Development of an Automated Ultrasound Signal Indicator of Lung Interstitial Syndrome.

OBJECTIVES: The number and distribution of lung ultrasound (LUS) imaging artifacts termed B-lines correlate with the presence of acute lung disease such as infection, acute respiratory distress syndrome (ARDS), and pulmonary edema. Detection and interpretation of B-lines require dedicated training and is machine and operator-dependent. The goal of this study was to identify radio frequency (RF) signal features associated with B-lines in a cohort of patients with cardiogenic pulmonary edema. A quantitative signal indicator could then be used in a single-element, non-imaging, wearable, automated lung ultrasound sensor (LUSS) for continuous hands-free monitoring of lung fluid. METHODS: In this prospective study a 10-zone LUS exam was performed in 16 participants, including 12 patients admitted with acute cardiogenic pulmonary edema (mean age 60 ± 12 years) and 4 healthy controls (mean age 44 ± 21). Overall,160 individual LUS video clips were recorded. The LUS exams were performed with a phased array probe driven by an open-platform ultrasound system with simultaneous RF signal collection. RF data were analyzed offline for candidate B-line indicators based on signal amplitude, temporal variability, and frequency spectrum; blinded independent review of LUS images for the presence or absence of B-lines served as ground truth. Predictive performance of the signal indicators was determined with receiving operator characteristic (ROC) analysis with k-fold cross-validation. RESULTS: Two RF signal features-temporal variability of signal amplitude at large depths and at the pleural line-were strongly associated with B-line presence. The sensitivity and specificity of a combinatorial indicator were 93.2 and 58.5%, respectively, with cross-validated area under the ROC curve (AUC) of 0.91 (95% CI = 0.80-0.94). CONCLUSION: A combinatorial signal indicator for use with single-element non-imaging LUSS was developed to facilitate continuous monitoring of lung fluid in patients with respiratory illness.

Impact of an Institutional Clinical Pathway on Emergency Physicians' Stated Preferences in Treating Patients with Low-Risk Pulmonary Embolism.

BACKGROUND: Evidence continues to accumulate that select patients with acute low-risk pulmonary embolism (PE) can be safely discharged from the emergency department. Despite this, outpatient management continues to be uncommon. We report changes in emergency providers' stated preferences on low-risk acute PE management before and after the development and implementation of an institutional clinical pathway and decision tool. METHODS: We performed an observational analysis of attending emergency physicians' stated preferences towards the management of low-risk acute PE using survey results before and after the development and implementation of an electronic health record-embedded institutional low-risk acute PE pathway. RESULTS: Attending emergency medicine providers reported feeling more comfortable using PE risk stratification scores to identify dischargeable low-risk PE patients and also reported that they would be more likely to discharge a hypothetical patient with low-risk acute PE. CONCLUSION: Our results suggest that the implementation of an institutional clinical pathway with integration into the electronic health record was associated with a change in emergency physicians' stated preferences for managing patients with acute low-risk PE in the emergency department. Implementation of an evidence-based standard pathway was associated with increased comfort and familiarity with PE risk stratification, and an increased comfort with and preference for early outpatient management of low-risk PE.

First Series Using Ultrasonic Propulsion and Burst Wave Lithotripsy to Treat Ureteral Stones.

PURPOSE: Our goal was to test transcutaneous focused ultrasound in the form of ultrasonic propulsion and burst wave lithotripsy to reposition ureteral stones and facilitate passage in awake subjects. MATERIALS AND METHODS: Adult subjects with a diagnosed proximal or distal ureteral stone were prospectively recruited. Ultrasonic propulsion alone or with burst wave lithotripsy was administered by a handheld transducer to awake, unanesthetized subjects. Efficacy outcomes included stone motion, stone passage, and pain relief. Safety outcome was the reporting of associated anticipated or adverse events. RESULTS: Twenty-nine subjects received either ultrasonic propulsion alone (n = 16) or with burst wave lithotripsy bursts (n = 13), and stone motion was observed in 19 (66%). The stone passed in 18 (86%) of the 21 distal ureteral stone cases with at least 2 weeks follow-up in an average of 3.9±4.9 days post-procedure. Fragmentation was observed in 7 of the burst wave lithotripsy cases. All subjects tolerated the procedure with average pain scores (0-10) dropping from 2.1±2.3 to 1.6±2.0 (P = .03). Anticipated events were limited to hematuria on initial urination post-procedure and mild pain. In total, 7 subjects had associated discomfort with only 2.2% (18 of 820) propulsion bursts. CONCLUSIONS: This study supports the efficacy and safety of using ultrasonic propulsion and burst wave lithotripsy in awake subjects to reposition and break ureteral stones to relieve pain and facilitate passage.

Transfer Patient Imaging: Assessment of the Impact of Discrepancies Identified by Emergency Radiologists.

PURPOSE: Advanced imaging examinations of emergently transferred patients (ETPs) are overread to various degrees by receiving institutions. The practical clinical impact of these second opinions has not been studied in the past. The purpose of this study is to determine if emergency radiology overreads change emergency medicine decision making on ETPs in the emergency department (ED). METHODS: All CT and MRI examinations on patients transferred to a level I trauma center during calendar year 2018 were routinely overread by emergency radiologists and discrepancies with the outside report electronically flagged. All discrepant reports compared with the outside interpretations were reviewed by one of four emergency medicine physicians. Comparing the original and final reports, reviewers identified changes in patient management that could be attributed to the additional information contained in the final report. Changes in patient care were categorized as affecting ED management, disposition, follow-up, or consulting services. RESULTS: Over a 12-month period, 5,834 patients were accepted in transfer. Among 5,631 CT or MRI examinations with outside reports available, 669 examinations (12%) had at least one discrepancy in the corresponding outside report. In 219 examinations (33%), ED management was changed by discrepancies noted on the final report; patient disposition was affected in 84 (13%), outpatient follow-up in 54 (8%), and selection of consulting services in 411 (61%), and ED stay was extended in 544 (81%). Discrepant findings affected decision making in 613 of 669 of examinations (92%). CONCLUSION: Emergency radiology overreading of transferred patients' advanced imaging examinations provided actionable additional information to emergency medicine physicians in the care of 613 of 669 (92%) examinations with discrepant findings. This added value is worth the effort to design workflows to routinely overread CT and MRI examinations of ETPs.

Strategies to Optimize Nephrolithiasis Emergency Care (STONE): Prospective Evaluation of an Emergency Department Clinical Pathway.

OBJECTIVE: To convene a multi-disciplinary panel to develop a pathway for Emergency Department (ED) patients with suspected nephrolithiasis and then prospectively evaluate its effect on patient care. MATERIALS AND METHODS: The STONE Pathway was developed and linked to order sets within our Electronic Health Record in April 2019. Records were prospectively reviewed for ED patients who underwent ultrasound or Computerized Tomography (CT) to evaluate suspected nephrolithiasis between January 2019 and August 2019 within our institution. The primary outcome measure was the proportion of patients whose ED CT was low dose (<4 mSv). Secondary outcome measures included receipt of pathway-concordant pain medications and urine strainers. Order set utilization was evaluated as a process measure. Balance measures assessed included repeat ED visits, imaging, hospitalizations, and a urologic clinic visit or surgery within 30 days of discharge. RESULTS: 441 patients underwent ED imaging, of whom 261 (59%) were evaluated for suspected nephrolithiasis. The STONE Pathway was used in 50 (30%) eligible patients. Patients treated with the Pathway were more likely to undergo low-dose CTs (49% vs 23%, P <.001), and receive guideline-concordant pain medications such as NSAIDs (90% vs 62%, P <.001), and were less likely to return to the ED within 30 days (13% vs 2%, P = .01). These measures demonstrated special cause variation following Pathway release. CONCLUSION: Clinical pathways increase compliance with evidence-based practices for pain control and imaging in nephrolithiasis emergency care and may improve the delivery of value-based care.

Assessing lactate concentration as a predictor of 28-day in-hospital mortality in the presence of ethanol: A retrospective study of emergency department patients.

BACKGROUND: Presence of ethanol (EtOH) may alter the relationship between blood lactate concentrations and mortality. This study compares lactate-associated mortality risk in the presence and absence of EtOH. METHODS: We performed a retrospective cohort study including all patients, age >17 years, presenting from January 2012-December 2018, to an urban, academic emergency department, with a clinically measured lactate. Data were electronically abstracted from the medical record. The primary outcome was 28-day in-hospital mortality. Patients were grouped by EtOH test results as follows: 1) present (any EtOH detected), 2) absent (EtOH concentration measured and not detected), or 3) not ordered. Marginal analysis was used to calculated probability of mortality for fixed values of lactate and model covariates. RESULTS: Of 40,956 adult emergency department patients with measured lactate, we excluded 768 (1.89%) for lactate >10.0 mmol/L, leaving 40,240 for analysis: 4,066 (10.1%) EtOH present, 10,819 (26.9%) EtOH absent, 25,355 (63%) EtOH not ordered. Of these, 1790 (4.4%) had 28-day in-hospital mortality. Marginal probability of mortality calculated for specific lactate values found less risk for EtOH Present patients versus EtOH absent patients at lactate 0.0 mmol/L (0.8% [95%CI: 0.5-1.2%] vs 3.2% [2.8-3.6%]), 2.0 mmol/L (1.5% [1.1-1.9%] vs 4.0% [3.7-4.3%]), 4.0 mmol/L (2.6% [2.2-3.1%] vs 5.0% [4.6-5.4%]), until 6.0 mmol/L (4.5% [3.7-5.4%] vs 6.2% [5.4-7.0%]). CONCLUSION: EtOH presence significantly alters lactate-associated mortality risk when lactate <6.0 mmol/L. Emergency department clinicians should interpret these lactate values with caution and consider other data for risk stratification when EtOH is present.

In-Office Ultrasound Facilitates Timely Clinical Care at a Multidisciplinary Kidney Stone Center.

INTRODUCTION: A considerable publication record exists comparing sensitivity and specificity of radiological ultrasound (including point of care ultrasound) to computerized tomography for stone disease. However, the practical application of in-office ultrasound to support the growing number of kidney stone centers around the world represents a nuanced topic that is ripe for study and discussion. METHODS: We provide a descriptive analysis of how in-office ultrasound is being used as an adjunct to clinical care based on our experience during 50 days in clinic at an institutionally affiliated, multidisciplinary kidney stone center. Clinic subjects gave consent and underwent ultrasound as part of research studies. Ultrasonograms were shared with and verified by the treating physician before the patient was discharged from care. We counted the number of times research imaging altered the care plan. RESULTS: Of the 60 patients enrolled the clinician used the information obtained from the studies in 20 (33%) to determine the course of clinical care that resulted in a change in treatment or process. CONCLUSIONS: Ultrasound has the potential to be a cost-effective and valuable tool that can provide more efficient workflow within a kidney stone center or urology clinic.

Pearl-unjammed: the Seattle stone maneuver for ureteropelvic junction urolithiasis.

Renal colic encounters are common; in the United States alone, they represent greater than one million annual emergency department (ED) visits. Most of these stones are managed conservatively with a trial of passage. However, some lead to repeat colic episodes, secondary ED visits, increased anxiety, and increased cost. Of the 5%-10% of symptomatic stones that become lodged at the ureteropelvic junction and are larger than 5 mm, most require operative intervention. In the process of executing a NASA-funded study of ultrasonic repositioning of kidney stones, the subject was administered fluid to dilate the collecting system, placed in Trendelenburg bed positioning, and rolled to both sides. During this process a symptomatic, obstructing 9-mm ureteropelvic junction stone moved back into the kidney's lower pole/infundibulum and symptoms were immediately resolved. The patient remained asymptomatic for a period of 5 weeks at which point elective intervention was scheduled. This case demonstrates that ureteropelvic junction stones may be repositioned in a non-invasive manner, turning a stone that requires urgent intervention into one that can be managed electively.

Trends in Diagnostic Point-of-Care Ultrasonography Reimbursement for Medicare Beneficiaries Among the US Emergency Medicine Workforce, 2012 to 2016.

STUDY OBJECTIVE: Point-of-care ultrasonography allows rapid diagnosis in the emergency department. A previous study found that a low prevalence of emergency medicine clinicians received point-of-care ultrasonography reimbursement in 2012 (0.7%). We determine nationwide point-of-care ultrasonography reimbursement patterns for 4 subsequent years. METHODS: We performed a cross-sectional study using 2012 to 2016 data from the Centers for Medicare & Medicaid Fee-for-Service Provider Utilization and Payment Data Part B, defining point-of-care ultrasonographic examinations using Current Procedural Terminology codes. The emergency medicine workforce was defined by emergency medicine, family medicine, internal medicine, critical care, and advanced practice providers who received emergency medicine-specific reimbursements. We compared patterns of point-of-care ultrasonography reimbursement among emergency physicians in 2012 versus 2016 through a 2-sample test of proportions. RESULTS: In 2012, 342 (0.7% of total) emergency medicine workforce clinicians were reimbursed for diagnostic point-of-care ultrasonography versus 801 (1.3%) in 2016. Emergency physicians represented an increasing proportion of the total workforce, increasing from 86.0% (95% confidence interval 82.3% to 89.6%) in 2012 (N=294) to 94.6% (95% confidence interval 93.1% to 96.2%) in 2016 (N=758). From 2012 to 2016, total point-of-care ultrasonography reimbursements increased from 13,697 to 31,717, with significant growth from echocardiograms (4,127 to 14,978), abdominal examinations (3,682 to 7,140), and thoracic examinations (801 to 5,278). CONCLUSION: The proportion of emergency medicine workforce clinicians receiving diagnostic point-of-care ultrasonography reimbursements, as well as the number of point-of-care ultrasonographic studies, more than doubled from 2012 to 2016. Efforts are needed to understand barriers to adoption of point-of-care ultrasonography because only a small proportion of the emergency medicine clinician workforce was reimbursed in any year.

Interleukin-6 improves infection identification when added to physician judgment during evaluation of potentially septic patients.

BACKGROUND: Identifying infection is critical in early sepsis screening. This study assessed whether biomarkers of endothelial activation and/or inflammation could improve identification of infection among Emergency Department (ED) patients with organ dysfunction. METHODS: We performed a prospective, observational study at two urban, academic EDs, between June 2016 and December 2017. We included admitted adults with 1) two systemic inflammatory response syndrome criteria and organ dysfunction, 2) systolic blood pressure < 90 mmHg, or 3) lactate ≥4.0 mmol/L. We excluded patients with trauma, transferred for intracranial hemorrhage, or without available blood samples. Treating ED physicians reported presence of infection (yes/no) at inpatient admission. Assays for angiopoietin-1, angiopoietin-2, soluble tumor necrosis factor receptor-1, interleukin-6, and interleukin-8 were performed using ED blood samples. The primary outcome was infection, adjudicated by paired physician review. Using logistic regression, we compared the performance of physician judgment, biomarkers, and physician judgment-biomarkers combination to predict infection. Area under the curve (AUC) and AUC 95% confidence intervals were estimated by bootstrap procedure. RESULTS: Of 421 patients enrolled, 306 patients met final study criteria. Of these, 154(50.3%) patients had infectious etiologies. Physicians correctly discriminated infectious from non-infectious etiologies in 239 (78.1%). Physician judgment performed moderately when discriminating infection (AUC 0.78, 95% CI: 0.74-0.82) and outperformed the best biomarker model, interleukin-6 alone, (AUC 0.71, 0.66-0.76). Physician judgment improved when including interleukin-6 (AUC 0.84, 0.79-0.87), with modest AUC improvement: 0.06 (0.03-0.08). CONCLUSIONS: In ED patients with organ dysfunction, plasma interleukin-6 may improve infection discrimination when added to physician judgment.

Predicting Prolonged Intensive Care Unit Stay Among Patients With Sepsis-Induced Hypotension.

BACKGROUND: Sepsis risk stratification tools typically predict mortality, although stays in the intensive care unit (ICU) of 24 hours or longer may be more clinically relevant for emergency department disposition. OBJECTIVE: To explore predictors of ICU stay of 24 hours or longer among infected, hypotensive emergency department patients. METHODS: A secondary analysis of 2 prospective, observational studies of adult patients with severe sepsis or an infection with a systolic blood pressure less than 90 mm Hg in 3 urban, academic emergency departments was performed. Patients with hypotension and infection were included. Patients with emergency department intubation, vasopressor administration, and/or death were excluded. The primary outcome was ICU stay of 24 hours or longer or death in less than 24 hours. Multivariable logistic regression was used to predict ICU stay of 24 hours or longer. RESULTS: Of 233 patients, 108 (46.4%) had ICU stays of 24 hours or longer. History of heart failure (odds ratio, 3.6; 95% CI, 1.5-8.3), bicarbonate level less than 20 mEq/L (odds ratio, 2.0; 95% CI, 1.1-3.8), respiratory rate greater than 20/min (odds ratio, 2.0; 95% CI, 1.1-3.7), and creatinine level greater than 2.0 mg/dL (odds ratio, 3.6; 95% CI, 1.9-6.7) were independent predictors of ICU stay of 24 hours or longer (area under curve, 0.74). The presence of 1 of these factors predicted ICU stay of 24 hours or longer (area under curve, 0.74) with 82.4% sensitivity and 49.6% specificity. CONCLUSIONS: These exploratory results show that heart failure, bicarbonate level of less than 20 mEq/L, tachypnea, or creatinine level greater than 2.0 mg/dL increases the likelihood of an ICU stay of 24 hours or longer among infected, hypotensive emergency department patients.

Recognising Bias in Studies of Diagnostic Tests Part 1: Patient Selection.

In this two-part series on sources of bias in studies of diagnostic test performance, we outline common errors and optimal conditions during three study phases: patient selection, interpretation of the index test and disease verification by a gold standard. Here in part 1, biases associated with suboptimal participant selection are discussed through the lens of partial verification bias and spectrum bias, both of which increase the proportion of participants who are the 'sickest of the sick' or the 'wellest of the well.' Especially through retrospective methodology, partial verification introduces bias by including patients who are test positive by a gold standard, since patients with a positive index test are more likely to go on to further gold standard testing. Spectrum bias is frequently introduced through case-control design, dropping of indeterminate results or convenience sampling. After reading part 1, the informed clinician should be better able to judge the quality of a diagnostic test study, its inherent limitations and whether its results could be generalisable to their practice. Part 2 will describe how interpretation of the index test and disease verification by a gold standard can contribute to diagnostic test bias.

Recognising bias in studies of diagnostic tests part 2: interpreting and verifying the index test.

Multiple pitfalls can occur with the conduct and analysis of a study of diagnostic tests, resulting in biased accuracy. Our conceptual model includes three stages: patient selection, interpretation of the index test and disease verification. In part 2, we focus on (1) Interpretation bias (or workup bias): where the classification of an indeterminate index test result can bias the accuracy of a test or how lack of blinding can bias a subjective test result, and (2) Disease verification bias: where the index test result is incorporated into the gold standard or when the gold standard is applied only to a select population as the gold standard is an invasive test. In an example with age-adjusted D-dimer for pulmonary embolism, differential verification bias was a limitation due to the use of two gold standards-CT for a high-risk population and follow-up for symptoms in a low-risk population. However, there are circumstances when certain choices in study design are unavoidable, and result in biased test characteristics. In this case, the informed reader will better judge the quality of a study by recognising the potential biases and limitations by being methodical in their approach to understanding the methods, and in turn, better apply studies of diagnostic tests into their clinical practice.

Postdischarge Unplanned Care Events Among Commercially Insured Patients With an Observation Stay Versus Short Inpatient Admission.

STUDY OBJECTIVE: Observation stays are composing an increasing proportion of unscheduled hospitalizations in the United States, with unclear consequences for the quality of care. This study used a nationally representative data set of commercially insured patients hospitalized from the emergency department (ED) to compare 30-day postdischarge unplanned care events after an observation stay versus a short inpatient admission. METHODS: This was a retrospective analysis of ED hospitalizations using the 2015 Truven MarketScan Commercial Claims and Encounters data set. Adult observation stays and short inpatient hospitalizations of 2 days or less were identified and followed for 30 days from hospital discharge to identify unplanned care events, defined as a subsequent inpatient admission, observation stay, or return ED visit. A propensity score analysis was used to compare rates of unplanned events after each type of index hospitalization. RESULTS: Among the propensity-weighted cohorts, patients with an index observation stay were 28% more likely to experience any unplanned care event within 30 days of discharge compared with those with a short inpatient admission (20.4% versus 15.9%; risk ratio 1.28; 95% confidence interval [CI] 1.21 to 1.34). Specifically, patients in the observation stay group had substantially higher rates of postdischarge observation stays (4.8% versus 1.9%; odds ratio 2.60; 95% CI 2.15 to 3.16) and ED revisits with discharge (11.1% versus 8.8%; odds ratio 1.26; 95% CI 1.21 to 1.44) compared with those in the inpatient group, but were less likely to be readmitted as inpatients (6.4% versus 7.2%; odds ratio 0.90; 95% CI 0.83 to 0.96). CONCLUSION: Commercially insured patients with an observation stay from the ED have a higher risk of postdischarge acute care events compared with similar patients with a short inpatient admission. Additional research is necessary to determine the extent to which quality of care, including care transitions, may differ between these 2 groups.

Clozapine Intoxication Mimicking Acute Stroke.

Clozapine is an atypical antipsychotic drug prescribed for treatment-resistant schizophrenia. The risk of adverse hematologic, cardiovascular, and neurologic effects has tempered its use, and reports of overdoses remain rare. We report a case of accidental acute clozapine intoxication in a clozapine-naïve patient, who presented with symptoms mimicking acute stroke and later developed status epilepticus. Clozapine intoxication is a rare presentation in the emergency department with potential for iatrogenic harm if not correctly identified.

State of the National Emergency Department Workforce: Who Provides Care Where?

STUDY OBJECTIVE: We describe the current US emergency medicine workforce in terms of clinician type and examine rural and urban emergency medicine workforce differences. METHODS: Using the 2014 Medicare Public Use Files, we performed a cross-sectional study of all clinicians receiving reimbursement for evaluation and management (E/M) services (levels 1 to 5) to Medicare fee-for-service Part B beneficiaries in the emergency department. Providers were defined as emergency physicians, nonemergency physicians, or advanced practice providers, corresponding with the Medicare Public Use Files data set. The primary outcome was the number of clinicians providing greater than 10 E/M claims tabulated as a distinct encounter. Urbanicity data were obtained from the National Bureau of Economic Research. RESULTS: Of 58,641 unique emergency medicine clinicians, 35,856 (61.1%) were classified as emergency physicians, 8,397 (14.3%) as nonemergency physicians, and 14,360 (24.5%) as advanced practice providers. Among nonemergency physicians categorized as emergency medicine clinicians, family practice and internal medicine predominated (41.7% and 19.9%, respectively). Among advanced practice providers, physician assistants (68.4%) and nurse practitioners (31.5%) predominated. A total of 58,565 emergency medicine clinicians were mapped to 2,291 US counties or equivalents. Urban counties had a higher proportion of emergency physicians (63.9%) compared with rural counties (44.8%); 27.1% of counties had no emergency medicine clinicians and 41.4% of counties had no emergency physicians reimbursed by Medicare fee-for-service Part B. CONCLUSION: This work establishes a new baseline estimate of the emergency care workforce, encompassing nearly 60,000 emergency medicine clinicians, of whom fewer than 2 in 3 were emergency physicians. Notable differences exist in the type of clinician staffing of emergency care between urban and rural communities.

The cost of observation care for commercially insured patients visiting the emergency department.

OBJECTIVE: To examine trends in the use of ED observation stays among a national sample of patients with commercial insurance, and assess the patient cost-burden of an observation stay relative to an short inpatient hospitalization from the ED. METHODS: Retrospective analysis of ED observation stays and inpatient hospitalizations from 2008 to 2015 using the Truven MarketScan® Commercial Claims and Encounters database. Index ED visits were identified from claims files and assessed for evidence of an observation or inpatient hospitalization. Total and out-of-pocket costs were calculated for the index hospitalization and a 30-day episode of care and standardized to 2015 $USD. Costs for ED patients with an observation stay were compared to a similar, propensity-matched cohort of ED patients hospitalized as inpatients. RESULTS: Over the 8 year period, observation stay admissions increased from 4.3% to 6.8% of total ED visits (60.5% relative increase) while inpatient admissions fell from 10.8% to 8.9% (16.6% relative decrease). In 2015, the mean total cost was $8162 for an observation stay and $22,865 for an inpatient hospitalization. Patient out-of-pocket costs were $962 and $1403, respectively. Among the propensity-matched cohorts, relative mean costs for the index hospitalization were 41% higher and patient out-of-pocket costs were 33% higher if the patient was admitted as an inpatient from the ED versus observation during their hospitalization. CONCLUSIONS: Observation hospitalizations are an increasingly common disposition for patients entering the hospital through the ED. Both total and patient out-of-pocket costs are lower, on average, for an observation stay compared with a similar inpatient admission for ED patients requiring hospitalization.

Imaging Strategies for Suspected Acute Cranial Shunt Failure: A Cost-Effectiveness Analysis.

OBJECTIVES: We compared cost-effectiveness of cranial computed tomography (CT), fast sequence magnetic resonance imaging (fsMRI), and ultrasonography measurement of optic nerve sheath diameter (ONSD) for suspected acute shunt failure from the perspective of a health care organization. METHODS: We modeled 4 diagnostic imaging strategies: (1) CT scan, (2) fsMRI, (3) screening ONSD by using point of care ultrasound (POCUS) first, combined with CT, and (4) screening ONSD by using POCUS first, combined with fsMRI. All patients received an initial plain radiographic shunt series (SS). Short- and long-term costs of radiation-induced cancer were assessed with a Markov model. Effectiveness was measured as quality-adjusted life-years. Utilities and inputs for clinical variables were obtained from published literature. Sensitivity analyses were performed to evaluate the effects of parameter uncertainty. RESULTS: At a previous probability of shunt failure of 30%, a screening POCUS in patients with a normal SS was the most cost-effective. For children with abnormal SS or ONSD measurement, fsMRI was the preferred option over CT. Performing fsMRI on all patients would cost $269 770 to gain 1 additional quality-adjusted life-year compared with POCUS. An imaging pathway that involves CT alone was dominated by ONSD and fsMRI because it was more expensive and less effective. CONCLUSIONS: In children with low pretest probability of cranial shunt failure, an ultrasonographic measurement of ONSD is the preferred initial screening test. fsMRI is the more cost-effective, definitive imaging test when compared with cranial CT.

Derivation of decision rules to predict clinically important outcomes in acute flank pain patients.

OBJECTIVE: Routine CT for patients with acute flank pain has not been shown to improve patient outcomes, and it may unnecessarily expose patients to radiation and increased costs. As preliminary steps toward the development of a guideline for selective CT, we sought to determine the prevalence of clinically important outcomes in patients with acute flank pain and derive preliminary decision rules. METHODS: We analyzed data from a randomized trial of CT vs. ultrasonography for patients with acute flank pain from 15 EDs between October 2011 and February 2013. Clinically important outcomes were defined as inpatient admission for ureteral stones and alternative diagnoses. Clinically important stones were defined as stones requiring urologic intervention. We sought to derive highly sensitive decision rules for both outcomes. RESULTS: Of 2759 participants, 236 (8.6%) had a clinically important outcome and 143 (5.2%) had a clinically important stone. A CDR including anemia (hemoglobin <13.2g/dl), WBC count >11000/µl, age>42years, and the absence of CVAT had a sensitivity of 97.9% (95% CI 94.8-99.2%) and specificity of 18.7% (95% 17.2-20.2%) for clinically important outcome. A CDR including hydronephrosis, prior history of stone, and WBC count <8300/µl had a sensitivity of 98.6% (95% CI 94.5-99.7%) and specificity of 26.0% (95% 24.2-27.7%) for clinically important stone. CONCLUSIONS: We determined the prevalence of clinically important outcomes in patients with acute flank pain, and derived preliminary high sensitivity CDRs that predict them. Validation of CDRs with similar test characteristics would require prospective enrollment of 2100 patients.