Suppression of charged particle production at large transverse momentum in central Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV

Inclusive transverse momentum spectra of primary charged particles in Pb-Pb collisions at $\sqrt{s_{_{\rm NN}}}$ = 2.76 TeV have been measured by the ALICE Collaboration at the LHC. The data are presented for central and peripheral collisions, corresponding to 0-5% and 70-80% of the hadronic Pb-Pb cross section. The measured charged particle spectra in $|\eta|<0.8$ and $0.3 < p_T < 20$ GeV/$c$ are compared to the expectation in pp collisions at the same $\sqrt{s_{\rm NN}}$, scaled by the number of underlying nucleon-nucleon collisions. The comparison is expressed in terms of the nuclear modification factor $R_{\rm AA}$. The result indicates only weak medium effects ($R_{\rm AA} \approx$ 0.7) in peripheral collisions. In central collisions, $R_{\rm AA}$ reaches a minimum of about 0.14 at $p_{\rm T}=6$-7GeV/$c$ and increases significantly at larger $p_{\rm T}$. The measured suppression of high-$p_{\rm T}$ particles is stronger than that observed at lower collision energies, indicating that a very dense medium is formed in central Pb-Pb collisions at the LHC.Comment: 15 pages, 5 captioned figures, 3 tables, authors from page 10, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/98

Two-pion Bose-Einstein correlations in central Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV

The first measurement of two-pion Bose-Einstein correlations in central Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV at the Large Hadron Collider is presented. We observe a growing trend with energy now not only for the longitudinal and the outward but also for the sideward pion source radius. The pion homogeneity volume and the decoupling time are significantly larger than those measured at RHIC.Comment: 17 pages, 5 captioned figures, 1 table, authors from page 12, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/388

Transversus abdominis plane block with liposomal bupivacaine for pain control after cesarean delivery: a retrospective chart review

B Wycke Baker,1&ndash;4 Lea G Villadiego,1,2 Y Natasha Lake,1,2 Yazan Amin,3 Audra E Timmins,3 Laurie S Swaim,3 David W Ashton3 1Department of Obstetrical and Gynecological Anesthesiology, Texas Children&rsquo;s Hospital Pavilion for Women, Houston, TX, USA; 2US Anesthesia Partners, Houston, TX, USA; 3Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX, USA; 4Department of Anesthesiology, Baylor College of Medicine, Houston, TX, USA Background: Adverse effects of opioid analgesics and potential for chronic use are limitations in the cesarean setting. Regional anesthesia using transversus abdominis plane (TAP) block post-cesarean delivery may improve analgesia and reduce opioid consumption. Effectiveness of TAP block using liposomal bupivacaine (LB) to reduce post-cesarean pain is unknown.Methods: We performed a single-center retrospective chart review of patients aged &ge;18 years who underwent cesarean delivery with a multimodal pain management protocol with or without TAP block with LB 266 mg. Assessments included postsurgical opioid consumption; area under the curve (AUC) of numeric rating scale pain scores from 0 to 3 days; proportion of opioid-free patients; discharge- and post-anesthesia care unit (PACU)-ready time; times to ambulation, solid food, and bowel movement; hospital length of stay (LOS); and adverse events (AEs). Data were analyzed in the total population and in first- and repeat-cesarean subgroups using Wilcoxon, chi-squared, and Student&rsquo;s t-tests.Results: Of 201 patients, 101 were treated with LB TAP block (LB-TAPB) and 100 without LB-TAPB. Treatment with LB-TAPB vs without LB-TAPB significantly reduced mean postsurgical opioid consumption (total, 47%; first-cesarean, 54%; repeat-cesarean, 42%; P&lt;0.001 each) and mean AUC of pain scores (total, 46%; first-cesarean, 57%; repeat-cesarean, 40%; P&lt;0.001 each). Patients treated with LB-TAPB had significantly shorter mean discharge-ready times (2.9 vs 3.6 days; P=0.006), PACU-ready times (138 vs 163 minutes; P=0.028), and LOS (2.9 vs 3.9 days; P&lt;0.001). LB-TAPB significantly decreased mean times to ambulation and solid food by 39% and 31% (P&lt;0.01 each), respectively, and numerically reduced mean time to bowel movement (26%; P=0.05). Fewer patients treated with LB-TAPB vs without LB-TAPB reported an AE (34% vs 50%; P=0.026).Conclusion: These results suggest multimodal pain management incorporating TAP block with LB 266 mg is an effective approach to reducing opioid requirements and improving analgesia post-cesarean delivery. Keywords: transversus abdominis plane block, liposomal bupivacaine, cesarean section, postoperative pain managemen