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Aguillard DP, Albahri T, Allspach D, Anisenkov A, Badgley K, Baeßler S, Bailey I, Bailey L, Baranov VA, Barlas-Yucel E, Barrett T, Barzi E, Bedeschi F, Berz M, Bhattacharya M, Binney HP, Bloom P, Bono J, Bottalico E, Bowcock T, Braun S, Bressler M, Cantatore G, Carey RM, Casey BCK, Cauz D, Chakraborty R, Chapelain A, Chappa S, Charity S, Chen C, Cheng M, Chislett R, Chu Z, Chupp TE, Claessens C, Convery ME, Corrodi S, Cotrozzi L, Crnkovic JD, Dabagov S, Debevec PT, Di Falco S, Di Sciascio G, Drendel B, Driutti A, Duginov VN, Eads M, Edmonds A, Esquivel J, Farooq M, Fatemi R, Ferrari C, Fertl M, Fienberg AT, Fioretti A, Flay D, Foster SB, Friedsam H, Froemming NS, Gabbanini C, Gaines I, Galati MD, Ganguly S, Garcia A, George J, Gibbons LK, Gioiosa A, Giovanetti KL, Girotti P, Gohn W, Goodenough L, Gorringe T, Grange J, Grant S, Gray F, Haciomeroglu S, Halewood-Leagas T, Hampai D, Han F, Hempstead J, Hertzog DW, Hesketh G, Hess E, Hibbert A, Hodge Z, Hong KW, Hong R, Hu T, Hu Y, Iacovacci M, Incagli M, Kammel P, Kargiantoulakis M, Karuza M, Kaspar J, Kawall D, Kelton L, Keshavarzi A, Kessler DS, Khaw KS, Khechadoorian Z, Khomutov NV, Kiburg B, Kiburg M, Kim O, Kinnaird N, Kraegeloh E, Krylov VA, Kuchinskiy NA, Labe KR, LaBounty J, Lancaster M, Lee S, Li B, Li D, Li L, Logashenko I, Lorente Campos A, Lu Z, Lucà A, Lukicov G, Lusiani A, Lyon AL, MacCoy B, Madrak R, Makino K, Mastroianni S, Miller JP, Miozzi S, Mitra B, Morgan JP, Morse WM, Mott J, Nath A, Ng JK, Nguyen H, Oksuzian Y, Omarov Z, Osofsky R, Park S, Pauletta G, Piacentino GM, Pilato RN, Pitts KT, Plaster B, Počanić D, Pohlman N, Polly CC, Price J, Quinn B, Qureshi MUH, Ramachandran S, Ramberg E, Reimann R, Roberts BL, Rubin DL, Santi L, Schlesier C, Schreckenberger A, Semertzidis YK, Shemyakin D, Sorbara M, Stöckinger D, Stapleton J, Still D, Stoughton C, Stratakis D, Swanson HE, Sweetmore G, Sweigart DA, Syphers MJ, Tarazona DA, Teubner T, Tewsley-Booth AE, Tishchenko V, Tran NH, Turner W, Valetov E, Vasilkova D, Venanzoni G, Volnykh VP, Walton T, Weisskopf A, Welty-Rieger L, Winter P, Wu Y, Yu B, Yucel M, Zeng Y, Zhang C. Measurement of the Positive Muon Anomalous Magnetic Moment to 0.20 ppm. Phys Rev Lett 2023; 131:161802. [PMID: 37925710 DOI: 10.1103/physrevlett.131.161802] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 09/05/2023] [Indexed: 11/07/2023]
Abstract
We present a new measurement of the positive muon magnetic anomaly, a_{μ}≡(g_{μ}-2)/2, from the Fermilab Muon g-2 Experiment using data collected in 2019 and 2020. We have analyzed more than 4 times the number of positrons from muon decay than in our previous result from 2018 data. The systematic error is reduced by more than a factor of 2 due to better running conditions, a more stable beam, and improved knowledge of the magnetic field weighted by the muon distribution, ω[over ˜]_{p}^{'}, and of the anomalous precession frequency corrected for beam dynamics effects, ω_{a}. From the ratio ω_{a}/ω[over ˜]_{p}^{'}, together with precisely determined external parameters, we determine a_{μ}=116 592 057(25)×10^{-11} (0.21 ppm). Combining this result with our previous result from the 2018 data, we obtain a_{μ}(FNAL)=116 592 055(24)×10^{-11} (0.20 ppm). The new experimental world average is a_{μ}(exp)=116 592 059(22)×10^{-11} (0.19 ppm), which represents a factor of 2 improvement in precision.
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Affiliation(s)
| | - T Albahri
- University of Liverpool, Liverpool, United Kingdom
| | - D Allspach
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - A Anisenkov
- Budker Institute of Nuclear Physics, Novosibirsk, Russia
| | - K Badgley
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - S Baeßler
- University of Virginia, Charlottesville, Virginia, USA
| | - I Bailey
- Lancaster University, Lancaster, United Kingdom
| | - L Bailey
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - V A Baranov
- Joint Institute for Nuclear Research, Dubna, Russia
| | - E Barlas-Yucel
- University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - T Barrett
- Cornell University, Ithaca, New York, USA
| | - E Barzi
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | | | - M Berz
- Michigan State University, East Lansing, Michigan, USA
| | - M Bhattacharya
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - H P Binney
- University of Washington, Seattle, Washington, USA
| | - P Bloom
- North Central College, Naperville, Illinois, USA
| | - J Bono
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - E Bottalico
- University of Liverpool, Liverpool, United Kingdom
| | - T Bowcock
- University of Liverpool, Liverpool, United Kingdom
| | - S Braun
- University of Washington, Seattle, Washington, USA
| | - M Bressler
- Department of Physics, University of Massachusetts, Amherst, Massachusetts, USA
| | | | - R M Carey
- Boston University, Boston, Massachusetts, USA
| | - B C K Casey
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - D Cauz
- Università di Udine, Udine, Italy
| | | | | | - S Chappa
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - S Charity
- University of Liverpool, Liverpool, United Kingdom
| | - C Chen
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, China
| | - M Cheng
- University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - R Chislett
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - Z Chu
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
| | - T E Chupp
- University of Michigan, Ann Arbor, Michigan, USA
| | - C Claessens
- University of Washington, Seattle, Washington, USA
| | - M E Convery
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - S Corrodi
- Argonne National Laboratory, Lemont, Illinois, USA
| | | | - J D Crnkovic
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - S Dabagov
- INFN, Laboratori Nazionali di Frascati, Frascati, Italy
| | - P T Debevec
- University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | | | | | - B Drendel
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | | | - V N Duginov
- Joint Institute for Nuclear Research, Dubna, Russia
| | - M Eads
- Northern Illinois University, DeKalb, Illinois, USA
| | - A Edmonds
- Boston University, Boston, Massachusetts, USA
| | - J Esquivel
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - M Farooq
- University of Michigan, Ann Arbor, Michigan, USA
| | - R Fatemi
- University of Kentucky, Lexington, Kentucky, USA
| | | | - M Fertl
- Institute of Physics and Cluster of Excellence PRISMA+, Johannes Gutenberg University Mainz, Mainz, Germany
| | - A T Fienberg
- University of Washington, Seattle, Washington, USA
| | | | - D Flay
- Department of Physics, University of Massachusetts, Amherst, Massachusetts, USA
| | - S B Foster
- Boston University, Boston, Massachusetts, USA
| | - H Friedsam
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | | | | | - I Gaines
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | | | - S Ganguly
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - A Garcia
- University of Washington, Seattle, Washington, USA
| | - J George
- Department of Physics, University of Massachusetts, Amherst, Massachusetts, USA
| | | | - A Gioiosa
- Università del Molise, Campobasso, Italy
| | - K L Giovanetti
- Department of Physics and Astronomy, James Madison University, Harrisonburg, Virginia, USA
| | | | - W Gohn
- University of Kentucky, Lexington, Kentucky, USA
| | - L Goodenough
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - T Gorringe
- University of Kentucky, Lexington, Kentucky, USA
| | - J Grange
- University of Michigan, Ann Arbor, Michigan, USA
| | - S Grant
- Argonne National Laboratory, Lemont, Illinois, USA
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - F Gray
- Regis University, Denver, Colorado, USA
| | - S Haciomeroglu
- Center for Axion and Precision Physics (CAPP)/Institute for Basic Science (IBS), Daejeon, Republic of Korea
| | | | - D Hampai
- INFN, Laboratori Nazionali di Frascati, Frascati, Italy
| | - F Han
- University of Kentucky, Lexington, Kentucky, USA
| | - J Hempstead
- University of Washington, Seattle, Washington, USA
| | - D W Hertzog
- University of Washington, Seattle, Washington, USA
| | - G Hesketh
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - E Hess
- INFN, Sezione di Pisa, Pisa, Italy
| | - A Hibbert
- University of Liverpool, Liverpool, United Kingdom
| | - Z Hodge
- University of Washington, Seattle, Washington, USA
| | - K W Hong
- University of Virginia, Charlottesville, Virginia, USA
| | - R Hong
- Argonne National Laboratory, Lemont, Illinois, USA
- University of Kentucky, Lexington, Kentucky, USA
| | - T Hu
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, China
| | - Y Hu
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
| | | | | | - P Kammel
- University of Washington, Seattle, Washington, USA
| | | | - M Karuza
- INFN, Sezione di Trieste, Trieste, Italy
| | - J Kaspar
- University of Washington, Seattle, Washington, USA
| | - D Kawall
- Department of Physics, University of Massachusetts, Amherst, Massachusetts, USA
| | - L Kelton
- University of Kentucky, Lexington, Kentucky, USA
| | - A Keshavarzi
- Department of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | - D S Kessler
- Department of Physics, University of Massachusetts, Amherst, Massachusetts, USA
| | - K S Khaw
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, China
| | | | - N V Khomutov
- Joint Institute for Nuclear Research, Dubna, Russia
| | - B Kiburg
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - M Kiburg
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
- North Central College, Naperville, Illinois, USA
| | - O Kim
- University of Mississippi, University, Mississippi, USA
| | - N Kinnaird
- Boston University, Boston, Massachusetts, USA
| | - E Kraegeloh
- University of Michigan, Ann Arbor, Michigan, USA
| | - V A Krylov
- Joint Institute for Nuclear Research, Dubna, Russia
| | | | - K R Labe
- Cornell University, Ithaca, New York, USA
| | - J LaBounty
- University of Washington, Seattle, Washington, USA
| | - M Lancaster
- Department of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | - S Lee
- Center for Axion and Precision Physics (CAPP)/Institute for Basic Science (IBS), Daejeon, Republic of Korea
| | - B Li
- Argonne National Laboratory, Lemont, Illinois, USA
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
| | - D Li
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
| | - L Li
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
| | - I Logashenko
- Budker Institute of Nuclear Physics, Novosibirsk, Russia
| | | | - Z Lu
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
| | - A Lucà
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - G Lukicov
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | | | - A L Lyon
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - B MacCoy
- University of Washington, Seattle, Washington, USA
| | - R Madrak
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - K Makino
- Michigan State University, East Lansing, Michigan, USA
| | | | - J P Miller
- Boston University, Boston, Massachusetts, USA
| | - S Miozzi
- INFN, Sezione di Roma Tor Vergata, Rome, Italy
| | - B Mitra
- University of Mississippi, University, Mississippi, USA
| | - J P Morgan
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - W M Morse
- Brookhaven National Laboratory, Upton, New York, USA
| | - J Mott
- Boston University, Boston, Massachusetts, USA
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - A Nath
- INFN, Sezione di Napoli, Naples, Italy
| | - J K Ng
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, China
| | - H Nguyen
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - Y Oksuzian
- Argonne National Laboratory, Lemont, Illinois, USA
| | - Z Omarov
- Center for Axion and Precision Physics (CAPP)/Institute for Basic Science (IBS), Daejeon, Republic of Korea
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - R Osofsky
- University of Washington, Seattle, Washington, USA
| | - S Park
- Center for Axion and Precision Physics (CAPP)/Institute for Basic Science (IBS), Daejeon, Republic of Korea
| | | | | | - R N Pilato
- University of Liverpool, Liverpool, United Kingdom
| | - K T Pitts
- University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - B Plaster
- University of Kentucky, Lexington, Kentucky, USA
| | - D Počanić
- University of Virginia, Charlottesville, Virginia, USA
| | - N Pohlman
- Northern Illinois University, DeKalb, Illinois, USA
| | - C C Polly
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - J Price
- University of Liverpool, Liverpool, United Kingdom
| | - B Quinn
- University of Mississippi, University, Mississippi, USA
| | - M U H Qureshi
- Institute of Physics and Cluster of Excellence PRISMA+, Johannes Gutenberg University Mainz, Mainz, Germany
| | | | - E Ramberg
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - R Reimann
- Institute of Physics and Cluster of Excellence PRISMA+, Johannes Gutenberg University Mainz, Mainz, Germany
| | - B L Roberts
- Boston University, Boston, Massachusetts, USA
| | - D L Rubin
- Cornell University, Ithaca, New York, USA
| | - L Santi
- Università di Udine, Udine, Italy
| | - C Schlesier
- University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | | | - Y K Semertzidis
- Center for Axion and Precision Physics (CAPP)/Institute for Basic Science (IBS), Daejeon, Republic of Korea
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - D Shemyakin
- Budker Institute of Nuclear Physics, Novosibirsk, Russia
| | - M Sorbara
- INFN, Sezione di Roma Tor Vergata, Rome, Italy
| | - D Stöckinger
- Institut für Kern- und Teilchenphysik, Technische Universität Dresden, Dresden, Germany
| | - J Stapleton
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - D Still
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - C Stoughton
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - D Stratakis
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - H E Swanson
- University of Washington, Seattle, Washington, USA
| | - G Sweetmore
- Department of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | | | - M J Syphers
- Northern Illinois University, DeKalb, Illinois, USA
| | - D A Tarazona
- Cornell University, Ithaca, New York, USA
- Michigan State University, East Lansing, Michigan, USA
- University of Liverpool, Liverpool, United Kingdom
| | - T Teubner
- University of Liverpool, Liverpool, United Kingdom
| | - A E Tewsley-Booth
- University of Kentucky, Lexington, Kentucky, USA
- University of Michigan, Ann Arbor, Michigan, USA
| | - V Tishchenko
- Brookhaven National Laboratory, Upton, New York, USA
| | - N H Tran
- Boston University, Boston, Massachusetts, USA
| | - W Turner
- University of Liverpool, Liverpool, United Kingdom
| | - E Valetov
- Michigan State University, East Lansing, Michigan, USA
| | - D Vasilkova
- Department of Physics and Astronomy, University College London, London, United Kingdom
- University of Liverpool, Liverpool, United Kingdom
| | - G Venanzoni
- University of Liverpool, Liverpool, United Kingdom
| | - V P Volnykh
- Joint Institute for Nuclear Research, Dubna, Russia
| | - T Walton
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - A Weisskopf
- Michigan State University, East Lansing, Michigan, USA
| | - L Welty-Rieger
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - P Winter
- Argonne National Laboratory, Lemont, Illinois, USA
| | - Y Wu
- Argonne National Laboratory, Lemont, Illinois, USA
| | - B Yu
- University of Mississippi, University, Mississippi, USA
| | - M Yucel
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - Y Zeng
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, China
| | - C Zhang
- University of Liverpool, Liverpool, United Kingdom
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Byron W, Harrington H, Taylor RJ, DeGraw W, Buzinsky N, Dodson B, Fertl M, García A, Garvey G, Graner B, Guigue M, Hayen L, Huyan X, Khaw KS, Knutsen K, McClain D, Melconian D, Müller P, Novitski E, Oblath NS, Robertson RGH, Rybka G, Savard G, Smith E, Stancil DD, Sternberg M, Storm DW, Swanson HE, Tedeschi JR, VanDevender BA, Wietfeldt FE, Young AR, Zhu X. First Observation of Cyclotron Radiation from MeV-Scale e^{±} following Nuclear β Decay. Phys Rev Lett 2023; 131:082502. [PMID: 37683153 DOI: 10.1103/physrevlett.131.082502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 05/03/2023] [Accepted: 07/12/2023] [Indexed: 09/10/2023]
Abstract
We present an apparatus for detection of cyclotron radiation yielding a frequency-based β^{±} kinetic energy determination in the 5 keV to 2.1 MeV range, characteristic of nuclear β decays. The cyclotron frequency of the radiating β particles in a magnetic field is used to determine the β energy precisely. Our work establishes the foundation to apply the cyclotron radiation emission spectroscopy (CRES) technique, developed by the Project 8 Collaboration, far beyond the 18-keV tritium endpoint region. We report initial measurements of β^{-}'s from ^{6}He and β^{+}'s from ^{19}Ne decays to demonstrate the broadband response of our detection system and assess potential systematic uncertainties for β spectroscopy over the full (MeV) energy range. To our knowledge, this is the first direct observation of cyclotron radiation from individual highly relativistic β's in a waveguide. This work establishes the application of CRES to a variety of nuclei, opening its reach to searches for new physics beyond the TeV scale via precision β-decay measurements.
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Affiliation(s)
- W Byron
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
- Center for Nuclear Physics and Astrophysics, University of Washington, Seattle, Washington 98195, USA
| | - H Harrington
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
- Center for Nuclear Physics and Astrophysics, University of Washington, Seattle, Washington 98195, USA
| | - R J Taylor
- Physics Department, North Carolina State University, Raleigh, North Carolina 27695, USA
- The Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA
| | - W DeGraw
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
- Center for Nuclear Physics and Astrophysics, University of Washington, Seattle, Washington 98195, USA
| | - N Buzinsky
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
- Center for Nuclear Physics and Astrophysics, University of Washington, Seattle, Washington 98195, USA
| | - B Dodson
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
- Center for Nuclear Physics and Astrophysics, University of Washington, Seattle, Washington 98195, USA
| | - M Fertl
- Institute for Physics, Johannes-Gutenberg University Mainz, 55128 Mainz, Germany
| | - A García
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
- Center for Nuclear Physics and Astrophysics, University of Washington, Seattle, Washington 98195, USA
| | - G Garvey
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
- Center for Nuclear Physics and Astrophysics, University of Washington, Seattle, Washington 98195, USA
| | - B Graner
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
- Center for Nuclear Physics and Astrophysics, University of Washington, Seattle, Washington 98195, USA
| | - M Guigue
- Pacific Northwest National Laboratory, Richland, Washington 99352, USA
| | - L Hayen
- Physics Department, North Carolina State University, Raleigh, North Carolina 27695, USA
- The Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA
| | - X Huyan
- Pacific Northwest National Laboratory, Richland, Washington 99352, USA
| | - K S Khaw
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
- Center for Nuclear Physics and Astrophysics, University of Washington, Seattle, Washington 98195, USA
| | - K Knutsen
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
- Center for Nuclear Physics and Astrophysics, University of Washington, Seattle, Washington 98195, USA
| | - D McClain
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
- Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA
| | - D Melconian
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
- Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA
| | - P Müller
- Physics Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA
| | - E Novitski
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
- Center for Nuclear Physics and Astrophysics, University of Washington, Seattle, Washington 98195, USA
| | - N S Oblath
- Pacific Northwest National Laboratory, Richland, Washington 99352, USA
| | - R G H Robertson
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
- Center for Nuclear Physics and Astrophysics, University of Washington, Seattle, Washington 98195, USA
| | - G Rybka
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
- Center for Nuclear Physics and Astrophysics, University of Washington, Seattle, Washington 98195, USA
| | - G Savard
- Physics Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA
| | - E Smith
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
- Center for Nuclear Physics and Astrophysics, University of Washington, Seattle, Washington 98195, USA
| | - D D Stancil
- Department of Electrical and Computer Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - M Sternberg
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
- Center for Nuclear Physics and Astrophysics, University of Washington, Seattle, Washington 98195, USA
| | - D W Storm
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
- Center for Nuclear Physics and Astrophysics, University of Washington, Seattle, Washington 98195, USA
| | - H E Swanson
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
- Center for Nuclear Physics and Astrophysics, University of Washington, Seattle, Washington 98195, USA
| | - J R Tedeschi
- Pacific Northwest National Laboratory, Richland, Washington 99352, USA
| | - B A VanDevender
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
- Pacific Northwest National Laboratory, Richland, Washington 99352, USA
| | - F E Wietfeldt
- Department of Physics and Engineering Physics, Tulane University, New Orleans, Louisiana 70118, USA
| | - A R Young
- Physics Department, North Carolina State University, Raleigh, North Carolina 27695, USA
- The Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA
| | - X Zhu
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
- Center for Nuclear Physics and Astrophysics, University of Washington, Seattle, Washington 98195, USA
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Abi B, Albahri T, Al-Kilani S, Allspach D, Alonzi LP, Anastasi A, Anisenkov A, Azfar F, Badgley K, Baeßler S, Bailey I, Baranov VA, Barlas-Yucel E, Barrett T, Barzi E, Basti A, Bedeschi F, Behnke A, Berz M, Bhattacharya M, Binney HP, Bjorkquist R, Bloom P, Bono J, Bottalico E, Bowcock T, Boyden D, Cantatore G, Carey RM, Carroll J, Casey BCK, Cauz D, Ceravolo S, Chakraborty R, Chang SP, Chapelain A, Chappa S, Charity S, Chislett R, Choi J, Chu Z, Chupp TE, Convery ME, Conway A, Corradi G, Corrodi S, Cotrozzi L, Crnkovic JD, Dabagov S, De Lurgio PM, Debevec PT, Di Falco S, Di Meo P, Di Sciascio G, Di Stefano R, Drendel B, Driutti A, Duginov VN, Eads M, Eggert N, Epps A, Esquivel J, Farooq M, Fatemi R, Ferrari C, Fertl M, Fiedler A, Fienberg AT, Fioretti A, Flay D, Foster SB, Friedsam H, Frlež E, Froemming NS, Fry J, Fu C, Gabbanini C, Galati MD, Ganguly S, Garcia A, Gastler DE, George J, Gibbons LK, Gioiosa A, Giovanetti KL, Girotti P, Gohn W, Gorringe T, Grange J, Grant S, Gray F, Haciomeroglu S, Hahn D, Halewood-Leagas T, Hampai D, Han F, Hazen E, Hempstead J, Henry S, Herrod AT, Hertzog DW, Hesketh G, Hibbert A, Hodge Z, Holzbauer JL, Hong KW, Hong R, Iacovacci M, Incagli M, Johnstone C, Johnstone JA, Kammel P, Kargiantoulakis M, Karuza M, Kaspar J, Kawall D, Kelton L, Keshavarzi A, Kessler D, Khaw KS, Khechadoorian Z, Khomutov NV, Kiburg B, Kiburg M, Kim O, Kim SC, Kim YI, King B, Kinnaird N, Korostelev M, Kourbanis I, Kraegeloh E, Krylov VA, Kuchibhotla A, Kuchinskiy NA, Labe KR, LaBounty J, Lancaster M, Lee MJ, Lee S, Leo S, Li B, Li D, Li L, Logashenko I, Lorente Campos A, Lucà A, Lukicov G, Luo G, Lusiani A, Lyon AL, MacCoy B, Madrak R, Makino K, Marignetti F, Mastroianni S, Maxfield S, McEvoy M, Merritt W, Mikhailichenko AA, Miller JP, Miozzi S, Morgan JP, Morse WM, Mott J, Motuk E, Nath A, Newton D, Nguyen H, Oberling M, Osofsky R, Ostiguy JF, Park S, Pauletta G, Piacentino GM, Pilato RN, Pitts KT, Plaster B, Počanić D, Pohlman N, Polly CC, Popovic M, Price J, Quinn B, Raha N, Ramachandran S, Ramberg E, Rider NT, Ritchie JL, Roberts BL, Rubin DL, Santi L, Sathyan D, Schellman H, Schlesier C, Schreckenberger A, Semertzidis YK, Shatunov YM, Shemyakin D, Shenk M, Sim D, Smith MW, Smith A, Soha AK, Sorbara M, Stöckinger D, Stapleton J, Still D, Stoughton C, Stratakis D, Strohman C, Stuttard T, Swanson HE, Sweetmore G, Sweigart DA, Syphers MJ, Tarazona DA, Teubner T, Tewsley-Booth AE, Thomson K, Tishchenko V, Tran NH, Turner W, Valetov E, Vasilkova D, Venanzoni G, Volnykh VP, Walton T, Warren M, Weisskopf A, Welty-Rieger L, Whitley M, Winter P, Wolski A, Wormald M, Wu W, Yoshikawa C. Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm. Phys Rev Lett 2021; 126:141801. [PMID: 33891447 DOI: 10.1103/physrevlett.126.141801] [Citation(s) in RCA: 111] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Accepted: 03/25/2021] [Indexed: 06/12/2023]
Abstract
We present the first results of the Fermilab National Accelerator Laboratory (FNAL) Muon g-2 Experiment for the positive muon magnetic anomaly a_{μ}≡(g_{μ}-2)/2. The anomaly is determined from the precision measurements of two angular frequencies. Intensity variation of high-energy positrons from muon decays directly encodes the difference frequency ω_{a} between the spin-precession and cyclotron frequencies for polarized muons in a magnetic storage ring. The storage ring magnetic field is measured using nuclear magnetic resonance probes calibrated in terms of the equivalent proton spin precession frequency ω[over ˜]_{p}^{'} in a spherical water sample at 34.7 °C. The ratio ω_{a}/ω[over ˜]_{p}^{'}, together with known fundamental constants, determines a_{μ}(FNAL)=116 592 040(54)×10^{-11} (0.46 ppm). The result is 3.3 standard deviations greater than the standard model prediction and is in excellent agreement with the previous Brookhaven National Laboratory (BNL) E821 measurement. After combination with previous measurements of both μ^{+} and μ^{-}, the new experimental average of a_{μ}(Exp)=116 592 061(41)×10^{-11} (0.35 ppm) increases the tension between experiment and theory to 4.2 standard deviations.
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Affiliation(s)
- B Abi
- University of Oxford, Oxford, United Kingdom
| | - T Albahri
- University of Liverpool, Liverpool, United Kingdom
| | - S Al-Kilani
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - D Allspach
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - L P Alonzi
- University of Washington, Seattle, Washington, USA
| | | | - A Anisenkov
- Budker Institute of Nuclear Physics, Novosibirsk, Russia
| | - F Azfar
- University of Oxford, Oxford, United Kingdom
| | - K Badgley
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - S Baeßler
- University of Virginia, Charlottesville, Virginia, USA
| | - I Bailey
- Lancaster University, Lancaster, United Kingdom
| | - V A Baranov
- Joint Institute for Nuclear Research, Dubna, Russia
| | - E Barlas-Yucel
- University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - T Barrett
- Cornell University, Ithaca, New York, USA
| | - E Barzi
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - A Basti
- INFN, Sezione di Pisa, Pisa, Italy
- Università di Pisa, Pisa, Italy
| | | | - A Behnke
- Northern Illinois University, DeKalb, Illinois, USA
| | - M Berz
- Michigan State University, East Lansing, Michigan, USA
| | | | - H P Binney
- University of Washington, Seattle, Washington, USA
| | | | - P Bloom
- North Central College, Naperville, Illinois, USA
| | - J Bono
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - E Bottalico
- INFN, Sezione di Pisa, Pisa, Italy
- Università di Pisa, Pisa, Italy
| | - T Bowcock
- University of Liverpool, Liverpool, United Kingdom
| | - D Boyden
- Northern Illinois University, DeKalb, Illinois, USA
| | - G Cantatore
- INFN, Sezione di Trieste, Trieste, Italy
- Università di Trieste, Trieste, Italy
| | - R M Carey
- Boston University, Boston, Massachusetts, USA
| | - J Carroll
- University of Liverpool, Liverpool, United Kingdom
| | - B C K Casey
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - D Cauz
- INFN Gruppo Collegato di Udine, Sezione di Trieste, Udine, Italy
- Università di Udine, Udine, Italy
| | - S Ceravolo
- INFN, Laboratori Nazionali di Frascati, Frascati, Italy
| | | | - S P Chang
- Center for Axion and Precision Physics (CAPP)/Institute for Basic Science (IBS), Daejeon, Republic of Korea
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | | | - S Chappa
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - S Charity
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - R Chislett
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - J Choi
- Center for Axion and Precision Physics (CAPP)/Institute for Basic Science (IBS), Daejeon, Republic of Korea
| | - Z Chu
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
| | - T E Chupp
- University of Michigan, Ann Arbor, Michigan, USA
| | - M E Convery
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - A Conway
- Department of Physics, University of Massachusetts, Amherst, Massachusetts, USA
| | - G Corradi
- INFN, Laboratori Nazionali di Frascati, Frascati, Italy
| | - S Corrodi
- Argonne National Laboratory, Lemont, Illinois, USA
| | - L Cotrozzi
- INFN, Sezione di Pisa, Pisa, Italy
- Università di Pisa, Pisa, Italy
| | - J D Crnkovic
- Brookhaven National Laboratory, Upton, New York, USA
- University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- University of Mississippi, University, Mississippi, USA
| | - S Dabagov
- INFN, Laboratori Nazionali di Frascati, Frascati, Italy
| | | | - P T Debevec
- University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | | | - P Di Meo
- INFN, Sezione di Napoli, Napoli, Italy
| | | | - R Di Stefano
- INFN, Sezione di Napoli, Napoli, Italy
- Università di Cassino e del Lazio Meridionale, Cassino, Italy
| | - B Drendel
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - A Driutti
- INFN, Sezione di Trieste, Trieste, Italy
- Università di Udine, Udine, Italy
- University of Kentucky, Lexington, Kentucky, USA
| | - V N Duginov
- Joint Institute for Nuclear Research, Dubna, Russia
| | - M Eads
- Northern Illinois University, DeKalb, Illinois, USA
| | - N Eggert
- Cornell University, Ithaca, New York, USA
| | - A Epps
- Northern Illinois University, DeKalb, Illinois, USA
| | - J Esquivel
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - M Farooq
- University of Michigan, Ann Arbor, Michigan, USA
| | - R Fatemi
- University of Kentucky, Lexington, Kentucky, USA
| | - C Ferrari
- INFN, Sezione di Pisa, Pisa, Italy
- Istituto Nazionale di Ottica-Consiglio Nazionale delle Ricerche, Pisa, Italy
| | - M Fertl
- Institute of Physics and Cluster of Excellence PRISMA+, Johannes Gutenberg University Mainz, Mainz, Germany
- University of Washington, Seattle, Washington, USA
| | - A Fiedler
- Northern Illinois University, DeKalb, Illinois, USA
| | - A T Fienberg
- University of Washington, Seattle, Washington, USA
| | - A Fioretti
- INFN, Sezione di Pisa, Pisa, Italy
- Istituto Nazionale di Ottica-Consiglio Nazionale delle Ricerche, Pisa, Italy
| | - D Flay
- Department of Physics, University of Massachusetts, Amherst, Massachusetts, USA
| | - S B Foster
- Boston University, Boston, Massachusetts, USA
| | - H Friedsam
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - E Frlež
- University of Virginia, Charlottesville, Virginia, USA
| | - N S Froemming
- Northern Illinois University, DeKalb, Illinois, USA
- University of Washington, Seattle, Washington, USA
| | - J Fry
- University of Virginia, Charlottesville, Virginia, USA
| | - C Fu
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
| | - C Gabbanini
- INFN, Sezione di Pisa, Pisa, Italy
- Istituto Nazionale di Ottica-Consiglio Nazionale delle Ricerche, Pisa, Italy
| | - M D Galati
- INFN, Sezione di Pisa, Pisa, Italy
- Università di Pisa, Pisa, Italy
| | - S Ganguly
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
- University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - A Garcia
- University of Washington, Seattle, Washington, USA
| | - D E Gastler
- Boston University, Boston, Massachusetts, USA
| | - J George
- Department of Physics, University of Massachusetts, Amherst, Massachusetts, USA
| | | | - A Gioiosa
- INFN, Sezione di Pisa, Pisa, Italy
- Università del Molise, Campobasso, Italy
| | - K L Giovanetti
- Department of Physics and Astronomy, James Madison University, Harrisonburg, Virginia, USA
| | - P Girotti
- INFN, Sezione di Pisa, Pisa, Italy
- Università di Pisa, Pisa, Italy
| | - W Gohn
- University of Kentucky, Lexington, Kentucky, USA
| | - T Gorringe
- University of Kentucky, Lexington, Kentucky, USA
| | - J Grange
- Argonne National Laboratory, Lemont, Illinois, USA
- University of Michigan, Ann Arbor, Michigan, USA
| | - S Grant
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - F Gray
- Regis University, Denver, Colorado, USA
| | - S Haciomeroglu
- Center for Axion and Precision Physics (CAPP)/Institute for Basic Science (IBS), Daejeon, Republic of Korea
| | - D Hahn
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | | | - D Hampai
- INFN, Laboratori Nazionali di Frascati, Frascati, Italy
| | - F Han
- University of Kentucky, Lexington, Kentucky, USA
| | - E Hazen
- Boston University, Boston, Massachusetts, USA
| | - J Hempstead
- University of Washington, Seattle, Washington, USA
| | - S Henry
- University of Oxford, Oxford, United Kingdom
| | - A T Herrod
- University of Liverpool, Liverpool, United Kingdom
| | - D W Hertzog
- University of Washington, Seattle, Washington, USA
| | - G Hesketh
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - A Hibbert
- University of Liverpool, Liverpool, United Kingdom
| | - Z Hodge
- University of Washington, Seattle, Washington, USA
| | - J L Holzbauer
- University of Mississippi, University, Mississippi, USA
| | - K W Hong
- University of Virginia, Charlottesville, Virginia, USA
| | - R Hong
- Argonne National Laboratory, Lemont, Illinois, USA
- University of Kentucky, Lexington, Kentucky, USA
| | - M Iacovacci
- INFN, Sezione di Napoli, Napoli, Italy
- Università di Napoli, Napoli, Italy
| | | | - C Johnstone
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - J A Johnstone
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - P Kammel
- University of Washington, Seattle, Washington, USA
| | | | - M Karuza
- INFN, Sezione di Trieste, Trieste, Italy
- University of Rijeka, Rijeka, Croatia
| | - J Kaspar
- University of Washington, Seattle, Washington, USA
| | - D Kawall
- Department of Physics, University of Massachusetts, Amherst, Massachusetts, USA
| | - L Kelton
- University of Kentucky, Lexington, Kentucky, USA
| | - A Keshavarzi
- Department of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | - D Kessler
- Department of Physics, University of Massachusetts, Amherst, Massachusetts, USA
| | - K S Khaw
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, China
- University of Washington, Seattle, Washington, USA
| | | | - N V Khomutov
- Joint Institute for Nuclear Research, Dubna, Russia
| | - B Kiburg
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - M Kiburg
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
- North Central College, Naperville, Illinois, USA
| | - O Kim
- Center for Axion and Precision Physics (CAPP)/Institute for Basic Science (IBS), Daejeon, Republic of Korea
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - S C Kim
- Cornell University, Ithaca, New York, USA
| | - Y I Kim
- Center for Axion and Precision Physics (CAPP)/Institute for Basic Science (IBS), Daejeon, Republic of Korea
| | - B King
- University of Liverpool, Liverpool, United Kingdom
| | - N Kinnaird
- Boston University, Boston, Massachusetts, USA
| | | | - I Kourbanis
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - E Kraegeloh
- University of Michigan, Ann Arbor, Michigan, USA
| | - V A Krylov
- Joint Institute for Nuclear Research, Dubna, Russia
| | - A Kuchibhotla
- University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | | | - K R Labe
- Cornell University, Ithaca, New York, USA
| | - J LaBounty
- University of Washington, Seattle, Washington, USA
| | - M Lancaster
- Department of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | - M J Lee
- Center for Axion and Precision Physics (CAPP)/Institute for Basic Science (IBS), Daejeon, Republic of Korea
| | - S Lee
- Center for Axion and Precision Physics (CAPP)/Institute for Basic Science (IBS), Daejeon, Republic of Korea
| | - S Leo
- University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - B Li
- Argonne National Laboratory, Lemont, Illinois, USA
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
| | - D Li
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
| | - L Li
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
| | - I Logashenko
- Budker Institute of Nuclear Physics, Novosibirsk, Russia
| | | | - A Lucà
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - G Lukicov
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - G Luo
- Northern Illinois University, DeKalb, Illinois, USA
| | - A Lusiani
- INFN, Sezione di Pisa, Pisa, Italy
- Scuola Normale Superiore, Pisa, Italy
| | - A L Lyon
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - B MacCoy
- University of Washington, Seattle, Washington, USA
| | - R Madrak
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - K Makino
- Michigan State University, East Lansing, Michigan, USA
| | - F Marignetti
- INFN, Sezione di Napoli, Napoli, Italy
- Università di Cassino e del Lazio Meridionale, Cassino, Italy
| | | | - S Maxfield
- University of Liverpool, Liverpool, United Kingdom
| | - M McEvoy
- Northern Illinois University, DeKalb, Illinois, USA
| | - W Merritt
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | | | - J P Miller
- Boston University, Boston, Massachusetts, USA
| | - S Miozzi
- INFN, Sezione di Roma Tor Vergata, Roma, Italy
| | - J P Morgan
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - W M Morse
- Brookhaven National Laboratory, Upton, New York, USA
| | - J Mott
- Boston University, Boston, Massachusetts, USA
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - E Motuk
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - A Nath
- INFN, Sezione di Napoli, Napoli, Italy
- Università di Napoli, Napoli, Italy
| | - D Newton
- University of Liverpool, Liverpool, United Kingdom
| | - H Nguyen
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - M Oberling
- Argonne National Laboratory, Lemont, Illinois, USA
| | - R Osofsky
- University of Washington, Seattle, Washington, USA
| | - J-F Ostiguy
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - S Park
- Center for Axion and Precision Physics (CAPP)/Institute for Basic Science (IBS), Daejeon, Republic of Korea
| | - G Pauletta
- INFN Gruppo Collegato di Udine, Sezione di Trieste, Udine, Italy
- Università di Udine, Udine, Italy
| | - G M Piacentino
- INFN, Sezione di Roma Tor Vergata, Roma, Italy
- Università del Molise, Campobasso, Italy
| | - R N Pilato
- INFN, Sezione di Pisa, Pisa, Italy
- Università di Pisa, Pisa, Italy
| | - K T Pitts
- University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - B Plaster
- University of Kentucky, Lexington, Kentucky, USA
| | - D Počanić
- University of Virginia, Charlottesville, Virginia, USA
| | - N Pohlman
- Northern Illinois University, DeKalb, Illinois, USA
| | - C C Polly
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - M Popovic
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - J Price
- University of Liverpool, Liverpool, United Kingdom
| | - B Quinn
- University of Mississippi, University, Mississippi, USA
| | - N Raha
- INFN, Sezione di Pisa, Pisa, Italy
| | | | - E Ramberg
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - N T Rider
- Cornell University, Ithaca, New York, USA
| | - J L Ritchie
- Department of Physics, University of Texas at Austin, Austin, Texas, USA
| | - B L Roberts
- Boston University, Boston, Massachusetts, USA
| | - D L Rubin
- Cornell University, Ithaca, New York, USA
| | - L Santi
- INFN Gruppo Collegato di Udine, Sezione di Trieste, Udine, Italy
- Università di Udine, Udine, Italy
| | - D Sathyan
- Boston University, Boston, Massachusetts, USA
| | - H Schellman
- Northwestern University, Evanston, Illinois, USA
| | - C Schlesier
- University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - A Schreckenberger
- Boston University, Boston, Massachusetts, USA
- University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Physics, University of Texas at Austin, Austin, Texas, USA
| | - Y K Semertzidis
- Center for Axion and Precision Physics (CAPP)/Institute for Basic Science (IBS), Daejeon, Republic of Korea
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Y M Shatunov
- Budker Institute of Nuclear Physics, Novosibirsk, Russia
| | - D Shemyakin
- Budker Institute of Nuclear Physics, Novosibirsk, Russia
| | - M Shenk
- Northern Illinois University, DeKalb, Illinois, USA
| | - D Sim
- University of Liverpool, Liverpool, United Kingdom
| | - M W Smith
- INFN, Sezione di Pisa, Pisa, Italy
- University of Washington, Seattle, Washington, USA
| | - A Smith
- University of Liverpool, Liverpool, United Kingdom
| | - A K Soha
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - M Sorbara
- INFN, Sezione di Roma Tor Vergata, Roma, Italy
- Università di Roma Tor Vergata, Rome, Italy
| | - D Stöckinger
- Institut für Kern-und Teilchenphysik, Technische Universität Dresden, Dresden, Germany
| | - J Stapleton
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - D Still
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - C Stoughton
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - D Stratakis
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - C Strohman
- Cornell University, Ithaca, New York, USA
| | - T Stuttard
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - H E Swanson
- University of Washington, Seattle, Washington, USA
| | - G Sweetmore
- Department of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | | | - M J Syphers
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
- Northern Illinois University, DeKalb, Illinois, USA
| | - D A Tarazona
- Michigan State University, East Lansing, Michigan, USA
| | - T Teubner
- University of Liverpool, Liverpool, United Kingdom
| | | | - K Thomson
- University of Liverpool, Liverpool, United Kingdom
| | - V Tishchenko
- Brookhaven National Laboratory, Upton, New York, USA
| | - N H Tran
- Boston University, Boston, Massachusetts, USA
| | - W Turner
- University of Liverpool, Liverpool, United Kingdom
| | - E Valetov
- Lancaster University, Lancaster, United Kingdom
- Michigan State University, East Lansing, Michigan, USA
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, China
| | - D Vasilkova
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | | | - V P Volnykh
- Joint Institute for Nuclear Research, Dubna, Russia
| | - T Walton
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - M Warren
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - A Weisskopf
- Michigan State University, East Lansing, Michigan, USA
| | - L Welty-Rieger
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
| | - M Whitley
- University of Liverpool, Liverpool, United Kingdom
| | - P Winter
- Argonne National Laboratory, Lemont, Illinois, USA
| | - A Wolski
- University of Liverpool, Liverpool, United Kingdom
| | - M Wormald
- University of Liverpool, Liverpool, United Kingdom
| | - W Wu
- University of Mississippi, University, Mississippi, USA
| | - C Yoshikawa
- Fermi National Accelerator Laboratory, Batavia, Illinois, USA
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Antognini A, Ayres NJ, Belosevic I, Bondar V, Eggenberger A, Hildebrandt M, Iwai R, Kaplan DM, Khaw KS, Kirch K, Knecht A, Papa A, Petitjean C, Phillips TJ, Piegsa FM, Ritjoho N, Stoykov A, Taqqu D, Wichmann G. Demonstration of Muon-Beam Transverse Phase-Space Compression. Phys Rev Lett 2020; 125:164802. [PMID: 33124843 DOI: 10.1103/physrevlett.125.164802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 08/17/2020] [Accepted: 09/15/2020] [Indexed: 06/11/2023]
Abstract
We demonstrate efficient transverse compression of a 12.5 MeV/c muon beam stopped in a helium gas target featuring a vertical density gradient and crossed electric and magnetic fields. The muon stop distribution extending vertically over 14 mm was reduced to a 0.25 mm size (rms) within 3.5 μs. The simulation including cross sections for low-energy μ^{+}-He elastic and charge exchange (μ^{+}↔ muonium) collisions describes the measurements well. By combining the transverse compression stage with a previously demonstrated longitudinal compression stage, we can improve the phase space density of a μ^{+} beam by a factor of 10^{10} with 10^{-3} efficiency.
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Affiliation(s)
- A Antognini
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland
- Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - N J Ayres
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland
| | - I Belosevic
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland
| | - V Bondar
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland
| | - A Eggenberger
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland
| | - M Hildebrandt
- Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - R Iwai
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland
| | - D M Kaplan
- Illinois Institute of Technology, Chicago, Illinois 60616, USA
| | - K S Khaw
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland
| | - K Kirch
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland
- Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - A Knecht
- Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - A Papa
- Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
- Dipartimento di Fisica, Università di Pisa and INFN sez. Pisa, Largo B. Pontecorvo 3, 56127 Pisa, Italy
| | - C Petitjean
- Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - T J Phillips
- Illinois Institute of Technology, Chicago, Illinois 60616, USA
| | - F M Piegsa
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland
| | - N Ritjoho
- Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - A Stoykov
- Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - D Taqqu
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland
| | - G Wichmann
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland
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Antognini A, Crivelli P, Prokscha T, Khaw KS, Barbiellini B, Liszkay L, Kirch K, Kwuida K, Morenzoni E, Piegsa FM, Salman Z, Suter A. Muonium emission into vacuum from mesoporous thin films at cryogenic temperatures. Phys Rev Lett 2012; 108:143401. [PMID: 22540791 DOI: 10.1103/physrevlett.108.143401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Indexed: 05/31/2023]
Abstract
We report on muonium (Mu) emission into vacuum following μ(+) implantation in mesoporous thin SiO(2) films. We obtain a yield of Mu into vacuum of (38±4)% at 250 K and (20±4)% at 100 K for 5 keV μ(+) implantation energy. From the implantation energy dependence of the Mu vacuum yield we determine the Mu diffusion constants in these films: D(Mu)(250 K)=(1.6±0.1)×10(-4) cm(2)/s and D(Mu)(100 K)=(4.2±0.5)×10(-5) cm(2)/s. Describing the diffusion process as quantum mechanical tunneling from pore to pore, we reproduce the measured temperature dependence ∼T(3/2) of the diffusion constant. We extract a potential barrier of (-0.3±0.1) eV which is consistent with our computed Mu work function in SiO(2) of [-0.3,-0.9] eV. The high Mu vacuum yield, even at low temperatures, represents an important step toward next generation Mu spectroscopy experiments.
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Affiliation(s)
- A Antognini
- Institute for Particle Physics, ETH Zurich, Switzerland.
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Khaw KS, Ngan Kee WD, Chu CY, Ng FF, Tam WH, Critchley LAH, Rogers MS, Wang CC. Effects of different inspired oxygen fractions on lipid peroxidation during general anaesthesia for elective Caesarean section. Br J Anaesth 2010; 105:355-60. [PMID: 20576633 DOI: 10.1093/bja/aeq154] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND During general anaesthesia (GA) for Caesarean section (CS), fetal oxygenation is increased by administering an inspired oxygen fraction (Fi(o(2))) of 1.0. However, it is unclear whether such high Fi(o(2)) will increase oxygen free radical activity. METHODS We randomized 39 ASA I-II parturients undergoing elective CS under GA to receive 30% (Gp 30), 50% (Gp 50), or 100% (Gp 100) oxygen with nitrous oxide and sevoflurane adjusted to provide equivalent minimum alveolar concentration. Baseline maternal arterial blood before preoxygenation and maternal arterial, umbilical arterial and venous blood at delivery were sampled for assays of the by-product of lipid peroxidation, isoprostane, and for measurement of blood gases and oxygen content. RESULTS Maternal and umbilical isoprostane concentrations were similar among the three groups at delivery, despite significantly increased maternal and fetal oxygenation in Gp 100. However, paired comparisons of maternal delivery vs baseline concentration of isoprostane showed an increase at delivery for all groups [Gp 30: mean 342 (sd 210) vs 154 (65) pg ml(-1), P=0.016; Gp 50: 284 (129) vs 156 (79) pg ml(-1), P=0.009; Gp 100: 332 (126) vs 158 (68) pg ml(-1), P<0.001]. The magnitude of increase was similar in all three groups and independent of the Fi(o(2)) or duration after induction. CONCLUSIONS GA for CS is associated with a marked increase in free radical activity in the mother and baby. The mechanism is unclear but it is independent of the inspired oxygen in the anaesthetic mixture. Therefore, when 100% oxygen is administered with sevoflurane for GA, fetal oxygenation can be increased, without inducing an increase in lipid peroxidation.
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Affiliation(s)
- K S Khaw
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China.
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Abstract
The study objective was to show that fentanyl given five minutes prior to induction improved insertion conditions for the Classic Laryngeal Mask Airway. Previous work had shown fentanyl at 90 seconds to be unpredictable. A probit analysis design was used in which success/failure rates of different doses of fentanyl were measured and dose-response curves drawn from which the ED50 and ED95 with 95% confidence intervals were determined. Adult Chinese patients with American Society of Anesthesiologists physical status classification I or II and requiring anaesthesia for minor surgery with a laryngeal mask were recruited. They were randomly assigned to one of six dosage groups: 0.25, 0.5, 1.0, 1.5, 2.0 and 3.0 microg x kg1. Fentanyl was given prior to propofol 25 mg x kg(-1), and insertion was assessed 90 seconds later using six categories of patient response. Ninety-six patients, aged 18 to 63 years, were studied. The six dosage groups were similar As the fentanyl dose increased, fewer patients responded to insertion (P < 0.01). Dose-responses could be predicted for all categories, except resistance to insertion and laryngospasm. Probit analysis predicted an ED50 of 0.5 microg x kg(-1) and ED, of 7.5 microg x kg(-1) for ideal insertion conditions (i.e., no swallowing, gagging, body movement or laryngospasm). Commonly used fentanyl doses of 1 to 2 microg x kg(-1) only prevented patients responding to insertion in 70 to 80% of cases. When using propofol 2.5 mg x kg(-1), administering fentanyl five minutes before laryngeal mask insertion does not provide ideal insertion conditions in 95% of cases unless excessively large doses are used. An ideal dose of fentanyl that produces optimum insertion conditions could not be determined.
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Affiliation(s)
- T H K Wong
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong
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Ngan Kee WD, Khaw KS, Lau TK, Ng FF, Chui K, Ng KL. Randomised double-blinded comparison of phenylephrine vs ephedrine for maintaining blood pressure during spinal anaesthesia for non-elective Caesarean section*. Anaesthesia 2008; 63:1319-26. [DOI: 10.1111/j.1365-2044.2008.05635.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Khaw KS, Wang CC, Ngan Kee WD, Tam WH, Ng FF, Critchley LAH, Rogers MS. Supplementary oxygen for emergency Caesarean section under regional anaesthesia. Br J Anaesth 2008; 102:90-6. [PMID: 19011261 DOI: 10.1093/bja/aen321] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Controversy still exists if the administration of supplementary oxygen to patients having emergency Caesarean section (CS) under regional anaesthesia is beneficial or potentially harmful. Therefore, in a prospective double-blinded study, we randomized patients having emergency CS under regional anaesthesia to receive either air or 60% oxygen until delivery and compared the effects on fetal oxygenation and lipid-peroxidation in the mother and baby. METHODS We recruited 131 women having emergency CS under regional anaesthesia. Either 21% (air group) or 60% oxygen (oxygen group) was administered using a Venturi-type facemask until delivery. We compared the oxygen exposure duration, umbilical arterial (UA) and venous (UV) blood gases and oxygen content, and plasma concentration of 8-isoprostane. Subanalysis was performed according to whether or not fetal compromise was considered present. RESULTS Data from 125 patients were analysed. For the oxygen group vs the air group, there were greater values for UA PO(2) [mean 2.2 (SD 0.5) vs 1.9 (0.6) kPa, P=0.01], UA O(2) content [6.6 (2.5) vs 4.9 (2.8) ml dl(-1), P=0.006], UV PO(2) [3.8 (0.8) vs 3.2 (0.8) kPa, P<0.0001], and UV O(2) content [12.9 (3.5) vs 10.4 (3.8) ml dl(-1), P=0.001]. There was no difference between the groups in maternal, UA, or UV 8-isoprostane concentration. Apgar scores and UA pH were similar between the groups. Similar changes were observed regardless of whether fetal compromise was considered present (n=37) or not (n=88). CONCLUSIONS Breathing 60% oxygen during emergency CS under regional anaesthesia increased fetal oxygenation with no associated increase in lipid-peroxidation in the mother or fetus.
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Affiliation(s)
- K S Khaw
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China.
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Khaw KS, Ngan Kee WD, Tam YH, Wong MK, Lee SWY. Survey and evaluation of modified oxygen delivery devices used for suspected severe acute respiratory syndrome and other high-risk patients in Hong Kong. Hong Kong Med J 2008; 14:27-31. [PMID: 18941271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023] Open
Affiliation(s)
- K S Khaw
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China.
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Ngan Kee WD, Tam YH, Khaw KS, Ng FF, Critchley LA, Karmakar MK. Closed-loop feedback computer-controlled infusion of phenylephrine for maintaining blood pressure during spinal anaesthesia for caesarean section: a preliminary descriptive study*. Anaesthesia 2007; 62:1251-6. [DOI: 10.1111/j.1365-2044.2007.05257.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
Probit analysis was used to predict an optimal dose of fentanyl, co-administered with propofol 2.5 mg.kg(-1), when inserting the laryngeal mask airway. In all, 21 male and 54 female healthy Chinese patients, aged 18-63 years, requiring anaesthesia for minor surgery were recruited. They were assigned to one of five groups: placebo, 0.5, 1.0, 1.5 and 2.0 microg.kg(-1). Insertion was performed 90 s after administration and insertion conditions assessed using a six-category score. Dose-response curves could only be drawn for swallowing and movement categories, and only the ED(50) could be predicted with certainty. To provide optimal conditions in over 95% of patients, fentanyl doses well above the clinical range were required. A standard fentanyl dose of 1 mug.kg(-1), co-administered with propofol 2.5 mg.kg(-1), provided optimal conditions in 65% of cases. Ninety seconds may have been insufficient time for fentanyl to reach its peak effect.
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Affiliation(s)
- C M Wong
- Department of Anaesthesia & Intensive Care, Prince of Wales Hospital, Shatin, New Territories, Hong Kong
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Critchley LAH, Khaw KS. Bougie assisted insertion of ProSeal LMA. Anaesth Intensive Care 2006; 34:514-5. [PMID: 16913354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
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Ngan Kee WD, Khaw KS, Ng FF. Comparison of phenylephrine infusion regimens for maintaining maternal blood pressure during spinal anaesthesia for Caesarean section †. Br J Anaesth 2004; 92:469-74. [PMID: 14977792 DOI: 10.1093/bja/aeh088] [Citation(s) in RCA: 177] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND During spinal anaesthesia for Caesarean section, the optimal phenylephrine regimen and the optimal blood pressure (BP) to which it should be titrated are undetermined. The ideal regimen would balance efficacy for maintaining uteroplacental perfusion pressure against potential for uteroplacental vasoconstriction, both of which may affect fetal acid-base status. We compared phenylephrine infusion regimens based on three different BP thresholds. METHODS After intrathecal injection, we infused phenylephrine 100 microg min(-1) for 2 min. Then, until delivery, we infused phenylephrine whenever systolic BP (SBP), measured every 1 min, was below a randomly assigned percentage of baseline: 100% (Group 100, n=25), 90% (Group 90, n=25) or 80% (Group 80, n=24). We compared umbilical blood gases, Apgar scores and maternal haemodynamics and symptoms. RESULTS Patients in Group 100 had fewer episodes [median 0 (range 0-8)] of hypotension (SBP <80% baseline) compared with Group 80 [5 (0-18)] and Group 90 [2 (0-7)] (P<0.001 in each instance). Total dose of phenylephrine was greater in Group 100 [median 1520 microg (interquartile range 1250-2130 microg)] compared with Group 90 [1070 (890-1360) microg] and Group 80 [790 (590-950) microg]. Umbilical arterial pH was greater in Group 100 [mean 7.32 (95% confidence interval 7.31-7.34)] than in Group 80 [7.30 (7.28-7.31)] (P=0.034). No patient had umbilical arterial pH <7.2. In Group 100, 1/24 (4%) patients had nausea or vomiting compared with 4/25 (16%) in Group 90 and 10/25 (40%) in Group 80 (P=0.006). CONCLUSIONS For optimal management, phenylephrine should be titrated to maintain maternal BP at near-baseline values.
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Affiliation(s)
- W D Ngan Kee
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China.
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Khaw KS, Ngan Kee WD, Lee A, Wang CC, Wong ASY, Ng F, Rogers MS. Supplementary oxygen for elective Caesarean section under spinal anaesthesia: useful in prolonged uterine incision-to-delivery interval? †. Br J Anaesth 2004; 92:518-22. [PMID: 15013959 DOI: 10.1093/bja/aeh092] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The benefit of administering supplementary oxygen during elective Caesarean section under regional anaesthesia is controversial. It has been hypothesized that its use would improve fetal oxygenation in the event of a prolonged uterine incision-to-delivery (U-D) interval. Our aim was to test this hypothesis in a prospective, randomized, double-blinded, controlled study. METHODS We allocated randomly 204 women having elective Caesarean section under spinal anaesthesia to breathe 21, 40 or 60% oxygen. We recorded the U-D interval, umbilical arterial (UA) and venous (UV) blood gases and oxygen content and Apgar scores. Subgroup analysis was performed according to whether the U-D interval was prolonged (>180 s) or not. RESULTS The U-D interval was <180 s in 159 patients and >180 s in 45 patients. There were no differences in UV or UA blood gases, oxygen content or Apgar scores between cases with and without a prolonged U-D interval. In cases without a prolonged U-D interval, administering 60% oxygen increased UV PO(2) (mean 4.3 (SD 1.1) vs 3.7 (1.0) kPa, P=0.003) and oxygen content (14.4 (3.3) vs 12.9 (2.7) ml dl(-1), P=0.007) compared with air. In cases with a prolonged U-D interval, administering 60% oxygen increased UV PO(2) (4.6 (0.6) vs 3.9 (0.8) kPa, P=0.019) compared with air but there was no difference in UV oxygen content. There was no increase in the UV PO(2) or oxygen content when 40% oxygen was administered compared with air. CONCLUSIONS Supplementary oxygen did not increase fetal oxygenation in cases where the U-D interval was prolonged. Our data do not support the routine administration of supplementary oxygen during elective Caesarean section for this purpose.
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Affiliation(s)
- K S Khaw
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong, China.
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Ngan Kee WD, Khaw KS, Ma KC, Wong ASY, Lee BB. Randomized, double-blind comparison of different inspired oxygen fractions during general anaesthesia for Caesarean section. Br J Anaesth 2002; 89:556-61. [PMID: 12393355 DOI: 10.1093/bja/aef203] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The optimal inspired oxygen fraction FI(O(2)) for fetal oxygenation during general anaesthesia for Caesarean section is not known. METHODS We randomized patients having elective Caesarean section to receive one of the following: FI(O(2)) 0.3, FI(N(2))(O) 0.7 and end-tidal sevoflurane 0.6% (Group 30, n=20); FI(O(2)) 0.5, FI(N(2))(O) 0.5 and end-tidal sevoflurane 1.0% (Group 50, n=20), or FI(O(2)) 1.0 and end-tidal sevoflurane 2.0% (Group 100, n=20) until delivery. Neonatal outcome was compared biochemically and clinically. RESULTS At delivery, for umbilical venous blood, mean PO(2) was greater in Group 100 (7.6 (SD 3.7) kPa) compared with both Group 30 (4.0 (1.1) kPa, P<0.0001) and Group 50 (4.7 (0.9) kPa, P=0.002) and oxygen content was greater in Group 100 (17.2 (1.6) ml dl(-1)) compared with both Group 30 (12.8 (3.6) ml dl(-1), P=0.0001) and Group 50 (13.8 (2.6) ml dl(-1), P=0.0001). For umbilical arterial blood, PO(2) was greater in Group 100 (3.2 (0.4) kPa) compared with Group 30 (2.4 (0.7) kPa, P=0.003), and in Group 50 (2.9 (0.8) kPa) compared with Group 30 (2.4 (0.7) kPa, P=0.04); oxygen content was greater in Group 100 (10.8 (3.5) ml dl(-1)) than in Group 30 (7.0 (3.0) ml dl(-1), P<0.01). Apgar scores, neonatal neurologic and adaptive capacity scores, and maternal arterial plasma concentrations of epinephrine and norepinephrine before induction and at delivery were similar among groups. No patient reported intraoperative awareness. CONCLUSIONS Use of FI(O(2)) 1.0 during general anaesthesia for elective Caesarean section increased fetal oxygenation.
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Affiliation(s)
- W D Ngan Kee
- Department of Anaesthesia and Intensive Care, Department of Paediatrics, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China
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Khaw KS, Wang CC, Ngan Kee WD, Pang CP, Rogers MS. Effects of high inspired oxygen fraction during elective caesarean section under spinal anaesthesia on maternal and fetal oxygenation and lipid peroxidation. Br J Anaesth 2002; 88:18-23. [PMID: 11883375 DOI: 10.1093/bja/88.1.18] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Oxygen supplementation is given routinely to parturients undergoing Caesarean section under regional anaesthesia. While the aim is to improve fetal oxygenation, inspiring a high oxygen fraction (FIO2) can also increase free radical activity and lipid peroxidation in both the mother and baby. In this prospective, randomized, double-blind study, we investigated the effect of high inspired oxygen fraction (FIO2) on maternal and fetal oxygenation and oxygen free radical activity in parturients having Caesarean section under spinal anaesthesia. METHODS Forty-four healthy parturients were randomized to breathe either 21% (air group) or 60% oxygen (oxygen group) intraoperatively via a ventimask. Maternal arterial blood was collected at 5-min intervals from baseline until delivery, and umbilical arterial and venous blood was collected at delivery. We measured blood gases and the products of lipid peroxidation (8-isoprostane, malondialdehyde (MDA), hydroperoxide (OHP)) and purine metabolites. RESULTS At delivery, the oxygen group had greater maternal arterial PO2 [mean 30.0 (SD 6.3) vs 14.2 (1.9) kPa; mean difference 15.8 kPa, 95% confidence interval 12.9-18.7 kPa, P<0.001] and greater umbilical venous PO2 [4.8 (1.0) vs 4.0 (1.4) kPa; mean difference 0.8 kPa, 95% confidence interval 0.0-1.5 kPa, P=0.04] compared with the air group. Maternal and umbilical plasma concentrations of lipid peroxides (8-isoprostane, MDA, OHP) were greater in the oxygen group than in the air group (P<0.05). CONCLUSIONS We conclude that breathing high FIO2 modestly increased fetal oxygenation but caused a concomitant increase in oxygen free radical activity in both mother and fetus.
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Affiliation(s)
- K S Khaw
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, China
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Abstract
BACKGROUND The dose-response relation for spinal ropivacaine is undetermined, and there are few data available for obstetric patients. METHODS In a prospective, randomized, double-blind investigation, the authors studied 72 patients undergoing elective cesarean delivery. An epidural catheter was placed at the L2-L3 vertebral interspace. Lumbar puncture was then performed at the L3-L4 vertebral interspace, and patients were randomized to receive a dose of spinal ropivacaine diluted to 3 ml with normal saline: 10 mg (n = 12), 15 mg (n = 20), 20 mg (n = 20), or 25 mg (n = 20). Sensory changes assessed by ice and pin prick and motor changes assessed by modified Bromage score were recorded at timed intervals. A dose was considered effective if an upper sensory level to pin prick of T7 or above was achieved and epidural supplementation was not required intraoperatively. RESULTS Anesthesia was successful in 8.3, 45, 70, and 90% of the 10-, 15-, 20-, and 25-mg groups, respectively. A sigmoid dose-response curve and a probit log dose-response plot were obtained, and the authors determined the ED50 (95% confidence interval) to be 16.7 (14.1-18.8) mg and the ED95 (95% confidence interval) to be 26.8 (23.6-34.1) mg. Duration of sensory and motor block and degree of motor block, but not onset of anesthesia, were positively related to dose. CONCLUSIONS The ED50 and estimated ED95 for spinal ropivacaine were 16.7 and 26.8 mg, respectively. Ropivacaine is a suitable agent for spinal anesthesia for cesarean delivery.
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Affiliation(s)
- K S Khaw
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, SAR, China.
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Ngan Kee WD, Khaw KS, Lee BB, Ng FF, Wong MM. Randomized controlled study of colloid preload before spinal anaesthesia for caesarean section. Br J Anaesth 2001; 87:772-4. [PMID: 11878530 DOI: 10.1093/bja/87.5.772] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We randomized women having elective Caesarean section to receive either no preload (control group, n=33) or 4% gelatin solution (Gelofusine) 15 ml kg(-1) (colloid group, n=35) i.v. before spinal anaesthesia. Intravenous metaraminol was titrated at 0.25-0.75 mg min(-1) to maintain systolic arterial pressure (SAP) in the target range 90-100% of baseline after the spinal injection. The control group required more vasopressor in the first 10 min [median 1.7 (range 0-2.9) mg vs 1.4 (0-2.8), P=0.02] at a greater maximum infusion rate [0.5 (0-0.75) vs 0.25 (0-0.5) mg min(-1), P=0.0005] and had a lower minimum SAP [90 (51-109) vs 101 (75-127) mm Hg, P=0.006] than the colloid group. Nausea was less frequent in the colloid group (6 vs 24%) but neonatal outcome was similar in the two groups. Colloid preload improved haemodynamic stability but did not affect neonatal outcome when arterial pressure was maintained with an infusion of metaraminol during spinal anaesthesia for Caesarean section.
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Affiliation(s)
- W D Ngan Kee
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin
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Ngan Kee WD, Khaw KS, Lee BB, Wong MM, Ng FF. Metaraminol infusion for maintenance of arterial blood pressure during spinal anesthesia for cesarean delivery: the effect of a crystalloid bolus. Anesth Analg 2001; 93:703-8. [PMID: 11524344 DOI: 10.1097/00000539-200109000-00033] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We randomly allocated women having elective cesarean delivery to receive either no bolus (Control Group, n = 31) or 20 mL/kg lactated Ringer's solution (Bolus Group, n = 35) IV before spinal anesthesia. An infusion of metaraminol started at 0.25 mg/min was titrated to maintain systolic arterial blood pressure in the target range 90%-100% of baseline. The total dose of metaraminol required up to the time of uterine incision was similar between the Control Group and the Bolus Group (3.62 +/- 1.20 vs 3.27 +/- 1.39 mg, P = 0.3). However, the Control Group required more metaraminol in the first 5 min (1.29 +/- 0.60 vs 0.96 +/- 0.58 mg, P = 0.025) and a faster maximum infusion rate (0.45 +/- 0.20 vs 0.32 +/- 0.13 mg/min, P = 0.002) compared with the Bolus Group. There was no difference between groups in regards to changes in systolic arterial blood pressure or heart rate over time, or maternal or neonatal outcome. We conclude that when metaraminol is used to maintain arterial pressure during spinal anesthesia for cesarean delivery, crystalloid bolus is not essential provided that sufficient vasopressor is given in the immediate postspinal period.
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Affiliation(s)
- W D Ngan Kee
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China.
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Ngan Kee WD, Lau TK, Khaw KS, Lee BB. Comparison of metaraminol and ephedrine infusions for maintaining arterial pressure during spinal anesthesia for elective cesarean section. Anesthesiology 2001; 95:307-13. [PMID: 11506099 DOI: 10.1097/00000542-200108000-00009] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Although ephedrine is usually recommended as the first-line vasopressor in obstetrics, its superiority over other vasopressors has not been proven in humans. METHODS In a double-blind study, the authors randomized women having elective cesarean section with spinal anesthesia to receive an intravenous infusion of ephedrine, starting at 5 mg/min (n = 25), or metaraminol, starting at 0.25 mg/min (n = 25), titrated to maintain systolic arterial pressure in the target range 90-100% of baseline. Umbilical cord gases, maternal hemodynamics, uterine artery puLsatility index, and Apgar scores were compared. RESULTS Systolic arterial pressure was maintained more closely in the target range in the metaraminol group compared with the ephedrine group. In the metaraminol group, umbilical arterial pH was greater (median and interquartile range, 7.31 and 7.31-7.33 vs. 7.24 and 7.14-7.29; P < 0.0001), and umbilical venous pH was greater (7.36 and 7.35-7.38 vs. 7.33 and 7.26-7.34; P < 0.0001) compared with the ephedrine group. No patient in the metaraminol group had umbilical arterial pH less than 7.2, compared with nine patients (39%) in the ephedrine group (P = 0.0005). Apgar scores were similar between groups. Changes in uterine artery pulsatility index were similar between groups. CONCLUSIONS When used by infusion to maintain arterial pressure during spinal anesthesia for cesarean section, metaraminol was associated with less neonatal acidosis and more closely controlled titration of arterial pressure compared with ephedrine.
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Affiliation(s)
- W D Ngan Kee
- Department of Anaesthesia and Intensive Care, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin.
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Lam DT, Ngan Kee WD, Khaw KS. Extension of epidural blockade in labour for emergency Caesarean section using 2% lidocaine with epinephrine and fentanyl, with or without alkalinisation. Anaesthesia 2001; 56:790-4. [PMID: 11493247 DOI: 10.1046/j.1365-2044.2001.02058-4.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In a randomised, double-blind study, we investigated rapid extension of epidural analgesia to surgical anaesthesia for emergency Caesarean section. Parturients receiving epidural analgesia in labour who subsequently required Caesarean section were given a test dose of 3 ml lidocaine 2% with epinephrine 1 : 200 000, followed 3 min later by 12 ml lidocaine 2% with epinephrine 1 : 200 000 and fentanyl 75 microg, to which was added 1.2 ml sodium bicarbonate 8.4% (bicarbonate group; n = 20) or saline (saline group; n = 20). Mean (SD [range]) time to surgical anaesthesia was less in the bicarbonate group (5.2 (1.5) [2-8] min) than the saline group (9.7 (1.6) [6-12] min; mean difference 4.5 min (95% CI 3.5-5.5) min; p < 0.001). Maternal side-effects and neonatal outcome were similar between groups. We conclude that pH-adjusted lidocaine 2% with epinephrine and fentanyl is effective for rapidly establishing surgical anaesthesia in patients with a functioning epidural catheter for labour who require emergency Caesarean section.
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Affiliation(s)
- D T Lam
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China
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Affiliation(s)
- W D Ngan Kee
- Department of Anaesthesia and Intensive Care, Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, China.
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Ngan Kee WD, Khaw KS, Lee BB, Lau TK, Gin T. A dose-response study of prophylactic intravenous ephedrine for the prevention of hypotension during spinal anesthesia for cesarean delivery. Anesth Analg 2000; 90:1390-5. [PMID: 10825326 DOI: 10.1097/00000539-200006000-00024] [Citation(s) in RCA: 140] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
UNLABELLED We performed a randomized, double-blinded dose-finding study of IV ephedrine for prophylaxis for hypotension in 80 women who received an IV crystalloid preload and spinal anesthesia for elective cesarean delivery. One minute after the intrathecal injection, patients were given saline control or ephedrine 10, 20, or 30 mg IV for 30 s. Systolic arterial pressure (SAP) in the first 12 min after the spinal injection was greater in the 30-mg group compared with other groups (P < 0.05). Hypotension occurred in 7 patients (35%) in the 30-mg group compared with 19 (95%), 17 (85%), and 16 (80%) patients in the control and 10- and 20-mg groups, respectively (P < 0.0001). Maximum decrease in SAP was smaller in the 30-mg group (mean lowest SAP 87% of baseline, range 58%-105%) compared with other groups (P < 0.01). Reactive hypertension occurred in 9 patients (45%) in the 30-mg group (mean highest SAP 120% of baseline, range 104%-143%) compared with 2 (10%), 1 (5%), and 5 (25%) patients in the other groups (P = 0.009). Heart rate changes, total ephedrine requirement, incidence of nausea and vomiting, and neonatal outcome were similar among groups. The proportion of patients with umbilical arterial pH < 7.2 was 10.5%, 25%, 42%, and 22% in the control, 10-, 20-, and 30-mg groups, respectively (P = 0. 12). We conclude that the smallest effective dose of ephedrine to reduce the incidence of hypotension was 30 mg. However, this dose did not completely eliminate hypotension, nausea and vomiting, and fetal acidosis, and it caused reactive hypertension in some patients. IMPLICATIONS We investigated different doses of IV ephedrine as prophylaxis for hypotension during spinal anesthesia for cesarean delivery and found that the smallest effective dose was 30 mg. However, this dose did not completely eliminate hypotension, caused reactive hypertension in some patients, and did not improve neonatal outcome.
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Affiliation(s)
- W D Ngan Kee
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China
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Abstract
PURPOSE Meperidine has local anesthetic properties and, therefore, when given epidurally it has the potential to cause hemodynamic changes. Our objective was to study the hemodynamic effects of an analgesic dose of epidural meperidine (50 mg) in 34 ASA 1-2 term parturients scheduled for elective Cesarean section under epidural anesthesia. METHODS A lumbar epidural catheter was inserted and patients lay in the supine left wedge position. Intravenous fluid preload was withheld, and hemodynamic measurements comprising of mean arterial pressure, cardiac output and heart rate were made using automatic oscillotonometry (Dinamap 1486SX) and transthoracic electrical bioimpedance (Bomed NCCOM3). Following baseline measurements, the hemodynamic effects of sequential epidural injection of first, 10 ml saline, and 20 min thereafter, 50 mg meperidine diluted to 10 ml with saline, were recorded. Sensory blockade was assessed following each injection using loss of temperature discrimination to ice. Paired Student t tests were used to compare changes in hemodynamic variables. RESULTS Epidural meperidine produced a small increase from the saline values in the mean (SD) cardiac output of 5.81 +/-1.44 to 6.04+/-1.54 L x min(-1) (P<0.05), and mean arterial pressure of 77.1+/-8.8 to 79.3+/-9.9 mm Hg (P<0.05). Sensory changes, the upper level of which ranged from L1 to T1, were detected in 94% of patients given epidural meperidine. Epidural saline injection had no such hemodynamic effects, but produced a detectable sensory level in two patients. CONCLUSION Epidural meperidine, 50 mg, caused minimal hemodynamic changes in term parturients.
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Affiliation(s)
- K S Khaw
- Department of Anaesthesia and Intensive Care, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Peoples Republic of China.
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Ngan Kee WD, Shen J, Chiu AT, Lok I, Khaw KS. Combined spinal-epidural analgesia in the management of labouring parturients with mitral stenosis. Anaesth Intensive Care 1999; 27:523-6. [PMID: 10520396 DOI: 10.1177/0310057x9902700516] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We report the use of combined spinal-epidural analgesia during labour in three parturients with moderately severe mitral stenosis. In each case, rapid analgesia was achieved using intrathecal fentanyl 25 micrograms without major haemodynamic changes. Maintenance analgesia was then established gradually using a dilute epidural infusion of bupivacaine 0.1% and fentanyl 0.0002%, with the avoidance of large or rapid boluses of local anaesthetic. Supplementary analgesia in the latter stages of labour was provided using slow epidural boluses of fentanyl, with or without a low concentration of bupivacaine, which was sufficient to allow controlled instrumental deliveries. We conclude that combined spinal-epidural analgesia is a useful technique for providing analgesia and maintaining haemodynamic stability in parturients with mitral stenosis.
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Affiliation(s)
- W D Ngan Kee
- Department of Anaesthesia and Intensive Care, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong
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Abstract
In a randomised, double-blind study, we compared a combination of morphine and alfentanil with morphine alone for patient-controlled analgesia (PCA) after Caesarean section under spinal anaesthesia. After surgery, patients were randomly allocated to receive PCA with a bolus dose of either morphine 0.75 mg plus alfentanil 0.125 mg (Group MA, n = 40) or morphine 1.5 mg alone (Group M, n = 37) with a lockout interval of 8 min and no hourly dose limit. Clinical assessments were made in the first 24 h, after which patients completed a written questionnaire. There were no differences between groups in PCA usage or visual analogue scale pain scores measured at 2, 4, 6 and 24 h. There was a low incidence of side-effects in both groups. In the questionnaire, patients in Group MA scored higher compared with Group M when asked to grade speed of onset and effectiveness of analgesia after a PCA bolus; there were no differences in grading for duration of analgesia or overall patient satisfaction. Addition of alfentanil to morphine may have advantages for PCA.
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Affiliation(s)
- W D Ngan Kee
- Associate Professor, Department of Anaesthesia, The Chinese University of Hong Kong, China
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Abstract
Open heart operations in patients with osteogenesis imperfecta are associated with increased morbidity and mortality resulting from tissue friability and bone brittleness. We used a ministernotomy approach for aortic valve replacement in a patient with osteogenesis imperfecta, with clear benefits and a satisfactory outcome.
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Affiliation(s)
- M B Izzat
- Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin.
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Izzat MB, Khaw KS, Atassi W, Yim AP, Wan S, El-Zufari MH. Routine intraoperative angiography improves the early patency of coronary grafts performed on the beating heart. Chest 1999; 115:987-90. [PMID: 10208197 DOI: 10.1378/chest.115.4.987] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
OBJECTIVES The techniques of performing coronary revascularization without cardiopulmonary bypass are rapidly evolving. However, concern remains regarding the accuracy of coronary artery anastomoses performed on the beating heart. This report reviews the use of intraoperative angiography in the critical appraisal of "off-pump" coronary artery bypass graft (CABG) surgery. PATIENTS Intraoperative angiography was performed in 24 consecutive patients undergoing CABG surgery without cardiopulmonary bypass. In all, 24 left internal mammary artery (LIMA) grafts and 18 saphenous vein bypass grafts were assessed for patency, anastomosis quality, distal and proximal runoff, and correct placement. RESULTS All of the saphenous vein-to-coronary artery anastomoses were widely patent, although two patients (8%) required revision of their LIMA grafts on the basis of angiographic findings. CONCLUSION Intraoperative angiography permits the surgeon to immediately appraise the CABG and to revise, if necessary, any graft abnormality, thus potentially eliminating the need for early repeated surgery. The practice of routine intraoperative angiography is likely to improve the outcome of CABG surgery on the beating heart.
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Affiliation(s)
- M B Izzat
- Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong.
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Abstract
BACKGROUND While the operative technique of left ventricular volume reduction (LVVR) is rapidly becoming standardized, the optimal perioperative management strategy is yet to be determined. We present our experience with the care of patients undergoing LVVR. METHODS LVVR was performed in 21 patients (mean age = 65.5 years) with congestive heart failure. Our management strategy was initially based on afterload reduction with sodium nitroprusside, but was later modified to include routine preoperative intra-aortic balloon support, normothermic cardiopulmonary bypass, antegrade intermittent warm blood cardioplegia, and postoperative support with phosphodiesterase-III inhibitors. Hemodynamic manipulations are aimed to attain systemic vascular resistance between 600 and 800 dyne/sec per cm(-5) and the lowest mean blood pressure that is able to maintain satisfactory systemic perfusion. Postoperatively, aggressive antifailure medical therapy with a high dose of angiotensin converting enzyme inhibitors, nitrates, and diuretics was initiated early and maintained indefinitely. RESULTS Using this approach, postoperative progress was characterized by hemodynamic stability. IABP support was used for 59.6+/-9 hours following surgery, and inotropic support for 103+/-12 hours. In our series there were four (19%) in-hospital deaths, two of which were related to heart failure. CONCLUSION The described approach is associated with an acceptable early outcome. However, further advances in myocardial protection methods and pharmacological and mechanical support techniques are necessary for a wider adoption of this procedure.
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Affiliation(s)
- M B Izzat
- Division of Cardiothoracic Surgery, The Chinese University of Hong Kong.
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Abstract
We have investigated the addition of adrenaline to pethidine for patient-controlled epidural analgesia after elective Caesarean section. In a randomised, double-blind study, patients received patient-controlled epidural analgesia for 24 h using pethidine 5 mg.ml-1 with adrenaline 5 micrograms.ml-1 (adrenaline group, n = 40) or pethidine 5 mg.ml-1 without adrenaline (plain group, n = 38). Visual analogue scale pain scores at rest and on coughing measured 2 h, 6 h and 24 h after surgery were similar between the two groups. There was a trend towards lower mean total consumption of pethidine in the adrenaline group (231.5 mg; SD 140.5 mg) compared with the plain group (289.5 mg; SD 139.5 mg; p = 0.071). Patients in the adrenaline group had higher visual analogue scale scores for nausea at 2 h and 24 h and higher scores for pruritus at 2 h compared with the plain group. Addition of adrenaline to pethidine for patient-controlled epidural analgesia does not appear to have significant clinical advantages.
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Affiliation(s)
- W D Ngan Kee
- Department of Anaesthesia and Intensive Care, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, People's Republic of China
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Abstract
OBJECTIVES New minimally invasive approaches for cardiac surgical procedures are constantly being developed in the hope of decreasing patient morbidity and enhancing the postoperative recovery. This report reviews the use of an upper T mini-sternotomy approach to aortic valve surgery. PATIENTS Nine consecutive nonselected patients (5 men, 4 women, mean age, 66 years) underwent isolated aortic valve replacement with the use of this approach. Two patients had isolated aortic valve stenosis, three had isolated aortic valve incompetence, and four patients had mixed aortic valve disease. RESULTS In all cases, an excellent view of the aortic valve was obtained, aortic valve replacement with a bileaflet mechanical prostheses was performed, and no intraoperative difficulties were encountered. Mean aortic cross-clamp time was 83 min and mean cardiopulmonary bypass perfusion time was 97 min. All patients were extubated in the operating room at the end of the surgical procedure, and there were no postoperative complications. All patients were discharged home on postoperative day 3, and there were no late complications. CONCLUSION Through an upper T mini-sternotomy, aortic valve surgery can be performed in the conventional manner using standard surgical instruments with no alteration in cardiopulmonary bypass and myocardial protection routines. With this method, postoperative pain is reduced and patient recovery is expeditious.
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Affiliation(s)
- M B Izzat
- Department of Surgery, Prince of Wales Hospital, Shatin, NT, Hong Kong.
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Thorniley MS, Khaw KS, Balogun E, Simpkin S, Shurey C, Sammut IA, Green CJ. Measurement of cerebral oxygenation and haemodynamics during haemorrhage/fluid replacement. Adv Exp Med Biol 1998; 428:391-6. [PMID: 9500076 DOI: 10.1007/978-1-4615-5399-1_56] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- M S Thorniley
- Department of Surgical Research, Northwick Park Institute for Medical Research, Northwick Park Hospital, Harrow, Middlesex, United Kingdom
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Ngan Kee WD, Khaw KS, Ma ML, Mainland PA, Gin T. Postoperative analgesic requirement after cesarean section: a comparison of anesthetic induction with ketamine or thiopental. Anesth Analg 1997; 85:1294-8. [PMID: 9390597 DOI: 10.1097/00000539-199712000-00021] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
UNLABELLED In a randomized, double-blind study, we compared postoperative pain and analgesic requirement in patients who underwent elective cesarean section under general anesthesia induced with thiopental 4 mg/kg (n = 20) or ketamine 1 mg/kg (n = 20). Anesthesia was maintained with nitrous oxide and isoflurane. Postoperative analgesia was provided by patient-controlled analgesia (PCA) using morphine. Median (range) time to first PCA demand was greater in the ketamine group (28 [3-134] min) compared with the thiopental group (20.5 [3-60] min; P = 0.04). Median (range) morphine consumption over 24 h was less in the ketamine group (24.3 [3-41] mg) compared with the thiopental group (35 [4-67] mg; P = 0.017). Visual analog scale pain scores were similar between groups. No patients had recall of intraoperative events or unpleasant dreams. Two patients in the thiopental group and one patient in the ketamine group had pleasant intraoperative dreams. Apgar scores were similar between groups. Median umbilical venous pH was higher (7.33 vs 7.31; P = 0.04) and attributable to lower median umbilical venous Pco2 (5.72 vs 6.14 kPa; P = 0.02) in the ketamine group compared with the thiopental group. Induction of anesthesia for cesarean section using ketamine is associated with a lower postoperative analgesic requirement compared with thiopental. IMPLICATIONS Patients who had anesthesia for cesarean section induced with ketamine required less analgesic drugs in the first 24 h compared with patients who received thiopental. Ketamine, unlike thiopental, has analgesic properties that may reduce sensitization of pain pathways and extend into the postoperative period.
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Affiliation(s)
- W D Ngan Kee
- Department of Anaesthesia and Intensive Care, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, N.T.
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Abstract
We have investigated the addition of adrenaline to epidural pethidine for postoperative analgesia in 40 patients after Caesarean section. In a randomised, double-blind study, patients received pethidine 25 mg with adrenaline 50 micrograms (adrenaline group, n = 20) or pethidine 25 mg without adrenaline (plain group, n = 18) epidurally at the first request for postoperative analgesia. The median duration of analgesia was longer in the adrenaline group (196 min; IQR 123-286) compared with the plain group (96 min; IQR 43-113; p = 0.002) and plasma concentrations of pethidine in the first 30 min after injection were lower in the adrenaline group (p = 0.003). Visual analogue scale pain scores in the first 30 min after injection and onset of analgesia, defined by the time for pain scores to decrease by 50%, were similar between groups. Addition of adrenaline to epidural pethidine has advantages for analgesia after Caesarean section.
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Affiliation(s)
- W D Ngan Kee
- Department of Anaesthesia and Intensive Care, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, People's Republic of China
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Abstract
PURPOSE To determine the effects of the addition of a background infusion to patient-controlled epidural analgesia (PCEA) using meperidine for analgesia after Caesarean section. METHODS In a randomized, double-blind study, we assigned 40 patients having elective Caesarean section to receive postoperative analgesia by patient-controlled epidural analgesia (PCEA) using meperidine 5 mg.ml-1 with (group Pi) or without (group Po) a background infusion of 10 mg.hr-l. The PCEA settings (20 mg bolus, 10 min lockout interval, four-hour maximum dose 150 mg) were otherwise identical. We compared pain at rest, pain on coughing, side effects, number of PCEA demands, drug consumption and patient satisfaction between groups in the first 24 hr after surgery. RESULTS Total consumption of meperidine was greater in group Pi (median 390 mg) than in group Po (median 240 mg; P = 0.017) and the number of PCEA demands was greater in group Po (median 12) than in group Pi (median 7.5; P = 0.012). Analgesia, side effects and patient satisfaction was similar between groups. CONCLUSION Addition of a background infusion to PCEA using meperidine after Caesarean section has no clinical benefit.
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Affiliation(s)
- W D Ngan Kee
- Department of Anaesthesia and Intensive Care, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong.
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Thorniley MS, Simpkin S, Barnett NJ, Wall P, Khaw KS, Shurey C, Sinclair JS, Green CJ. Applications of NIRS for measurements of tissue oxygenation and haemodynamics during surgery. Adv Exp Med Biol 1997; 411:481-93. [PMID: 9269465 DOI: 10.1007/978-1-4615-5865-1_61] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- M S Thorniley
- Department of Surgical Research, Northwick Park Institute for Medical Research, Northwick Park Hospital, Harrow, Middlesex, United Kingdom
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