group only. Cerebral oxygen saturation increased following transfusion in all infants. Babies in the PDA open group had significantly lower splanchnic oxygen saturations at baseline compared to the PDA closed group which persisted over the study period and were unaltered by transfusion.

CONCLUSIONS

PRBC transfusion lowers PVR irrespective of PDA status. Those with a PDA demonstrated a lack of improvement in RV function and splanchnic oxygenation highlighting the impact a PDA has on the neonatal circulation.

IMPACT

The presence or absence of the PDA imposes differential effects on splanchnic oxygenation during red blood cell (PRBC) transfusion in the premature population. This is the first study to assess the impact of the PDA on splanchnic oxygenation via near-infrared spectroscopy (NIRS) during red blood cell transfusion in premature neonates. New insights have been found into the impact of PRBC transfusion on pulmonary vascular resistance, right ventricular function, cerebral and splanchnic oxygenation in the presence and absence of a PDA and emphasises the ongoing impact of ductal patency on gut oxygenation.

Regional Oxygenation and Perfusion Monitoring to Optimize Neonatal Packed Red Blood Cell Transfusion Practices: A Systematic Review

Contemporary packed red blood cell transfusion practices in anaemic preterm infants are primarily based on measurement of hemoglobin or haematocrit. In neonatal intensive care units, most preterm infants receive at least 1 packed red cell transfusion as standard treatment for anaemia of prematurity. Clinicians are faced with a common question "at what threshold should anaemic preterm infants receive packed red blood cell transfusion?". While evidence from interventional trials offers a range of haemoglobin levels to clinicians on thresholds to initiate red cell transfusion, it does not offer identification of exact haemoglobin level at which regional oxygenation and perfusion gets compromised. Assessment of regional oxygenation using near infrared spectroscopy and perfusion using ultrasound could offer a personalized transfusion medicine approach to optimize transfusion practices. We conducted a systematic review of the literature to identify the role of both regional oxygenation and/or ultrasound-based perfusion monitoring as a potential trigger to initiate packed red blood cell transfusion in anaemic preterm infants. MEDLINE, Embase, Maternity and Infant Care database were searched up to March 2021. Publications identified were screened and relevant data was extracted. Changes to regional oxygenation and/or perfusion monitoring before and after packed red blood cell transfusion were the primary outcomes. 44 out of 755 studies met the inclusion criteria and were included in the final analysis. Most were prospective, observational studies in stable preterm infants. Overall, studies reported an improvement in regional oxygenation and/or ultrasound-based perfusion after packed red blood cell transfusion. These changes were more consistently observed when hemoglobin <9.6g/dL or hematocrit was <0.30. Significant variation was found for patient characteristics, postnatal age at the time of monitoring, criteria for diagnosis of anaemia, and period of monitoring as well as regional oxygenation monitoring methodology. Regional oxygenation and/or perfusion monitoring can identify at-risk anaemic preterm infants and are promising tools to individualize packed red blood cell transfusion practices. However, there is lack of evidence for incorporating this monitoring, in their present form, into standard clinical practice. Additionally, consistency in reporting of study methodology should be improved.

Hemodynamics of different volumes of red blood cell transfusion in preterm infants

BACKGROUND

Although many controversies exist regarding the risk of red blood cell (RBC) transfusions, half of preterm infants born at <32 weeks of gestational age receive such transfusions because of anemia of prematurity. Because of the costs and risks associated with multiple transfusions, it has been suggested that a large transfusion volume reduces the number of transfusions. However, there have been persistent concerns that RBC transfusion might lead to volume overload.

METHODS

We examined the impacts of large (20 mL/kg) compared to standard volume (15 mL/kg) transfusions on the hemodynamic variables of stable, electively transfused, preterm infants, by serially measuring echocardiographic parameters and plasma B-type natriuretic peptide levels.

RESULTS

A total of 39 infants born at <34 weeks of gestation and aged >2 weeks at the time of enrollment were randomly allocated to either a standard volume (15 mL/kg) or a large volume (20 mL/kg) group. Significant reductions in cardiac output and transient increases in plasma B-type natriuretic peptide levels were found after RBC transfusion in both the standard and large volume (20 mL/kg) groups. However, these changes were not significantly different between the two groups.

CONCLUSIONS

Large-volume transfusions could be tolerable in stable preterm infants with anemia.

Hemodynamics and Perfusion in Premature Infants During Transfusion

BACKGROUND

Premature infants may require packed red blood cell transfusions, but current guidelines lack empirical evidence and vary among institutions and prescribers.

OBJECTIVE

To compare the physiological changes in cardiovascular hemodynamics and oxygen delivery between premature infants with anemia who receive packed red blood cell transfusions and premature infants without anemia.

METHODS

The study was a prospective observational cohort investigation of 75 premature infants. Comparisons among the data were made before, during, and after transfusion in infants with anemia and over time in infants in the control group. In infants with anemia, feedings were withheld 12 hours before and after transfusions.

RESULTS

Electrical cardiometry and near-infrared spectroscopy measurements in premature infants with anemia revealed changes in hemodynamic parameters not detected by standard bedside monitoring. Statistically significant changes were seen before and after transfusions in cardiac output, fractional tissue oxygen extraction, heart rate variability, heart rate complexity, and splanchnic regional tissue oxygen saturation.

CONCLUSION

Bedside monitoring of cardiovascular hemodynamics and oxygen delivery during packed red blood cell transfusion may inform individualized care for the premature infant with anemia and could be useful for the development of evidence-based practice guidelines.

Association between anemia and packed cell transfusion and outcomes of ventricular septal defect and atrioventricular canal repair in children

Data on the prevalence and impact of anemia and packed red blood cell (PRBC) transfusions in children with congenital heart disease are limited. Our objectives were to determine the prevalence of anemia and its impact and the impact of PRBC transfusion in the initial 5 days after surgical repair on postoperative outcomes in infants with ventricular septal defect (VSD) and atrioventricular (AV) canal. Retrospective chart review of infants (1 year old) (n = 195) with AV canal or VSD who underwent surgical repair at Children's Hospital of Michigan during a 10-year period. Statistical analyses (SPSS 17.0) included Chi square and Student t test as well as regression analysis with significance set at p = 0.05. Preoperative anemia was diagnosed in 45 of 195 (23%) children. Anemic infants had VSD more frequently (80%), significantly shorter bypass and cross-clamp durations, and higher red cell distribution widths. Postoperative outcomes and PRBC transfusions were similar in the groups. On regression analysis, AV canal was associated with a significantly lower (odds ratio 0.21; 95% confidence interval 0.07-0.68, p = 0.009) risk of anemia. Infants who received a PRBC transfusion (n = 42) had significantly lower birth weights as well as weights at surgery and longer postoperative durations of pressor use, ventilation, oxygen supplementation, and length of stay than those who did not (n = 153) receive transfusions. PRBC transfusion was independently associated with longer postoperative length of stay, oxygen, pressor use, and ventilator duration. Approximately 23% of infants with AV canal or VSD are anemic. PRBC transfusions in the initial 5 postoperative days, but not anemia, are independently associated with adverse postoperative outcomes. Further studies to evaluate conservative transfusion strategies in this population are needed.

Myocardial assessment using tissue doppler imaging in preterm very low-birth weight infants before and after red blood cell transfusion

OBJECTIVE

To investigate myocardial velocities in anemic very low-birth weight (VLBW) preterm infants, pre and post red blood cells transfusion using tissue Doppler imaging echocardiography.

STUDY DESIGN

Forty-eight VLBW preterm infants34 weeks and>2 weeks old were prospectively divided: Transfused symptomatic infants (Hematocrit (Hct)<0.30 (n=32)) and non transfused asymptomatic controls (control 1, Hct >0.30 (n=9) and control 2, Hct <0.30 (n=7)). Echocardiography was performed before and 3-5 days after transfusion in the transfused, and the controls were studied at similar intervals. Non parametric tests were used for statistical analysis.

RESULT

Left ventricular (LV) systolic velocity increased (transfused (4.6±0.70 vs 6.0±0.65, P<0.01)) as did LV diastolic velocities (P<0.01) without significant difference over time in each control. The percentage change in LV velocity following transfusion correlated negatively (ρ=0.36) with pre transfusion Hct.

CONCLUSION

There is a significant increase in myocardial performance following transfusion, which is related to the severity of the anemia.