Back

British Journal of Anaesthesia

Elsevier BV

Preprints posted in the last 30 days, ranked by how well they match British Journal of Anaesthesia's content profile, based on 17 papers previously published here. The average preprint has a 0.02% match score for this journal, so anything above that is already an above-average fit.

1
Large Language Model Embeddings of Surgical Procedural Names for Confounding Adjustment in Perioperative Observational Studies

Han, L.; Ghanem, M.; Simhambhatla, M. K.; Chung, P.; Aghaeepour, N.

2026-08-25 anesthesia 10.64898/2026.08.22.26361065 medRxiv
Top 0.1%
74.3%
Show abstract

Background: Perioperative observational studies are increasingly used to evaluate anesthesia practices that are difficult to test in randomized trials, but treatment selection is influenced by surgical procedure type. Scalable and robust methods are needed to adjust for procedure-level confounding across heterogeneous surgical cohorts. Methods: We developed and assessed the utility of a surgical-name embedding framework using free-text procedure names from 627,624 adult perioperative records. Procedure names were embedded using open-source sentence-embedding models, reduced with principal components analysis, and incorporated into entropy-balanced observational analyses. We compared unweighted, clinical covariate adjustment, and clinical covariate plus surgical-name embedding adjustment across three replications of recent perioperative randomized trials: GA-CARES for total intravenous versus volatile anesthesia on cancer mortality, PADDI for dexamethasone and surgical site infection, and GAP for perioperative gabapentin and postoperative length of stay. Results: In the GA-CARES replication, unweighted and clinical covariate adjustment suggested lower two-year mortality with total intravenous anesthesia, whereas adding surgical-name embeddings attenuated the estimate to a nonsignificant association consistent with the randomized trial (OR 0.84 [95% CI, 0.62-1.14]; p=0.274). In the PADDI replication, adding surgical-name adjustment reproduced the trial's overall non-harm finding for 30-day surgical site infection (OR 0.72 [95% CI 0.69-0.76], p<0.001) while preserving the expected protective association with postoperative nausea and/or vomiting. In the GAP replication, the full cohort was null across adjustment strategies, but surgical-name embeddings were required to recover trial-consistent null length-of-stay estimates across cardiac, thoracic, and abdominal subgroups. Department indicators and randomly generated covariates did not reproduce the effect of surgical-name embeddings, supporting the presence and importance of procedure-specific information. Conclusions: Free-text surgical-name embeddings provide a scalable method for representing surgical context in perioperative observational studies. Surgical-name adjustment improved concordance with randomized trial benchmarks while preserving expected treatment effects, supporting its use as an additional layer of confounding adjustment in large perioperative datasets.

2
Relationships of Preoperative and 24-Hour Postoperative Plasma and Cerebrospinal Fluid Cytokines with Postoperative Delirium

Devinney, M. J.; Simon, J. R.; Wright, M. C.; Chand, S.; Yu, C. T.; Herber, C. S.; Terrando, N.; Browndyke, J.; Whitson, H. E.; Cohen, H. J.; Huebner, J. L.; Klein, M. E.; Moretti, E.; Mathew, J. P.; Berger, M.

2026-08-14 anesthesia 10.64898/2026.08.12.26360137 medRxiv
Top 0.1%
58.5%
Show abstract

Background: Postoperative delirium is a common syndrome of acute changes in attention, cognition, and consciousness that may result from inflammation and/or neuroinflammation, but few studies have distinguished the relationships of preoperative and 24-hour postoperative systemic inflammation (i.e. in blood) versus neuroinflammation (i.e. in cerebrospinal fluid, or CSF) in postoperative delirium. Methods: We measured CSF and plasma cytokine levels before and 24-hours after non-cardiac/non-neurologic surgery in 199 patients age [&ge;] 60 years who were enrolled in two prospective cohort studies. Delirium was assessed with the confusion assessment method (CAM), 3-minute diagnostic interview for CAM-defined delirium, or the CAM for the Intensive Care Unit (CAM-ICU) in patients who remained intubated postoperatively and validated chart review. Cytokines were measured with immunoassays for IL-6, IL-7, IL-8, IL-10, IL-16, TARC, MCP-1, and IP-10. Associations of CSF and plasma cytokine levels with postoperative delirium were assessed with univariable and multivariable logistic regression analyses with Holm correction for family-wise error. Results: Surgery was associated with significant changes in nearly all measured CSF and plasma cytokines (p < 0.05) except plasma IL-16 and MCP-1. In multivariable analyses adjusted for preoperative Mini-Mental Status Exam (MMSE) score and surgery duration, higher preoperative CSF IL-6 (OR 1.80, 95% CI 1.18-2.75, Holm p=0.049) and CSF IL-8 (OR 1.94, 95% CI 1.22-3.06, Holm p = 0.040) levels were independently associated with postoperative delirium. Higher 24-hour postoperative CSF IL-10 was nominally associated with delirium (OR 1.57, 95% CI 1.06-2.33, p = 0.026) in a multivariable regression controlling MMSE and surgery duration, but this association did not remain significant after multiple-comparison correction (Holm p = 0.21). No other preoperative or 24-hour postoperative CSF or plasma cytokine levels were associated with delirium (p > 0.05). Conclusions: Surgery elicited robust postoperative changes in CSF and plasma cytokines, but 24-hour postoperative cytokine elevations were not significantly associated with postoperative delirium after multiple-comparison correction. In contrast, elevated preoperative CSF IL-6 and IL-8 levels were associated with postoperative delirium independent of baseline cognitive status and surgery duration. Thus, our findings support an important role for preoperative neuroinflammation in postoperative delirium in older elective surgery patients.

3
Postoperative analgesia and recovery after minimally invasive cardiac surgery

Note, H.; Kajiura, T.; Muramatsu, A.; Inagaki, Y.; Takahashi, T.; Sato, K.; Nakamura, K.; Sadatoshi, T.; Sakurai, Y.; Tochii, M.; Watanuki, H.; Matsuyama, K.; Okamoto, S.

2026-08-31 intensive care and critical care medicine 10.64898/2026.08.27.26361580 medRxiv
Top 0.1%
41.0%
Show abstract

Introduction Postoperative analgesic management after minimally invasive cardiac surgery (MICS) should facilitate early recovery while providing adequate pain control. However, direct evidence comparing postoperative remifentanil- and fentanyl-based analgesic strategies after MICS remains limited. We compared these strategies and explored their associations with postoperative recovery, postoperative nausea and vomiting (PONV), and pain management. Methods This retrospective single-center observational cohort study included patients who underwent MICS via a right mini-thoracotomy between January 2023 and June 2026. Patients were categorized according to postoperative remifentanil- or fentanyl-based analgesia in the intensive care unit. Outcomes included time to extubation, PONV, postoperative pain assessed using the numerical rating scale (NRS), additional analgesic use, and intensive care unit length of stay. Multivariable logistic regression examined the association between postoperative opioid strategy and PONV, adjusting for age, sex, and smoking history. Results PONV occurred less frequently in the remifentanil group than in the fentanyl group (20.6% vs 45.0%, P = 0.004), and this association remained significant after adjustment (adjusted odds ratio, 0.23; 95% confidence interval, 0.10-0.56; P = 0.001). Time to extubation was shorter with remifentanil (median, 179 [interquartile range, 134-240.5] vs 247 [190.2-276.5] min; P < 0.001). In contrast, NRS pain scores on postoperative day 0 were higher with remifentanil (3 [1-6] vs 1 [0-2]; P < 0.001), and additional analgesics were used more frequently (80.6% vs 33.3%; P < 0.001). Pain scores on postoperative day 1 did not differ significantly between groups. Conclusion Postoperative remifentanil-based analgesia after MICS was associated with less PONV and earlier extubation but also with greater early postoperative pain and more frequent additional analgesic use than fentanyl-based analgesia. Appropriate transition to longer-acting analgesics with multimodal analgesia may help preserve the potential benefits of remifentanil while maintaining adequate postoperative pain control.

4
An interpretable, formally verified point-of-care ultrasound risk equation for difficult videolaryngoscopy: development and internal validation

Oyarzun-Silva, R. A.; Hernandez-Hernandez, P.; Fernandez-Vaquero, M. A.; De Luis-Cabezon, N.

2026-09-02 anesthesia 10.64898/2026.08.28.26361621 medRxiv
Top 0.1%
19.4%
Show abstract

Background. Videolaryngoscopy still requires adjuncts or hyperangulated rescue in a clinically important minority, and bedside screening discriminates modestly. Point-of-care ultrasound (POCUS) of the anterior airway is a promising alternative, but existing prediction models are opaque or assume a pre-specified functional form. We developed and internally validated a parsimonious, fully disclosed POCUS risk equation whose form is recovered from data and whose structural properties are machine-checked by formal proof - to our knowledge the first formally verified clinical risk predictor - following TRIPOD+AI 2024. Methods. In a prospective single-centre, single-operator cohort of 259 adults undergoing elective videolaryngoscopy (no-Easy airway 68/259, 26.3%), Sequentially Thresholded Least Squares with bootstrap stability selection (B=300) screened a 71-term library of nine POCUS features and retained a seven-term logistic equation; a two-term bootstrap-stable model was pre-specified as robustness analysis. Internal validation used 5x10 repeated cross-validation plus temporal and device hold-outs, with pre-specified overfitting and optimism assessments. Five behavioural properties of the deployed equation were machine-checked in Lean 4. Results. Two interactions met the |c|/sigma_c>2 stability criterion: skin-to-epiglottis x skin-to-hyoid-bone distance and tongue volume x sagittal tongue area. The seven-term equation reached a 5x10 cross-validated C-statistic of 0.966 (optimism-corrected 0.968) and held across temporal and device hold-outs (0.94-0.97). Calibration-in-the-large matched prevalence, with cross-validated slope 0.90 attenuating to 0.625 out-of-time; standard recalibration restored 0.92 without loss of discrimination. The pre-specified two-term robustness model reproduced this performance (C-statistic 0.964-0.968; events-per-parameter 34; shrinkage 0.99), confirming the result is not an artefact of the screening stage. Net benefit over a clinical baseline was positive across 10-50% thresholds. All five Lean 4 theorems compiled without sorry. Conclusions. A sparse, formally verified POCUS equation predicts difficult videolaryngoscopy with high internally validated discrimination and quantified, modest overfitting. Because the equation was developed in a single-operator cohort and its inputs are operator-dependent, external validation requires prior harmonisation of the measurement protocol and operator credentialing.

5
The effect of high-dose glucocorticoids on opioid consumption in the first 24 hours after elective hip and knee arthroplasty: A natural experiment study of 47,317 surgeries in Eastern Denmark

Laigaard, J.; Moeller, M. O.; Olsen, M. H.; Overgaard, S.; Mathiesen, O.; Karlsen, A. P. H.

2026-09-02 pain medicine 10.64898/2026.08.31.26361793 medRxiv
Top 0.1%
13.9%
Show abstract

Background: In Denmark, perioperative high-dose glucocorticoid treatment were step-wisely implemented for total hip arthroplasty (THA), total knee arthroplasty (TKA), and unicompartmental knee arthroplasty (UKA). We aimed to estimate the effect of a single high dose of glucocorticoids on opioid consumption following primary THA, TKA, and UKA. Methods: This was a prespecified analysis of a multicenter natural experiment using electronic health record data. We included elective THA, TKA, or UKA surgeries performed in Eastern Denmark from 2017-2025. At each center, surgeries before implementation of high-dose glucocorticoids served as controls, whereas surgeries after implementation comprised the intervention group. The primary outcome was the between-group difference in cumulative 0-24h opioid consumption, which included preemptive end-of-surgery doses. The predefined minimal important difference was set at 5 mg IV morphine equivalents. Secondary outcomes were maximum 0-10 numerical rating scale (NRS) pain score and incidence of opioid-related adverse events within 24 hours, hospital length of stay, and days alive and out of hospital at 30 days. Results: A total of 47,317 surgeries performed at nine centers were analyzed: 13,010 controls and 34,307 in the intervention group. During the study period, five centers implemented high-dose glucocorticoids for THA patients, two for TKA/UKA patients. High-dose glucocorticoids were administered to 6% of patients before implementation versus 92% after. High-dose glucocorticoids resulted in a mean reduction of 3.8 mg intravenous (IV) morphine equivalents (95% CI 3.3;4.3). The intervention also reduced the maximum 0-24h NRS pain score by 0.8 points (99% CI 0.7;0.9), but there was no difference in adverse events, length of stay, or days alive and out of hospital. Conclusions: Implementation of high-dose glucocorticoids reduced 0-24-hour opioid consumption by 3.8 mg IV morphine equivalents after elective hip and knee arthroplasty. This difference was below the prespecified minimal important difference threshold. Online registration: https://doi.org/10.1101/2025.11.11.25339982

6
Effects of Opioid-free Anaesthesia on Postoperative Delirium after Gastrointestinal Surgery in Frail Elderly Patients: A Study Protocol for A Single-centre, Prospective, Randomized Controlled Trial

Liu, Q.; Yang, X.; Zhang, Q.; Zhang, M.; Wu, J.; Du, Y.; Li, Y.; Chen, L.; Gao, X.; Feng, Y.; Song, S.; Sun, X.; Li, Z.; Cheng, L.; Li, Y.; Liu, M.; Sun, Y.

2026-08-13 anesthesia 10.64898/2026.08.12.26360246 medRxiv
Top 0.1%
10.3%
Show abstract

Introduction: The incidence of postoperative delirium (POD) is high in frail elderly patients who have undergone gastrointestinal surgery, and POD significantly increases the risk of complications and medical burden. Opioid-free anaesthesia (OFA) involves a multimodal analgesic strategy, which may help to reduce the risk of POD. However, relevant studies focusing on frail elderly patients are still limited. This study aims to investigate the effect of OFA on the occurrence of POD in frail elderly patients after gastrointestinal surgery. Methods: This single-centre, prospective, randomized controlled trial (RCT) will be conducted at the First Affiliated Hospital of Shandong First Medical University, China. A total of 44 frail elderly patients aged 65 years or older who plan to undergo elective gastrointestinal surgery (modified frailty index (mFI > 0.27) will be randomly assigned to either the OFA group (receiving dexmedetomidine, esmolol, and ketamine) or the opioid-based anaesthesia (OBA) group. The primary outcome is the incidence of POD within 7 days after surgery or at discharge. Secondary outcome measures include the perioperative stress response, inflammation, intraoperative haemodynamics, postoperative 30-day all-cause mortality, intraoperative haemodynamic changes, 15-item quality of recovery (QoR-15), and postoperative complications during hospitalization. This study focuses on frail elderly individuals (a high-risk population) and aims to investigate the potential benefits of the OFA strategy in reducing the incidence of POD by reducing exposure to opioids through multimodal analgesia. If positive results are obtained in this study, they may provide new evidence for optimizing the perioperative management of such patients. This study is a single-centre, prospective RCT, and the results can provide preliminary evidence for subsequent studies to be performed on a larger scale. Discussion: This study focuses on frail elderly individuals (a high-risk population) and aims to investigate the potential benefits of the OFA strategy in reducing the incidence of POD by reducing exposure to opioids through multimodal analgesia. If positive results are obtained in this study, they may provide new evidence for optimizing the perioperative management of such patients. This study is a single-centre, prospective RCT, and the results can provide preliminary evidence for subsequent studies to be performed on a larger scale. Trial registration: NCT07603596.

7
Pain and Pain Sensitivity Assessments in the Acute to Chronic Pain Signatures (A2CPS) Program

Frey-Law, L. A.; Berardi, G.; Ansari, B.; Liu, Y.; Satpathy-Horton, B.; Sluka, K. A.; Vance, C. G.; Dailey, D. L.; McCarthy, R. J.; Wager, T. D.; Lindquist, M. A.; Harte, S. E.; A2CPS Consortium,

2026-08-17 pain medicine 10.64898/2026.08.14.26360457 medRxiv
Top 0.1%
5.4%
Show abstract

The Acute to Chronic Pain Signatures (A2CPS) project is a large, multisite, longitudinal observational study designed to identify biomarkers that predict the transition from acute to chronic pain following surgery in more than 2200 patients. Two participant cohorts were recruited before undergoing either knee arthroplasty or thoracic surgery. A unique feature of this study is its comprehensive evaluation of pain, including evoked and recall pain measures collected at baseline, 6-weeks, and 3-months following surgery, in addition to the primary pain outcome assessed remotely at 6 months. This paper describes the acquisition, quality control procedures, and available pain and pain sensitivity variables included in the A2CPS study. Self-report pain assessments include surgical site (i.e., index) pain intensity, pain interference and quality, spatial distribution of pain using body maps, and pain-related dysfunction specific to each cohort. Quantitative sensory testing yielded evoked pain sensitivity data including pressure pain thresholds, temporal summation of pain, dynamic mechanical allodynia, and conditioned pain modulation at both index and common sites across cohorts. Movement-evoked pain was assessed for each cohort using relevant functional tasks (knee: 10m walk and five-time-sit-to-stand tests, thoracic: deep breathing and coughing). Using baseline data from release v2.1.0, comprising approximately 1,400 participants, we evaluated interrelationships among pain variables. Overall, the A2CPS pain and pain sensitivity data provide a robust, comprehensive set of variables that supports the study goal of uncovering predictive biomarkers of post-operative chronic pain and enables broader exploration relative to other study outcomes, including imaging, psychosocial, and omics data.

8
The dynamics of arterial pressure itself predict intraoperative hypotension beyond its current value: an interpretable additive model validated in 3,069 external patients under a selection-bias-resistant protocol

Oyarzun, R.; Hernandez, P.

2026-08-31 anesthesia 10.64898/2026.08.26.26361468 medRxiv
Top 0.1%
5.0%
Show abstract

Background. Whether predictors of intraoperative hypotension (IOH) add information beyond the mean arterial pressure (MAP) already displayed on the monitor is contested: selection bias in common evaluation designs inflates apparent performance, and the field has called for comparisons against simple MAP-based references under bias-resistant protocols. Existing predictors also depend on proprietary waveform analysis or pulse-contour monitors, restricting both deployment and external validation. Methods. Using 807 non-cardiac surgery patients from the open VitalDB database, we derived an additive gradient boosting model (one split per tree: a learned shape function per variable, no interactions) from three variables computable from an arterial line alone: current MAP, its drift from the patient's own 20-minute baseline, and the growth of its rolling variance (critical slowing down). Evaluation used patient-level 5-fold cross-validation under a strict protocol - exclusion of the 65-75 mmHg grey zone and of all samples already hypotensive at prediction time - with MAP alone (same learner class) as comparator. The frozen model was then validated, without any refitting, on an independent cohort from another continent (MOVER, University of California Irvine) following a pre-registered plan sealed before external data access. Results. In development the pressure-only model reached AUROC 0.907 vs. 0.884 for MAP alone (Delta AUROC +0.023, 95% CI +0.017 to +0.029) at 5 min, with +0.031 and +0.032 at 10 and 15 min, and good calibration (Brier skill +0.418 vs. prevalence). In external validation on 3,069 patients (442,194 samples, 1-minute charting, event prevalence 5.8%), the advantage not only transferred but was larger than in development: AUROC 0.696 vs. 0.638, Delta AUROC +0.058 (95% CI +0.051 to +0.064), meeting both pre-registered gates. Discrimination transferred; calibration did not (external Brier skill -0.014), requiring local recalibration. In the unrestricted scenario, where samples already at threshold are retained, the advantage collapsed (+0.007), reproducing the selection effect this paper documents. A secondary model adding pulse-contour cardiac output and stroke volume variation improved development discrimination further (Delta AUROC +0.035) but could be externally validated in only 39 patients, because those signals are rarely recorded. Conclusions. The dynamics of arterial pressure itself - drift from a patient-specific baseline and variance growth - carry predictive information beyond its current value, in a fully interpretable additive model that requires only an arterial line, no waveform access and no proprietary hardware. The advantage is confirmed in a pre-registered frozen-model external validation of over three thousand patients, and is largest at coarse recording cadence, where instantaneous pressure is least informative.

9
The Plateau Hemoglobin Paradox: Reversed Effect of Hemoglobin on Surgical Outcomes by Oxygen Saturation Strata at High Altitude

Dang, Z.; Dan, J.; Su, W.; Ren, G.; Wang, Z.; Ma, Y.; Li, S.; Ji, D.; Li, L.; Gao, J.

2026-08-23 surgery 10.64898/2026.08.19.26360786 medRxiv
Top 0.1%
4.3%
Show abstract

Background: Hemoglobin (Hb) elevation is the hallmark of high-altitude adaptation, yet its effect on surgical outcomes may depend on arterial oxygen saturation (SpO2)--previously uninvestigated. Objectives: To explore whether preoperative Hb effect on postoperative length of stay (LOS) after laparoscopic cholecystectomy (LC) reverses across SpO2 strata. Methods: Retrospective single-center cohort of 612 adults undergoing elective LC (2018-2023) at Qinghai Red Cross Hospital, Xining, China (2260 m). Exposure: preoperative Hb (82-233 g/L) and SpO2 (86%-99%), stratified as low (<93%), mid (93%-95%), high (>=96%). Primary analysis: multivariable linear regression with Hb x SpO2 interaction, adjusted for BMI, age, sex, season. Results: Among 612 patients (65.8% female; mean age 43.5 [11.9] years; mean Hb 151.4 [20.7] g/L; mean SpO2 94.6% [2.3%]), the Hb x SpO2 interaction was significant (beta = -0.0095; P = .009). Hb effect reversed: in SpO2 >=93%, each 1 g/L Hb prolonged LOS by 0.003 days (P = .079); in SpO2 <93%, each 1 g/L reduced LOS by 0.006 days. In mid-SpO2 stratum (n = 251), Hb >=180 g/L had longer LOS (1.88 vs 1.62 days; P = .001; d = 0.54). Five computational robustness analyses confirmed the interaction (leave-one-out: 100% P < .05 across 612 iterations). Conclusions: In this exploratory cohort, we observed an SpO2-dependent reversal of the Hb effect on postoperative LOS, designated the "Plateau Hemoglobin Paradox." Given single-center design and achieved power of 0.754, findings require replication. If replicated, this pattern may inform future perioperative risk stratification at high altitude.

10
Patient-Specific Adaptations in ERAS for High-Altitude Laparoscopic Cholecystectomy: The PAERS Hypothesis

Dang, Z.; Dan, J.; Su, W.; Ren, G.; Wang, Z.; Ma, Y.; Li, S.; Ji, D.; Li, L.; Gao, J.

2026-08-25 surgery 10.64898/2026.08.21.26360905 medRxiv
Top 0.1%
3.5%
Show abstract

Background: ERAS protocols reduce hospital stay by 1.88 days and complications by 29% globally, but their one-size-fits-all paradigm, validated at sea level, may fail at high altitude where chronic hypoxia and population-specific genetic adaptations remodel baseline physiology. No study has quantified ERAS effect weight shifts at high altitude or proposed a theoretical model to explain the gap. Objectives: To evaluate three dimensions of plateau ERAS remodeling: (i) risk factor weight shift, (ii) traditional marker failure, (iii) genetic background modification, and propose the PAERS (Plateau Adaptation-ERAS Remodeling Syndrome) risk stratification model tailored to altitude. Methods: Retrospective cohort of 612 adults undergoing elective laparoscopic cholecystectomy (2018-2023) at Qinghai Red Cross Hospital (2260 m). Three analytical tiers: (1) multivariable regression comparing risk factor coefficients against plain-altitude benchmarks; (2) restricted cubic spline and interaction modeling for Hb, SpO2, and LOS; (3) inferential genetic modifier analysis using population-level EPAS1 carrier rates. Primary outcomes: LOS and complication rate. Results: Three-dimensional shift was observed: (1) Weight Remodeling: BMI replaced sex as primary risk factor (OR = 1.86, P < .001), surgeon variability amplified (F = 6.33 vs plain benchmark 2-4, an ~58% increase in F-statistic ratio, P < .001); (2) Marker Failure: Hb showed J-type relationship with LOS (Hb x SpO2 interaction beta = -0.0095, P = .009), with effect reversal across SpO2 strata (Plateau Hemoglobin Paradox); (3) Genetic Modification (population-level inference): ~70% EPAS1 carrier rate (range 57-85% across studies) suggests HIF-2alpha pathway is a baseline modifier that must be accounted for. Three falsifiable predictions were proposed. Conclusions: High-altitude ERAS faces three challenges: effect weight remodeling, biomarker failure, and genetic background calibration. The PAERS hypothesis proposes an integrated risk stratification model, shifting from one-size-fits-all to altitude-aware, patient-specific protocols.

11
Biobehavioral pain profiling of minoritized adults with chronic widespread pain and clinical obesity before and after bariatric surgery: study protocol for a longitudinal, observational cohort study

Merriwether, E. N.; Maqsood, M. N.; Vanegas, S. M.; Em, S.; Perez, N.; Parikh, M.; Ruiz-Guerenabarrena, B.; Humala-Martinez, C.; Lopez, B.; Fillingim, R. B.; Jay, M.

2026-08-06 pain medicine 10.64898/2026.08.04.26359660 medRxiv
Top 0.1%
3.3%
Show abstract

Chronic widespread pain (CWP) is highly prevalent among minoritized adults with clinical obesity, and symptom management is challenging. Weight loss via bariatric surgery is often recommended to improve musculoskeletal pain. However, there is significant variation in pain trajectories following bariatric surgery, and the impact of weight loss on movement-evoked pain is largely unknown. The current study aims to systematically characterize and quantify longitudinal changes in pain at rest and movement-evoked pain up to 6 months post-surgery, and to determine whether pain modulatory mechanisms, joint motion, and mechanical loading biosignatures mediate the relationship between weight loss and pain change. This study protocol details the research methodologies and procedures for a prospective observational cohort study of 60 individuals undergoing bariatric surgery for weight loss. Participants will complete questionnaires, anthropometric measurements, clinical and experimental pain testing, functional testing, and a standardized movement testing battery to assess joint motion and mechanical loading using camera-based motion capture before and at 3 and 6 months post-bariatric surgery. Generalized linear mixed models to assess the significance of changes in PAR, MEP, and all patient-reported outcome measures. Reduced models will treat the main effect of time as a fixed factor, and intra-individual repeated measures as random effects. Ethics and dissemination: This study protocol has been registered as an observational study with ClinicalTrials.gov (NCT0675386) in the United States and has been approved by the NYU Langone Health Institutional Review Board (IRB#: i21-01652) and the New York City Health + Hospitals/Bellevue Research Office (Bellevue Study ID #: STUDY00003739). Study results will be published in peer-reviewed journals and presented at national and international conferences and community events.

12
Procedure-Specific Long-Term Thromboembolic Risk Associated With Postoperative Atrial Fibrillation After Cardiac Surgery: A Systematic Review and Meta-Analysis

Ullah, A.

2026-08-25 cardiovascular medicine 10.64898/2026.08.23.26361121 medRxiv
Top 0.1%
2.4%
Show abstract

Postoperative atrial fibrillation (POAF) is a frequent complication following cardiac surgery and has been associated with an increased risk of thromboembolic events. However, cardiac surgical populations are heterogeneous, and the long-term thromboembolic implications of POAF may differ according to the index surgical procedure. This systematic review and meta-analysis evaluated the procedure-specific association between POAF and long-term thromboembolic outcomes after adult cardiac surgery, with particular emphasis on coronary artery bypass grafting (CABG) and isolated valve surgery. PubMed and Scopus were searched from database inception through August 3, 2026. Studies reporting long-term thromboembolic outcomes in patients with new-onset POAF compared with patients without POAF were evaluated, with eligible evidence classified according to the index surgical procedure. Four observational studies were included in the primary quantitative synthesis, with two studies contributing to the CABG analysis and two to the isolated valve-surgery analysis. Adjusted hazard ratios (HRs) were pooled separately by procedure using inverse-variance methods, and a formal between-subgroup interaction test was performed. Following CABG, POAF was associated with an increased long-term thromboembolic hazard (pooled HR 1.147, 95% CI 1.053-1.249; I^2=0%). A stronger association was observed following isolated valve surgery (pooled HR 1.362, 95% CI 1.181-1.573; I^2=0%). The between-subgroup interaction was statistically significant ({chi}^2=4.10, P=0.043), providing exploratory evidence that the magnitude of the association may differ according to surgical procedure. These findings suggest that the long-term thromboembolic implications of POAF may not be uniform across cardiac surgical populations. However, because only two studies contributed to each procedure subgroup and the available evidence was observational, the interaction should be considered hypothesis-generating. Further adequately powered studies with standardized outcome definitions and procedure-specific reporting are required to confirm these findings and determine their implications for long-term risk stratification and anticoagulation strategies.

13
Patient and Surgeon Willingness to Participate in a Randomized Trial of Surgery Versus Observation for Mild Cervical Spondylotic Myelopathy: A Cross-Sectional Survey Study

Arkam, F.; Zeng, X.; Goldstein, E.; Badhiwala, J.; Chan, A. K.; Cheng, A. L.; Chou, D.; Colman, M.; Ghogawala, Z.; Godzik, J.; Kelly, M. P.; Mroz, T. E.; Orosz, L.; Park, P.; Patel, A. A.; Potts, E. A.; Schechtman, K. B.; Steinmetz, M. P.; Xiong, G. X.; Yakdan, S.; Zhang, L.; Neuman, B. J.; Sasso, R. C.; Rhee, J.; Ray, W. Z.; Politi, M. C.; Greenberg, J. K.

2026-08-21 orthopedics 10.64898/2026.08.18.26360719 medRxiv
Top 0.1%
2.3%
Show abstract

Background Cervical spondylotic myelopathy (CSM) is the most common cause of nontraumatic spinal cord dysfunction in adults. For mild disease, guidelines recommend shared decision-making between surgery and structured rehabilitation on the basis of clinical equipoise, yet no comparative effectiveness study has reported outcomes in this population. Whether a randomized trial is feasible is unknown. Methods We conducted two cross-sectional surveys between December 2025 and July 2026: one of patients with surgeon-confirmed CSM recruited from academic outpatient spine clinics, and one of practicing neurosurgical and orthopedic spine surgeons. Respondents rated willingness to participate in (1) a randomized trial of early surgery versus observation and (2) a prospective observational study in which treatment was patient-selected. Responses of likely or very likely were classified as willing. Groups were compared using Fisher exact tests, designs within respondents using exact McNemar tests, and predictors using univariable logistic regression. Results Fifty-four patients and 52 surgeons completed the surveys. Patients were markedly less willing than surgeons to accept randomization (15 of 54, 27.8% versus 44 of 52, 84.6%; p < 0.001). Both groups accepted the observational design (39 of 54, 72.2% versus 51 of 52, 98.1%; p < 0.001), and 26 of 39 patients unwilling to be randomized were willing to enroll in an observational study (p < 0.001). Willingness to be randomized did not differ across mJOA severity (mild 30.4%, moderate 25.0%, severe 27.3%; p = 0.93). Among patients declining randomization, 85.2% cited a wish to retain control over treatment, whereas fear of surgery was cited by one respondent. Forty-five surgeons (86.5%) considered both surgery and observation reasonable, and preference was divided (46.2% favoring early surgery, 48.1% favoring initial observation). Conclusions Surgeons report equipoise and high willingness to randomize, but most patients would decline random allocation, citing a wish to retain treatment choice rather than fear or distrust. A prospective observational study appears the more feasible route to comparative evidence in mild CSM. Feasibility assessments restricted to clinicians may substantially overestimate attainable accrual.

14
Distinct contributions of post-traumatic stress and working memory to affective and sensory dimensions of chronic pain, with pain modulation as a shared mechanism

Veinot, J.; Hashmi, J. A.

2026-08-19 Neuroscience 10.64898/2026.08.14.744859 medRxiv
Top 0.1%
1.8%
Show abstract

Chronic pain is highly heterogeneous, with individuals varying substantially in symptoms. pain severity, disability, affective distress, cognitive functioning, and trauma-related symptoms. This study examined whether working memory, post-traumatic stress symptoms (PTSS), trauma exposure, and pain modulation explain distinct or shared dimensions of chronic pain variability. Individuals with chronic pain completed clinical, cognitive, trauma-related, and behavioural pain modulation measures, as well as resting-state functional magnetic resonance imaging. Multivariate regressions were used to determine whether working memory, PTSS, trauma exposure, and pain modulation independently predicted chronic pain outcomes. Principal component analysis was used to identify latent dimensions of chronic pain, and mediation analyses tested whether behavioural pain modulation explained relationships between dlPFC to vlPAG resting-state functional connectivity and clinical pain outcomes. PTSS independently predicted affective outcomes, including depression, state anxiety, and trait anxiety, whereas working memory independently predicted pain severity and pain interference. Trauma exposure was associated with greater PTSS and poorer working memory, but did not independently predict core pain outcomes after accounting for these more proximal factors. Principal component analysis identified partially distinct affective and sensory-disability dimensions, while trauma exposure loaded primarily on a separate component characterized by greater PTSS and poorer working memory. Behavioural pain modulation showed broader relationships across symptom dimensions and was associated with dlPFC to vlPAG connectivity. Exploratory mediation analyses demonstrated that pain modulation mediated relationships between dlPFC to vlPAG connectivity and both pain severity and affective distress. These findings support an integrated model where PTSS and working memory are more proximal predictors of affect and severity respectively, and trauma exposure represents a more distal vulnerability factor that predicts both. Thus, pain modulation represents a shared mechanism linking cortico-brainstem connectivity to chronic pain intensity and affect. These variables need further testing for phenotyping people with chronic pain based on their specific clinical needs.

15
SOFA-2 reclassifies multiorgan dysfunction syndrome in major trauma patients

Krishna, A.; Rosetto, A.; Brohi, K.; Vulliamy, P.; Cole, E.

2026-08-07 intensive care and critical care medicine 10.64898/2026.08.05.26359771 medRxiv
Top 0.2%
1.7%
Show abstract

Objective We aimed to evaluate the performance of the recently updated Sequential Organ Failure Assessment Score-2 (SOFA-2) on organ dysfunction classification and prognostication compared to SOFA-1 in critically injured trauma patients. Methods Adult trauma patients admitted to critical care at four urban Major Trauma Centres between 2011 and 2024 were included. Daily organ dysfunction scoring was performed using SOFA-1 and SOFA-2 until death or discharge. The primary outcome was MODS, defined as SOFA score [&ge;]6. Results In 2162 severely injured patients (median Injury Severity Score 25 [IQR, 17-34]), SOFA-2 reduced the proportion of patients classified as having MODS compared with SOFA-1 (61.6% vs 68.5%, p<0.001). SOFA-2 scores on the first day after admission were lower than SOFA-1 (median 6 [IQR, 3-8] vs 7 [IQR, 4-10], p<0.001), driven predominantly by lower respiratory and cardiovascular scoring. Critical care mortality in trauma patients was increased in respiratory, cardiovascular and renal components of SOFA-2 at the higher ends of the scores, consistent with the aims of the SOFA-2 reclassification. A group of 159 severely injured patients (7.3%) classified as MODS by SOFA-1 were reclassified to no-MODS by SOFA-2. Despite this reclassification, these patients had substantially higher ICU mortality (7.5% vs 0.7%, p<0.01), greater ventilator and vasopressor requirements, and longer hospital stays than patients classified as no-MODS by both systems. Conclusions SOFA-2 reduces MODS prevalence in severely injured patients and changes organ dysfunction classification, with lower rates of severe respiratory and cardiovascular dysfunction. This represents an important update in trauma MODS measurement and has implications for future trauma trial design. However SOFA-2 reclassification generates a small cohort a small but clinically significant group with occult MODS that warrants further evaluation in severely injured trauma patients.

16
Beyond Length of Stay: Patient and Carer Perspectives on Virtual Hospital Pathways Following Colorectal Surgery

Reza, L.; Arbai, Z.; Ward, H.; Payne, L.; Kinross, J.; Patel, V.

2026-08-27 surgery 10.64898/2026.08.24.26361282 medRxiv
Top 0.2%
1.5%
Show abstract

Background Virtual hospital (VH) pathways support early discharge through remote monitoring, but limited evidence has hindered implementation in colorectal surgery. This study aimed to define patient- and carer-relevant outcomes and experiences of VH following colorectal surgery. Methodology A patient and public involvement and engagement (PPIE) consultation was conducted with 8 participants (7 patients, 1 carer; 4 women, 4 men) who had experienced VH following bowel resection at a high-volume robotic unit. Purposive sampling ensured that 50% of participants had experienced readmission. The 90-minute session was delivered via Microsoft Teams. Data were analysed using reflexive thematic analysis. Results Seven themes were identified: readmission, remote monitoring, carer burden, recovery, equity, readiness for discharge, and information delivery. Patients supported early discharge when remote monitoring enabled timely detection of complications and readmission pathways were efficient. Readmission was not perceived as failure but as appropriate escalation. Dissatisfaction with readmission was related to delays in emergency care. Remote monitoring provided psychological safety, with patients feeling held at home. Carers assumed substantial, often unrecognised, quasi-clinical roles. Recovery was defined by return to function rather than length of stay. Equity concerns were evident, with VH favouring those with adequate support at home, digital literacy, and language proficiency. Discharge readiness was both clinical and psychological. Information delivery at discharge was often poorly retained and requires reinforcement preoperatively at every encounter with patients and carers. Conclusions VH pathways are acceptable and valued. Readmission is a marker of system responsiveness rather than failure of early discharge on VH. Psychological preparedness, carer support, and equitable access are critical to successful and scalable implementation of early discharge using a virtual hospital.

17
Combination spinal cord stimulation at different frequencies produces sustained pain relief with immune activation

Huh, Y.; Song, S.; Chen, T.; Zhang, T.; Hershey, B.; Esteller, R.; Ji, R.-R.

2026-08-12 neuroscience 10.64898/2026.08.06.742589 medRxiv
Top 0.2%
1.5%
Show abstract

Spinal cord stimulation (SCS) is an established therapy for neuropathic pain, typically delivered at either low (60 Hz) or high (1 kHz) frequencies, with analgesic effects largely dependent on active stimulation. Here, we investigated whether combined-frequency SCS produces sustained analgesia beyond stimulation periods and explored the underlying mechanisms. Using a spared nerve injury (SNI) model in both rats and mice, we applied dual-frequency SCS (60 Hz + 1 kHz). This paradigm produced robust reversal of mechanical allodynia during stimulation and, notably, a progressive and long-lasting analgesic effect that persisted for days to weeks after stimulation cessation. RNA sequencing revealed pronounced immune-related transcriptional changes in the spinal cord, including upregulation of innate immune, pro-resolution, and neutrophil-associated pathways. Functional studies demonstrated that neutrophil depletion attenuated SCS-induced analgesia, whereas intrathecal S100A8 treatment mimicked therapeutic effects via CD69/SOCS3 signaling. These findings identify dual-frequency SCS as a promising strategy to prolong analgesia and highlight a critical role for neuroimmune modulation in sustained pain relief. HighlightsO_LICombined-frequency, not single-frequency SCS, sustains analgesia during washout C_LIO_LICombination SCS induces robust immune activation in spinal cord and DRG C_LIO_LICombination SCS increases spinal perfusion and promotes neutrophil recruitment C_LIO_LINeutrophil signaling contributes to sustained SCS analgesia C_LI

18
Targeted Pulsed Radio Frequency (PRF) Stimulation in the Management of Diabetic Peripheral Neuropathy: A Randomized, Single-Blind, Placebo-Controlled Trial

Linde, L. D.; Berger, P. P.; Landau, S. S.; Libhaber, E.; Potgieter, P.; van Blerk, P.; Birkill, C. F.

2026-08-10 pain medicine 10.64898/2026.08.07.26359945 medRxiv
Top 0.2%
1.5%
Show abstract

Objective: To evaluate the clinical efficacy of non-invasive electrical pulsed radiofrequency (PRF) stimulation on diagnostic thresholds and subjective pain in chronic, pedal diabetic peripheral neuropathy (DPN). Methods: A randomized, single-blind, placebo-controlled trial (ClinicalTrials.gov: NCT07725419) enrolled 92 patients with pedal DPN naive to PRF and scoring [&ge;] 4/10 on the Douleur Neuropathique 4 (DN4) test. Participants received either active PRF stimulation (n = 46) or a non-stimulating placebo (n = 46) applied bilaterally to the sciatic nerve in the popliteal fossa for 10 minutes per limb, once weekly for three weeks. The primary outcome was clinical neuropathic resolution (DN4 < 4). Secondary outcomes included subjective pain tracking via the Brief Pain Inventory-Short Form (BPI-SF) Worst Pain scale over a 6-month follow-up window. Missing data were handled via Non-Responder Imputation (NRI). Longitudinal continuous trajectories were modeled using Linear Mixed-Effects Models (LMMs) adjusted for age, gender, and baseline medication use. Results: In the Intention-to-Treat population (N = 92), a significant diagnostic responder effect occurred at 3 months, with 39.1% of active patients dropping below the diagnostic threshold for neuropathy (DN4 < 4) versus 19.6% of placebo controls (p = 0.039). For subjective pain, 47.7% of active patients achieved a Minimally Clinically Important Difference ([&ge;] 3-point reduction) in BPI Worst Pain at 1 month compared to 19.4% of placebo controls (p = 0.008). Multivariable logistic regression identified active treatment as a significant independent predictor of clinical response (Adjusted OR = 4.86; 95% CI: 1.56 to 17.53; p = 0.010). Continuous LMM tracking confirmed a statistically significant treatment-by-timepoint interaction for BPI Worst Pain at 1 month (p = 0.046). Conclusion: A brief, three-week course of non-invasive PRF stimulation serves as a safe, effective, non-pharmacological adjunct that aids in managing the diagnostic presentation of neuropathic pain and mitigates worst pain experiences in patients suffering from pedal DPN.

19
Sub-Analysis of a Randomized Controlled Trial of Neuromuscular Electrostimulation of the Common Peroneal Nerve after Forefoot Surgery

Piftor, A.-M.; Bain, D. S.; Day, K.

2026-08-24 orthopedics 10.64898/2026.08.21.26361007 medRxiv
Top 0.2%
1.2%
Show abstract

Gaps remain in the evidence base for postoperative management following forefoot surgery. A recent randomized controlled trial (ClinicalTrials.gov NCT04927234) demonstrated improved outcomes with intermittent one Hertz (Hz) neuromuscular electrical stimulation (NMES) of the common peroneal nerve. This sub-analysis evaluates its effect in patients undergoing forefoot surgery. Forty-two patients undergoing forefoot procedures were included; 26 received NMES plus standard of care (SOC) and 16 received SOC alone. Wound healing was assessed at 14 days. Edema was measured using the figure-of-eight (FO8) method. Patient-reported outcomes were assessed using the Manchester-Oxford Foot Questionnaire (MOXFQ). At 14 days, complete wound healing occurred in 77% of patients receiving NMES plus SOC compared with 40% in the SOC group (p<0.05). Edema reduction was significantly greater in the NMES group, with a 74% relative reduction compared with SOC (p=0.02). Intermittent one Hz NMES of the common peroneal nerve was associated with improved wound healing and reduced postoperative edema following forefoot surgery.

20
Asthma Exacerbations: Integrative Analysis of miRNA Activity Using Single-Cell Transcriptomics

Hadikhani, P.; Yan, X.; Chupp, G. L.; Ban, G. Y.; Piparia, S.; McGeachie, M.; Sharma, R.; Weiss, S. T.; Laurent, L. C.; Kho, A. T.; Tantisira, K. G.

2026-08-06 bioinformatics 10.64898/2026.07.31.741637 medRxiv
Top 0.2%
1.1%
Show abstract

BackgroundAsthma exacerbations are caused by dysregulated cellular interactions between airway and immune cell populations. Circulating microRNAs (miRNAs) are potential biomarkers for asthma exacerbations; however, their target airway cells remain poorly defined. ObjectiveTo identify the cell types that are regulated by the circulating microRNAs linked to asthma exacerbations and the extent to which the cells are regulated by miRNAs. MethodsWe integrated a curated panel of exacerbation-associated circulating miRNAs with single-cell RNA sequencing (scRNA-seq) profiles from induced sputum of 16 asthma patients and 8 healthy controls. Experimentally validated miRNA-target interactions were combined with cell-type-specific differential expression. Elastic Net regression and SHAP analysis quantified gene-level regulatory contributions, yielding a composite Regulation Strength metric. Findings were validated against four independent GEO datasets. ResultsImmune cells, including monocytes, dendritic cells, and macrophages, demonstrated the strongest statistically significant miRNA regulatory signals, in contrast to airway epithelial cells.hsa-miR-222-3p showed opposing regulatory effects in mature versus alveolar macrophages, indicating differentiation-state-dependent activity, while B_Plasma cells showed no detectable regulatory effect from any miRNA tested. Independent GEO validation confirmed higher expression of protective miRNAs (hsa-miR-126-3p, hsa-miR-146b-5p) in healthy individuals, consistent with prior CAMP cohort associations. ConclusionCirculating miRNAs show cell-type-specific regulatory activity, strongest in monocytes, dendritic cells, and macrophages. hsa-miR-222-3p showed opposing regulatory directions between macrophage subtypes, while B_Plasma cells showed no effect, validated across independent GEO cohorts.