How to tackle bleeding and thrombosis in the newborn

Coagulation and the surgical neonate

Both coagulopathy and abnormal thrombosis can complicate the anesthetic and surgical management of neonatal patients; however, the patterns of bleeding and thrombosis in neonates differ from those in adults or older children. Severe coagulopathic bleeding most commonly occurs during heart surgery and almost certainly contributes to morbidity and mortality in this population. Such severe bleeding is rare during other surgery; the exception is babies presenting to the operating room with established coagulopathy secondary to severe sepsis. Alternatively, pathological thrombosis will mainly occur in association with indwelling vascular access devices or surgically created vascular shunts. There are important differences between the coagulation system in neonates and older patients. The implication of this is that therapies established in other patient groups will not be optimal for neonates without adaptation. While evidence from high-quality clinical trials is rarely available, an understanding of how coagulation in neonates differs can help to guide practice. This review will discuss important differences between the coagulation system of neonates and older patients and how these relate to newer models of coagulation. The emphasis will be on issues likely to impact on perioperative care. In particular, the management of severe bleeding, the manipulation of coagulation during heart surgery, and the management of coagulopathy in septic neonates will be discussed in detail.

The specific characteristics of DIC syndrome vary with different clinical settings in the newborn

Abstract Two hundred fourteen newborns with serious perinatal pathology (posthypoxic syndrome, sepsis, surgical intervention, etc.) were examined in progress, according to 27 parameters including coagulative, trombocitic, anti-coagulative and fibrinolitic parts of hemostasis system. It was proved, that neonatal disseminated intravascular coagulation (DIC) syndrome had different hemostasiological patterns, which were connected with the genesis: sepsis, surgical intervention or posthypoxic syndrome. Precise periods of DIC syndrome are not always presented in newborns. DIC syndrome with neonatal sepsis has two different patterns (overcompensated and decompensated). The manifestation of trombo-hemorrhagic disorders and their characteristics depend on the genesis of DIC syndrome (e.g. an infection process and hyperbilirubinemia can provide the appearance of hemorrhagic syndrome).

Thrombocytopenia in neonates and the risk of intraventricular hemorrhage: a retrospective cohort study

Background

The overall prevalence of thrombocytopenia in neonates admitted to neonatal intensive care units ranges from 22 to 35%. There are only a few small studies that outline the relationship between the severity of thrombocytopenia and the risk of bleeding. This makes it difficult to form an evidence-based threshold for platelet transfusions in neonatal patients. The aim of this study was to determine the prevalence of thrombocytopenia in a tertiary neonatal intensive care unit and to study the relation between thrombocytopenia and the risk of intraventricular hemorrhage (IVH).

Methods

We performed a retrospective cohort study of all patients with thrombocytopenia admitted to our neonatal tertiary care nursery between January 2006 and December 2008. Patients were divided into 4 groups according to the severity of thrombocytopenia: mild (100-149 × 10⁹/L), moderate (50-99 × 10⁹/L), severe (30-49 × 10⁹/L) or very severe (< 30 × 10⁹/L). The primary outcome was IVH ≥ grade 2. Pearson's chi-squared and Fischer's exact tests were used for categorical data. ANOVA, logistic regression analysis and multivariate linear regression were used for comparisons between groups and for confounding factors.

Results

The prevalence of thrombocytopenia was 27% (422/1569). Risk of IVH ≥ grade 2 was 12% (48/411) in neonates with versus 5% (40/844) in neonates without thrombocytopenia (p < 0.01). After multivariate linear regression analysis, risk of IVH ≥ grade 2 in the subgroups of thrombocytopenic infants was not significantly different (p = 0.3).

After logistic regression analysis the difference in mortality rate in neonates with and without thrombocytopenia was not significant (p = 0.4). Similarly, we found no difference in mortality rate in the subgroups of neonates with thrombocytopenia (p = 0.7).

Conclusion

Although IVH ≥ grade 2 occurs more often in neonates with thrombocytopenia, this relation is independent of the severity of thrombocytopenia. Prospective studies should be conducted to assess the true risk of hemorrhage depending on underlying conditions. Randomized controlled trials are urgently needed to determine a safe lower threshold for platelet transfusions.

Defining the role of recombinant activated factor VII in pediatric cardiac surgery: where should we go from here?

OBJECTIVES

Postoperative hemorrhage is a recognized complication of pediatric cardiac surgery. Both the immature coagulation system and increased susceptibility to hemodilution increase the likelihood of pediatric patients developing coagulopathy when compared with adult counterparts. Treatment options remain limited. Recombinant factor VII (rFVIIa) is a hemostatic agent increasingly used to reduce hemorrhage in other surgical settings, the role of which is unclear in this population. This article systematically reviews the published literature on the use of rFVIIa in pediatric cardiac surgery.

DATA SOURCES AND STUDY SELECTION

A systematic literature search identified reports of rFVIIa administration in pediatric patients undergoing cardiac surgery. Where possible, individual patient-specific data were extracted and pooled statistical analysis was performed.

DATA EXTRACTION AND SYNTHESIS

Twenty-nine articles reporting on the administration of rFVIIa to 169 patients were identified. rFVIIa has been administered to patients with predefined congenital abnormalities of hemostasis to arrest hemorrhage refractory to other interventions and prophylactically in the hope of reducing blood loss. Treatment regimens vary widely, in terms of both first and cumulative dose. Data on chest tube blood loss and two markers of coagulation were pooled and analyzed, and significant improvements were demonstrated. Mortality was 4.4% for the entire cohort but 20% of patients on extracorporeal membrane oxygenation suffered significant thromboembolic complications.

CONCLUSIONS

rFVIIa has an increasingly accepted role in the management of patients with congenital coagulopathies undergoing major surgery. However, randomized trials are required to define the role of rFVIIa as an adjunct to control major hemorrhage in the pediatric cardiac surgical population. Any future work must focus not only on benefits but also on patient safety, particularly, risk of morbid thromboembolic complication.