A new formula for blood transfusion volume in the critically ill

The need for blood transfusion therapy is associated with increased mortality in children with traumatic brain injury

OBJECTIVE

Blood transfusion therapy (BTT) is widely used in trauma patients. However, the adverse effects of BTT in pediatric trauma patients with traumatic brain injury (TBI) were poorly studied. The objective of this study is to evaluate the effect of BTT on mortality in children with severe TBI.

METHODS

In this retrospective cohort analysis, we analyzed 2012 and 2016 Kids' Inpatient Databases and used a weighted sample to obtain national outcome estimates. We included children aged 1 month to 21 years with TBI who were mechanically ventilated, considered severe TBI; we then compared the demographics, comorbidities, and mortality rates of those patients who had undergone BTT to those who did not. Statistical analysis was performed using the chi-squared test and regression models. In addition, in a correlative propensity score matched analysis, cases (BTT) were matched 1:1 with controls (non-BTT) based on age, gender, hospital region, income quartiles, race, and All Patients Refined Diagnosis Related Groups (APRDRG) severity of illness scores to minimize the effect of confounding variables between the groups.

RESULTS

Out of 87,980 children with a diagnosis of TBI, 17,199 (19.5%) with severe TBI were included in the analysis. BTT was documented in 3184 (18.5%) children. Among BTT group, the mortality was higher compared to non-BTT group [31.6% (29.7-33.5%) vs. 14.4 (13.7-15.1%), (OR 2.2, 95% CI 1.9-2.6; p<0.05)]. In the BTT group, infants and adolescents, white race, APRDRG severity of illness, cardiac arrest, platelet, and coagulation factor transfusions were associated with higher mortality. In a propensity-matched analysis, BTT associated with a higher risk of mortality (32.1% [30.1-34.2] vs. 17.4% [15.8-19.1], p<0.05; OR: 2.2, 95% CI: 1.9-2.6).

CONCLUSION

In children with severe TBI, blood transfusion therapy is associated with higher mortality.

Transfusion management of severe anaemia in African children: a consensus algorithm

The phase III Transfusion and Treatment of severe anaemia in African Children Trial (TRACT) found that conservative management of uncomplicated severe anaemia [haemoglobin (Hb) 40-60 g/l] was safe, and that transfusion volume (20 vs. 30 ml/kg whole blood equivalent) for children with severe anaemia (Hb <60 g/l) had strong but opposing effects on mortality, depending on fever status (>37·5°C). In 2020 a stakeholder meeting of paediatric and blood transfusion groups from Africa reviewed the results and additional analyses. Among all 3196 children receiving an initial transfusion there was no evidence that nutritional status, presence of shock, malaria parasite burden or sickle cell disease status influenced outcomes or modified the interaction with fever status on volume required. Fever status at the time of ordering blood was a reliable determinant of volume required for optimal outcome. Elevated heart and respiratory rates normalised irrespective of transfusion volume and without diuretics. By consensus, a transfusion management algorithm was developed, incorporating three additional measurements of Hb post-admission, alongside clinical monitoring. The proposed algorithm should help clinicians safely implement findings from TRACT. Further research should assess its implementation in routine clinical practice.

Transfusion support: Considerations in pediatric populations

Over 400,000 units of blood and blood products are transfused to pediatric patients annually, yet only sparse high-quality data exist to guide the preparation and administration of blood products in this population. The direct application of data from studies in adult patients should be undertaken with caution, as there are dissimilarities in the pathology and physiology between adult and pediatric patients. We provide an overview of available evidence in the field of pediatric transfusion medicine, summarizing indications for blood product transfusion, thresholds for transfusion and indications for blood product modifications.

Transfusion Volume for Children with Severe Anemia in Africa

BACKGROUND

Severe anemia (hemoglobin level, <6 g per deciliter) is a leading cause of hospital admission and death in children in sub-Saharan Africa. The World Health Organization recommends transfusion of 20 ml of whole-blood equivalent per kilogram of body weight for anemia, regardless of hemoglobin level.

METHODS

In this factorial, open-label trial, we randomly assigned Ugandan and Malawian children 2 months to 12 years of age with a hemoglobin level of less than 6 g per deciliter and severity features (e.g., respiratory distress or reduced consciousness) to receive immediate blood transfusion with 20 ml per kilogram or 30 ml per kilogram. Three other randomized analyses investigated immediate as compared with no immediate transfusion, the administration of postdischarge micronutrients, and postdischarge prophylaxis with trimethoprim-sulfamethoxazole. The primary outcome was 28-day mortality.

RESULTS

A total of 3196 eligible children (median age, 37 months; 2050 [64.1%] with malaria) were assigned to receive a transfusion of 30 ml per kilogram (1598 children) or 20 ml per kilogram (1598 children) and were followed for 180 days. A total of 1592 children (99.6%) in the higher-volume group and 1596 (99.9%) in the lower-volume group started transfusion (median, 1.2 hours after randomization). The mean (±SD) volume of total blood transfused per child was 475±385 ml and 353±348 ml, respectively; 197 children (12.3%) and 300 children (18.8%) in the respective groups received additional transfusions. Overall, 55 children (3.4%) in the higher-volume group and 72 (4.5%) in the lower-volume group died before 28 days (hazard ratio, 0.76; 95% confidence interval [CI], 0.54 to 1.08; P = 0.12 by log-rank test). This finding masked significant heterogeneity in 28-day mortality according to the presence or absence of fever (>37.5°C) at screening (P=0.001 after Sidak correction). Among the 1943 children (60.8%) without fever, mortality was lower with a transfusion volume of 30 ml per kilogram than with a volume of 20 ml per kilogram (hazard ratio, 0.43; 95% CI, 0.27 to 0.69). Among the 1253 children (39.2%) with fever, mortality was higher with 30 ml per kilogram than with 20 ml per kilogram (hazard ratio, 1.91; 95% CI, 1.04 to 3.49). There was no evidence of differences between the randomized groups in readmissions, serious adverse events, or hemoglobin recovery at 180 days.

CONCLUSIONS

Overall mortality did not differ between the two transfusion strategies. (Funded by the Medical Research Council and Department for International Development, United Kingdom; TRACT Current Controlled Trials number, ISRCTN84086586.).

Comprehensive Analysis of Liberal and Restrictive Transfusion Strategies in Pediatric Intensive Care Unit

BACKGROUND

We prospectively compared restrictive and liberal transfusion strategies for critically ill children regarding hemodynamic and laboratory parameters.

METHODS

A total of 180 children requiring packed red blood cells (PRBCs) were randomized into two groups: the liberal transfusion strategy group (transfusion trigger < 10 g/dL, Group 1) and the restrictive transfusion strategy group (transfusion trigger ≤ 7 g/dL, Group 2). Basal variables including venous/arterial hemoglobin, hematocrit and lactate levels; stroke volume; and cardiac output were recorded at the beginning and end of the transfusion. Oxygen saturation, noninvasive total hemoglobin, noninvasive total oxygen content, perfusion index (PI), heart rate and systolic and diastolic blood pressures were assessed via the Radical-7 Pulse co-oximeter (Masimo, Irvine, CA, USA) with the Root monitor, initially and at 4 h.

RESULTS

In all, 160 children were eligible for final analysis. The baseline hemoglobin level for the PRBC transfusion was 7.38 ± 0.98 g/dL for all patients. At the end of the PRBC transfusion, cardiac output decreased by 9.9% in Group 1 and by 24% in Group 2 (p  < 0.001); PI increased by 10% in Group 1 and by 45% in Group 2 (p  < 0.001). Lactate decreased by 9.8% in Group 1 and by 31.68% in Group 2 (p < 0.001).

CONCLUSION

Restrictive blood transfusion strategy is better than liberal transfusion strategy with regard to the hemodynamic and laboratory values during the early period. PI also provides valuable information regarding the efficacy of PRBC transfusion in clinical practice.

Variation in Transfusion Requirements Among Children With Thalassemia on Regular Transfusion Programs: Which Formula Closely Predicts the Actual Requirements?

BACKGROUND

Various different formulae are used to calculate blood transfusion volumes in thalassemia. Using the right formula will avoid iron overload and complications of undertransfusion.

OBSERVATIONS

Five years of transfusion data in 11 children with thalassemia showed that no single formula-calculated transfusion volumes accurately. The formula used in the United Kingdom with a hematocrit of the transfused blood of 0.6: (0.4×body weight×desired raise in hemoglobin [g/L]) yielded a volume closest to empirically determined requirements on average. Transfusion factors ranging from 0.3 to 0.48 were calculated as necessary to achieve the required volume for the individual patient.

CONCLUSIONS

To meet transfusion requirements, individualization of formulas by establishment of the transfusion factor for each patient is helpful.

Blood transfusion in acute and chronic pediatric settings: beliefs and practices

BACKGROUND

Blood has been imbued with powerful connotations through history and across cultures. Currently bestowed with scientific meaning, blood nevertheless carries symbolic resonance. This study examines these representations among practitioners and sheds light on the clinical and nonclinical factors that guide blood transfusion (BT) decision-making in Quebec, Canada.

STUDY DESIGN AND METHODS

With a qualitative exploratory study design, data were collected in the pediatric intensive care unit and the hematology-oncology unit of Sainte-Justine Hospital in 2009. A total of fifteen 1-hour-long semistructured interviews were conducted with physicians.

RESULTS

Physicians affirm that the symbolic connotations of blood found in the lay population do not influence their transfusion decisions. However, there are other "social" and "cultural' aspects that influence these practices. Also, BT strategies remain diverse across units. Practitioners perceive these situations as resulting from insufficient training and by the existence of an "oral tradition" and a professional culture that are resistant to change.

CONCLUSION

BT practices differ within and across units. Many dimensions intervene in the decision to transfuse, from individual clinical appreciation and local unit "culture" to formal and ad hoc training. Consistent change in BT can only occur with the implementation of norms and guidelines that are endorsed by key influential figures. An extensive multicentered study is necessary to better understand how social and cultural factors affect BT practices. This knowledge will sustain an enlightened clinical practice and lead to the recognition that peer practices are also embedded in professional cultures.

Ultrasonographic assessment of splenic volume at presentation and after anti-malarial therapy in children with malarial anaemia

Background

Splenic enlargement is a component of the host response to malaria and may also influence the genesis and progression of malarial anaemia. Few cross-sectional and no longitudinal studies have assessed the relationship between splenic volume measured ultrasonographically and haemoglobin concentrations in children with malaria.

Methods

Fifteen Papua New Guinean children with severe malarial anaemia (SMA; haemoglobin <50 g/L) and ten with moderate malarial anaemia (MMA; 51–99 g/L) were recruited. The SMA patients were given intramuscular artemether followed by oral artemisinin combination therapy (ACT), and were transfused one unit of packed cells 0.3-4.0 days post-admission. The MMA patients were treated with ACT. Splenic enlargement (Hackett’s grade, subcostal distance and ultrasonographically determined volume) and haemoglobin concentrations were measured on days 0, 1, 2, 3, 7, 14, 28, and 42.

Results

Associations between Hackett’s grade, subcostal distance and splenic volume were modest (r_s ≤ 0.62, P <0.001). Baseline splenic volume was not associated with age or haemoglobin (P ≥0.90). Mean splenic volume had fallen by approximately 50 % at day 14 in children with MMA (P ≤0.011 vs days 0, 1 and 2), but there was no change in the SMA group (P ≥0.30). There was no change in haemoglobin in the MMA group during follow-up but a rise in the SMA group to day 7 (P ≤0.05 vs days 0, 1, 2, and 3) which paralleled the packed cell volume transfused.

Conclusions

Clinical assessment of splenomegaly is imprecise compared with ultrasonography. Serial splenic volumes and haemoglobin concentrations suggest that the spleen does not influence post-treatment haemoglobin, including after transfusion.

Blood component transfusion increases the risk of death in children with traumatic brain injury

BACKGROUND

Blood transfusion has been associated with worse outcomes in adult trauma patients with traumatic brain injury (TBI). However, the effects in injured children have not been evaluated. We hypothesize that blood transfusion is also associated with worse outcomes in children with TBI.

METHODS

A retrospective review of the trauma database at two Level I pediatric trauma centers was performed. We reviewed all patients 18 years and younger with TBI, who survived at least 24 hours, from 2002 to 2011. Exclusion criteria include those who underwent craniotomy, thoracotomy, exploratory laparotomy, and any orthopedic procedure.

RESULTS

A total of 1,607 children with TBI were included in the study population (mean age, 6.4 [5.7] years; 65% male), 178 of whom received a blood transfusion. Mean Injury Severity Score (ISS) was 16.5 (9.1). Patients who received a transfusion had a higher ISS than those who did not (26.7 vs. 15.3). After controlling for age, sex, ISS, Glasgow Coma Scale (GCS) score on presentation, and mechanism of injury, patients who received a blood transfusion were more likely to be admitted to the intensive care unit (p < 0.0001), less likely to survive to hospital discharge (p = 0.02), more likely to be discharged to a rehabilitation facility (p = 0.01) and be dependent on caretakers at follow-up (p < 0.0001), as well as more likely to develop urinary tract infection (p = 0.02) and bacteremia (p = 0.02) during their hospital stay. These differences in outcomes among those who did and did not receive a blood transfusion began to disappear in patients with a nadir hemoglobin of less than 8.0 g/dL.

CONCLUSION

Pediatric patients sustaining TBI who receive blood transfusion and do not require operative intervention have worse outcomes compared with patients who do not receive transfusion. This includes an increased risk of death. These data suggest that a transfusion trigger of hemoglobin level at 8.0 g/dL in injured children with TBI may be beneficial.

LEVEL OF EVIDENCE

Epidemiologic study, level III. Therapeutic study, level IV.

Phase II trial of standard versus increased transfusion volume in Ugandan children with acute severe anemia

BACKGROUND

Severe anemia (SA, hemoglobin <6 g/dl) is a leading cause of pediatric hospital admission in Africa, with significant in-hospital mortality. The underlying etiology is often infectious, but specific pathogens are rarely identified. Guidelines developed to encourage rational blood use recommend a standard volume of whole blood (20 ml/kg) for transfusion, but this is commonly associated with a frequent need for repeat transfusion and poor outcome. Evidence is lacking on what hemoglobin threshold criteria for intervention and volume are associated with the optimal survival outcomes.

METHODS

We evaluated the safety and efficacy of a higher volume of whole blood (30 ml/kg; Tx30: n = 78) against the standard volume (20 ml/kg; Tx20: n = 82) in Ugandan children (median age 36 months (interquartile range (IQR) 13 to 53)) for 24-hour anemia correction (hemoglobin >6 g/dl: primary outcome) and 28-day survival.

RESULTS

Median admission hemoglobin was 4.2 g/dl (IQR 3.1 to 4.9). Initial volume received followed the randomization strategy in 155 (97%) patients. By 24-hours, 70 (90%) children in the Tx30 arm had corrected SA compared to 61 (74%) in the Tx20 arm; cause-specific hazard ratio = 1.54 (95% confidence interval 1.09 to 2.18, P = 0.01). From admission to day 28 there was a greater hemoglobin increase from enrollment in Tx30 (global P <0.0001). Serious adverse events included one non-fatal allergic reaction and one death in the Tx30 arm. There were six deaths in the Tx20 arm (P = 0.12); three deaths were adjudicated as possibly related to transfusion, but none secondary to volume overload.

CONCLUSION

A higher initial transfusion volume prescribed at hospital admission was safe and resulted in an accelerated hematological recovery in Ugandan children with SA. Future testing in a large, pragmatic clinical trial to establish the effect on short and longer-term survival is warranted.

TRIAL REGISTRATION

ClinicalTrials.Gov identifier: NCT01461590 registered 26 October 2011.

Assessment of five formulae to predict post-transfusion packed cell volume in cats

This retrospective study aimed to identify the most accurate formula for estimating the increase in packed cell volume (PCV) after whole blood transfusion of cats, as several formulae have been reported but not validated. Forty cats, of varying breeds and gender, were included from two referral institutions after database searches over a 13 year period. Five formulae were used to calculate an estimated post-transfusion PCV based on the re-working of formulae for determining the volume of donor blood to be transfused; three formulae were derived from those previously reported in the feline literature and two from human paediatric medicine, where a similar mean blood volume has been described. Cats were subdivided into two groups, the first consisting of 17 cats with non-regenerative anaemia and the second consisting of 23 cats with ongoing losses such as haemolysis and haemorrhage; it was hypothesised that formulae could be more accurate for group 1 cats, whereas formulae applied to group 2 cats could have overestimated the post-transfusion PCV. Bland–Altman analysis was performed for all cats to compare the actual increase in PCV with the calculated increase for the five formulae. Formula 1 (PCV % increase = volume of blood transfused in ml/2 × bodyweight in kg) performed best overall and is easy to calculate; however, no single formula was highly accurate at predicting the PCV increase after whole blood transfusion in cats and, owing to the wide confidence intervals, these formulae should be applied judiciously in the clinical setting.

Fluid homeostasis in the neonate

The physiology of the neonate is ideally suited to the transition to extrauterine life followed by a period of rapid growth and development. Intravenous fluids and electrolytes should be prescribed with care in the neonate. Sodium and water requirements in the first few days of life are low and should be increased after the postnatal diuresis. Expansion of the extracellular fluid volume prior to the postnatal diuresis is associated with poor outcomes, particularly in preterm infants. Newborn infants are prone to hypoglycemia and require a source of intravenous glucose if enteral feeds are withheld. Anemia is common, and untreated is associated with poor outcomes. Liberal versus restrictive transfusion practices are controversial, but liberal transfusion practices (accompanied by measures to minimize donor exposure) may be associated with improved long-term outcomes. Intravenous crystalloids are as effective as albumin to treat hypotension, and semi-synthetic colloids cannot be recommended at this time. Inotropes should be used to treat hypotension unresponsive to intravenous fluid, ideally guided by assessment of perfusion rather than blood pressure alone. Noninvasive methods of assessing cardiac output have been validated in neonates. More studies are required to guide fluid management in neonates, particularly in those with sepsis or undergoing surgery. A balanced salt solution such as Hartmann's or Plasmalyte should be used to replace losses during surgery (and blood or coagulation factors as indicated). Excessive fluid administration during surgery should be avoided.

Critically ill children: to transfuse or not to transfuse packed red blood cells, that is the question

OBJECTIVES

This article summarizes the current data on packed red blood cell transfusion in the pediatric intensive care unit setting to help providers make evidence-based decisions regarding packed red blood cell transfusions.

DATA SOURCES

Review of the literature, including PubMed, citations from relevant articles, and some articles that have been particularly relevant in adult critical care practice regarding packed red blood cell transfusion.

CONCLUSIONS

The use of packed red blood cell transfusions is common in the pediatric intensive care unit setting. However, until recently there have been little data to guide providers in this practice. Studies in adult intensive care units have shown less favorable outcomes in patients who received packed red blood cell transfusions. This has led to renewed questioning of the practice of packed red blood cell transfusion in critically ill pediatric patients. New data indicate that using a hemoglobin transfusion threshold of >7 g/dL does not yield improved outcomes. Furthermore, smaller studies have suggested that pediatric intensive care unit patients may be at an increased risk for morbidity and mortality when undergoing transfusion.

Use of Blood Products

Patients in the pediatric intensive care unit (PICU) frequently receive transfusions of blood products. While these therapies are often beneficial, they can be associated with significant, yet often overlooked, risks. Clinical guidelines for blood product transfusions must be well defined in order to prevent misuse of this limited resource. It is important for the intensivist to have a thorough understanding of the indications for specific blood products, and the transfusion needs of particular patient populations.

Red blood cell transfusion in critically ill children: a narrative review

OBJECTIVE

To review the pathophysiology of anemia, as well as transfusion-related complications and indications for red blood cell (RBC) transfusion, in critically ill children. Although allogeneic blood has become increasingly safer from infectious agents, mounting evidence indicates that RBC transfusions are associated with complications and unfavorable outcomes. As a result, there has been growing interest and efforts to limit RBC transfusion, and indications are being revisited and revamped. Although a so-called restrictive RBC transfusion strategy has been shown to improve morbidity and mortality in critically ill adults, there have been relatively few studies on RBC transfusion performed in critically ill children.

DATA SOURCES

Published literature on transfusion medicine and outcomes of RBC transfusion. STUDY SELECTION, DATA EXTRACTION, AND SYNTHESIS: After a brief overview of physiology of oxygen transportation, anemia compensation, and current transfusion guidelines based on available literature, risks and outcomes of transfusion in general and in critically ill children are summarized in conjunction with studies investigating the safety of restrictive transfusion strategies in this patient population.

CONCLUSIONS

The available evidence does not support the extensive use of RBC transfusions in general or critically ill patients. Transfusions are still associated with risks, and although their benefits are established in limited situations, the associated negative outcomes in many more patients must be closely addressed. Given the frequency of anemia and its proven negative outcomes, transfusion decisions in the critically ill children should be based on individual patient's characteristics rather than generalized triggers, with consideration of potential risks and benefits, and available blood conservation strategies that can reduce transfusion needs.

Are red blood cell transfusions associated with nosocomial infections in pediatric intensive care units?

OBJECTIVES

To determine whether red blood cell transfusion is similarly associated with nosocomial infections in pediatric intensive care unit patients and whether reduced lymphocyte numbers is a possible mechanism. In adult studies, red blood cell transfusions are associated with nosocomial infections.

DESIGN

Historical cohort study.

SETTING

Single-center, mixed medical-surgical, closed pediatric intensive care unit of a tertiary university-affiliated children's hospital.

PATIENTS

All patients < or = 18 yrs old admitted to the pediatric intensive care unit during a 6-month period from January 1 to July 3, 2005.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Nosocomial infections (respiratory, urinary tract, and bloodstream infections) were the primary outcome measure and were defined as post transfusion if occurring within 14 days after red blood cell transfusion. Of the 209 subjects enrolled, 32 (15%) acquired nosocomial infections and 45 (22%) received red blood cell transfusions. Patients with versus without nosocomial infections had received red blood cell transfusions significantly more often (odds ratio, 18.0; 95% confidence interval, 7.6-45.9; p < .001). In a dose-dependence analysis, we found that patients receiving > or = 3 red blood cell transfusions had a similar prevalence of nosocomial infections compared with those receiving one to two red blood cell transfusions (61% vs. 44%, p = .365), but greater mortality (22% vs. 0%, p = .04). In a multiple logistic regression analysis controlling for gender, age, pediatric intensive care unit length of stay, presence of an invasive catheter, mechanical ventilation, and surgery, red blood cell transfusion remained independently associated with risk of nosocomial infection (odds ratio, 3.73; 95% confidence interval, 1.19-11.85, p = .023). Transfused subjects had lower absolute lymphocyte counts compared with nontransfused subjects (1605 vs. 2054/microL, p = .041), but similar total white blood cell counts (10.4 vs. 11.4 x 10/microL, p = .52).

CONCLUSION

Red blood cell transfusion in pediatric intensive care unit patients is associated with an increased risk of nosocomial infections.

Anemia of critical illness

Anemia of critical illness, a commonly encountered clinical situation, is hematologically similar to that of chronic anemia, except that the onset is generally sudden. The etiology is usually multifactorial, occurring as a consequence of direct inhibitory effects of inflammatory cytokines, erythropoietin deficiency, blunted erythropoietic response, blood loss, nutritional deficiencies, and renal insufficiency. Although anemia is not well tolerated by critically ill patients, aggressive treatment of anemia can be just as detrimental as no treatment. Different types of anemia may coexist in a patient in the intensive care unit, making diagnosis and differentiation among these anemias complex, therefore requiring good diagnostic skills. Although several therapeutic options are available to treat anemia, critically ill patients often receive a transfusion, and yet, most recent studies indicate that blood transfusions in critically ill patients are associated with worse outcomes, including higher morbidity and mortality. These studies have generated interest in the administration of exogenous erythropoietin and iron therapy. Unfortunately, the accurate determination of iron status can be a rather difficult task, an undertaking that is made even more difficult by the presence of comorbid conditions that can affect the commonly used parameters for guiding iron therapy. The use of erythropoiesis-stimulating agents is rapidly gaining acceptance, although they also present potential problems of their own.

Anemia, blood loss, and blood transfusions in North American children in the intensive care unit

RATIONALE

Minimizing exposure of children to blood products is desirable.

OBJECTIVES

We aimed to understand anemia development, blood loss, and red blood cell (RBC) transfusions in the pediatric intensive care unit (PICU).

METHODS

Prospective, multicenter, 6-month observational study in 30 PICUs. Data were collected on consecutive children (<18 yr old) in the PICU for 48 hours or more.

MEASUREMENTS AND MAIN RESULTS

Anemia development, blood loss, and RBC transfusions were measured. A total of 977 children were enrolled. Most (74%) children were anemic in the PICU (33% on admission, 41% developed anemia). Blood draws accounted for 73% of daily blood loss; median loss was 5.0 ml/day. Forty-nine percent of children received transfusions; 74% of first transfusions were on Days 1-2. After adjusting for age and illness severity, compared with nontransfused children, children who underwent transfusion had significantly longer days of mechanical ventilation (2.1 d, P < 0.001) and PICU stay (1.8 d, P = 0.03), and had increased mortality (odds ratio [OR], 11.6; 95% confidence interval [CI], 1.43-90.9; P = 0.02), nosocomial infections (OR, 1.9; 95% CI, 1.2-3.0; P = 0.004), and cardiorespiratory dysfunction (OR, 2.1; 95% CI, 1.5-3.0; P < 0.001). High blood loss per kilogram body weight from blood draws (OR, 1.11; 95% CI, 1.03-1.2; P = 0.01) was associated with RBC transfusion more than 48 hours after admission. The most common indication for transfusion was low hemoglobin (42%). Pretransfusion hemoglobin values varied greatly (mean, 9.7 +/- 2.7 g/dl).

CONCLUSIONS

Critically ill children are at significant risk for developing anemia and receiving blood transfusions. Transfusion in the PICU was associated with worse outcomes. It is imperative to minimize blood loss from blood draws and to set clear transfusion thresholds.

Red blood cell transfusion in clinical practice

Every year, about 75 million units of blood are collected worldwide. Red blood cell (RBC) transfusion is one of the few treatments that adequately restore tissue oxygenation when oxygen demand exceeds supply. Although the respiratory function of blood has been studied intensively, the trigger for RBC transfusion remains controversial, and doctors rely primarily on clinical experience. Laboratory assays that indicate failing tissue oxygenation would be ideal to guide the need for transfusion, but none has proved easy, reproducible, and sensitive to regional tissue hypoxia. The clinical importance of the RBCs storage lesion (ie, the time-dependent metabolic, biochemical, and molecular changes that stored blood cells undergo) is poorly understood. RBCs can be filtered, washed, frozen, or irradiated for specific indications. Donor screening and testing have dramatically reduced infectious risks in the developed world, but infection remains a major hazard in developing countries, where 13 million units of blood are not tested for HIV or hepatitis viruses. Pathogen inactivation techniques are in clinical trials for RBCs, but none is available for use. Despite serious immunological and non-immunological complications, RBC transfusion holds a therapeutic index that exceeds that of many common medications.

Transfusion strategies for patients in pediatric intensive care units

BACKGROUND

The optimal hemoglobin threshold for erythrocyte transfusions in critically ill children is unknown. We hypothesized that a restrictive transfusion strategy of using packed red cells that were leukocyte-reduced before storage would be as safe as a liberal transfusion strategy, as judged by the outcome of multiple-organ dysfunction.

METHODS

In this noninferiority trial, we enrolled 637 stable, critically ill children who had hemoglobin concentrations below 9.5 g per deciliter within 7 days after admission to an intensive care unit. We randomly assigned 320 patients to a hemoglobin threshold of 7 g per deciliter for red-cell transfusion (restrictive-strategy group) and 317 patients to a threshold of 9.5 g per deciliter (liberal-strategy group).

RESULTS

Hemoglobin concentrations were maintained at a mean (+/-SD) level that was 2.1+/-0.2 g per deciliter lower in the restrictive-strategy group than in the liberal-strategy group (lowest average levels, 8.7+/-0.4 and 10.8+/-0.5 g per deciliter, respectively; P<0.001). Patients in the restrictive-strategy group received 44% fewer transfusions; 174 patients (54%) in that group did not receive any transfusions, as compared with 7 patients (2%) in the liberal-strategy group (P<0.001). New or progressive multiple-organ dysfunction syndrome (the primary outcome) developed in 38 patients in the restrictive-strategy group, as compared with 39 in the liberal-strategy group (12% in both groups) (absolute risk reduction with the restrictive strategy, 0.4%; 95% confidence interval, -4.6 to 5.4). There were 14 deaths in each group within 28 days after randomization. No significant differences were found in other outcomes, including adverse events.

CONCLUSIONS

In stable, critically ill children a hemoglobin threshold of 7 g per deciliter for red-cell transfusion can decrease transfusion requirements without increasing adverse outcomes. (Controlled-trials.com number, ISRCTN37246456 [controlled-trials.com].).

Calculating the required transfusion volume in children

BACKGROUND

The traditional method of calculating blood volume for pediatric transfusion in the UK is weight (kg) x aimed increment in hemoglobin concentration (Hb; g/dL) x the transfusion factor, usually quoted at 3 or 4. This equation is without evidence base. The aim was to assess how the volume of red cells (RBCs) affects the increase in serum Hb in children and to devise a formula that allows accurate volume calculation.

STUDY DESIGN AND METHODS

All pediatric intensive care charts for 2 years were examined retrospectively. The immediate pre- and posttransfusion Hb estimations and the precise volumes of RBC transfused were recorded. Fluid boluses and hemorrhagic loss during the transfusion were documented.

RESULTS

A total of 7679 patient charts were examined with a total of 564 transfusions. All patients who were bleeding, had drain losses, or had concurrent colloid infusions were excluded, giving 379 data points. The correlation gradient between mL per kg blood transfused and increase in Hb was 5.02. There was no significant association between effect and patient weight, age, starting Hb, transfusion time, or sex. No significant difference was found in Hb at 1 and 7 hours posttransfusion.

CONCLUSIONS

The following equation should be used to calculate transfusion volumes: weight (kg) x increment in Hb (g/dL) x 3/(hematocrit [Hct] level of RBCs). This predicts that with a UK standard Hct of 0.6, 10 mL/kg gives an increment of 2 g/dL. Care must be taken not to risk hypervolemia, while minimizing donor exposure. Hb estimation 1 hour after transfusion is the same as 7 hours after transfusion.