Factors Associated with Blood Loss and Blood Product Transfusions

Cardiopulmonary bypass-induced coagulopathy in pediatric patients: The role of platelets in postoperative bleeding. A preliminary study

Pediatric patients are particularly prone to cardiopulmonary bypass (CPB)-induced coagulopathy mainly due to hemodilution, consumption of coagulation factors and hypothermia. The aim of the present study was to examine the possible role of platelet count and function as it relates to the bleeding risk after CPB in the pediatric population. All consecutive patients (age <13 years) scheduled for elective cardiac surgery between January 2019 and November 2019 were retrospectively considered for the study. We gathered demographic characteristics, perioperative laboratory data (mainly platelet count and function), transfusion requirements, and blood loss for each patient. Patients with a chest tube output during the first 24 hours after surgery >75th percentile were bleeders (cases). Controls were nonbleeders. A total of 31 patients were enrolled [median age 17 (4-57) months]. A significant postoperative reduction in platelet count (P < .001) and function either in ADP-test (P < .001), TRAP-test (P < .001) and ASPI-test (P < .001) was found, with positive correlations between chest tube output within the first 24 hours after surgery and postoperative impairment of platelet count (R = 0.553, P = .001), ADP-test (R = 0.543, P = .001), TRAP-test (R = 0.627, P < .001) and ASPI-test (R = 0.436, P = .014). Eight children (26%) experienced major postoperative bleeding. Bleeders were significantly younger (P = .015) and underwent longer CPB duration (P = .015). Despite no significant differences in postoperative platelet count and function between cases and controls, the postoperative reduction (Δ) in platelet count (P = .002) and function in ADP-test (P = .007), TRAP-test (P = .020) and ASPI-test (P = .042) was significantly greater in bleeders vs. nonbleeders. A ΔPLT >262 500 ×10⁹ /L, a ΔADP-test >29 U, a ΔTRAP-test >44 U and a ΔASPI-test >26 U showed to be predictive of major postoperative bleeding. Postoperative bleeding in children undergoing cardiac surgery with CPB was linked to younger age, longer CPB duration, and significant postoperative reduction in platelet count and function. Larger studies are needed to confirm our results and define strategies to reduce postoperative bleeding in these patients.

Bleeding in Critically Ill Children-Review of Literature, Knowledge Gaps, and Suggestions for Future Investigation

Clinically significant bleeding complicates up to 20% of admissions to the intensive care unit in adults and is associated with severe physiologic derangements, requirement for significant interventions and worse outcome. There is a paucity of published data on bleeding in critically ill children. In this manuscript, we will provide an overview of the epidemiology and characteristics of bleeding in critically ill children, address the association between bleeding and clinical outcomes, describe the current definitions of bleeding and their respective limitations, and finally provide an overview of current knowledge gaps and suggested areas for future research.

Cardiopulmonary Bypass Reduces Early Thrombosis of Systemic-to-Pulmonary Artery Shunts

BACKGROUND

Shunt thrombosis is a significant cause of morbidity and mortality after systemic-to-pulmonary artery shunt (SPS) placement. Concurrent procedures with placement of SPS may require cardiopulmonary bypass (CPB). Cardiopulmonary bypass is known to cause bleeding and platelet dysfunction in infants, which may protect from early shunt thrombosis. We hypothesized that infants undergoing SPS placement on CPB have a lower incidence of early shunt thrombosis.

METHODS

Retrospective cohort study of infants undergoing SPS placement from January 2008 to December 2014 was performed. Patients with and without early shunt thrombosis and on or off CPB were compared using the Mann-Whitney U test or Fisher exact test. Multivariable regression analysis was performed to identify independent predictors of early shunt thrombosis and to assess effect of CPB independent of other factors.

RESULTS

Seventy-five infants underwent SPS placement during the study period (on CPB, n = 25; off CPB, n = 50). Operative mortality was 11% (8/75). Nine (12%) patients developed early shunt thrombosis, all of whom had shunt placement off CPB. Independent risk factors for early shunt thrombosis were identified to be SPS placement off CPB ( P = .011), prematurity ( P = .034), and competitive antegrade pulmonary blood flow ( P = .038).

CONCLUSION

Prematurity, competitive antegrade pulmonary blood flow, and shunt placement off CPB lead to higher risk of early shunt thrombosis. We speculate that the protection offered by use of CPB may be accounted for by the associated complex coagulopathy and platelet dysfunction associated with CPB.

High-dose aprotinin, blood product transfusions, and short-term outcome in neonates and infants: a pediatric cardiac surgery center experience

BACKGROUND

The efficacy of aprotinin, the most popular antifibrinolytic agent in congenital cardiac surgery, was still uncertain in small infants when its prophylactic use was suspended for safety reasons. The aim of this study is to describe associations between the prophylactic use of high-dose aprotinin, the need for blood product transfusions, and short-term outcome in neonates and infants with cardiac surgery.

METHODS/MATERIALS

This retrospective study included all patients younger than 1 year undergoing surgery with cardiopulmonary bypass through 42 months, before and after withdrawal of aprotinin. Each patient who received aprotinin was matched with a control with similar baseline and surgical characteristics, who have not received any antifibrinolytic agent. Associations between the use of aprotinin and the exposure to red blood cells, fresh frozen plasma, and platelet transfusions were estimated from a logistic regression model, and the exposure to additional transfusions from a polytomous regression model.

RESULTS

Matching resulted in two groups of 283 patients each, well balanced except for the priming volume and the ultrafiltration rate, larger in the aprotinin group. After adjustment for the priming volume and ultrafiltration rate, there was no significant association between the use of aprotinin, the exposure to any blood product transfusion, or the exposure to additional transfusions, the rate of re-exploration for bleeding, and short-term outcome. Two patients in the control group required re-exploration for bleeding.

CONCLUSIONS

No association was found between the prophylactic use of aprotinin, blood product transfusions, and short-term outcome in this population of neonates and infants.

Pediatric resuscitation in the operating room

The resuscitation of pediatric patients undergoing anesthesia involves appropriate administration of fluid and blood products and stabilization of vital signs. Crystalloid is first-line therapy for fluid resuscitation, and should be given with awareness of its potential dilution of the child's hematocrit. Many alternatives to homologous blood transfusions now exist, however, when necessary for increasing oxygen-carrying capacity or treating coagulopathy benefits likely outweight the risks. The risks for such transfusion include infectious, hemolytic, metabolic, and immunologic effects. When fluid and blood administration does not stabilize the patient, the differential diagnosis of hypotension, arrest, or arrhythmias must include medication errors, anesthetic overdose, electrolyte disturbances, hypoxemia, ventilatory problems, and surgical insults, including medications given in the operative field. Resuscitation should include treatment of hypocalcemia and hyperkalemia, chest compressions, and the administration of epinephrine when necessary.