Epidemiology and treatment of invasive Bartonella spp. infections in the United States.

OBJECTIVES: Bartonella spp., renowned for cat-scratch disease, has limited reports of dissemination. Tissue and blood cultures have limitations in detecting this fastidious pathogen. Molecular testing (polymerase chain reaction, PCR) and cell-free DNA have provided an avenue for diagnoses. This retrospective observational multicenter study describes the incidence of disseminated Bartonella spp. and treatment-related outcomes. METHODS: Inclusion criteria were diagnosis of bartonellosis via diagnosis code, serology testing of blood, polymerase chain reaction (PCR) of blood, 16/18S tests of blood or tissue, cultures of blood or tissue, or cell-free DNA of blood or tissue from January 1, 2014, through September 1, 2021. Exclusions were patients who did not receive treatment, insufficient data on treatment course, absence of dissemination, or retinitis as dissemination. RESULTS: Patients were primarily male (n = 25, 61.0%), white (n = 28, 68.3%), with mean age of 50 years (SD 14.4), and mean Charlson comorbidity index of 3.5 (SD 2.1). Diagnosis was primarily by serology (n = 34, 82.9%), with Bartonella henselae (n = 40, 97.6%) as the causative pathogen. Treatment was principally doxycycline with rifampin (n = 17, 41.5%). Treatment failure occurred in 16 (39.0%) patients, due to escalation of therapy during treatment (n = 5, 31.3%) or discontinuation of therapy due to an adverse event or tolerability (n = 5, 31.3%). CONCLUSIONS: In conclusion, this is the largest United States-based cohort of disseminated Bartonella spp. infections to date with a reported 39% treatment failure. This adds to literature supporting obtaining multiple diagnostic tests when Bartonella is suspected and describes treatment options.

Agreement Between Two-Concentration and One-Concentration Area Under the Curve (AUC) Estimates When Using Bayesian Modeling to Dose Vancomycin in Patients With Obesity.

BACKGROUND: Vancomycin Bayesian modeling provides 24-hour area under the curve (AUC24) estimations. However, the agreement between two-concentration and one-concentration Bayesian estimates in patients with obesity is unknown. OBJECTIVE: The purpose of this study was to determine the agreement between two-concentration and one-concentration Bayesian AUC24 estimates in patients with obesity receiving vancomycin. METHODS: This retrospective within-subjects cohort study included patients with obesity and two vancomycin concentrations. The first concentration was hidden from dosing software to record the one-concentration AUC24. AUC24 estimates were categorized into 1 of 3 groups: <400, 400 to 600, or >600 mg*h/L. Patients were excluded for vancomycin duration less than 48 hours or renal dysfunction. The primary outcome was AUC24 agreement with two versus one concentration. Secondary outcomes included the AUC24 category, matching of AUC24 categorization, and correlation between two-concentration versus one-concentration AUC24. AUC24 estimate agreement was assessed by Bland Altman plot and bias via linear regression. Statistical analyses were performed using SPSS (version 20.0). RESULTS: A total of 31 patients were included. The mean difference in AUC24 between two versus one concentration was 11.4 mg*h/L (95% limits of agreement = -72 to 95 mg*h/L). Linear regression indicated the presence of proportional bias at higher AUC24 values (ß = 0.16; P = 0.015). Matching of AUC24 categorization with two versus one concentration was 87% (27/31 patients). CONCLUSION AND RELEVANCE: This study demonstrated overall agreement between AUC24 estimates when using two versus one vancomycin concentration in patients with obesity, though proportional bias was detected at higher AUC24. Future studies with larger sample sizes are needed to confirm these results.

STIM1 clusters and activates CRAC channels via direct binding of a cytosolic domain to Orai1.

Store-operated Ca(2+) channels activated by the depletion of Ca(2+) from the endoplasmic reticulum (ER) are a major Ca(2+) entry pathway in nonexcitable cells and are essential for T cell activation and adaptive immunity. After store depletion, the ER Ca(2+) sensor STIM1 and the CRAC channel protein Orai1 redistribute to ER-plasma membrane (PM) junctions, but the fundamental issue of how STIM1 activates the CRAC channel at these sites is unresolved. Here, we identify a minimal, highly conserved 107-aa CRAC activation domain (CAD) of STIM1 that binds directly to the N and C termini of Orai1 to open the CRAC channel. Purified CAD forms a tetramer that clusters CRAC channels, but analysis of STIM1 mutants reveals that channel clustering is not sufficient for channel activation. These studies establish a molecular mechanism for store-operated Ca(2+) entry in which the direct binding of STIM1 to Orai1 drives the accumulation and the activation of CRAC channels at ER-PM junctions.

Perceptions on and roadblocks to implementation of standardized nomenclature in radiation oncology: A survey from TG-263U1.

PURPOSE: AAPM Task Group No. 263U1 (Update to Report No. 263 - Standardizing Nomenclatures in Radiation Oncology) disseminated a survey to receive feedback on utilization, gaps, and means to facilitate further adoption. METHODS: The survey was created by TG-263U1 members to solicit feedback from physicists, dosimetrists, and physicians working in radiation oncology. Questions on the adoption of the TG-263 standard were coupled with demographic information, such as clinical role, place of primary employment (e.g., private hospital, academic center), and size of institution. The survey was emailed to all AAPM, AAMD, and ASTRO members. RESULTS: The survey received 463 responses with 310 completed survey responses used for analysis, of whom most had the clinical role of medical physicist (73%) and the majority were from the United States (83%). There were 83% of respondents who indicated that they believe that having a nomenclature standard is important or very important and 61% had adopted all or portions of TG-263 in their clinics. For those yet to adopt TG-263, the staffing and implementation efforts were the main cause for delaying adoption. Fewer respondents had trouble adopting TG-263 for organs at risk (29%) versus target (44%) nomenclature. Common themes in written feedback were lack of physician support and available resources, especially in vendor systems, to facilitate adoption. CONCLUSIONS: While there is strong support and belief in the benefit of standardized nomenclature, the widespread adoption of TG-263 has been hindered by the effort needed by staff for implementation.  Feedback from the survey is being utilized to drive the focus of the update efforts and create tools to facilitate easier adoption of TG-263.

Unlocking the future of patient Education: ChatGPT vs. LexiComp® as sources of patient education materials.

BACKGROUND: ChatGPT is a conversational artificial intelligence technology that has shown application in various facets of healthcare. With the increased use of AI, it is imperative to assess the accuracy and comprehensibility of AI platforms. OBJECTIVE: This pilot project aimed to assess the understandability, readability, and accuracy of ChatGPT as a source of medication-related patient education as compared with an evidence-based medicine tertiary reference resource, LexiComp®. METHODS: Patient education materials (PEMs) were obtained from ChatGPT and LexiComp® for 8 common medications (albuterol, apixaban, atorvastatin, hydrocodone/acetaminophen, insulin glargine, levofloxacin, omeprazole, and sacubitril/valsartan). PEMs were extracted, blinded, and assessed by 2 investigators independently. The primary outcome was a comparison of the Patient Education Materials Assessment Tool-printable (PEMAT-P). Secondary outcomes included Flesch reading ease, Flesch Kincaid grade level, percent passive sentences, word count, and accuracy. A 7-item accuracy checklist for each medication was generated by expert consensus among pharmacist investigators, with LexiComp® PEMs serving as the control. PEMAT-P interrater reliability was determined via intraclass correlation coefficient (ICC). Flesch reading ease, Flesch Kincaid grade level, percent passive sentences, and word count were calculated by Microsoft® Word®. Continuous data were assessed using the Student's t-test via SPSS (version 20.0). RESULTS: No difference was found in the PEMAT-P understandability score of PEMs produced by ChatGPT versus LexiComp® [77.9% (11.0) vs. 72.5% (2.4), P=0.193]. Reading level was higher with ChatGPT [8.6 (1.2) vs. 5.6 (0.3), P < 0.001). ChatGPT PEMs had a lower percentage of passive sentences and lower word count. The average accuracy score of ChatGPT PEMs was 4.25/7 (61%), with scores ranging from 29% to 86%. CONCLUSION: Despite comparable PEMAT-P scores, ChatGPT PEMs did not meet grade level targets. Lower word count and passive text with ChatGPT PEMs could benefit patients, but the variable accuracy scores prevent routine use of ChatGPT to produce medication-related PEMs at this time.

Evaluation and correlation of patient movement during online adaptive radiotherapy with CBCT and a surface imaging system.

PURPOSE: With the clinical implementation of kV-CBCT-based daily online-adaptive radiotherapy, the ability to monitor, quantify, and correct patient movement during adaptive sessions is paramount. With sessions lasting between 20-45 min, the ability to detect and correct for small movements without restarting the entire session is critical to the adaptive workflow and dosimetric outcome. The purpose of this study was to quantify and evaluate the correlation of observed patient movement with machine logs and a surface imaging (SI) system during adaptive radiation therapy. METHODS: Treatment machine logs and SGRT registration data log files for 1972 individual sessions were exported and analyzed. For each session, the calculated shifts from a pre-delivery position verification CBCT were extracted from the machine logs and compared to the SGRT registration data log files captured during motion monitoring. The SGRT calculated shifts were compared to the reported shifts of the machine logs for comparison for all patients and eight disease site categories. RESULTS: The average (±STD) net displacement of the SGRT shifts were 2.6 ± 3.4 mm, 2.6 ± 3.5 mm, and 3.0 ± 3.2 in the lateral, longitudinal, and vertical directions, respectively. For the treatment machine logs, the average net displacements in the lateral, longitudinal, and vertical directions were 2.7 ± 3.7 mm, 2.6 ± 3.7 mm, and 3.2 ± 3.6 mm. The average difference (Machine-SGRT) was -0.1 ± 1.8 mm, 0.2 ± 2.1 mm, and -0.5 ± 2.5 mm for the lateral, longitudinal, and vertical directions. On average, a movement of 5.8 ± 5.6 mm and 5.3 ± 4.9 mm was calculated prior to delivery for the CBCT and SGRT systems, respectively. The Pearson correlation coefficient between CBCT and SGRT shifts was r = 0.88. The mean and median difference between the treatment machine logs and SGRT log files was less than 1 mm for all sites. CONCLUSION: Surface imaging should be used to monitor and quantify patient movement during adaptive radiotherapy.

Commissioning and clinical evaluation of the IDENTIFYTM surface imaging system for frameless stereotactic radiosurgery.

PURPOSE: To commission and assess the clinical performance of a new commercial surface imaging (SI) system by analyzing intra-fraction motion from the initial cohort of patients treated with frameless stereotactic radiosurgery (fSRS). METHODS: The IDENTIFYTM SI system was commissioned for clinical use on an Edge (Varian Medical Systems, Palo Alto, CA) linear accelerator. All patients who received intracranial radiotherapy with HyperArcTM (Varian Medical Systems, Palo Alto, CA) were immobilized with the EncompassTM (Qfix, Avondale, PA) thermoplastic mask and monitored for intra-fraction motion with SI. IDENTIFYTM log files were correlated with trajectory log files to correlate treatment parameters with SI-reported offsets. IDENTIFYTM reported offsets were correlated with gantry and couch angles to assess system performance for obstructed and clear camera field of view. Data were stratified by race to evaluate performance differences due to skin tone. RESULTS: All commissioning data were found to meet recommended tolerances. IDENTIFYTM was used to monitor intra-fraction motion on 1164 fractions from 386 patients. The median magnitude of translational SI reported offsets at the end of treatment was 0.27 mm. SI reported offsets were shown to increase when camera pods are blocked by the gantry with larger increases seen at non-zero couch angles. With camera obstruction, the median magnitude of the SI reported offset was 0.50 and 0.80 mm for White and Black patients, respectively. CONCLUSIONS: IDENTIFYTM performance during fSRS is comparable to other commercially available SI systems where offsets are shown to increase at non-zero couch angles and during camera pod blockage.

Acute Kidney Injury Incidence With Bayesian Dosing Software Versus 2-Level First-Order Area Under the Curve-Based Dosing of Vancomycin With Piperacillin-Tazobactam.

Background: Two methods of area under the curve (AUC) dosing are recommended in vancomycin consensus guidelines: first-order calculations utilizing 2 vancomycin concentrations or a Bayesian approach. It is unknown if there is a difference in acute kidney injury (AKI) between the 2 dosing strategies for patients receiving concomitant piperacillin-tazobactam and vancomycin (VPT). Objective: The objective of this study was to compare incidence of AKI in patients being administered VPT with first-order calculations versus model-informed precision dosing (MIPD)/Bayesian dosing. Methods: This was a single-center, retrospective, observational study at a community hospital. Patients who received VPT therapy for at least 48 hours were included. The primary outcome was overall incidence of AKI. Secondary outcomes included percentage target attainment with initial regimen, average serum creatinine increase, time to AKI, usable vancomycin levels, and need for temporary dialysis or intensive care unit admission. Results: There were 100 patients included (50 in the first-order group and 50 in the MIPD/Bayesian group). The overall incidence of AKI was lower in the MIPD/Bayesian group (12% vs 28%, P = 0.046). There was no difference in average serum creatinine increase, time to AKI, need for temporary dialysis, or intensive care unit admission. Patients in the MIPD/Bayesian group had a higher percentage of target attainment (46% vs 18%, P = 0.003) and usable vancomycin levels (98% vs 60%, P < 0.001). Conclusion and Relevance: In patients receiving VPT, model-informed precision dosing with Bayesian modeling resulted in a lower rate of AKI, higher target attainment, and more usable vancomycin levels compared with first-order AUC dosing. The small sample and retrospective nature of this study reinforces the need for additional data.

Analysis of a surface imaging system using a six degree-of-freedom couch.

PURPOSE: To validate surface imaging (SI)-reported offsets using a six degree-of-freedom couch and an anthropomorphic phantom for commissioning and routine quality assurance of an SI system used for stereotactic radiosurgery (SRS). METHODS: An anthropomorphic phantom with a radiopaque ball bearing (BB) placed either anterior, midline, or posterior, was tracked with SI with a typical SRS region of interest. Couch motion in all six degrees of freedom was programmed and delivered on a linac. SI system logs were synchronized with linac trajectory logs. Ten random couch positions were selected at couch 0°, 45°, 90°, 270°, 315° with megavolt (MV) images taken to account for couch walkout. The SI residual error (ε), the difference between SI reported offset and MV or trajectory log position, was calculated. Residual errors were measured with and without one SI pod blocked. RESULTS: The median [range] of magnitude of translational ε was 0.13 [0.07, 0.21], 0.16 [0.11, 0.26], 0.61 [0.50, 0.68], 0.49 [0.42, 0.55], 0.55 [0.38, 0.72] mm for couch rotations of 0°, 45°, 90°, 270°, 315°, respectively, for the midline BB and no pod blocked. The range of all translational ε from all couch angles (with and without pod block) at different BB positions is [0.05, 0.96] mm. The absolute range of difference when changing BB position when no pod is blocked in median translational ε is [0.01, 0.40] mm with the maximum at BB posterior. The absolute range of difference when not changing BB positions with and without pod block in median translational ε is [0.01, 0.37] mm with the maximum at BB posterior and couch 315°. CONCLUSION: SI system and linac trajectory log analysis can be used to assess SI system performance with automated couch motion to validate SI accuracy.

Rethinking residency recruitment, application, and interview processes to benefit applicants and programs long-term.

Pharmacy residency recruitment and interviews have been significantly impacted by the COVID-19 pandemic. Many traditional recruitment events and interviews were transitioned from in-person to virtual, and new approaches to recruitment, such as virtual open houses, were developed. There are limited data on how these changes impacted pharmacy residency applicants and programs, and the future of virtual events is currently unknown. We highlight recommendations for virtual recruitment and interviews and provide suggestions for residency programs and national organizations to improve virtual processes in the future.

Analysis of SGLT2 Inhibitor Therapy and Other Potential Risk Factors for the Development of Bacteremia in Patients With Urosepsis.

Background: Risk factors for the development of bacteremia in patients with urosepsis are not well-defined in the current literature. Objective: To assess potential risk factors, including receipt of SGLT2 inhibitor therapy (SGLT2-I), for the development of bacteremia in patients with urosepsis. Methods: A retrospective case control study was performed on patients admitted to a community hospital. Patients were included if they had a positive urine culture and met criteria for urosepsis. Exclusion criteria included proven source of infection outside of the urogenital tract, age less than or equal to 18 years old, and pregnancy. Included patients were placed into 1 of 2 groups: bacteremia or non-bacteremia. The primary endpoint was the percentage of patients taking an SGLT2-I in the bacteremia versus the non-bacteremia group. Secondary endpoints included an assessment of potential risk factors for the development of bacteremia in patients with urosepsis via univariate and multivariate regression analysis and comparison of clinical outcomes in patients receiving SGLT2-I prior to admission versus those not receiving SGLT2-I. Results: There was no difference in the proportion of patients within the bacteremia and non-bacteremia groups who were receiving an SGLT2-I (12% vs. 19%, P = 0.277). Binary multivariate regression analysis identified 2 variables associated with increased risk of bacteremia: male gender and cirrhosis. Conclusion: Within this study, there was no difference in the proportion of patients receiving an SGLT2-I in bacteremia and non-bacteremia groups. Potential risk factors for the development of bacteremia identified included male gender and cirrhosis. However, results from our study should be confirmed in larger scale studies.

Evaluating the Safety of Trough Versus Area Under the Curve (AUC)-Based Dosing Method of Vancomycin With Concomitant Piperacillin-Tazobactam.

Background: Vancomycin and piperacillin-tazobactam (VPT) is a common antibiotic combination used in hospitals, and there has been increasing data indicating that the combination is associated with increased rates of acute kidney injury (AKI). It is unclear if the dosing method of vancomycin would mitigate the risk of AKI seen with VPT. Objective: To observe and compare incidence of AKI in patients on VPT when using the trough-based dosing method versus the area-under-the-curve (AUC)-based dosing method. Methods: This was a multi-center, retrospective, observational study at 3 community hospitals. Adults receiving at least 48 hours of VPT were included. Patients with severe renal dysfunction, pregnant patients, prisoners, and patients with central nervous system infections, or malignancy were excluded. The primary outcome was incidence of AKI as defined by the Infectious Disease Society of America (IDSA) criteria. Results: A total of 300 patients were included in the study; 150 patients in both the trough and AUC groups. A total of 23 patients (15%) in the trough group and 17 patients (11%) in the AUC group met the primary outcome (odds ratio [OR]: 0.7058, 95% confidence interval [CI]: [0.3603, 1.3826], P = .3098). Conclusion and Relevance: The incidence of AKI was lower in the AUC group compared with the trough group; however, this was not significant. The results of our study suggest that there is no difference between incidence of AKI when using trough- or AUC-based dosing in those receiving VPT. Because of the small sample size and retrospective nature of the study, more data are needed.

A Continuing Education Activity Durably Addressed Knowledge Gaps Related to Penicillin Allergies Among Pharmacists and Pharmacy Technicians.

Background: Penicillin allergy is one of the most frequent self-reported allergies; however, only about 10% of reported allergies are accurate. Objectives: Through the creation of a continuing pharmacy education (CPE) activity, we sought to assess knowledge gaps and comfort levels in the management of penicillin allergies. Methods: A 1-hour enduring-content CPE activity was offered as an interactive course from September 20, 2019, to September 20, 2020. Participants completed 3 surveys (pre-survey, post-survey, and follow-up survey). Participants were pharmacists and pharmacy technicians who completed, at a minimum, the activity and both pre- and post-surveys. The primary outcome was the percentage of participants scoring >80% on knowledge-based questions on the post-survey compared with the pre-survey. Secondary outcomes included pre-post comparisons on knowledge-based questions, participants' self-report of an allergy, and comfort levels dispensing cephalosporins in a patient with a self-reported penicillin allergy. Results: A total of 389 participants completed the CPE activity, with 176 included for analysis. Significantly more participants scored >80% on knowledge-based questions on the post-survey compared with the pre-survey (71.6% vs 22.7%, P < .001). There was no significant difference between the percentage of participants scoring >80% on the post-survey and the follow-up survey (71.6% vs 65%, P = .119). The majority of participants (74%) felt comfortable dispensing a cephalosporin in a patient with a penicillin allergy on the pre-survey, with similar percentages on the post- and follow-up surveys (77% and 90%, respectively). Conclusion: A targeted continuing education program improved overall knowledge, which was sustained for up to 2 months.

Code Wisely: Risk assessment and mitigation for custom clinical software.

PURPOSE: The task of software development has become an increasing part of the medical physicist's role. Many physicists who are untrained in the best practices of software development have begun creating scripts for clinical use. There is an increasing need for guidance for both developers and medical physicists to code wisely in the clinic. MATERIALS AND METHODS: We created a novel model for assessing risk for custom clinical software analogous to failure modes and effects analysis and propose minimum best practices that should be followed to mitigate the risks. Using this risk model, we integrated a literature review and institutional experience to form a practical guide for risk mitigation. RESULTS: Using this new risk assessment model, we outlined several risk mitigation techniques including unit testing, code review, source control, end-user testing, and commissioning from the literature while sharing our institutional guidelines for evaluating software for risk and implementing these strategies. CONCLUSION: We found very little literature for custom software development guidelines targeted at medical physicists. We have shared our institutional experience and guidelines to help facilitate safe software development for the evolving role of the medical physicist.

Evaluation of a two-dimensional diode array for patient-specific quality assurance of HyperArc.

PURPOSE: To evaluate a two-dimensional diode array for patient-specific quality assurance of VMAT stereotactic radiosurgery (SRS) plans. METHODS: The diode array, an SRS MapCHECK (SRSMC), was composed of a 77 mm ×77 mm face-centered array having a spacing of 2.47 mm. Sixty SRS plans were selected from our clinical database, 30 for treatment of a single target and 30 for multiple targets. The target sizes ranged from 2.4 mm to 44.7 mm equivalent diameter (median 8.7 mm). The plans were delivered to the diode array. For multiple target plans, two measurements were obtained at two locations, one corresponding to the largest target and the other to the smallest target. Gamma using a 3%/1 mm criteria and the dose to the center diode were compared with radiochromic film (RCF). Dose to selected regions of the detector electronics was calculated. RESULTS: The mean difference between the center diode and RCF was -1.2%. For a threshold of at least 95% of detectors/pixels having gamma < 1 for a 3%/1 mm criteria, SRSMC and RCF gave consistent results for 79 of the 90 measurements. For plans with an arc having a patient support angle of 90° or 270°, the median dose to the electronics was 0.65% of the prescription dose. CONCLUSIONS: SRSMC is an efficient tool for accurate patient-specific quality assurance of VMAT single and multiple target radiosurgery, yielding similar clinical decisions as radiochromic film.

Safety and Efficacy of Apixaban Following Bioprosthetic Valve Replacements: A Retrospective Evaluation.

Background: Data on the use of direct oral anticoagulants in the setting of bioprosthetic valve replacements is limited. Objective: The purpose of this study was to describe outcomes among patients who underwent a bioprosthetic valve replacement and were subsequently prescribed apixaban. Methods: A retrospective cohort study was completed for inpatients at a community hospital who were prescribed apixaban following a bioprosthetic valve replacement from 2015 to 2020. Endpoints assessed included incidence of all-cause readmission and emergency visits within 3 months following valvular surgery, incidence of mortality, and all-cause major and minor bleeding. A post hoc analysis was conducted comparing outcomes among patients who underwent mitral versus aortic valve replacement, as well as patients with and without atrial fibrillation. The study was deemed exempt by hospital and university institutional review boards. Results: A total of 54 patients were included for analysis. All-cause readmission or emergency visit occurred in 33% (n = 18) of patients and the mortality rate was 6% (n = 3). A minor bleeding event was reported in 6% (n = 3) of patients and a major bleeding event was reported in 2% (n = 1) of patients. A thrombotic event was reported in 2% (n = 1) of patients. Conclusion: Within this cohort of patients requiring anticoagulation following bioprosthetic valve replacement, apixaban was safe and well-tolerated. However, more prospective data are needed to further correlate the safety and efficacy of apixaban, particularly in the setting of mitral valve replacement.

Incidence and Risk Factors of Acute Kidney Injury in Patients Receiving Concomitant Vancomycin and Continuous-Infusion Piperacillin/Tazobactam: A Retrospective Cohort Study.

BACKGROUND: During a recent shortage of small-volume parenteral solutions, some hospitals administered piperacillin/tazobactam via continuous infusion to utilize larger fluid volumes. Although the incidence of acute kidney injury (AKI) is well documented for patients receiving intermittent or extended-infusion piperacillin/tazobactam with concomitant vancomycin, no literature exists documenting the incidence of AKI in patients receiving continuous-infusion piperacillin/tazobactam. OBJECTIVE: The objective of this study is to examine the incidence and predictors of AKI in patients who received continuous-infusion piperacillin/tazobactam with concomitant intermittent-infusion vancomycin (VPT-CI) at a community hospital. METHODS: A retrospective cohort study was performed on patients who received VPT-CI between December 2017 and March 2018. Patients were eligible for inclusion if they were at least 19 years of age and received at least 48 hours of combination therapy. The primary outcome was incidence of AKI. The secondary outcome was an assessment of patient and treatment characteristics to determine predictors of AKI. RESULTS: A total of 120 patients were included in the study. The incidence of AKI in patients who received VPT-CI was 31.7%. Based on binary logistic regression analysis, risk factors associated with increased risk of AKI included admission to the intensive care unit and baseline creatinine clearance less than 60 mL/min. CONCLUSION AND RELEVANCE: The incidence of AKI for VPT-CI found in this study was comparable to that found with intermittent and extended-infusion piperacillin/tazobactam with concomitant vancomycin in prior literature. Additional research should further analyze risk factors for the development of AKI for patients on concomitant vancomycin and piperacillin/tazobactam therapy.

Technical Note: Use of automation to eliminate shift errors.

PURPOSE: To create automated tools within the treatment planning system (TPS) that eliminate the common error pathway of providing incorrect shift instructions to therapists. MATERIALS/METHODS: Two scripts were created within the TPS using the Eclipse API (Varian Medical Systems, Palo Alto, CA). One script detects whether or not the user origin has been placed correctly at the intersection of the simulation markers while the other calculates a shift instruction sheet that can be printed for treatment. RESULTS: Analysis of our RO-ILS database identified eight errors caused by improper setting of the user origin in the treatment planning system. The user origin script flagged all of the treatment plans for markers inconsistent with user origin. Automated calculation of shifts eliminated the error pathway of miscalculating or transcribing shift values. CONCLUSION: Automation can eliminate the common error pathway of providing the wrong shifts to therapists. The scripts have been made available as open-source software for implementation at other radiotherapy clinics.

Surface guided imaging during stereotactic radiosurgery with automated delivery.

PURPOSE: To report on the use of surface guided imaging during frameless intracranial stereotactic radiotherapy with automated delivery via HyperArcTM (Varian Medical Systems, Palo Alto, CA). METHODS: All patients received intracranial radiotherapy with HyperArcTM and were monitored for intrafraction motion by the AlignRT® (VisionRT, London, UK) surface imaging (SI) system. Immobilization was with the EncompassTM (Qfix, Avondale, PA) aquaplast mask device. AlignRT® log files were correlated with trajectory log files to correlate treatment parameters with SI reported offsets. SI reported offsets were correlated with gantry angle and analyzed for performance issues at non-zero couch angles and during camera-pod blockage during gantry motion. Demographics in the treatment management system were used to identify race and determine if differences in SI reported offsets are due to skin tone settings. RESULTS: A total of 981 fractions were monitored over 14 months and 819 were analyzed. The median AlignRT® reported motion from beginning to the end of treatment was 0.24 mm. The median offset before beam on at non-zero couch angles was 0.55 mm. During gantry motion when camera pods are blocked, the median magnitude was below 1 mm. Median magnitude of offsets at non-zero couch angles was not found to be significantly different for patients stratified by race. CONCLUSIONS: Surface image guidance is a viable alternative to scheduled mid-treatment imaging for monitoring intrafraction motion during stereotactic radiosurgery with automated delivery.

Determination of the Optimal Procalcitonin Threshold for Infection in Patients With Impaired Renal Function at a Community Hospital.

Background: Procalcitonin (PCT) is a biomarker that can help identify bacterial infections but can be difficult to interpret in the presence of renal dysfunction, which can elevate PCT even in the absence of infection. Objective: To determine the optimal PCT threshold to identify infection in patients with renal dysfunction and pneumonia or sepsis. Methods: A retrospective analysis was performed for inpatients with creatinine clearance of ≤60 mL/min and PCT level from 2018 to 2019. A pharmacist blinded to study outcomes classified patients as infected or noninfected based on predetermined criteria. Receiver operating characteristic curve analysis was performed to establish the optimal PCT threshold overall, as well as in subgroups of patients with chronic kidney disease (CKD), acute kidney injury (AKI), and end-stage renal disease (ESRD). Institutional review board approval was obtained. Results: A total of 198 patients were included in the study (99 infected, 99 noninfected). The optimal threshold in the AKI, CKD, and ESRD subgroups was determined to be 1.5 ng/mL, 0.1 ng/mL, and 1.75 ng/mL, respectively. Conclusion: The results of this study show that PCT thresholds were specific to type of renal dysfunction. These results differ from the traditionally accepted PCT threshold of 0.5 ng/mL for sepsis and 0.25 mg/mL for pneumonia. Future studies should confirm the appropriate PCT threshold in ESRD and CKD patient populations.