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This series is automatically populated with publications deposited by UC San Diego School of Medicine Department of Anesthesiology researchers in accordance with the University of California’s open access policies. For more information see Open Access Policy Deposits and the UC Publication Management System.

Cover page of Disparities Exist in the Application of Low Tidal-volume Ventilation in the Emergency Department

Disparities Exist in the Application of Low Tidal-volume Ventilation in the Emergency Department

(2023)

Introduction: Low tidal-volume ventilation (LTVV), defined as a maximum tidal volume of 8 milliliters per kilogram (mL/kg) of ideal body weight, is a key component of lung protective ventilation. Although emergency department (ED) initiation of LTVV has been associated with improved outcomes, disparities in LTVV application exist. In this study our aim was to evaluate whether rates of LTVV are associated with demographic and physical characteristics in the ED.

Methods: We conducted a retrospective observational cohort study using a dataset of patients who underwent mechanical ventilation at three EDs in two health systems from January 2016–June 2019. Demographic, mechanical ventilation, and outcome data including mortality and hospital-free days were abstracted by automatic query. A LTVV approach was defined as a tidal volume ≤8 mL/kg ideal body weight. We performed descriptive statistics and univariate analysis as indicated, and created a multivariate logistic regression model.

Results: Of 1,029 patients included in the study, 79.5% received LTVV. Tidal volumes of 400-500 mL were used in 81.9% of patients. Approximately 18% of patients had tidal volumes changed in the ED. Female gender (adjusted odds ratio [aOR] 4.17, P< 0.001), obesity (aOR 2.27, P< 0.001), and first-quartile height (aOR 12.2, P < 0.001) were associated with receiving non-LTVV in multivariate regression analysis. Hispanic ethnicity and female gender were associated with first quartile height (68.5%, 43.7%, P < 0.001 for all). Hispanic ethnicity was associated with receiving non-LTVV in univariate analysis (40.8% vs 23.0%, P < 0.001). This relationship did not persist in sensitivity analysis controlling for height, weight, gender, and body mass index. Patients who received LTVV in the ED had 2.1 more hospital-free days compared to those who did not (P = 0.040). No difference in mortality was observed.

Conclusion: Emergency physicians use a narrow range of initial tidal volumes that may not meet lung-protective ventilation goals, with few corrections. Female gender, obesity, and first-quartile height are independently associated with receiving non-LTVV in the ED. Using LTVV in the ED was associated with 2.1 fewer hospital-free days. If confirmed in future studies, these findings have important implications for achieving quality improvement and health equality.

 

Cover page of Can Emergency Medicine Residents Predict Cost of Diagnostic Testing?

Can Emergency Medicine Residents Predict Cost of Diagnostic Testing?

(2017)

INTRODUCTION:  Diagnostic testing represents a significant portion of healthcare spending, and cost should be considered when ordering such tests.  Needless and excessive spending may occur without an appreciation of the impact on the larger health care system. Knowledge regarding the cost of diagnostic testing among Emergency Medicine residents has not previously been studied.

METHODS: A survey was administered to 20 Emergency Medicine residents from a single ACGME-accredited three-year EM residency program, asking an estimation of the patient charges for 20 commonly ordered laboratory tests and 7 radiological exams. Responses were compared between residency classes to evaluate whether there was a difference based on level of training.

RESULTS: The survey completion rate was 100% (20/20 residents).  Significant discrepancies were noted between the median resident estimates and actual charge to patient for both laboratory and radiological exams.  Nearly all responses were an underestimate of the actual cost. The group median underestimation for laboratory testing was $114, for radiographs $57, and for computed tomography (CT) exams was $1058.   There was statistically significant improvement in accuracy with increasing level of training.

CONCLUSION: This pilot study demonstrates that EM residents have a poor understanding of the charges burdened by patients and health insurance providers.  In order to make balanced decisions with regard to diagnostic testing, providers must appreciate these factors.  Education regarding the cost of providing emergency care is a potential area for improvement of Emergency Medicine residency curricula, and warrants further attention and investigation.

Cover page of Wearable, noninvasive, pulsed shortwave (radiofrequency) therapy for postoperative analgesia: A randomized, double-masked, sham-controlled pilot study.

Wearable, noninvasive, pulsed shortwave (radiofrequency) therapy for postoperative analgesia: A randomized, double-masked, sham-controlled pilot study.

(2025)

BACKGROUND: Nonthermal, pulsed shortwave (radiofrequency) therapy (PSWT) is a nonpharmacologic, noninvasive modality that limited evidence suggests provides analgesia. Its potential favorable risk-benefit ratio stems from its lack of side effects and significant medical risks, applicability to any anatomic location, long treatment duration, and ease of application by simply affixing it with tape. Even with a relatively small treatment effect, PSWT might contribute to a multimodal analgesic regimen, similar to acetaminophen. However, widespread clinical use is hindered by a lack of systematic evidence. The current randomized, controlled pilot study was undertaken to determine the feasibility and optimize the protocol for a subsequent definitive investigation and estimate the treatment effect of PSWT on postoperative pain and opioid consumption. METHODS: Within the recovery room following primary knee and hip arthroplasty, cholecystectomy, hernia repair, and non-mastectomy breast surgery, we applied 1-3 PSWT devices (Model 088, BioElectronics Corporation, Frederick, Maryland) over the surgical bandages. Participants were randomized to 28 days of either active or sham treatment in a double-masked fashion. The outcomes of primary interest were the cumulative opioid consumption and the mean of the average and worst daily pain measured with the Numeric Rating Scale over the first 7 postoperative days. RESULTS: During the first 7 postoperative days, oxycodone consumption in participants given active treatment (n = 55) was a mean (SD) of 21 mg (24) versus 17 mg (26) in patients given sham (n = 57): difference 4 (95% CI, -5 to 13), p = 0.376. During this same period, the average daily pain intensity in patients given active treatment was 2.4 (1.6) versus 2.6 (1.7) in sham: difference -0.2 (95% CI -0.8 to 0.5), p = 0.597. Concurrently, the worst/maximum pain for the active group was 4.6 (2.0) versus 4.7 (2.1) in sham: difference -0.1 (95% CI -0.8 to 0.7), p = 0.888. No device-related systemic side effects or serious adverse events were identified. CONCLUSIONS: Pulsed shortwave (radiofrequency) therapy did not reduce pain scores and opioid requirements to a statistically significant or clinically relevant degree during the initial postoperative week in this pilot study. These results must be replicated with a subsequent study before being considered definitive. Data from this preliminary study may be used to help plan future trials.

Cover page of Demographic disparities in access to COVID-19 clinical trial sites across the United States: a geospatial analysis.

Demographic disparities in access to COVID-19 clinical trial sites across the United States: a geospatial analysis.

(2025)

Throughout the COVID-19 pandemic, underserved populations, such as racial and ethnic minority communities, were disproportionately impacted by illness and death. Ensuring people from diverse backgrounds have the ability to participate in clinical trials is key to advancing health equity. We sought to analyze the spatial variability in locations of COVID-19 trials sites and to test associations with demographic correlates. All available and searchable COVID-19 studies listed on ClinicalTrials.gov until 04/04/2022 and conducted in the United States were extracted at the trial-level, and locations were geocoded using the Microsoft Bing API. Publicly available demographic data were available at the county level for national analysis and the census tract level for local analysis. Independent variables included eight racial and ethnic covariates, both sexes, and twelve age categories, all of which were population-normalized. The county-level, population-normalized count of study site locations, by type, was used as the outcome for national analysis, thereby enabling the determination of demographic associations with geospatial availability to enroll as a participant in a COVID-19 study. Z-scores of the Getis-Ord Gi statistic were used as the outcome for local analysis in order to account for areas close to those with clinical study sites. For both national (p < 0.001) and local analysis (p = 0.006 for Los Angeles, p = 0.030 for New York), areas with greater proportions of men had significantly fewer studies. Sites were more likely to be found in counties with higher proportions of Asian (p < 0.001) and American Indian or Alaska Native residents (p < 0.001). Areas with greater concentrations of Black or African American residents had significantly lower concentrations of observational (p < 0.001) and government-sponsored COVID-19 studies (p = 0.003) in national analysis and significantly fewer concentrations of study sites in both Los Angeles (p < 0.001) and New York (p = 0.007). Though there appear to be a large number of COVID-19 studies that commenced in the US, they are distributed unevenly, both nationally and locally.

Cover page of Next generation bioelectronic medicine: making the case for non-invasive closed-loop autonomic neuromodulation.

Next generation bioelectronic medicine: making the case for non-invasive closed-loop autonomic neuromodulation.

(2025)

The field of bioelectronic medicine has advanced rapidly from rudimentary electrical therapies to cutting-edge closed-loop systems that integrate real-time physiological monitoring with adaptive neuromodulation. Early innovations, such as cardiac pacemakers and deep brain stimulation, paved the way for these sophisticated technologies. This review traces the historical and technological progression of bioelectronic medicine, culminating in the emerging potential of closed-loop devices for multiple disorders of the brain and body. We emphasize both invasive techniques, such as implantable devices for brain, spinal cord and autonomic regulation, while we introduce new prospects for non-invasive neuromodulation, including focused ultrasound and newly developed autonomic neurography enabling precise detection and titration of inflammatory immune responses. The case for closed-loop non-invasive autonomic neuromodulation (incorporating autonomic neurography and splenic focused ultrasound stimulation) is presented through its applications in conditions such as sepsis and chronic inflammation, illustrating its capacity to revolutionize personalized healthcare. Today, invasive or non-invasive closed-loop systems have yet to be developed that dynamically modulate autonomic nervous system function by responding to real-time physiological and molecular signals; it represents a transformative approach to therapeutic interventions and major opportunity by which the bioelectronic field may advance. Knowledge gaps remain and likely contribute to the lack of available closed loop autonomic neuromodulation systems, namely, (1) significant exogenous and endogenous noise that must be filtered out, (2) potential drift in the signal due to temporal change in disease severity and/or therapy induced neuroplasticity, and (3) confounding effects of exogenous therapies (e.g., concurrent medications that dysregulate autonomic nervous system functions). Leveraging continuous feedback and real-time adjustments may overcome many of these barriers, and these next generation systems have the potential to stand at the forefront of precision medicine, offering new avenues for individualized and adaptive treatment.

Cover page of Ultrasound-Guided Percutaneous Cryoneurolysis for the Treatment of Pain following Traumatic Rib Fracture: A Randomized, Active-Controlled, Participant- and Observer-Masked Study.

Ultrasound-Guided Percutaneous Cryoneurolysis for the Treatment of Pain following Traumatic Rib Fracture: A Randomized, Active-Controlled, Participant- and Observer-Masked Study.

(2024)

BACKGROUND: Traumatic rib fractures are associated with pain lasting weeks to months and a decreased ability to inspire deeply or cough to clear secretions. Ultrasound-guided percutaneous cryoneurolysis involves reversibly ablating peripheral nerve(s) using exceptionally low temperature with a transdermal probe, resulting in a prolonged nerve block with a duration measured in months. We hypothesized that cryoneurolysis would improve analgesia and inspired volume following rib fracture. METHODS: Adults with 1-6 traumatic rib fractures were randomized to either active cryoneurolysis and a sham peripheral nerve block (PNB), or sham cryoneurolysis and active PNB in a participant/observer-masked fashion. The primary endpoint was the maximum inspired volume the day after the procedure as measured with an incentive spirometer. RESULTS: The day after the procedure, the unadjusted median [IQR] maximum inspired volume for participants who received cryoneurolysis (n=11) was 2,250 mL [1,500; 2,500] versus 1,300 mL [750; 2,500] for PNB (n=9, mean difference 496; 95%CI -428 to 1420; t-test P=0.269). When adjusted for covariates (e.g., baseline lung volume), the cryoneurolysis group had an estimated 793 mL greater mean volume than PNB (95%CI 273 to 1,312; ANCOVA P=0.005). Improvement from baseline in maximum inspired volume for cryoneurolysis was 1,000 mL [1,000; 1,375] versus 300 mL [0; 1,000] for PNB (t-test P=0.002). This was equivalent to an improvement over baseline of 100% [90%, 188%] for cryoneurolysis versus 30% [0%, 50%] for PNB (t-test P=0.003). Average daily pain scores were generally lower for the cryoneurolysis group throughout the first month. Total cumulative oxycodone equivalents were 5 mg [0, 13] for cryoneurolysis vs 45 mg [43, 135] for PNB (t-test P=0.013). CONCLUSIONS: Ultrasound-guided percutaneous cryoneurolysis improves maximum inspired lung volume while concurrently decreasing pain and opioid consumption after traumatic rib fracture. These results should be considered preliminary, requiring confirmation with a trial including a larger sample size.

Cover page of Elevated C-Reactive Protein in Older Men With Chronic Pain: Association With Plasma Amyloid Levels and Hippocampal Volume

Elevated C-Reactive Protein in Older Men With Chronic Pain: Association With Plasma Amyloid Levels and Hippocampal Volume

(2024)

Background

Chronic pain leads to tau accumulation and hippocampal atrophy, which may be moderated through inflammation. In older men, we examined associations of chronic pain with Alzheimer's disease (AD)-related plasma biomarkers and hippocampal volume as moderated by systemic inflammation.

Methods

Participants were men without dementia. Chronic pain was defined as moderate-to-severe pain in 2+ study waves at average ages 56, 62, and 68. At age 68, we measured plasma amyloid-beta (Aβ42, n = 871), Aβ40 (n = 887), total tau (t-tau, n = 841), and neurofilament light chain (NfL, n = 915), and serum high-sensitivity C-reactive protein (hs-CRP, n = 968), a marker of systemic inflammation. A subgroup underwent structural MRI to measure hippocampal volume (n = 385). Analyses adjusted for medical morbidities, depressive symptoms, and opioid use.

Results

Chronic pain was related to higher Aβ40 (β = 0.25, p = .009), but hs-CRP was unrelated to AD-related biomarkers (ps > .05). There was a significant interaction such that older men with both chronic pain and higher levels of hs-CRP had higher levels of Aβ42 (β = 0.36, p = .001) and Aβ40 (β = 0.29, p = .003). Chronic pain and hs-CRP did not interact to predict levels of Aβ42/Aβ40, t-tau, or NfL. Furthermore, there were significant interactions such that Aβ42 and Aβ40 were associated with lower hippocampal volume, particularly when levels of hs-CRP were elevated (hs-CRP × Aβ42: β = -0.19, p = .002; hs-CRP × Aβ40: β = -0.21, p = .001), regardless of chronic pain status.

Conclusions

Chronic pain was associated with higher plasma Aβ, especially when hs-CRP was also elevated. Higher hs-CRP and Aβ levels were both related to smaller hippocampal volumes. Chronic pain, when accompanied by systemic inflammation, may elevate the risk of neurodegeneration in AD-vulnerable regions.

Language Dominance and Cultural Identity Predict Variation in Self-Reported Personality in English and Spanish Among Hispanic/Latino Bilingual Adults

(2024)

Language is a fundamental aspect of human culture that influences cognitive and perceptual processes. Prior evidence demonstrates personality self-report can vary across multilingual persons' language contexts. We assessed how cultural identification, language dominance, or both dynamically influence bilingual respondents' self-conception, via self-reported personality, across English and Spanish contexts. During separate English and Spanish conditions, 133 Hispanic/Latino bilingual participants (70 female) completed the Big Five Inventory of personality. We used language use and acculturation surveys completed in both languages to calculate participants' relative language dominance and identification with U.S.-American and Hispanic culture. Participants reported higher levels of agreeableness, conscientiousness, and neuroticism in English relative to Spanish. Language dominance predicted cross-language differences in personality report, with higher extraversion reported in participants' dominant language. Within each language, greater endorsement of U.S.-American identity was associated with higher extraversion and conscientiousness and lower reported neuroticism. Agreeableness report in both languages was positively predicted by Hispanic identification. Our results clarify existing literature related to language and cultural effects on personality report among U.S. Hispanics/Latinos. These findings could inform assessments of self-relevant cognitions across languages among bilingual populations and hold relevance for health outcomes affected by cultural processes.

Cover page of Detection and Characterization of Online Substance Use Discussions Among Gamers: Qualitative Retrospective Analysis of Reddit r/StopGaming Data.

Detection and Characterization of Online Substance Use Discussions Among Gamers: Qualitative Retrospective Analysis of Reddit r/StopGaming Data.

(2024)

BACKGROUND: Video games have rapidly become mainstream in recent decades, with over half of the US population involved in some form of digital gaming. However, concerns regarding the potential harms of excessive, disordered gaming have also risen. Internet gaming disorder (IGD) has been proposed as a tentative psychiatric disorder that requires further study by the American Psychological Association (APA) and is recognized as a behavioral addiction by the World Health Organization. Substance use among gamers has also become a concern, with caffeinated or energy drinks and prescription stimulants commonly used for performance enhancement. OBJECTIVE: This study aimed to identify substance use patterns and health-related concerns among gamers among a population of Reddit users. METHODS: We used the public streaming Reddit application programming interface to collect and analyze all posts from the popular subreddit, r/StopGaming. From this corpus of posts, we filtered the dataset for keywords associated with common substances that may be used to enhance gaming performance. We then applied an inductive coding approach to characterize substance use behaviors, gaming genres, and physical and mental health concerns. Potential disordered gaming behavior was also identified using the tentative IGD guidelines proposed by the APA. A chi-square test of independence was used to assess the association between gaming disorder and substance use characteristics, and multivariable logistic regression was used to analyze whether mental health discussion or the mention of any substance with sufficient sample size was significantly associated with IGD. RESULTS: In total, 10,551 posts were collected from Reddit from June 2017 to December 2022. After filtering the dataset for substance-related keywords, 1057 were included for further analysis, of which 286 mentioned both gaming and the use of ≥1 substances. Among the 286 posts that discussed both gaming and substance use, the most mentioned substances were alcohol (n=132), cannabis (n=104), and nicotine (n=48), while the most mentioned genres were role-playing games (n=120), shooters (n=90), and multiplayer online battle arenas (n=43). Self-reported behavior that aligned with the tentative guidelines for IGD was identified in 66.8% (191/286) posts. More than half, 62.9% (180/286) of the posts, discussed a health issue, with the majority (n=144) cited mental health concerns. Common mental health concerns discussed were depression and anxiety. There was a significant association between IGD and substance use (P<.001; chi-square test), and there were significantly increased odds of IGD among those who self-reported substance use (odds ratio 2.29, P<.001) and those who discussed mental health (odds ratio 1.64, P<.03). CONCLUSIONS: As gaming increasingly becomes highly prevalent among various age groups and demographics, a better understanding of the interplay and convergence among disordered gaming, substance use, and negative health impacts can inform the development of interventions to mitigate risks and promote healthier gaming habits.

Cover page of Self-regulated analgesia in males but not females is mediated by endogenous opioids

Self-regulated analgesia in males but not females is mediated by endogenous opioids

(2024)

Converging lines of preclinical and clinical research indicate that females, in stark contrast to males, display an increased prevalence of chronic pain. Females also demonstrate weaker analgesic efficacy in response to opioid therapies when compared with males. These sex-specific differences may be driven by dimorphic endogenous opioidergic responses. In rodent models, analgesia exhibited in males but not females was reversed by inhibiting endogenous opioidergic reception. In humans, the sex-specific endogenous system(s) supporting the direct attenuation of evoked pain has not been identified. To determine whether opioidergic blockade reverses self-regulated analgesia in males as compared to females, the present study combined two operationally analogous clinical trials (n = 98; 51 females and 47 males). In a double-blinded, counterbalanced study involving healthy (n = 39) and chronic low back pain (n = 59) populations, a high-dose naloxone (μ-, κ-, δ-opioid antagonist) vs. placebo-saline cross-over design (15 mg/kg bolus +0.1 mg/kg/h) tested the hypothesis that endogenous opioids mediate analgesia in males but not females. An 11-point visual analog scale (VAS) (0 = no pain; 10 = worst pain imaginable) evaluated pain ratings in response to noxious heat stimulation (49 °C; calf). After baseline pain testing, participants were randomized to a validated four-session mindfulness meditation or sham mindfulness meditation training intervention. Participants practiced their respective meditation during noxious heat, intravenous high-dose naloxone, and placebo saline, respectively. In males and females, meditation significantly lowered evoked pain during saline infusion. Intravenous naloxone inhibited analgesia in males, but pain relief was well preserved in females. The present findings indicate that endogenous opioids mediate self-regulated analgesia in males but not females and underscore the need to establish sex-specific pain therapeutics.