Newborn face mask ventilation training using a standardised intervention and respiratory function monitor: a before and after manikin study.

OBJECTIVE: The International Liaison Committee on Resuscitation has recommended improvements in training for neonatal resuscitation, highlighting the potential role of respiratory function monitors (RFMs). Our objective was to determine whether a manikin-based, standardised face mask ventilation training intervention using an RFM with a simple visual display reduced face mask leak. DESIGN: Multicentre, before and after study. Participants and instructors were blinded to the RFM display during both assessment periods. PARTICIPANTS: Healthcare professionals working or training in a hospital providing maternity and neonatal services. INTERVENTION: All participants underwent a training intervention on positive pressure ventilation using a modified, leak-free manikin and RFM. The intervention consisted of a demonstration of optimal face mask ventilation technique, training in RFM interpretation with corrective strategies for common scenarios and a period of deliberate practice. Each participant performed 30 s of positive pressure ventilation blinded to the RFM display before and after training. MAIN OUTCOME MEASURES: The primary outcome was face mask leak (%) measured after training. Secondary outcome measures included expired tidal volume, inflating pressures and ventilation rate. Adjustments made to technique during training were an important qualitative outcome. RESULTS: Four hundred and fourteen participants were recruited over a 13-month period from April 2022, and 412 underwent analysis. Median (IQR) face mask leak before training was 31% (10-69%) compared with 10% (6-18%) after training (p<0.0001). Improvements were noted across all other ventilation parameters. CONCLUSION: Standardised face mask ventilation training using an RFM with simple visual feedback led to a significant reduction in leak.

Markers of platelet activation foR identification of late onset sEpsis in infaNTs: PARENT study protocol.

BACKGROUND: Newborns are at high risk of sepsis. At present there is no definitive "rule in" blood test for sepsis at the point of clinical concern. A positive blood culture remains the gold standard test for neonatal sepsis, however laboratory markers that correlate prospectively with culture positive sepsis could aid clinicians in making decisions regarding administration of empiric antibiotic therapies. METHODS: This multi-site, prospective observational study will take place in two neonatal intensive care units (National Maternity Hospital and Rotunda Hospital, Dublin). Neonates born at less than 34 weeks will be enroled and informed consent obtained prior to late onset sepsis work up. If at any point subsequently during their neonatal intensive care stay they develop signs and symptoms of possible sepsis requiring blood culture, an additional sodium citrate sample will be obtained. Infants will be categorised into three groups as follows: (i) culture positive sepsis, (ii) culture negative sepsis where an infant receives 5 days of antibiotics (iii) non sepsis. Our primary outcome is to establish if differential platelet/endothelial activation can prospectively identify neonatal culture positive late onset sepsis. TRIAL REGISTRATION NUMBER: NCT05530330 IMPACT: Preterm infants are a high risk group for the development of sepsis which is a major cause of mortality in this population. Platelets have been associated with host response to invasive bacterial infections both in animal models and translational work. A positive blood culture is the gold standard test for neonatal sepsis but can be unreliable due to limited blood sampling in the very low birth weight population. This study hopes to establish if platelet/endothelial associated plasma proteins can prospectively identify late onset neonatal sepsis.

Management of neonatal hypoglycaemia in a tertiary maternity unit-A multidisciplinary quality improvement project.

AIM: Improved identification and treatment of infants at risk of hypoglycaemia using evidence-based guidelines. METHODS: Design: Prospective, multidisciplinary quality improvement project (QIP). SETTING: Tertiary maternity hospital, Dublin (2016-2023). SUBJECTS: Infants at risk for neonatal hypoglycaemia. INTERVENTION: Plan-Do-Study-Act methodology. A hospital-wide survey and ongoing audit informed our initiatives including staff education, antenatal maternal education and standardisation of equipment. Our guidelines were continually evaluated and updated based on emerging evidence. MAIN OUTCOME MEASURES: Neonatal unit (NNU) admissions, adherence to guidelines and use of glucose gel. RESULTS: NNU admissions decreased by 70%, from 3% (118/3883) to 0.9% (34/3806 infants). The number requiring an IV glucose bolus reduced from 25% (29/118) to 6% (2/34). Improved antenatal education, antenatal expression of colostrum and early and frequent feeding also contributed to a reduction in glucose gel use of 94% (1009 tubes in 2018-v-62 in 2022). There were no adverse side effects related to hypoglycaemia. CONCLUSION: Our QIP resulted in a significant reduction in NNU admissions leading to significant cost reductions and NNU workload. More importantly, this resulted in less maternal-infant separation and potentially less parental anxiety and a more supportive environment for breastfeeding. These low-cost initiatives can be implemented in other tertiary maternity hospitals to improve maternity and newborn care.

Parents' understanding and experiences of blood component transfusion in the neonatal intensive care unit: A qualitative study.

AIM: Blood component transfusion is a common intervention in the neonatal intensive care unit (NICU). Parents consent on their babies' behalf. This study aimed to explore parents' understandings and experiences of consenting and the subsequent blood transfusion. METHODS: A "low inference" qualitative descriptive semi-structured interview approach was utilised. Grounded theory was employed. Parents described their memories of babies' transfusions, their responses to the consent process and assessed the written information they were given. RESULTS: A purposive sample of 17 parents whose babies required blood transfusion in the NICU participated. Parents talked about their initial fears of transfusion, later replaced by confidence in the process and results of transfusion and trust in the healthcare professional team. The main themes elicited by the interviews were parents' expectations and outcomes of transfusion, parents' prior and current opinions of transfusion, parents trust in healthcare professionals and how parents would like to receive information about transfusions in the NICU. CONCLUSION: Parents in our study trust information from the healthcare professionals caring for their baby and would like more specific information about how blood transfusion will impact their baby, in a variety of means. Parents felt that blood transfusions were beneficial for their babies.

Changes in inflammatory proteins following platelet transfusion in a neonatal population.

BACKGROUND: Studies have demonstrated increased morbidity and mortality with platelet transfusions in the neonatal period. Platelets are as important for host immunity and inflammation as for hemostasis. Increased inflammation may explain the dose-associated increase in mortality, bleeding, and lung disease. OBJECTIVE: This study aims to assess if there are any changes in inflammatory cytokines post-platelet transfusion in babies in NICU. METHODS: This prospective observational study recruited babies due to receive a non-emergency platelet transfusion. Dried whole blood samples were collected prior to and 2 h post-transfusion. Samples were processed using multiplex immunoassay to enable analysis of tiny blood volumes. Statistical analysis was performed using R. RESULTS: Seventeen babies underwent 26 platelet transfusions across two centers. Median birthweight was 1545 g (535-3960 g) and median birth gestation was 31 weeks and 1 day (23 + 1 to 40 + 5). Median pre-transfusion platelet count was 19.5 × 109/l. There was a significant increase in levels of CXCL5 (p < 0.001), CD40 (p = 0.001), and TGF-ß (p = 0.001) in neonatal blood samples post-platelet transfusion in the study group. CONCLUSION: The increase in the cytokines CXCL5, CD40 and TGF-ß after platelet transfusion in babies in NICU could potentiate existing inflammation, NEC, lung, or white matter injury. This could potentially explain long-term harm from platelet transfusion in babies. IMPACT: There is a change in levels of immunomodulatory proteins CXCL5, CD40, and TGF-ß after platelet transfusion in babies in NICU. Murine neonatal models have demonstrated an increase in cytokine levels after platelet transfusions. This is the first time that this has been demonstrated in human neonates. The increase in proinflammatory cytokines could potentially explain the long-term harm from platelet transfusion in babies, as they could potentiate existing inflammation, NEC, lung injury, or white matter injury.

Safety and feasibility of platelet transfusion through long catheters in the neonatal intensive care unit: an in vitro study.

OBJECTIVE: To assess the safety and feasibility of platelet transfusion through small-bore long lines used in the neonatal intensive care unit (NICU), including double-lumen umbilical venous catheters (UVCs) and 24 G and 28 G peripherally inserted central catheters (PICCs). DESIGN: Prospective in vitro controlled study. SETTING: Blood transfusion service laboratory. METHODS: In vitro platelet transfusions were set up as per NICU practice. Transfusion line pressure was monitored. Post-transfusion swirling, presence of aggregates, pH analysis and automated cell count in vitro activation response by flow cytometry assessing CD62P expression were assessed. MAIN OUTCOME MEASURES: All transfusions completed successfully. The rate of infusion was reduced in 5 of 16 transfusions through 28 G lines due to 'pressure high' alarms. There was no difference in swirling values or transfusion aggregate formation, CD62P expression levels, platelet count, platelet distribution width, mean platelet volume, plateletcrit or platelet to large cell ratio across transfusions post-transfusion. CONCLUSIONS: This study showed that in vitro platelet transfusion performed through 24 G and 28 G neonatal PICC lines and double-lumen UVCs is non-inferior to 24 G short cannulas, using outcome measures of platelet clumping, platelet activation and line occlusion. This suggests that where available these lines can be used if necessary for platelet transfusion.

Cerebral Oximetry Monitoring in Extremely Preterm Infants.

BACKGROUND: The use of cerebral oximetry monitoring in the care of extremely preterm infants is increasing. However, evidence that its use improves clinical outcomes is lacking. METHODS: In this randomized, phase 3 trial conducted at 70 sites in 17 countries, we assigned extremely preterm infants (gestational age, <28 weeks), within 6 hours after birth, to receive treatment guided by cerebral oximetry monitoring for the first 72 hours after birth or to receive usual care. The primary outcome was a composite of death or severe brain injury on cerebral ultrasonography at 36 weeks' postmenstrual age. Serious adverse events that were assessed were death, severe brain injury, bronchopulmonary dysplasia, retinopathy of prematurity, necrotizing enterocolitis, and late-onset sepsis. RESULTS: A total of 1601 infants underwent randomization and 1579 (98.6%) were evaluated for the primary outcome. At 36 weeks' postmenstrual age, death or severe brain injury had occurred in 272 of 772 infants (35.2%) in the cerebral oximetry group, as compared with 274 of 807 infants (34.0%) in the usual-care group (relative risk with cerebral oximetry, 1.03; 95% confidence interval, 0.90 to 1.18; P = 0.64). The incidence of serious adverse events did not differ between the two groups. CONCLUSIONS: In extremely preterm infants, treatment guided by cerebral oximetry monitoring for the first 72 hours after birth was not associated with a lower incidence of death or severe brain injury at 36 weeks' postmenstrual age than usual care. (Funded by the Elsass Foundation and others; SafeBoosC-III ClinicalTrials.gov number, NCT03770741.).

Two-year outcomes following a randomised platelet transfusion trial in preterm infants.

OBJECTIVE: Assess mortality and neurodevelopmental outcomes at 2 years of corrected age in children who participated in the PlaNeT-2/MATISSE (Platelets for Neonatal Transfusion - 2/Management of Thrombocytopenia in Special Subgroup) study, which reported that a higher platelet transfusion threshold was associated with significantly increased mortality or major bleeding compared to a lower one. DESIGN: Randomised clinical trial, enrolling from June 2011 to August 2017. Follow-up was complete by January 2020. Caregivers were not blinded; however, outcome assessors were blinded to treatment group. SETTING: 43 level II/III/IV neonatal intensive care units (NICUs) across UK, Netherlands and Ireland. PATIENTS: 660 infants born at less than 34 weeks' gestation with platelet counts less than 50×109/L. INTERVENTIONS: Infants were randomised to undergo a platelet transfusion at platelet count thresholds of 50×109/L (higher threshold group) or 25×109/L (lower threshold group). MAIN OUTCOMES MEASURES: Our prespecified long-term follow-up outcome was a composite of death or neurodevelopmental impairment (developmental delay, cerebral palsy, seizure disorder, profound hearing or vision loss) at 2 years of corrected age. RESULTS: Follow-up data were available for 601 of 653 (92%) eligible participants. Of the 296 infants assigned to the higher threshold group, 147 (50%) died or survived with neurodevelopmental impairment, as compared with 120 (39%) of 305 infants assigned to the lower threshold group (OR 1.54, 95% CI 1.09 to 2.17, p=0.017). CONCLUSIONS: Infants randomised to a higher platelet transfusion threshold of 50×109/L compared with 25×109/L had a higher rate of death or significant neurodevelopmental impairment at a corrected age of 2 years. This further supports evidence of harm caused by high prophylactic platelet transfusion thresholds in preterm infants. TRIAL REGISTRATION NUMBER: ISRCTN87736839.

Nasal high-flow therapy to Optimise Stability during Intubation: the NOSI pilot trial.

OBJECTIVE: In adult patients with acute respiratory failure, nasal high-flow (NHF) therapy at the time of intubation can decrease the duration of hypoxia. The objective of this pilot study was to calculate duration of peripheral oxygen saturation below 75% during single and multiple intubation attempts in order to inform development of a larger definitive trial. DESIGN AND SETTING: This double-blinded randomised controlled pilot trial was conducted at a single, tertiary neonatal centre from October 2020 to October 2021. PARTICIPANTS: Infants undergoing oral intubation in neonatal intensive care were included. Infants with upper airway anomalies were excluded. INTERVENTIONS: Infants were randomly assigned (1:1) to have NHF 6 L/min, FiO2 1.0 or NHF 0 L/min (control) applied during intubation, stratified by gestational age (<34 weeks vs ≥34 weeks). MAIN OUTCOME MEASURES: The primary outcome was duration of hypoxaemia of <75% up to the time of successful intubation, RESULTS: 43 infants were enrolled (26 <34 weeks and 17 ≥34 weeks) with 50 intubation episodes. In infants <34 weeks' gestation, median duration of SpO2 of <75% was 29 s (0-126 s) vs 43 s (0-132 s) (p=0.78, intervention vs control). Median duration of SpO2 of <75% in babies ≥34 weeks' gestation was 0 (0-32 s) vs 0 (0-20 s) (p=0.9, intervention vs control). CONCLUSION: This pilot study showed that it is feasible to provide NHF during intubation attempts. No significant differences were noted in duration of oxygen saturation of <75% between groups; however, this trial was not powered to detect a difference. A larger, higher-powered blinded study is warranted.

Serial Assessment of Cardiac Function and Pulmonary Hemodynamics in Infants With Down Syndrome.

BACKGROUND: There is a dearth of longitudinal data describing the evolution of cardiopulmonary hemodynamics in infants with Down syndrome (DS) beyond infancy. We hypothesized that babies with DS, independent of the presence of congenital heart disease (CHD), demonstrate biventricular systolic and diastolic impairment and sustained elevation of pulmonary pressures compared with controls over the first 2 years of age. METHODS: This was a prospective observational cohort study of 70 infants with DS (48 with CHD and 22 without CHD) and 60 controls carried out in 3 tertiary neonatal intensive care units in Dublin, Ireland. Infants with DS with and without CHD and non-DS controls underwent serial echocardiograms at birth, 6 months, 1 year, and 2 years of age to assess biventricular systolic and diastolic function using deformation analysis. Pulmonary vascular resistance was assessed using pulmonary artery acceleration time and left ventricular (LV) eccentricity index. RESULTS: Infants with DS exhibited smaller LV (birth: 27 ± 4 vs 31 ± 2 mm, P < .01; 2 years: 43 ± 5 vs 48 ± 4 mm, P < .01) and right ventricular (birth: 28 ± 3 vs 31 ± 2 mm, P < .01; 2 years: 40 ± 4 vs 44 ± 3 mm, P < .01) lengths and lower LV (birth: -19% ± 3% vs -22% ± 2%, P < .01; 2 years: -24% ± 2% vs -26% ± 2%, P < .01) and right ventricular (birth: -19% ± 4% vs -22% ± 3%, P < .01; 2 years: -29% ± 6% vs -33% ± 4%, P < .01) systolic strain over the 2-year period. Pulmonary artery acceleration time was lower in the DS group throughout the study period (birth: 44 ± 10 vs 62 ± 14 ms, P < .01; 2 years 71 ± 12 vs 83 ± 11 ms, P < .01). No differences were observed between DS infants with and without CHD (all P > .05). CONCLUSIONS: Infants with DS exhibit impaired maturational changes in myocardial function and pulmonary vascular resistance. Such novel findings provide valuable insights into the pathophysiology affecting cardiorespiratory morbidity in this population.

Relationship Between Postnatal Pulmonary Arterial Pressure and Altered Diastolic Function in Neonates with Down Syndrome.

OBJECTIVE: To assess the influence of diastolic dysfunction on the evolution of pulmonary hypertension in neonates with Down Syndrome over the early newborn period. STUDY DESIGN: This was a prospective observational cohort study. Echocardiography was performed three times over the first week of life in both Down syndrome and control cohorts. Measurements of pulmonary arterial pressure in addition to left ventricular (LV) and right ventricular systolic and diastolic function were collected. RESULTS: Seventy babies with Down syndrome and 60 control infants were enrolled. Forty-eight of the infants with Down syndrome (69%) were born with congenital heart disease (CHD). Echocardiography surrogates of pulmonary hypertension and myocardial function remained significantly impaired in the Down syndrome group in comparison with control infants (all P < .01). In the Down syndrome group, LV early diastolic strain rate was independently associated with measures of pulmonary hypertension while controlling for gestational age, cesarean delivery, and the presence of CHD (P < .01). CONCLUSIONS: Intrinsic LV diastolic impairment is directly associated with higher indices of pulmonary hypertension in infants with Down syndrome and may be a contributing factor to its evolution.

Haematological issues in neonates with neonatal encephalopathy treated with hypothermia.

Neonatal encephalopathy (NE) is associated with abnormality of neurological function and involves multiorgan dysfunction. There are long-term complications such as cerebral palsy and developmental delay. Cardiac, renal, neurological and other organ dysfunctions are well described. Haematological dysfunction is relatively common and includes anaemia, thrombocytopenia, monocyte and neutrophil activation, hypofibrinogenemia and coagulopathy. There is a lack of consensus definitions of hematological parameters and optimal levels for intervention due to the lack of interventional studies in term neonates and the lack of knowledge of the optimal values during therapeutic hypothermia. However, derangements in hematological values are also associated with neurodevelopmental outcomes. This article outlines the different hematological complications associated with NE and therapeutic hypothermia and suggests a framework for management.

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.

Longitudinal assessment of cardiac function in infants with Down's syndrome using novel echocardiography techniques - project protocol.

Background: Down's syndrome (DS) is the most common chromosomal abnormality globally. Ireland has one of the highest rates of DS in the western world with an incidence of 1:444 live births. Congenital heart disease (CHD) and pulmonary hypertension (PH) are the commonest morbidities affecting the cardiovascular system in DS. PH is associated with significant morbidity and an increase risk of mortality. The impact of the diagnosis of DS, the presence of CHD and the associated PH on myocardial function during transition and over the first 2 years of age in this population is not well defined and warrants further study. In particular, serial measurements of pulmonary pressures in this population over the first week of age are lacking. This study aims to characterise myocardial function and pulmonary haemodynamics in infants with Down syndrome during the transitional period (over the first week of age) and throughout the first two years of age. Methods: A prospective, observational study utilising novel echocardiography techniques to assess myocardial function and pulmonary haemodynamics over the first two years of age in infants with Down Syndrome. A population of healthy infants without CHD or a diagnosis of DS will be recruited as controls. This study will be conducted across the three Dublin maternity units. Discussion: In total, 70 babies with DS have been enrolled into this study with 292 echocardiograms performed to date. Further evaluation of cardiac performance in DS infants with and without CHD may yield more insight into the pathophysiology of cardiac dysfunction and pulmonary hypertension that are recognised features in these patients. This could aid in our ability to monitor and treat patients, as well as improve our ability to predict outcomes.

Preterm neonates benefit from low prophylactic platelet transfusion threshold despite varying risk of bleeding or death.

The Platelets for Neonatal Thrombocytopenia (PlaNeT-2) trial reported an unexpected overall benefit of a prophylactic platelet transfusion threshold of 25 × 109/L compared with 50 × 109/L for major bleeding and/or mortality in preterm neonates (7% absolute-risk reduction). However, some neonates in the trial may have experienced little benefit or even harm from the 25 × 109/L threshold. We wanted to assess this heterogeneity of treatment effect in the PlaNet-2 trial, to investigate whether all preterm neonates benefit from the low threshold. We developed a multivariate logistic regression model in the PlaNet-2 data to predict baseline risk of major bleeding and/or mortality for all 653 neonates. We then ranked the neonates based on their predicted baseline risk and categorized them into 4 risk quartiles. Within these quartiles, we assessed absolute-risk difference between the 50 × 109/L- and 25 × 109/L-threshold groups. A total of 146 neonates died or developed major bleeding. The internally validated C-statistic of the model was 0.63 (95% confidence interval, 0.58-0.68). The 25 × 109/L threshold was associated with absolute-risk reduction in all risk groups, varying from 4.9% in the lowest risk group to 12.3% in the highest risk group. These results suggest that a 25 × 109/L prophylactic platelet count threshold can be adopted in all preterm neonates, irrespective of predicted baseline outcome risk. Future studies are needed to improve the predictive accuracy of the baseline risk model. This trial was registered at www.isrctn.com as #ISRCTN87736839.

Platelet transfusion thresholds in neonatal medicine.

Thrombocytopenia is common in preterm neonates. Thresholds for prophylactic platelet transfusion vary widely due to lack of evidence. The results of the PlaNet-2/MATISSE Study identified harm in the form of mortality and major bleed in babies prophylactically transfused below a platelet count of 50 × 109/L compared to 25 × 109/L. Neonatal platelet transfusions are administered at volumes based on historical practice which greatly exceed those routinely used in adults. Rate of transfusion is also based around practice in trauma and does not take into account the physiology of the preterm infant. There are multiple ways in which platelets may be mediating harm and this review discusses these potential mechanisms including immunological, inflammatory and blood group incompatibility. Much of the difficulty in assessing harm relates to problems in classification of transfusion-associated adverse events in babies. Thrombocytopenia and timing, efficacy and adverse effects of platelet transfusion are poorly understood. Further research is essential.

Flow cytometry for near-patient testing in premature neonates reveals variation in platelet function: a novel approach to guide platelet transfusion.

BACKGROUND: Neonatal haemorrhaging is often co-observed with thrombocytopenia; however, no evidence of a causal relationship with low platelet count has been reported. Regardless, the administration of a platelet transfusion is often based upon this parameter. Accurate measurement of platelet function in small volumes of adult blood samples by flow cytometry is well established and we propose that the use of the same technology could provide complementary information to guide the administration of platelet transfusions in premature neonates. METHODS: In 28 neonates born at 27-41 weeks gestation, platelet function after stimulation agonists was measured using fibrinogen binding and P-selectin expression (a marker of degranulation). RESULTS: Platelets of neonates with gestation of ≤36 weeks (n = 20) showed reduced fibrinogen binding and degranulation with ADP, and reduced degranulation with CRP-XL. Degranulation Scores of 7837 ± 5548, 22,408 ± 5301 and 53,131 ± 12,102 (mean ± SEM) identified significant differences between three groups: <29, 29-36 and >36 weeks gestation). Fibrinogen binding and degranulation responses to ADP were significantly reduced in suspected septic neonates (n = 6) and the Fibrinogen Binding scores clearly separated the septic and healthy group (88.2 ± 10.3 vs 38.6 ± 12.2, P = 0.03). CONCLUSIONS: Flow cytometric measurement of platelet function identified clinically different neonatal groups and may eventually contribute to assessment of neonates requiring platelet transfusion.

Randomized Trial of Platelet-Transfusion Thresholds in Neonates.

BACKGROUND: Platelet transfusions are commonly used to prevent bleeding in preterm infants with thrombocytopenia. Data are lacking to provide guidance regarding thresholds for prophylactic platelet transfusions in preterm neonates with severe thrombocytopenia. METHODS: In this multicenter trial, we randomly assigned infants born at less than 34 weeks of gestation in whom severe thrombocytopenia developed to receive a platelet transfusion at platelet-count thresholds of 50,000 per cubic millimeter (high-threshold group) or 25,000 per cubic millimeter (low-threshold group). Bleeding was documented prospectively with the use of a validated bleeding-assessment tool. The primary outcome was death or new major bleeding within 28 days after randomization. RESULTS: A total of 660 infants (median birth weight, 740 g; and median gestational age, 26.6 weeks) underwent randomization. In the high-threshold group, 90% of the infants (296 of 328 infants) received at least one platelet transfusion, as compared with 53% (177 of 331 infants) in the low-threshold group. A new major bleeding episode or death occurred in 26% of the infants (85 of 324) in the high-threshold group and in 19% (61 of 329) in the low-threshold group (odds ratio, 1.57; 95% confidence interval [CI], 1.06 to 2.32; P=0.02). There was no significant difference between the groups with respect to rates of serious adverse events (25% in the high-threshold group and 22% in the low-threshold group; odds ratio, 1.14; 95% CI, 0.78 to 1.67). CONCLUSIONS: Among preterm infants with severe thrombocytopenia, those randomly assigned to receive platelet transfusions at a platelet-count threshold of 50,000 per cubic millimeter had a significantly higher rate of death or major bleeding within 28 days after randomization than those who received platelet transfusions at a platelet-count threshold of 25,000 per cubic millimeter. (Funded by the National Health Service Blood and Transplant Research and Development Committee and others; Current Controlled Trials number, ISRCTN87736839 .).