Sickle Pain Research Articles

Use of Conventional Transfusion Thresholds Contributes to Ongoing Iron Overload Issues in Patients with Homozygous (SS) Sickle Cell Disease

Introduction: Homozygous sickle cell disease is characterized by chronic anemia which contributes to a clinical course characterized by recurrent pain crisis episodes. These episodes are usually managed with the use of packed red blood cell products. Randomized data is currently available that supports lower transfusion thresholds in non-sickle cell related conditions including but not limited to patients undergoing orthopedic procedures, cardio-vascular interventions and those needing intensive care. Due to lack of similar randomized trials in patients with sickle cell disease, recommendations from other trials are applied to patients with sickle cell diseases as well. However, this has the potential of worsening iron overload states that patients with sickle cell disease usually suffer from. Methods: Patients with homozygous SS sickle cell disease were evaluated with regarding to transfusion support given during hospitalization for vaso-occlusive pain crisis episodes. The hemoglobin threshold that was used for deciding whether or not to give packed red cell transfusion was studied in patients who were previously getting periodic red blood cell exchange procedures for chronic sickle cell related pain. Serum ferritin levels during the period of exchange transfusion support was compared with levels during simple transfusions. 8 patients were selected from the cohort of patients with homozygous sickle cell disease who had been receiving elective packed red blood cell exchanges. Patients with ferritin levels persistently remaining above 1000 ng/ml were then evaluated with regard to transfusion thresholds used for simple transfusion support during hospitalization for pain crisis episodes. Results: Six patients had persistently high ferritin levels. Thresholds for simple transfusion in this group were studied. A total of 30 units of packed red blood cells were found to be transfused over a 6-month period. During this period only one patient required an exchange transfusion session. 2 out of 30 units were given for a Hgb level above 7 g/dl. The majority, representing 24 out of the total 30 pack red blood cell units were given above a Hgb threshold of 6.0 g/dl. Only 4 units were given using a Hgb threshold less than 6 g/dl. Mean ferritin level before and after the period of simple transfusion support was 6097 ng/ml and 6076 ng/ml respectively. Mean Hgb level in while on exchange transfusion was 7.4 g/dl and it was 6.9 g/dl in those receiving a simple transfusion protocol. Conclusions: Transfusion threshold used in patients with homozygous SS sickle cell disease appears to be similar to patients without sickle cell disease. Current practice based on studies including TRICC and TRISS is to keep the Hgb level above 7 g/dl. This has been shown to be safe and in fact even improves patient outcomes. However, in patients with sickle cell disease this may not be appropriate since their baseline Hgb levels are lower to begin with. Also, transfusions don't appear to improve Hgb levels considerably. These patients also tend to have iron overload at baseline which likely will not improve unless all transfusions are limited. Therefore, applying a lower transfusion threshold would be recommended to avoid acute transfusion related issues and long-term iron overload problems in patients with SS disease.

Characteristics of Emergency Department Visits Made by Individuals With Sickle Cell Disease in the U.S., 1999–2020

Individuals living with sickle cell disease experience high levels of morbidity that result in frequent utilization of the emergency department. The objective of this study was to provide updated national estimates of emergency department utilization associated with sickle cell disease in the U.S. Data from the National Hospital Ambulatory Medical Care Survey for the years 1999-2020 were analyzed. Complex survey analysis was utilized to produce national estimates overall and by patient age groups. On average, approximately 222,612 emergency department visits occurred annually among individuals with sickle cell disease, a nearly 13% increase from prior estimates. The annual volume of emergency department visits steadily increased over time, and pain remains the most common patient-cited reason for visiting the emergency department. Patient-reported pain levels for individuals with sickle cell disease were high, with 64% of visits associated with severe pain and 21% associated with moderate pain. Public insurance sources continue to cover most visits, with Medicaid paying for 60% of visits and Medicare paying for 12% of visits. The average time spent in the emergency department increased from previous estimates by about an hour, rising to approximately 6 hours. The average wait time to see a provider was 53 minutes. Utilization of the emergency department by individuals living with sickle cell disease remains high, especially for pain. With more than half of patients with sickle cell disease reporting severe pain levels, emergency department staff should be prepared to assess and treat sickle cell disease-related pain following evidence-based guidelines and recommendations. The findings of this study can help improve care in this population.

Single nucleotide polymorphisms and sickle cell disease-related pain: a systematic review.

Scientists have speculated genetic variants may contribute to an individual's unique pain experience. Although research exists regarding the relationship between single nucleotide polymorphisms and sickle cell disease-related pain, this literature has not been synthesized to help inform future precision health research for sickle cell disease-related pain. Our primary aim of this systematic review was to synthesize the current state of scientific literature regarding single nucleotide polymorphisms and their association with sickle cell disease-related pain. Using the Prisma guidelines, we conducted our search between December 2021-April 2022. We searched PubMed, Web of Science, CINAHL, and Embase databases (1998-2022) and selected all peer-reviewed articles that included reports of associations between single nucleotide polymorphisms and sickle cell disease-related pain outcomes. Our search yielded 215 articles, 80 of which were duplicates, and after two reviewers (GG, JD) independently screened the 135 non-duplicate articles, we retained 22 articles that met the study criteria. The synthesis of internationally generated evidence revealed that this scientific area remains predominantly exploratory in nature, with only three studies reporting sufficient power for genetic association. Sampling varied across studies with a range of children to older adults with SCD. All of the included articles (n = 22) examined acute pain, while only nine of those studies also examined chronic pain. Currently, the evidence implicating genetic variation contributing to acute and chronic sickle cell disease-related pain is characterized by modestly powered candidate-gene studies using rigorous SCD-pain outcomes. Effect sizes and directions vary across studies and are valuable for informing the design of future studies. Further research is needed to replicate these associations and extend findings with hypothesis-driven research to inform precision health research.

Candidate gene association study suggests potential role of dopamine beta-hydroxylase in pain heterogeneity in sickle cell disease.

Introduction: Pain is a lifelong companion of individuals with sickle cell disease (SCD) and has a severe impact on their quality of life. Both acute crisis pain and chronic non-crisis pain exhibit high variability between individuals, making it difficult to effectively manage sickle cell-related pain. We investigated the role of dopamine beta-hydroxylase (DBH) gene polymorphisms on pain variability in SCD. DBH is a key enzyme in the catecholamine biosynthesis pathway that catalyzes the conversion of dopamine to norepinephrine, both of which are known mediators of pain and pain-related behaviors. Methods: Acute crisis pain-related utilization and non-crisis chronic pain scores of 131 African Americans with SCD were obtained. Results and discussion: Association analyses revealed that the T allele of upstream variant rs1611115 and downstream variant rs129882 correlated with higher severity of chronic pain in an additive model. On the other hand, the A allele of missense variant rs5324 associated with lower risk of both acute crisis pain and chronic pain. Similarly, the C allele of intronic variant rs2797849 was associated with lower incidence of acute crisis pain in the additive model. In addition, tissue-specific eQTL revealed that the T allele of rs1611115 correlated with decreased expression of DBH in the frontal cortex and anterior cingulate cortex (GTEx), and decreased expression of DBH-AS1 in blood (eQTLGen). Bioinformatic approaches predicted that rs1611115 may be altering a transcription factor binding site, thereby, contributing to its potential effect. Taken together, findings from this study suggest that potential functional polymorphisms of DBH may modulate pain perception in SCD.

Efficacy of non-pharmacological interventions to reduce pain in children with sickle cell disease: A systematic review.

Pain is the clinical hallmark of sickle cell disease (SCD) leading to hospitalization, psychological sequelae and a decreased health-related quality of life. The aim of this systematic literature review is to evaluate the efficacy of non-pharmacological interventions in reducing sickle cell related pain in children with SCD. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, a comprehensive literature search up until October 2022 was performed to identify studies that investigated the efficacy of non-pharmacological interventions on (1) pain frequency and/or intensity, and (2) analgesic and health service use in children with SCD until the age of 21. Both randomized controlled trials (RCTs) and quasi-experimental designed (QED) studies were considered for inclusion. Ten articles (five RCTs and five QED studies) with 422 participants were included. They investigated cognitive behavioural therapy (CBT) (n=5), biofeedback (n=2), massage (n=1), virtual reality (n=1) and yoga (n=1). The majority of the interventions were psychological (n=7) and were performed in the outpatient clinic (n=6). CBT and biofeedback significantly reduced frequency and/or intensity of SCD-related pain in outpatient settings, while virtual reality and yoga significantly reduced pain in inpatient settings. Biofeedback also significantly reduced analgesic use. None of the included articles reported reduced health service use. Non-pharmacological interventions may be effective in reducing pain in paediatric patients with SCD. However, due to the heterogeneity of the included studies a quantitative analysis could not be performed. Awaiting further supporting evidence, healthcare providers should consider implementing these interventions as valuable part of a comprehensive pain management strategy plan.

Increasing Incentive Spirometry Use in Patients with Sickle Cell Disease Admitted to Children's Mercy Hospital

Introduction: Acute chest syndrome is one of the leading causes of morbidity and mortality in patients with sickle cell disease. The National Heart, Lung, and Blood Institute (NHLBI) recommends providing ten breaths of incentive spirometry (IS) every two hours while awake for patients with sickle cell disease admitted to the hospital to help prevent development of acute chest syndrome. Methods: We reviewed provision of IS at Children's Mercy Hospital (CMH) in Kansas City, Missouri between 08/01/2021 and 11/01/2021. Data were collected and the target population was identified via a report generated from the electronic medical records of those patients admitted with sickle cell disease and vaso-occlusive pain requiring continuous opioid infusion. We reviewed the frequency with which IS was offered each hospital day and found that during that 3-month time period, no patients were offered IS at the frequency recommended by the NHLBI. Meetings with stakeholders identified that IS orders were inconsistent between electronic medical record order sets and were not based on current NHLBI recommendations. To address this potential root cause, order sets were updated to match NHLBI recommendations. We then reviewed provision of IS following implementation of standardized IS orders between 12/21/2021 and 3/14/2022. Our primary aim with our initial plan-do-study-act (PDSA) cycle was to increase the frequency IS was being offered to patients to meet NHLBI guidelines. Results: Between 08/01/2021 and 11/01/2021, there were 285 hospital days with patients admitted to CMH with a sickle cell vaso-occlusive pain. We excluded days of admission and discharge (94 days). Of 191 full hospital days, only 53% (101/191) had IS documented at all. When IS was documented, 0% of patients were offered the recommended frequency of IS and the median time between IS offerings was 6.3 hours. Following implementation of updated orders on 12/21/2021 IS was offered to patients at the recommended frequency 1% of the time, and the median hours between when IS was offered decreased to 5.9 hours. Conclusion: The initial goal of this project was to increase the daily occurrences of IS offered to sickle cell patients admitted to the hospital with vaso-occlusive pain to meet the NHLBI recommended frequency from 0% to 10% over a 3-month period following the implementation of updated IS orders within Cerner powerplans. Further PDSA cycles will continue to refine our approach to increasing frequency IS is offered to the patient and documented in the medical record. Subsequent PDSA cycles will also focus on increasing patient use of IS as well as analyzing supplemental oxygen use before and after each intervention as a patient outcome measure.

Challenges of Diagnosing Headache in Sickle Cell Disease, a Unique Case of Polycythemia Vera and Essential Thrombocytosis in a Patient with Sickle Cell beta0 Thalassemia

Introduction: Little is known of the relationship between myeloproliferative neoplasm (MPN) and sickle cell disease (SCD), possibly due to under diagnosis from symptom overlap. Few studies exist documenting cases of concomitant MPN in SCD patients, likely because the confounding presence of reactive thrombocytosis in SCD and masking of polycythemia in SCD making the diagnosis of essential thrombosis (ET) and polycythemia vera (PV) difficult. Case Presentation: Here, we report a case of a 38-year-old male with beta 0 thalassemia (HbSB0) SCD who developed a chronic, and unremitting headache of 2 months. Neurological workup of his headache was unremarkable and headache remained unresponsive to various pain medications used by the patient for sickle cell associated pain crises. Laboratory values on presentation were remarkable for WBC 11 k/uL, HgB 10.9 g/dL, platelets 994 k/uL, MCV 72, reticulocyte count 7.0%. A thorough analysis of vasomotor symptoms and laboratory values, when trended over 20 years (table 1), demonstrated that headaches were likely secondary to hyperviscosity, as noted by platelet uptrend and inappropriate hemoglobin elevation for his SCD genotype; in which the expected hemoglobin level is between 6-8g/dL. Laboratory studies demonstrated a JAK2 mutation in peripheral blood with no BCR-ABL mutation detected, excluding chronic myeloid leukemia (CML). Subsequent bone marrow biopsy demonstrated hypercellular marrow (90-95%) with marked erythropoiesis and relatively mild increased granulocytic and megakaryocytic hematopoiesis and mild increase in reticulin fibers, without dysmyelopoiesis; thus excluding myelodysplastic syndrome (MDS). Mutation analysis confirmed JAK2 Val617Phe mutation. Concurrent flow cytometry analysis showed no evidence for leukemia or lymphoproliferative disorder. Together with biopsy data, laboratory data and clinical presentation, the patient was diagnosed with polycythemia vera and essential thrombocytosis. The patient was subsequently managed with Hydroxyurea, with resolution of symptoms presumably due to improvement in blood viscosity due to lowering of platelet levels to 464k/uL. Discussion: Our report highlights a unique association between MPN in a patient with SCD, diagnostic challenges, and its multifaceted treatment. Our patient presented with unremitting headaches, which can be secondary to either SCD or MPN alone. In patients with SCD severe headache can be associated with ischemic stroke due to vaso-occlusion, hemorrhage, venous sinus thrombosis, aneurysms, meningitis, medication withdrawal or tolerance, bony infarcts, and osteomyelitis. The wide differential diagnosis of headaches in SCD complicates the finding of MPN amongst these patients, and without frequent laboratory monitoring, concomitant vasomotor symptoms would likely remain unnoticed in the patient. Furthermore, our report describes the first documented association of a JAK2 Val617Phe mutation in a patient with SCD. Our case also outlines the use of hydroxyurea as a double edged sword. Interestingly in our patient, hydroxyurea initiation acted as a dual therapy for the management of SCD, through reducing pain crisis episodes, and MPN via platelet count reduction, thereby preventing symptoms of hyperviscosity. Overall, this case highlights a distinctive example of PV and ET in a patient with SCD and its diagnostic challenges, and the first case in the literature to describe JAK2 Val617Phe mutation. Further, our case emphasizes the need to consider vasomotor symptoms and perform a critical analysis of laboratory trends in SCD patients. Future studies may consider a multi-institution retrospective analysis of thrombocytosis in SCD patients to determine if MPN is underdiagnosed in SCD patients. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Cannabidiol Attenuates Chronic and Acute Hyperalgesia in Sickle Mice By Reducing Inflammation and Oxidative Stress

Pain is a major comorbidity of sickle cell disease (SCD) leading to hospitalization, opioid use and reduced survival. It can present as both chronic pain and/or unpredictable episodes of intense acute pain. Hydroxyurea (HU) is the mainstream FDA approved treatment for SCD, but its effect on reducing pain remains to be understood. A larger number of people with SCD use cannabis products for pain relief compared to those with other conditions. Cannabidiol (CBD) is one of the major constituents of Cannabis sativa, second to tetrahydrocannabinol, and has gained attention for its ability to treat pain without intoxicating side effects. CBD has been shown to decrease inflammation, oxidative stress, and inhibit mast cell activation, all of which occur in SCD. Thus, we hypothesize that CBD will ameliorate both chronic and acute hyperalgesia in humanized homozygous BERK sickle mice (called sickle) by inhibiting mast cell activation and decreasing inflammation and oxidative stress. To simulate the clinical condition, we treated female sickle mice intraperitoneally with [i] vehicle (1:1:18 DMSO:Tween-20:saline), [ii] HU (50 mg/kg/d HU), [iii] CBD (20 mg/kg/d) or [iv] HU + CBD and determined their effect on chronic and acute hyperalgesia (pain). Sickle mice treated with synthetic CBD alone or cotreatment with HU+CBD daily showed significantly reduced chronic mechanical (p<0.001) and cold (p<0.001) hyperalgesia compared to baseline after 7 days of treatment, which was maintained for up to 14 days. HU decreased mechanical (p<0.01) but not cold hyperalgesia after 14 days compared to baseline. Thus, CBD independently attenuates chronic hyperalgesia, whereas HU may have a modest effect on chronic pain. Following the initial 14 days of treatment above, we incited acute hyperalgesia by treating sickle mice with hypoxia/reoxygenation (H/R; 3 hours of hypoxia at 8% O2 and 92% N2, followed by 1 hour of reoxygenation at normoxia) on days 15 (H/R-1) and 18 (H/R-2). We observed that CBD, HU, and HU+CBD treatments were able to prevent an increase in H/R-incited hyperalgesia (acute response). CBD alone and HU+CBD significantly reduced mechanical (p<0.001) and cold hyperalgesia (p<0.001) compared to baseline following incitement of both H/R-1 and H/R-2, and up to 25 days, the last period of observation. HU alone did not show a significant decrease in mechanical or cold hyperalgesia compared to baseline following incitement of either H/R event, except for cold hyperalgesia 72h post-H/R-2 (p<0.05). CBD and HU+CBD treatments also reduced non-evoked cold avoidance compared to baseline in sickle mice, which spent significantly more time (p<0.01) in a cold chamber (4°C) 7d after H/R-2 (day 25), but HU alone did not. Thus, HU has a modest or no effect on different features of sickle pain, while CBD is able to ameliorate both chronic and acute pain. We next investigated the mechanism of CBD's analgesic effect in sickle mice. Following 9 days of daily treatment, we observed that CBD decreased total and degranulating mast cells (p<0.05 and p<0.01, respectively) in the skin compared to vehicle, and a reduction in tryptase (p<0.05), a marker of mast cell activation, in the skin secretagogue. CBD treatment decreased substance P (p=0.05) and malondialdehyde, (p<0.05), markers of neuroinflammation and oxidative stress respectively, in the skin secretagogue, and serum amyloid P (p<0.05), a marker of inflammation, in plasma. CBD significantly decreased inflammatory cytokines IL-3, which promotes mast cell proliferation, TNFα, a hallmark feature of cytokine storm, and MIP-1α and RANTES, which contribute to leukocyte recruitment. Thus, CBD attenuates inflammation, neuroinflammation and oxidative stress in sickle mice and may ameliorate leukocyte activities, a hallmark feature of SCD. We demonstrate that CBD is effective in attenuating chronic hyperalgesia and preventing acute pain by decreasing inflammation and oxidative stress. The effect of HU on reducing pain following H/R and chronic pain are modest and specific to certain characteristic features of sickle pain. Importantly, HU does not appear to interfere with the analgesic effect of CBD in sickle mice, which shows promise for CBD treatment in persons with SCD on HU. The availability of a >99% CBD-extract (Epidiolex) approved by the FDA to treat some forms of epilepsy may help facilitate clinical trials for assessing the effects of CBD on pain in persons with SCD.

Pklr Variants Associated with Acute Pain in Sickle Cell Disease Influence ATP Concentrations in Red Blood Cells

Background: We previously demonstrated association of PKLR intron 2 variants with hospitalization rate for acute pain in people with sickle cell disease (SCD) and utilized allele-specific expression analysis to show that these variants influence PKLR activity (Wang et al, 2022). Pyruvate kinase (gene PKLR, protein PKR) is a rate-limiting enzyme in glycolysis. Reduced PKR activity leads to an increase in intracellular 2,3-diphosphoglycerate (2,3-DPG), and a concomitant decrease of adenosine triphosphate (ATP), factors that promote sickle hemoglobin (HbS) polymerization and red blood cell (RBC) sickling. On this basis, we explored how the "high risk" PKLR intron 2 variants affect levels of PKR protein expression, 2,3-DPG, ATP, oxygen dissociation (p50) and sickling kinetics (t50). Methods: We studied a total of 416 subjects which included 125 HbSS, 89 HbAS, and 202 ethnic-matched healthy controls (HbAA) enrolled under protocol NCT03685721 approved by the NHLBI Institutional Review Board. DNA was genome scanned using Ilumina's Infinium "MEGA" chip (1.7m markers). The results were quality controlled followed by genotype imputation based on the 1000 Genomes Project phase 3 data using the Michigan Imputation Server. Whole blood levels of ATP and 2,3-DPG were measured using LC-MS/MS with LLOQ at 50.0 μg/mL and converted to intracellular concentrations by dividing by the hematocrit (as a fraction). PKR was detected by antibody-based capture and detection using an electrochemiluminescence immunoassay (Meso Scale Discovery, Rockville, MD, USA) and the signal normalized to a control sample. A Hemox Analyzer [TCS, Scientific Corp, New Hope, PA] was used to obtain p50 values (defined as the partial pressure of oxygen at which Hb is 50% saturated with oxygen). t50 is single parameter measure of sickling kinetics (Dunkelberger et al, 2018). Single variant analyses (under additive genetic model adjusted for age and sex) were conducted in each of the Hb sub-populations for associations between the 7 PKLR variants (intron 4 - rs2071053, and intron 2 -rs8177970, rs116244351, rs114455416, rs12741350, rs3020781, and rs8177964) and the 5 parameters (PKR, 2,3-DPG, ATP, p50 and t50). False-discovery rate (FDR) adjusted p-values were calculated to account for the multiple testing issue. Results: Table 1A shows levels of the 5 parameters (ATP/HCT, 2,3-DPG/HCT, PKR, p50 and t50) in the 3 Hb genotypic groups (HbAA, HbAS and HbSS). Because patients with SCD have variable anemia, ATP and 2,3-DPG were normalized against HCT. The observed trending higher ATP / HCT and significantly elevated 2,3-DPG /HCT in HbSS compared to HbAS and to HbAA are consistent with previous reports (Poillon et al, 1990). HbSS subjects also had higher PKR protein expression, as well as right-shifted p50 values, compared to HbAS and HbAA (Table 1A), which suggest HbSS RBCs have lower specific activity of PKR. A one-way ANOVA showed that the differences in these mean values were highly significant (Table 1A). All 7 PKLR variants were associated with ATP levels in the HbAS group, of which 4 (rs8177970, rs116244351, rs114455416 and rs8177964) in intron 2 remained statistically significant after multiple testing adjustment (Table 1B). We also identified association between 3 variants (intron 2 - rs12741350, rs3020781, intron 4 - rs071053) and 2,3-DPG levels in the HbSS, as well as t50 in the HbAS group. Conclusion: ATP is essential for maintaining RBC membrane integrity and shape; reduced ATP dehydrates RBCs and promotes sickling. In a previous report, a PKLR intron 2 'high-risk" haplotype was implicated in acute sickle pain by affecting PKLR expression (Wang et al, 2022). In this follow-up study, we show that the same intron 2 "high-risk" haplotype negatively affects ATP levels when accounting for PKR expression, thus providing a biological basis for PKLR as a genetic modifier of SCD pain presentation. 3 of the 7 variants are also associated with elevated 2,3-DPG levels in HbSS as well as t50 (a single parameter that depends primarily on sickling kinetics) in HbAS. The variant associations are observed more clearly in HbAS but not in HbSS, possibly because of the much more homogeneous cell population in HbAS. We conclude that PKLR intron variants may directly contribute to the severity and frequency of acute pain episodes in SCD, thus additional studies with larger sample sizes are warranted. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Enrollment Lessons from a Biological Assignment Study of Marrow Transplantation versus Standard Care for Adolescents and Young Adults with Sickle Cell Disease: Considerations for Future Gene and Cellular Therapy Trials

We previously conducted a single-arm feasibility study (STRIDE1) of myeloablative bone marrow transplantation (BMT) in adolescents and young adults with sickle cell disease (SCD). The trial identified donors before entry, enrolled well, and found no unexpected regimen-related toxicity. Although many single-arm studies have been published, there are no controlled trials of either BMT or gene therapy in SCD. Therefore, we designed a comparative trial by biological assignment (available donor versus no donor). This multicenter National Institutes of Health-funded study (Blood and Marrow Transplant Clinical Trials Network 1503; STRIDE2) enrolled patients between 2016 and 2021 at 35 sites. Lagging recruitment led to study closure, and here we report the impediments to accrual. The BMT regimen and entry criteria were from STRIDE1, and 2-year survival was the primary endpoint. To minimize selection bias from prior HLA typing, STRIDE2 excluded individuals with previously identified donors. Accrual was stopped at 69% of target (138 enrolled; assigned 28 with donor, 96 with no donor). Barriers to enrollment included lower than expected frequency of HLA-matched related and unrelated donors; loss of enrollees owing to previously identified donors; conventional care arm dissuading some seeking BMT; challenging short-term endpoints in SCD, including incomplete documentation of sickle pain episodes; state Medicaid (primary insurers of SCD) denial of BMT coverage for adult SCD despite the study having secured Coverage with Evidence Development from the Center for Medicare & Medicaid Services; slowed accrual in 2019 to 2021 during the Coronavirus disease 2019 pandemic; and restriction of BMT resourcing for nonmalignant diseases by academic medical (cancer) centers. Social obstacles and access to BMT centers also limited entry, as did practitioner and participant concerns over suitability, cost, and toxicity. Planning for future controlled trials of curative therapy in SCD and other nonmalignant diseases likely will meet these enrollment challenges. Lessons from this trial may aid the development of future comparative studies.

A Novel Measure of Pain Location in Adults with Sickle Cell Disease

BackgroundPain intensity remains a primary focus clinically for sickle cell disease pain assessment despite the fact that pain quality and pain location and distribution are critical for clinical diagnosis and treatment of its etiology. However, in part because of measurement issues, scant evidence is available about pain location or its relationship to intensity and quality in adults with SCD. AimOur study aim was to examine sickle cell disease pain location for relationships with pain quality and intensity measured in outpatient and inpatient settings. MethodsWe used an existing longitudinal dataset prospectively collected with the valid and reliable tablet-based PAINReportItⓇ. Adults with sickle cell disease (n = 99) reported pain location, intensity, and quality during a routine outpatient clinic visit and again during a subsequent hospitalization. From their digital body outline drawings and using the ImageJ software, we computed the pain-affected body surface area. With Pearson's correlations and paired t tests, we examined relationships between pain-affected body surface area and other pain variables across outpatient and inpatient visits. ResultsThe mean pain-affected body surface area was 14.4% ± 15.0% of the total body surface area for outpatient visits (min-max: 0.0%-90.2%) and 13.5% ± 14.7% (min-max: 0.0%-73.0%) for inpatient stay. Pain-affected body surface area was positively correlated with pain quality scores for both visits but not significantly correlated with pain intensity at either visit. Compared with the outpatient visit, mean pain intensity for inpatient stay was higher (p < .001); pain quality (p = .12) and pain-affected body surface area (p = .60) did not differ significantly between visits. ConclusionsUnknown is the explanation for pain-affected body surface area association with SCD pain quality but not pain intensity at outpatient and inpatient visits. Additional research is warranted to explore these findings and examine the clinical utility of pain-affected body surface area for chronic sickle cell disease pain and acute sickle cell disease crisis pain.

Sickle cell disease chronic joint pain: Clinical assessment based on maladaptive central nervous system plasticity.

Chronic joint pain (CJP) is among the significant musculoskeletal comorbidities in sickle cell disease (SCD) individuals. However, many healthcare professionals have difficulties in understanding and evaluating it. In addition, most musculoskeletal evaluation procedures do not consider central nervous system (CNS) plasticity associated with CJP, which is frequently maladaptive. This review study highlights the potential mechanisms of CNS maladaptive plasticity related to CJP in SCD and proposes reliable instruments and methods for musculoskeletal assessment adapted to those patients. A review was carried out in the PubMed and SciELO databases, searching for information that could help in the understanding of the mechanisms of CNS maladaptive plasticity related to pain in SCD and that presented assessment instruments/methods that could be used in the clinical setting by healthcare professionals who manage chronic pain in SCD individuals. Some maladaptive CNS plasticity mechanisms seem important in CJP, including the impairment of pain endogenous control systems, central sensitization, motor cortex reorganization, motor control modification, and arthrogenic muscle inhibition. Understanding the link between maladaptive CNS plasticity and CJP mechanisms and its assessment through accurate instruments and methods may help healthcare professionals to increase the quality of treatment offered to SCD patients.

Pain in sickle cell diseases; physicians' knowledge, attitude, and barriers: A cross sectional study.

To assess the status of acute pain management in sickle cell disease patients, and to explore the association between professional experience and therapeutic preferences among the physicians for the management of sickle cell disease-related acute pain management. The cross-sectional study was conducted from June to September 2018 and comprised physicians from 20 hospitals across Saudi Arabia. Data was collected using a 13-item survey form investigating physicians' general information and related barriers regarding acute pain management in sickle cell disease patients. Data was analysed using SPSS 25. Of the 300 individuals approached through emails, 201(67%) responded. There were 122(61%) males and 78(39%) females; 126(63%) had experience <5 years, while 41(20%) had experience >10 years; the largest group of physicians belonged to Internal Medicine 46(23%); 41(20.4%) came across sickle cell disease patients 'very often' and 31(15.4) had never come across such a patient. There was no significant association between professional experience and therapeutic management preferences (p>0.05). Physicians' knowledge, attitude and practice related to acute pain management in sickle cell disease patients was adequate. More awareness is needed for optimal management of pain in such patients.

Arginine Therapy and Cardiopulmonary Hemodynamics in Hospitalized Children with Sickle Cell Anemia: A Prospective, Double-blinded, Randomized Placebo-controlled Clinical Trial.

Rationale: Acute changes in cardiopulmonary hemodynamics that include tricuspid regurgitant jet velocity (TRV) elevation measured by Doppler echocardiography are often encountered during sickle cell vasoocclusive pain and acute chest syndrome (ACS). Arginine and nitric oxide depletion develop in patients with these complications. Arginine administration may therefore improve nitric oxide bioavailability and potentiate pulmonary vasodilatation. Objectives: To evaluate effects of l-arginine supplementation on Doppler indices of cardiopulmonary hemodynamics in children with sickle cell anemia experiencing pain. Methods: This was a prospective, double-blinded, randomized placebo-controlled trial of oral arginine in children with sickle cell anemia age 5-17 years hospitalized with severe pain and/or ACS. Measurements and Main Results: Blood biomarkers and Doppler echocardiographic indices of cardiopulmonary hemodynamics were measured before and after supplementation. The mean change in TRV, pulmonary artery systolic pressure, mean pulmonary artery pressure, and other indices of cardiopulmonary hemodynamics were tested with paired Student's t test and correlated with markers of arginine bioavailability using Pearson correlation. Sixty-six children were randomized into arginine versus placebo groups. An elevated TRV ⩾ 2.5 m/s was seen in 40 (61%) patients. A Day 5 Doppler echocardiogram was performed in 47 patients who remained hospitalized. A greater reduction in median TRV occurred in the arginine group than placebo (22.2%, n = 22 vs. 3.8%, n = 25; p < 0.01). A larger percentage increase in global arginine bioavailability was associated with a lower TRV after 5 days of supplementation (r = -0.533; P = 0.001). Significant differences in multiple indices of cardiopulmonary hemodynamics and mean N-terminal pro B-type brain natriuretic peptide were also noted after arginine therapy. Conclusions: Oral arginine supplementation improves cardiopulmonary hemodynamics during sickle cell disease vasoocclusive pain and ACS.Clinical trial registered with Pan African Clinical Trial Registry https://pactr.samrc.ac.za/Search.aspx (PACTR201611001864290).

P124: EFFICACY OF NON-PHARMACOLOGICAL INTERVENTIONS TO REDUCE PAIN IN CHILDREN WITH SICKLE CELL DISEASE: A SYSTEMATIC REVIEW

Background: Pain is the clinical hallmark of sickle cell disease (SCD) and leads to frequent emergency department visits, psychological sequelae and a decreased health-related quality of life. Although pharmacological treatments to target and prevent pain are evolving, children still experience frequent pain. Although pharmacological treatments are effective, they are accompanied by side effects. Therefore, complementary non-pharmacological pain strategies are needed. The literature on this topic is heterogeneous and we urgently require an evaluation of the evidence supporting efficacy of non-pharmacological interventions in reducing the frequency and intensity of sickle cell related pain in children with SCD. Aims: The aim of this systematic review is to evaluate the evidence on the efficacy of non-pharmacological interventions in reducing the frequency and intensity of sickle cell related pain in children with SCD. Methods: We performed a literature search through October 2021 using the terms ‘sickle cell’, ‘pain’, ‘psychotherapy’, ‘analgesic’, and ‘health service’. We included randomized controlled trials and quasi-experimental studies that investigated the efficacy of non-pharmacological interventions on (1) pain frequency and intensity, and (2) analgesic and health service use in children with SCD. Results: Eleven articles including 441 participants were included. Nine studies performed in the outpatient clinic investigated the efficacy of cognitive behavioral therapy, biofeedback, and massage. Two studies performed during hospital admission included virtual reality and yoga. Five studies reported significant reductions in the frequency and/or intensity of pain. One study reported a significantly reduced analgesic use. The remaining six studies did not report a reduction in pain related outcomes. Conclusion: The evidence for non-pharmacological interventions to reduce pain in children with SCD seems promising, but due to heterogeneity of the included/published studies no firm conclusions can be drawn. To target SCD related pain in children, a multidisciplinary approach focusing on the physical, psychological and social aspects seems most appropriate, but the clinical implementation of non-pharmacological interventions first needs further exploration.

Implementation of an Intravenous Lidocaine Guideline for Children and Adolescents with Sickle Cell Vaso-Occlusive Pain

IntroductionSickle cell disease (SCD) affects approximately 100,000 Americans.[1] Vaso-occlusive episodes (VOEs) are the leading cause of hospitalization in SCD; in 2016, out of 134,000 SCD hospitalizations, 81% included VOE. [2] Opioids are the mainstay of VOE treatment, but side effects include sedation, hyperalgesia, and dependency risk. Lidocaine, which inhibits voltage-gated sodium channels in peripheral sensory nerves, is given intravenously (IV) for postoperative pain management and holds promise for VOE treatment.[3]At St. Louis Children's Hospital (SLCH), children admitted with VOEs receive an opioid by continuous infusion plus patient-controlled analgesia (PCA) and non-opioid adjuvants. In 2019, the Sickle Cell Disease Program and Pain Management Service jointly developed a guideline for VOE management that includes:1. Standardized dosing of IV opioids and IV or oral NSAIDs2. Pain management service consultation for all children age ≥10 y admitted with VOE3. Initiation of IV lidocaine infusion (1-1.5 mg/kg/h x 48 h) within 24 h of admission for severe pain4. Addition of non opioid adjuvants, such as muscle relaxants, topical agents, and agents for neuropathic pain5. IV lidocaine is prescribed by the Pain Management Service. Patients are monitored for lidocaine side effects including tinnitus, perioral tingling, vital sign changes, and seizures. A 24 h serum lidocaine level is drawn to ensure levels are not supra-therapeutic.We aimed to evaluate the implementation of this care guideline, focused on IV lidocaine as a safe, tolerable and effective adjunct to opioids for VOE treatment in children.MethodsThis retrospective cohort study reviewed records of children with SCD age ≥10 years admitted for VOE at SLCH during 2018-2020. Data collected included patient demographics, impact on pain, lidocaine levels, and reported side effects. This study was approved by the institutional review board.ResultsWe identified 61 patients (31 males), median age 15.7 y (range 9-21), with 174 IV lidocaine administrations during 164 hospitalizations. Hemoglobin (Hb) SS comprised 60.7% of the cohort; 32.8% had Hb SC disease, 4.9% had Hb Sβ0 thalassemia and 1.6% had Hb Sβ+ thalassemia. IV lidocaine was started within 24 h for 78.7% (129/164) of included admissions. The mean blood lidocaine level was 2.14 mcg/ml (SD 1.23). Of the 164 admissions, 9 individuals had lidocaine levels above the limit of 4.5 mcg/ml, none had symptoms of toxicity. Few side effects were noted: lip paresthesia in 1 child (lidocaine stopped, but received in future admissions); nausea in 1 child (declined lidocaine in future admissions); pain increase in 1 teen (lidocaine was stopped). One child stopped lidocaine infusions prematurely during 2 admissions due to refusal of phlebotomy for the lidocaine level. Overall, 59 children perceived benefit of IV lidocaine and chose to receive it again during later admissions. During 10 prolonged hospitalizations, a second 48-hour lidocaine infusion was given due to patient reported benefit.We identified falsely elevated lidocaine levels when subcutaneous lidocaine was used before phlebotomy, but no patients with high lidocaine levels experienced toxicity. We altered our response to supratherapeutic levels by pausing the lidocaine infusion, redrawing lab at a peripheral site without subcutaneous lidocaine contamination, and resuming lidocaine infusion if level was normal. Every repeated lidocaine level was within normal limits.DiscussionIn our cohort, IV lidocaine was safe, tolerable, and improved pain control. The care guideline was initiated within 24 hours for 78.7% of admissions. Mild side effects occurred in only 3 patients, highlighting safety. Future considerations include a prospective study focused on length of stay, patient-reported outcomes, opioid exposure, and factors influencing the care guideline's utilization.

Nogo-a Pathway Contributes to Neural Injury and Pain in Sickle Cell Disease

Sickle cell disease (SCD) is characterized by chronic pain and bouts of extreme acute pain from vasoocclusive crises (VOC). Sickle pain has both neuropathic and inflammatory features (Tran et al., Blood 2017). Mechanisms underlying neural injury remain unknown in SCD. Neurite outgrowth inhibitor (NOGO-A/reticulon-4) and its receptor NGR1 contribute to pain, neuronal damage, and inhibition of neurite outgrowth (Hu et al., FASEB J 2019). We examined if NOGO-A pathway is activated in a sickle microenvironment and if its inhibition will ameliorate hyperalgesia in BERK sickle mice. We used Rho kinase activity (ROCK) downstream of NGR1 as a readout of activation of NOGO-A/NGR1 pathway. We observed increased expression of NOGO-A (~260%, p<0.05) and NGR1 (~180%, p<0.05) in the dorsal root ganglia, and increased NOGO-A and ROCK activity in spinal cords of sickle mice compared to control mice expressing normal human hemoglobin A. Earlier, we found that an endogenous cannabinoid, palmitoylethanolamide (PEA) inhibits spinal NOGO-A expression and ROCK activity in sickle mice (Argueta et al., ASH 2020 #225). We hypothesized that sickle microenvironment with cell-free heme and inflammation activates NOGO-A/NGR1-ROCK pathway leading to nerve injury and pain, and inhibition of this pathway will ameliorate hyperalgesia in sickle mice.Using terminally differentiated rat pheochromocytoma (PC12) cells, we simulated a sickle microenvironment with hemin (40 µM) and TNFα (1 ng/ml) (H+T). H+T elevated ROCK activity compared to vehicle (~40%, p<0.05). PEA (30 uM) and 2 µM NEP (1-40), a competitive antagonist of NGR1, attenuated H+T-induced ROCK activity (both p<0.01); co-treatment had no additive effect, indicating a common pathway. As well, siRNA (10 nM) knockdown of NGR1 reversed H+T-induced ROCK activity (p<0.001), which was equally effective with 30 µM PEA co-treatment. Functionally, treatment with 30 µM PEA or 2 µM NEP (1-40) enhanced neurite outgrowth in H+T-treated PC-12 cells (~120%, p<0.001). NEP (1-40) at 5 mg/kg reduced mechanical and cold (both ~50%, p<0.001) hyperalgesia in sickle mice compared to baseline (BL) and/or vehicle treatment. Together, these data demonstrate that NOGO-A/NGR1 pathway activation may underlie nerve injury, and inhibition of this pathway with a NGR1 antagonist or PEA promotes neurite outgrowth and reduces hyperalgesia in a sickle microenvironment.We next examined the contribution of exogenously administered and endogenously produced PEA in ameliorating hyperalgesia. Mass spectrometry revealed that spinal PEA is reduced in female (p<0.05) and male (p<0.001) sickle mice compared to age/sex-matched control mice. Exogenous PEA (i.p. 20 mg/kg/d) reduced cold avoidance over a 3-day treatment period, showing significantly more time in the cold chamber compared to BL or vehicle at 1 h, 24 h, and 72 h (p<0.05). The analgesic effect of PEA was maintained for 9 days of treatment without developing tolerance. We next increased endogenous PEA by inhibiting its degradative enzyme, N-acylethanolamine acid amidase, with ARN19702 (i.p. 3, 10, & 30 mg/kg/d), which reduced mechanical (~50%, p<0.001) and cold hyperalgesia (~40%, p<0.001) over 72 hours in a dose-dependent manner. Since hypoxia and ischemia reperfusion injury contribute to acute VOC pain, we incited hypoxia-reoxygenation (HR; 3 h @ 8% O 2, 92% N 2, followed by 1 h @ normoxia) to simulate acute VOC pain. We observed that 5-day pretreatment with PEA (i.p. 20 mg/kg/d) before HR prevented mechanical and cold hyperalgesia following HR in sickle mice. Moreover, treatment with PEA after HR incitement significantly reduced hyperalgesia for 24 h after HR compared to BL (~30%, p<0.001) and vehicle treated (~66%, p<0.001) sickle mice.NGR1 antagonism reduces spinal microglial injury/activation. Heme and TNFα have been shown to cause microglial injury in vitro, while spinal microglial activation has been demonstrated in sickle mice (Lei et al., Antioxid Redox Signal 2021). Thus, NGR1/ROCK cascade may contribute to both neuronal injury and inflammation in the central nervous system leading to neuropathic pain. Our data suggest that PEA and targeting NOGO-A pathway may prevent/reduce chronic and acute hyperalgesia in sickle mice. We speculate that interventions targeting NOGO-A pathway may prevent/reduce neuropathic pain and that PEA has the translational potential for the treatment of chronic and acute pain in SCD. DisclosuresGupta: Tautona Group: Consultancy, Honoraria; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; 1910 Genetics: Other: Grantee; Grifols: Other: Grantee; SCDAA: Membership on an entity's Board of Directors or advisory committees; CSL Behring LLC: Honoraria; NIH: Other: Grantee; University of Minnestoa Foundation: Other: Philanthropic Funding; Southern California Institute for Research and Education Foundation: Other: Philanthropic Funding; Cyclerion: Research Funding; UCI Foundation: Other: Philanthropic Funding.

A Resident-Led Quality Improvement Initiative to Optimize Care for Children and Young Adults with Sickle Cell Disease Vaso-Occlusive Pain with Intranasal Fentanyl in the Emergency Department

Background:Sickle cell disease (SCD) is an inherited blood condition that predisposes affected patients to severe vaso-occlusive (VOC) pain events. The NHLBI (last revised in 2014) and ASH guidelines (last revised 2020) recommend a door-to-first dose should be within 60 minutes vs. 30 minutes from registration, and reassessment and re-administration of medications should be every 30 minutes. Non-IV routes of administration, i.e. intranasal (IN) can facilitate rapid analgesic treatment. Recent studies have shown IN Fentanyl as an effective pharmacological strategy to treat vaso-occlusive pain episodes.Methods:This resident-led Quality Improvement specific aim was to reduce the meantime from check-in to first analgesic delivery to SCD patients with VOC presenting to the Pediatric Emergency Department (PED) by at least 20% during 12 months and to improve the overall care of SCD VOC in accordance to best practices.PDSA cycle methodology was utilized to identify root causes, countermeasures, and key drivers (Figure 1A). We implemented a SCD VOC clinical pathway for PED providers to utilize our enhanced and updated version of an electronic order set named “PED Sickle Cell Crisis Power Plan” that includes IN Fentanyl as first-line therapy for SCD VOC. IRB approval was obtained.PED nursing staff was trained to administer IN Fentanyl with a nasal mucosa atomizer. Exclusion criteria of patients with SCD with other ICD-10 diagnosis codes, i.e pain not associated with VOC. The main indicators were assessment-to-dose time; registration-to-discharge time; first dose-to-discharge time, and rate of VOC admissions. Data was collected by discrete-time stamps and statistically analyzed using Excel 365. The analysis compared baseline with initial PDSA cycles from December 2019 to February 2020, and from September 2020 to March 2021.Results:From September 2020 to February 2021, a total of 54 encounters for SCD VOC qualified clinically to receive IN Fentanyl. A total of 49 of these encounters received this medication, while 5 refused its administration.Patient demographics: Male-to-female ratio was 53% and 47%, respectively. The majority of the patients seen were adolescents (63% with ages between 12-21 years). African-American participants represented 88% and non-Hispanics 84%.After our interventions, 94% of encounters have documented pain reassessment in their electronic medical records. IN Fentanyl was first introduced in the PED in September 2020, and became the first medication to be administered in 94% of the encounters. The average length of stay in the PED was 269 minutes (4 hrs. with 29 minutes).The SCD VOC Clinical Pathway was used in 90% of the encounters and the SCD VOC Power Plan was used in 80% of them. From the total of encounters, 59% required admission to the floor for further pain management strategies.As shown in the control chart (Figure 1.B), the meantime from check-in to first analgesic delivery to patients with VOC presenting to the PED was reduced to under 40 minutes by February 2021.After the implementation of IN Fentanyl, there is an overall improvement of the waiting time for administration of medications of more than 70 minutes (from 138 min down to 67 minutes). Most importantly, 37% (18/49) of SCD VOC events were discharged after successful VOC pain management in the PED.Discussion:PED staff surveys demonstrated a lack of familiarity with current VOC guidelines and a standardized pathway. Medication refusal of IN Fentanyl was found to be related mostly to patient preference, poor knowledge about side effects, and parental fear for oversedation before our interventions.Conclusion:A multi-disciplinary team was formed to assist health care providers in the ED to deliver optimal care to patients with SCD based on the current evidence-based SCD VOC clinical pathway and efficient pharmacological intervention with IN Fentanyl.Standardized procedures to treat and reassess pain for SCD VOC patients in the PED resulted in check-in to first-dose time reduction by 47%. There was a consistent improvement in Length of Stay in the PED, which decreased more than 60 minutes (from 5 hrs. 21 min. to 4 hrs. 29 min).There is a significant improvement of quality in the care of VOC including 1. Pain scoring system. 2. Documented pain reassessment. 3. Use of a multidisciplinary reviewed protocol that includes PED SCD VOC clinical pathway, and an updated order set power plan with IN Fentanyl as the first line. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Impact of Early Analgesia on Hospitalization for Sickle Cell Pain Crisis

National Institutes of Health guidelines for management of sickle cell acute pain suggests the use of an individualized prescribing protocol to improve outcomes for patients suffering from acute pain. The evidence that individualized pain plans improve clinical outcomes is limited and the recommendation is based on consensus opinion. Prior to implementing individualized inpatient SCD pain plans, we sought to evaluate the time required to achieve maximum opioid dose without individualized prescribing protocols and its negative impact on length of stay.Methods: We conducted an 18-month retrospective cohort study of all SCD pediatric patients admitted from the Emergency Department (ED) for SCD pain. We recorded the ED admission time, order entry time for the maximum opioid dose (mg) during the hospitalization, time that maximum opioid dose was delivered, and time of discharge orders. Maximum opioid dose was defined as total hourly cumulative dose received in oral morphine equivalents. The primary endpoint was time (hours) required to achieve maximum opioid dosage. Secondary endpoints included: total inpatient hours, hours until discharge after a maximum opioid dose had been reached, and the impact of current SCD modifying therapy (hydroxyurea, transfusion, both, or none). Since we plan to first pilot individualized pain plans in patients with recurrent pain events, we a priori defined patients with repeated pain events as those with ≥3 pain admissions during an 18-month period. A priori we dichotomized achievement of maximum opioid dose as “early” (maximum opioid dose ordered within 24 hours from admission) or “late” (ordered >24 hours from admission). Each pain admission was considered an independent event. We performed descriptive statistics, t-test or Wilcoxon for continuous variables, and Fisher's exact test or Chi-squared test for categorical variables, using JMP Pro 12 (Cary, NC).Results: We identified 179 pain admission events among 92 participants over 18 months (range: 1 to 9 events/patient). Data revealed 50% (n=90) admission events occurred in females. The mean age for these admission events was 13.5 years (range: 0.5-19). Genotypes included: HbSS or HbSB0 thalassemia (n=68 (74%)), HbSC (n=21 (23%)), HbSB+ thalassemia (n=3 (3%)). SCD modifying therapy categories included: 97 (54%) participants prescribed hydroxyurea (HU), 23 (13%) receiving transfusion therapy, 11 (6%) receiving transfusion and prescribed HU, and 48 (27%) no SCD therapy. The mean time elapsed until the order for the maximum total daily opioid dose was entered was 24 (SD 42) hours and the mean time until the maximum opioid dose was delivered was 37.3 (SD 48.9) hours. The mean time to maximum opioid order was similar among SCD modifying therapy categories (p=0.3). The mean total hospitalization time was 101 hours (range: 15-455 hours). There was no statistical difference in mean total hospitalization time based on current SCD modifying therapy (p=0.4).We identified 91 admission events among 19 participants that required repeat pain admissions. Participants with repeat pain admission events required more time to achieve a maximum opioid dose than those with two or less pain admissions (31.1 vs 17.5 hours, p=0.03) despite having non-significant differences in time to discharge after the maximum opioid dose was ordered (82.5 vs 70.0 hours, p=0.2). Among repeat admission participants, 60 events (66%) were categorized as “early” achievement of a maximum opioid dose and 31 (34%) were categorized as “late.” Participants with “early” maximum opioid orders had significantly shorter length of total hospital stay (early: 78±54 vs late: 183±96 hours, p<0.0001) as well as shorter time to discharge after that maximum order was placed (early: 71±52 vs late: 105±69 hours, p=0.01). Current SCD therapies did not have an impact on time to maximum opioid order (p=0.4) or total hospital stay (p=0.2).Conclusion: It is important to quickly achieve appropriate analgesia for pediatric SCD patients suffering with pain. Participants with frequent pain admissions that achieved earlier analgesia, as determined by maximum opioid dose within 24 hours, required shorter hospitalizations than patients that required longer titration to maximum opioid dose. Individualized pain plans should be prospectively evaluated to determine their impact on early achievement of analgesia and decreasing hospitalization length of stay. DisclosuresLebensburger:ASH: Research Funding; NHLBI: Research Funding.

The Abnormal Presence of Mitochondria in Circulating Red Blood Cells Cause an Increased Oxygen Consumption Rate, ROS Generation and Hemolysis in Patients with Sickle Cell Disease

Sickle Cell Disease (SCD) is an inherited blood disorder that affects millions of people worldwide, and it is caused by a mutation of the β-globin gene which results in the polymerization of HbS when deoxygenated. Patients with sickle cell disease experience severe pain, multi organ damage, and shortened life span. Changes arising from sickle hemoglobin (HbS) inside the red blood cell (RBC) leads to an imbalance of the oxidative reactions which increases reactive oxygen species (ROS) generation. ROS causes hemolysis and damages blood vessels. Previously, our lab demonstrated that SCD patients have a significant fraction of mitochondria retaining-RBCs which were associated with excessive levels of ROS. In addition immature mitochondria containing reticulocytes, R1 reticulocytes, are increased in the peripheral blood of SCD patients compared to control subjects. Here we report that the percentage of mitochondria retaining-RBCs directly correlated with the absolute number of reticulocytes (n=18,r=0.69, P< 0.001). As would be expected we were able to link mitochondria-retention with hemolysis. In addition, when we investigated energy metabolism we made the novel finding that SCD RBCs have an increased oxygen consumption rate (OCR). Mitochondrial-RBC retention and markers of hemolysis (serum bilirubin, and LDH) were compared by using Pearson's correlation coefficient analysis. The total serum bilirubin was directly associated with the percentage of mitochondria-containing RBCs in SCD patients' blood samples (r=0.31, n=41, p<0.04). A subgroup analysis showed a strong association between bilirubin and mitochondria-retaining RBCs in SCD patients who were not taking Hydroxyurea (r=0.55, n=17, P<0.02). Lactate dehydrogenase (LDH) is a known biomarker for hemolysis-and associated disease complications and early mortality in patients with SCD. There was a less significant association of percentage of mitochondria- retaining RBCs in SCD with serum LDH (r=0.02, n=40, P<0.2) when all patients were analyzed, however, a strong association was seen with serum LDH and mitochondria retaining RBCs in SCD patients who were not taking Hydroxyurea (r=0.67, n=17, P<0.002). We further investigated the mitochondrial RBCs energy metabolism in SCD as compared to controls in both human and mice. RBCs obtained from Townes SCD or control mice were seeded in an Agilent Seahorse XF 24-well plate using the Seahorse XF Base Medium with supplements, and we monitored the OCR and extracellular acidification rate (ECAR), in real time by Seahorse XFe-extracellular flux analyzer. OCR(pmol/min) standardized for protein was significantly higher in sickle cell RBCs of both human and mice origin compared to control. [((SCD patients(Hb SS): 6.92± 1.23, n=2 and control subjects (Hb AA)2.55±0.17, n=2, p<0.006)). ((Townes SCD (HbSS): 169.3± 30.8, n=3 and Transgenic control (HbAA):5.0±0.8, n=2, p<0.001))]. OCR was reduced to normal levels with oligomycin which is a known blocker of mitochondrial respiration. ECAR, a measure of glycolysis, was significantly higher levels in SCD patient and mouse samples compared to control. These findings support our premise that mitochondria retaining RBCs play a role in intravascular hemolysis. In addition, they indicate that RBC from SCD patients have increased oxygen consumption. Mitochondrial retention in RBCs have two possible mechanism of damage to the RBC, increased ROS formation and increased deoxygenated HbS polymer formation due to mitochondrial oxygen consumption. These results support further investigation into the role of mitochondrial energy metabolism in the pathogenesis of sickle cell disease. DisclosuresNo relevant conflicts of interest to declare.