Is it possible to predict the blood volume of a sick preterm infant?

Blood volume reduction due to rapid plasma loss after birth in preterm piglets

BACKGROUND

Understanding changes in blood volume after preterm birth is critical to preventing cardiovascular deterioration in preterm infants. The aims were to determine if blood volume is higher in preterm than term piglets and if blood volume changes in the hours after birth.

METHODS

Paired blood volume measurements were conducted in preterm piglets (98/115d gestation, ~28wk gestation infant) at 0.5-5 h (n = 12), 0.5-9 h (n = 44) and 5-11 h (n = 7) after birth, and in a term cohort at 0.5-9 h (n = 40) while under intensive care.

RESULTS

At 30 min after birth, blood volume was significantly lower in preterm piglets compared to term piglets. By 9 h after birth, blood volume had reduced by 18% in preterm piglets and 13% in term piglets. By 5-9 h after birth, preterm piglets had significantly lower blood volumes than at term (61 ± 10 vs. 76 ± 11 mL/kg).

CONCLUSIONS

In contrast to clinical resources, preterm piglets have a lower blood volume than at term. Substantial reductions in blood volume after birth leave some preterm piglets hypovolemic. If this also occurs in preterm infants, this may have important clinical consequences. Modern studies of blood volume changes after birth are essential for improving preterm outcomes.

IMPACT

Preterm piglets do not have a higher blood volume than their term counterparts, in contrast to current clinical estimates. Rapid reduction in blood volume after birth leads to hypovolemia in some preterm piglets. There is a critical need to understand blood volume changes after birth in preterm infants in order to improve clinical management of blood volume.

Red cell infusion but not saline is effective for volume expansion in preterm piglets

BACKGROUND

A common first-line treatment for supporting cardiovascular function in preterm infants is volume expansion using saline, but this does not improve outcomes. This study aimed to determine if volume expansion with saline increases blood volume, blood pressure and cerebral oxygenation; and if volume expansion with packed red blood cells (RBC) is more effective. We hypothesized that RBC infusion is more effective than saline for increasing blood volume and maintaining cardiovascular function and cerebral oxygenation.

METHODS

Five groups of preterm piglets (98/115d gestation) were infused with saline (10 or 20 mL/kg) or RBC (10 or 20 mL/kg) or no treatment. Blood volume, blood pressure, central venous pressure, heart rate, carotid flow, cerebral oxygenation, arterial pH, base excess, and lactate levels were assessed for 6 h after treatment started.

RESULTS

Both RBC groups had significant increases in blood volume, and improved measures of cardiovascular function, cerebral oxygenation and metabolic acidosis. Saline infusion did not increase blood volume or measures of cardiovascular function, cerebral oxygenation or metabolic acidosis.

CONCLUSIONS

The results suggest that the deteriorating cardiovascular function in the hours after birth in preterm piglets, and possibly in premature babies, may be reversed or halted by more effective support of blood volume.

IMPACT

Blood volume decreases after birth in preterm piglets and this decrease is associated with deteriorating cardiovascular function and cerebral oxygenation. Infusion of saline does not increase blood volume nor prevent deterioration in cardiovascular function. Infusion of packed red blood cells results in an increase in blood volume and improvements in cardiovascular function and cerebral oxygenation. Deteriorating cardiovascular function in the hours after birth in preterm piglets, and possibly in human preterm neonates, may be reversed or halted by more effective support of blood volume.

Long-term outcomes of saline boluses in very preterm infants

BACKGROUND

Normal saline bolus is commonly used in clinical practice for treating hypotension in very preterm infants during resuscitation at an early age despite the paucity of high quality evidence supporting this practice.

OBJECTIVES

To determine the effects of early (<7 days after birth) saline boluses given to very preterm infant (VPI) from 23 to 31 weeks GA.

METHOD

This is a population-based cohort analysis of the use of normal saline boluses given to VPI. The outcomes were extracted from the Perinatal Follow-Up Program Database which included all VPI from Halifax County admitted to the NICU at the IWK Health Centre, Halifax, Nova Scotia, Canada between January 2006 to December 2010. We excluded infants with major congenital anomalies and those not offered resuscitation in the delivery room. Our primary outcome was the composite of death or disability by 18-36 months while secondary outcomes were neonatal death, BPD, CP, IVH, PVL, ROP, BSITD III (Bayley Scales of Infant and Toddler Development®, Third Edition) Cognitive, Motor and Language score.

RESULTS

Death or disability in those who received saline bolus occurred in 15 (53.6%) compared with 9 (32.1%) in non saline group. Significantly higher rates of CP (p = 0.04), lower scores on the BSITDIII for motor (p = 0.04) and language scales (p = 0.03) were noted for infants who received saline boluses. Cognitive scores approached significance (p = 0.05) with lower scores in the saline bolus group.

CONCLUSION

Significant differences were found between the two groups in terms of long term neurodevelopmental outcome and one of the short-term outcome (i.e. BPD). Given the limitations of this retrospective study and the small sample size, a larger cohort from Canadian Neonatal Network database is warranted to evaluate the effects of using normal saline boluses during early life on neurodevelopmental.

A method for red blood cell biotinylation in a closed system

BACKGROUND

Several circumstances require the accurate measurement of red blood cell (RBC) survival and clearance, such as determination of posttransfusion recovery of stored RBCs to investigate the effect of new additive solutions. To this end, biotin as a marker of RBCs to track donor RBCs in the blood of the recipient has been used in many studies. However, so far only experimental, nonvalidated, biotin-labeled red cell concentrates (RCCs) are transfused. The goal of this study was to produce a standardized biotin-labeled RCC product in a fast, simple, and sterile manner that can be used for clinical research and for the evaluation of new blood products according to Good Practice Guidelines (GPG) for blood establishments.

STUDY DESIGN AND METHODS

RCC fractions were labeled with two different concentrations of biotinylation reagent in a closed system, to prevent bacterial contamination of the end product. Using flow cytometry, the reproducibility and robustness of the biotin labeling was assessed, as well as the stability of the biotin label on the (un-)irradiated RCC fraction. Additionally, parameters such as phosphatidylserine (PS) exposure, sodium (Na), potassium (K), free hemoglobin, adenosine triphosphate (ATP), pH, and morphology were determined prior to and after biotin labeling to rule out detrimental effects of the labeling procedure on the RCC.

RESULTS

Our data show that RCCs can be labeled under sterile conditions in a closed system with two different biotinylation reagent concentrations, without affecting the biological activity.

CONCLUSION

An easy, rapid (<2 hr), and robust method was developed to manufacture biotin-labeled RCCs for clinical research compliant to GPG.

Red Blood Cell Transfusion in Preterm Infants: Current Evidence and Controversies

The current evidence regarding the indication, advantages and risks of red blood cell transfusion (RBCT) for preterm infants is discussed. This is an important area in Neonatology to be examined given that 90% of extremely low birth weight infants receive RBCT and many controversies remain regarding when to transfuse and the risks of RBCT. The various treatment thresholds and guidelines used are presented and we compare the short-term clinical benefits of liberal and restrictive RBCT in preterm infants; the majority of these are equivocal and sadly long-term outcome data is limited. The latest evidence on how anaemia and blood transfusion affect organ perfusion in preterm infants is presented. This is important when trying to establish the optimal trigger threshold for RBCT in preterm infants, especially because the knowledge about the adaptive physiological responses to anaemia in very low birth weight infants and the effects of RBCT at various levels of anaemia is also inadequate. Further research into the physiological adaptive response to anaemia of varying degrees and to RBCT at different levels of anaemia in preterm infants of different gestational and post-natal ages is needed before we can conclusively guide the optimal timing and trigger thresholds for RBCT in preterm infants.

Albumin synthesis in very low birth weight infants is enhanced by early parenteral lipid and high-dose amino acid administration

BACKGROUND & AIMS

Albumin is one of the most important plasma proteins and plays a key role in many physiologic processes, such as preserving colloid osmotic pressure, scavenging radicals, and binding and transporting bilirubin, hormones, and drugs. However, albumin concentrations are often low in preterm infants during the first days of life. We hypothesized that early parenteral lipid and high-dose amino acid (AA) administration to very low birth weight (VLBW) infants from birth onwards increases hepatic albumin synthesis rates.

METHODS

Inborn VLBW infants were randomized to receive from birth onwards either 2.4 g amino acids/(kg(·)d) (control group), 2.4 g amino acids/(kg(·)d) plus 2 g lipids/(kg(·)d) (AA + lipid group), or 3.6 g amino acids/(kg(·)d) plus 2 g lipids/(kg(·)d) (high AA + lipid group). On postnatal day 2, infants received a primed continuous infusion of [U-(13)C6,(15)N]leucine. Mass spectrometry was used to determine the fractional and absolute albumin synthesis rates (FSR and ASR, respectively).

RESULTS

In total, 28 infants (median gestational age 27 weeks (IQR 25-28), median birth weight 810 g (IQR 679-998) were studied. The median FSR was 6.5%/d in the control group, 10.6%/d in the AA group, and 12.3%/d in the high AA + lipid group, while the median was 84 mg/(kg(·)d) in the control group, 138 mg/(kg(·)d) in the AA group, and 160 mg/(kg(·)d) in the high AA + lipid group.

CONCLUSION

A group of VLBW infants given parenteral nutrition containing lipids and high-dose amino acids showed a higher rate of albumin synthesis compared to infants receiving no lipids and standard amounts of amino acids during the first two days of life.

Measurement of posttransfusion red cell survival with the biotin label

The goal of this review is to summarize and critically assess information concerning the biotin method to label red blood cells (RBC) for use in studies of RBC and transfusion biology-information that will prove useful to a broad audience of clinicians and scientists. A review of RBC biology, with emphasis on RBC senescence and in vivo survival, is included, followed by an analysis of the advantages and disadvantages of biotin-labeled RBC (BioRBC) for measuring circulating RBC volume, posttransfusion RBC recovery, RBC life span, and RBC age-dependent properties. The advantages of BioRBC over (51)Cr RBC labeling, the current reference method, are discussed. Because the biotin method is straightforward and robust, including the ability to follow the entire life spans of multiple RBC populations concurrently in the same subject, BioRBC offers distinct advantages for studying RBC biology and physiology, particularly RBC survival. The method for biotin labeling, validation of the method, and application of BioRBCs to studies of sickle cell disease, diabetes, and anemia of prematurity are reviewed. Studies documenting the safe use of BioRBC are reviewed; unanswered questions requiring future studies, remaining concerns, and regulatory barriers to broader application of BioRBC including adoption as a new reference method are also presented.

Changes in circulating red cell volume during the first 6 weeks of life in very-low-birth-weight infants

BACKGROUND

Little is known about the change in circulating red cell volume (RCV) of very-low-birth-weight (VLBW) infants during the first weeks of life.

METHODS

RCV was measured during the first 5 d in 35 VLBW infants using chromium-51 labeling of the infants' red blood cells (RBCs). RCV was measured again at 6 wk of age in 12 infants, and the volumes of RBCs lost by phlebotomy and those gained by transfusion were recorded between the RCV measurements. In six infants, the volume of waste blood on materials contaminated with blood during phlebotomy, which would usually be discarded, was measured by radioactive counting.

RESULTS

The mean RCV in the first several days of life was 39.6 ml (35.7 ml/kg; range: 20.1-58.7 ml/kg). Of the 12 infants whose RCV was measured twice, all but one had a decrease in absolute RCV. The mean RCV initially and at 6 wk were 37.3 and 26.6 ml, respectively. The mean volume of RBCs lost through phlebotomy was 29.2 ml, and the mean volume of RBCs given by transfusion was 34.5 ml.

CONCLUSION

During the first 6 wk of life, when the anemia of prematurity is evolving, the RCV falls despite complete replacement of RBCs lost by diagnostic phlebotomy with transfused RBCs.

Comparison of multiple red cell volume methods performed concurrently in premature infants following allogeneic transfusion

BACKGROUND

Study of the pathophysiology and treatment of anemia of prematurity is facilitated by direct measurement of red cell volume (RCV) utilizing microliter quantities of blood samples. Our objective was to compare concurrent measurements of multiple direct RCV methods in infants.

METHODS

Eighteen preterm infants receiving clinically indicated transfusions had concurrent flow cytometric determinations of RCV and 24-h red blood cell (RBC) recovery based on donor-recipient differences of biotin-labeled RBCs (BioRBCs), Kidd antigen mismatched RBCs, and fetal hemoglobin-positive (HbF(+)) RBCs. High-performance liquid chromatography (HPLC) was also used for measuring HbF and adult hemoglobin protein concentrations for the determination of RCV.

RESULTS

Concurrent RCV measurements using BioRBCs (18 and 54 µg/ml), Kidd antigen, and HbF flow cytometry were not statistically different compared with RCVs measured using the reference BioRBC density (6 µg/ml). By contrast, the HbF-HPLC method overestimated RCV by 45% compared with the reference method. All the methods demonstrated 100% 24-h posttransfusion RBC recovery (PTR24).

CONCLUSION

Because BioRBC, Kidd antigen, and fetal hemoglobin (HbF) flow cytometry are safe and accurate methods requiring <10 µl of patient blood for determining RCV and PTR24 in preterm infants, they can be useful in clinical and research studies of anemia and other conditions.

Nonpharmacological, blood conservation techniques for preventing neonatal anemia--effective and promising strategies for reducing transfusion

The development of anemia after birth in very premature, critically ill newborn infants is a universal well-described phenomenon. Although preventing anemia in this population, along with efforts to establish optimal red blood cell (RBC) transfusion and pharmacologic therapy continue to be actively investigated, the present review focuses exclusively on nonpharmacological approaches to the prevention and treatment of neonatal anemia. We begin with an overview of topics relevant to nonpharmacological techniques. These topics include neonatal and fetoplacental hemoglobin levels and blood volumes, clinical and laboratory practices applied in critically ill neonates, and current RBC transfusion practice guidelines. This is followed by a discussion of the most effective and promising nonpharmacological blood conservation strategies and techniques. Fortunately, many of these techniques are feasible in most neonatal intensive care units. When applied together, these techniques are more effective than existing pharmacotherapies in significantly decreasing neonatal RBC transfusions. They include increasing hemoglobin endowment and circulating blood volume at birth; removing less blood for laboratory testing; and optimizing nutrition.

Accelerated removal of antibody-coated red blood cells from the circulation is accurately tracked by a biotin label

BACKGROUND

Safe, accurate methods to reliably measure circulating red blood cell (RBC) kinetics are critical tools to investigate pathophysiology and therapy of anemia, including hemolytic anemias. This study documents the ability of a method using biotin-labeled RBCs (BioRBCs) to measure RBC survival (RCS) shortened by coating with a highly purified monomeric immunoglobulin G antibody to D antigen.

STUDY DESIGN AND METHODS

Autologous RBCs from 10 healthy D+ subjects were labeled with either biotin or (51) Cr (reference method), coated (opsonized) either lightly (n = 4) or heavily (n = 6) with anti-D, and transfused. RCS was determined for BioRBCs and for (51) Cr independently as assessed by three variables: 1) posttransfusion recovery at 24 hours (PTR(24) ) for short-term RCS; 2) time to 50% decrease of the label (T(50) ), and 3) mean potential life span (MPL) for long-term RCS.

RESULTS

BioRBCs tracked both normal and shortened RCS accurately relative to (51) Cr. For lightly coated RBCs, mean PTR(24) , T(50) , and MPL results were not different between BioRBCs and (51) Cr. For heavily coated RBCs, both short-term and long-term RCS were shortened by approximately 17 and 50%, respectively. Mean PTR(24) by BioRBCs (84 ± 18%) was not different from (51) Cr (81 ± 10%); mean T(50) by BioRBCs (23 ± 17 days) was not different from (51) Cr (22 ± 18 days).

CONCLUSION

RCS shortened by coating with anti-D can be accurately measured by BioRBCs. We speculate that BioRBCs will be useful for studying RCS in conditions involving accelerated removal of RBCs including allo- and autoimmune hemolytic anemias.

Red blood cell (RBC) survival determined in humans using RBCs labeled at multiple biotin densities

BACKGROUND

Safe, accurate methods permitting simultaneous and/or repeated measurement of red blood cell (RBC) survival (RCS) are important to investigate pathophysiology and therapy of anemia. Methods using chromium 51 ((51) Cr)-labeled RBCs are unacceptable for infants, children, and pregnant women. We report RCS measured in vivo using RBCs labeled with several densities of biotin (BioRBCs).

STUDY DESIGN AND METHODS

Aliquots of autologous RBCs from eight healthy adult subjects were labeled separately at four discrete biotin densities, mixed, and infused. The proportion of each population of BioRBCs circulating was determined serially by flow cytometry over 20 weeks. For each population, RCS was assessed by the following: 1) posttransfusion BioRBC recovery at 24 hours (PTR(24) ); 2) time to decrease to 50% of the enrichment at 24 hours (T(50) ); and 3) mean potential lifespan (MPL).

RESULTS

Among the four BioRBC densities, no significant differences in PTR(24) were observed. T(50) and MPL were similar for the two lowest BioRBC densities. In contrast, the two highest BioRBC densities demonstrated progressively decreased T(50) and MPL.

CONCLUSIONS

RBCs labeled at four biotin densities can be used to independently and accurately measure PTR(24 ) and two lowest biotin densities can accurately quantitate long-term RCS. This method provides a tool for investigating anemia in infants, fetuses, and pregnant women with the following advantages over the standard (51) Cr method: 1) study subjects are not exposed to radiation; 2) small blood volumes (e.g., 20 µL) are required; and 3) multiple independent RCS measurements can be made simultaneously in the same individual.

Measuring circulating blood volume in newborn infants using pulse dye densitometry and indocyanine green

BACKGROUND

Circulating blood volume (BV) is an important, but often unconsidered, variable in newborn infants undergoing intensive care. The data on validation and repeatability of BV measurement are limited.

AIM

To validate and test the repeatability of measuring BV in newborn infants using indocyanine green (ICG) and pulse dye densitometry (PDD).

METHODS

Validation--Paired measurements of BV were made using the fetal hemoglobin (HbF) dilution and the PDD method. Repeatability--The BV was measured twice at an interval of 30-40 min in a second group of infants.

RESULTS

Validation--Data from three of 13 infants studied were excluded because of probe dislodgement or ICG injection error. The median (range) birth weight of the 10 infants whose data were analyzed was 1032 g (740-2384 g) and seven (70%) were receiving either mechanical ventilation or nasal CPAP. The median BV measured by HbF dilution was 66.2 ml x kg(-1) (43.7-81.0 ml x kg(-1)) and by the PDD method was 68.9 ml x kg(-1) (49.3-101.0 ml x kg(-1)). The mean difference was 5.92 ml x kg(-1) (SD 17.33 ml x kg(-1)). Repeatability--Twelve infants were studied and three excluded because of probe dislodgement/motion artifact or ICG injection error. The median weight of the nine infants whose data were analyzed was 1208 g (795-2600 g). The median (range) BV1 and BV2 were 70.5 ml x kg(-1) (53.1-160 ml x kg(-1)) and 87.5 ml x kg(-1) (38.0-248.0 ml x kg(-1)), respectively. Mean difference of the two BV estimates (BV1-BV2) was -24.6 ml x kg(-1) (SD 33.3 ml x kg(-1)) and coefficient of repeatability was 66.5 ml x kg(-1).

CONCLUSION

Pulse dye densitometry can be used to measure BV in the newborn infant at the cotside but the repeatability measurements suggest that its use is limited.

Early versus late cord clamping: effects on peripheral blood flow and cardiac function in term infants

BACKGROUND

In the debate on the best cord clamping time in newborn infants, we hypothesized that late cord clamping enables an increased volemia due to blood transfer to the newborn from the placenta.

AIM

To assess whether clamping time can affect limb perfusion and heart hemodynamics in a group of 22 healthy term newborn infants.

STUDY DESIGN

A case-control study.

SUBJECTS

Eleven early-clamped (at 30 s) vaginally-delivered newborn infants were compared with eleven late-clamped (at 4 min) newborns.

OUTCOME MEASURES

The two groups were studied using near-infrared spectroscopy and M-mode echocardiography.

RESULTS

Late cord clamping coincided with a higher hematocrit (median 62% versus 54%) and hemoglobin concentration (median 17.2 versus 15 g/dL), whilst there were no changes in bilirubin level. Echocardiography showed a larger end-diastolic left ventricle diameter (1.7 cm median value versus 1.5) coupled with unvaried shortening and ejection fraction values. There were no changes in calf blood flow, oxygen delivery, oxygen consumption or fractional oxygen extraction calculated from the NIRS measurements, or in foot perfusion index.

CONCLUSIONS

Our results demonstrated that late cord clamping coincides with an increased placental transfusion, expressed by higher hematocrit and hemoglobin values, and larger left ventricle diameter at the end of the diastole, with no changes in peripheral perfusion or oxygen metabolism.

Albumin synthesis in premature neonates is stimulated by parenterally administered amino acids during the first days of life

BACKGROUND

We recently showed that parenteral administration of amino acids to premature infants immediately after birth is safe and results in a positive nitrogen balance and increased whole-body protein synthesis. However, we did not determine organ-specific effects; albumin, produced by the liver, is an important protein, but its concentration is often low in premature neonates during the first few days after birth.

OBJECTIVE

The objective of the study was to test the hypothesis that the fractional and absolute albumin synthesis rates would increase with the administration of amino acids after birth, even at low nonprotein energy intake.

DESIGN

Premature infants (<1500 g birth weight), who were on ventilation, received from birth onward either glucose only (control group, n = 7) or glucose and 2.4 g amino acid kg(-1) d(-1) (intervention group, n = 8). On postnatal day 2, all infants received a primed continuous infusion of [1-(13)C]leucine, and mass spectrometry techniques were used to determine the incorporation of the leucine into albumin. Results are expressed as medians and 25th and 75th percentiles.

RESULTS

Albumin fractional synthesis rates in the intervention group were significantly higher than those in the control group [22.9% (17.6-28.0%)/d and 12.6% (11.0-19.4%)/d, respectively; P = 0.029]. Likewise, the albumin absolute synthesis rates in the intervention group were significantly higher than those in the control group [228 (187-289) mg kg(-1) d(-1) and 168 (118-203) mg kg(-1) d(-1), respectively; P = 0.030].

CONCLUSION

Amino acid administration increases albumin synthesis rates in premature neonates even at a low energy intake.

Treating hypotension in the preterm infant: when and with what: a critical and systematic review

A very large proportion of extremely preterm infants receive treatments for hypotension. There are, however, marked variations in indications for treatment, and in the interventions used, between neonatal intensive care units and between neonatologists.

METHODS

We performed systematic reviews of the literature in order to determine which preterm infants may benefit from treatment with interventions to elevate blood pressure (BP), and which interventions improve clinically important outcomes.

RESULTS

Our review was not able to define a threshold BP that was significantly predictive of a poor outcome, nor whether any interventions for hypotensive infants improved outcomes, nor which interventions were more likely to be beneficial.

CONCLUSIONS

There is a distinct lack of prospective research of this issue, which prevents good clinical care. It is possible that a simple BP threshold that indicates the need for therapy does not exist, and other factors, such as the clinical status or systemic blood flow measurements, may be much more informative. Such a paradigm shift will also require careful prospective study.

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.

Prospective evaluation of postnatal steroid administration: a 1-year experience from the California Perinatal Quality Care Collaborative

OBJECTIVE

Postnatal steroids (PNSs) are used frequently to prevent or treat chronic lung disease (CLD) in the very low birth weight (VLBW) infant, and their use continues despite concerns regarding an increased incidence of longer-term neurodevelopmental abnormalities in such infants. More recently, there has been a suggestion that corticosteroids may be a useful alternative therapy for hypotension in VLBW infants, but there have been no prospective reports of such use for a current cohort of VLBW infants.

METHODS

The California Perinatal Quality Care Collaborative (CPQCC) requested members to supplement their routine Vermont Oxford Network data collection with additional information on any VLBW infant treated during their hospital course with PNS, for any indication. The indication, actual agent used, total initial daily dose, age at treatment, type of respiratory support, mean airway pressure, fraction of inspired oxygen, and duration of first dosing were recorded.

RESULTS

From April 2002 to March 2003 in California, 22 of the 62 CPQCC hospitals reported supplemental data, if applicable, from a cohort of 1401 VLBW infants (expanded data group [EDG]), representing 33.2% of the VLBW infants registered with the CPQCC during the 12-month period. PNSs for CLD were administered to 8.2% of all VLBW infants in 2003, 8.6% of infants in the 42 hospitals that did not submit supplemental data (routine data-set group, compared with 7.6% in EDG hospitals). Of the 1401 VLBW infants in the EDG, 19.3% received PNSs; 3.6% received PNSs for only CLD, 11.8% for only non-CLD indications, and 4.0% for both indications. At all birth weight categories, non-CLD use was significantly greater than CLD use. The most common non-CLD indication was hypotension, followed by extubation stridor, for which 36 (16.3%) infants were treated. For hypotension, medications used were hydrocortisone followed by dexamethasone. Infants treated with PNSs exclusively for hypotension had a significantly higher incidence of intraventricular hemorrhage, periventricular leukomalacia, and death when compared with infants treated only for CLD or those who did not receive PNSs.

CONCLUSIONS

The common early use of hydrocortisone for hypotension and the high morbidity and mortality in children receiving such treatment has not been recognized previously and prospective trials evaluating the short- and long-term risk/benefit of such treatment are urgently required.

A new formula for blood transfusion volume in the critically ill

BACKGROUND

Published formulae, frequently used to predict the volume of transfused red cells required to achieve a desired rise in haemoglobin (Hb) or haematocrit (Hct), do not appear to have been validated in clinical practice.

AIMS

To examine the relation between transfusion volume and the resulting rise in Hb and Hct in critically ill children.

METHODS

Phase 1: Sample of 50% of children admitted during 1997; 237 of these 495 patients received at least one packed red cell transfusion; 82 children were transfused without confounding factors that could influence the Hb/Hct response to transfusion and were analysed further. Actual rise in Hb concentration or haematocrit was compared to that expected from use of existing formulae. A new formula was developed. Phase 2: In 50 children receiving a packed red cell transfusion during 2001, actual rise in Hb concentration was compared to expected rise in Hb with use of the new formula.

RESULTS

Phase 1: Existing formulae performed poorly; median ratio of actual/predicted rise in Hb or Hct ranged from 0.61 to 0.85. Using the regression coefficients new formulae were developed for both Hb and Hct. These formulae were applicable across all age and diagnostic groups. Phase 2: Median ratio of actual/predicted rise in Hb improved to 0.95 with use of the new formula.

CONCLUSIONS

Existing formulae underestimate the volume of packed red cells required to achieve a target Hb or Hct. Adoption of the new formulae could reduce the number of transfusion episodes in PICU, cutting costs and reducing risk.