Post-Traumatic Stress Disorder Is Associated With Increased Emergency Department Services and Similar Rates of Opioid Prescriptions Following Primary Total Hip Arthroplasty: A Propensity Matched Analysis.

BACKGROUND: There is a paucity of literature regarding patients who have post-traumatic stress disorder (PTSD) following primary total hip arthroplasty (THA). The purpose of this study was to compare the rates of postoperative complications, prescriptions, health care utilization, and revision arthroplasty of patients who had PTSD undergoing primary THA against a propensity matched control group of patients who did not have PTSD (NPTSD). METHODS: The TriNetX database was queried to identify PTSD patients undergoing primary THA. Patients were then propensity matched in a 1:1 ratio based on twelve preoperative characteristics to a cohort of NPTSD patients. Postoperative prescriptions and rates of health care utilization were analyzed within 5 days, 14 days, and 1 month postoperatively. Complications were analyzed within one month. Revision arthroplasty rates were analyzed within 1 year and 2 years. RESULTS: A total of 198,560 patients undergoing primary THA were identified. Ultimately, 1,310 PTSD patients were successfully propensity matched to a cohort of 1,310 NPTSD patients. Patients who have PTSD presented to the emergency department at significantly higher rates than NPTSD patients within 14 days and 1 month postoperatively. Within 1 month postoperatively, cohorts were prescribed opioid analgesics at similar rates (P = .709). Patients who had PTSD received more prescriptions per patient compared to NPTSD patients. Patients who had PTSD were also found to have a higher number of total complications per person within 1 month (P = .022). Within 2 years postoperatively, rates of revision hip arthroplasty were comparable between cohorts (P = .912). CONCLUSIONS: Patients who have PTSD experience similar rates of revision hip arthroplasty and opioid prescribing compared to NPTSD patients following primary THA; however, within 1 month postoperatively, emergency department visits were greater in PTSD patients. These findings can help delineate early postoperative education and expectations for patients who have PTSD in contrast to other psychiatric diagnoses.

Variation in optimal hemodynamic atrio-ventricular delay of biventricular pacing with different endocardial left ventricular lead locations using precision hemodynamics.

INTRODUCTION: It is not known whether the optimal atrioventricular (AVopt ) delay varies between left ventricular (LV) pacing site during endocardial biventricular pacing (BiVP) and may therefore needs consideration. METHODS: We assessed the hemodynamic AVopt in patients with chronic heart failure undergoing endocardial LV lead implantation. AVopt was assessed during atrio-BiVP with a "roving LV lead." Up to four locations were studied: mid-lateral wall, mid-septum (or a close alternative), site of greatest hemodynamic improvement, and LV lead implant site. The AVopt was compared to a fixed AV delay of 180 ms. RESULTS: Seventeen patients were included (12 male, aged 66.5 ± 12.8 years, ejection fraction 26 ± 7%, 16 left bundle branch block or high percentage of right ventricular pacing [RVP], QRS duration 167 ± 27 ms). In most locations (62/63), AVopt increased systolic blood pressure during BiVP compared with RVP (relative improvement 6 mmHg, interquartile range [IQR] 4-9 mmHg). Compared to a fixed AV delay, the hemodynamic improvement at AVopt was higher (1 mmHg, IQR 0.2-2.6 mmHg, p < .001). Within most patients (16/17), we observed a difference in AVopt between pacing sites (median paced AVopt 209 ms, IQR 117-250). Within this range, the hemodynamic impact of these differences was small (median loss 0.6 mmHg, IQR 0.1-2.6 mmHg). CONCLUSION: Within a patient, different endocardial LV lead locations have slightly different hemodynamic AVopt which are superior to a fixed AV delay. The hemodynamic consequence of applying an optimum from a different lead location is small.

How robust are recommended waiting times to pacing after cardiac surgery that are derived from observational data?

AIMS: For bradycardic patients after cardiac surgery, it is unknown how long to wait before implanting a permanent pacemaker (PPM). Current recommendations vary and are based on observational studies. This study aims to examine why this variation may exist. METHODS AND RESULTS: We conducted first a study of patients in our institution and second a systematic review of studies examining conduction disturbance and pacing after cardiac surgery. Of 5849 operations over a 6-year period, 103 (1.8%) patients required PPM implantation. Only pacing dependence at implant and time from surgery to implant were associated with 30-day pacing dependence. The only predictor of regression of pacing dependence was time from surgery to implant. We then applied the conventional procedure of receiver operating characteristic (ROC) analysis, seeking an optimal time point for decision-making. This suggested the optimal waiting time was 12.5 days for predicting pacing dependence at 30 days for all patients (area under the ROC curve (AUC) 0.620, P = 0.031) and for predicting regression of pacing dependence in patients who were pacing-dependent at implant (AUC 0.769, P < 0.001). However, our systematic review showed that recommended optimal decision-making time points were strongly correlated with the average implant time point of those individual studies (R = 0.96, P < 0.001). We further conducted modelling which revealed that in any such study, the ROC method is strongly biased to indicate a value near to the median time to implant as optimal. CONCLUSION: When commonly used automated statistical methods are applied to observational data with the aim of defining the optimal time to pacing after cardiac surgery, the suggested answer is likely to be similar to the average time to pacing in that cohort.

Evaluation of Work Efficiency in Structural Firefighters.

ABSTRACT: Langford, EL, Bergstrom, HC, Lanham, S, Eastman, AQ, Best, S, Ma, X, Mason, MR, and Abel, MG. Evaluation of work efficiency in structural firefighters. J Strength Cond Res 37(12): 2457-2466, 2023-To perform occupational tasks safely and effectively, firefighters (FF) must work quickly and consume air provided by the self-contained breathing apparatus (SCBA) efficiently. However, most literature only factors work rate into performance, neglecting the inherent time limitation imposed by the SCBA. The purpose of this article was to (a) evaluate the reliability and variability in a "work efficiency" (WE) performance metric reflective of both work rate and air consumption; (b) explore the relationship between WE and established measures of metabolic strain; and (c) identify fitness, anthropometric, and demographic correlates of WE. About 79 structural FF completed an air consumption drill while breathing through an SCBA. Self-paced work duration and air consumption were entered into the WE equation. A subsample of FF (n = 44) completed another randomized trial while breathing through a portable gas analyzer. Anthropometric and fitness data were collected separately. Correlations were performed between WE vs. fitness, anthropometric, demographic, and metabolic outcomes. Multiple linear regression was used to identify the strongest predictors of WE. WE was reliable (intraclass correlation coefficient = 0.71) and yielded inter-FF variability {0.79 ± 0.25 ([lb·in-2·min]-1) × 104; coefficient of variation = 31.6%}. WE was positively correlated to oxygen consumption (V̇O2) (L·minute-1, mL·kg-1·minute-1) and tidal volume and negatively correlated to V̇E/V̇O2 and respiratory frequency. Height, upper-body endurance, and aerobic endurance were identified as the strongest predictors of WE (adjusted R2 = 0.59, RMSE = 0.16). WE is a reliable and occupationally relevant method to assess FF performance because it accounts for work rate and air consumption. Firefighters may enhance WE through a training intervention focused on improving metabolic tolerance, upper-body endurance, and aerobic endurance.

Individual Patient-reported Activity Levels Before and After Joint Arthroplasty Are Neither Accurate nor Reproducible.

BACKGROUND: Patients often are asked to report walking distances before joint arthroplasty and when discussing their results after surgery, but little evidence demonstrates whether patient responses accurately represent their activity. QUESTIONS/PURPOSES: Are patients accurate in reporting distance walked, when compared with distance measured by an accelerometer, within a 50% margin of error? METHODS: Patients undergoing THA or TKA were recruited over a 16-month period. One hundred twenty-one patients were screened and 66 patients (55%) were enrolled. There were no differences in mean age (p = 0.68), proportion of hips versus knees (p = 0.95), or sex (p = 0.16) between screened and enrolled patients. Each patient wore a FitBit Zip accelerometer for 1 week and was blinded to its measurements. The patients reported their perceived walking distance in miles daily. Data were collected preoperatively and 6 to 8 weeks postoperatively. Responses were normalized against the accelerometer distances and Wilcoxon one-tailed signed-rank testing was performed to compare the mean patient error with a 50% margin of error, our primary endpoint. RESULTS: We found that patients' self-reported walking distances were not accurate. The mean error of reporting was > 50% both preoperatively (p = 0.002) and postoperatively (p < 0.001). The mean magnitude of error was 69% (SD 58%) preoperatively and 93% (SD 86%) postoperatively and increased with time (p = 0.001). CONCLUSIONS: Patients' estimates of daily walking distances differed substantially from those patients' walking distances as recorded by an accelerometer, the accuracy of which has been validated in treadmill tests. Providers should exercise caution when interpreting patient-reported activity levels. LEVEL OF EVIDENCE: Level III, diagnostic study.

The prognostic significance of incomplete revascularization and untreated coronary anatomy following percutaneous coronary intervention: An analysis of 6,755 patients with multivessel disease.

BACKGROUND: More than half of the patients undergoing percutaneous coronary intervention (PCI) have multivessel disease. Whether complete revascularization impacts long-term mortality or whether selected patients or those with specific coronary anatomy benefit from complete revascularization is unclear. METHODS: A total of 14,452 patients underwent PCI between 2004 and 2015 at Harefield Hospital, UK. Of these, 7,076 patients had multivessel disease. We excluded 321 patients with left main-stem stenosis ≥50%, with 6,755 patients included in the analysis (936 patients had complete revascularization). RESULTS: The unadjusted 3-year mortality rates were lower with complete revascularization (10.8% vs 13.1%, P = 0.047). However, multivariable-adjusted analyses indicated that complete revascularization was not independently associated with mortality (HR = 1.01, 95% CI: 0.78-1.31, P = 0.939). These findings were unchanged when addressing measured confounding using propensity-matched analyses (HR = 1.16, 95% CI: 0.81-1.65, P = 0.417) and inverse probability treatment weighted analyses (HR = 1.01, 95% CI: 0.77-1.33, P = 0.950); and unmeasured confounding using instrumental variable analyses (Δ = 0.9%, 95% CI: -2.5%, 4.3%, P = 0.958). There was no association with mortality and untreated LAD disease (HR = 0.92, 95% CI: 0.72-1.17, P = 0.482) and LCx disease (HR = 0.90, 95% CI: 0.74-1.10, P = 0.999). However, untreated proximal LAD disease (HR = 1.23, 95% CI: 1.06-1.51, P = 0.045) and RCA disease (HR = 1.36, 95% CI: 1.08-1.65, P = 0.007) was associated with increased mortality, particularly in patients with ST-elevation acute coronary syndrome (STEACS). CONCLUSIONS: In this study of unselected patients undergoing PCI, complete revascularization did not confer a mortality benefit. However, the presence of untreated proximal LAD and RCA disease was prognostic in patients with STEACS. Thus, complete revascularization may be considered in select patient groups with anatomical subsets of coronary disease.

A Delphi-Based Consensus Statement on the Management of Anticoagulated Patients With Botulinum Toxin for Limb Spasticity.

OBJECTIVE: To create a consensus statement on the considerations for treatment of anticoagulated patients with botulinum toxin A (BoNTA) intramuscular injections for limb spasticity. DESIGN: We used the Delphi method. SETTING: A multiquestion electronic survey. PARTICIPANTS: Canadian physicians (N=39) who use BoNTA injections for spasticity management in their practice. INTERVENTIONS: After the survey was sent, there were e-mail discussions to facilitate an understanding of the issues underlying the responses. Consensus for each question was reached when agreement level was ≥75%. MAIN OUTCOME MEASURES: Not applicable. RESULTS: When injecting BoNTA in anticoagulated patients: (1) BoNTA injections should not be withheld regardless of muscles injected; (2) a 25G or smaller size needle should be used when injecting into the deep leg compartment muscles; (3) international normalized ratio (INR) level should be ≤3.5 when injecting the deep leg compartment muscles; (4) if there are clinical concerns such as history of a fluctuating INR, recent bleeding, excessive or new bruising, then an INR value on the day of injection with point-of-care testing or within the preceding 2-3 days should be taken into consideration when injecting deep compartment muscles; (5) the concern regarding bleeding when using direct oral anticoagulants (DOACs) should be the same as with warfarin (when INR is in the therapeutic range); (6) the dose and scheduling of DOACs should not be altered for the purpose of minimizing the risk of bleeding prior to BoNTA injections. CONCLUSIONS: These consensus statements provide a framework for physicians to consider when injecting BoNTA for spasticity in anticoagulated patients. These consensus statements are not strict guidelines or decision-making steps, but rather an effort to generate common understanding in the absence of evidence in the literature.

Cardiac resynchronization therapy: mechanisms of action and scope for further improvement in cardiac function.

AIMS: Cardiac resynchronization therapy (CRT) may exert its beneficial haemodynamic effect by improving ventricular synchrony and improving atrioventricular (AV) timing. The aim of this study was to establish the relative importance of the mechanisms through which CRT improves cardiac function and explore the potential for additional improvements with improved ventricular resynchronization. METHODS AND RESULTS: We performed simulations using the CircAdapt haemodynamic model and performed haemodynamic measurements while adjusting AV delay, at low and high heart rates, in 87 patients with CRT devices. We assessed QRS duration, presence of fusion, and haemodynamic response. The simulations suggest that intrinsic PR interval and the magnitude of reduction in ventricular activation determine the relative importance of the mechanisms of benefit. For example, if PR interval is 201 ms and LV activation time is reduced by 25 ms (typical for current CRT methods), then AV delay optimization is responsible for 69% of overall improvement. Reducing LV activation time by an additional 25 ms produced an additional 2.6 mmHg increase in blood pressure (30% of effect size observed with current CRT). In the clinical population, ventricular fusion significantly shortened QRS duration (Δ-27 ± 23 ms, P < 0.001) and improved systolic blood pressure (mean 2.5 mmHg increase). Ventricular fusion was present in 69% of patients, yet in 40% of patients with fusion, shortening AV delay (to a delay where fusion was not present) produced the optimal haemodynamic response. CONCLUSIONS: Improving LV preloading by shortening AV delay is an important mechanism through which cardiac function is improved with CRT. There is substantial scope for further improvement if methods for delivering more efficient ventricular resynchronization can be developed. CLINICAL TRIAL REGISTRATION: Our clinical data were obtained from a subpopulation of the British Randomised Controlled Trial of AV and VV Optimisation (BRAVO), which is a registered clinical trial with unique identifier: NCT01258829, https://clinicaltrials.gov.

Anticoagulated Trauma Patients: A Level I Trauma Center's Response to a Growing Geriatric Population.

BACKGROUND: Injured older adults often receive delayed care in the emergency department (ED) because they do not meet criteria for trauma team activation (TTA). This is particularly dangerous for the increasing number of patients taking anticoagulant or antiplatelet (AC/AP) medication at the time of injury. OBJECTIVES: The present study examined improvements in processes of care and triage accuracy when TTA criteria include an escalated response for older anticoagulated patients. METHODS: A retrospective study was performed at a Level I trauma center. The study population (referred to as A55) included patients aged 55 years or older who were taking an AC/AP medication at the time of injury. Study periods included 11 months prior to the criteria change (Phase 1: July 2013-May 2014; n = 107) and 11 months after the change (Phase 2: July 2014-May 2015; n = 211). Differences were assessed with Kruskal-Wallis and chi-squared tests. RESULTS: More A55 patients received a full or limited TTA after criteria were revised (70% vs. 26%, p < 0.001). Undertriage was reduced from 13% to 2% (p < 0.001). The trauma center significantly decreased time to first laboratory result, time to first computed tomography scan, and total time in ED prior to admission for A55 patients arriving from the scene of injury or by private vehicle. CONCLUSION: Criteria that escalated the trauma response for A55 patients led to reductions in undertriage for anticoagulated older adults, as well as more timely mobilization of important clinical resources.

Algorithms to guide ambulance clinicians in the management of emergencies in patients with implanted rotary left ventricular assist devices.

Advances in left ventricular assist device (LVAD) therapy have resulted in increasing numbers of adult LVAD recipients in the community. However, device failure, stroke, bleeding, LVAD thrombosis and systemic infection can be life-threatening emergencies. Currently, four LVAD systems are implanted in six UK transplant centres, each of which provides device-specific information to local emergency services. This has resulted in inconsistent availability and content of information with the risks of delayed or inappropriate decision-making. In order to improve patient safety, a consortium of UK healthcare professionals with expertise in LVADs developed universally applicable prehospital emergency algorithms. Guidance was framed as closely as possible on the standard ABCDE approach to the assessment of critically ill patients.

Intra-Aortic Balloon Pump Counterpulsation in the Post-Resuscitation Period is Associated with Improved Functional Outcomes in Patients Surviving an Out-of-Hospital Cardiac Arrest: Insights from a Dedicated Heart Attack Centre.

BACKGROUND: Despite advances in cardiopulmonary resuscitation, functional survival remains low after out-of-hospital cardiac arrest (OOHCA). Intra-aortic balloon pump (IABP) therapy has recently been shown to augment cerebral blood flow. Whether IABP therapy in the post-resuscitation period improves functional outcomes is unknown. METHODS: We analysed 174 consecutive patients who were successfully resuscitated from an OOHCA between 2011-2013 at Harefield Hospital, London. We analysed functional status at discharge and mortality up to one year. RESULTS: A total of 55 patients (32.1%) received IABP therapy. Comparing those receiving IABP with those not receiving IABP, there was no difference in favourable functional status at discharge (49.1% vs. 57.1%, p=0.321); and mortality at one year (45.5% vs. 35.5%, p=0.164). Multivariable analyses identified IABP therapy as a strong independent predictor for favourable functional status at discharge (OR=7.51, 95% CI: 2.15-26.14, p=0.002) and this association was maintained in propensity-score adjusted analyses (OR=9.90, 95% CI: 2.11-46.33, p=0.004) and inverse probability treatment weighted analyses (OR=10.84, 95% CI: 2.75-42.69, p<0.001). However, IABP therapy was not an independent predictor for mortality at one year (HR=0.93, 95% CI: 0.52-1.65, p=0.810) and this was confirmed in both propensity-score adjusted and inverse probability treatment weighted analyses. CONCLUSIONS: In this observational analysis of patients surviving an OOHCA, the use of IABP therapy in the post-resuscitation period was associated with improved functional outcomes. This warrants further evaluation in larger prospective studies.

A (14)C-leucine absorption, distribution, metabolism and excretion (ADME) study in adult Sprague-Dawley rat reveals ß-hydroxy-ß-methylbutyrate as a metabolite.

Leucine is an essential branched-chain amino acid that acts as a substrate for protein synthesis and as a signaling molecule. Leucine not incorporated into muscle protein is ultimately oxidized through intermediates such as ß-hydroxy-ß-methylbutyrate (HMB) which itself is reported to enhance muscle mass and function in rats and humans. HMB has been reported in the plasma following oral leucine administration in sheep and pigs but not in Sprague-Dawley rats, the standard preclinical model. Therefore, we conducted radiolabeled absorption, distribution, metabolism and excretion (ADME) studies in rats using a low (3 mg/kg) or high dose (1,000 mg/kg) of (14)C-leucine. Blood, tissue, and urine samples were analyzed for (14)C-leucine and its metabolites by HPLC-MS. Our results show for the first time that (14)C-HMB appears in plasma and urine of rats following an oral dose of (14)C-leucine. (14)C-leucine appears in plasma as (14)C-α-ketoisocaproic acid (KIC) with a slower time course than (14)C-HMB, a putative product of KIC. Further, two novel metabolites of leucine were detected in urine, N-acetyl leucine and glycyl leucine. Mass balance studies demonstrate that excretory routes accounted for no more than 0.9 % of the radiolabel and approximately 61 % of the dose was recovered in the carcass. Approximately 65 % of the dose was recovered in total, suggesting that approximately one-third of the leucine dose is oxidized to CO2. In conclusion, this study demonstrates endogenous production of HMB from leucine in adult rats, a standard preclinical model used to guide design of clinical trials in nutrition.

Henry's law constant and overall mass transfer coefficient for formaldehyde emission from small water pools under simulated indoor environmental conditions.

The Henry's law constant (HLC) and the overall mass transfer coefficient are both important parameters for modeling formaldehyde emissions from aqueous solutions. In this work, the apparent HLCs for formaldehyde aqueous solutions were determined in the concentration range from 0.01% to 1% (w/w) and at different temperatures (23, 40, and 55 °C) by a static headspace extraction method. The aqueous solutions tested included formaldehyde in water, formaldehyde-water with nonionic surfactant Tergitol NP-9, and formaldehyde-water with anionic surfactant sodium dodecyl sulfate. Overall, the measured HLCs ranged from 8.33 × 10(-6) to 1.12 × 10(-4) (gas-concentration/aqueous-concentration, dimensionless). Fourteen small-chamber tests were conducted with formaldehyde solutions in small pools. By applying the measured HLCs, the formaldehyde overall liquid-phase mass transfer coefficients (KOLs) were determined to be in the range of 8.12 × 10(-5) to 2.30 × 10(-4) m/h, and the overall gas-phase mass transfer coefficients were between 2.84 and 13.4 m/h. The influences of the formaldehyde concentration, temperature, agitation rate, and surfactant on HLC and KOL were investigated. This study provides useful data to support source modeling for indoor formaldehyde originating from the use of household products that contain formaldehyde-releasing biocides.

High incidence of acute coronary occlusion in patients without protocol positive ST segment elevation referred to an open access primary angioplasty programme.

BACKGROUND: Primary percutaneous coronary intervention (PPCI) programmes vary in admission criteria from open referral to acceptance of electrocardiogram (ECG) protocol positive patients only. Rigid criteria may result in some patients with acutely occluded coronary arteries not receiving timely reperfusion therapy. OBJECTIVE: To compare the prevalence of acute coronary occlusion and, in these cases, single time point biomarker estimates of myocardial infarct size between patients presenting with protocol positive ECG changes and those presenting with less diagnostic changes in the primary angioplasty cohort of an open access PPCI programme. METHODS: We retrospectively performed a single centre cross sectional analysis of consecutive patients receiving PPCI between January and August 2008. Cases were categorised according to presenting ECG-group A: protocol positive (ST segment elevation/left bundle branch block/posterior ST elevation myocardial infarction), group B: ST segment depression or T-wave inversion, or group C: minor ECG changes. Clinical characteristics, coronary flow grades and 12 h postprocedure troponin-I levels were reviewed. RESULTS: During the study period there were 513 activations of the PPCI service, of which 390 underwent immediate angiography and 308 underwent PPCI. Of those undergoing PPCI, 221 (72%) were in group A, 41 (13%) in group B and 46 (15%) in group C. Prevalence of coronary occlusion was 75% in group A compared with 73% in group B and 63% in group C. Median 12 h postintervention troponin-I (25th-75th percentile) for those with coronary occlusion was significantly higher in group A patients; 28.9 µg/l (13.2-58.5) versus 18.1 µg/l (6.7-32.4) for group B (p=0.03); and 15.5 µg/l (3.8-22.0) for group C (p<0.001), suggesting greater infarct size in group A. CONCLUSIONS: A number of patients referred to an open access PPCI programme have protocol negative ECGs but myocardial infarction and acute coronary artery occlusion amenable to angioplasty.

Effects of a Continuous Adductor Canal Block After Total Knee Arthroplasty.

This retrospective cohort study analyzed the short-term outcomes of patients undergoing total knee arthroplasty receiving periarticular anesthetic injections (PAIs) with and without continuous adductor canal blocks (CACBs) regarding early postoperative narcotic use, pain scores, and range of motion with otherwise similar postoperative regimens. Two hundred ninety-four patients were included: 120 received PAIs with CACBs, and 174 received PAIs only. Matched analysis was performed for type of anesthesia. There were substantial decreases in early inpatient narcotic use with the addition of CACBs to PAIs with general and spinal anesthesia without an adverse effect on pain, knee range of motion, or length of stay. [Orthopedics. 2023;46(3):185-191.].

Synthesis and calorimetric, spectroscopic, and structural characterization of isocyanide complexes of trialkylaluminum and tri-tert-butylgallium.

Addition of tert-butylisocyanide or 2,6-dimethylphenylisocyanide to a solution of trialkylaluminum or trialkylgallium results in formation of complexes R(3)M·C≡N(t)Bu (M = Al, R = Me (1), Et (2), (i)Bu (3), (t)Bu (4); M = Ga, R = (t)Bu (9)) or R(3)M·C≡N(2,6-Me(2)C(6)H(3)) (M = Al, R = Me (5), Et (6), (i)Bu (7), (t)Bu (8); M = Ga, R = (t)Bu (10)), respectively. Complexes 1, 4, 5, and 8-10 are isolated as solids, whereas the triethylaluminum and triisobutylaluminum adducts 2, 3, 6, and 7 are viscous oils. Complexes 1-10 were characterized by NMR ((1)H, (13)C) and IR spectroscopies, and the molecular structures of 4, 5, and 8-10 were also determined by X-ray crystallography. The frequency of the C≡N stretch of the isocyanide increased by 58-91 cm(-1) upon complexation, consistent with coordination of the isocyanide as a σ donor. Enthalpies of complex formation for 1-10 were determined by isothermal titration calorimetry. Enthalpy data suggest the following order of decreasing Lewis acidity: (t)Bu(3)Al ≫ (i)Bu(3)Al ≥ Me(3)Al ≈ Et(3)Al ≫ (t)Bu(3)Ga. In the absence of oxygen and protic reagents, the reported complexes do not undergo insertion or elimination reactions upon heating their benzene-d(6) solutions to 80 °C.

Brachial artery low-flow-mediated constriction is increased early after coronary intervention and reduces during recovery after acute coronary syndrome: characterization of a recently described index of vascular function.

AIMS: The endothelium plays a role in regulating vascular tone. Acute and dynamic changes in low-flow-mediated constriction (L-FMC) and how it changes with regard to traditional flow-mediated dilatation (FMD) have not been described. We aimed to investigate the changes in brachial artery L-FMC following percutaneous coronary intervention (PCI) and during recovery from non-ST-segment elevation myocardial infarction (NSTEMI). METHODS AND RESULTS: FMD was performed in accordance with a previously described technique in patients before and after PCI and in the recovery phase of NSTEMI, but in addition, L-FMC data were acquired from the last 30 s of cuff inflation. About 135 scans were performed in 96 participants (10 healthy volunteers and 86 patients). Measurement of brachial L-FMC was reproducible over hours. L-FMC was greater among patients with unstable vs. stable coronary atherosclerosis (-1.33 ±1.09% vs. -0.03 ± 1.26%, P < 0.01). Following PCI, FMD reduced (4.43 ± 2.93% vs. 1.66 ± 2.16%, P < 0.01) and L-FMC increased (-0.33 ± 0.76% vs. -1.63 ± 1.15%, P = 0.02). Furthermore, during convalescence from NSTEMI, L-FMC reduced (-1.37 ± 1.19% vs. 0.01 ± 0.82%, P = 0.02) in parallel with improvements in FMD (2.54 ± 2.19% vs. 5.15 ± 3.07%, P < 0.01). CONCLUSION: Brachial L-FMC can be measured reliably. Differences were observed between patients with stable and unstable coronary disease. L-FMC was acutely increased following PCI associated with reduced FMD and, in the recovery from NSTEMI, L-FMC reduced associated with increased FMD. These novel findings characterize acute and subacute variations in brachial L-FMC. The pathophysiological and clinical implications of these observations require further study.

Outcomes of the Supine Anterior-based Muscle-sparing Approach for Primary and Revision Hip Arthroplasty.

INTRODUCTION: Risks and outcomes of total hip arthroplasty (THA) are believed to vary relative to the surgical approach. This study compares the supine anterior-based muscle-sparing (ABMS) approach with its modern-day counterparts. METHODS: A retrospective review was done on 550 patients undergoing primary or revision THA from 2016 to 2018. Surgical modalities included direct anterior (DAA), ABMS, posterolateral, and Müller modified Hardinge approaches. Surgical data were collected, and clinical outcomes were measured by the Hip Disability and Osteoarthritis Outcome Score, Modified Harris Hip Score, UCLA, and VR-12 Mental/Physical scores preoperatively and compared clinical outcomes among approaches. RESULTS: A total of 550 patients were included (447 primaries, 103 revisions). The average age was 64 years (231 men, 319 women). Approaches included 79 DAA (14%), 212 ABMS (39%), 180 modified Müller-Hardinge (33%), and 79 posterolateral (14%). The incidence of lateral femoral cutaneous nerve injury was more common with the DAA (P = 0.008), but no other clinically significant differences were noted among the groups. CONCLUSION: The results of this study showed no clinically notable differences between the supine ABMS and other approaches. The supine ABMS approach is an acceptable approach in modern day THA when used by an experienced surgeon well-versed in the approach.

An Orthopaedic Virtual Clinical Clerkship for Visiting Medical Students: Early Successes and Future Implications.

OBJECTIVE: The visiting orthopaedic clerkship is viewed by both students and program directors as an important part of the orthopaedic surgery residency application process, despite being criticized as costly and inefficient. Restrictions due to the COVID-19 pandemic prevented students from participating in in-person clerkships at institutions other than at their home programs, necessitating a virtual replacement for the in-person orthopaedics clerkship experience. It remains unclear how the virtual clerkships will affect the application process this year, and moving forward. We describe and review our institution's initial experience with a virtual orthopaedic clerkship. We hypothesize that students would view the virtual clerkship as valuable, and that students would see a role for such clerkships going forward. DESIGN: A virtual orthopaedic surgery clerkship was created and students were invited to enroll. Thirty-one 4th-year medical students participated. Each clerkship included 8 two-hour sessions. Each session was moderated by a faculty member, and participants included only medical students. Students presented virtual cases, which provided the basis for the discussion and education. At the conclusion of each clerkship, students were given an anonymous survey assessing various aspects of the clerkship. RESULTS: Twenty-seven students responded to the survey. Overall, 15 students rated the experience as outstanding, 11 excellent, and 1 good. Twenty-two students saw a role for virtual clerkships moving forward, and five students did not see a role moving forward. Student reported strengths of the clerkship included direct faculty interaction, structured curriculum, and student-centered discussions. Lack of hands-on experience was cited as the biggest weakness. CONCLUSIONS: Students valued the opportunity for a virtual clerkship, and most could envision a role for such virtual clerkships moving forward. We suggest that virtual clerkships may be a cost-effective and useful tool in helping both students and programs navigate the residency selection process.