Evaluation and treatment of thrombocytopenia in the neonatal intensive care unit

The Prevalence and Associated Risk Factors for Neonatal Thrombocytopenia Among Newborns Admitted to the Neonatal Intensive Care Unit

Background Thrombocytopenia is the most prevalent hematological condition in neonates that develops in the neonatal intensive care unit (NICU). This set of illnesses is caused by either decreased platelet production due to placental insufficiency, increased platelet breakdown (consumption), or a combination of the two causes. Based on platelet count, it is defined as mild, moderate, or severe thrombocytopenia, with early and late onset. Purpose The purpose of this study is to determine the prevalence of thrombocytopenia and the factors that contribute to it in newborns hospitalized in the neonatal critical care unit at the Maternity and Children Hospital in Al Ahsa, Saudi Arabia. Methods This descriptive retrospective cross-sectional study was carried out at the NICU of the Maternity and Children Hospital in Al Ahsa, Saudi Arabia, over the span of one year (August 2022 to August 2023) among hospitalized neonates with thrombocytopenia. Thrombocytopenia is defined as a platelet count of 150,000 or less. These patients were monitored until they recovered or died. Results The inclusion criteria were met by a total of 242 newborns with thrombocytopenia. Half of the neonates (57%) were full-term, with Apgar scores greater than 5 at the first (84%) and fifth (93%) minutes, respectively. The great majority of individuals (84%) experienced early-onset thrombocytopenia of mild severity (62%) and were asymptomatic (93%). The majority of the cases resolved spontaneously, with only 21% requiring platelet transfusion. There was a significant relationship discovered between gestational age and the severity of thrombocytopenia, with very preterm infants having moderate to severe thrombocytopenia, as well as birth weight (p=0.001). Furthermore, neonates with severe thrombocytopenia had a considerably higher mortality rate (p=0.001). Conclusion The mortality and morbidity of newborns with perinatal risk for neonatal thrombocytopenia can be reduced with timely detection of the cause and development of thrombocytopenia, as well as adequate and early care.

Assessment of Hemostatic Profile in Neonates with Intrauterine Growth Restriction: A Systematic Review of Literature

Intrauterine growth restriction (IUGR) affects nearly 10 to 15% of pregnancies and is responsible for many short- and long-term adverse consequences, including hemostatic derangement. Both thrombotic and hemorrhagic events are described in the perinatal period in these neonates. The aim of this study was to systematically review the literature on the laboratory studies used to evaluate the hemostatic system of the IUGR small for gestational age neonate. We reviewed the current literature via PubMed and Scopus until September 2022. Following our inclusion/exclusion criteria, we finally included 60 studies in our review. Thrombocytopenia, characterized as hyporegenerative and a kinetic upshot of reduced platelet production due to in utero chronic hypoxia, was the main finding of most studies focusing on growth-restricted neonates, in most cases is mild and usually resolves spontaneously with the first 2 weeks of life. In regard to coagulation, growth-restricted newborns present with prolonged standard coagulation tests. Data regarding coagulation factors, fibrinolytic system, and anticoagulant proteins are scarce and conflicting, mainly due to confounding factors. As thromboelastography/rotational thromboelastometry (TEG/ROTEM) provides a more precise evaluation of the in vivo coagulation process compared with standard coagulation tests, its use in transfusion guidance is fundamental. Only one study regarding TEG/ROTEM was retrieved from this population, where no difference in ROTEM parameters compared with appropriate for gestational age neonates was found. Despite the laboratory aberrations, no correlation could be achieved with clinical manifestations of bleeding or thrombosis in the studies included. More studies are needed to assess hemostasis in IUGR neonates and guide targeted therapeutic interventions.

Neonatal Platelet Transfusions: Starting Again

Preterm neonates with severe thrombocytopenia are frequently prescribed prophylactic platelet transfusions despite no evidence of benefit. Neonatal platelet transfusion practice varies, both nationally and internationally. Volumes and rates of transfusion in neonatology are based on historic precedent and lack an evidence base. The etiology of harm from platelet transfusions is poorly understood. Neonates are expected to be the longest surviving recipients of blood produce transfusions, and so avoiding transfusion associated harm is critical in this cohort. This article reviews the evidence for and against platelet transfusion in the neonate and identifies areas of future potential neonatal platelet transfusion research.

The relationship between platelet indices and patent ductus arteriosus in preterm infants: a systematic review and meta-analysis

Patent ductus arteriosus (PDA), one of the most common disorders in newborns, is associated with many complications in premature infants such as respiratory distress syndrome (RDS) and bronchopulmonary dysplasia (BPD). However, the diagnosis of hemodynamically significant patent ductus arteriosus (hsPDA) is still an ongoing debate. The relationship between platelet parameters and hsPDA has been explored in many studies over the last decade, but there is still no definite conclusion. We aim to explain the relationship between platelet parameters and hsPDA through this meta-analysis. Therefore, we used PubMed, Embase, the Cochrane Library, and Web of Science databases as well as the Google Scholar to search for studies up to May 2020. Three reviewers independently screened the articles, evaluated the quality of the articles, and collected the data. The random-effects model and fixed-effects model were used to evaluate pooled results. We used the I-square (I²) test to examine heterogeneity and the funnel plot; Egger's test and meta-regression analysis were used to test for publication bias. Influence analysis was also carried out in this study. Stata version 12.0 software was used for data analysis. Fourteen studies, which included 3330 newborns, were extracted from 986 studies. The weighted mean difference (WMD) of the platelet count was - 17.98 (p < 0.001), the platelet distribution width (PDW) was 0.27 (p = 0.266), the mean platelet volume (MPV) was 0.01 (p = 0.958), the plateletcrit (PCT) was - 0.03 (p < 0.001), and the platelet mass was - 150.10 (p = 0.001).Conclusion: Platelet count, PCT, and platelet mass of the first 3 days of life are potentially helpful in identifying premature infants at risk of hsPDA. More prospective studies on the relationship between different degrees of thrombocytopenia and platelet function and hsPDA should be conducted. What is Known: • Platelets are involved in the formation of thrombi during closure of the arterial duct. • The diagnosis of hsPDA by Doppler echocardiography and clinical signs is not precise enough. What is New: • Preterm newborns with hsPDA in the first week of life demonstrated a significant reduction in platelet count, platelet mass, and plateletcrit in the first 3 days of life. • No significant difference was shown between hsPDA and non-hsPDA infants in platelet distribution width and mean platelet volume in the first 3 days of life.

Thrombocytopenia in Neonates

Thrombocytopenia defined as platelet count below 150,000/μL is not an uncommon event at the neonatal intensive care unit (NICU). In our region we calculated a prevalence of nearly 2 of 1000 live births. Early-onset neonatal thrombocytopenia (NT) occurring within the first 72 hours of life is more common than late-onset NT. Preterm infants are affected more often than term infants and bacterial infection is the most common diagnosis associated with NT. There are a lot of maternal, perinatal, and neonatal causes associated with NT and complications include bleedings with potentially life-threatening intracranial hemorrhage. Alloimmune thrombocytopenia (NAIT) often presents with severe thrombocytopenia (<30,000/μL) in otherwise healthy newborns and needs careful evaluation regarding HPA-1a antigen status and HLA typing. Platelet transfusions are needed in severe NT and threshold platelet counts might be at ≤25,000/μL irrespective of bleeding or not. Immune mediated NT recovers within 2 weeks with a good prognosis when there happened no intracranial hemorrhage. This short review gives an overview on etiology and causes of NT and recommendations regarding platelet transfusions.

Fetal Intraventricular Hemorrhage Due to Antiphospholipid Syndrome: A Case Report

Obstetric Antiphospholipid Syndrome (OAPS) is an autoimmune disease characterized by certain pregnancy complications in association with persistent antiphospholipid antibodies. These antibodies are generally known for their prothrombotic characteristics and may affect mother and fetus during the entire pregnancy. The clinical criteria for OAPS, including recurrent fetal loss, intra-uterine growth restriction and premature birth due to severe preeclampsia, all suggest uteroplacental vascular insufficiency. Although rare, thrombotic complications have been described in neonates born to mothers with OAPS, mainly ischemic stroke. We report on the first case of extensive fetal intraventricular hemorrhage related to OAPS. We share our diagnostic search and analysis for this unusual antenatal event, including cranial ultrasound findings and postmortem MRI images. We will also present a short review of the etiology and prognosis of antenatal intraventricular hemorrhage. We suggest that women with severe or early preeclampsia and/or a history of pregnancy loss should be evaluated for OAPS and carefully monitored throughout pregnancy. Further, we advise to test mothers for OAPS in the case of idiopathic fetal hemorrhage.

Neonatal thrombocytopenia-causes and outcomes following platelet transfusions

We evaluated the causes for neonatal thrombocytopenia (NT), the duration of NT, and the indications of platelet transfusions (PT) by means of a retrospective cohort study over a 23-year period. Neonates with NT were identified via ICD-10 code D69.6. Of 371 neonates (1.8/1000 live births) with NT, the majority (312; 84.1%) had early onset thrombocytopenia, and 282 (76%) were preterm born. The most frequent causes for NT were early and late onset sepsis and asphyxia. The mean duration of thrombocytopenia was 10.2 days and was negatively correlated (KK = - 0.35) with the number of PT. PT were given to 78 (21%) neonates, 38 (49%) of whom had very severe NT. The duration of NT was positively related to the severity of NT and the number of subsequent PT. A mortality rate of 10.8% was significantly associated with bleeding signs (p < 0.05) and correlated with increasing number of PT (p < 0.05) but not with the severity of NT (p = 0.4). In the case of relevant hemorrhage, PT did not influence the mortality rate (p = 0.09). All deaths followed neonatal sepsis.

CONCLUSIONS

Prematurity and diagnoses including early and late onset sepsis and asphyxia were the most common causes of NT. Mortality was not associated with the severity of NT but increased with the number of PT. What is Known: • The causes for neonatal thrombocytopenia (NT) are well known. • The effects of platelet transfusions (PT) and its indications are still a matter of debate and recommendations differ widely. What is New: • The duration of NT is positively related to the severity of NT and the number of subsequent PT. • The mortality rate is not associated with the severity of NT but increases with increasing numbers of PT and in the case of relevant intraventricular hemorrhage (≥ grade II), PT does not influence the mortality rate.

Platelet Counts and Patent Ductus Arteriosus in Preterm Infants: A Systematic Review and Meta-Analysis

BACKGROUND

Several cohort studies have shown an association between low platelet counts in the first day(s) of life and patent ductus arteriosus (PDA) in preterm infants. However, these results have not been confirmed by other studies.

OBJECTIVE

To perform a meta-analysis of all the studies addressing the relationship between platelet counts in the first day(s) of life and PDA in preterm infants.

METHODS

PubMed/MEDLINE and EMBASE were searched from their inception until December 2014. Results from 11 cohort studies involving 3,479 preterm infants (gestational age <32 weeks) were pooled using random-effects modeling.

RESULTS

Meta-analysis showed a significant positive association between PDA and platelet counts <150 × 10(9)/l [6 studies, risk ratio (RR) = 1.215, 95% CI: 1.027-1.436], between PDA and platelet counts <100 × 10(9)/l (5 studies, RR = 1.255, 95% CI: 1.034-1.525), and between significant PDA (SPDA) and platelet counts <100 × 10(9)/l (5 studies, RR = 1.254, 95% CI: 1.021-1.540). The association between SPDA and platelet counts <150 × 10(9)/l was not statistically significant (6 studies, RR = 1.289, 95% CI: 0.925-1.795). Pooled standard differences in mean platelet counts between infants with and without PDA/SPDA were not statistically different.

CONCLUSION

This meta-analysis reveals a marginal but significant association between low platelet counts in the first day(s) of life and PDA/SPDA in very preterm infants. This association needs to be confirmed in prospective studies.

Platelet counts in the first seven days of life and patent ductus arteriosus in preterm very low-birth-weight infants

BACKGROUND

Decreased platelet number and/or function are related to patent ductus arteriosus (PDA) in mice. Whether this is also the case in human infants remains controversial.

OBJECTIVES

To investigate the association between platelet count nadir within the first 7 days of life and the rate of hemodynamically significant PDA (HSPDA), as well as the rate of response to the treatment with cyclooxygenase (COX) inhibitors.

METHODS

This is a retrospective study of a cohort of 194 very low-birth-weight (VLBW) infants (<1,500 g) with gestational age <30 weeks. HSPDA was assessed by echocardiography on day 3 of life.

RESULTS

HSPDA was present in 105 infants (54.1%). Of these, 101 were treated with COX inhibitors. The treatment failure rate was 21.8%. Median platelet count nadir and rate of thrombocytopenia - defined as platelet count <150 × 10(9)/l and graded as mild (100 to <150 × 10(9)/l), moderate (50 to <100 × 10(9)/l) or severe (<50 × 10(9)/l) - within the first 2 days of life were not significantly associated with the presence of HSPDA on day 3. Moreover, low platelet counts, either on days 1-2 or 3-7, were not significantly associated with the rate of response to treatment with COX inhibitors.

CONCLUSIONS

Our data provide further evidence for the lack of association between platelet counts within the first days of life and either spontaneous or pharmacological closure of the ductus arteriosus in VLBW infants.

Hypoxia as a predisposing factor for the development of early onset neonatal thrombocytopenia

Background:

Thrombocytopenia in hypoxic neonates admitted in NICU is a morbid condition encountered very commonly. Early-onset thrombocytopenia (<72 h) is most commonly associated with fetomaternal conditions complicated by placental insufficiency and/or fetal hypoxia. Chronic intrauterine hypoxia is the most frequent cause of early-onset thrombocytopenia in preterm neonates.

Aims:

In this study incidence and clinical impact of early thrombocytopenia in hypoxic neonates was investigated.

Setting and Design:

Neonatal intensive care unit of a tertiary level hospital attached to a medical college in Central India. A cross-sectional, observational hospital based study in hypoxic neonates for development of thrombocytopenia.

Materials and Methods:

603 hypoxic newborns were evaluated for development of thrombocytopenia. 155 (25.07%) developed thrombocytopenia and were the cases. Non thrombocytopenic babies 448 (74.29%) served as controls. The two groups were compared for birth weight, sex ratio, gestational age, severity of asphyxia, platelet counts and mortality rate.

Statistical Analysis:

Descriptive statistics of continuous variable were expressed in mean and SD. P value less than or equal to 0.05 were statistically significant.

Results and Conclusions:

We found thrombocytopenia to be associated with male gender, prematurity and low birth weight. Most babies had mild to moderate thrombocytopenia. Mortality was higher in preterm thrombocytopenic babies as compared to term. We suggest screening for thrombocytopenia in all asphyxiated newborns, as hypoxia can lead to neonatal thrombocytopenia.

Low immature platelet fraction suggests decreased megakaryopoiesis in neonates with sepsis or necrotizing enterocolitis

OBJECTIVE

In order to conclude on the megakaryopoietic activity during thrombocytopenia in sepsis or necrotizing enterocolitis (NEC), we analyzed the immature platelet fraction (IPF).

STUDY DESIGN

Serial measurements of platelet counts and IPF in neonates with blood culture-proven late-onset sepsis (n=21) or surgical NEC (n=12) at T0: prior to the diagnosis of sepsis/NEC; T1: at diagnosis; T2: days 3 to 5 after onset; T3: days 8 to 12 after onset.

RESULT

In parallel to declining platelet counts, the median absolute IPF significantly decreased between T0 and T2 in neonates with sepsis or NEC. We found a significant positive correlation between the platelet count and absolute IPF (r=0.71; P<0.001). In patients with low IPF (<2 per nl), the platelet count did not subsequently increase. Neonates with NEC who died exhibited significantly lower IPF compared with survivors (P<0.05).

CONCLUSION

Low absolute IPF values during the course of neonatal sepsis/NEC suggest suppression of megakaryopoietic activity.

The prevalence and outcomes of thrombocytopenia in a neonatal intensive care unit: a three-year report

Neonatal thrombocytopenia is one of the most common hematologic disorders in neonatal intensive care units (NICUs). The purpose of this study was to determine the prevalence of thrombocytopenia and whether thrombocytopenia has an effect on the occurrence of intraventricular hemorrhage (IVH) ≥ grade 2 and on mortality rate. This study was carried out retrospectively in neonates admitted to NICU of Cumhuriyet University in Sivas, Turkey, between 2009 and 2012. Among 2218 neonates evaluated, 208 (9.4%) developed thrombocytopenia. The prevalence of IVH ≥ grade 2 was more in infants with thrombocytopenia (7.2%) than in those without thrombocytopenia (4.4%), although this was not statistically significant (P = .08). In univariate analysis, IVH ≥ grade 2 was higher in cases with very severe thrombocytopenia (35.7%, n = 5) than in those with mild (2.1%, n = 2), moderate (4.7%, n = 3), and severe thrombocytopenia (15.2%, n = 5) (P = .04). Multivariate logistic regression analysis showed that birth weight <1500 g (OR 6.2, 95% CI 3.4-9.8; P = .0001), gram-negative sepsis (OR 2.5, 95% CI 1.8-4.2; P = .01), very severe thrombocytopenia (OR 1.3, 95% CI 1.1-2.1; P = .03), and platelet transfusion ≥2 (OR 7.3, 95% CI 4.1-12.1; P = .001) were significant risk factors for mortality. The results of our study suggest that outcomes of neonates with thrombocytopenia depend not only on platelet count but also on decreased gestational age or birth weight, prenatal factors, and sepsis.

Congenital amegakaryocytic thrombocytopenia: a brief review of the literature

Congenital amegakaryocytic thrombocytopenia (CAMT) is a rare inherited autosomal recessive disorder that presents with thrombocytopenia and absence of megakaryocytes. It presents with bleeding recognized on day 1 of life or at least within the first month. The cause for this disorder appears to be a mutation in the gene for the thrombopoeitin (TPO) receptor, c-Mpl, despite high levels of serum TPO. Patients with severe Type I-CAMT carry nonsense Mpl mutations which causes a complete loss of the TPO receptor whereas those with Type II CAMT carry missense mutations in the Mpl gene affecting the extracellular domain of the TPO receptor. Differential diagnosis for severe CAMT includes thrombocytopenia with absent radii (TAR) and Wiskott-Aldrich syndrome (WAS). The primary treatment for CAMT is bone marrow transplantation. Bone Marrow/Stem Cell Transplant (HSCT) is the only thing that ultimately cures this genetic disease. Newer modalities are on the way, such as TPO-mimetics for binding towards partially functioning c-Mpl receptors and gene therapy. Prognosis of CAMT patients is poor, because all develop in childhood a tri-linear marrow aplasia that is always fatal when untreated. Thirty percent of patients with CAMT die due to bleeding complications and 20% -due to HSCT if it has been done.

New insights into the mechanisms of nonimmune thrombocytopenia in neonates

Thrombocytopenia affects up to 35% of all patients admitted to the neonatal intensive care unit. The causes of thrombocytopenia in neonates are very diverse and include immune and nonimmune disorders. Most cases of thrombocytopenia encountered in the neonatal intensive care unit are nonimmune, and these will constitute the focus of this review. Specifically, we first discuss the biological differences between neonatal and adult megakaryocytopoiesis, which contribute to explain the vulnerability of neonates to develop thrombocytopenia. Next, we review new diagnostic tools that have allowed for a better evaluation of platelet production in neonates, without having to obtain a bone marrow sample. Finally, we summarize our current understanding of the mechanisms underlying the thrombocytopenia in several common neonatal conditions, such as chronic intrauterine hypoxia, sepsis and necrotizing enterocolitis, and viral infections. A better understanding of the mechanisms underlying these varieties of thrombocytopenia is critical to develop disease-specific treatment protocols and to begin to entertain the possibility of using novel thrombopoietic growth factors to treat selected neonates with severe thrombocytopenia.

Platelet transfusion practices among neonatologists in the United States and Canada: results of a survey

OBJECTIVE

In the absence of scientific evidence, current neonatal platelet transfusion practices are based on physicians' preferences, expert advice, or consensus-driven recommendations. We hypothesized that there would be significant diversity in platelet transfusion triggers, product selection, and dosing among neonatologists in the United States and Canada.

METHODS

A Web-based survey on neonatal platelet transfusion practices was distributed to all members of the American Academy of Pediatrics Perinatal Section in the United States and to all physicians listed in the 2005 Canadian Neonatology Directory.

RESULTS

The overall response rate was 37% (1060 of 2875). In the United States, 37% (1007 of 2700) responded, of which 52% practiced at academic centers. Thirty percent (53 of 175) of Canadians responded, of whom 94% practiced at academic centers. As hypothesized, there was significant practice diversity in both countries. The survey also revealed that platelet transfusions are frequently administered to nonbleeding neonates with platelet counts of >50 x 10(9)/L. This practice is particularly prevalent among neonates with specific clinical conditions, including indomethacin treatment, preceding procedures, in the postoperative period, or with intraventricular hemorrhages.

CONCLUSIONS

There is great variability in platelet transfusion practices among US and Canadian neonatologists, suggesting clinical equipoise in many clinical scenarios. Prospective randomized clinical trials to generate evidence-based neonatal platelet transfusion guidelines are needed.

Intracranial hemorrhage in term newborns: management and outcomes

Child neurology is frequently a late player in the management of the term newborn with intracranial hemorrhage in the first neonatal week. It is crucial, however, that the child neurologist undertake a comprehensive evaluation by investigating etiology and management of the hemorrhage. Intracranial hemorrhage is usually associated with premature newborns. The literature on intracranial hemorrhage in term newborns is largely in the form of isolated case reports or a small series of cases, and mostly nonsystematic. Presented here is an evidence-based review of the incidence, risk factors, etiologies, and clinical management of intracranial hemorrhage in the first week after birth, with discussion of the role of neuroimaging and hematologic investigation. Consideration of these investigations along with documentation of every intervention or its explanation will reduce parental anxiety and will assure the best possible neurologic as well as legal outcomes of term newborns with intracranial hemorrhage.

Neonatal thrombocytopenia associated with maternal pregnancy induced hypertension

OBJECTIVE

To evaluate the prevalence of thrombocytopenia in neonates born to mothers with pregnancy induced hypertension (PIH) and identify the associated material and neonatal characteristics.

METHODS

In the current, prospective study, platelet counts were assessed serially. Maternal and neonatal characteristic were recorded in pre-designed proforma. Primary outcome measures were thrombocytopenia defined as platelet count of <150,000/mm(3) and severe thrombocytopenia if counts were <30,000/mm(3) or <50,000/mm(3) with bleeding.

RESULTS

Of 97 neonates born to PIH mothers 35 (36.1%) had thrombocytopenia. In 20 (20.6%) thrombocytopenia was severe. Higher percentage of thrombocytopenia was associated with male gender (47.7%), low birth weight (71.4%) and prematurity (67.4%). Severe thrombocytopenia was significantly associated with low birth weight (OR: 4.58; 95% CI: 0.98-21.3; p<0.03) and prematurity (OR: 2.52; 95% CI: 0.87-7.24; p<0.05). Material parity, onset of PIH, and medications did not seem to be associated significantly.

CONCLUSION

Premature and low birth weight neonates born to mothers with pregnancy induced hypertension would require scrutiny for thrombocytopenia during early neonatal period.

Transfusion therapy in critically ill children

Critically ill children in pediatric intensive care units are commonly indicated for blood transfusion due to many reasons. Children are quite different from adults during growth and development, and that should be taken into consideration. It is very difficult to establish a universal transfusion guideline for critically ill children, especially preterm neonates. Treating underlying disease and targeted replacement therapy are the most effective approaches. Red blood cells are the first choice for replacement therapy in decompensated anemic patients. The critical hemoglobin concentration may be higher in critically ill children for many reasons. Whole blood is used only in the following conditions or diseases: (1) exchange transfusion; (2) after cardiopulmonary bypass; (3) extracorporeal membrane oxygenation; (4) massive transfusion, especially in multiple component deficiency. The characteristics of hemorrhagic diseases are so varied that their therapy should depend on the specific needs associated with the underlying disease. In general, platelet transfusion is not needed when a patient has platelet count greater than 10,000/mm3 and is without active bleeding, platelet functional deficiency or other risk factors such as sepsis. Patients with risk factors or age less than 4 months should be taken into special consideration, and the critical thrombocyte level will be raised. Platelet transfusion is not recommended in patients with immune-mediated thrombocytopenia or thrombocytopenia due to acceleration of platelet destruction without active bleeding or life-threatening hemorrhage. There are many kinds of plasma-derived products, and recombinant factors are commonly used for hemorrhagic patients due to coagulation factor deficiency depending on the characteristics of the diseases. The most effective way to correct disseminated intravascular coagulation (DIC) is to treat the underlying disease. Anticoagulant therapy is very important; heparin is the most common agent used for DIC but the results are usually not satisfactory. Antithrombin III, protein C, or recombinant thrombomodulin has been used successfully to treat this condition. For reducing the risk of organism transmission and adverse reactions resulting from blood transfusion, the following measures have been suggested: (1) replacement therapy using products other than blood (e.g., erythropoietin, iron preparation, granulocyte colony-stimulating factor); (2) special component replacement therapy for specific diseases; (3) autotransfusion; (4) subdividing whole packed blood products into smaller volumes to reduce donor exposure; (5) advances in virus-inactivating procedures. To avoid viral transmission, vapor-heated or pasteurized products and genetic recombinant products are recommended. Cytomegalovirus (CMV)-seronegative blood, leukoreduced and/or irradiated blood are recommended for prevention of CMV infection, graft-versus-host-disease and alloimmunization in neonate and immunocompromised patient transfusion. There is no reason to prescribe a plasma product for nutritional supplementation because of the risk of complications. The principle: complications of transfusion must be avoided, the rate of blood exposure should be reduced and the safety of the transfused agents or components should be maintained must always be kept in mind.

Advances and controversies in neonatal ICU platelet transfusion practice

Some of the platelet transfusions currently given to NICU patients are unnecessary and convey no benefits. Although ordered with good intentions, unnecessary platelet transfusions carry known and unknown risks. Identifying and eliminating any unnecessary platelet transfusions in NICUs would be a step toward better care, lower costs, and more careful preservation of blood component resources. A renewed interest in platelet transfusion studies is needed, if essential data is to be gathered to improve NICU platelet transfusion practice. Retrospective studies can be of value: for instance, seeking associations between bleeding events and platelet counts can suggest the possibility of cause and effect relationships. Such studies might identify approximate platelet count levels that convey high hemorrhagic risk and might help focus future prospective trials. Prospective indirect studies also can be of value, for instance, measuring the template bleeding time and the PFA-100 closure time as a function of platelet count and perhaps as a function of circulating platelet mass, and would provide new information with relevance to platelet transfusion benefits. Such studies might give a better awareness of how low the platelet count can fall before platelet plug formation is impaired. It seems inescapable, however, that new, multicentered, randomized, prospective studies are needed, where NICU patients are assigned different platelet transfusion triggers and then carefully tracked for bleeding events and long-term neurodevelopmental outcomes. Only that type of study is likely to generate the evidence base needed for widespread implementation of improvements in NICU platelet transfusion practice.

Do platelet transfusions in the NICU adversely affect survival? Analysis of 1600 thrombocytopenic neonates in a multihospital healthcare system

OBJECTIVE

Several studies have indicated a correlation between the number of platelet transfusions received by newborn intensive care unit (NICU) patients and the mortality rate. The number of platelet transfusions might be a marker for level of illness, and thus predictive of mortality. However, an alternative hypothesis is that multiple platelet transfusions themselves are harmful in this population.

STUDY DESIGN

We evaluated data from all thrombocytopenic neonates cared for in the Intermountain Healthcare NICUs in the past 4 years, seeking associations between the lowest platelet count recorded, number of platelet transfusions received and mortality rate. We also conducted a sensitivity analysis to examine the hypothesis that platelet transfusions were responsible for some fraction of the mortality rate.

RESULT

Transfusion and outcome data were examined from 1600 thrombocytopenic NICU patients. At any level of platelet count, some patients received platelet transfusions but others did not. However, at all levels of platelet count, those that received platelet transfusions had a higher mortality rate. Neonates not given any platelet transfusions had a mortality rate of 2%, those with 1 or 2 transfusions had a mortality rate of 11% (P<0.001); those with >10 had a mortality rate of 35% (P<0.001); and those with > or = 20 had a mortality rate of 50% (P<0.001). A sensitivity analysis suggested that the platelet transfusions themselves were very likely responsible for some fraction of the increasing mortality rate.

CONCLUSION

The number of platelet transfusions administered in the NICU predicts the mortality rate. Some of this correlation is ascribable to unknown and unmeasured factors such as level of illness. However, the present data and the sensitivity analysis both suggest that some of this correlation is due to harmful effects of multiple platelet transfusions in this group of patients.

Thrombocytopenia related neonatal outcome in preterms

OBJECTIVE

To investigate the thrombocytopenia and platelet transfusion related outcome in very preterm infants.

METHODS

Cases (n=94) with at least one episode of thrombocytopenia (platelet counts < 150 x 10(9)/L) and controls (n=70) were identified from a database of 1054 neonates with gestational age < or = 32 weeks admitted to a level III NICU. Thrombocytopenia and platelet transfusion related morbidity (IVH, sepsis, NEC, and bleeding) and mortality were analyzed with respect to gestational age (< 28 weeks and 28-32 weeks), severity of thrombocytopenia (mild if platelet count > or = 100 and < 150 x 10(9)/L, moderate if count > or = 50 and < 100 x 10(9)/L, and severe if platelets < 50 x 10(9)/L), age of thrombocytopenia onset (early < 72 hours and late > or =72 hours).

RESULTS

The majority of thrombocytopenia (67.0%) was diagnosed after 72 hours of age, and was mild in 12.8%, moderate in 36.2% and severe in 51.0% of the cases. Neonates with severe and moderate thrombocytopenia were more frequently born at lower gestational age and birth weight. NEC and sepsis especially that caused by Candida infection, were associated with severe thrombocytopenic events. The development of IVH was strongly associated with lower gestational age but not the severity and age of thrombocytopenia onset. Mucocutaneous bleeding complicated 18.4% of cases with severe and late-onset thrombocytopenia (7/38). Platelets were transfused to 85.4% of infants with severe and 64.7% of infants with moderate thrombocytopenia (P< 0.02). The gestational age of the majority of the platelet transfused neonates (49/60, 81.7%) was < 28 weeks. Mean gestational age and birth weight, and rates of severe thrombocytopenia, IVH, sepsis and mortality were comparable in transfused vs not-transfused infants with gestational age 28-32 weeks. Platelet transfused neonates with gestational age < 28 weeks had lower birth weights, were more often severely thrombocytopenic, and died more frequently than infants of a similar gestational age who were not transfused.

CONCLUSION

Platelet transfusions did not lower mortality in very premature born infants with moderate and severe thrombocytopenia during the NICU admission.

Platelet transfusions in infants with necrotizing enterocolitis do not lower mortality but may increase morbidity

OBJECTIVE

Necrotizing enterocolitis (NEC), a serious multisystemic inflammatory disease most commonly seen in premature neonates, is often associated with thrombocytopenia. Infants with severe forms of NEC commonly have platelet counts of less than 50,000/mm(3), occasionally less than 10,000/mm(3). Despite an absence of data to support the practice, platelet transfusions are commonly used to maintain a certain arbitrary platelet count in an effort to prevent bleeding. As platelet transfusions contain a variety of bioactive factors including pro-inflammatory cytokines, we hypothesized that a higher number and volume of platelet transfusions would not be associated with an improvement in mortality or morbidity.

STUDY DESIGN

A retrospective cohort analysis was conducted of the medical records of all infants between 1997 and 2001 with Bell's Stage 2 or 3 NEC associated with platelet counts of <100,000/mm(3). The medical records were evaluated for the following variables: platelet counts, number and volume of platelet transfusions, symptoms of bleeding, and hospital course. Mortality and development of short bowel syndrome and/or cholestasis were correlated to the total number and volume (total ml and ml/kg) of platelet transfusions. Differences between the outcome groups were compared using the independent t-test, Fisher's exact test and Mann-Whitney tests.

RESULTS

A total of 46 infants met the study criteria (gestational age 28+/-4 weeks and birth weight 1166+/-756 g, mean+/-SD). There were a total of 406 platelet transfusions administered to the study population. Of these, 151 (37.2%) were given in the presence of active bleeding, with 62% of these resulting in the cessation of bleeding within 24 hours. Other listed indications for platelet transfusions were hypovolemia and severe thrombocytopenia. On analysis of the entire cohort, there was no statistical improvement in either mortality or morbidity (short bowel syndrome and cholestasis) with greater number and/or volume of platelet transfusions. Furthermore, we found that infants who developed short bowel syndrome and/or cholestasis had been given a significantly higher number and volume of platelet transfusions when compared to those who did not have these adverse outcomes [median (minimum - maximum) - number of transfusions : 9 (0 to 33) vs 1.5 (0 to 20), p=0.010; volume of transfusions (ml/kg): 121.5 (0 to 476.6) vs 33.2 (0 to 224.3), p=0.013].

CONCLUSION

This retrospective analysis suggests that greater number and volume of platelet transfusions in infants with necrotizing enterocolitis are associated with greater morbidity in the form of short bowel syndrome and/or cholestasis without the benefit of lower mortality.

Patterns of thrombocytosis and thrombocytopenia in hospitalized neonates

OBJECTIVE

We sought to identify changes in platelet (PLT) counts over time, and to evaluate the patterns of thrombocytopenia and thrombocytosis in hospitalized infants 23.8 weeks to term gestation.

STUDY DESIGN

Neonates were divided into four gestational age groups and their PLT counts were retrospectively compared for prevalence of thrombocytopenia, thrombocytosis, and associated conditions.

RESULTS

Postconceptional age, postnatal age, and sepsis (among other factors) affected PLT counts. When counts from noninfected appropriately grown infants were evaluated, the risk of thrombocytopenia and thrombocytosis were highest in the most preterm infants, and these risks changed with corrected gestational age. PLT counts increased weekly over the first 4 weeks of life for all but the most preterm infants.

CONCLUSIONS

These data characterize the incidence of thrombocytopenia and thrombocytosis across a wide range of gestational ages and show that, even in noninfected neonates, these conditions are common, and risk decreases with increasing maturity. The age-related changes in PLT patterns may reflect maturation of platelet regulation.

Cloning and expression of the first nonmammalian interleukin-11 gene in rainbow trout Oncorhynchus mykiss

Interleukin (IL)-11 is a multifunctional cytokine that stimulates hematopoietic progenitor cells and exerts a series of important immunomodulatory effects. It was believed to be restricted to mammals, but here we report the first nonmammalian IL-11 gene, in rainbow trout (Oncorhynchus mykiss). A trout IL-11 cDNA clone was isolated that contains a 5'-untranslated region (UTR) of 400 bp, an open reading frame of 612 bp and a large 3'-UTR of 1924 bp. Analysis of a genomic DNA clone from a trout lambda library revealed that the trout IL-11 gene has the same five exon/four intron gene organization, as well as the same intron phase, as mammalian IL-11 genes. The 204 amino acid trout IL-11 translation has a predicted signal peptide of 26 amino acids and mature peptide of 178 amino acids, with a calculated molecular mass of 20.5 kDa and a theoretical pI of 9.83. The mature peptide contains a cysteine residue and a potential N-linked glycosylation site that are not present in mammals. Phylogenetic analysis clearly grouped trout IL-11 with IL-11 molecules from other species and separated from other members of the IL-6 family. The IL-11 gene is highly expressed in intestine and gills in healthy fish and its expression can also be detected in spleen, head kidney, brain, skin and muscle. Bacterial infection of rainbow trout markedly up-regulates IL-11 expression in liver, head kidney and spleen. IL-11 expression is also up-regulated in RTS-11 cells (a trout macrophage cell line), which constitutively expressed the lowest level of IL-11 of the four trout cell lines examined, after stimulation with bacteria, lipopolysaccharide, poly(I:C) and recombinant trout IL-1beta. Only a single transcript of 3.2 kb could be detected in lipopolysaccharide or recombinant IL-1beta-stimulated RNA samples by northern blotting. The expression results, showing that IL-11 is widely distributed and modulated by infection and other cytokines, suggest that fish IL-11 is an active player in the cytokine network and the host immune response to infection.

Evaluation and treatment of severe and prolonged thrombocytopenia in neonates

Thrombocytopenia is one of the most common hematologic problems in the neonatal intensive care unit (NICU). Despite its prevalence,several basic pathophysiologic questions remain unanswered. For instance, there is a lack of evidence-based guidelines for treatment,and the kinetic mechanisms (decreased platelet production,increased platelet consumption, or sequestration) responsible for most varieties of neonatal thrombocytopenia are not well defined.Moreover, a clear correlation between degree of thrombocytopenia and the resulting bleeding risk has not been demonstrated, and no transfusion-trigger studies have been conducted in neonates. As a consequence of these deficiencies in knowledge, there is great variability in platelet transfusion practices among NICUs. This article presents an overview of the evaluation of a neonate with severe thrombocytopenia and a review of current and projected therapeutic options.