Amplitude Analysis of the B^{0}→K^{*0}μ^{+}μ^{-} Decay

An amplitude analysis of the B^{0}→K^{*0}μ^{+}μ^{-} decay is presented using a dataset corresponding to an integrated luminosity of 4.7  fb^{-1} of pp collision data collected with the LHCb experiment. For the first time, the coefficients associated to short-distance physics effects, sensitive to processes beyond the standard model, are extracted directly from the data through a q^{2}-unbinned amplitude analysis, where q^{2} is the μ^{+}μ^{-} invariant mass squared. Long-distance contributions, which originate from nonfactorizable QCD processes, are systematically investigated, and the most accurate assessment to date of their impact on the physical observables is obtained. The pattern of measured corrections to the short-distance couplings is found to be consistent with previous analyses of b- to s-quark transitions, with the largest discrepancy from the standard model predictions found to be at the level of 1.8 standard deviations. The global significance of the observed differences in the decay is 1.4 standard deviations.

Fraction of χ_{c} Decays in Prompt J/ψ Production Measured in pPb Collisions at sqrt[s_{NN}]=8.16 TeV

The fraction of χ_{c1} and χ_{c2} decays in the prompt J/ψ yield, F_{χ_{c}→J/ψ}=σ_{χ_{c}→J/ψ}/σ_{J/ψ}, is measured by the LHCb detector in pPb collisions at sqrt[s_{NN}]=8.16  TeV. The study covers the forward (1.5 Collapse

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Observation of Cabibbo-Suppressed Two-Body Hadronic Decays and Precision Mass Measurement of the Ω_{c}^{0} Baryon

The first observation of the singly Cabibbo-suppressed Ω_{c}^{0}→Ω^{-}K^{+} and Ω_{c}^{0}→Ξ^{-}π^{+} decays is reported, using proton-proton collision data at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4  fb^{-1}, collected with the LHCb detector between 2016 and 2018. The branching fraction ratios are measured to be B(Ω_{c}^{0}→Ω^{-}K^{+})/B(Ω_{c}^{0}→Ω^{-}π^{+})=[6.08±0.51(stat)±0.40(syst)]%,B(Ω_{c}^{0}→Ξ^{-}π^{+})/B(Ω_{c}^{0}→Ω^{-}π^{+})=[15.81±0.87(stat)±0.44(syst)±0.16(ext)]%. In addition, using the Ω_{c}^{0}→Ω^{-}π^{+} decay channel, the Ω_{c}^{0} baryon mass is measured to be M(Ω_{c}^{0})=2695.28±0.07(stat)±0.27(syst)±0.30(ext)  MeV, improving the precision of the previous world average by a factor of 4.

Enhanced Production of Λ_{b}^{0} Baryons in High-Multiplicity pp Collisions at sqrt[s]=13 TeV

The production rate of Λ_{b}^{0} baryons relative to B^{0} mesons in pp collisions at a center-of-mass energy sqrt[s]=13  TeV is measured by the LHCb experiment. The ratio of Λ_{b}^{0} to B^{0} production cross sections shows a significant dependence on both the transverse momentum and the measured charged-particle multiplicity. At low multiplicity, the ratio measured at LHCb is consistent with the value measured in e^{+}e^{-} collisions, and increases by a factor of ∼2 with increasing multiplicity. At relatively low transverse momentum, the ratio of Λ_{b}^{0} to B^{0} cross sections is higher than what is measured in e^{+}e^{-} collisions, but converges with the e^{+}e^{-} ratio as the momentum increases. These results imply that the evolution of heavy b quarks into final-state hadrons is influenced by the density of the hadronic environment produced in the collision. Comparisons with several models and implications for the mechanisms enforcing quark confinement are discussed.

Improved Measurement of CP Violation Parameters in B_{s}^{0}→J/ψK^{+}K^{-} Decays in the Vicinity of the ϕ(1020) Resonance

The decay-time-dependent CP asymmetry in B_{s}^{0}→J/ψ(→μ^{+}μ^{-})K^{+}K^{-} decays is measured using proton-proton collision data, corresponding to an integrated luminosity of 6  fb^{-1}, collected with the LHCb detector at a center-of-mass energy of 13 TeV. Using a sample of approximately 349 000 B_{s}^{0} signal decays with an invariant K^{+}K^{-} mass in the vicinity of the ϕ(1020) resonance, the CP-violating phase ϕ_{s} is measured, along with the difference in decay widths of the light and heavy mass eigenstates of the B_{s}^{0}-B[over ¯]_{s}^{0} system, ΔΓ_{s}, and the difference of the average B_{s}^{0} and B^{0} meson decay widths, Γ_{s}-Γ_{d}. The values obtained are ϕ_{s}=-0.039±0.022±0.006  rad, ΔΓ_{s}=0.0845±0.0044±0.0024  ps^{-1}, and Γ_{s}-Γ_{d}=-0.0056_{-0.0015}^{+0.0013}±0.0014  ps^{-1}, where the first uncertainty is statistical and the second systematic. These are the most precise single measurements to date and are consistent with expectations based on the Standard Model and with the previous LHCb analyses of this decay. These results are combined with previous independent LHCb measurements. The phase ϕ_{s} is also measured independently for each polarization state of the K^{+}K^{-} system and shows no evidence for polarization dependence.

Measurement of CP Violation in B^{0}→ψ(→ℓ^{+}ℓ^{-})K_{S}^{0}(→π^{+}π^{-}) Decays

A measurement of time-dependent CP violation in the decays of B^{0} and B[over ¯]^{0} mesons to the final states J/ψ(→μ^{+}μ^{-})K_{S}^{0}, ψ(2S)(→μ^{+}μ^{-})K_{S}^{0} and J/ψ(→e^{+}e^{-})K_{S}^{0} with K_{S}^{0}→π^{+}π^{-} is presented. The data correspond to an integrated luminosity of 6  fb^{-1} collected at a center-of-mass energy of sqrt[s]=13  TeV with the LHCb detector. The CP-violation parameters are measured to be S_{ψK_{S}^{0}}=0.717±0.013(stat)±0.008(syst) and C_{ψK_{S}^{0}}=0.008±0.012(stat)±0.003(syst). This measurement of S_{ψK_{S}^{0}} represents the most precise single measurement of the CKM angle β to date and is more precise than the current world average. In addition, measurements of the CP-violation parameters of the individual channels are reported and a combination with the LHCb Run 1 measurements is performed.

Observation of New Baryons in the Ξ_{b}^{-}π^{+}π^{-} and Ξ_{b}^{0}π^{+}π^{-} Systems

The first observation and study of two new baryonic structures in the final state Ξ_{b}^{0}π^{+}π^{-} and the confirmation of the Ξ_{b}(6100)^{-} state in the Ξ_{b}^{-}π^{+}π^{-} decay mode are reported using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9  fb^{-1}. In addition, the properties of the known Ξ_{b}^{*0}, Ξ_{b}^{'-} and Ξ_{b}^{*-} resonances are measured with improved precision. The new decay mode of the Ξ_{b}^{0} baryon to the Ξ_{c}^{+} π^{-} π^{+} π^{-} final state is observed and exploited for the first time in these measurements.

Precision Measurement of CP Violation in the Penguin-Mediated Decay B_{s}^{0}→ϕϕ

A flavor-tagged time-dependent angular analysis of the decay B_{s}^{0}→ϕϕ is performed using pp collision data collected by the LHCb experiment at the center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6  fb^{-1}. The CP-violating phase and direct CP-violation parameter are measured to be ϕ_{s}^{ss[over ¯]s}=-0.042±0.075±0.009  rad and |λ|=1.004±0.030±0.009, respectively, assuming the same values for all polarization states of the ϕϕ system. In these results, the first uncertainties are statistical and the second systematic. These parameters are also determined separately for each polarization state, showing no evidence for polarization dependence. The results are combined with previous LHCb measurements using pp collisions at center-of-mass energies of 7 and 8 TeV, yielding ϕ_{s}^{ss[over ¯]s}=-0.074±0.069  rad and |λ|=1.009±0.030. This is the most precise study of time-dependent CP violation in a penguin-dominated B meson decay. The results are consistent with CP symmetry and with the standard model predictions.

Measurement of the Λ_{b}^{0}→Λ(1520)μ^{+}μ^{-} Differential Branching Fraction

The branching fraction of the rare decay Λ_{b}^{0}→Λ(1520)μ^{+}μ^{-} is measured for the first time, in the squared dimuon mass intervals q^{2}, excluding the J/ψ and ψ(2S) regions. The data sample analyzed was collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of 9  fb^{-1}. The result in the highest q^{2} interval, q^{2}>15.0  GeV^{2}/c^{4}, where theoretical predictions have the smallest model dependence, agrees with the predictions.

Observation of New Ω_{c}^{0} States Decaying to the Ξ_{c}^{+}K^{-} Final State

Two new excited states, Ω_{c}(3185)^{0} and Ω_{c}(3327)^{0}, are observed in the Ξ_{c}^{+}K^{-} invariant-mass spectrum using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9  fb^{-1}. Five previously observed excited Ω_{c}^{0} states are confirmed, namely Ω_{c}(3000)^{0}, Ω_{c}(3050)^{0}, Ω_{c}(3065)^{0}, Ω_{c}(3090)^{0}, and Ω_{c}(3119)^{0}. The masses and widths of these seven states are measured with the highest precision to date.

Evidence of a J/ψK_{S}^{0} Structure in B^{0}→J/ψϕK_{S}^{0} Decays

An amplitude analysis of B^{0}→J/ψϕK_{S}^{0} decays is performed using proton-proton collision data, corresponding to an integrated luminosity of 9  fb^{-1}, collected with the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV. Evidence with a significance of 4.0 standard deviations of a structure in the J/ψK_{S}^{0} system, named T_{ψs1}^{θ}(4000)^{0}, is seen, with its mass and width measured to be 3991_{-10}^{+12} _{-17}^{+9}  MeV/c^{2} and 105_{-25}^{+29} _{-23}^{+17}  MeV, respectively, where the first uncertainty is statistical and the second systematic. The T_{ψs1}^{θ}(4000)^{0} state is likely to be the isospin partner of the T_{ψs1}^{θ}(4000)^{+} state, previously observed in the J/ψK^{+} system of the B^{+}→J/ψϕK^{+} decay. When isospin symmetry for the charged and neutral T_{ψs1}^{θ}(4000) states is assumed, the signal significance increases to 5.4 standard deviations.

Measurement of the Ratios of Branching Fractions R(D^{*}) and R(D^{0})

The ratios of branching fractions R(D^{*})≡B(B[over ¯]→D^{*}τ^{-}ν[over ¯]_{τ})/B(B[over ¯]→D^{*}μ^{-}ν[over ¯]_{μ}) and R(D^{0})≡B(B^{-}→D^{0}τ^{-}ν[over ¯]_{τ})/B(B^{-}→D^{0}μ^{-}ν[over ¯]_{μ}) are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0  fb^{-1} of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode τ^{-}→μ^{-}ν_{τ}ν[over ¯]_{μ}. The measured values are R(D^{*})=0.281±0.018±0.024 and R(D^{0})=0.441±0.060±0.066, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is ρ=-0.43. The results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the standard model.

Measurement of the Time-Integrated CP Asymmetry in D^{0}→K^{-}K^{+} Decays

The time-integrated CP asymmetry in the Cabibbo-suppressed decay D^{0}→K^{-}K^{+} is measured using proton-proton collision data, corresponding to an integrated luminosity of 5.7  fb^{-1} collected at a center-of-mass energy of 13 TeV with the LHCb detector. The D^{0} mesons are required to originate from promptly produced D^{*+}→D^{0}π^{+} decays, and the charge of the companion pion is used to determine the flavor of the charm meson at production. The time-integrated CP asymmetry is measured to be A_{CP}(K^{-}K^{+})=[6.8±5.4±1.6]×10^{-4} where the first uncertainty is statistical and the second systematic. The direct CP asymmetries in D^{0}→K^{-}K^{+} and D^{0}→π^{-}π^{+} decays, a_{K^{-}K^{+}}^{d} and a_{π^{-}π^{+}}^{d}, are derived by combining A_{CP}(K^{-}K^{+}) with the time-integrated CP asymmetry difference, ΔA_{CP}=A_{CP}(K^{-}K^{+})-A_{CP}(π^{-}π^{+}), and other inputs, giving a_{K^{-}K^{+}}^{d}=(7.7±5.7)×10^{-4},a_{π^{-}π^{+}}^{d}=(23.2±6.1)×10^{-4},with a correlation coefficient corresponding to ρ=0.88. The compatibility of these results with CP symmetry is 1.4 and 3.8 standard deviations for D^{0}→K^{-}K^{+} and D^{0}→π^{-}π^{+} decays, respectively. This is the first evidence for direct CP violation in a specific D^{0} decay.

Lack of Association of Initial Vasopressor Dosing with Survival and Cardiac Re-Arrest Likelihood After Return of Spontaneous Circulation

BACKGROUND

Cardiac arrest occurs in approximately 350,000 patients outside the hospital and approximately 30,000 patients in the emergency department (ED) annually in the United States. When return of spontaneous circulation (ROSC) is achieved, hypotension is a common complication. However, optimal dosing of vasopressors is not clear.

OBJECTIVE

The objective of this study was to determine if initial vasopressor dosing was associated with cardiac re-arrest in patients after ROSC.

METHODS

This was a retrospective, single-center analysis of adult patients experiencing cardiac arrest prior to arrival or within the ED. Patients were assigned to one of four groups based on starting dose of vasopressor: low dose (LD; < 0.25 µg/kg/min), medium dose (MD; 0.25-0.49 µg/kg/min), high dose (HD; 0.5-0.99 µg/kg/min), and very high dose (VHD; ≥ 1 µg/kg/min). Data collection was performed primarily via manual chart review of medical records. The primary outcome was incidence of cardiac re-arrest within 1 h of vasopressor initiation. Multivariate logistic regression analysis was conducted to identify any covariates strongly associated with the primary outcome.

RESULTS

No difference in cardiac re-arrest incidence was noted between groups. The VHD group was significantly more likely to require a second vasopressor (p = 0.003). The HD group had lower survival rates to hospital discharge compared with the LD and MD groups (p = 0.0033 and p = 0.0147). In the multivariate regression, longer duration of pre-vasopressor re-arrests and hyperkalemic cardiac arrest etiology were significant predictors of cardiac re-arrest after vasopressor initiation.

CONCLUSIONS

Initial vasopressor dosing was not found to be associated with risk of cardiac re-arrest or, conversely, risk of adverse events.

Measurement of the Branching Fractions B(B^{0}→pp[over ¯]pp[over ¯]) and B(B_{s}^{0}→pp[over ¯]pp[over ¯])

Searches for the rare hadronic decays B^{0}→pp[over ¯]pp[over ¯] and B_{s}^{0}→pp[over ¯]pp[over ¯] are performed using proton-proton collision data recorded by the LHCb experiment and corresponding to an integrated luminosity of 9  fb^{-1}. Significances of 9.3σ and 4.0σ, including statistical and systematic uncertainties, are obtained for the B^{0}→pp[over ¯]pp[over ¯] and B_{s}^{0}→pp[over ¯]pp[over ¯] signals, respectively. The branching fractions are measured relative to the topologically similar normalization decays B^{0}→J/ψ(→pp[over ¯])K^{*0}(→K^{+}π^{-}) and B_{s}^{0}→J/ψ(→pp[over ¯])⁢ϕ(→K^{+}K^{-}). The branching fractions are measured to be B(B^{0}→pp[over ¯]pp[over ¯])=(2.2±0.4±0.1±0.1)×10^{-8} and B(B_{s}^{0}→pp[over ¯]pp[over ¯])=(2.3±1.0±0.2±0.1)×10^{-8}. In these measurements, the first uncertainty is statistical, the second is systematic, and the third one is due to the external branching fraction of the normalization channel.

Observation of a Resonant Structure near the D_{s}^{+}D_{s}^{-} Threshold in the B^{+}→D_{s}^{+}D_{s}^{-}K^{+} Decay

An amplitude analysis of the B^{+}→D_{s}^{+}D_{s}^{-}K^{+} decay is carried out to study for the first time its intermediate resonant contributions, using proton-proton collision data collected with the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV. A near-threshold peaking structure, referred to as X(3960), is observed in the D_{s}^{+}D_{s}^{-} invariant-mass spectrum with significance greater than 12 standard deviations. The mass, width, and the quantum numbers of the structure are measured to be 3956±5±10  MeV, 43±13±8  MeV, and J^{PC}=0^{++}, respectively, where the first uncertainties are statistical and the second systematic. The properties of the new structure are consistent with recent theoretical predictions for a state composed of cc[over ¯]ss[over ¯] quarks. Evidence for an additional structure is found around 4140 MeV in the D_{s}^{+}D_{s}^{-} invariant mass, which might be caused either by a new resonance with the 0^{++} assignment or by a J/ψϕ↔D_{s}^{+}D_{s}^{-} coupled-channel effect.

Test of Lepton Universality in b→sℓ^{+}ℓ^{-} Decays

The first simultaneous test of muon-electron universality using B^{+}→K^{+}ℓ^{+}ℓ^{-} and B^{0}→K^{*0}ℓ^{+}ℓ^{-} decays is performed, in two ranges of the dilepton invariant-mass squared, q^{2}. The analysis uses beauty mesons produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9  fb^{-1}. Each of the four lepton universality measurements reported is either the first in the given q^{2} interval or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model.

First Observation of a Doubly Charged Tetraquark and Its Neutral Partner

A combined amplitude analysis is performed for the decays B^{0}→D[over ¯]^{0}D_{s}^{+}π^{-} and B^{+}→D^{-}D_{s}^{+}π^{+}, which are related by isospin symmetry. The analysis is based on data collected by the LHCb detector in proton-proton collisions at center-of-mass energies of 7, 8, and 13 TeV. The full data sample corresponds to an integrated luminosity of 9  fb^{-1}. Two new resonant states with masses of 2.908±0.011±0.020  GeV and widths of 0.136±0.023±0.013  GeV are observed, which decay to D_{s}^{+}π^{+} and D_{s}^{+}π^{-} respectively. The former state indicates the first observation of a doubly charged open-charm tetraquark state with minimal quark content [cs[over ¯]ud[over ¯]], and the latter state is a neutral tetraquark composed of [cs[over ¯]u[over ¯]d] quarks. Both states are found to have spin-parity of 0^{+}, and their resonant parameters are consistent with each other, which suggests that they belong to an isospin triplet.

Search for Rare Decays of D^{0} Mesons into Two Muons

A search for the very rare D^{0}→μ^{+}μ^{-} decay is performed using data collected by the LHCb experiment in proton-proton collisions at sqrt[s]=7, 8, and 13 TeV, corresponding to an integrated luminosity of 9  fb^{-1}. The search is optimized for D^{0} mesons from D^{*+}→D^{0}π^{+} decays but is also sensitive to D^{0} mesons from other sources. No evidence for an excess of events over the expected background is observed. An upper limit on the branching fraction of this decay is set at B(D^{0}→μ^{+}μ^{-})<3.1×10^{-9} at a 90% C.L. This represents the world's most stringent limit, constraining models of physics beyond the standard model.

Observation of a J/ψΛ Resonance Consistent with a Strange Pentaquark Candidate in B^{-}→J/ψΛp[over ¯] Decays

An amplitude analysis of B^{-}→J/ψΛp[over ¯] decays is performed using 4400 signal candidates selected on a data sample of pp collisions recorded at center-of-mass energies of 7, 8, and 13 TeV with the LHCb detector, corresponding to an integrated luminosity of 9  fb^{-1}. A narrow resonance in the J/ψΛ system, consistent with a pentaquark candidate with strangeness, is observed with high significance. The mass and the width of this new state are measured to be 4338.2±0.7±0.4  MeV and 7.0±1.2±1.3  MeV, where the first uncertainty is statistical and the second systematic. The spin is determined to be 1/2 and negative parity is preferred. Because of the small Q-value of the reaction, the most precise single measurement of the B^{-} mass to date, 5279.44±0.05±0.07  MeV, is obtained.

Respiratory Responses to Two Voice Interventions for Parkinson's Disease

PURPOSE

The purpose of this study was to examine the respiratory strategies used by persons with Parkinson's disease (PD) to support louder speech in response to two voice interventions. Contrasting interventions were selected to investigate the role of internal and external cue strategies on treatment outcomes. LSVT LOUD, which uses an internal cueing framework, and the SpeechVive prosthesis, which employs an external noise cue to elicit louder speech, were studied.

METHOD

Thirty-four persons with hypophonia secondary to idiopathic PD were assigned to one of three groups: LSVT LOUD (n = 12), SpeechVive (n = 12), or a nontreatment clinical control (n = 10). The LSVT LOUD and SpeechVive participants received 8 weeks of voice intervention. Acoustic and respiratory kinematic data were simultaneously collected at pre-, mid- and posttreatment during a monologue speech sample. Intervention outcomes included sound pressure level (SPL), utterance length, lung volume initiation, lung volume termination, and lung volume excursion.

RESULTS

As compared to controls, the LSVT LOUD and SpeechVive participants significantly increased SPL at mid- and posttreatment, thus confirming a positive intervention effect. Treatment-related changes in speech breathing were further identified, including significantly longer utterance lengths (syllables per breath group) at mid- and posttreatment, as compared to pretreatment. The respiratory strategies used to support louder speech varied by group. The LSVT LOUD participants terminated lung volume at significantly lower levels at mid- and posttreatment, as compared to pretreatment. This finding suggests the use of greater expiratory muscle effort by the LSVT LOUD participants to support louder speech. Participants in the SpeechVive group did not significantly alter their respiratory strategies across the intervention period. Single-subject effect sizes highlight the variability in respiratory strategies used across speakers to support louder speech.

CONCLUSIONS

This study provides emerging evidence to suggest that the LSVT LOUD and SpeechVive therapies elicit different respiratory adjustments in persons with PD. The study highlights the need to consider respiratory function when addressing voice targets in persons with PD.

Perception of Physical Demand, Mental Demand, and Performance: A Comparison of Two Voice Interventions for Parkinson's Disease

PURPOSE

The purpose of the study was to examine the effect of two voice intervention approaches for hypophonia secondary to Parkinson's disease (PD) on self-reported measures of physical demand, mental demand, and vocal performance.

METHOD

Thirty-four persons with hypophonia secondary to PD were assigned to one of three groups: Lee Silverman Voice Treatment (LSVT) LOUD (n = 12), SpeechVive (n = 12), and nontreatment clinical control (n = 10). The LSVT LOUD and the SpeechVive participants received 8 weeks of voice intervention following the standardized protocol previously described for each approach. To confirm the effectiveness of each voice intervention, sound pressure level (dB SPL) data were analyzed for the experimental and control participants for a monologue sample obtained pretreatment, midtreatment, and posttreatment. During the voice intervention period, the LSVT LOUD and the SpeechVive participants were instructed to complete a modified version of the National Aeronautics and Space Administration Task Load Index rating scale to indicate the mental and physical demand required to complete the intervention activities, and to indicate how well they performed in completing the assigned vocal tasks.

RESULTS

The LSVT LOUD and the SpeechVive participants demonstrated a significant posttreatment increase in SPL (dB), in comparison to the clinical controls, thus confirming a positive intervention effect. The LSVT LOUD participants reported significantly higher ratings of physical and mental demand over the course of treatment, in comparison to the SpeechVive participants.

CONCLUSION

Consideration of the mental and physical demand associated with two voice intervention approaches, commonly used for PD, may help to foster improved therapeutic compliance and treatment outcomes.

A Comparison of Healthy and Disordered Voices Using Multi-Dimensional Voice Program, Praat, and TF32

PURPOSE

Instrumental voice assessment plays a critical role in identifying vocal issues and for documenting treatment outcomes. The reported voice data, however, are sensitive to the algorithm used by each acoustic analysis software program (AASP) to analyze the corresponding waveform. In the present study, five acoustic measures were compared across healthy speakers and speakers with dysphonia for three AASPs commonly used in research, education, and clinical practice: Multidimensional Voice Program (MDVP) by Computerized Speech Lab, Praat, and TF32.

MATERIALS AND METHODS

Sustained vowel phonations for the quantal vowels /ɑ/, /i/, and /u/ were analyzed for 80 speakers with organic dysphonia and 60 age- and sex-matched healthy controls. Descriptive, inferential, and correlation data are reported for mean fundamental frequency (mean F0), standard deviation of fundamental frequency (SD F0), short-term perturbation measures of jitter and shimmer, and harmonic-to-noise ratio (HNR).

RESULTS

The present study replicated previous findings of interprogram differences for healthy speakers, with MDVP consistently yielding higher values than Praat and TF32 for SD F0, jitter, and shimmer and lower values for HNR. Similar, but magnified patterns of results were observed for speakers with dysphonia.

CONCLUSION

The variation observed across programs calls into question the validity in comparing voice outcomes reported by one AASP to those previously obtained by another, particularly for acoustic signals with aperiodic components that are commonly present in disordered voices. It is advised that waveforms be visually inspected prior to conducting acoustic analysis, and that voice outcomes not be combined or compared across AASPs.

Transfer boarding delays care more in low-volume rural emergency departments: A cohort study

PURPOSE

Emergency department (ED) crowding is increasing and is associated with adverse patient outcomes. The objective of this study was to measure the relative impact of ED boarding on timeliness of early ED care for new patient arrivals, with a focus on the differential impact in low-volume rural hospitals.

METHODS

A retrospective cohort of all patients presenting to a Veterans Health Administration (VHA) ED between 2011 and 2014. The primary exposure was the number of patients in the ED at the time of ED registration, stratified by disposition (admit, discharge, or transfer) and mental health diagnosis. The primary outcome was time-to-provider evaluation, and secondary outcomes included time-to-EKG, time-to-laboratory testing, time-to-radiography, and total ED length-of-stay. Rurality was measured using the Rural-Urban Commuting Areas.

FINDINGS

A total of 5,912,368 patients were included from all 123 VHA EDs. Adjusting for acuity, new patients had longer time-to-provider when more patients were in the ED, and patients awaiting transfer for nonmental health conditions impacted time-to-provider for new patients (16.6 min delays, 95% CI: 12.3-20.7 min) more than other patient types. Rural patients saw a greater impact of crowding on care timeliness than nonrural patients (additional 5.3 min in time-to-provider per additional patient in ED, 95% CI: 4.3-6.4), and the impact of additional patients in all categories was most pronounced in the lowest-volume EDs.

CONCLUSIONS

Patients seen in EDs with more crowding have small, but additive, delays in early elements of ED care, and transferring patients with nonmental health diagnoses from rural facilities were associated with the greatest impact.

235. Outcomes Associated with Extended Oral Antibiotic Prophylaxis After 2-Stage Exchange Surgery to Prevent Recurrent Prosthetic Joint Infection

Background

2-stage exchange (2SE) surgery is often used to treat chronic prosthetic joint infections (PJI). IDSA guidelines do not recommend oral antibiotic suppression after 2SE. However, a recent randomized trial suggested that oral antibiotics for 3 months after arthroplasty reimplantation may prevent recurrent PJI. Objective: To compare rates of treatment failure (i.e., recurrent PJI) and adverse reactions (ARs) among patients who received < 1 month of antibiotics directly after reimplantation to those who received 1-3 months of antibiotics following reimplantation (extended antibiotics).

Methods

This retrospective cohort study included patients with hip, knee, or shoulder PJI who underwent 2SE at 83 VA hospitals between the years 2003-2017. PJI was defined using administrative codes and microbiology data. Patients were followed for 5 years to assess treatment failure (TF) and ARs. TF was defined as recurrent PJI, debridement, or reoperation. ARs included Clostridioides difficile infections (CDI), or antibiotic associated diarrhea (AAD) during or 72 hours after antibiotics. Chi-square tests were used to compare outcomes. Cumulative incidence function curves were created to compare TF rates between those who did and did not receive extended antibiotic treatment, incorporating the competing risks of TF and death.

Results

Of the 433 patients, most (97%) received < 1 month of oral antibiotics and 3% received extended antibiotics. The 15 patients who received extended antibiotics had similar rates of TF and ARs compared with patients who received < 1 month of oral antibiotics (Table). However, there was a trend toward higher rates of CDI (6.7% vs. 3.8%) and AAD (13.3% vs. 9.6%) among those who received extended antibiotics. There was no difference in TF comparing extended antibiotics with < 1 month of antibiotics, accounting for death (Figure).

Table: Treatment Failure and Adverse Reactions Among Those Who Did and Did Not Receive Extended Antibiotics

Conclusion

Few patients received extended oral antibiotics in the study period. There were no statistically significant differences in TF or ARs between the 2 groups. Yet, there was a trend toward higher rates of ARs among the extended antibiotic group. Future prospective studies should assess both the potential benefits and ARs associated with extended antibiotics among patients undergoing 2SE surgery.

Disclosures

Marin L. Schweizer, PhD, 3M (Grant/Research Support)PDI (Grant/Research Support) Bruce Alexander, PharmD, Bruce Alexander Consulting (Independent Contractor) Daniel Suh, MS MPH, General Electric (Shareholder)Merck (Shareholder)Moderna (Shareholder)Smile Direct Club (Shareholder) Aaron J. Tande, MD, UpToDate.com (Other Financial or Material Support, Honoraria for medical writing) Andrew Pugely, MD, MBA, Globus Medical (Research Grant or Support)Medtronic (Consultant)United Healthcare (Consultant)

92. Clinical Decision-Making about Chronic Antibiotic Suppression after Prosthetic Joint Infection Treatment: Qualitative Insights for Antibiotic Stewardship

Background

Patients who develop prosthetic joint infections (PJI) may be prescribed chronic antibiotic suppression (CAS) ( &gt; 6 months of antibiotics) after initial antibiotic treatment for the PJI. Patients at low risk of recurrent infection may be good targets for antibiotic stewardship. De-implementation of CAS could potentially reduce the emergence of antibiotic resistant organisms and decrease antibiotic-associated adverse events. Our ongoing study aims to characterize clinical decision-making processes about CAS prescribing and identify points for antibiotic stewardship interventions to stop CAS prescribing for patients who will not benefit.

Methods

We conducted semi-structured interviews with 33 physicians and nurses at 8 Veterans Affairs hospitals, chosen for variation in hospital size, complexity, region, and CAS prescribing. Interviewees included orthopedic surgeons, infectious disease (ID) physicians, hospital epidemiologists, nurses, nurse managers, and primary care physicians (PCPs). We conducted inductive, consensus-based thematic analysis on interview transcripts, using the program MAXQDA.

Results

Participants reported a complex decision-making process that included a range of collaborative approaches with other clinicians and patients. Their risk-benefit calculation for CAS usually included the type of revision surgery performed, the evidence base, the organism, and patient factors. Surgeons and ID physicians, the primary CAS prescribers, collaborated variably and sometimes consulted pharmacists or antibiotic stewards. Participants emphasized the importance of clinician autonomy and buy-in to order to effect practice change based on evidence, rather than top-down policies. They identified other significant time points that occurred before or after the CAS prescribing decision (initial PJI treatment decisions, follow-up appointments) and identified other decision makers about CAS maintenance (e.g., patients, PCPs). (See Figure 1).

Figure 1. Decision Points Relevant to Prescribing or Maintenance of Chronic Antibiotic Suppression after PJI. PJI, prosthetic joint infection; ID, Infectious Diseases physician; PCP, primary care physician; IV, intravenous

Conclusion

Interventions to optimize CAS prescribing should incorporate clinician concerns about prescriber autonomy and a preference for collaborative decision-making as well as understanding the range of decision makers across time.

Disclosures

Daniel Suh, MS MPH, General Electric (Shareholder)Merck (Shareholder)Moderna (Shareholder)Smile Direct Club (Shareholder) Bruce Alexander, PharmD, Bruce Alexander Consulting (Independent Contractor) Andrew Pugely, MD, MBA, Globus Medical (Research Grant or Support)Medtronic (Consultant)United Healthcare (Consultant) Marin Schweizer, PhD, 3M (Grant/Research Support)PDI (Grant/Research Support)

35. Acceptability of Proposed Stewardship Interventions to Reduce Preoperative Screening and Treatment of Asymptomatic Bacteriuria

Background

In 2019, the IDSA Clinical Practice guidelines on asymptomatic bacteriuria (ASB) recommended that clinicians no longer screen or treat patients for ASB before non-urological surgeries. However, it remains to be seen whether these guideline recommendations alone will produce changes in practice. Understanding clinical decision-making about preoperative urine screening and treatment can help design effective interventions to facilitate guideline concordance and support antibiotic stewardship. Our project objective was to qualitatively assess barriers and facilitators to reducing preoperative urine testing and treatment.

Methods

We conducted semi-structured interviews with 24 participants (surgeons, advance practice providers, pharmacists, infectious disease physicians, epidemiologists) at 4 Veterans Administration hospitals. We solicited feedback on 4 proposed interventions (substitution, lab restrictions, audit and feedback, interactive workshop), and invited suggestions on other interventions. Three researchers separately coded 20% of interview notes to sort responses to each intervention into acceptable, possibly acceptable, and not acceptable. The team then compared coding, resolved differences by consensus, and refined the code dictionary to ensure intercoder agreement; then each member coded one third of remaining notes.

Results

Participants expressed concerns about de-implementing routine urine testing and treatment for specific procedures and specialties (e.g., cardiothoracic). Some actively sought to identify and treat ASB. Participants found audit and feedback and substitution of different infection-control practices most acceptable. Participants suggested changes to make interventions more acceptable or feasible (e.g., tailoring to procedure, educational tailoring). Participants also identified new potential interventions (e.g. order set changes, collaborative decision making, education on potential harms, identification of testing costs).

Table 1. Acceptability of Proposed Interventions by Percentage of Participants. Percentages Do Not Add up to 100% Because Some Interviewees Did Not Answer Every Question.

Conclusion

Interventions to optimize urine screening and treatment for patients undergoing surgeries may require tailoring for surgical specialties, and should address clinical concerns about intervention feasibility.

Disclosures

Kalpana Gupta, MD, MPH, Abbott (Shareholder)DBC Pri-Med (Consultant)Glaxo Smith Kline (Consultant)Moderna (Shareholder)Nabriva Therapeutics (Consultant)Pfizer (Other Financial or Material Support, Grant to the institution)Qiagen (Consultant)Rebiotix (Consultant)Spero Therapeutics (Consultant)Utility Therapeutics (Consultant) Daniel Suh, MS MPH, General Electric (Shareholder)Merck (Shareholder)Moderna (Shareholder)Smile Direct Club (Shareholder) Bruce Alexander, PharmD, Bruce Alexander Consulting (Independent Contractor) Marin Schweizer, PhD, 3M (Grant/Research Support)PDI (Grant/Research Support)

Establishing the tolerability to broiler chickens and laying hens of nonanoic acid at practical levels of use as a feed flavouring

1. The following experiments were conducted to evaluate the effects of nonanoic acid (NA) in broilers and laying hens, at practical levels as a flavouring in complete feed.2. In the first experiment, 1100, one-day-old Ross 308 chicks, half male and female, were randomly assigned to 50 floor pens containing 22 chicks each. Chicks were fed one of five treatment diets containing either 0 (control), 100, 300, 500 or 1,000 mg NA/kg complete feed for 42 days.3. The NA treatment had no effect on ADFI, but there was a linear relationship with ADG and FCR. No differences were observed in blood parameters or tissue pathology among treatment groups.4. In a second study, 150 Hyline hens aged 24 weeks old were randomly assigned to 50 pens containing three birds each. Laying hens were fed one of five treatment diets containing 0 (control), 100, 300, 500 or 1,000 mg NA/kg complete feed for 56 days.5. Treatment with NA has no effect on live weight, ADFI or egg production in laying hens, and there were no observed changes in tissue pathology.6. The results supported the toleration of NA in broilers or layers at dietary levels of up to 1,000 mg/kg.

How Should We Organize Care for Patients With Human Immunodeficiency Virus and Comorbidities? A Multisite Qualitative Study of Human Immunodeficiency Virus Care in the United States Department of Veterans Affairs

BACKGROUND

With human immunodeficiency virus (HIV) now managed as a chronic disease, health care has had to change and expand to include management of other critical comorbidities. We sought to understand how variation in the organization, structure and processes of HIV and comorbidity care, based on patient-centered medical home (PCMH) principles, was related to care quality for Veterans with HIV.

RESEARCH DESIGN

Qualitative site visits were conducted at a purposive sample of 8 Department of Veterans Affairs Medical Centers, varying in care quality and outcomes for HIV and common comorbidities. Site visits entailed conduct of patient interviews (n=60); HIV care team interviews (n=60); direct observation of clinic processes and team interactions (n=22); and direct observations of patient-provider clinical encounters (n=45). Data were analyzed using a priori and emergent codes, construction of site syntheses and comparing sites with varying levels of quality.

RESULTS

Sites highest and lowest in both HIV and comorbidity care quality demonstrated clear differences in provision of PCMH-principled care. The highest site provided greater team-based, comprehensive, patient-centered, and data-driven care and engaged in continuous improvement. Sites with higher HIV care quality attended more to psychosocial needs. Sites that had consistent processes for comorbidity care, whether in HIV or primary care clinics, had higher quality of comorbidity care.

CONCLUSIONS

Provision of high-quality HIV care and high-quality co-morbidity care require different care structures and processes. Provision of both requires a focus on providing care aligned with PCMH principles, integrating psychosocial needs into care, and establishing explicit consistent approaches to comorbidity management.

Comparative Effectiveness of Switching to Daptomycin Versus Remaining on Vancomycin Among Patients With Methicillin-resistant Staphylococcus aureus (MRSA) Bloodstream Infections

BACKGROUND

Patients with methicillin-resistant Staphylococcus aureus bloodstream infections (MRSA BSI) usually receive initial treatment with vancomycin but may be switched to daptomycin for definitive therapy, especially if treatment failure is suspected. Our objective was to evaluate the effectiveness of switching from vancomycin to daptomycin compared with remaining on vancomycin among patients with MRSA BSI.

METHODS

Patients admitted to 124 Veterans Affairs Hospitals who experienced MRSA BSI and were treated with vancomycin during 2007-2014 were included. The association between switching to daptomycin and 30-day mortality was assessed using Cox regression models. Separate models were created for switching to daptomycin any time during the first hospitalization and for switching within 3 days of receiving vancomycin.

RESULTS

In total, 7411 patients received vancomycin for MRSA BSI. Also, 606 (8.2%) patients switched from vancomycin to daptomycin during the first hospitalization, and 108 (1.5%) switched from vancomycin to daptomycin within 3 days of starting vancomycin. In the multivariable analysis, switching to daptomycin within 3 days was significantly associated with lower 30-day mortality (hazards ratio [HR] = 0.48; 95% confidence interval [CI]: .25, .92). However, switching to daptomycin at any time during the first hospitalization was not significantly associated with 30-day mortality (HR: 0.87; 95% CI: .69, 1.09).

CONCLUSIONS

Switching to daptomycin within 3 days of initial receipt of vancomycin is associated with lower 30-day mortality among patients with MRSA BSI. This benefit was not seen when the switch occurred later. Future studies should prospectively assess the benefit of early switching from vancomycin to other anti-MRSA antibiotics.

An Improved Calibration Approach for Traveling Wave Ion Mobility Spectrometry: Robust, High-Precision Collision Cross Sections

The combination of ion-mobility (IM) separation with mass spectrometry (MS) has impacted global measurement efforts in areas ranging from food analysis to drug discovery. Reasons for the broad adoption of IM-MS include its significantly increased peak capacity, duty-cycle, and ability to reconstruct fragmentation data in parallel, all of which greatly enable the analyses of complex mixtures. More fundamentally, however, measurements of ion-gas molecule collision cross sections (CCSs) are used to support compound identification and quantitation efforts as well as study the structures of large biomolecules. As the first commercialized form of IM-MS, Traveling Wave Ion Mobility (TWIM) devices are operated at low pressures (∼3 mbar) and voltages, are relatively short (∼25 cm), and separate ions on a timescale of tens of milliseconds. These qualities make TWIM ideally suited for hybridization with MS. Owing to the complicated motion of ions in TWIM devices, however, IM transit times must be calibrated to enable CCS measurements. Applicability of these calibrations has hitherto been restricted to primarily singly charged small molecules and some classes of large, multiply charged ions under a significantly narrower range of instrument conditions. Here, we introduce and extensively characterize a dramatically improved TWIM calibration methodology. Using over 2500 experimental TWIM data sets, covering ions that span over 3.5 orders of magnitude of molecular mass, we demonstrate robust calibrations for a significantly expanded range of instrument conditions, thereby opening up new analytical application areas and enabling the expansion of high-precision CCS measurements for both existing and next-generation TWIM instrumentation.

The Effectiveness of Six Insulin Management Devices for Blind Diabetic Persons

Insulin measurement is a task all insulin dependent persons with diabetes must undertake one or more times daily. Diabetes is the leading cause of new blindness in the United States and as a result, there are many diabetics who have difficulty accomplishing safe, accurate insulin measurement independently. A variety of adaptive techniques and products are available to assist visually impaired persons with insulin measurement, but there are virtually no data available to support recommendation of any one device over another. A single-subject, alternating-treatment study was conducted with functionally blind diabetic persons to determine safety and accuracy of six leading commercial insulin measurement devices.

Lifetime History of Sexual Assault and Emergency Department Service Use among Women Veterans

BACKGROUND

Although sexual assault survivors are at increased risk for adverse physical and mental health outcomes and tend to use more health care services, little is known about women veterans' lifetime history of experiencing sexual assault (lifetime sexual assault [LSA]) and emergency department (ED) use. We sought to examine associations between experiencing LSA, mental health diagnoses, and ED use among women veterans.

METHODS

Computer-assisted telephone interviews were conducted with 980 women veterans enrolled at two Veterans Affairs (VA) Medical Centers to assess history of experiencing LSA, health care use, sociodemographic characteristics, and military history. Administrative data provided VA use, mental health, and medical diagnoses. Logistic regression analyses examined associations between experiencing LSA and mental health diagnoses and past 5-year ED use. Classification tree analysis characterized ED use in participant subgroups.

RESULTS

Sixty-four percent of participants visited a VA or non-VA ED during the previous 5 years. Women veterans with histories of mental health diagnoses and who experienced sexual assault had an odds of ED use almost two times greater than those with no history of experiencing sexual assault and no mental health diagnoses. The odds were similar for experiencing attempted (adjusted odds ratio, 1.85) and completed (adjusted odds ratio, 1.95) sexual assault. Classification tree analysis identified reliance on VA care and the composite variable representing experiencing LSA and mental health diagnoses as factors that best discriminated ED users from nonusers.

CONCLUSIONS

Experiencing LSA is associated with greater ED use in women veterans enrolled in the VA. Whether finding this reflects greater emergent health care needs, suboptimal access and treatment for conditions that could be managed in other settings, lack of health care coordination, or some combination of these factors is unclear.