Diagnosis and Treatment of Spontaneous Intracranial Hypotension: Role of Epidural Blood Patching

Purpose of Review

This review focuses on the challenges of diagnosing and treating spontaneous intracranial hypotension (SIH), a condition caused by spinal CSF leakage. It emphasizes the need for increased awareness and advocates for early and thoughtful use of empirical epidural blood patches (EBPs) in suspected cases.

Recent Findings

SIH diagnosis is hindered by variable symptoms and inconsistent imaging results, including normal brain MRI and unreliable spinal opening pressures. It is crucial to consider SIH in differential diagnoses, especially in patients with connective tissue disorders. Early EBP intervention is shown to improve outcomes.

Summary

SIH remains underdiagnosed and undertreated, requiring heightened awareness and understanding. This review promotes proactive EBP use in managing suspected SIH and calls for continued research to advance diagnostic and treatment methods, emphasizing the need for innovative imaging techniques for accurate diagnosis and timely intervention.

Impact of Spinal CSF Leaks on Quality of Life and Mental Health and Long-Term Reversal by Surgical Closure

Background and Objectives

Spontaneous intracranial hypotension (SIH) caused by a spinal CSF leak is a multisymptom syndrome, which can dramatically affect physical and mental health. However, systematic data on health-related quality of life (HRQoL) and mental health are scarce. We hypothesized that surgical treatment leads to significant and sustained improvements in HRQoL and mental health in patients with SIH.

Methods

In this single-center cohort study, we prospectively collected HRQoL and mental health data in patients undergoing surgical closure of a spinal CSF leak from September 2020 to November 2022. EuroQoL (EQ-5D-5L), including the health state index (EQ-Index) and the visual analog scale (EQ-VAS), measured HRQoL. The 21-item version of the Depression Anxiety Stress Scales (DASS-21) measured symptoms of mental health. Follow-ups were performed 3 and 6 months postoperatively. Primary outcome was the change in EQ-Index, EQ-VAS, and DASS-21 subscales. Secondary outcome was the impact of baseline depression symptoms on HRQoL outcomes following surgery.

Results

Seventy-four patients were included. EQ-VAS improved from 40 (interquartile range [IQR] 30-60) preoperatively to 70 (IQR 55-85) at 3 months and to 72 (IQR 60-88) at 6 months postoperatively (p < 0.001, respectively). EQ-Index increased from 0.683 (IQR 0.374-0.799) to 0.877 (0.740-0.943) at 3 months and to 0.907 (0.780-0.956) at 6 months postoperatively (p < 0.001, respectively). Depression, anxiety, and stress significantly improved after surgery. Preoperative depressive symptoms did not affect the HRQoL outcome.

Discussion

The severe impact of a spinal CSF leak on HRQoL and mental health significantly improved after closure of the leak. Higher levels of depressive symptoms do not predict worse outcomes and should not discourage invasive treatment. Further systematic evaluation of outcomes, with special regard to quality of life, is needed, as it allows a comparison of symptom burden between SIH and more familiar diseases as well as a comparison of different treatment modalities in future studies.

Progressive superficial siderosis despite complete remission of intracranial hypotension symptoms following epidural patching: Case report

Spontaneous intracranial hypotension (SIH) commonly results from ventral spinal cerebrospinal fluid (CSF) leaks and epidural patches are advocated as first-line treatment. Complications such as superficial siderosis can arise but have previously been reported only in the context of long-term persistent, ongoing, CSF leak and SIH. We report a case of a patient with SIH from a ventral spinal CSF leak that was treated with epidural patching and experienced complete resolution of SIH. Four years later SIH symptoms recurred, and brain magnetic resonance imaging unexpectedly showed the interval accumulation of hemosiderin pigmentation on the cerebellum and brainstem during the period when the patient was without symptoms of SIH. This case uniquely demonstrates the progression of superficial siderosis despite the apparent resolution of SIH. Our findings suggest two divergent pathophysiological outcomes from spinal ventral dural tear: (1) CSF loss causing SIH; and (2) persistent low-level bleeding arising from the spinal dural tear leading to superficial siderosis. These divergent pathophysiologies had a discordant response to epidural patching. Epidural patching successfully treated the SIH but did not prevent the progression of superficial siderosis, indicating that some patients may require more than epidural patching despite symptom resolution. This case highlights the need for post-treatment monitoring protocols in patients with ventral spinal CSF leaks and SIH and raises important questions about the adequacy of epidural patching in certain SIH cases arising from ventral spinal CSF leak.

Intestinal energy harvest is associated with post-bariatric surgery weight loss

Background/Objectives

Metabolic and bariatric surgery (MBS) is the most effective treatment for severe obesity; however, a significant subset of patients does not achieve expected weight loss or have substantial weight recurrence over time. The intestinal energy harvest is a potential determinant of varying weight loss outcomes, but with limited exploration. We assess the relationships between diet, intestinal energy harvest, and weight outcomes over 24 months in individuals who have undergone MBS.

Subjects/Methods

Calorie absorption was assessed with bomb calorimetry and dietary questionnaires before and after MBS. Within a total of 67 patients, fecal energy density was measured in 67, 56, 60, 67, 44, 47 samples at 0, 1, 6, 12, 18, and 24 months, respectively. Multivariate regression was developed to identify potential weight loss predictors, and random forest algorithms were employed to forecast weight results based on intestinal energy harvest.

Results

Intestinal energy harvest enhanced the predictability of patient weight loss outcomes with random forest models. A notable difference in relative fecal energy content was observed between patients experiencing optimal and sub-optimal weight loss (p<0.01). Prior to MBS, an increased energy content in feces (indicating less energy absorption) is associated with greater weight loss after the operation. Associations between diet and energy harvest were insignificant.

Conclusion

MBS changes energy harvest capacity post-surgery. A higher relative fecal energy content (lower energy absorption) at one month correlates with better weight loss outcomes at 6M, 12M, 18M and 24M post-MBS. Findings may guide the development of diagnostic tools and treatment guidelines for patients at risk of suboptimal weight loss outcomes.

CLINICAL TRIAL REGISTRATION

The trial is registered at clinicaltrials.gov (NCT03065426).

Examining sex differences in the association between sedentary behavior and cognitive function in bariatric surgery patients

BACKGROUND

Obesity is associated with cognitive impairment. A potential contributor to these deficits is sedentary behavior (SB), which is linked to poorer cognitive functioning in other populations. Little is known about the association between SB and cognitive function in bariatric surgery populations.

OBJECTIVES

This cross-sectional study examined the association between SB and cognitive function in preoperative bariatric surgery patients, as well as possible sex differences in this relationship.

SETTING

Data were collected at 2 health centers in the United States.

METHODS

A total of 121 participants (43.2 ± 10.3 yr of age) scheduled for Roux-en-Y gastric bypass or sleeve gastrectomy completed the National Institute of Health (NIH) Toolbox for the Assessment of Neurological and Behavioral Function Cognition Domain, a computerized neuropsychological assessment battery. Participants wore a waist-mounted accelerometer for 7 consecutive days to measure SB and light-intensity physical activity (LPA).

RESULTS

Pearson and partial correlations found no significant relationships between cognitive function and SB or LPA in the full sample. However, partial correlations controlling for LPA found that greater SB was associated with poorer performance on List Sorting Working Memory Test in women (r = -.28; P = .006), whereas there was a positive relationship between SB and Dimensional Change Card Sort for men (r = .51; P = .015; 95% CI [.25, .73]).

CONCLUSIONS

These results showed that greater SB, independent of LPA, is associated with poorer working memory in women and better set shifting ability in men. Future studies should examine the possibility of domain-specific cognitive effects associated with SB in bariatric surgery samples and clarify possible sex differences.

Human ventromedial prefrontal cortex lesions enhance the effect of expectations on pain perception

Pain is strongly modulated by expectations and beliefs. Across species, subregions of ventromedial prefrontal cortex (VMPFC) are implicated in a variety of functions germane to pain, predictions, and learning. Human fMRI studies show that VMPFC activity tracks expectations about pain and mediates expectancy effects on pain-related activity in other brain regions. Prior lesion studies suggest that VMPFC may instead play a more general role in generating affective responses to painful stimuli. To test whether VMPFC is required to generate affective responses to pain or is more specifically involved in expectancy-based pain modulation, we studied responses to heat stimuli in five adults with bilateral surgical lesions of VMPFC and twenty healthy adults without brain damage. All participants underwent a quantitative sensory testing procedure followed by a pain expectancy task in which cues predicting either low or high pain were followed by intermittent medium intensity heat stimuli. Compared to adults without brain damage, individuals with VMPFC lesions reported larger differences in expected pain based on predictive cues and failed to update expectations following the covert introduction of unexpected medium temperature stimuli. Consistent with observed expectancy differences, subjective pain unpleasantness ratings in the VMPFC lesion group were more strongly modulated by cue during thermal stimulation. We found no group differences in overall pain sensitivity, nor in relationships between pain and autonomic arousal, suggesting that VMPFC damage specifically enhances the effect of expectations on pain processing, likely driven by impaired integration of new sensory feedback to update expectations about pain. These results provide essential new data regarding the specific functional contribution of VMPFC to pain modulation.

Postoperative opioid prescribing patients with diabetes: Opportunities for personalized pain management

BACKGROUND

Opioids are commonly prescribed for postoperative pain, but may lead to prolonged use and addiction. Diabetes impairs nerve function, complicates pain management, and makes opioid prescribing particularly challenging.

METHODS

This retrospective observational study included a cohort of postoperative patients from a multisite academic health system to assess the relationship between diabetes, pain, and prolonged opioid use (POU), 2008-2019. POU was defined as a new opioid prescription 3-6 months after discharge. The odds that a patient had POU was assessed using multivariate logistic regression controlling for patient factors (e.g., demographic and clinical factors, as well as prior pain and opiate use).

FINDINGS

A total of 43,654 patients were included, 12.4% with diabetes. Patients with diabetes had higher preoperative pain scores (2.1 vs 1.9, p<0.001) and lower opioid naïve rates (58.7% vs 68.6%, p<0.001). Following surgery, patients with diabetes had higher rates of POU (17.7% vs 12.7%, p<0.001) despite receiving similar opioid prescriptions at discharge. Patients with Type I diabetes were more likely to have POU compared to other patients (Odds Ratio [OR]: 2.22; 95% Confidence Interval [CI]:1.69-2.90 and OR:1.44, CI: 1.33-1.56, respectively).

INTERPRETATION

In conclusion, surgical patients with diabetes are at increased risk for POU even after controlling for likely covariates, yet they receive similar postoperative opiate therapy. The results suggest a more tailored approach to diabetic postoperative pain management is warranted.

Prediction of opioid-related outcomes in a medicaid surgical population: Evidence to guide postoperative opiate therapy and monitoring

BACKGROUND

Treatment of surgical pain is a common reason for opioid prescriptions. Being able to predict which patients are at risk for opioid abuse, dependence, and overdose (opioid-related adverse outcomes [OR-AE]) could help physicians make safer prescription decisions. We aimed to develop a machine-learning algorithm to predict the risk of OR-AE following surgery using Medicaid data with external validation across states.

METHODS

Five machine learning models were developed and validated across seven US states (90-10 data split). The model output was the risk of OR-AE 6-months following surgery. The models were evaluated using standard metrics and area under the receiver operating characteristic curve (AUC) was used for model comparison. We assessed calibration for the top performing model and generated bootstrap estimations for standard deviations. Decision curves were generated for the top-performing model and logistic regression.

RESULTS

We evaluated 96,974 surgical patients aged 15 and 64. During the 6-month period following surgery, 10,464 (10.8%) patients had an OR-AE. Outcome rates were significantly higher for patients with depression (17.5%), diabetes (13.1%) or obesity (11.1%). The random forest model achieved the best predictive performance (AUC: 0.877; F1-score: 0.57; recall: 0.69; precision:0.48). An opioid disorder diagnosis prior to surgery was the most important feature for the model, which was well calibrated and had good discrimination.

CONCLUSIONS

A machine learning models to predict risk of OR-AE following surgery performed well in external validation. This work could be used to assist pain management following surgery for Medicaid beneficiaries and supports a precision medicine approach to opioid prescribing.

Relationship of Bern Score, Spinal Elastance, and Opening Pressure in Patients With Spontaneous Intracranial Hypotension

BACKGROUND AND OBJECTIVES

Existing tools to diagnose spontaneous intracranial hypotension (SIH), namely spinal opening pressure (OP) and brain MRI, have limited sensitivity. We investigated whether evaluation of brain MRI using the Bern Score, combined with calculated craniospinal elastance, would aid in diagnosing SIH and provide insight into its pathophysiology.

METHODS

A retrospective chart review was performed of patients who underwent brain MRI and pressure-augmented dynamic CT myelography (dCTM) for suspicion of SIH. Two blinded Neuroradiologists assigned Bern Scores for each brain MRI. OP and incremental pressure changes after intrathecal saline infusion were recorded to calculate craniospinal elastance. The relationship between Bern Score, OP, elastance, and whether a leak was found were analyzed.

RESULTS

72 consecutive dCTMs were performed in 53 patients. 12 CSF-venous fistulae, two ruptured meningeal diverticula, two dural defects, and one dural bleb were found (17/53=32%). Among patients with imaging proven CSF leak/fistula, OP was normal in all but one patient, and was not significantly different in those with a leak compared to those without (15.1 vs 13.6 cm H2O, p = 0.24, A=0.40). Average Bern Score in individuals with a leak was significantly higher than in those without (5.35 vs 1.85, p < 0.001, A=0.85), even when excluding pachymeningeal enhancement from the score (3.77 vs 1.57, p = 0.001, A=0.78). Average elastance in those with a leak was higher than in those without, but this difference was not statistically significant (2.05 vs 1.20 mL/cm H2O, p = 0.19, A=0.40). Increased elastance was significantly associated with an increased Bern Score (p < 0.01, 95% CI -0.55, 0.12), and was significantly associated with venous distention, pachymeningeal enhancement, prepontine narrowing, and subdural collections, but not a narrowed mamillopontine or suprasellar distance.

DISCUSSION

OP is not an effective predictor for diagnosing CSF leak, and if used in isolation would result in misdiagnosis of 94% of patients in our cohort. The Bern Score was associated with a higher diagnostic yield of dCTM. Elastance was significantly associated with certain components of the Bern Score.

In Search of a Durable Dural Patch

Cerebrospinal fluid (CSF) leaks are a cause of severe chronic headache, often accompanied by neck pain, hearing alterations, tinnitus, vertigo, nausea, difficulty with memory or concentration, and fatigue. When chronic, CSF leaks often appear quite different from acute post–dural puncture headaches. Most importantly, the orthostatic nature of the headache is less prominent. The varied presentation between acute and chronic CSF leaks, and low awareness for their ability to occur atraumatically and in the absence of a dural puncture, creates the opportunity for CSF leaks to evade diagnosis—typically for years before being accurately diagnosed. While an acute CSF leak typically presents as a severe orthostatic headache, chronic CSF leak may present as a second-half of the day headache, exertional headache, non-orthostatic chronic daily headache, thunderclap headache, or even a reverse orthostatic headache. The combination of severe head pain and nausea may cause the patient to be diagnosed with chronic migraine. Yet patients with CSF leaks can benefit from, and even find total resolution with, epidural blood patching or surgery. In this chapter we explore the case of a patient presenting with a chronic CSF leak characterized by persistent headaches, nausea and vomiting, and tachycardia following an unintended dural puncture.

Racial Microaggressions and Anti-Racism: A Review of the Literature with Implications for School-Based Interventions and School Psychologists

Many racial-ethnic minoritized individuals are repeatedly exposed to subtle actions reflecting racial slights, termed racial microaggressions (RMAs), which are associated with adjustment problems in early adult and adult populations. Early adolescence represents a unique developmental period when minoritized youth begin their racial-ethnic identity exploration and are subjected to stereotypes and prejudice, thereby making them vulnerable to RMAs. Based upon the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist, a systematic literature search, screening and review of RMA literature focusing on high schoolers and younger youth was conducted and yielded 54 publications. This paper reviewed the publications and identified gaps in the field such as the need for systematic research on early adolescents including the frequency and severity of RMAs and the important contributions of peers, parents and teachers for RMA victims, and the need for more evidence-based programming for middle schoolers. Findings suggest that developing school-based microaggression anti-racism programs is clearly needed for minoritized and White youth.

309 A FRAILTY CENSUS OF INPATIENTS AGED 65 AND OVER ADMITTED TO A MODEL 4 HOSPITAL

Background

Frailty is a risk factor for in-hospital mortality, long hospital stay and functional decline at discharge. Profiling the prevalence and level of frailty within the acute hospital setting is vital to ensure evidence-based practice and service development within the construct of frailty.

Methods

All patients aged ≥65 years and admitted to a medical or surgical inpatient setting, were screened over a 12-hour period (08:00-20:00) using validated frailty and co-morbidity scales. Age and Gender Demographics, Clinical Frailty Scale (CFS), Charlson Co-morbidity Index (CHI) and admitting specialty (Medical/Surgical) were collected. The data was fully anonymised and ethical approval was granted. Descriptive statistics were used to profile the cohort and Chi-squared tests applied for comparisons.

Results

Within a sample of 413 patients, 291(70%) were ≥65yrs. Of this cohort, 202(70%) were ≥75yrs. 207(71%) utilised in-patient medical services and 121(41%) surgical services while 37(12%) used both. The mean CFS was 6 indicating moderate frailty levels and the mean CCI score was 4 denoting moderate co-morbidity. Overall: 195(67%) had moderate-severe frailty (CSF ≥6) while 218 (75%) had moderate-severe co-morbidity (CCI Mod 3-4, Severe ≥5). Associations with age &gt;75 and frailty (p=0.001) and medical service usage and frailty (p=0.004) were established. No significant differences were observed across genders for CFS (p=0.110) and CCI (p=0.465).

Conclusion

There is a high prevalence of frailty and co-morbidity within the admitted patient cohort ≥65yrs. Overcrowding across the hospital system and higher levels of frailty and comorbidity will contribute to increased lengths of stay and the need for specialist intervention, particularly for those ≥75yrs who represented 70% of patients screened. With an increased focus on the integration of care for older adults across care transitions, there is a clear need for expansion of frailty-based services and staff training in frailty care across the hospital and community setting.

319 CAN INDEX BARTHEL SCORE AT EMERGENCY DEPARTMENT PRESENTATION PREDICT ADVERSE OUTCOMES AMONG OLDER ADULTS AT 30 DAYS AND 6 MONTHS?

Background

Frailty is acknowledged as a significant syndrome particularly in the older population. Monitoring frailty in late life aetiology and recognising the value of frailty as a marker of risk for adverse health outcomes is vital and ensures the identification of opportunities for intervention with this cohort in clinical practice. The aim of this prospective cohort study is to examine if an index Barthel Score at Emergency Department presentation predicts adverse outcomes among older adults at 30 days and 6 months.

Methods

Six-hundred and fifty older adults (≥65 years) attending a university model 4 hospital ED were recruited. Baseline evaluation included the Barthel Index. Adverse outcomes (hospital readmission or death) were recorded by a research nurse at 30 days and 6 months, blinded to Barthel score. Descriptive statistics were used to profile the population and report the incidence of adverse outcomes.

Results

At 30 days, 61 older adults had either being admitted to hospital (n=28) or died (n=33) and at 180 days a further 72 had been admitted (n=43) or died (n=29). A total of 29% (n=189) of the population had a Barthel score of ≤15 indicating moderate dependency. Of this cohort, 70% had an adverse outcome-readmitted or died within 180 days.

Conclusion

It may be worth looking at introducing the Barthel Index as a routine measure of activity for older adults presenting to the ED. This tool demonstrates an increased risk of adverse outcomes among older adults who present with moderate dependency. Early intervention either in the hospital or community setting with this ‘at risk’ cohort may serve to reduce adverse outcomes among this group.

265 A PHYSIOTHERAPY-LED TRANSITION TO HOME INTERVENTION FOR OLDER ADULTS FOLLOWING EMERGENCY DEPARTMENT DISCHARGE: A PILOT FEASIBILITY RANDOMISED-CONTROLLED TRIAL

Background

Older adults frequently attend the Emergency Department (ED) and experience high rates of adverse outcomes following ED presentation including functional decline, ED re-presentation and unplanned hospital admission. The development of effective interventions to prevent such outcomes is a key priority for research and service provision. A presentation to an ED can be viewed as an opportunity to assess those at risk of adverse outcomes and initiate a care plan in those deemed as ‘high risk'. Our aim was to evaluate the feasibility of a physiotherapy led integrated care intervention for older adults discharged from the ED (ED-PLUS).

Methods

Older adults presenting to the ED with undifferentiated medical complaints and discharged within 72 hours were computer randomised in a ratio of 1:1:1 to deliver usual care, Comprehensive Geriatric Assessment (CGA) in the ED, or ED-PLUS (Trial registration: NCT04983602). ED-PLUS is an evidence-based and stakeholder-informed intervention to bridge the care transition between the ED and community by initiating a CGA in the ED and implementing a six-week, multi-component, self-management programme in the patient’s own home. Feasibility (recruitment and retention rates) and acceptability of the programme were assessed quantitatively and qualitatively. Functional decline was examined post-intervention using the Barthel Index. All outcomes were assessed by a research nurse blinded to group allocation.

Results

29 participants were recruited, indicating 97% of our recruitment target. 90% of participants completed the ED-PLUS intervention. All participants expressed positive feedback about the intervention. The incidence of functional decline at 6 weeks was 10% in the ED-PLUS group versus 70-89% in the usual care and CGA-only groups.

Conclusion

High adherence and retention rates were observed among participants and preliminary findings indicate a lower incidence of functional decline in the ED-PLUS group. Recruitment challenges existed in the context of COVID-19. Data collection is ongoing for six-month outcomes.

The Gut Microbiota and Short-Chain Fatty Acids in Association With Glycemia and Adiposity in Young Adults With Type 1 Diabetes: The ACT1ON Ancillary Gut Microbiome Pilot Study

Objectives

Co-managing glycemia and adiposity is the cornerstone of cardiometabolic risk reduction among people with type 1 diabetes (T1D) but targets are often not met. The gut microbiota and microbiota-derived short-chain fatty acids (SFCA) influence glycemia and adiposity but have not been sufficiently investigated in longstanding T1D. We hypothesized that an increased abundance of SCFA-producing gut microbes, fecal SCFA, and gut microbial diversity were associated with improved glycemia but increased adiposity among young adults with longstanding T1D.

Methods

Participants provided stool samples at up to four time points. 16S rRNA gene sequencing determined the abundance of SCFA-producing gut microbes. Gas-chromatography mass-spectrometry determined total and specific SCFA (acetate, butyrate, and propionate). Dual-energy x-ray absorptiometry (% body fat or lean mass) and anthropometrics (body mass index [BMI]) measured adiposity. Continuous glucose monitoring (time in range [70–180 mg/dl], above range [>180 mg/dl], and below range [54–69 mg/dl]) and hemoglobin A1c assessed glycemia. Adjusted and Bonferroni-corrected generalized estimating equations modeled the associations of SCFA-producing gut microbes, fecal SCFA, and gut microbial diversity with glycemia and adiposity. COVID-19 interrupted data collection, so models were repeated with restriction to pre-COVID visits.

Results

Data were available for up to 45 participants at 101 visits, including 40 participants at 54 visits pre-COVID. The abundance of Eubacterium hallii was associated inversely with BMI (all data). Pre-COVID, increased fecal propionate was associated with increased time above range and reduced time in target and below range; and the increased abundance of four SCFA-producing intestinal microbes (Ruminococcus gnavus, Ruminococcus 2, Eubacterium ventriosum, and Lachnospira) was associated with reduced adiposity (% body fat or BMI), of which two microbes were also associated with increased % lean mass.

Conclusions

Unexpectedly, fecal propionate was associated with detriment to glycemia, while several SCFA-producing gut microbes were associated with benefit to adiposity. Future mechanistic studies may determine whether these associations have causal linkages in T1D.

Funding Sources

National Institute of Diabetes and Digestive and Kidney Diseases.

Associations of Diet With the Intestinal Microbiota and Short-Chain Fatty Acids Among Young Adults With Type 1 Diabetes: The ACT1ON Ancillary Gut Microbiome Pilot Study

Objectives

Diet, a key component of type 1 diabetes (T1D) management, modulates the intestinal microbiota and its metabolically active byproducts, short-chain fatty acids (SCFA), via fermentation of dietary carbohydrates such as fiber. The relationships among diet, the intestinal microbiota, and SCFA have been studied proximal to T1D onset, but remain largely unexplored in longstanding T1D. We hypothesized that increased carbohydrate intake, including fiber, was associated with increased SCFA-producing microbes, fecal SCFA, and gut microbial diversity among adults with longstanding T1D and overweight or obesity.

Methods

Participants provided stool samples at up to four time points. Trained interviewers collected 24-hour dietary recalls. 16S rRNA gene sequencing determined the abundance of SCFA-producing intestinal microbes. Gas-chromatography mass-spectrometry computed total and specific fecal SCFA (acetate, butyrate, and propionate) levels. Adjusted and Bonferroni-corrected generalized estimating equations modeled the associations of dietary fiber and carbohydrate with the abundance of SCFA-producing microbes, fecal SCFA, and gut microbial diversity. Data collection was interrupted by COVID-19; therefore, analyses were repeated with restriction to pre-COVID visits.

Results

Data were available for 44 participants at 99 visits, including 42 participants with 57 visits pre-COVID. Intake of soluble fiber (all data) and available carbohydrates (pre-COVID) were inversely associated with the genus Bacteroides and Eubacterium alistipes. Pre-COVID, total and soluble fiber and available carbohydrates were positively associated with total SCFA and acetate levels, and available carbohydrates were positively associated with the genus Roseburia and Eubacterium ventriosum.

Conclusions

In our sample of young adults with longstanding T1D, increased carbohydrate intake, including fiber, was associated with both reduced and increased SCFA-producing microbes but increased total fecal SCFA and acetate, which might influence lipid metabolism and weight. Mechanistic studies may examine how a diet designed to modulate the SCFA-producing capacity of the intestinal microbiota influences metabolism and energy balance in the metabolically unique setting of T1D.

Funding Sources

National Institute of Diabetes and Digestive and Kidney Diseases.

Abstract 113: Novel Tissue Factor Inhibition For Thromboprophylaxis In COVID-19: Primary Results Of The ASPEN-COVID-19 Phase 2b Randomized Trial

Background: Tissue factor contributes to thrombo-inflammation in viral infection and may be a target in COVID-19. Recombinant nematode anticoagulant protein c2 (rNAPc2), a tissue factor inhibitor with anticoagulant, anti-inflammatory, and antiviral properties, has not been studied in COVID-19.

Methods: In Phase 2b of ASPEN-COVID-19 (NCT04655586), an open-label blinded endpoint study, COVID-19 inpatients with elevated D-dimer are randomized 1:1:2 to higher or lower dose rNAPc2 given subcutaneously up to 5 days or local standard of care heparin. Primary efficacy and safety endpoints are D-dimer change (to Day 8 or discharge if earlier) and ISTH major bleeding. Recovery time is an exploratory outcome.

Results: 160 patients were randomized at 24 sites in 3 countries. The average age was 56 years, 43% were female, 19% were Hispanic, and 21% were black. Baseline comorbidities included hypertension (51%), diabetes (35%), and smoking (35%); 11% were critically ill. On average, randomization occurred 10 days after COVID-19 symptom onset, and qualifying D-dimers were elevated 3.7-fold above the upper limit of normal. Median recovery time was 6 days (aggregate distribution shown in Figure). Enrollment has completed, database lock is anticipated Q1 2022, and final results will be ready for presentation at Vascular Discovery.

Conclusion: ASPEN tests the hypothesis that compared to heparin, rNAPc2 reduces D-dimer in COVID-19. Results may help to provide a novel therapy for thromboprophylaxis in virus-related coagulopathies.

Characteristics of Patients With Complex Limb Pain Evaluated Through an Interdisciplinary Approach Utilizing Magnetic Resonance Neurography

Patients with persistent complex limb pain represent a substantial diagnostic challenge. Physical exam, and tests such as nerve conduction, are often normal even though the patient suffers from severe pain. In 2015, we initiated a team-based approach to evaluate such patients. The approach included physicians from several specialties (Anesthesiology/Pain Medicine, Radiology, Plastic Surgery, Neurosurgery) combined with the use of advanced imaging with Magnetic Resonance Neurography (MRN). This preliminary case series discusses MRN findings identified in patients with previously difficult-to-diagnose peripheral limb pain and describes how this combination of approaches influenced our diagnosis and treatment plans. We extracted demographics, patient characteristics, presenting features, diagnostic tests performed, treatments provided, referral diagnosis and the diagnosis after interdisciplinary team evaluation from patient charts. We evaluated MRN and electrodiagnostic studies (EDX) ability to identify injured nerves. We compared abnormal findings from these diagnostics to patient reported outcome after ultrasound-guided nerve block. A total of 58 patients, 17 males and 41 females, were identified. The majority of patients presented with lower extremity pain (75%) and had prior surgery (43%). The most commonly identified abnormality on MRN was nerve signal alteration on fluid sensitive sequences, followed by caliber change and impingement. Comparing the outcome of diagnostic nerve blocks with abnormal nerve findings on MRN or EDX, we found that MRN had a sensitivity of 67% and specificity of 100% while for EDX it was 45 and 0%, respectively. After interdisciplinary discussion and imaging review, a more specific diagnosis was produced in 78% of evaluated cases opening up additional treatment pathways such as nerve-targeted surgery, which was performed in 36% cases. This descriptive case series demonstrates that a majority of patients evaluated by our team for complex limb pain were women with lower extremity pain resulting from surgery. In addition, an interdisciplinary team evaluation and the use of the moderately sensitive but highly specific MRN imaging modality resulted in a change in diagnosis for a majority of patients with complex limb pain. Future studies investigating patient outcomes after diagnosis change are currently underway based on the findings of this preliminary study.

The positive effect of malaria IPTp-SP on birthweight is mediated by gestational weight gain but modifiable by maternal carriage of enteric pathogens

BACKGROUND

Poor pregnancy and birth outcomes are common in sub-Saharan Africa and have complex aetiologies. Sulfadoxine-pyrimethamine (SP), given for intermittent preventive therapy of malaria in pregnancy (IPTp), is one of few existing interventions that improves outcomes of both mother and baby despite widespread SP-resistant malaria. Compelling evidence exists that malaria-independent pathways contribute to this protective effect, but the exact sources of non anti-malarial protection remained unknown. We hypothesized that the beneficial effect of SP on birthweight is mediated by SP activity on maternal factors, including increased gestational weight gain and antibiotic activity on pathogens in the maternal gut.

METHODS

Expectant mothers from a larger randomized control trial comparing the efficacy of IPTp-SP to IPTp with dihydroartemisinin-piperaquine (DP) were also enrolled in this sub-study study at their first antenatal care visit before commencement of IPTp (n = 105). Participants were followed monthly until delivery. Weights and mid-to-upper-arm circumferences (MUAC) were recorded. Monthly stool samples were collected and screened for five Escherichia coli pathotypes, Shigella spp., Vibrio cholerae, Salmonella, Campylobacter coli/jejuni, and three protozoa (Giardia spp., Entameba histolytica, and Cryptosporidium spp.) using previously validated molecular assays.

FINDINGS

IPTp-SP vs. IPTP-DP was associated with higher maternal gestational weight gain (GWG) and nutritional indicators (MUAC and body-mass index, BMI). GWG was found to be a mediator of the birthweight and IPTp-SP relationship, as the birthweight of SP infants, but not DP infants, varied according to maternal GWG. The burden of maternal enteric infections was high. The three most commonly observed pathogens were enteroaggregative E. coli (EAEC), atypical enteropathogenic E.coli/enterohaemorrhagic E. coli (aEPEC/EHEC), and typical enteropathogenic E.coli (tEPEC). We found that SP reduced the prevalence of EAEC in a dose-dependent manner. After 3 or more doses, SP-recipients were 90% less likely to be infected with EAEC compared to DP-recipients (ORadj = 0.07, CI95 = 0.12, 0.39, p = 0.002). Compared to DP, this coincided with higher maternal gestational weight gain (GWG) and nutritional indicators (MUAC and body-mass index, BMI). The beneficial effect of SP on maternal GWG, MUAC and BMI, was lower if SP mothers had detectable EAEC, aEPEC/EHEC, tEPEC, and LT-ETEC at baseline. Maternal EAEC and tEPEC at baseline associated with lower birthweight for babies of both SP mothers and DP mothers. When comparing IPTp regimens, the positive effect of SP on birthweight compared to DP was only observed for infants of women who did not test positive for EAEC at baseline (adjusted mean birthweight difference SP vs. DP = 156.0 g, CI95 = -18.0 g, 336.9 g, p = 0.087), though confidence intervals crossed the null.

INTERPRETATION

Our findings indicate that in pregnant Malawian women, IPTp-SP vs. IPTp-DP is consistently associated with higher MUAC, BMI, and GWG following the WHO-recommended regimen of at least 3 doses, but carriage of maternal gut pathogens before initiation of IPTp lessens this effect. Because GWG was a mediator of the association between birthweight and SP, we show that SP's previously proven positive effect on birthweight is by promoting maternal weight gain. Overall, our results present one plausible pathway SP exerts malaria-independent protection against poor birth outcomes in the context of its waning antimalarial activity and warrants further investigation.

FUNDING

A full list of funding bodies that contributed to this study can be found in the Acknowledgements section.

236 PREDICTORS OF ADVERSE OUTCOMES IN OLDER PATIENTS DISCHARGED DIRECTLY FROM THE EMERGENCY DEPARTMENT

Background

Over 40% of older patients are discharged directly from the Emergency Department (ED) and this cohort is at increased risk of adverse outcomes.

The purpose of this study was to explore the factors that predict future adverse outcomes in this cohort to inform practice, resource planning and policy.

Methods

A secondary analysis of the OPTIMEND, a single-centre, randomized-controlled trial was completed. OPTIMEND examined the effectiveness of an intervention by a team of Health and Social Care Professionals along with usual care and compared this to standard ED care alone (Dec 2018-May 2019). The inclusion criteria were adults aged 65 years and over presenting to the ED at a University Teaching Hospital with medical complaints and a Manchester Triage System category 2–5.

Results

220 patients were included (median age 79 years; 62% female). Median length of stay in ED was 5.5 hrs. 70 patients re-attended the ED within 6 months with 43 re-hospitalised within 6 months. 9 patients died within six months of discharge.

Multivariant logistic regression was completed. Age was the only independent predictor of mortality within six months of discharge {Odds Ratio (OR) 1.15, p = 0.044}. Past hospitalisation (&lt;6 months) was associated with a lower likelihood of ED re-attendance, and rehospitalization within six months of discharge (OR: 0.452 p = 0.022; OR:0.442, p = 0.046; respectively). Clinical Frailty Score was associated with a significantly higher likelihood of rehospitalization (OR:1.48, p = 0.031) but not with ED revisits (OR: 1.235, p = 0.165).

Conclusion

Older people have a high ED re-attendance rate of 33% after an index visit with 20% hospitalized subsequently. Frailty is a significant predictor of rehospitalisation. Rapid and targeted intervention for frail patients who reattend the ED should be a priority for the integrated care program to enhance admission avoidance.

Metabolite trajectories across the perinatal period and mental health: A preliminary study of tryptophan-related metabolites, bile acids and microbial composition

Depression and anxiety during pregnancy and postpartum are common, but affected women differ in timing, trajectories, and extent of symptoms. The objective of this pilot, feasibility study is to analyze trajectories of serotonin and tryptophan-related metabolites, bile acid metabolites, and microbial composition, in relation to psychiatric history and current symptoms across the perinatal period. Serum and fecal samples were collected from 30 women at three times points in the perinatal period and assayed with LC-MS/MS and 16S sequencing respectively. We defined mean trajectories for each metabolite, clustered individuals by metabolite trajectories, tested associations between metabolites, and examined metabolite levels in relation to microbial composition. Findings of note include: (1) changes in kynurenine and the ratio of kynurenic acid to kynurenine from second trimester to third trimester were strongly associated with baseline primary and secondary bile acids. (2) Secondary bile acid UDCA and its conjugated forms were associated with lower bacterial diversity and levels of Lachnospiraceae, a taxa known to produce Short Chain Fatty Acids. (3) History of anxiety was associated with UDCA levels, but history of major depression was not associated with any of the bile acids. (4) There was a trend towards lower dietary fiber for those with history of anxiety or depression. Overall, our results reveal substantial temporal variation in tryptophan-related metabolites and in bile acid metabolites over the perinatal period, with marked inter-individual variability. Trajectories of TRP -related metabolites, primary and secondary bile acids, and the absence or presence of microbes that produce Short Chain Fatty Acids (SCFAs) considered in concert have the potential to differentiate individuals based on perinatal adaptations that may impact mental and overall health.

Did she have an epidural? The long-term consequences of postdural puncture headache and the role of unintended dural puncture

OBJECTIVE

This narrative literature review examines the long-term impact of postdural puncture headache (PDPH) in postpartum women following an unintended dural puncture (UDP) with a large bore needle commonly used for epidural catheter placement. It seeks to bridge the knowledge gap for the neurologist as to the mounting body of obstetric anesthesia literature on the development of chronic headache after PDPH with this unique needle.

BACKGROUND

Headache is the most common complication of dural puncture, and the risk is greatest in the parturient population. Preexisting risk factors for this population include youth and sex, and after UDP with a large bore needle, almost 70%-80% report a headache. Additionally, there appears to be a significant cohort who experience long-term, persistent headache after UDP.

METHODS

We performed a narrative review of literature using PubMed, searching terms that included long-term follow-up after UDP with a large bore needle in the postpartum population.

RESULTS

In women who had UDP with a large bore needle used for epidural catheter placement at delivery, the rate of chronic debilitating headache is around 30% in the months following delivery and may persist for up to a year or longer.

CONCLUSION

Based on the existing literature, we have mounting evidence that UDP with the large bore needle used to place an epidural catheter should be understood as a high-risk inciting event for the development of long-term headaches not simply a high risk of acute PDPH. Additionally, consideration should be given to stratifying the etiology of PDPH, based on needle type, and recognizing the entity of chronic PDPH, thus allowing for improvements in research and diagnosis.

Cerebellar tonsillar descent: A diagnostic dilemma between Chiari malformation type 1 and spinal cerebrospinal fluid leak

Cerebellar tonsillar descent can be seen on head magnetic resonance imaging in both Chiari malformation type 1 and spinal cerebrospinal fluid leak creating the potential for misdiagnosis. We report five cases of spinal cerebrospinal fluid leak at Stanford University initially misdiagnosed and treated as Chiari malformation type 1 based on cerebellar tonsillar descent demonstrated on imaging. All five cases had sustained relief at the 6-month follow up visit from epidural blood patches for the treatment of spinal cerebrospinal leak after unsuccessful suboccipital decompression surgeries. A misdiagnosis of Chiari malformation type 1 in patients with spinal cerebrospinal fluid leak may lead to unnecessary surgeries instead of the less invasive treatment, such as epidural blood patches. It is imperative to consider a spinal cerebrospinal fluid leak in the differential based on clinical-radiological correlation and not solely on cerebellar tonsillar descent demonstrated on imaging.

Spinal cerebrospinal fluid leak in the context of pars interarticularis fracture

Background

Spinal cerebrospinal fluid (CSF) leak can lead to intracranial hypotension and is an important differential diagnosis to consider in patients with sudden-onset chronic daily headaches. Pars interarticularis (PI) fracture is a potential rare cause of suspected spinal CSF leak.

Methods

This is a retrospective case series of 6 patients with suspected spinal CSF leak evaluated between January 2016 and September 2019. All patients received a magnetic resonance imaging (MRI) of the brain with and without gadolinium, MRI whole spine and full spine computed tomography (CT) myelogram. Targeted epidural patches with fibrin sealant were performed. Treatment response at return visit (3 months post-patch) was documented.

Results

Six patients (4 females, 2 males) were diagnosed with a suspected spinal CSF leak and PI fracture. Mean age at the time of headache onset was 39 years old, and a range from 32 to 50 years old. Mean time to targeted epidural patches with fibrin sealant was 4.5 years. All 6 patients had PI fractures identified on CT myelogram and received targeted epidural patches with fibrin sealant at the site of the PI fracture. All patients had significant improvement in their headache intensity.

Conclusion

Our study highlights: 1) the importance of PI fracture as a possible culprit of suspected spinal CSF leak in patients with intracranial hypotension; 2) the added benefit of CT imaging for detecting bony abnormalities such as fractures in patients with intracranial hypotension; and 3) the successful treatment of suspected spinal CSF leak when targeting the fracture site.

Preoperative Factors Associated with Remote Postoperative Pain Resolution and Opioid Cessation in a Mixed Surgical Cohort: Post Hoc Analysis of a Perioperative Gabapentin Trial

Background

Preoperative patient-specific risk factors may elucidate the mechanisms leading to the persistence of pain and opioid use after surgery. This study aimed to determine whether similar or discordant preoperative factors were associated with the duration of postoperative pain and opioid use.

Methods

In this post hoc analysis of a randomized, double-blind, placebo-controlled trial of perioperative gabapentin vs active placebo, 410 patients aged 18–75 years, undergoing diverse operations underwent preoperative assessments of pain, opioid use, substance use, and psychosocial variables. After surgery, a modified Brief Pain Inventory was administered over the phone daily up to 3 months, weekly up to 6 months, and monthly up to 2 years after surgery. Pain and opioid cessation were defined as the first of 5 consecutive days of 0 out of 10 pain or no opioid use, respectively.

Results

Overall, 36.1%, 19.8%, and 9.5% of patients continued to report pain, and 9.5%, 2.4%, and 1.7% reported continued opioid use at 3, 6, and 12 months after surgery. Preoperative pain at the future surgical site (every 1-point increase in the Numeric Pain Rating Scale; HR 0.93; 95% CI 0.87–1.00; P=0.034), trait anxiety (every 10-point increase in the Trait Anxiety Inventory; HR 0.79; 95% CI 0.68–0.92; P=0.002), and a history of delayed recovery after injury (HR 0.62; 95% CI 0.40–0.96; P=0.034) were associated with delayed pain cessation. Preoperative opioid use (HR 0.60; 95% CI 0.39–0.92; P=0.020), elevated depressive symptoms (every 5-point increase in the Beck Depression Inventory-II score; HR 0.88; 95% CI 0.80–0.98; P=0.017), and preoperative pain outside of the surgical site (HR 0.94; 95% CI 0.89–1.00; P=0.046) were associated with delayed opioid cessation, while perioperative gabapentin promoted opioid cessation (HR 1.37; 95% CI 1.06–1.77; P=0.016).

Conclusion

Separate risk factors for prolonged post-surgical pain and opioid use indicate that preoperative risk stratification for each outcome may identify patients needing personalized care to augment universal protocols for perioperative pain management and conservative opioid prescribing to improve long-term outcomes.

Efficacy of motivational-interviewing and guided opioid tapering support for patients undergoing orthopedic surgery (MI-Opioid Taper): A prospective, assessor-blind, randomized controlled pilot trial

BACKGROUND

Postoperative opioid use can lead to chronic use and misuse. Few studies have examined effective approaches to taper postoperative opioid use while maintaining adequate analgesia.

METHODS

This randomized, assessor-blinded, pilot trial of postoperative motivational interviewing and guided opioid tapering support (MI-Opioid Taper) added to usual care (UC) enrolled patients undergoing total hip or knee arthroplasty at a single U.S. academic medical center. MI-Opioid Taper involved weekly (to seven weeks) and monthly (to one year) phone calls until patient-reported opioid cessation. Opioid tapering involved 25% weekly dose reductions. The primary feasibility outcome was study completion in the group to which participants were randomized. The primary efficacy outcome, time to baseline opioid use, was the first of five consecutive days of return to baseline preoperative dose. Intention-to-treat analysis with Cox proportional hazards regression was adjusted for operation. ClinicalTrials.gov registration: NCT02070003.

FINDINGS

From November 26, 2014, to April 27, 2018, 209 patients were screened, and 104 patients were assigned to receive MI-Opioid Taper (49 patients) or UC only (55 patients). Study completion after randomization was similar between groups (96.4%, 53 patients receiving UC, 91.8%, 45 patients receiving MI-Opioid Taper). Patients receiving MI-Opioid Taper had a 62% increase in the rate of return to baseline opioid use after surgery (HR 1.62; 95%CI 1.06-2.46; p = 0•03). No trial-related adverse events occurred.

INTERPRETATION

In patients undergoing total joint arthroplasty, MI-Opioid Taper is feasible and future research is needed to establish the efficacy of MI-Opioid Taper to promote postoperative opioid cessation.

FUNDING

National Institute on Drug Abuse.

Resolvin E1 derived from eicosapentaenoic acid prevents hyperinsulinemia and hyperglycemia in a host genetic manner

Eicosapentaenoic acid (EPA) has garnered attention after the success of the REDUCE‐IT trial, which contradicted previous conclusions on EPA for cardiovascular disease risk. Here we first investigated EPA's preventative role on hyperglycemia and hyperinsulinemia. EPA ethyl esters prevented obesity‐induced glucose intolerance, hyperinsulinemia, and hyperglycemia in C57BL/6J mice. Supporting NHANES analyses showed that fasting glucose levels of obese adults were inversely related to EPA intake. We next investigated how EPA improved murine hyperinsulinemia and hyperglycemia. EPA overturned the obesity‐driven decrement in the concentration of 18‐hydroxyeicosapentaenoic acid (18‐HEPE) in white adipose tissue and liver. Treatment of obese inbred mice with RvE1, the downstream immunoresolvant metabolite of 18‐HEPE, but not 18‐HEPE itself, reversed hyperinsulinemia and hyperglycemia through the G‐protein coupled receptor ERV1/ChemR23. To translate the findings, we determined if the effects of RvE1 were dependent on host genetics. RvE1's effects on hyperinsulinemia and hyperglycemia were divergent in diversity outbred mice that model human genetic variation. Secondary SNP analyses further confirmed extensive genetic variation in human RvE1/EPA‐metabolizing genes. Collectively, the data suggest EPA prevents hyperinsulinemia and hyperglycemia, in part, through RvE1's activation of ERV1/ChemR23 in a host genetic manner. The studies underscore the need for personalized administration of RvE1 based on genetic/metabolic enzyme profiles.

The Effect of Dietary Fiber Modifications in Purified Diets Relative to Grain-Based Diets on Gastrointestinal Anatomy and Intestinal Microbial Communities in Mice

Objectives

The use of compositionally defined purified diets (PDs)—diets with known sources and quantities of all nutrients—permits investigators to control this major environmental factor in rodent studies. However, mice fed a standard PD exhibit abnormal gastrointestinal (GI) anatomy compared to mice fed Purina 5001, a grain-based diet (GBD). Interestingly, the addition a soluble fiber (inulin) to PDs (typically only containing cellulose, an insoluble fiber) ameliorates these adverse effects. The impact of PDs on the intestinal microbiota has not yet been investigated. We therefore sought to identify PD-supplemented fiber(s) that best recapitulate the GI health and intestinal microbiota of mice fed a GBD, while also including an additional reference GBD (Teklad 2020SX).

Methods

7-week-old C57BL/6J male mice were individually housed and randomly assigned to a diet (two GBDs and four PDs with varying fiber composition) for 28 days. To assess changes in GI anatomy, small intestinal and colon lengths and colon and cecal weights were recorded at tissue harvest. Cecal contents, colon contents, and fecal pellets were collected for 16S rRNA gene sequencing to compare microbial profiles across different GI niches and between diets using the Divisive Amplicon Denoising Algorithm (DADA2) pipeline.

Results

Consistent with published data, GI anatomy was altered in mice consuming PDs compared to the Purina GBD. However, there were no significant anatomical differences between mice consuming PDs and the Teklad GBD. Characterization of microbial communities revealed that the GI niche (cecum, colon, or feces) dictated microbial composition (P &lt; 0.001, ANOSIM). Microbiotas from mice fed any PD significantly differed from mice consuming either GBD (P &lt; 0.05, ANOSIM). Microbiotas were also distinct between mice fed either Purina 5001 or Teklad 2020SX (P &lt; 0.01, ANOSIM).

Conclusions

These data suggest that Purina 5001 does not represent all GBDs and that PDs may not significantly alter rodent GI anatomy compared to GBDs. As each diet tested significantly altered the microbial community, future work will seek to determine whether a specific PD-associated gut microbiota is beneficial to GI health.

Funding Sources

The NIH, the Honors Carolina Sarah Steele Danhoff Undergraduate Research Fund, and Research Diets, Inc.

Perioperative opioid use and pain-related outcomes in the Veterans Health Administration

Understanding variation in perioperative opioid exposure and its effect on patients' outcomes is critical for pain management. This study characterized perioperative exposure to morphine and its association with postoperative pain and 30-day readmissions. We utilized nationwide Veterans Healthcare Administration (VHA) data on four high-volume surgical procedures, 2007-2014. We identified 235,239 Veterans undergoing orthopedic, general, or vascular surgery; 5.4% high trajectories (116.1 OME/Day), 53.2% medium trajectories (39.7 OME/Day), and 41.4% low trajectories (19.1 OME/Day). Modeled estimates suggest that patients in the high OME group had higher risk of a pain-related readmission (OR: 1.59; CI: 1.39, 1.83) compared to the low OME trajectory. Yet when stratified by pain trajectory, patients with high pain and high OME had lower risk of a pain-related readmission compared to patients in the high pain low OME group (OR: 0.76, CI: 0.62, 0.94). In conclusion, patients receiving high perioperative OME are more likely to return to care for pain-related problems. This study highlights opportunities to reduce the amount of prescriptions opioids in the communities.

Integrating Adjuvant Analgesics into Perioperative Pain Practice: Results from an Academic Medical Center

BACKGROUND

Opioid-sparing postoperative pain management therapies are important considering the opioid epidemic. Total knee arthroplasty (TKA) is a common and painful procedure accounting for a large number of opioid prescriptions. Adjuvant analgesics, nonopioid drugs with primary indications other than pain, have shown beneficial pain management and opioid-sparing effects following TKA in clinical trials. We evaluated the adjuvant analgesic gabapentin for its usage patterns and its effects on opioid use, pain, and readmissions.

METHODS

This retrospective, observational study included 4,046 patients who received primary TKA between 2009 and 2017 using electronic health records from an academic tertiary care medical institute. Descriptive statistics and multivariate modeling were used to estimate associations between inpatient gabapentin use and adverse pain outcomes as well as inpatient oral morphine equivalents per day (OME).

RESULTS

Overall, there was an 8.72% annual increase in gabapentin use (P < 0.001). Modeled estimates suggest that gabapentin is associated with a significant decrease in opioid consumption (estimate = 0.63, 95% confidence interval = 0.49-0.82, P < 0.001) when controlling for patient characteristics. Patients receiving gabapentin had similar discharge pain scores, follow-up pain scores, and 30-day unplanned readmission rates compared with patients receiving no adjuvant analgesics (P > 0.05).

CONCLUSIONS

When assessed in a real-world setting over a large cohort of TKA patients, gabapentin is an effective pain management therapy that is associated with reduced opioid consumption-a national priority in this time of opioid crisis-while maintaining the same quality of pain management.

Trajectory analysis for postoperative pain using electronic health records: A nonparametric method with robust linear regression and K-medians cluster analysis

Postoperative pain scores are widely monitored and collected in the electronic health record, yet current methods fail to fully leverage the data with fast implementation. A robust linear regression was fitted to describe the association between the log-scaled pain score and time from discharge after total knee replacement. The estimated trajectories were used for a subsequent K-medians cluster analysis to categorize the longitudinal pain score patterns into distinct clusters. For each cluster, a mixture regression model estimated the association between pain score and time to discharge adjusting for confounding. The fitted regression model generated the pain trajectory pattern for given cluster. Finally, regression analyses examined the association between pain trajectories and patient outcomes. A total of 3442 surgeries were identified with a median of 22 pain scores at an academic hospital during 2009-2016. Four pain trajectory patterns were identified and one was associated with higher rates of outcomes. In conclusion, we described a novel approach with fast implementation to model patients' pain experience using electronic health records. In the era of big data science, clinical research should be learning from all available data regarding a patient's episode of care instead of focusing on the "average" patient outcomes.

Effect of Perioperative Gabapentin on Postoperative Pain Resolution and Opioid Cessation in a Mixed Surgical Cohort: A Randomized Clinical Trial

Importance

Guidelines recommend using gabapentin to decrease postoperative pain and opioid use, but significant variation exists in clinical practice.

Objective

To determine the effect of perioperative gabapentin on remote postoperative time to pain resolution and opioid cessation.

Design, Setting, and Participants

A randomized, double-blind, placebo-controlled trial of perioperative gabapentin was conducted at a single-center, tertiary referral teaching hospital. A total of 1805 patients aged 18 to 75 years scheduled for surgery (thoracotomy, video-assisted thoracoscopic surgery, total hip replacement, total knee replacement, mastectomy, breast lumpectomy, hand surgery, carpal tunnel surgery, knee arthroscopy, shoulder arthroplasty, and shoulder arthroscopy) were screened. Participants were enrolled from May 25, 2010, to July 25, 2014, and followed up for 2 years postoperatively. Intention-to-treat analysis was used in evaluation of the findings.

Interventions

Gabapentin, 1200 mg, preoperatively and 600 mg, 3 times a day postoperatively or active placebo (lorazepam, 0.5 mg) preoperatively followed by inactive placebo postoperatively for 72 hours.

Main Outcomes and Measures

Primary outcome was time to pain resolution (5 consecutive reports of 0 of 10 possible levels of average pain at the surgical site on the numeric rating scale of pain). Secondary outcomes were time to opioid cessation (5 consecutive reports of no opioid use) and the proportion of participants with continued pain or opioid use at 6 months and 1 year.

Results

Of 1805 patients screened for enrollment, 1383 were excluded, including 926 who did not meet inclusion criteria and 273 who declined to participate. Overall, 8% of patients randomized were lost to follow-up. A total of 202 patients were randomized to active placebo and 208 patients were randomized to gabapentin in the intention-to-treat analysis (mean [SD] age, 56.7 [11.7] years; 256 (62.4%) women and 154 (37.6%) men). Baseline characteristics of the groups were similar. Perioperative gabapentin did not affect time to pain cessation (hazard ratio [HR], 1.04; 95% CI, 0.82-1.33; P = .73) in the intention-to-treat analysis. However, participants receiving gabapentin had a 24% increase in the rate of opioid cessation after surgery (HR, 1.24; 95% CI, 1.00-1.54; P = .05). No significant differences were noted in the number of adverse events as well as the rate of medication discontinuation due to sedation or dizziness (placebo, 42 of 202 [20.8%]; gabapentin, 52 of 208 [25.0%]).

Conclusions and Relevance

Perioperative administration of gabapentin had no effect on postoperative pain resolution, but it had a modest effect on promoting opioid cessation after surgery. The routine use of perioperative gabapentin may be warranted to promote opioid cessation and prevent chronic opioid use. Optimal dosing and timing of perioperative gabapentin in the context of specific operations to decrease opioid use should be addressed in further research.

Trial Registration

clinicaltrials.gov Identifier: NCT01067144.

Reconceptualizing anorexia nervosa

Anorexia nervosa (AN) has one of the highest mortality rates of any psychiatric disorder. Treatments are often ineffective and relapse is common. Most research attempting to understand the underlying causes and maintenance factors of AN has focused on environmental contributions, yet there is much to be explored in terms of biological risk and maintenance factors. In this paper, we focus primarily on AN research related to genetics and the complex microbial community in the gut (intestinal microbiota), and how these impact our conceptualization of this disorder. Emerging research identifying significant negative genetic correlations between AN and obesity suggests that the conditions may represent 'metabolic bookends'. The identification of underlying biological mechanisms may provide both insight into extreme weight dysregulation on both ends of the spectrum and new possible points of entry for AN treatment. Additionally, the reported microbial imbalance (dysbiosis) in the gut microbiota in AN patients, potentially due to a nutrient- and energy-deprived gut environment, implies alterations in functional and metabolic capacity of the gut microbiome. The extent to which AN and obesity can also be considered to be 'microbiome bookends' requires further investigation. Finally, we discuss ongoing and future AN projects exploring the interplay between host genomics, the environment, and cumulative microbial genomes (microbiome) as well as interventions at the microbial and gut level.

Factors Associated With Acute Pain Estimation, Postoperative Pain Resolution, Opioid Cessation, and Recovery: Secondary Analysis of a Randomized Clinical Trial

IMPORTANCE

Acute postoperative pain is associated with the development of persistent postsurgical pain, but it is unclear which aspect is most estimable.

OBJECTIVE

To identify patient clusters based on acute pain trajectories, preoperative psychosocial characteristics associated with the high-risk cluster, and the best acute pain predictor of remote outcomes.

DESIGN, SETTING, AND PARTICIPANTS

A secondary analysis of the Stanford Accelerated Recovery Trial randomized, double-blind clinical trial was conducted at a single-center, tertiary, referral teaching hospital. A total of 422 participants scheduled for thoracotomy, video-assisted thoracoscopic surgery, total hip replacement, total knee replacement, mastectomy, breast lumpectomy, hand surgery, carpal tunnel surgery, knee arthroscopy, shoulder arthroplasty, or shoulder arthroscopy were enrolled between May 25, 2010, and July 25, 2014. Data analysis was performed from January 1 to August 1, 2018.

INTERVENTIONS

Patients were randomized to receive gabapentin (1200 mg, preoperatively, and 600 mg, 3 times a day postoperatively) or active placebo (lorazepam, 0.5 mg preoperatively, inactive placebo postoperatively) for 72 hours.

MAIN OUTCOMES AND MEASURES

A modified Brief Pain Inventory prospectively captured 3 surgical site pain outcomes: average pain and worst pain intensity over the past 24 hours, and current pain intensity. Within each category, acute pain trajectories (first 10 postoperative pain scores) were compared using a k-means clustering algorithm. Fifteen descriptors of acute pain were compared as predictors of remote postoperative pain resolution, opioid cessation, and full recovery.

RESULTS

Of the 422 patients enrolled, 371 patients (≤10% missing pain scores) were included in the analysis. Of these, 146 (39.4%) were men; mean (SD) age was 56.67 (11.70) years. Two clusters were identified within each trajectory category. The high pain cluster of the average pain trajectory significantly predicted prolonged pain (hazard ratio [HR], 0.63; 95% CI, 0.50-0.80; P < .001) and delayed opioid cessation (HR, 0.52; 95% CI, 0.41-0.67; P < .001) but was not a predictor of time to recovery in Cox proportional hazards regression (HR, 0.89; 95% CI, 0.69-1.14; P = .89). Preoperative risk factors for categorization to the high average pain cluster included female sex (adjusted relative risk [ARR], 1.36; 95% CI, 1.08-1.70; P = .008), elevated preoperative pain (ARR, 1.11; 95% CI, 1.07-1.15; P < .001), a history of alcohol or drug abuse treatment (ARR, 1.90; 95% CI, 1.42-2.53; P < .001), and receiving active placebo (ARR, 1.27; 95% CI, 1.03-1.56; P = .03). Worst pain reported on postoperative day 10 was the best predictor of time to pain resolution (HR, 0.83; 95% CI, 0.78-0.87; P < .001), opioid cessation (HR, 0.84; 95% CI, 0.80-0.89; P < .001), and complete surgical recovery (HR, 0.91; 95% CI, 0.86-0.96; P < .001).

CONCLUSIONS AND RELEVANCE

This study has shown a possible uniform predictor of remote postoperative pain, opioid use, and recovery that can be easily assessed. Future work is needed to replicate these findings.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01067144.

A High-Throughput Organoid Microinjection Platform to Study Gastrointestinal Microbiota and Luminal Physiology

Background & Aims

The human gut microbiota is becoming increasingly recognized as a key factor in homeostasis and disease. The lack of physiologically relevant in vitro models to investigate host-microbe interactions is considered a substantial bottleneck for microbiota research. Organoids represent an attractive model system because they are derived from primary tissues and embody key properties of the native gut lumen; however, access to the organoid lumen for experimental perturbation is challenging. Here, we report the development and validation of a high-throughput organoid microinjection system for cargo delivery to the organoid lumen and high-content sampling.

Methods

A microinjection platform was engineered using off-the-shelf and 3-dimensional printed components. Microinjection needles were modified for vertical trajectories and reproducible injection volumes. Computer vision (CVis) and microfabricated CellRaft Arrays (Cell Microsystems, Research Triangle Park, NC) were used to increase throughput and enable high-content sampling of mock bacterial communities. Modeling preformed using the COMSOL Multiphysics platform predicted a hypoxic luminal environment that was functionally validated by transplantation of fecal-derived microbial communities and monocultures of a nonsporulating anaerobe.

Results

CVis identified and logged locations of organoids suitable for injection. Reproducible loads of 0.2 nL could be microinjected into the organoid lumen at approximately 90 organoids/h. CVis analyzed and confirmed retention of injected cargos in approximately 500 organoids over 18 hours and showed the requirement to normalize for organoid growth for accurate assessment of barrier function. CVis analyzed growth dynamics of a mock community of green fluorescent protein- or Discosoma sp. red fluorescent protein-expressing bacteria, which grew within the organoid lumen even in the presence of antibiotics to control media contamination. Complex microbiota communities from fecal samples survived and grew in the colonoid lumen without appreciable changes in complexity.

Conclusions

High-throughput microinjection into organoids represents a next-generation in vitro approach to investigate gastrointestinal luminal physiology and the gastrointestinal microbiota.

Utilization and effectiveness of multimodal discharge analgesia for postoperative pain management

BACKGROUND

Although evidence-based guidelines recommend a multimodal approach to pain management, limited information exists on adherence to these guidelines and its association with outcomes in a generalized population. We sought to assess the association between discharge multimodal analgesia and postoperative pain outcomes in two diverse health care settings.

METHODS

We evaluated patients undergoing four common surgeries associated with high pain in electronic health records from an academic hospital (AH) and Veterans Health Administration (VHA). Multimodal analgesia at discharge was characterized as opioids in combination with acetaminophen (O + A) and nonsteroidal antiinflammatory (O + A + N) drugs. Hierarchical models estimated associations of analgesia with 45-d follow-up pain scores and 30-d readmissions.

RESULTS

We identified 7893 patients at AH and 34,581 at VHA. In both settings, most patients were discharged with O + A (60.6% and 54.8%, respectively), yet a significant proportion received opioids alone (AH: 24.3% and VHA: 18.8%). Combining acetaminophen with opioids was associated with decreased follow-up pain in VHA (Odds ratio [OR]: 0.86, 95% confidence interval [CI]: 0.79, 0.93) and readmissions (AH OR: 0.74, CI: 0.60, 0.90; VHA OR: 0.89, CI: 0.82, 0.96). Further addition of nonsteroidal antiinflammatory drugs was associated with further decreased follow-up pain (AH OR: 0.71, CI: 0.53, 0.96; VHA OR: 0.77, CI: 0.69, 0.86) and readmissions (AH OR: 0.46, CI: 0.31, 0.69; VHA OR: 0.84, CI: 0.76, 0.93). In both systems, patients receiving multimodal analgesia received 10%-40% less opioids per day compared to opioids only.

CONCLUSIONS

A majority of surgical patients receive a multimodal pain approach at discharge yet many receive only opioids. Multimodal regimen at discharge was associated with better follow-up pain and all-cause readmissions compared to the opioid-only regimen.

Ondansetron does not prevent physical dependence in patients taking opioid medications chronically for pain control

OBJECTIVES

In this study, we investigated the co-administration of ondansetron with morphine, and whether it could prevent the development of physical dependence in patients taking opioids for the treatment of chronic pain.

METHODS

A total of 48 chronic back pain patients (N = 48) participated in this double-blinded, placebo-controlled, randomized study. Patients were titrated onto sustained-release oral morphine and randomized to take 8 mg ondansetron or placebo three times daily concurrently with morphine during the 30-day titration. Following titration, patients underwent Naloxone induced opioid withdrawal. Opioid withdrawal signs and symptoms were then assessed by a blinded research assistant (objective opioid withdrawal score: OOWS) and by the research participant (subjective opioid withdrawal score: SOWS).

RESULTS

We observed clinically significant signs of naloxone-precipitated opioid withdrawal in all participants (ΔOOWS = 4.3 ± 2.4, p < 0.0001; ΔSOWS = 14.1 ± 11.7, p < 0.0001), however no significant differences in withdrawal scores were detected between treatment groups.

CONCLUSION

We hypothesized that ondansetron would prevent the development of physical dependence in human subjects when co-administered with opioids, but found no difference in naloxone-precipitated opioid withdrawal scores between ondansetron and placebo treatment groups. These results suggest that further studies are needed to determine if 5HT₃ receptor antagonists are useful in preventing opioid physical dependence.

The S-layer Associated Serine Protease Homolog PrtX Impacts Cell Surface-Mediated Microbe-Host Interactions of Lactobacillus acidophilus NCFM

Health-promoting aspects attributed to probiotic microorganisms, including adhesion to intestinal epithelia and modulation of the host mucosal immune system, are mediated by proteins found on the bacterial cell surface. Notably, certain probiotic and commensal bacteria contain a surface (S-) layer as the outermost stratum of the cell wall. S-layers are non-covalently bound semi-porous, crystalline arrays of self-assembling, proteinaceous subunits called S-layer proteins (SLPs). Recent evidence has shown that multiple proteins are non-covalently co-localized within the S-layer, designated S-layer associated proteins (SLAPs). In Lactobacillus acidophilus NCFM, SLP and SLAPs have been implicated in both mucosal immunomodulation and adhesion to the host intestinal epithelium. In this study, a S-layer associated serine protease homolog, PrtX (prtX, lba1578), was deleted from the chromosome of L. acidophilus NCFM. Compared to the parent strain, the PrtX-deficient strain (ΔprtX) demonstrated increased autoaggregation, an altered cellular morphology, and pleiotropic increases in adhesion to mucin and fibronectin, in vitro. Furthermore, ΔprtX demonstrated increased in vitro immune stimulation of IL-6, IL-12, and IL-10 compared to wild-type, when exposed to mouse dendritic cells. Finally, in vivo colonization of germ-free mice with ΔprtX led to an increase in epithelial barrier integrity. The absence of PrtX within the exoproteome of a ΔprtX strain caused morphological changes, resulting in a pleiotropic increase of the organisms’ immunomodulatory properties and interactions with some intestinal epithelial cell components.

DNA-graphene interactions during translocation through nanogaps

We study how double-stranded DNA translocates through graphene nanogaps. Nanogaps are fabricated with a novel capillary-force induced graphene nanogap formation technique. DNA translocation signatures for nanogaps are qualitatively different from those obtained with circular nanopores, owing to the distinct shape of the gaps discussed here. Translocation time and conductance values vary by ∼ 100%, which we suggest are caused by local gap width variations. We also observe exponentially relaxing current traces. We suggest that slow relaxation of the graphene membrane following DNA translocation may be responsible. We conclude that DNA-graphene interactions are important, and need to be considered for graphene-nanogap based devices. This work further opens up new avenues for direct read of single molecule activitities, and possibly sequencing.

Rifaximin Exerts Beneficial Effects Independent of its Ability to Alter Microbiota Composition

OBJECTIVES

Rifaximin has clinical benefits in minimal hepatic encephalopathy (MHE) but the mechanism of action is unclear. The antibiotic-dependent and -independent effects of rifaximin need to be elucidated in the setting of MHE-associated microbiota. To assess the action of rifaximin on intestinal barrier, inflammatory milieu and ammonia generation independent of microbiota using rifaximin.

METHODS

Four germ-free (GF) mice groups were used (1) GF, (2) GF+rifaximin, (3) Humanized with stools from an MHE patient, and (4) Humanized+rifaximin. Mice were followed for 30 days while rifaximin was administered in chow at 100 mg/kg from days 16-30. We tested for ammonia generation (small-intestinal glutaminase, serum ammonia, and cecal glutamine/amino-acid moieties), systemic inflammation (serum IL-1β, IL-6), intestinal barrier (FITC-dextran, large-/small-intestinal expression of IL-1β, IL-6, MCP-1, e-cadherin and zonulin) along with microbiota composition (colonic and fecal multi-tagged sequencing) and function (endotoxemia, fecal bile acid deconjugation and de-hydroxylation).

RESULTS

All mice survived until day 30. In the GF setting, rifaximin decreased intestinal ammonia generation (lower serum ammonia, increased small-intestinal glutaminase, and cecal glutamine content) without changing inflammation or intestinal barrier function. Humanized microbiota increased systemic/intestinal inflammation and endotoxemia without hyperammonemia. Rifaximin therapy significantly ameliorated these inflammatory cytokines. Rifaximin also favorably impacted microbiota function (reduced endotoxin and decreased deconjugation and formation of potentially toxic secondary bile acids), but not microbial composition in humanized mice.

CONCLUSIONS

Rifaximin beneficially alters intestinal ammonia generation by regulating intestinal glutaminase expression independent of gut microbiota. MHE-associated fecal colonization results in intestinal and systemic inflammation in GF mice, which is also ameliorated with rifaximin.

Discordant temporal development of bacterial phyla and the emergence of core in the fecal microbiota of young children

The colonization pattern of intestinal microbiota during childhood may impact health later in life, but children older than 1 year are poorly studied. We followed healthy children aged 1-4 years (n=28) for up to 12 months, during which a synbiotic intervention and occasional antibiotics intake occurred, and compared them with adults from the same region. Microbiota was quantified with the HITChip phylogenetic microarray and analyzed with linear mixed effects model and other statistical approaches. Synbiotic administration increased the stability of Actinobacteria and antibiotics decreased Clostridium cluster XIVa abundance. Bacterial diversity did not increase in 1- to 5-year-old children and remained significantly lower than in adults. Actinobacteria, Bacilli and Clostridium cluster IV retained child-like abundances, whereas some other groups were converting to adult-like profiles. Microbiota stability increased, with Bacteroidetes being the main contributor. The common core of microbiota in children increased with age from 18 to 25 highly abundant genus-level taxa, including several butyrate-producing organisms, and developed toward an adult-like composition. In conclusion, intestinal microbiota is not established before 5 years of age and diversity, core microbiota and different taxa are still developing toward adult-type configuration. Discordant development patterns of bacterial phyla may reflect physiological development steps in children.

Management of chronic pain following nerve injuries/CRPS type II

Chronic pain affects quality of life and adversely affects functional outcomes. Chronic postoperative pain is a frustrating problem for the surgeon because it ruins a technically perfect procedure, and the surgeon may be unsure of treatment strategies. There is much information on chronic pain and its treatment, but it is often published outside of surgery and diffusion of this information across disciplines is slow. This article synthesizes some of this literature and provides a systematic presentation of the evidence on pain associated with peripheral nerve injury. It highlights the use of perioperative and early intervention to decrease this debilitating problem.