Tubular Reabsorption of Glucose During Pregnancy

Continuous infusion of isoproterenol or electric stimulation of left stellate ganglion in atropinized dogs changed the cardiac response to high aortic blood pressure. In thoracotomized dogs, cardiac output rose when ventricular systolic blood pressure was increased from 100 to more than 200 mm Hg by constriction of the descending aorta. Myocardial dimensions as measured by ultrasonic distance gauges implanted one cm apart in the left myocardium (myocardial distance) showed only slight changes. In control experiments at normal inotropic levels, or after blocking β-receptors by propranolol, the effect of increasing aortic pressure was maintenance or reduction of cardiac output. Myocardial distances were increased with reductions in amplitude of the beat-to-beat oscillations. In unanesthetized dogs, angiotensin infusion reduced cardiac output and increased myocardial dimensions under control conditions. During infusion of isoproterenol the response to angiotensin at similar increments of blood pressure was an increase in cardiac output and nearly no increase in myocardial dimensions. These studies show that the cardiac response to increased blood pressure is dependent on the level of inotropy.     

Mechanisms of Abnormal Glucose Metabolism During the Treatment of Acute Severe Asthma

Twenty-five patients with acute severe asthma were treated withoxygen, corticosteroids and either salbutamol or aminophyllineby intravenous infusion. Blood glucose, plasma insulin and glucagonwere measured during the first 24 hours of treatment. Salbutamoland aminophylline rapidly caused hyperglycaemia, accompaniedby a rise in insulin and a fall in plasma glucagon. At firstthe increase in plasma insulin was insufficient to restore normoglycaemia,but by 24 hours homeostasis was restored. The early submaximalinsulin response was attributed to the fasting caused by breathlessness.There was no evidence of an increase in hormone secretion causedby direct ß₂-adrenergic stimulation of the pancreaticislets. The effect of corticosteroids on blood glucose overthe period of study was considerably less than the contributionof either salbutamol, or aminophylline.     

Early Microvascular Recruitment Modulates Subsequent Insulin-Mediated Skeletal Muscle Glucose Metabolism During Lipid Infusion

OBJECTIVE

To test whether early, insulin-mediated microvascular recruitment in skeletal muscle predicts steady-state glucose metabolism in the setting of physiological elevation of free fatty acid concentrations.

RESEARCH DESIGN AND METHODS

We measured insulin’s microvascular and metabolic effects in 14 healthy young adults during a 2-h euglycemic insulin clamp. Plasma free fatty acid concentrations were raised (Intralipid and heparin infusion) for 3 h before the clamp and maintained at postprandial concentrations during the clamp. Microvascular blood volume (MBV) was measured by contrast-enhanced ultrasound (CEU) continuously from baseline through the first 30 min of the insulin clamp. Muscle glucose and insulin uptake were measured by the forearm balance method.

RESULTS

The glucose infusion rate (GIR) necessary to maintain euglycemia during the clamp varied by fivefold across subjects (2.5–12.5 mg/min/kg). The early MBV responses to insulin, as indicated by CEU video intensity, ranged widely, from a 39% decline to a 69% increase. During the clamp, steady state forearm muscle glucose uptake and GIR each correlated significantly with the change in forearm MBV (P < 0.01). To explore the basis for the wide range of vascular and metabolic insulin sensitivity observed, we also measured Vo_2max in a subset of eight subjects. Fitness (Vo_2max) correlated significantly with the GIR, the forearm glucose uptake, and the percentage change in MBV during the insulin clamp (P < 0.05 for each).

CONCLUSIONS

Early microvascular responses to insulin strongly associate with steady state skeletal muscle insulin-mediated glucose uptake. Physical fitness predicts both metabolic and vascular insulin responsiveness.Insulin recruits underperfused capillaries to increase skeletal muscle microvascular blood volume (MBV), as measured by contrast-enhanced ultrasound (CEU), within 20 min in both rats (1) and humans (2,3). This effect occurs with physiological insulin concentrations (2,4) and precedes both changes in total limb blood flow (1,5,6) and insulin’s metabolic action (1). In rodents, microvascular recruitment enhances the rate at which insulin is delivered to muscle interstitium (7), thereby facilitating insulin’s metabolic action, and exercise training has been shown to enhance insulin-induced microvascular recruitment and muscle glucose disposal in rodents (8).Raising plasma concentrations of free fatty acids (FFAs) induces insulin resistance within 2–4 h, can induce inflammation in muscle (9) and in circulating leukocytes (10), and produces endothelial dysfunction (10,11). Clinical studies have shown a marked impairment in insulin’s ability to recruit both muscle and skin microvasculature in chronically insulin-resistant obese subjects (12–14). FFA-induced insulin resistance impairs insulin-mediated microvascular recruitment in skin with elevation of FFA to physiological levels (∼1 mmol/L) (15) and in muscle microvasculature with higher FFA levels ∼3 mmol/L (16).Both acute exercise and training can affect the metabolic response to raising plasma FFA. Raising plasma FFA acutely through lipid and heparin infusion has less effect on insulin sensitivity in individuals who exercised intensively the preceding day (17). Exercise training also prevents FFA-induced hepatic and peripheral insulin resistance (18). It is not known whether training affects insulin-induced microvascular recruitment or the ability of FFA to inhibit recruitment in humans.Recently, we reported that human skeletal muscle insulin uptake (product of forearm blood flow and arteriovenous concentration) could be quantified and that it occurred through a saturable transport process at physiological concentrations of insulin (2). Whether FFA elevation would, by blocking insulin-induced increases in MBV, also limit muscle insulin uptake is not known.In this study, CEU was used to measure muscle microvascular perfusion and paired arterial and venous sampling to measure muscle insulin and glucose uptake in response to a physiologic insulin infusion in 14 healthy volunteers whose plasma FFA levels were maintained in a range encountered in human insulin-resistant states (∼1.0 mmol/L). To examine whether fitness was predictive of these responses, a subset of 8 volunteers underwent maximal exercise testing to quantify the relationship between Vo_2max and muscle metabolic and microvascular insulin sensitivity.     

高血压病患者OGTT1小时切点血糖在筛查糖代谢异常中的意义

目的探讨高血压病患者葡萄糖耐量试验（OGTT）1小时切点血糖（1hPG）筛查糖代谢异常的可能切点数值和意义。方法纳入2009年1月至2011年6月本院内分泌门诊就诊的高血压病患者112例,行75 g OGTT试验,采用受试者工作特征曲线（ROC曲线）确定糖代谢异常时OGTT 1hPG对应的最佳切点数值,以此切点的数值分两组人群比较两组间的体质量指数（BMI）,空腹血糖（FPG）,三酰甘油（TG）,胆固醇（CHO）,高、低密度脂蛋白胆固醇（HDL‐C、LDH‐C）,血尿酸（UA）,胰岛素抵抗指数（HOMA‐IR）、胰岛β细胞功能（HOMA‐β）水平。结果①研究中新诊断DM为36例（32．1％）,糖调节受损（IGR）46例（41．1％）,糖耐量正常（NGT）30例（26．8％）。②ROC曲线显示以OGTT 1hPG≥10．1 mmol／L作为诊断糖代谢异常的切点,敏感性89％,特异性90％。③以10．1为切点分组后,1hPG≥10．1 mmol／L组的UA、FPG、HOMA‐IR指数高于＜10．1 mmol／L组（ P ＜0．05）,HOMA‐β指数低于＜10．1组（ P ＜0．05）,两组BMI、空腹真胰岛素（FTI）、TG、CHO、LDL‐C、HDL‐C、比较差异无统计学意义。结论高血压病患者中,当OGTT 1hPG≥10．1 mmol／L ,已出现明显的糖代谢紊乱,1hPG可反应胰岛素抵抗程度及胰岛β细胞分泌功能。     

Cation Metabolism During Propofol Sedation With and Without EDTA in Patients With Impaired Renal Function

Objective: To compare the effects of propofol with and without disodium edetate (EDTA) on cation metabolism in intensive care unit (ICU) patients with renal insufficiency who received propofol or propofol plus EDTA (propofol EDTA) for sedation and mechanical ventilation. Design: Double-blind, randomised, multicentre study. Setting: Medical and surgical ICUs from 5 hospitals. Patients: Thirty-nine ICU patients with acute and chronic renal impairment expected to require at least 24 hours of continuous sedation and respiratory failure necessitating mechanical ventilation. Interventions: Propofol or propofol EDTA administered for sedation by continuous intravenous infusion. Measurements and Results: The depth of sedation, as measured by the Modified Ramsay Sedation Scale, was similar in the 2 groups, when adjusted for dosing differences. The amount of propofol required to maintain adequate sedation was decreased in both groups compared to propofol requirements in ICU patients with normal renal function. EDTA levels were elevated at baseline in both groups. In the propofol EDTA group, the EDTA levels increased further by 20 % but decreased to below baseline EDTA levels at 48 hours after sedation. In the propofol group, EDTA levels decreased during sedation and remained below baseline levels at 48 hours after sedation. Patients in both groups were hypocalcaemic and hyperphosphataemic at baseline with low levels of 1,25-dihydroxyvitamin D and elevated parathyroid hormone (PTH) levels. Other than a slight difference in ionised serum calcium levels at 4 h after the start of sedation, there were no significant differences observed in serum calcium levels between the two groups. There were no significant differences in 1,25-dihydroxyvitamin D or PTH levels over time between the two groups. There was no significant effect on renal function in either group. Conclusions: The results of this study suggest that adding EDTA to propofol does not adversely affect cation homeostasis or renal function when used for sedation of ICU patients with renal insufficiency. Although EDTA levels increased over time from baseline levels in patients with renal insufficiency who receive propofol EDTA, this increase does not appear to be clinically significant, and EDTA levels return to below baseline levels within 48 hours of discontinuing the propofol EDTA infusion. The efficacy of propofol with and without EDTA also appears comparable in these patients.     

Cation Metabolism During Propofol Sedation With and Without EDTA in Patients With Impaired Renal Function

Objective: To compare the effects of propofol with and without disodium edetate (EDTA) on cation metabolism in intensive care unit (ICU) patients with renal insufficiency who received propofol or propofol plus EDTA (propofol EDTA) for sedation and mechanical ventilation. Design: Double-blind, randomised, multicentre study. Setting: Medical and surgical ICUs from 5 hospitals. Patients: Thirty-nine ICU patients with acute and chronic renal impairment expected to require at least 24 hours of continuous sedation and respiratory failure necessitating mechanical ventilation. Interventions: Propofol or propofol EDTA administered for sedation by continuous intravenous infusion. Measurements and Results: The depth of sedation, as measured by the Modified Ramsay Sedation Scale, was similar in the 2 groups, when adjusted for dosing differences. The amount of propofol required to maintain adequate sedation was decreased in both groups compared to propofol requirements in ICU patients with normal renal function. EDTA levels were elevated at baseline in both groups. In the propofol EDTA group, the EDTA levels increased further by 20 % but decreased to below baseline EDTA levels at 48 hours after sedation. In the propofol group, EDTA levels decreased during sedation and remained below baseline levels at 48 hours after sedation. Patients in both groups were hypocalcaemic and hyperphosphataemic at baseline with low levels of 1,25-dihydroxyvitamin D and elevated parathyroid hormone (PTH) levels. Other than a slight difference in ionised serum calcium levels at 4 h after the start of sedation, there were no significant differences observed in serum calcium levels between the two groups. There were no significant differences in 1,25-dihydroxyvitamin D or PTH levels over time between the two groups. There was no significant effect on renal function in either group. Conclusions: The results of this study suggest that adding EDTA to propofol does not adversely affect cation homeostasis or renal function when used for sedation of ICU patients with renal insufficiency. Although EDTA levels increased over time from baseline levels in patients with renal insufficiency who receive propofol EDTA, this increase does not appear to be clinically significant, and EDTA levels return to below baseline levels within 48 hours of discontinuing the propofol EDTA infusion. The efficacy of propofol with and without EDTA also appears comparable in these patients.     

肥胖儿童瘦素受体基因变异对脂质代谢及脂肪分布的影响

目的探讨瘦素受体（leptin receptor,LEPR）基因第20外显子变异对脂质代谢的影响。方法用聚合酶链式反应-限制性片断长度多态性（PCR-RFLP）法及聚丙烯酰胺凝胶电泳法分析120例单纯型肥胖儿童及120例健康儿童的LEPR基因的第20外显子基因变异频率,并测定血清中甘油三脂（TG）、总胆固醇（TC）、高密度脂蛋白（HDL）、低密度脂蛋白（LDL）,于相同条件下测身高、体重,按公式计算体重指数（BMI）、脂肪百分比（?t）。结果共检出3种第20外显子的基因型,其酶切片段分别为：A/A型：201bp,75bp;A/G型：201bp,173bp,75bp,28bp;G/G型：173bp,75bp,28bp。肥胖儿童较健康儿童LEPR基因第3057位G→A突变频率增高（P〈0.05）。纯合子A/A基因型的肥胖儿童其血清TG浓度、BMI、?t均明显高于纯合子G/G基因型者（P〈0.01）,而血清HDL水平则明显低于后者（P〈0.01）,杂合子A/G型肥胖儿童,除其血清TG浓度高于纯合子G/G基因型者外（P〈0.05）,余各项指标均与另外两种基因型无显著性差异。结论单纯型肥胖儿童瘦素受体基因第20外显子存在基因多态性的变化,且这种变化明显影响肥胖儿童的脂质代谢及体脂分布。纯合子A/A基因型个体应提早注意饮食结构,避免由此而继发的各种疾病。     

Improvement of Glucose Metabolism in Patients with Impaired Glucose Tolerance or Diabetes by Long-Term Administration of a Palatinose-Based Liquid Formula as a Part of Breakfast

A palatinose-based liquid formula (palatinose-formula), suppresses postprandial plasma glucose and insulin levels in healthy men. The objective of this study was to investigate the effects of long-term palatinose-formula ingestion on glucose metabolism in patients with impaired glucose tolerance (IGT) or type 2 diabetes. Two patients with IGT and 7 patients with type 2 diabetes participated in the palatinose-formula and dextrin-based liquid formula (dextrin-formula) loading test and long-term palatinose-formula administration study. After a 3-month control period, palatinose-formula (1046 kJ) was ingested daily by patients as a part of breakfast for 5 months. In the loading test, palatinose-formula suppressed postprandial plasma glucose and insulin levels and areas under the curve compared with those after dextrin-formula ingestion. In the long-term study, glycated hemoglobin levels (after 3 months and 5 months of treatment) and serum 8-hydroxydeoxyguanosine levels (after 5 months of treatment) were markedly decreased comparing with those at baseline. Intake of 1046 kJ palatinose-formula as a part of breakfast over a long-term period may be effective for improvement of glucose metabolism in patients with IGT or type 2 diabetes.     

Points to Remember In Prescribing Drugs During Pregnancy

Our knowledge of possible adverse drug effects on the fetus is quite limited. The doctor must act as the fetus' first line of defence. Mothers must be educated about the dangers of self-medication. Physicians must guard against drug administration to pregnant women unless the indications are clear and the expected benefit outweighs the possible risk to the fetus.     

Blood Flow and Glucose Metabolism in Stage IV Breast Cancer: Heterogeneity of Response During Chemotherapy

Objective  The purpose of the study was to compare early changes in blood flow (BF) and glucose metabolism (MR_glu) in metastatic breast cancer lesions of patients treated with chemotherapy. Methods  Eleven women with stage IV cancer and lesions in breast, lymph nodes, liver, and bone were scanned before treatment and after the first course of chemotherapy. BF, distribution volume of water (V _d), MR_glu/BF ratio, MR_glu and its corresponding rate constants K ₁ and k ₃ were compared per tumor lesion before and during therapy. Results  At baseline, mean BF and MR_glu varied among different tumor lesions, but mean V _d was comparable in all lesions. After one course of chemotherapy, mean MR_glu decreased in all lesions. Mean BF decreased in breast and node lesions and increased in bone lesions. V _d decreased in breast and nodes, but did not change in bone lesions. The MR_glu/BF ratio decreased in breast and bone lesions and increased in node lesions. In patients with multiple tumor lesions BF and MR_glu response could be very heterogeneous, even within similar types of metastases. BF and MR_glu increased in lesions of patients who experienced early disease progression or showed no response during clinical follow-up. Conclusion  BF and MR_glu changes separately give unique information on different aspects of tumor response to chemotherapy. Changes in BF and MR_glu parameters can be remarkably heterogeneous in patients with multiple lesions.     

Natural History of Insulin Sensitivity and Insulin Secretion in the Progression From Normal Glucose Tolerance to Impaired Fasting Glycemia and Impaired Glucose Tolerance: The Inter99 Study

OBJECTIVE—The aim of this study was to describe the natural history of insulin secretion and insulin sensitivity in the development of isolated impaired fasting glycemia (i-IFG), isolated impaired glucose tolerance (i-IGT), and combined IFG/IGT.RESEARCH DESIGN AND METHODS—Baseline and 5-year follow-up data from the Inter99 study were used. Individuals with normal glucose tolerance (NGT) at baseline and i-IFG, i-IGT, combined IFG/IGT, or NGT at the 5-year follow-up were examined with an oral glucose tolerance test (n = 3,145). Insulin sensitivity index (ISI), homeostasis model assessment of insulin sensitivity (HOMA-IS), early-phase insulin release (EPIR), and insulin secretion relative to insulin action (disposition index) were estimated.RESULTS—Five years before the pre-diabetes diagnoses (i-IFG, i-IGT, and IFG/IGT), ISI, HOMA-IS, EPIR, and disposition index were lower than in individuals who maintained NGT. During the 5-year follow-up, individuals developing i-IFG experienced a significant decline only in HOMA-IS, whereas individuals developing i-IGT experienced significant declines in ISI, EPIR, and disposition index. Individuals with IFG/IGT exhibited pronounced declines in ISI, HOMA-IS, EPIR, and disposition index during the 5-year follow-up.CONCLUSIONS—A stationary reduced insulin secretion followed by a decline in primarily hepatic insulin sensitivity characterizes the transition from NGT to i-IFG. In contrast, low whole-body insulin sensitivity with a secondary lack of β-cell compensation is associated with the development of i-IGT. Thereby, i-IFG and i-IGT appear to result from different underlying mechanisms, which may have implications for the prevention and treatment of the diabetes that succeeds them.During the past few years, it has been established that the pre-diabetic conditions of isolated impaired fasting glycemia (i-IFG), isolated impaired glucose tolerance (i-IGT), and combined fasting and postchallenge hyperglycemia (IFG/IGT) represent distinct pathways to diabetes. These pre-diabetic states are characterized by different degrees of insulin sensitivity, insulin secretion, and hepatic glucose output as well as secretion of glucagon and incretin hormones (1–8). Nevertheless, the primary abnormalities inherent in the different pre-diabetic conditions are still unknown.Randomized trials have shown beneficial effects of lifestyle intervention on diabetes risk in individuals with i-IGT and IFG/IGT (9,10), but whether lifestyle interventions have the same preventive effects in individuals with i-IFG is not known. Indeed, a more profound insight into the pathogenesis of the disease is needed to optimize prevention and treatment of type 2 diabetes. In particular, focus on the initial defects responsible for hyperglycemia in the fasting and postprandial states is essential for interrupting the progression from normal to abnormal glucose metabolism.Most previous studies have examined the pathophysiology of pre-diabetes in cross-sectional settings without knowing the time of onset of glycemic abnormalities. However, the observed abnormalities in pre-diabetes may be related to traits already apparent in the normoglycemic state. Prospective studies are therefore needed to clarify whether this is the case or whether the metabolic abnormalities associated with i-IFG, i-IGT, and IFG/IGT develop simultaneously with the increases in fasting and/or postchallenge plasma glucose levels.The aim of this study was to describe the natural history of insulin sensitivity and insulin secretion during the progression from normal glucose tolerance (NGT) to the pre-diabetic states of i-IFG, i-IGT, and combined IFG/IGT.     

Educating Nurses to Screen and Intervene for Intimate Partner Violence During Pregnancy

Intimate partner violence (IPV) is a problem affecting women and families across the nation, and it has been associated with adverse pregnancy and birth outcomes. Here we describe how our team implemented an evidence-based protocol for the screening of pregnant women for IPV and case management for those experiencing violence. This protocol was implemented on an antepartum triage unit where nurses were educated on IPV, methods for screening pregnant women, and a brief intervention. Education included an online module and a live session with role-playing exercises. Test scores indicated a significant increase in nurses’ knowledge after completion of the module, and the overall educational program was rated as excellent by program participants. As part of the project, the Abuse Assessment Screen and the Danger Assessment–5—two instruments with predictive validity—were incorporated into the electronic health record.     

妊娠合并输尿管结石致顽固性肾绞痛的腔内处理

【目的】探讨妊娠合并输尿管结石致顽固性肾绞痛安全有效的腔内处理方法。【方法】妊娠合并输尿管结石致肾绞痛经保守治疗无效患者14例,孕7~34周,平均27周。结石最大径5~12mm。输尿管上段结石8例,中段3例,下段3例。上段结石中6例单纯留置双J管,2例将结石推回肾盂后留置双J管。中下段结石中3例采用输尿管镜下气压弹道碎石术击碎结石,3例应用输尿管镜下双频激光碎石。【结果】12例术后肾绞痛消失;2例单纯放置双J管者仍有间断轻微肾绞痛,服用解痉药物可以缓解。8例未碎石在结石排出前每3个月更换双J管。14例孕妇均顺利生产,婴儿健康。【结论】妊娠合并输尿管结石致顽固性肾绞痛患者采用逆行输尿管插管或输尿管镜取石术安全有效。     

Inoculation Against Falls: Rapid Adaptation by Young and Older Adults to Slips During Daily Activities

Pai Y-C, Bhatt T, Wang E, Espy D, Pavol MJ. Inoculation against falls: rapid adaptation by young and older adults to slips during daily activities.

Objective

To determine whether aging diminishes one's ability to rapidly learn to resist falls on repeated-slip exposure across different activities of daily living.

Design

Quasi-experimental controlled trial.

Setting

Two university-based research laboratories.

Participants

Young (n=35) and older (n=38) adults underwent slips during walking. Young (n=60) and older (n=41) adults underwent slips during a sit-to-stand task. All (N=174) were healthy and community dwelling.

Intervention

Low-friction platforms induced unannounced blocks of 2 to 8 repeated slips interspersed with blocks of 3 to 5 nonslip trials during the designated task.

Main Outcome Measures

The incidence of falls and balance loss. Dynamic stability (based on center of mass position and velocity) and limb support (based on hip height) 300ms after slip onset.

Results

Under strictly controlled, identical low-friction conditions, all participants experienced balance loss, but older adults were over twice as likely as young to fall on the first, unannounced, novel slip in both tasks. Independent of age or task, participants adapted to avoid falls and balance loss, with most adaptation occurring in early trials. By the fifth slip, the incidence of falls and balance loss was less than 5% and 15%, respectively, regardless of age or task. Reductions in falls and balance loss for each task were accomplished through improved control of stability and limb support in both age groups. A rapidly reversible age- and task-dependent waning of motor learning occurred after a block of nonslip trials. Adaptation to walk slips reached a steady state in the second slip block regardless of age.

Conclusions

The ability to rapidly acquire fall-resisting skills on repeated-slip exposure remains largely intact at older ages and across functional activities. Thus, repeated-slip exposure might be broadly effective in inoculating older adults against falls.     

Comparing Psychological Adaptation to having a Disease Gene in Affected Individuals and Unaffected Carrier Parents

Health care professionals are in an ideal situation to help families inform their children about genetic conditions. In families where there is a child with a known genetic condition, parents make decisions about when and how to convey information to their children, however, little is known about how parents make these decisions. The purpose of this qualitative analysis was to examine parents' beliefs and strategies related to sharing information with their children. The sample consisted of 139 parents of children with sickle cell disease, phenylketonuria, cystic fibrosis, Marfan syndrome, neurofibromatosis, hemophilia, and von Willebrand disease. Audio recorded, semi-structured interviews were transcribed verbatim, processed, and coded using the ATLAS.ti software. Thematic analysis found: parents share information and develop specific strategies within a context of normalizing the child's life; parents' decisions to share information are based on a developmental framework; parental strategies for sharing information with children may differ when the child has a potentially life-limiting genetic condition. Findings emphasize the need to use a family developmental perspective when working with families of children with genetic conditions. These findings will provide new information about how families manage information and provide direction for care of families in which a child has a genetic condition.     

Current Evidence for the Use of Prophylactic Transfusion to Treat Sickle Cell Disease During Pregnancy

The role of prophylactic transfusion therapy for the treatment of sickle cell disease during pregnancy is unclear. An analysis of the existing literature shows a limited number of publications that address this issue and specifically compare clinical outcomes in this population based on a treatment strategy of prophylactic transfusion versus transfusion only for clinical indications (on-demand transfusion). The existing studies show a wide variation in study design and outcomes measured. The results of this analysis suggest that there are insufficient data to support a clinically significant difference in morbidity and mortality outcomes based on transfusion strategy. Additional prospective clinical studies need to be performed to adequately address the risks and benefits of prophylactic transfusion and guide clinical decision making.