Mercury, lead, and cadmium exposure via red blood cell transfusions in preterm infants

Fetal exposure to toxic metals (mercury, cadmium, lead, and arsenic) via intrauterine blood transfusions

BACKGROUND

Intrauterine blood transfusions (IUBTs) are critical for treating fetal anemia but may expose fetuses to toxic metals. This study assessed mercury (Hg), cadmium (Cd), lead (Pb), and arsenic (As) levels in red blood cell (RBC) transfusion bags used during pregnancy, examined metal exposure in maternal and cord blood, and evaluated fetal health risks.

METHODS

Thirty pregnant women who underwent intrauterine blood IUBTs were enrolled in this study. Metal concentrations were measured in one to nine transfusion bags for each participant. These bags contained 8-103 mL volumes and were administered between gestational weeks 18 and 35. We also tested the mothers' blood for metal levels in the final stages of pregnancy and the umbilical cord blood at birth. The assessment utilized the intravenous reference dose (IVRfD) and the hazard index (HI) to evaluate the non-carcinogenic health risks these metals might pose to the fetus.

RESULTS

Metals were detectable in almost all transfusion bags. The IVRfD was exceeded for Hg in 16 fetuses, Cd in 8 fetuses, Pb in 30 fetuses, and As in 1 fetus. Significant correlations were found between the concentrations of Hg, Cd, and As in transfused RBCs and cord blood. No correlations were observed between these concentrations and maternal blood levels, except for Cd. The influence of multiple IUBTs was positively associated only with Cd levels in the cord (ß = 0.529, 95% confidence intervals (CI) between 0.180 and 0.879). The HI exceeded 1, indicating significant health risks, predominantly from Pb, followed by Hg and Cd.

CONCLUSION

The findings of this study highlight the significant risk of fetal exposure to toxic metals, mainly Pb, through IUBTs. This underscores the critical need for prescreening blood donors for toxic metals to minimize the potential for long-term adverse effects on the fetus. The research stresses the necessity of balancing the immediate benefits of IUBTs against the risks of toxic metal exposure, underscoring the importance of safeguarding fetal health through improved screening practices.

IMPACT

This study highlights the risk of toxic metal exposure through IUBTs, a treatment for fetal anemia. Hg, Cd, Pb, and As levels were measured in transfusion bags and linked to fetal exposure through maternal and umbilical cord blood analysis. The HI indicates significant Pb exposure risks, underscoring the need for mandatory blood donor screening. Recommendations include shifting toward safer practices in managing fetal anemia to protect fetal health.

Encouraging results of blood conservation in neonatal open-heart surgery

OBJECTIVE

To report early outcomes of blood conservation in neonatal open-heart surgery.

METHODS

Ninety-nine patients undergoing neonatal open-heart surgery during the implementation of a blood conservation program between May 2021 and February 2023 were reviewed. Patients either received traditional blood management (blood prime, n = 43) or received blood conservation strategies (clear prime, n = 56). Baseline characteristics and outcomes were compared between groups.

RESULTS

There was no difference in body weight (median, 3.2 kg vs 3.3 kg; P = .83), age at surgery (median, 5 days vs 5 days; P = .37), distribution of The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery Congenital Heart Surgery Mortality Categories categories or duration of cardiopulmonary bypass. Patients in the clear prime group had higher preoperative hematocrit (median, 41% vs 38%; P < .01), shorter postoperative mechanical ventilation time (median, 48 hours vs 92 hours; P = .02) and postoperative intensive care unit length of stay (median, 6 days vs 9 days; P < .01) than patients in the blood prime group. Fourteen patients (25%) in the clear prime group, including 1 Norwood patient, were discharged without any transfusion. Among patients within the clear prime group, hospitalizations without blood exposure were associated with higher preoperative hematocrit (median, 43% vs 40%; P = .02), shorter postoperative mechanical ventilation times (median, 22 hours vs 66 hours; P = .01) and shorter postoperative hospital stays (median, 10 days vs 15 days; P = .02).

CONCLUSIONS

Bloodless surgery is possible in a significant proportion of neonates undergoing open-heart surgery, including the Norwood operation, even in the early stages of experience. Early clinical results are favorable but long-term follow-up and continued efforts are warranted to prove safety and reproducibility.

New frontiers in neonatal red blood cell transfusion research

Red blood cell (RBC) transfusions are common in neonates requiring intensive care. Recent studies have compared restricted versus liberal transfusion guidelines, but limitations exist on evaluations of outcomes in populations that never required a transfusion compared to those receiving any transfusion. Although there are well-established risks associated with RBC transfusions, new data has emerged that suggests additional clinically relevant associations, including adverse neurodevelopmental outcomes, donor sex differences, and inflammation or immunosuppression. Further research is needed to delineate the magnitude of these risks and to further improve the safety of transfusions. The goal of this review is to highlight underappreciated, yet clinically important risks associated with neonatal RBC transfusions and to introduce several areas in which neonates may uniquely benefit from alterations in practice.

Lead, Mercury, and Cadmium Concentrations in Blood Products Transfused to Neonates: Elimination Not Just Mitigation

Lead (Pb), mercury (Hg), and cadmium (Cd) are identified as potent developmental neurotoxicants. Neonates are the main group receiving multiple blood transfusions. The exposure of neonates to these heavy metals (HMs) can occur through blood transfusions. This study aimed to determine the concentrations of lead (Pb), mercury (Hg), and cadmium (Cd) in various blood products (plasma, platelets, packed red blood cells (pRBCs), and whole blood (WB)) to explore the probability of concurrent exposure of these HMs and to identify the metal load per transfusion with risk assessment. Residual bloods from blood bank bags were collected after neonatal transfusion. Pb, Hg, and Cd concentrations were determined in 120 samples of blood products by inductively coupled plasma mass spectrometry (ICP-MS). Pb and Cd levels were over the normal levels in 19.2 and 5.9% of all blood units, respectively. In 35 and 0.8% of blood units, the Pb and Cd concentrations, respectively, were higher than that recommended for transfusions in premature neonates. The anticipated safe value was surpassed by 2.5% for Cd of all transfusions, primarily because of WB. However, Hg was detected only in 5.8% of all samples and their concentrations were within the normal range. The concurrent neonatal exposure to Pb, Hg, and Cd was statistically significant. Hazard quotients of Hg and Cr were >1 and Pb cancer risk was 2.41 × 10-4. To the best of our knowledge, this study is the first report examining Pb, Hg, and Cd in blood products other than WB and pRBCs using ICP-MS. This study demonstrated the exposure of neonates to Pb, Hg, and Cd during transfusion with a considerable amount of Pb. It confirms the significant concurrent exposure to the three HMs, which maximize their potential developmental neurotoxicity with a high probability of developing non-carcinogenic and carcinogenic health effects.

Exposure of preterm neonates to toxic metals during their stay in the Neonatal Intensive Care Unit and its impact on neurodevelopment at 2 months of age

BACKGROUND

Premature neonates might be exposed to toxic metals during their stay in the neonatal intensive care unit (NICU), which could adversely affect neurodevelopment; however, limited evidence is available. The present study was therefore designed to assess the exposure to mercury, lead, cadmium, arsenic, and manganese of preterm neonates who received total parenteral nutrition (TPN) and/or red blood cell (RBC) transfusions during their NICU stay and the risk of neurodevelopment delay at the age of 2 months.

METHODS

We recruited 33 preterm neonates who required TPN during their NICU admission. Blood samples were collected for metal analysis at two different time points (admission and before discharge). Metals in the daily TPN received by preterm neonates were analyzed. Neurodevelopment was assessed using the Ages and Stages Questionnaire Edition 3 (ASQ-3).

RESULTS

All samples of TPN had metal contamination: 96% exceeded the critical arsenic limit (0.3 μg/kg body weight/day); daily manganese intake from TPN for preterm neonates exceeded the recommended dose (1 µg/kg body weight) as it was added intentionally to TPN solutions, raising potential safety concerns. All samples of RBC transfusions exceeded the estimated intravenous reference dose for lead (0.19 µg/kg body weight). Levels of mercury, lead and manganese in preterm neonates at discharge decreased 0.867 µg/L (95% CI, 0.76, 0.988), 0.831 (95%CI, 0.779, 0.886) and 0.847 µg/L (95% CI, 0.775, 0.926), respectively. A decrease in ASQ-3-problem solving scores was associated with higher levels of blood lead in preterm neonates taken at admission (ß = -0.405, 95%CI = -0.655, -0.014), and with plasma manganese (ß = -0.562, 95%CI = -0.995, -0.172). We also observed an association between decreased personal social domain scores with higher blood lead levels of preterm neonates before discharge (ß = -0.537, 95%CI = -0.905, -0.045).

CONCLUSION

Our findings provide evidence to suggest negative impacts on the neurodevelopment at 2 months of preterm infants exposed to certain metals, possibly related to TPN intake and/or blood transfusions received during their NICU stay. Preterm neonates may be exposed to levels of metals in utero.