Effect modification of dosing strategy (AUC or trough) on AKI associated with vancomycin in combination with piperacillin/tazobactam or cefepime and meropenem

Piperacillin-tazobactam (TZP), cefepime (FEP), or meropenem (MEM) and vancomycin (VAN) are commonly used in combination for sepsis. Studies have shown an increased risk of acute kidney injury (AKI) with TZP and VAN compared to FEP or MEM. VAN guidelines recommend area under the curve (AUC) monitoring over trough (Tr) to minimize the risk of AKI. We investigated the association of AKI and MAKE-30 with the two VAN monitoring strategies when used in combination with TZP or FEP/MEM. Adult patients between 2015 and 2019 with VAN > 72 hours were included. Patients with AKI prior to or within 48 hours of VAN or baseline CrCl of ≤30 mL/min were excluded. Four cohorts were defined: FEP/MEM/Tr, FEP/MEM/AUC, TZP/Tr, and TZP/AUC. A Cox Proportional Hazard Model was used to model AKI as a function of the incidence rate of at-risk days, testing monitoring strategy as a treatment effect modification. Multivariable logistic regression was used to model MAKE-30. Overall incidence of AKI was 18.6%; FEP/MEM/Tr = 115 (14.6%), FEP/MEM/AUC = 52 (14.9%), TZP/Tr = 189 (26%), and TZP/AUC = 96 (17.1%) (P < 0.001). Both drug group [(TZP; P = 0.0085)] and monitoring strategy [(Tr; P = 0.0007)] were highly associated with the development of AKI; however, the effect was not modified with interaction term [(TZP*Tr); 0.085)]. The odds of developing MAKE-30 were not different between any group and FEP/MEM/AUC. The effect of VAN/TZP on the development of AKI was not modified by the VAN monitoring strategy (AUC vs trough). MAKE-30 outcomes were not different among the four cohorts.

Vancomycin AUC0-24 estimation using first-order pharmacokinetic methods in pediatric patients

INTRODUCTION

The optimal dosing and monitoring of vancomycin in pediatrics is still unknown but has evolved to emphasize area under the curve over 24 h (AUC0-24) over minimum concentration (Cmin) monitoring. Real-world data supporting the feasibility of two-concentration kinetics with first-order equations for the estimation of vancomycin AUC0-24 in pediatric patients are lacking.

OBJECTIVES

To describe the interplay of vancomycin dose, AUC0-24, and Cmin using first-order equations within four pediatric age groups.

METHODS

This is a single-center, retrospective cohort study analyzing pediatric patients (<18 years) receiving intravenous vancomycin between 2020 and 2022. Included patients received at least 24 h of intravenous vancomycin with two concentrations obtained within 96 h of therapy initiation. Patients with baseline renal dysfunction were excluded. Patients were divided into four age categories: neonates (≤28 days), infants (29 days to <1 year), children (1-12 years), and adolescents (13-17 years). First-order equations were utilized to estimate pharmacokinetic parameters and AUC0-24.

RESULTS

Overall, 219 patients (median age of 6 years [IQR 1-12]) met inclusion criteria. The median vancomycin daily dose was 30 mg/kg in neonates, 70 mg/kg in infants and children, and 52 mg/kg in adolescents. Median Cmin and AUC0-24 values among all age groups were 8.68 mg/L and 505 mg * h/L, respectively. For AUC0-24 values outside of the therapeutic range (400-600 mg * h/L), more values were SUPRAtherapeutic (>600 mg * h/L) than SUBtherapeutic (<400 mg * h/L). The overall trend within our data showed suboptimal correlation between Cmin and AUC0-24. However, 71% of patients with Cmin values of 5-10 mg/L had an AUC0-24 within the therapeutic range of 400-600 mg * h/L, whereas 23 patients (92%) with a SUPRAtherapeutic AUC0-24 had a Cmin value ≥15 mg/L. Approximately 10% of patients experienced acute kidney injury.

CONCLUSIONS

Our data describe the relationship between vancomycin dose, Cmin, and AUC0-24 in pediatric patients. We demonstrated the feasibility of using first-order equations to estimate AUC0-24, using two concentrations obtained at steady state to monitor efficacy and safety in pediatric patients receiving intravenous vancomycin. Our data showed suboptimal correlation between AUC0-24 and Cmin, which indicates that Cmin should not be used as a surrogate marker for a therapeutic AUC0-24 in pediatric patients. In alignment with the 2020 vancomycin consensus guidelines, we suggest utilizing AUC0-24 for efficacy and safety monitoring.

Performance of ePlex® blood culture identification panels in clinical isolates and characterization of antimicrobial stewardship opportunities

We assessed the performance of GenMark's ePlex® Blood Culture Identification (BCID) Panels for overall agreement of organism identification and resistance mechanism detection with standard microbiologic methods. This study included patients with a positive blood culture from May 2020 to January 2021. The primary outcomes were to assess concordance of ePlex® organism identification with standard identification methods and concordance of ePlex® genotypic resistance mechanism detection with standard phenotypic susceptibility testing. Secondary outcomes included panel specific performance and characterization of antimicrobial stewardship opportunities. The overall identification concordance rate in 1276 positive blood cultures was 98.1%. The overall concordance for the presence of resistance markers was 98.2% and concordance for the absence of resistance markers was 100%. A majority of ePlex® results (69.5%) represented opportunities for potential antimicrobial stewardship intervention. High concordance rates between the ePlex® BCID panels and standard identification and susceptibility methods enable utilization of results to guide rapid antimicrobial optimization.

Association of vancomycin-induced acute kidney injury with trough versus AUC monitoring in patients receiving extended durations of therapy

Objective

Vancomycin therapy is associated with an increased risk of acute kidney injury (AKI). Previous studies suggest that area under the curve (AUC) monitoring reduces the risk of AKI, but literature is lacking to support this in patients receiving longer durations of vancomycin therapy.

Design

Retrospective cohort study.

Method

Patients ≥18 years old, admitted between August 2015 and July 2017 or October 2017 and September 2019, and received at least 14 days of intravenous (IV) vancomycin therapy were included in the study. Our primary outcome was the incidence of AKI between trough monitoring and AUC monitoring groups using Kidney Disease Improving Global Outcomes criteria. Secondary outcomes included inpatient mortality, median inpatient length of stay, and median intensive care unit length of stay.

Results

Overall, 582 patients were included in the study, with 318 patients included in the trough monitoring group and 264 included in the AUC monitoring group. The median duration of vancomycin therapy was 23 days (interquartile range, 16-39). Patients within the trough monitoring group had a higher incidence of AKI compared to the AUC monitoring group (45.6% vs 28.4%, p < 0.001). Furthermore, logistic regression analysis showed that AUC monitoring was associated with a 54% lower incidence of AKI (OR 0.46, 95% CI [0.31-0.69]). All-cause inpatient mortality was numerically higher in the trough monitoring group (12.9% vs 8.3%, p = 0.078).

Conclusions

In patients who received at least 14 days of IV vancomycin therapy, AUC monitoring was associated with a lower incidence of AKI.

A comparison of active versus passive methods of responding to rapid diagnostic blood culture results

OBJECTIVE

To compare 2 methods of communicating polymerase chain reaction (PCR) blood-culture results: active approach utilizing on-call personnel versus passive approach utilizing notifications in the electronic health record (EHR).

DESIGN

Retrospective observational study.

SETTING

A tertiary-care academic medical center.

PATIENTS

Adult patients hospitalized with ≥1 positive blood culture containing a gram-positive organism identified by PCR between October 2014 and January 2018.

METHODS

The standard protocol for reporting PCR results at baseline included a laboratory technician calling the patient's nurse, who would report the critical result to the medical provider. The active intervention group consisted of an on-call pager system utilizing trained pharmacy residents, whereas the passive intervention group combined standard protocol with real-time in-basket notifications to pharmacists in the EHR.

RESULTS

Of 209 patients, 105, 61, and 43 patients were in the control, active, and passive groups, respectively. Median time to optimal therapy was shorter in the active group compared to the passive group and control (23.4 hours vs 42.2 hours vs 45.9 hours, respectively; P = .028). De-escalation occurred 12 hours sooner in the active group. In the contaminant group, empiric antibiotics were discontinued faster in the active group (0 hours) than in the control group and the passive group (17.7 vs 7.2 hours; P = .007). Time to active therapy and days of therapy were similar.

CONCLUSIONS

A passive, electronic method of reporting PCR results to pharmacists was not as effective in optimizing stewardship metrics as an active, real-time method utilizing pharmacy residents. Further studies are needed to determine the optimal method of communicating time-sensitive information.

Comparison of Bayesian-derived and first-order analytic equations for calculation of vancomycin area under the curve

INTRODUCTION

Consensus guidelines recommend targeting a vancomycin area under the curve to minimum inhibitory concentration (AUC₂₄ :MIC) ratio of 400-600 to improve therapeutic success and reduce nephrotoxicity. Although guidelines specify either Bayesian software or first-order equations may be used to estimate AUC₂₄ , there are currently no large studies directly comparing these methods.

OBJECTIVE

To compare calculated vancomycin AUC₂₄ using first-order equations with two-drug concentrations at steady state to Bayesian two- and one-concentration estimations.

METHODS

This was a single-center, retrospective cohort study of 978 adult hospitalized patients receiving intravenous vancomycin between 2017 and 2019. Patients were included if they received at least 72 h of vancomycin and had two-serum drug concentrations obtained. AUC₂₄ was calculated using first-order analytic (linear), Bayesian two-concentration, and Bayesian one-concentration methods for each patient. The InsightRx™ software platform was used to calculate Bayesian AUC₂₄ . Pearson's correlation and clinical agreement (based on AUC₂₄  classified as subtherapeutic, therapeutic, or supratherapeutic) were used to assess agreement between methods. Bland-Altman plots were used to assess mean difference (MD) and 95% limits of agreement (LOA).

RESULTS

Excellent agreement was observed between linear and Bayesian two-concentration methods (r = 0.963, clinical agreement = 87.4%) and Bayesian two-concentration and one-concentration methods (r = 0.931, clinical agreement = 88.5%); however, a degree of variability was noted with 95% LOA -99 to 76 (MD = -11.5 mg*h/L) and -92 to 113 (MD = -10.4 mg*h/L), for the respective comparisons. The agreement between linear and Bayesian one-concentration approaches was less than prior comparisons (r = 0.823, clinical agreement = 76.8%) and demonstrated the greatest amount of variability with 95% LOA -197 to 153 (MD = -21.9 mg*h/L).

CONCLUSIONS

Linear and Bayesian two-concentration methods demonstrated high-level agreement with acceptable variability and may be considered comparable to estimate vancomycin AUC₂₄ . As linear and Bayesian one-concentration methods demonstrated significant variability and suboptimal agreement, concerns exist surrounding the interchangeability of these methods in clinical practice, particularly at higher extremes of AUC₂₄ .

Efficacy and safety of vancomycin loading doses in critically ill patients with methicillin-resistant Staphylococcus aureus infection

Background

While vancomycin loading doses may facilitate earlier pharmacokinetic-pharmacodynamic target attainment, the impact of loading doses on clinical outcomes remains understudied. Critically ill patients are at highest risk of morbidity and mortality from methicillin resistant Staphylococcus aureus (MRSA) infection and hypothesized to most likely benefit from a loading dose. We sought to determine the association between receipt of a vancomycin loading dose and clinical outcomes in a cohort of critically ill adults.

Methods

Four hundred and forty-nine critically ill patients with MRSA cultures isolated from blood or respiratory specimens were eligible for the study. Cohorts were established by receipt of a loading dose (⩾20 mg/kg actual body weight) or not. The primary outcome was clinical failure, a composite outcome of death within 30 days of first MRSA culture, blood cultures positive ⩾7 days, white blood cell count up to 5 days from vancomycin initiation, temperature up to 5 days from vancomycin initiation, or substitution (or addition) of another MRSA agent.

Results

There was no difference in the percentage of patients experiencing clinical failure between the loading dose and no loading dose groups (74.8% versus 72.8%; p = 0.698). Secondary outcomes were also similar between groups, including mortality and acute kidney injury, as was subgroup analysis based on site of infection. Exploratory analyses, including assessment of loading dose based on quartiles and a multivariable logistic regression model showed no differences.

Conclusion

Use of vancomycin loading doses was not associated with improved clinical outcomes in critically ill patients with MRSA infection.

First-Dose Vancomycin Pharmacokinetics Versus Empiric Dosing on Area-Under-the-Curve Target Attainment in Critically Ill Patients

BACKGROUND

Early attainment of target area under the curve (AUC) to minimum inhibitory concentration (MIC) ratios have been associated with clinical success, as well as lower incidence of acute kidney injury (AKI), in patients receiving vancomycin for methicillin-resistant Staphylococcus aureus (MRSA). Critically ill patients are particularly vulnerable to poor outcomes from infection and face multiple risk factors for AKI, thus early precision dosing of vancomycin is vital in this population. We hypothesized that a personalized dosing approach, using vancomycin levels obtained after the first dose to guide further dosing, would be superior to empiric dosing in terms of AUC target attainment assessed at steady state (SS).

METHODS

A retrospective cohort study of 66 critically ill adult patients admitted to the medical intensive care unit without AKI and receiving vancomycin with at least two SS concentrations obtained for AUC calculation was performed. Patients were separated into cohorts based on whether they had two concentrations assessed after the first dose of vancomycin and were subsequently dosed based on personalized pharmacokinetic calculations (first-dose kinetics) or whether they were empirically dosed using population estimates. The primary outcome was AUC target attainment (400-600 mg hour/L) at SS.

RESULTS

Compared with patients receiving empiric dosing by population estimates, using first-dose kinetics to guide subsequent dosing resulted in significantly greater AUC target attainment at SS (58.6% first-dose vs 32.4% empiric; p=0.033). Patients dosed empirically yielded more variable AUC values across a wide range compared with the first-dose kinetics group (coefficient of variation 40.7% empiric vs 26.1% first-dose). There was no difference in AKI up to 48 hours after SS concentrations between the two dosing schemes.

CONCLUSIONS

A dosing strategy using two vancomycin serum concentrations after the first dose and calculating personalized pharmacokinetic parameters to guide subsequent dosing is associated with greater AUC target attainment at SS compared with empiric dosing of vancomycin in critically ill adults with relatively stable renal function.

Pharmacist Survey: Pharmacist Perception of Vancomycin Area Under the Curve Therapeutic Drug Monitoring

BACKGROUND

Evidence suggests the standard vancomycin trough goal of 15 to 20 mg/L for serious Staphylococcus aureus infections is associated with acute kidney injury, whereas appropriate monitoring of 24-hour area under the curve (AUC) may decrease nephrotoxicity. As a result, institutions have transitioned to AUC monitoring, the predictive pharmacokinetic/pharmacodynamic parameter of vancomycin to improve safety outcomes. However, this method may require increased pharmacist time and effort. Pharmacist perception of the practice change is largely unknown and warrants investigation.

METHODS

An electronic survey was disseminated via e-mail to pharmacists 5 months post-AUC implementation. Items of interest were focused on pharmacist perception, including quantity of patients monitored using AUC, justification of the practice change, differences in efficacy and safety, and changes in monitoring time requirements.

RESULTS

The pharmacist survey was distributed to 196 pharmacists and 84 responded (43% response rate). Eighty-one pharmacists had monitored patients using AUC methods. Sixty-nine percent of these respondents perceived the change to result in increased or slightly increased patient safety, 27% described no difference, and 4% stated safety was decreased or slightly decreased. Forty-two percent perceived the transition to result in increased or slightly increased efficacy, while 48% noted no difference and 10% responded that efficacy was decreased or slightly decreased. Pharmacists stated the creation of an institutional calculator decreased the time required to calculate AUC.

CONCLUSION

After the change to AUC monitoring, pharmacists perceived improvements in safety outcomes while efficacy was at least similar if not increased.

Vancomycin Area Under the Curve Dosing and Monitoring at an Academic Medical Center: Transition Strategies and Lessons Learned

Due to the inconsistent correlation of vancomycin trough concentrations with 24-hour area under the curve (AUC) and a desire to reduce rates of vancomycin-associated acute kidney injury, an institutional guideline was implemented by the Antimicrobial Stewardship Team in September 2017 to monitor vancomycin using AUC. Three stages were utilized to organize the process: preparation, implementation, and evaluation. The preparation stage was used to present literature to key stakeholders, and pharmacy meetings focused on the development of a dosing and monitoring guideline. Along with institution-wide education, the implementation stage included information technology development and support. The evaluation stage was comprised of quality improvement and clinical research. Future plans include dissemination of the results and analyses. Numerous lessons were learned due to barriers experienced during the process, but the transition was successful.

1804. Impact of Susceptibility Testing Method on Antibiotic Selection for Methicillin-Resistant Staphylococcus Aureus (MRSA) Bacteremia

Background

The selection of intravenous (IV) antibiotics for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia can be influenced by the vancomycin minimum inhibitory concentration (MIC). This study explores the changes in antibiotic use and inpatient mortality for patients with MRSA bacteremia after switching the MIC testing methods.

Methods

At University of Kentucky Medical Center, Etest™ was implemented in November 2013 for all Staphylococcus aureus blood isolates. In April 2016, this was changed to Phoenix™ automated system. Data regarding antibiotic usage for patients with MRSA bacteremia were collected from July 2014 to December 2015 (Etest™) and September 2016 to March 2017 (Phoenix™). Only patients started on IV vancomycin were included. Daptomycin and ceftaroline use was monitored by the antimicrobial stewardship team with focus on guideline adherence.

Results

A total of 119 and 62 patients were identified before and after switching to Phoenix™. MICs of 2 μg/mL were significantly decreased (P < 0.001) after changing to Phoenix™ (Table 1). Daptomycin use (alone or in combination) decreased from 37% (44/119) to 21% (13/62) (P = 0.013). Ceftaroline use (alone or in combination) decreased from 32% (38/119) to 19% (12/62) (P = 0.036). The reason for escalation in 13 of 44 (30%) patients with daptomycin and 6 of 38 (16%) patients with ceftaroline was an MIC of 2 μg/mL. Overall, IV vancomycin use (alone or in combination) increased from 50% (60/119) to 69% (43/62) (P = 0.007). All-cause inpatient mortality was 16% (19/119) before and 10% (6/62) (P = 0.24) after switching to Phoenix.

Conclusion

A switch in vancomycin susceptibility testing from Etest™ to Phoenix™ automated system was associated with a significant decrease in daptomycin and ceftaroline use and an increase in IV vancomycin use without any change in all-cause inpatient mortality.

Disclosures

All authors: No reported disclosures.

2436. Use of Piperacillin/Tazobactam vs. Cefepime or Carbapenem for Infections Due to Serratia, Citrobacter, or Enterobacter

Background

Methods

Results

Conclusion

Disclosures

1026. Trends in Infective Endocarditis During the Substance Use Disorder Epidemic at an Academic Medical Center

Background

In many areas of the United States, substance use disorders (SUD) have increased dramatically over the past decade. Overdose deaths have increased as well, and Kentucky ranks among the nation’s leaders in deaths per 100,000 population. Infective endocarditis (IE) is a well-known complication of intravenous drug use, contributing to significant morbidity and mortality, but few studies have evaluated the effect of the current SUD epidemic on rates and demographics of IE. We sought to examine the trends in IE and IE with SUD at our institution.

Methods

We collected data from patients admitted to a large academic medical center in Kentucky between January 1, 2013 and December 31, 2016. Patients were classified according to the International Classification of Diseases, Tenth Revision. Patients were considered to have IE if they received codes I33 or I38. Patients were considered to have an SUD if they received codes F11.10, F15.10, F14.10, F19.10, or Z86.59. Data were collected through the TriNetX database (TriNetX, Cambridge, MA).

Results

There were 2,100 cases of IE during the study period. The mean (SD) age was 53 years (21). Of those, 440 also had an SUD. The mean (SD) age of these patients was 41 years (11). Patients in both the IE and IE/SUD categories were primarily male (54% and 55%) and white (94% and 94%). The number of cases of IE increased from 190 in 2013 to 430 in 2016 (R² = 0.9877). The number of IE cases diagnosed as having an SUD increased from 30 (16% of all IE cases) in 2013 to 130 (30% of all IE cases) in 2016 (R² = 0.7352 for the trend). This increase in cases corresponds to a 333% increase in the number of cases of IE with SUD.

Conclusion

Between 2014 and 2016, opioid overdose deaths in Kentucky rose from 24.7 to 33.5 per 100,000 population, a 35.6% increase. During a similar timeframe, the number of IE cases associated with SUD at our institution rose 333%. While it is possible that increased coding of substance use disorders factored into this dramatic increase, it appears that the number of IE cases associated with SUD is rising at a disproportionately rapid rate.

Disclosures

All authors: No reported disclosures.

1878. Expanding Kentucky’s “One and Done” Tradition: Lipoglycopeptide Administration in the Emergency Department at a Tertiary, Academic Medical Center

Background

Acute bacterial skin and skin structure infection (ABSSSI) incidence continues to rise, accounting for around 3.5 million emergency department (ED) visits per year in the United States. Dalbavancin and oritavancin are lipoglycopeptides with long half-lives allowing for single dose treatment options for eligible patients presenting with ABSSSIs in the ED, avoiding an inpatient admission. The objective of this study was to investigate the financial outcomes of utilizing these agents in the ED.

Methods

This was a single-center, retrospective study in adult patients with ABSSSIs that received a lipoglycopeptide in the ED at an academic medical center from April 2016 to February 2018. A multidisciplinary institutional guideline was developed and implemented in April 2016. Data were documented in the electronic medical record and/or REDCap™ database. A comparator group was identified by utilizing similar ICD-10 codes for patients that were admitted for ABSSSI. Variable direct cost-avoidance was examined to explore the financial implication of lipoglycopeptide treatment in this population.

Results

The average length of stay in the comparator group who were admitted for ABSSSIs during the predefined time period was 4.3 days. Because patients receiving a lipoglycopeptide did not require admission for intravenous antibiotics, 94.6 patient-days were avoided increasing the capacity by 14.1 patients. Overall, 22 patients received either dalbavancin (n = 18) or oritavancin (n = 4). The age was 40.8 ± 13.2 years for the study group with 55% male. The age of the comparator group was 40.5 ± 19.7 years. All patients were discharged home from the ED without being admitted. Two patients were readmitted for treatment failure requiring IV antibiotics. Despite 2 of 22 patients receiving a lipoglycopeptide without insurance, the variable direct cost avoidance was $4,560 per case, or $1,060 per day.

Conclusion

The use of lipoglycopeptides offers patient convenience and financial benefits, warranting its consideration for use in the ED at tertiary academic medical centers.

Disclosures

All authors: No reported disclosures.

1071. Impact of Standard vs. Prolonged Courses of Antibiotics for the Treatment of Uncomplicated Staphylococcus aureus Bacteremia (SAB) in Patients With Hematologic Malignancies

Background

The optimal treatment duration for uncomplicated SAB (U-SAB) is unknown in patients with hematologic malignancies. The goal of this study was to evaluate the impact of antibiotic duration on outcomes in patients with hematologic malignancies and U-SAB.

Methods

This was a multicenter, retrospective cohort study of adult patients with hematologic malignancies and U-SAB treated with standard (2 weeks) or prolonged (>2 weeks) antibiotic therapy. U-SAB was defined as defervescence and culture clearance within 96 hours of index culture and the absence of: endocarditis, implanted prostheses, metastatic sites of infection, and bone/joint involvement. Patients with SAB therapy <10 days and those with inadequate source control were excluded. The primary outcome was a composite global clinical cure: absence of relapse SAB, absence of SAB progression, and survival at 60 days following index SAB.

Results

Of 89 included patients, 51% received a standard antibiotic duration for U-SAB. The median age of the entire cohort was 56 and majority was male (60%). Neutropenia was present at index culture in 53% of patients, and acute leukemia (48%) and lymphoma (26%) were the most common underlying malignancies. Other baseline characteristics were similar between the two groups except more patients in the standard duration group had relapsed/refractory malignancy (51% vs. 25%, P = 0.016), central-line source (71% vs. 48%, P = 0.032), and antibiotic prophylaxis prior to index SAB (42% vs. 18%, P = 0.021). Median duration of treatment in the standard group was 15 days vs. 28 days in the prolonged duration group. No differences in global clinical cure and other clinical outcomes were seen between groups (Figure 1). On multivariable logistic regression analysis, only relapsed/refractory malignancy was identified as an independent predictor of global clinical failure (odds ratio, OR, 9.43; 95% confidence interval, CI, 1.17–76.9; P = 0.035). Duration of treatment was not associated with global clinical cure (OR, 2.92; 95% CI, 0.51–16.7; P = 0.23).

Conclusion

No differences in clinical outcomes were seen in patients with active hematologic malignancies who received 2 weeks vs. >2 weeks of antibiotic therapy for the treatment of U-SAB, although confirmation of our findings in a larger study is warranted.

Disclosures

All authors: No reported disclosures.

529. Overdiagnosis of Clostridioides difficile with a Multiplex PCR Panel

Background

While advantageous by casting a wider diagnostic net, multiplex panels can be problematic if the pretest probability is low. A significant increase in reported Clostridioides difficile infections (CDI) was noted at our institution following introduction of a multiplex comprehensive GI (CGI) panel which includes an analyte for C. difficile. Owing to these concerns, the C. difficile analyte result was suppressed when reporting and providers were advised to order a standalone C. difficile PCR (CDPCR) test if CDI was a concern. The objective of this study was to investigate concerns of false positive C. difficile results from the CGI panel.

Methods

C. difficile diagnostic practices were prospectively evaluated from April to August 2017. Patient charts were reviewed in response to a positive C. difficile analyte on the CGI panel. CDPCR results were reviewed if ordered. If not ordered, chart review and discussion with the provider was conducted to investigate clinical suspicion for CDI. The results were analyzed to examine the performance of the C. difficile analyte on the CGI panel.

Results

Overall, a total of 1,611 CGI panels were performed with C. difficile being detected in 156 specimens. Of these positive results, a subanalysis was performed on 123 positive specimens for whom complete data was available. A CDPCR was performed in 80 (65%) of these specimens. Among those, only 44 (55%) were CDPCR positive and 22 (28%) were CDPCR negative (likely a false-positive CGI result), and 14 (17%) were rejected because of specimen consistency. For the remaining 43 C. difficile-positive CGI panel specimens that did not have an accompanying CDPCR, seven were in children below 2 years of age. Direct provider discussion occurred in the remaining 36 cases. Providers declined CDPCR testing in 24 of those cases due to a lack of clinical concern.

Conclusion

The use of the CGI panel for C. difficile led to over diagnosis of CDI. This could have significant consequences for clinical care and the reporting of hospital acquired infections.

Disclosures

All authors: No reported disclosures.

Subtherapeutic voriconazole concentrations associated with concomitant dexamethasone: case report and review of the literature

WHAT IS KNOWN AND OBJECTIVE

Voriconazole has significant drug interactions due to metabolism by CYP enzymes. Subtherapeutic voriconazole concentrations associated with concomitant dexamethasone are not well described.

CASE DESCRIPTION

An 84-year-old male was started on voriconazole for a fungal brain abscess. He was readmitted due to clinical failure thought to be the result of subtherapeutic voriconazole concentrations. Dexamethasone was identified as a potential cause due to its induction of CYP enzymes. This interaction was substantiated by sequential troughs that demonstrated a rise in voriconazole concentrations as dexamethasone was tapered off.

WHAT IS NEW AND CONCLUSION

Therapeutic drug monitoring for patients on voriconazole and dexamethasone is essential to prevent suboptimal clinical outcomes.

Pharmacist perception and use of UpToDate®

A cross-sectional survey of a convenience sample of 1,199 pharmacists was conducted to describe pharmacists' use and perception of UpToDate®. Of 472 (39%) respondents, 217 (46%) reported using UpToDate. Most respondents who used or had heard of UpToDate indicated willingness to change a treatment plan based on UpToDate recommendations (77%). Many believed that UpToDate is updated weekly (31%) or monthly (49%) and that all articles undergo external peer review (51%). In conclusion, the majority of respondents reported that they would adjust drug therapy based on UpToDate recommendations; however, many pharmacists may hold misconceptions regarding the updating and peer-review processes.

Interleukin-10/Ceftriaxone prevents E. coli-induced delays in sensorimotor task learning and spatial memory in neonatal and adult Sprague-Dawley rats

Intrauterine infection during pregnancy is associated with early activation of the fetal immune system and poor neurodevelopmental outcomes. Immune activation can lead to alterations in sensorimotor skills, changes in learning and memory and neural plasticity. Both interleukin-10 (IL-10) and Ceftriaxone have been shown to decrease immune system activation and increase memory capacity, respectively. Using a rodent model of intrauterine infection, we examined sensorimotor development in pups, learning and memory, via the Morris water maze, and long-term potentiation in adult rats. Pregnant rats at gestational day 17 were inoculated with 1 x 10(5) colony forming units of Escherichia coli (E. coli) or saline. Animals in the treatment group received IL-10/Ceftriaxone for 3 days following E. coli administration. Intrauterine infection delayed surface righting, negative geotaxis, startle response and eye opening. Treatment with IL-10/Ceftriaxone reduced the delay in these tests. Intrauterine infection impaired performance in the probe trial in the Morris water maze (saline 25.13+/-1.01; E. coli 20.75+/-1.01; E. coli+IL-10/Ceftriaxone 20.2+/-1.62) and reduced the induction of long-term potentiation (saline 141.5+/-4.3; E. coli 128.7+/-3.9; E. coli+IL-10/Ceftriaxone 140.0+/-10). In summary, the results of this study indicate that E. coli induced intrauterine infection delays sensorimotor and learning and memory, while IL-10/Ceftriaxone rescues some of these behaviors. These delays were also accompanied by an increase in interleukin-1beta levels, which indicates immune activation. IL-10/Ceftriaxone prevents these delays as well as decreases E. coli-induced interleukin-1beta activation and may offer a window of time in which suitable treatment could be administered.

Oropharyngeal Scintigraphy: A Reliable Technique for the Quantitative Evaluation of Oral–Pharyngeal Swallowing

A valid and reliable technique to quantify the efficiency of the oral-pharyngeal phase of swallowing is needed to measure objectively the severity of dysphagia and longitudinal changes in swallowing in response to intervention. The objective of this study was to develop and validate a scintigraphic technique to quantify the efficiency of bolus clearance during the oral-pharyngeal swallow and assess its diagnostic accuracy. To accomplish this, postswallow oral and pharyngeal counts of residual for technetium-labeled 5- and 10-ml water boluses and regional transit times were measured in 3 separate healthy control groups and in a group of patients with proven oral-pharyngeal dysphagia. Repeat measures were obtained in one group of aged (> 55yr) controls to establish test-retest reliability. Scintigraphic transit measures were validated by comparison with radiographic temporal measures. Scintigraphic measures in those with proven dysphagia were compared with radiographic classification of oral vs. pharyngeal dysfunction to establish their diagnostic accuracy. We found that oral ( p = 0.04), but not pharyngeal, isotope clearance is swallowed bolus-dependently. Scintigraphic transit times do not differ from times derived radiographically. All scintigraphic measures have extremely good test-retest reliability. The mean difference between test and retest for oral residual was -1% (95% CI -3%-1%) and for pharyngeal residual it was -2% (95% CI -5%-1%). Scintigraphic transit times have very poor diagnostic accuracy for regional dysfunction. Abnormal oral and pharyngeal residuals have positive predictive values of 100% and 92%, respectively, for regional dysfunction. We conclude that oral-pharyngeal scintigraphic clearance is highly reliable, bolus volume-dependent, and has a high predictive value for regional dysfunction. It may prove useful in assessment of dysphagia severity and longitudinal change.

Reduced placental perfusion causes an increase in maternal serum leptin

OBJECTIVE

We tested the hypothesis that the inadequately perfused placenta increases production of leptin, which can be detected in maternal serum.

STUDY DESIGN

Sprague-Dawley rats (n=13), on day 14 of gestation, had placement of clips on the aorta and the ovarian arteries providing 35 per cent occlusion of the vessels. Eight rats had sham surgery and 14 rats served as non-surgical controls. All animals were sacrificed on day 19 of gestation. Maternal serum was obtained, and pups and placentae were weighed.

RESULTS

Both placental weights and pup weights were reduced due to reduced uterine perfusion and were negatively correlated with maternal serum leptin (P=0.018 and 0.028, respectively). Maternal serum leptin was increased in the treatment group (2.21 ng/ml+/-64 ng/ml) compared to controls (1.66 ng/ml+/-38 ng/ml) (P=0.031).

CONCLUSIONS

Our findings suggest that reduced placental perfusion results in an increase in maternal serum leptin. Further investigation is needed to determine if maternal serum leptin may be useful in identifying pregnancies with uteroplacental insufficiency.

Intravenous pyridoxine-induced metabolic acidosis

STUDY OBJECTIVE

Pyridoxine hydrochloride, the antidote for isonicotinic acid hydrazide (INH)--induced seizures, is available in solution at a concentration of 100 mg/mL at a pH of less than 3. Pyridoxine is often infused rapidly in large doses for INH-induced seizures. Effects of pyridoxine infusion on base deficit in amounts given for INH poisoning have not been studied in human subjects. We hypothesized that this infusion would result in transient worsening of acidosis.

METHODS

We conducted a randomized, controlled crossover trial in human volunteers. Five healthy volunteers (mean age, 35 years; range, 29 to 43 years) were randomized to receive intravenous placebo (50 mL of normal saline solution) or 5 g of pyridoxine (50 mL) over 5 minutes. A peripheral intravenous catheter was established in each arm, and a heparinized venous blood sample was obtained for base deficit at baseline and 3, 6, 10, 20, and 30 minutes after infusion. After at least a 1-week washout period, the volunteers were assigned to the alternate arms of the experiments, thus acting as their own control subjects. Data were analyzed by using the 2-tailed paired t test, controlling for multiple comparisons.

RESULTS

No difference was noted between groups at baseline. A statistically significant increased base deficit was noted after the pyridoxine infusion versus control at 3 to 20 minutes but not at 30 minutes (P =.1). Maximal mean increase in base deficit (2.74 mEq/L) was noted at 3 minutes.

CONCLUSION

A transient increase in base deficit occurs after the infusion of 5 g of pyridoxine in normal volunteers.

Diagnostic use of physicians' detection of urine fluorescence in a simulated ingestion of sodium fluorescein-containing antifreeze

STUDY OBJECTIVE

We sought to assess physicians' ability to accurately determine the presence or absence of sodium fluorescein (SF) in urine at a concentration corresponding to that present after ingestion of a toxic amount of commercial automotive antifreeze.

METHODS

We studied 2 different urine specimen evaluation formats--one presenting isolated specimens, and the other presenting specimens grouped for comparison--to determine whether the visual clues afforded by grouped comparison aided the accuracy of the evaluation. On each study day, 3 urine specimens (1 control specimen obtained before SF administration and 2 specimens obtained after SF administration) were obtained from each of 9 or 10 volunteers. Each of these 27 or 30 urine specimens were presented sequentially and in random order to 2 emergency physicians during separate evaluation time periods. Each physician was asked to classify each specimen as fluorescent or nonfluorescent (sequential format). After a rest period, each physician, again separately, was asked to look at the same 27 or 30 urine specimens, this time all together in a test tube rack so that grouped comparisons were possible. The physicians again classified each sample as either fluorescent or nonfluorescent (grouped format). We assessed sensitivity, specificity, and accuracy of the evaluation by each presentation format (sequential or grouped).

RESULTS

Mean examiner sensitivity, specificity, and accuracy for detecting the presence of SF in urine using the sequential presentation format were 35%, 75%, and 48%, respectively, whereas the same test performance indices were 42%, 66%, and 50%, respectively, when the grouped format was used.

CONCLUSION

Wood's lamp determination of urine fluorescence is of limited diagnostic utility in the detection of SF ingestion in an amount equivalent to toxic ingestion of some ethylene glycol--containing automotive antifreeze products.

Development and validation of a self-report symptom inventory to assess the severity of oral-pharyngeal dysphagia

BACKGROUND & AIMS

The aim of this study was to develop and evaluate the validity and reliability of a self-report inventory to measure symptomatic severity of oral-pharyngeal dysphagia.

METHODS

Test-retest reliability and face, content, and construct validity of a prototype visual analogue scale inventory were assessed in 45 patients who had stable, neuromyogenic dysphagia.

RESULTS

Normalized scores varied over time by -0.5% +/- 17.6% (95% confidence interval, -9.2% to 8.2%). Factor analysis identified a single factor (dysphagia), to which 18 of 19 questions contributed significantly, that accounted for 56% of total variance (P < 0.0001). After deletion of 2 questions with poor face validity and patient compliance, this proportion increased to 59%; mean test-retest change was -2% (95% confidence interval, -11% to 7%); and total score correlated highly with an independent global assessment severity score (r = 0.7; P < 0.0001). A mean 70% reduction in score (P < 0.0001) was observed after surgery in patients with Zenker's diverticulum (discriminant validity).

CONCLUSIONS

Applied to patients with neuromyogenic dysphagia, the 17-question inventory shows strong test-retest reliability over 2 weeks as well as face, content, and construct validity. Discriminant validity (responsiveness) has been demonstrated in a population with a correctable, structural cricopharyngeal disorder. Responsiveness of the instrument to treatment in neuromyogenic dysphagia remains to be quantified.

Cricopharyngeal myotomy does not increase the risk of esophagopharyngeal acid regurgitation

OBJECTIVE

It is not known whether cricopharyngeal myotomy predisposes to esophagopharyngeal regurgitation. Using ambulatory, dual pharyngeal, and esophageal pH monitoring before and after cricopharyngeal myotomy, our aim was to determine the effect, if any, of myotomy on the frequency of esophagopharyngeal acid regurgitation.

METHODS

We studied prospectively 18 patients who underwent cricopharyngeal myotomy for pharyngeal dysphagia (10 Zenker's, eight neurogenic dysphagia), of whom 17 agreed to undergo dual pH monitoring preoperatively, and 10 who agreed to both pre- and postoperative monitoring.

RESULTS

Symptoms of gastroesophageal reflux disease were present in 30%. Cricopharyngeal myotomy significantly reduced basal upper esophageal sphincter pressure by 49%, from 37+/-5 mm Hg to 19+/-3 mm Hg (p = 0.007). Esophagopharyngeal regurgitation was a rare event and the frequency of it did not differ between patients and healthy controls. Preoperatively, three regurgitation events in two patients did not differ from the postoperative frequency of a total of two events in the same two patients.

CONCLUSIONS

Increased esophageal acid exposure is common and esophagopharyngeal regurgitation is rare in unselected patients undergoing cricopharyngeal myotomy for pharyngeal dysphagia. Myotomy does not increase the frequency of esophagopharyngeal acid regurgitation in such patients.

Esophagopharyngeal acid regurgitation: dual pH monitoring criteria for its detection and insights into mechanisms

BACKGROUND & AIMS

A valid technique for the detection of esophagopharyngeal acid regurgitation would be valuable to evaluate suspected reflux-related otolaryngologic and respiratory disorders. The aim of this study was to derive pH criteria that optimally define esophagopharyngeal acid regurgitation and to examine patterns of regurgitation.

METHODS

In 19 healthy controls and 15 patients with suspected regurgitation, dual or quadruple pH sensors were used to monitor pharyngeal and esophageal pH. For each combination of the 2 variables, DeltapH and nadir pH, proportions of pH decreases that occurred during or independent of esophageal acidification were calculated to determine the likelihood that an individual pharyngeal pH decrease was a candidate regurgitation event or a definite artifact.

RESULTS

Overall, 92% of pharyngeal pH decreases of 1-2 pH units and 66% of pH decreases of this magnitude reaching a nadir pH of <4 were artifactual. Optimal criteria defining a pharyngeal acid regurgitation event were a pH decrease that occurred during esophageal acidification, had a DeltapH of >2 units, and reached a nadir of <4 units in less than 30 seconds. Regurgitation occurred more frequently in subjects in an upright (32 of 35) than in a supine (3 of 35 events; P </= 0.0001) position and was more frequently abrupt (synchronous with esophageal acidification) than delayed (P </= 0.05).

CONCLUSIONS

Accepted criteria for gastroesophageal reflux are not applicable to the detection of esophagopharyngeal acid regurgitation, and most regurgitation occurs abruptly and in upright position.

Self-inflicted burn injuries: an 11-year retrospective study

The burns unit at the Royal Brisbane Hospital accepted a total of 2275 admissions from 1986 to 1996. During this 11-year period, 65 cases of self-inflicted burn injury were treated, which made up 2.9% of the total number of admissions. A mortality rate of 21.5% (14 patients) is noted, with all patients dying after admission to the hospital. A common feature of people that self-inflict burn injuries is a psychiatric history, with many patients having histories of self-harm or suicide attempts. Two distinct groups were identified--those with suicidal intent and those with intent of self-harm. Those patients with self-inflicted injuries have an increased mean of 31.4% total body surface area burned as compared with those patients whose injuries are accounted for as accidental, which have a mean total body surface area burned of 10%. Additionally, the mean length of stay in the hospital for patients with self-inflicted injuries was 40 days for acute injuries, which is prolonged; the mean length of stay for acute injuries that were not self-inflicted was 14 days. This investigation discovered 3 cases of repeated self-inflicted burn injury.

Acute cyanide toxicity caused by apricot kernel ingestion

A 41-year-old woman ingested apricot kernels purchased at a health food store and became weak and dyspneic within 20 minutes. The patient was comatose and hypothermic on presentation but responded promptly to antidotal therapy for cyanide poisoning. She was later treated with a continuous thiosulfate infusion for persistent metabolic acidosis. This is the first reported case of cyanide toxicity from apricot kernel ingestion in the United States since 1979.

Effect of magnesium hydroxide on iron absorption following simulated mild iron overdose in human subjects

OBJECTIVE

To determine the effect of oral magnesium hydroxide [Mg(OH)2] on iron absorption after simulated iron overdose in human subjects.

METHODS

A randomized, controlled crossover study was conducted in healthy adult male human volunteers taking no medications. Subjects received an average of 5.0 mg/kg elemental iron orally followed 1 hour later by either oral administration of 4.5 g of Mg(OH)2 per g ingested elemental iron or no treatment. Serial serum specimens were obtained over the 12 hours following iron ingestion and stored at -60 degrees C until standard serum iron assay was performed. After a 2-week washout period, the subjects were enrolled in the alternative trial arm. Individual baseline diurnal variation in serum iron levels was determined over a 12-hour period on the day prior to each trial. Area under time-concentration curves (AUCs) were calculated, and the AUC due to experimental iron ingestion (deltaAUC) was determined by subtracting the baseline diurnal AUC from the experimental AUC for each subject.

RESULTS

Thirteen healthy adult male subjects were enrolled. Mean +/- SEM for deltaAUC due to experimental iron ingestion followed by treatment with Mg(OH)2, 78 +/- 23 micromol(hr)/L, was significantly less than that followed by no treatment, 144 +/- 33 micromol(hr)/L (p = 0.03 by signed rank test).

CONCLUSIONS

Magnesium hydroxide, administered 1 hour post-iron ingestion at an oral dose of 4.5 g per g elemental iron ingested, significantly reduced iron absorption during a 12-hour period following simulated mild iron overdose in healthy adult human volunteers.

Influence of altered tongue contour and position on deglutitive pharyngeal and UES function

The potential influence of altered lingual position and contour during the bolus loading phase of the swallow in mediating the swallowed bolus volume-dependent regulation of upper esophageal sphincter (UES) relaxation and opening was studied in 15 healthy volunteers using simultaneous videoradiography and manometry. A maxillary dental splint modulated tongue deformity during the early oral phase of deglutition. We examined the effect of the splint and swallowed bolus density on bolus volume-dependent changes in the timing of events in the swallow sequence and on hypopharyngeal intrabolus and midpharyngeal pressures. Peak mid-pharyngeal pressure (P = 0.001) and hypopharyngeal intrabolus pressure (P = 0.04) were significantly reduced by the splint. The normal volume-dependent earlier onset of sphincter relaxation and opening was preserved with the splint in situ. The splint significantly delayed the onset of hyoid motion and UES relaxation and opening without influencing transit times or total swallow duration. Alterations in tongue contour and position reduce intrabolus pressure and pharyngeal contraction without influencing normal bolus volume-dependent regulation of timing of UES relaxation and opening.

Antibiotic-induced convulsions

Convulsive episodes are associated with the use of a number of antimicrobial agents. Although seizures may be a feature of the disease being treated, antibiotics should be considered possible causes of seizures, particularly if suggested by temporal relationships between seizure activity and drug administration. The astute clinician should be aware of the clinical settings in which antibiotic-induced seizures occur, be familiar with likely agents and their mechanisms of toxicity, and be prepared to institute appropriate management directed at this adverse effect of antimicrobial therapy.

Predictors of outcome following cricopharyngeal disruption for pharyngeal dysphagia

The indications for, and predictors of outcome following cricopharyngeal disruption in pharyngeal dysphagia are not clearly defined. Our purpose was to examine the symptomatic response to cricopharyngeal disruption, by either myotomy or dilatation, in patients with oral-pharyngeal dysphagia and to determine pre-treatment manometric or radiographic predictors of outcome. Using simultaneous pharyngeal videoradiography and manometry, we studied 20 patients with pharyngeal dysphagia prior to cricopharyngeal dilatation (n = 11) or myotomy (n = 8), and 23 healthy controls. We measured peak pharyngeal pressure, hypopharyngeal intrabolus pressure, upper esophageal sphincter diameter, and coordination. Response rate to sphincter disruption was 65%. The extent of sphincter opening was significantly reduced in patients compared with controls (p = 0.004), but impaired sphincter opening was not a predictor of outcome. Increased hypopharyngeal intrabolus pressures (> 19 mmHg for 10 ml bolus; > 31 mmHg for 20 ml bolus) was a significant predictor of outcome (p = 0.01). Neither peak pharyngeal pressure nor incoordination were predictors of outcome. In pharyngeal dysphagia, hypopharyngeal intrabolus pressure, and not peak pharyngeal pressure, is a predictor of response to cricopharyngeal disruption. The relationship between intrabolus pressure and impaired sphincter opening is an indirect measure of sphincter compliance which helps predict therapeutic response.

Mechanisms of oral-pharyngeal dysphagia in patients with Parkinson's disease

BACKGROUND & AIMS

Oral-pharyngeal dysphagia in Parkinson's disease is well recognized. The aim of this study was to establish the mechanisms of oral-pharyngeal dysphagia in these patients.

METHODS

Using simultaneous videoradiography and pharyngeal manometry, we studied 19 patients with Parkinson's disease (12 with oral-pharyngeal dysphagia and 7 without oral-pharyngeal dysphagia) and compared them with 23 healthy controls.

RESULTS

the clinical severity of Parkinson's disease predicted neither the presence nor the severity of dysphagia. Minor alterations in oral function were common in controls and patients, but pharyngeal dysfunction was significantly more prevalent in patients. Incomplete upper esophageal sphincter (UES) relaxation was present in 4 patients (21%), all of whom showed increased hypopharyngeal intrabolus pressure, but not all of whom had a diminished UES opening. The patients had a reduced UES diameter (P = 0.004) and a higher intrabolus pressure compared with the controls (P = 0.007). Pharyngeal contraction pressures were lower in patients, but 6 patients with dysphagia and an abnormal pharyngeal wall motion had normal peak pressures.

CONCLUSIONS

An incomplete UES relaxation and a reduced UES opening, both associated with high intrabolus pressure, are prevalent in Parkinson's disease. Oral-pharyngeal dysphagia in Parkinson's disease is multifactorial, with the majority of patients showing oral and pharyngeal dysfunction, even before the clinical expression of dysphagia. Impaired pharyngeal bolus transport is the major determinant of dysphagia.

Influence of cold stimulation on the normal pharyngeal swallow response

We examined the potential influence of cold stimulation of the anterior tonsillar pillars, before and after topical anesthesia, on the temporal linkage between the oral and pharyngeal components of the swallow. We hypothesized that if elicitation of the pharyngeal swallow were dependent upon stimulation of faucial mucosal receptors this response would be facilitated by cold tactile stimulation and inhibited by topical anesthesia. In 14 healthy volunteers undergoing simultaneous videoradiography and manometry we measured and compared regional transit and clearance times, and the timing of hyoid motion, upper esophageal sphincter relaxation, and opening within the swallow sequence. There was a significant, volume-dependent forward shift in timings of hyoid motion, upper esophageal sphincter (UES) relaxation profile, and opening which were influenced neither by cold stimulation nor topical anesthesia. Regional transit and clearance times and UES coordination were not influenced by cold stimulation. Pharyngeal clearance time was prolonged by tonsillar pillar anesthesia due to earlier arrival of the bolus head at this region (p = 0.002). We conclude that the normal pharyngeal swallow response is neither facilitated nor inhibited by prior cold tactile stimulation or topical anesthesia to the tonsillar pillars, respectively. These observations do not support the hypothesis that elicitation of the pharyngeal swallow response is dependent upon stimulation of mucosal receptors in the tonsillar arches.

Influence of mucosal receptors on deglutitive regulation of pharyngeal and upper esophageal sphincter function

The potential influence of mucosal sensory receptors on the regulation of oral-pharyngeal swallow events was studied in 15 healthy volunteers using simultaneous videoradiography and manometry. We determined the effects of selective pharyngeal and oral plus pharyngeal anesthesia on the following temporal and manometric measures in response to liquid and viscous swallows: regional transit and clearance times; motion of hyoid and larynx; upper esophageal sphincter relaxation, opening, and closure; and pharyngeal contraction wave characteristics. Under the influence of mucosal anesthesia no subjects demonstrated aspiration during deglutition. Neither regional transit and clearance times nor pharyngosphincteric coordination was influenced significantly by pharyngeal mucosal anesthesia or oral plus pharyngeal anesthesia. Although midpharyngeal and distal pharyngeal contraction amplitudes were not influenced by mucosal anesthesia, midpharyngeal contraction wave duration was reduced significantly by both pharyngeal (P = 0.02) and oral plus pharyngeal anesthesia (P = 0.0005). We conclude that 1) neither elicitation of the pharyngeal swallow response nor temporal regulation among swallow events is dependent on mucosal sensory receptors and 2) duration of the pharyngeal contraction is influenced by sensory input from the oral-pharyngeal mucosa.

Expediting the early hospital care of the adult patient with nontraumatic chest pain: impact of a modified ED triage protocol

A prospective study that compared a traditional emergency department (ED) triage protocol with an expedited protocol was conducted to determine if minimizing the subjectivity of nursing triage would result in more efficient management of adult patients presenting with nontraumatic chest pain. The traditional protocol triaged 382 patients into 1 of 5 categories of acuity. The expedited study group (418 patients) were triaged as usual but subsequently were treated as if they were triage category 1 or 2 (medical evaluation within 15 minutes of arrival). Traditional triage led to 40% of acute myocardial infarction (AMI) patients being triaged into inappropriately low-acuity categories. The expedited protocol resulted in significant improvement in the following intervals: ED arrival to triage, triage to cubicle, ED arrival to cubicle, ED arrival to electrocardiogram (ECG) ordered, ED arrival to ECG available, ED arrival to physician evaluation, and ED arrival to decision to thrombolyse. Study patients with non-AMI cardiac chest pain and AMI cardiac chest pain were evaluated by a physician an average of 12 minutes and 8 minutes after ED arrival, respectively. Delays in interdepartmental processes, such as ECG-technician responsiveness, thrombolysis protocol fulfillment and thrombolytic agent delivery, negated benefits derived from improvements in internal processes. Effective coordination of the numerous processes involved in the initial ED management of adult patients with nontraumatic chest pain is required to make thrombolytic therapy for AMI within 30 minutes of patient arrival a routinely achievable goal.

Relevant factors in the identification of hearing loss

This study examined factors which may affect early identification of hearing loss. The medical records of 123 children with educationally significant hearing impairment were examined. Information about each child's degree and type of hearing loss, etiology, referral source, birth and medical history, additional handicaps, age of suspicion of loss, mode of identification, age of identification, and age at which aided was entered into a database for further analysis. The age range for identification was 7 weeks to 10 yr, with a median age of 2.1 yr. Children with a greater degree of hearing loss, an additional handicap, additional medical conditions, or an etiology strongly associated with hearing loss were identified earlier than those without these factors. Unexpectedly, children with a history of middle ear dysfunction were identified no later than those without, and children with a positive family history of hearing loss were identified later than those with a negative family history. These results agree with other studies which show that, in general, children are identified and habilitated at a later age than that recommended by both the American Speech-Language-Hearing Association Committee and the Joint Committee on Infant Hearing.

Blunt aortic trauma: signs of high risk

In the last 10 years, our center has managed 60 cases of aortic rupture from blunt chest trauma. Nineteen patients died (32%), 11 of whom were moribund on admission. Two patients out of ten who had undergone aortography at other institutions arrived at our hospital with massive bleeding in the left chest and died despite immediate operation. Six patients exsanguinated 1 to 2 1/2 hours after admission while aortography was being arranged or performed, and review of these cases to identify clinical signs of high risk revealed that left hemothorax, pseudocoarctation, and/or supraclavicular hematoma were present in five of the six. It appeared that the survival rate of patients suspected of blunt aortic trauma who had any of these clinical signs might be improved if they were taken directly to the operating room. To investigate this possibility we reviewed all cases from the past 10 years (excluding patients moribund on arrival or who had aortography elsewhere) in whom suspicion of aortic trauma led to aortography or surgery. Thirteen of the 17 patients (76%) with one or more signs of high risk had torn the aortic isthmus, compared to 26 of 154 patients (17%) without these signs. Five of the high-risk group (29%) exsanguinated, compared to one (less than 1%) of the others. No patient in this series died from unsuspected aortic trauma, which we attribute to the liberal use of aortography. Except for the patients with exsanguinating hemorrhage preoperatively, there were no operative or postoperative deaths.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatic vein bullet embolus as a complication of left thoracic gunshot injury

The case of a patient with a hepatic vein bullet embolus complicating a left ventricular gunshot injury is described. The patient presented hypotensive with a left midaxillary entrance wound. Initial radiographs showed a bullet fragment below the right hemidiaphragm. Emergency open thoracotomy was performed with release of a tense pericardial effusion and repair of a left ventricular penetrating wound. Surgical exploration failed to reveal direct penetrating injury to the diaphragm or abdominal viscera. After a hepatic venogram localized the bullet fragment in a branch of the right lobe hepatic vein, a periscopically directed catheter extraction of the fragment was successfully performed. A discussion of missile embolization, its pathology, clinical presentation, diagnosis, and management is presented.