Red Blood Cell Transfusions Are Not Associated With Incident Complications or Poor Outcomes in Patients With Intracerebral Hemorrhage

Abstract

Background

Anemia is associated with poor intracerebral hemorrhage (ICH) outcomes, yet the relationship of red blood cell (RBC) transfusions to ICH complications and functional outcomes remains unclear. We investigated the impact of RBC transfusion on hospital thromboembolic and infectious complications and outcomes in patients with ICH.

Methods and Results

Consecutive patients with spontaneous ICH enrolled in a single‐center, prospective cohort study from 2009 to 2018 were assessed. Primary analyses assessed relationships of RBC transfusions on incident thromboembolic and infectious complications occurring after the transfusion. Secondary analyses assessed relationships of RBC transfusions with mortality and poor discharge modified Rankin Scale score 4 to 6. Multivariable logistic regression models adjusted for baseline demographics and medical disease severity (Acute Physiology and Chronic Health Evaluation II), and ICH severity (ICH score).Of 587 patients with ICH analyzed, 88 (15%) received at least one RBC transfusion. Patients receiving RBC transfusions had worse medical and ICH severity. Though patients receiving RBC transfusions had more complications at any point during the hospitalization (64.8% versus 35.9%), we found no association between RBC transfusion and incident complications in our regression models (adjusted odds ratio [aOR], 0.71 [95% CI, 0.42–1.20]). After adjusting for disease severity and other relevant covariates, we found no significant association between RBC transfusion and mortality (aOR, 0.87 [95% CI, 0.45–1.66]) or poor discharge modified Rankin Scale score (aOR, 2.45 [95% CI, 0.80–7.61]).

Conclusions

In our cohort with ICH, RBC transfusions were expectedly given to patients with higher medical and ICH severity. Taking disease severity and timing of transfusions into account, RBC transfusion was not associated with incident hospital complications or poor clinical ICH outcomes.

Nonstandard Abbreviations and Acronyms

ICH

intracerebral hemorrhage

JEL

Intracranial Hemorrhage

Clinical Perspective.

What Is New?

• Among patients with intracerebral hemorrhage, red blood cell transfusions are administered to sicker patients who encounter infectious or thromboembolic complications more frequently. However, red blood cell transfusions are not associated with incident (posttransfusion) complications when accounting for transfusion timing.

• Similarly, red blood cell transfusions are not associated with worse intracerebral hemorrhage outcomes when adjusting for disease severity.

What Are the Clinical Implications?

• Future prospective studies will be needed to address the independent clinical risks and benefits of red blood cell transfusions on intracerebral hemorrhage outcomes.

Intracerebral hemorrhage (ICH) is associated with high morbidity and mortality. ¹ Poor outcomes after ICH are largely due to initial cerebral tissue injury from the hematoma itself, as well as secondary brain injury, which can be caused by direct or indirect impairment of adequate cerebral tissue oxygen delivery. Low hemoglobin concentrations have consistently been associated with poor ICH outcomes. ² , ³ , ⁴ It is currently posited that low hemoglobin's relationship with poor outcomes is driven by impaired cerebral oxygen delivery causing secondary brain injury, as well as the association of low hemoglobin with hematoma expansion. ⁴ , ⁵ , ⁶

It remains unknown whether red blood cell (RBC) transfusions can be used as a treatment to modify hemoglobin concentrations to improve ICH outcomes. Liberal RBC transfusion paradigms are currently being explored in prospective randomized clinical treatment trials for patients with subarachnoid hemorrhage and traumatic brain injury. ⁷ , ⁸ , ⁹ But no such studies have yet been proposed for patients with ICH, as it is currently uncertain how RBC transfusions affect ICH outcomes ¹⁰ , ¹¹ and whether these transfusions carry inherent risks in this vulnerable patient group. There are reported relationships of RBC transfusions with thromboembolic and infectious complications, as well as poor outcomes in both general hospitalized patients and patients with brain injury without ICH. ¹² , ¹³ , ¹⁴ , ¹⁵ , ¹⁶ , ¹⁷ However, lack of detailed data on timing of RBC transfusion exposure and subsequent complications in these studies have limited an understanding of whether RBC transfusions themselves associate with these downstream complications. Additionally, it is unclear whether the associations of RBC transfusions with these complications are similarly relevant in patients with ICH specifically.

Given that thromboembolic and infectious complications are known to be associated with worse ICH outcomes, ¹⁸ , ¹⁹ , ²⁰ further work is necessary to characterize whether RBC transfusions potentially confer downstream complication risks in patients with ICH to best assess safety of potential future RBC transfusion approaches. Subsequently, we sought to investigate the relationship of RBC transfusion with incident thromboembolic and infectious complications and clinical outcomes in patients hospitalized with ICH. We hypothesized that after accounting for medical and ICH severity, RBC transfusion would not be associated with higher incident complications or worse clinical outcomes.

METHODS

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Study Design and Sample

Consecutive patients with spontaneous ICH were admitted and prospectively enrolled in an observational cohort study. Patients enrolled between 2009 and 2018 were included. Patients <18 years old or with ICH due to hemorrhagic metastasis or ischemic stroke with hemorrhagic conversion were not enrolled. Additionally, patients with ICH due to vascular malformation or aneurysm were excluded from analysis. Patients were managed according to American Heart Association guidelines, ²¹ with ICH treatment protocols described previously. ⁴ Baseline demographics, medical disease severity (via Acute Physiology and Chronic Health Evaluation II score), ²² radiographic ICH characteristics, ICH severity (via ICH score ²³ ), admission laboratory values, interventions (including RBC transfusions), hospital complications, and outcomes were prospectively collected as previously described. ⁴ This study was approved by our institutional review board, and consent was provided by the patient or designated surrogate.

RBC Transfusion

RBC transfusion was defined as the primary exposure variable. Date and time of RBC transfusion administration were a prospectively recorded data element confirmed via our institution's blood bank database. RBC transfusion was administered per the clinician's discretion but generally followed societal and our institution's guidelines, which recommend RBC transfusion for hemoglobin <7 g/dL or hemoglobin <8 g/dL with history or risk factors for cardiovascular disease, symptomatic anemia, and >15% blood volume loss. ²⁴

Thromboembolic, Infectious Complications, and Clinical Outcomes

Composite thromboembolic or infectious complications diagnosed during the ICH hospitalization were assessed as our primary outcome. Individual thromboembolic and infectious complications were separately explored. These complication events were recorded and adjudicated prospectively by a multidisciplinary clinical and research team and defined as per previously described criteria. ²⁵ , ²⁶ , ²⁷ , ²⁸ , ²⁹ , ³⁰ Thromboembolic events included myocardial infarction, deep vein thrombosis, and pulmonary embolism. Infections included pneumonia, bacteremia, and urinary tract infection. Diagnosis of myocardial infarction was made clinically in the setting of elevated troponin with supportive evidence of myocardial injury in the form of acute coronary symptoms or ischemic electrocardiography changes. Diagnosis of deep vein thrombosis required clinical suspicion and a newly identified thrombus in a deep vein of an upper or lower extremity by Doppler ultrasonography. Pulmonary embolism diagnosis required clinical suspicion and presence of new pulmonary artery thrombus on computerized tomography angiography. Pneumonia was diagnosed clinically in the presence of at least 2 of the following criteria: fever, leukocytosis, increased pulmonary secretions, increased oxygen requirement, focal consolidation on chest radiograph, and positive respiratory culture. A diagnosis of bacteremia required clinical suspicion for systemic infection and culture positivity from sterile blood cultures. Urinary tract infection diagnosis required clinical suspicion and an inflammatory urinalysis or growth of pathogen in urine culture when available. For patients who received at least 1 RBC transfusion, complications occurring at least 1 day after the administration of the first RBC unit were denoted as incident complications.

Secondary clinical outcomes assessed were hospital mortality and poor discharge neurological outcomes (modified Rankin Scale score 4–6).

Statistical Analysis

Intergroup differences between patients who were RBC transfused and not RBC transfused were determined by applying analysis of variance for normally distributed continuous variables and Mann–Whitney U test for continuous variables not normally distributed. For categorical variables, Fisher's exact test and chi‐square test were used to evaluate for differences between groups. Separate models assessed independent relationships of RBC transfusion on aggregate complications (occurring at any time during hospitalization) versus incident complications (occurring after the first RBC transfusion). Relationships between RBC transfusion and composite incident complications were assessed using multivariable logistic regression models adjusting for sex, race, medical disease severity (via Acute Physiology and Chronic Health Evaluation II score), ICH severity (via ICH score), and preceding antithrombotic medication use. These covariates were chosen a priori because these factors have previously been identified to be associated with poor ICH outcomes and used in prior literature to adjust for incident complication outcomes. ¹⁴ , ²³ , ³¹ , ³² , ³³ , ³⁴ Additional analyses were performed to explore the relationship of RBC transfusion on specific subtypes of thromboembolic and infectious complications. In our clinical outcome analyses, we performed logistic regression to evaluate relationships of RBC transfusion on clinical outcomes after adjusting for similar covariates. Sensitivity analyses adjusting for number of RBC transfusions administered, ventriculostomy, surgical intervention, and do‐not‐resuscitate/limitations of care were also performed to assess for changes in the relationships of RBC transfusion with incident complications and outcomes. Statistical significance was set at P<0.05, and all analyses were performed using SPSS version 28 (IBM).

RESULTS

In our overall cohort with ICH, the mean age was 65.5, 44.8% of patients were female, and the median hematoma volume was 14.8 mL (interquartile range 4.1–37.0 mL). Of 587 patients with ICH included for analyses, 15% (n=88) received at least 1 RBC transfusion. Among patients receiving an RBC transfusion, the median time to first RBC transfusion was 3 days after admission. Multiple RBC transfusions were given in 76% of patients receiving RBC transfusions with the median number of RBC units received being 3 (interquartile range 1–6). We did not identify any intergroup differences in baseline demographics between patients with ICH receiving and not receiving RBC transfusions. However, patients receiving RBC transfusions were more likely to have preceding anticoagulant medication use, worse ICH severity, worse medical disease severity, and longer length of stay (see Table 1, ³⁵ ).

Table 1.

Intergroup Baseline Characteristics

	RBC transfusion N=88	No RBC transfusion N=499	P value
Demographics: mean (SD) or N (%)
Age, y	64.3 (17.9)	65.7 (15.4)	0.414
Female sex	40 (45.5%)	216 (43.2%)	0.816
Race or ethnicity			0.094
White	24 (27.3%)	134 (26.9%)
Black	28 (31.8%)	120 (24.0%)
Asian	4 (4.5%)	25 (5.0%)
Hispanic	23 (26.1%)	171 (34.3%)
Past medical history: N (%)
Hypertension	63 (71.6%)	370 (74.1%)	0.585
Diabetes	27 (30.7%)	120 (24.0%)	0.228
Hypercholesterolemia	29 (33.0%)	136 (27.3%)	0.303
Atrial fibrillation or other arrhythmia	11 (12.5%)	51 (10.2%)	0.572
Coronary artery disease	15 (17.0%)	67 (13.4%)	0.404
Medications: N (%)
Anticoagulation use	21 (23.9%)	57 (11.4%)	0.003
Antiplatelet use	40 (45.5%)	192 (38.5%)	0.238
ICH characteristics: median (IQR) or N (%)
Hematoma volume, mL	15.2 (2.6–44.1)	14.0 (4.4–35.0)	0.489
ICH score	2 (2–3)	2 (1–3)	<0.001
Glasgow coma scale	7 (5–11)	11 (7–15)	<0.001
Location*
Lobar	28 (37.3%)	132 (31.1%)	0.286
Basal ganglia or thalamus	41 (54.7%)	243 (57.2%)	0.706
Cerebellum	4 (5.3%)	35 (8.2%)	0.489
Brainstem	3 (4.0%)	19 (4.5%)	1.000
Presence of intraventricular hemorrhage	56 (63.6%)	243 (48.7%)	0.011
Ventriculostomy	43 (48.9%)	104 (20.8%)	<0.001
Medical disease severity: mean (SD)
Acute Physiology and Chronic Health Evaluation II	20.6 (7.3)	15.0 (7.7)	<0.001
Admission laboratory values
Anemia, N (%)†	58 (65.9%)	126 (25.3%)	<0.001
Hemoglobin, g/dL, mean (SD)	11.3 (2.7)	13.6 (2.8)	<0.001
Platelets, ×103/dL, mean (SD)	212 (107)	226 (84)	0.197
International normalized ratio, mean (SD)	1.64 (1.53)	1.23 (0.57)	<0.001
Partial thromboplastin time, s, mean (SD)	33.8 (9.4)	30.7 (15.0)	0.078
Admission characteristics: median (IQR)
Length of stay, d	21 (9–35)	7 (4–16)	<0.001

ICH indicates intracerebral hemorrhage; IQR, interquartile range; and RBC, red blood cell transfusion.

^*14.8% missing data points.

^† Defined according to World Health Organization criteria: hemoglobin <13 g/dL in adult men and hemoglobin <12 g/dL in adult women. ³⁵

Patients with ICH receiving RBC transfusions were more likely to encounter aggregate composite thromboembolic or infectious complications occurring at any time during the hospitalization (64.8% versus 35.9%). However, when accounting for the timing of RBC transfusion in relation to these complications, there were no clear intergroup differences on incident composite thromboembolic or infectious complications between patients receiving and not receiving RBC transfusions (30.7% versus 35.9%; Table 2). In our multivariable logistic regression models, we similarly identified a relationship of RBC transfusion on aggregate complications throughout the hospitalization (adjusted odds ratio [OR], 3.31 [95% CI, 1.95–5.63], P<0.0001) but not with incident composite complications (adjusted OR, 0.71 [95% CI, 0.42–1.20], P=0.20).

Table 2.

Intergroup Differences for Complications During ICH Hospitalization

Complications at any time	RBC transfusion N=88	No RBC transfusion N=499	Incident complications	RBC transfusion N=88	No RBC transfusion N=499
Composite thromboembolic or infectious complications: N (%)
Any complication	57 (64.8%)	179 (35.9%)	Any complication	27 (30.7%)	179 (35.9%)
Thromboembolic complications: N (%)
MI	7 (8.0%)	16 (3.2%)	MI	0 (0.0%)	16 (3.2%)
DVT	11 (12.5%)	18 (3.6%)	DVT	5 (5.7%)	18 (3.6%)
PE	3 (3.4%)	12 (2.4%)	PE	0 (0.0%)	12 (2.4%)
Any thromboembolic event	18 (20.5%)	41 (8.2%)	Any thromboembolic event	5 (5.7%)	41 (8.2%)
Infectious complications: N (%)
Pneumonia	40 (45.5%)	92 (18.4%)	Pneumonia	16 (18.2%)	92 (18.4%)
Bacteremia	16 (18.2%)	18 (3.6%)	Bacteremia	9 (10.2%)	18 (3.6%)
UTI	22 (25.0%)	95 (19.0%)	UTI	11 (12.5%)	95 (19.0%)
Any infection	53 (60.2%)	167 (33.5%)	Any infection	24 (27.3%)	167 (33.5%)

DVT indicates deep venous thrombosis; ICH, intracerebral hemorrhage; MI, myocardial infarction; PE, pulmonary embolism; RBC, red blood cell transfusion; and UTI, urinary tract infection.

Intergroup differences of specific complication subtypes are depicted in Table 2. Though analyses of these complication subtypes were limited due to the number of specific complication events, we largely identified similar patterns where RBC‐transfused patients were more likely to encounter specific complication subtypes identified at any point during the hospitalization. Yet, when accounting for RBC transfusion timing, there were no intergroup differences in incident complication subtypes. There appeared to be increased incidence of bacteremia following RBC transfusion exposure; however, these analyses were limited by sample size.

When assessing the impact of RBC transfusions on clinical outcomes, we identified that patients receiving RBC transfusions were more likely to encounter poor outcomes (Table 3). However, when accounting for medical disease severity and ICH severity, there were no associations of RBC transfusions on either in‐hospital mortality (adjusted OR, 0.87; [95% CI, 0.45–1.66], P=0.67) or poor discharge neurological outcomes (adjusted OR, 2.45 [95% CI, 0.79–7.61], P=0.12) in our multivariable logistic regression analyses. Separate sensitivity analyses adjusting for number of RBC transfusions (as a categorical variable with 3 categories: no RBC transfusion, 1 RBC transfusion, and multiple RBC transfusions), ventriculostomy, surgical intervention (clot evacuation or decompressive craniectomy), or do‐not‐resuscitate/limitations of care within 24 hours of admission did not change the observed relationships of RBC transfusion on incident complications or clinical outcomes (data not shown).

Table 3.

Associations of RBC Transfusion on Clinical Outcomes

	RBC transfusion N=88	No RBC transfusion N=499	Unadjusted OR (CI)	Unadjusted P value	Adjusted OR (CI)*	Adjusted P value*
In‐hospital mortality	33 (37.5%)	123 (24.6%)	1.91 (1.17–3.11)	0.011	0.87 (0.45–1.66)	0.665
Poor discharge modified Rankin Scale score 4–6	78 (88.6%)	352 (70.5%)	5.14 (2.03–13.01)	<0.001	2.45 (0.79–7.61)	0.121

OR indicates odds ratio; and RBC, red blood cell transfusion.

^*Adjusted for the following covariates: sex, race, Acute Physiology and Chronic Health Evaluation II score, intracerebral hemorrhage score, and preceding antithrombotic medication use.

DISCUSSION

Liberal RBC transfusion approaches are currently being investigated in patients with acute brain injury given the reported impact that RBC transfusions have on improving cerebral oxygen delivery, thus providing the potential to improve outcomes in certain patient populations. ⁷ , ⁸ There have been consistent associations of low hemoglobin concentrations and poor ICH outcomes. ² , ³ , ⁴ However, it is unclear whether similar liberal RBC transfusion approaches are warranted in patients with ICH due to uncertainties over benefits, ¹⁰ and more specifically risks of these transfusions in this vulnerable patient population. ¹¹ In our single‐center, racially diverse cohort with spontaneous ICH, we identified that RBC transfusions were clinically administered to 15% of patients. Patients receiving RBC transfusions were sicker with more severe baseline disease characteristics, and when taking transfusion timing for each patient into account, we did not identify associations of RBC transfusion exposure on subsequent incident composite complications. And similarly, we did not identify significant relationships of RBC transfusions with poor ICH outcomes. Thus, our study provides initial evidence in patients with ICH that RBC transfusions themselves are not associated with relevant medical thromboembolic or infectious complications, which are known to have a deleterious impact on clinical ICH outcomes. ¹⁸ , ¹⁹ , ²⁰

Our single‐center cohort with ICH's RBC transfusion exposure prevalence and, separately, its ICH severity and ICH volumes appear to reflect what has been described in other single‐ and multicenter studies. ¹⁰ , ³⁶ , ³⁷ Yet, our findings differ from previous studies, which have identified relationships of RBC transfusions with such thromboembolic and infectious complications across a wide range of patient populations. ¹² , ¹³ , ¹⁵ , ¹⁷ , ³⁸ , ³⁹ , ⁴⁰ However, the absence of RBC transfusion and complication onset timing in many of these studies prevented an assessment of whether the RBC transfusion exposure occurred before the complication outcome. To this extent, a recent multicenter study identified that taking RBC transfusion timing into account, there were no associations of these transfusions with incident thrombotic complications. ⁴¹ Thus, our data in patients with ICH may similarly suggest that although RBC transfusions are often given to patients who are sicker and accrue more medical complications, there do not appear to be causal associations of RBC transfusions themselves on downstream thromboembolic or infectious complications. Similarly, our data also highlight the importance of accounting for RBC transfusion timing in relation to relevant outcomes of interest, as prior literature suggests that relevant incident complications after RBC transfusion can occur several days after the transfusion, ¹² , ³⁸ , ⁴¹ though it is currently unknown for how long a period after a transfusion such complication risks may be relevant.

It is worth noting that when we explored associations of RBC transfusions on specific complication subtypes, we identified a potential relationship between RBC transfusion exposure and bacteremia. Although our analyses for this specific outcome were limited by sample size, prior literature has identified relationships of RBC transfusion exposure on incident bloodstream infections. ⁴² RBC transfusions, specifically older aged units, can increase non‐transferrin‐bound iron, enhancing proliferation potential of microorganisms. ⁴³ , ⁴⁴ , ⁴⁵ Thus, these preliminary findings may necessitate a closer look to evaluate whether RBC transfusions confer risks for certain types of infections.

In our clinical outcome analyses, we identified that RBC transfusion recipients were more likely to encounter worse ICH outcomes. However, these patients had worse baseline medical disease severity, as well as ICH severity. Subsequently, when accounting for these underlying disease severity factors, we did not identify independent associations of RBC transfusions with poor ICH outcomes. Although a prior study using a large administrative data set identified that RBC transfusions are associated with worse ICH outcomes, it was notable that effect size estimates decreased when accounting for disease severity. ¹¹ Furthermore, among patients with more severe ICH requiring ventriculostomy placement in that study, there were no associations of RBC transfusions with poor outcomes. ¹¹ It is possible that our single‐center findings, with the high prevalence of intraventricular hemorrhage, similarly suggest that RBC transfusions do not independently cause poor outcomes. It could be specifically posited that RBC transfusions may provide differential risks and benefits based on ICH severity and perhaps intraventricular hemorrhage presence. In this regard, it is likely that RBC transfusions do not uniformly provide benefit or harm across all patients. There may be specific transfusion indications and scenarios that provide more therapeutic benefit, yet these factors remain to be determined. Though our study data did not suggest a therapeutic benefit of RBC transfusion on ICH outcomes, a prior study has suggested an association of RBC transfusions with lower ICH mortality. ¹⁰ Thus, further work is required to better identify the specific benefits and risks of RBC transfusion approaches in these patients in efforts to improve outcomes.

Though the presence of granular ICH hospitalization data (ie, ICH and medical illness severity, RBC transfusion timing data, and complication timing data) was a unique strength to our analyses, there are several limitations that require mentioning. Due to the sample size, our study may have lacked power to demonstrate a significant association of RBC transfusion on functional outcomes. Our estimate for the association between RBC transfusion and poor discharge modified Rankin Scale score may reflect clinical relevance despite the lack of statistical significance, and larger studies will be needed to confirm our observed relationships. Similarly, given our smaller single‐center cohort, we were unable to assess for relevant effect differences of RBC transfusions on outcomes when stratifying by age or sex. We were also unable to assess the impact of RBC transfusions on long‐term outcomes. Although hospitalization complications and hospital mortality have largely been used as outcomes timepoints in the transfusion literature, transfusions may affect ICH outcomes at follow‐up time points beyond the acute hospitalization. Additionally, because the RBC‐transfused group included sicker patients with longer length of stay, unmeasured confounding or diagnostic acquisition bias between our groups may have affected our results and will need to be considered in future studies. Furthermore, although sensitivity analyses were performed adjusting for number of RBC transfusions received, it is possible that repeated RBC transfusions at different points during the hospitalization may alter the risk for complications that were not addressed in our study. Our study also lacked detailed data regarding indication for RBC transfusion and hemoglobin trends during hospitalization. Although it is presumed that most of the RBC transfusions were given to correct hemoglobin levels that were below 7 g/dL as per local clinical practice and protocols, it is possible that other active issues (ie, cardiac event, sepsis, active hemorrhage, severe hypotension) could have factored into these treatment decisions. This treatment indication confounder could potentially affect both complication and clinical outcomes. Although ICH and medical illness severity were adjusted for in all models, these are baseline characteristics and would not reflect the disease severity that occurs at the time of the transfusion. Thus, further prospective efforts will be needed to factor these important disease state changes into hemoglobin levels and RBC transfusion's impact on outcomes. Similarly, causes of anemia necessitating RBC transfusions were not characterized in this study. It is possible that the underlying reason for anemia may differentially affect RBC transfusions on outcomes, and future studies will be needed to clarify this factor. Additionally, we did not include patients with ICH caused by vascular malformation, aneurysm, or malignancy, so our findings may not translate to patients who require neurosurgical resection of lesional causes of ICH. These patients may be more prone to developing a transfusion requirement, so future work is required to assess the generalizability of our findings and the potential differential impacts that RBC transfusions have across different types of patients with ICH. Finally, it is increasingly recognized that RBC transfusions are not uniform. Certain donor and RBC transfusion unit characteristics (ie, storage time and irradiation) are known to contribute to the “storage lesion” and affect subsequent transfusion efficacy. ⁴⁶ , ⁴⁷ Future efforts will be required to assess vein‐to‐vein (recipient‐to‐donor) characteristics to better identify best transfusion practices moving forward.

CONCLUSIONS

In conclusion, in this retrospective analysis of a prospective cohort of patients with spontaneous ICH, RBC transfusion was not associated with incident hospital complications or poor clinical ICH outcomes when accounting for disease severity and timing of transfusions. Additional research in larger cohorts is needed to assess the independent risks and benefits of RBC transfusions in patients with ICH.

Sources of Funding

Dr Roh and this work were supported by National Institutes of Health National Heart, Lung, and Blood Institute grants K23HL151901, R01HL148151, and a National Blood Foundation Science Research Grant.

Disclosures

None.