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Research on the spherical torus (or spherical tokamak) (ST) is being pursued to explore the scientific benefits of modifying the field line structue fro that in more moderate aspect ratio devices. The ST experiments are being conducted in various US research facilities. The area of power and particle handling is expected to be challenging because of the higher power density expected in the ST relative to that in conventional aspect-ratio tokamaks.

A major research goal of the national spherical torus experiment is establishing long-pulse, high beta, high confinement operation and its physics basis. This research has been enabled by facility capabilities developed during 2001 and 2002, including neutral beam (up to 7 MW) and high harmonic fast wave (HHFW) heating (up to 6 MW), toroidal fields up to 6 kG, plasma currents up to 1.5 MA, flexible shape control, and wall preparation techniques. These capabilities have enabled the generation of plasmas with βT ≡ /(BT02/2μ0) of up to 35%. Normalized beta values often exceed the no-wall limit, and studies suggest that passive wall mode stabilization enables this for H mode plasmas with broad pressure profiles. The viability of long, high bootstrap current fraction operations has been established for ELMing H mode plasmas with toroidal beta values in excess of 15% and sustained for several current relaxation times. Improvements in wall conditioning and fuelling are likely contributing to a reduction in H mode power thresholds. Electron thermal conduction is the dominant thermal loss channel is auxiliary heated plasmas examined thus far. HHFW effectively heats electrons, and its acceleration of fast beam ions has been observed. Evidence for HHFW current drive is obtained by comparison of the loop voltage evolution in plasmas with matched density and temperature profiles but varying phases of launched HHFW waves. Studies of emissions from electron Bernstein waves indicate a density scale length dependence of their transmission across the upper hybrid resonance near the plasma edge that is consistent with theoretical predictions. A peak heat flux to the divertor targets of 10 MW m-2 has been measured in the H mode, with large asymmetries being observed in the power deposition between the inner and outer strike points. Non-inductive plasma startup studies have focused on coaxial helicity injection. With this technique, toroidal currents up to 400 kA have been driven, and studies to assess flux closure and coupling to other current drive techniques have begun.

Objective: To compare the incidence in postsurgical persistent pain following breast cancer surgery in women receiving intravenous lidocaine compared to saline using validated pain instruments in accordance with the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) recommendations., Methods: The study was a randomized, double-blinded, placebo-controlled, clinical trial. Subjects were randomized into Group 1 (1.5 mg/kg bolus of intravenous lidocaine followed by a 2 mg/kg/hour infusion) or Group 2 (normal saline at the same bolus and infusion rate). Patients were evaluated at 3 and 6 months for the presence of chronic persistent postsurgical pain., Results: One hundred forty-eight patients were included in the study analysis. There were no differences in quality of recovery, pain burden, or opioid consumption between groups at 24 hours. Pain (yes/no) at 6 months attributed to surgery was reported in 29% of Group 2 vs. 13% of Group 1 patients (P = 0.04); however, only 3 subjects (5%) in Group 1 and 2 subjects (3%) in Group 2 met IMMPACT criteria for persistent postoperative pain (P = 0.99)., Discussion: Perioperative infusion of lidocaine has been reported to decrease the incidence of postsurgical pain at 3 and 6 months following mastectomy using dichotomous (yes/no) scoring. Although intravenous lidocaine reduced the reported incidence of pain at rest at 6 months, pain with activity, pain qualities, and the physical or emotional impact of the pain were unaffected. Future studies evaluating postsurgical persistent pain should adhere to the IMMPACT recommendations in order to more accurately describe the effect of an intervention on persistent pain., (© 2017 World Institute of Pain.)

Background and Objectives: Perioperative modulation of the surgical inflammatory response has been hypothesized as a viable pharmacological preventive target for the development of chronic pain after surgery. The objective of the current investigation was to evaluate an association between intravenous dexamethasone 4 to 20 mg on the day of surgery with self-reported pain in the breast or axilla 3 months or more after mastectomy., Methods: The study was a secondary data analysis of a prospective cohort investigation. Subjects who have undergone mastectomy surgery were evaluated at least 3 months after the surgical procedure for the presence of chronic postsurgical pain using validated pain questionnaires. Binary logistic regression analysis was used to determine the odds of development of chronic postsurgical pain in subjects who did and did not receive perioperative dexamethasone., Results: Three hundred ten patients were included in the study. Fifty-two patients (17%) met the IMMPACT (Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials) criteria for chronic pain in the breast and/or axillary region. Two hundred eleven (68%) of 310 subjects received perioperative dexamethasone on doses varying from 4 to 20 mg. The incidence of chronic pain in the mastectomy group who received perioperative dexamethasone was not different, 15 (15.2%) of 84 compared with 37 (17.5%) of 211 in the group who did not receive perioperative dexamethasone, difference -2% (95% confidence interval, -10 to 7; P = 0.75)., Conclusions: Perioperative dexamethasone is not associated with a reduction in the incidence and/or severity of chronic postmastectomy pain. In addition, we did not detect a dose-response effect of dexamethasone on the incidence of chronic postsurgical pain.

Background: Supervision of anesthesiology residents is a major responsibility of faculty (academic) anesthesiologists. Supervision can be evaluated daily for individual anesthesiologists using a 9-question instrument. Faculty anesthesiologists with lesser individual scores contribute to lesser departmental (global) scores. Low (<3, "frequent") department-wide evaluations of supervision are associated with more mistakes with negative consequences to patients. With the long-term aim for residency programs to be evaluated partly based on the quality of their resident supervision, we assessed the 9-item instrument's reliability and validity when used to compare anesthesia programs' rotations nationwide., Methods: One thousand five hundred residents in the American Society of Anesthesiologists' directory of anesthesia trainees were randomly selected to be participants. Residents were contacted via e-mail and requested to complete a Web-based survey. Nonrespondents were mailed a paper version of the survey., Results: Internal consistency of the supervision scale was excellent, with Cronbach's α = 0.909 (95% CI, 0.896-0.922, n = 641 respondents). Discriminant validity was found based on absence of rank correlation of supervision score with characteristics of the respondents and programs (all P > 0.10): age, hours worked per week, female, year of anesthesia training, weeks in the current rotation, sequence of survey response, size of residency class, and number of survey respondents from the current rotation and program. Convergent validity was found based on significant positive correlation between supervision score and variables related to safety culture (all P < 0.0001): "Overall perceptions of patient safety," "Teamwork within units," "Nonpunitive response to errors," "Handoffs and transitions," "Feedback and communication about error," "Communication openness," and rotation's "overall grade on patient safety." Convergent validity was found also based on significant negative correlation with variables related to the individual resident's burnout (all P < 0.0001): "I feel burnout from my work," "I have become more callous toward people since I took this job," and numbers of "errors with potential negative consequences to patients [that you have] made and/or witnessed." Usefulness was shown by supervision being predicted by the same 1 variable for each of 3 regression tree criteria: "Teamwork within [the rotation]" (e.g., "When one area in this rotation gets busy, others help out")., Conclusions: Evaluation of the overall quality of supervision of residents by faculty anesthesiologists depends on the reliability and validity of the instrument. Our results show that the 9-item de Oliveira Filho et al. supervision scale can be applied for overall (department, rotation) assessment of anesthesia training programs.

Objectives: To compare if mastectomy with reconstructive surgery had greater incidence of chronic pain compared to mastectomy surgery alone., Materials and Methods: The study was a retrospective cohort. Patients who underwent mastectomies with and without reconstruction responded to the modified short form Brief Pain Inventory and the short form McGill pain questionnaire to identify and characterize pain at least 6 months after the surgical procedure. Propensity matching analysis was used to control for covariates differences in the study groups., Results: 310 subjects were included and 132 patients (43%) reported the presence of chronic pain. After propensity score matching to adjust for covariate imbalances, the incidence of chronic pain in the mastectomy group who had additional surgery for breast reconstruction was not different compared to the group who had mastectomy surgery alone, 26 out of 68 (38%) and 27 out of 68 (39%), respectively P = 1.0. Among patients who had chronic pain, breast reconstruction did not increase the intensity of worst pain in the last 24 h, median (IQR) of 2 (1-5) compared to 4 (1-5) in the no reconstruction group, P = 0.41. Type of reconstruction (breast implants vs. flap tissue) did not result in greater incidence and/or intensity of chronic pain., Conclusions: Breast reconstruction after mastectomy does not result in a greater incidence of chronic pain compared to mastectomy alone. Female patients undergoing breast cancer surgery should not incorporate chronic pain in their decision to undergo reconstructive surgery after mastectomy., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Objective: To evaluate the relationship of preoperative thermal quantitative sensory testing (QST) values with postoperative pain and opiate consumption in opiate-naïve patients following gynecologic surgery., Design: Single blind observational study., Settings: Surgical center of an academic medical center., Methods: QST was performed preoperatively on 124 opioid-naïve patients. Pain outcomes were assessed on arrival to the post-anesthesia care unit and at 6 hourly intervals for 24 hours. Subjects were reclassified to three groups: Group 1 had a heat pain threshold above and a cold pain threshold below the median; Group 2 had either a heat pain threshold below or a cold pain threshold above the median; Group 3 had a heat pain threshold below and a cold pain threshold above the median. The primary outcome measure was the 24-hour morphine consumption., Results: One hundred twenty subjects were evaluated. Median (interquartile range) warm and cold pain thresholds were 44.8 (42.4-46.9) °C and 10.5 (3.2-19.0) °C, respectively. Heat pain thresholds demonstrated a negative (rho = -0.23, P = 0.01) and cold thresholds a positive correlation (rho = 0.21, P = 0.02) with 24-hour morphine consumption. Median morphine consumption was 19 (2-33) mg (P = 0.004) equivalents greater in subjects (N = 46) with heat pain thresholds <45 °C and cold pain thresholds >10 °C than subjects with heat pain thresholds >45 °C and cold pain thresholds <10 °C., Discussion: Reduced tolerance to both heat and cold thermal pain stimulus was associated with increased postoperative analgesic requirements. Combined responses to multiple pain modalities may be more useful than a single stimulus paradigm., (Wiley Periodicals, Inc.)

The resistive-wall mode is actively stabilized in the National Spherical Torus Experiment in high-beta plasmas rotating significantly below the critical rotation speed for passive stability and in the range predicted for the International Thermonuclear Experimental Reactor. Variation of feedback stabilization parameters shows mode excitation or suppression. Stabilization of toroidal mode number unity did not lead to instability of toroidal mode number two. The mode can become unstable by deforming poloidally, an important consideration for stabilization system design.

Dissipation of plasma toroidal angular momentum is observed in the National Spherical Torus Experiment due to applied nonaxisymmetric magnetic fields and their plasma-induced increase by resonant field amplification and resistive wall mode destabilization. The measured decrease of the plasma toroidal angular momentum profile is compared to calculations of nonresonant drag torque based on the theory of neoclassical toroidal viscosity. Quantitative agreement between experiment and theory is found when the effect of toroidally trapped particles is included.