Venoarterial extra corporeal membrane oxygenation and blood component usage in pediatric patients undergoing cardiac surgery: Single centre experience

Background

Extra Corporeal Membrane Oxygenation (ECMO) is a well-known tool for providing life-saving support in patients developing post cardiotomy cardiogenic shock in post cardiac surgeries. The current study was designed to evaluate blood transfusion requirements and its relation to mortality in neonate and pediatric cardiac patients requiring venoarterial cardiac ECMO during post-operative period following cardiac surgery.

Materials and Methods

Overall 24 pediatric patients (including neonates) who underwent VA ECMO in post cardiac surgery at our institute from January 2016 to October 2017 were included in the study. The details of demographics, blood transfusion, ECMO, and morbidity and mortality were collected for all the patients.

Objective of the Study

The primary objective of our study was to assess the outcome of patients on ECMO in post pediatric cardiac surgery. The secondary objective of the study was to assess the effect of blood transfusion on the outcome of the patients.

Results

Overall mortality rate was 50% (n = 12). The overall transfusion rate of packed red blood cells was higher in patients who did not survive even after institution of VA ECMO. The transfusion of other blood products like platelets, cryoprecipitate, and fresh frozen plasma were also higher in this group of patients though it was statistically non-significant except for packed red cell transfusion. Though statistically non-significant, the patients who didn't survive even after institution of VA ECMO post-surgery had relatively higher mean age (703.88 ± 998.94 days) as compared to their counterparts (510.63 ± 384.36 days).

Conclusion

The use of ECMO is associated with considerable morbidity and mortality. Packed red cell transfusion is definitely higher in expired patients, indicative of deteriorated status of the patient. However, considering non-significant association of other blood components, except packed red cell it is recommended that patients' overall clinical condition should be taken into consideration for transfusion of blood products and not only targeting the transfusion triggers.

Impact of carbon dioxide tension during cardiopulmonary bypass on tissue perfusion in neonates undergoing cardiac surgery using autologous umbilical cord blood

Objective:

Previously, we reported that the oxyhemoglobin dissociation curve is shifted leftward in patients who receive autologous umbilical cord blood (UCB) during neonatal open heart surgery. In this study, we assessed whether allowing the pCO2 to rise during hypothermic cardiopulmonary perfusion would shift the curve back to the right and improve tissue oxygenation.

Methods:

The study population included prenatally diagnosed patients with transposition of the great arteries. The study cohort was divided into two groups and consisted of early patients originally managed with lower pCO2 levels (Group I, n=42, 2009-12) and later patients subsequently managed with higher pCO2 levels (Group II, n=38, 2012-14).

Results:

Patients received similar volumes of collected autologous UCB (Group I, 80 ml; Group II, 75ml, p=0.207) with a similar mean level of HbF during CPB (Group I, 90±8%; Group II, 87±9%, p=0.310). Higher levels of pCO2 during CPB (Group I, 31 mmHg; Group II, 37 mmHg, p=0.011) resulted in a rightward shift of the oxyhemoglobin dissociation curve (increased p50O2) (Group I, 19.5±3.4 mmHg; Group II, 22.5±2.2 mmHg, p=0.011). The use of a higher pCO2 strategy was associated with decreased serum lactate during CPB (Group I, 4.7±2 mmol/l; Group II, 2.8±1.4 mmol/l, p=0.001), decreased duration of mechanical ventilation (Group I, 46h; Group II, 22h, p<0.001) and decreased of length of intensive care unit (ICU) stay (Group I, 7.6±2.6, Group II, 5.6±2.2, p=0.003)

Conclusions:

A higher pCO2 during CPB in neonates who underwent open heart surgery using UCB resulted in a rightward shift of the oxyhemoglobin dissociation curve and was associated with improved serum lactate levels.

Blood Component Usage during Extracorporeal Membrane Oxygenation: Experience in 98 Patients at a Latin-American Tertiary Hospital

Background/Aims

Hemorrhagic complications during ECMO may affect a large proportion of the patients depending on the clinical setting. To guarantee optimal delivery of blood products to these patients, blood banks require updated information on the transfusion requirements. Few studies to date provide this information. This work assesses transfusion requirements in neonates and children during ECMO during the past 9 years.

Methods

We reviewed blood bank and hospital records of patients who underwent ECMO at our institution between May 2003 and May 2012. Data obtained included age, weight, diagnosis, type, length of ECMO, and daily transfusion requirements during ECMO. Descriptive and non-parametric inferential statistic analyses were performed. Our series included 98 patients.

Results

Mean time of patients on ECMO was 9.2 days, with the longest treatment spanning 22 days. Mean daily transfusion requirements were 39.5 ml/kg of RBC, 12.9 ml/kg of plasma, 34.3 ml/kg of platelets and 1.4 ml/kg of cryoprecipitate. Patients who underwent ECMO due to cardiac disease or congenital diaphragmatic hernia (CDH) required significantly higher transfusion volumes of plasma (p<0.05), platelets (p< 0.05) and cryoprecipitate (p<0.05) when compared to patients underwent ECMO due to respiratory disease. Concomitant with the aging of ECMO circuits, patients showed increased requirements of RBC, plasma, and CRYO around the seventh day of the ECMO run. This effect was not observed for platelets, which remained nearly consistent around 2.2 transfusions/day.

Conclusions

ECMO patients required significant transfusion support, which was particularly higher among patients who underwent ECMO due to cardiac disease or congenital diaphragmatic hernia.

Performance and scaling effects in a multilayer microfluidic extracorporeal lung oxygenation device

Microfluidic fabrication technologies are emerging as viable platforms for extracorporeal lung assist devices and oxygenators for cardiac surgical support and critical care medicine, based in part on their ability to more closely mimic the architecture of the human vasculature than existing technologies. In comparison with current hollow fiber oxygenator technologies, microfluidic systems have more physiologically-representative blood flow paths, smaller cross section blood conduits and thinner gas transfer membranes. These features can enable smaller device sizes and a reduced blood volume in the oxygenator, enhanced gas transfer efficiencies, and may also reduce the tendency for clotting in the system. Several critical issues need to be addressed in order to advance this technology from its current state and implement it in an organ-scale device for clinical use. Here we report on the design, fabrication and characterization of multilayer microfluidic oxygenators, investigating scaling effects associated with fluid mechanical resistance, oxygen transfer efficiencies, and other parameters in multilayer devices. Important parameters such as the fluidic resistance of interconnects are shown to become more predominant as devices are scaled towards many layers, while other effects such as membrane distensibility become less significant. The present study also probes the relationship between blood channel depth and membrane thickness on oxygen transfer, as well as the rate of oxygen transfer on the number of layers in the device. These results contribute to our understanding of the complexity involved in designing three-dimensional microfluidic oxygenators for clinical applications.