Impact of point-of-care ultrasonography on ED time to disposition for patients with nontraumatic shock.

STUDY OBJECTIVE: Nontraumatic shock in the emergency department (ED) has multiple causes and carries in-hospital mortality approaching 20%, underscoring the need for prompt diagnosis and treatment. Diagnostic ultrasonography at the point of care is one method that may improve the ability of ED physicians to quickly diagnose and treat. This study assesses the effect of the use and timing of point-of-care (POC) ultrasonography on time to disposition request. METHODS: This retrospective study across 4 Connecticut EDs compared propensity score matched shock patients who did and did not receive POC ultrasonography. Two propensity score matches were performed: the first using covariates of time to disposition from previous literature and the second using 25 novel covariates identified from electronic health records using machine learning to reduce variable selection biases. RESULTS: A total of 3834 unique patients presented with shock during an 18-month period, and 703 (18.3%) patients received POC ultrasonography. Mean time to disposition for all patients was 255.4minutes (interquartile range, 163.8). After propensity score matching, patients had a mean reduction of 26.7minutes (95% confidence interval [CI], 2.8-58.3) in time to disposition when POC ultrasonography was performed within 1hour of ED arrival and a lesser reduction of 16.7minutes (95% CI, -2.8 to 35.5) when POC ultrasonography was performed within 2hours. There was no evidence of reduction in time to disposition when ultrasonography was performed after 2hours (16.7minutes; 95% CI, -14.3 to 29.9). Propensity score models using machine learning-selected variables yielded similar results. CONCLUSION: Performance of POC ultrasonography likely improves time to disposition when performed early on ED patients with shock.

Ureteral Stones: Implementation of a Reduced-Dose CT Protocol in Patients in the Emergency Department with Moderate to High Likelihood of Calculi on the Basis of STONE Score.

Purpose To determine if a reduced-dose computed tomography (CT) protocol could effectively help to identify patients in the emergency department (ED) with moderate to high likelihood of calculi who would require urologic intervention within 90 days. Materials and Methods The study was approved by the institutional review board and written informed consent with HIPAA authorization was obtained. This was a prospective, single-center study of patients in the ED with moderate to high likelihood of ureteral stone undergoing CT imaging. Objective likelihood of ureteral stone was determined by using the previously derived and validated STONE clinical prediction rule, which includes five elements: sex, timing, origin, nausea, and erythrocytes. All patients with high STONE score (STONE score, 10-13) underwent reduced-dose CT, while those with moderate likelihood of ureteral stone (moderate STONE score, 6-9) underwent reduced-dose CT or standard CT based on clinician discretion. Patients were followed to 90 days after initial imaging for clinical course and for the primary outcome of any intervention. Statistics are primarily descriptive and are reported as percentages, sensitivities, and specificities with 95% confidence intervals. Results There were 264 participants enrolled and 165 reduced-dose CTs performed; of these participants, 108 underwent reduced-dose CT alone with complete follow-up. Overall, 46 of 264 (17.4%) of patients underwent urologic intervention, and 25 of 108 (23.1%) patients who underwent reduced-dose CT underwent a urologic intervention; all were correctly diagnosed on the clinical report of the reduced-dose CT (sensitivity, 100%; 95% confidence interval: 86.7%, 100%). The average dose-length product for all standard-dose CTs was 857 mGy · cm ± 395 compared with 101 mGy · cm ± 39 for all reduced-dose CTs (average dose reduction, 88.2%). There were five interventions for nonurologic causes, three of which were urgent and none of which were missed when reduced-dose CT was performed. Conclusion A CT protocol with over 85% dose reduction can be used in patients with moderate to high likelihood of ureteral stone to safely and effectively identify patients in the ED who will require urologic intervention. (©) RSNA, 2016 Online supplemental material is available for this article.

STONE PLUS: Evaluation of Emergency Department Patients With Suspected Renal Colic, Using a Clinical Prediction Tool Combined With Point-of-Care Limited Ultrasonography.

STUDY OBJECTIVE: We determine whether renal point-of-care limited ultrasonography (PLUS) used in conjunction with the Sex, Timing, Origin, Nausea, Erythrocytes (STONE) clinical prediction score can aid identification of emergency department (ED) patients with uncomplicated ureteral stone or need for urologic intervention. METHODS: This was a prospective observational study of adult ED patients undergoing computed tomography (CT) scan for suspected ureteral stone. The previously validated STONE score classifies patients into risk categories of low (≈10%), moderate (≈50%), or high (≈90%) for symptomatic stone. Renal PLUS assessed for presence of hydronephrosis before CT scanning. The primary outcomes of symptomatic ureteral stone or acutely important alternative finding were abstracted from CT reports. The secondary outcome, urologic intervention, was assessed by 90-day follow-up interview and record review. RESULTS: Of 835 enrolled patients, ureteral stone was identified in 53%, whereas 6.5% had an acutely important alternative finding on CT. Renal PLUS modestly increased sensitivity for symptomatic stone among low and moderate STONE score categories. Moderate or greater hydronephrosis improved specificity from 67% (62% to 72%) to 98% (93% to 99%) and 42% (37% to 47%) to 92% (86% to 95%) in low- and moderate-risk patients, with likelihood ratios of 22 (95% CI, 4.2-111) and 4.9 (95% CI, 2.9-8.3), respectively. Test characteristics among high-risk patients were unchanged by renal PLUS. For urologic intervention, any hydronephrosis was 66% sensitive (57% to 74%), whereas moderate or greater hydronephrosis was 86% specific overall (83% to 89%) and 81% (69% to 90%) sensitive and 79% 95% CI, (73-84) specific among patients with the highest likelihood of symptomatic stone. CONCLUSION: Hydronephrosis on renal PLUS modestly improved risk stratification in low- and moderate-risk STONE score patients. The presence or absence of hydronephrosis among high-risk patients did not significantly alter likelihood of symptomatic stone but may aid in identifying patients more likely to require urologic intervention.

Incidental findings on CT for suspected renal colic in emergency department patients: prevalence and types in 5,383 consecutive examinations.

PURPOSE: This study aimed to determine the prevalence, importance, and types of incidental findings (IF) in non-enhanced CT scans performed for suspected renal colic, based on ACR white papers and other accepted radiographic recommendations. METHODS: Retrospective review of 5,383 consecutive finalized reports of nonenhanced CT using renal colic protocol performed on adult patients at 2 emergency departments over a 5.5-year period. IF were defined as those unrelated to symptoms (as opposed to alternate causes of symptoms) and were categorized as "important" if follow-up was recommended based on recently published consensus recommendations. Subsets of reports of those with important IF were blindly re-reviewed to calculate inter-rater variability for presence and categorization of important IF. RESULTS: Important IF were identified in 12.7% (95% confidence interval [CI]: 11.8%-13.6%) of scans. Prevalence of important IF increased with age: important IF in individuals age >80 years were 4 times more common than for those aged 18-30 years: 28.9% (95% CI: 22.4%-36.4%) versus 6.9% (95% CI: 5.5%-8.6%), respectively, P ≤ .05. Women had a higher prevalence of important IF compared with men: 13.4% (95% CI: 12.2%-14.7%) versus 11.9% (95% CI: 10.7%-13.2%), but the difference was not statically significant (P = .09). There was substantial inter-rater agreement (kappa ≥ 0.69) regarding presence and classification of important IFs using published guidelines. CONCLUSIONS: Important IF occurred in 12.7% of non-enhanced CT scans performed for suspected renal colic in the emergency department and are more common in older individuals. Prospective studies that use radiographic recommendations to characterize IF and examine the outcome and cost of their workup are encouraged.

Accuracy of reduced-dose computed tomography for ureteral stones in emergency department patients.

STUDY OBJECTIVE: Reduced-dose computed tomography (CT) scans have been recommended for diagnosis of kidney stone but are rarely used in the emergency department (ED) setting. Test characteristics are incompletely characterized, particularly in obese patients. Our primary outcome is to determine the sensitivity and specificity of a reduced-dose CT protocol for symptomatic ureteral stones, particularly those large enough to require intervention, using a protocol stratified by patient size. METHODS: This was a prospective, blinded observational study of 201 patients at an academic medical center. Consenting subjects underwent both regular- and reduced-dose CT, stratified into a high and low body mass index (BMI) protocol based on effective abdominal diameter. Reduced-dose CT scans were interpreted by radiologists blinded to regular-dose interpretations. Follow-up for outcome and intervention was performed at 90 days. RESULTS: CT scans with both regular and reduced doses were conducted for 201 patients, with 63% receiving the high BMI reduced-dose protocol. Ureteral stone was identified in 102 patients (50.7%) of those receiving regular-dose CT, with a ureteral stone greater than 5 mm identified in 26 subjects (12.9%). Sensitivity of the reduced-dose CT for any ureteral stone was 90.2% (95% confidence interval [CI] 82.3% to 95.0%), with a specificity of 99.0% (95% CI 93.7% to 100.0%). For stones greater than 5 mm, sensitivity was 100% (95% CI 85.0% to 100.0%). Reduced-dose CT identified 96% of patients who required intervention for ureteral stone within 90 days. Mean reduction in size-specific dose estimate was 18.6 milligray (mGy), from 21.7 mGy (SD 9.7) to 3.4 mGy (SD 0.9). CONCLUSION: CT with substantial dose reduction was 90.2% (95% CI 82.3% to 95.0%) sensitive and 98.9% (95% CI 85.0% to 100.0%) specific for ureteral stones in ED patients with a wide range of BMIs. Reduced-dose CT was 96.0% (95% CI 80.5% to 99.3%) sensitive for ureteral stones requiring intervention within 90 days.

Effect of provider experience on clinician-performed ultrasonography for hydronephrosis in patients with suspected renal colic.

STUDY OBJECTIVE: Hydronephrosis is readily visible on ultrasonography and is a strong predictor of ureteral stones, but ultrasonography is a user-dependent technology and the test characteristics of clinician-performed ultrasonography for hydronephrosis are incompletely characterized, as is the effect of ultrasound fellowship training on predictive accuracy. We seek to determine the test characteristics of ultrasonography for detecting hydronephrosis when performed by clinicians with a wide range of experience under conditions of direct patient care. METHODS: This was a prospective study of patients presenting to an academic medical center emergency department with suspected renal colic. Before computed tomography (CT) results, an emergency clinician performed bedside ultrasonography, recording the presence and degree of hydronephrosis. CT data were abstracted from the dictated radiology report by an investigator blinded to the bedside ultrasonographic results. Test characteristics of bedside ultrasonography for hydronephrosis were calculated with the CT scan as the reference standard, with test characteristics compared by clinician experience stratified into 4 levels: attending physicians with emergency ultrasound fellowship training, attending physicians without emergency ultrasound fellowship training, ultrasound experienced non-attending physician clinicians (at least 2 weeks of ultrasound training), and ultrasound inexperienced non-attending physician clinicians (physician assistants, nurse practitioners, off-service rotators, and first-year emergency medicine residents with fewer than 2 weeks of ultrasound training). RESULTS: There were 670 interpretable bedside ultrasonographic tests performed by 144 unique clinicians, 80.9% of which were performed by clinicians directly involved in the care of the patient. On CT, 47.5% of all subjects had hydronephrosis and 47.0% had a ureteral stone. Among all clinicians, ultrasonography had a sensitivity of 72.6% (95% confidence interval [CI] 65.4% to 78.9%), specificity of 73.3% (95% CI 66.1% to 79.4%), positive likelihood ratio of 2.72 (95% CI 2.25 to 3.27), and negative likelihood ratio of 0.37 (95% CI 0.31 to 0.44) for hydronephrosis, using hydronephrosis on CT as the criterion standard. Among attending physicians with fellowship training, ultrasonography had sensitivity of 92.7% (95% CI 83.8% to 96.9%), positive likelihood ratio of 4.97 (95% CI 2.90 to 8.51), and negative likelihood ratio of 0.08 (95% CI 0.03 to 0.23). CONCLUSION: Overall, ultrasonography performed by emergency clinicians was moderately sensitive and specific for detection of hydronephrosis as seen on CT in patients with suspected renal colic. However, presence or absence of hydronephrosis as determined by emergency physicians with fellowship training in ultrasonography yielded more definitive test results. For clinicians without fellowship training, there was no significant difference between groups in the predictive accuracy of the application according to experience level.

Derivation and validation of a clinical prediction rule for uncomplicated ureteral stone--the STONE score: retrospective and prospective observational cohort studies.

OBJECTIVE: To derive and validate an objective clinical prediction rule for the presence of uncomplicated ureteral stones in patients eligible for computed tomography (CT). We hypothesized that patients with a high probability of ureteral stones would have a low probability of acutely important alternative findings. DESIGN: Retrospective observational derivation cohort; prospective observational validation cohort. SETTING: Urban tertiary care emergency department and suburban freestanding community emergency department. PARTICIPANTS: Adults undergoing non-contrast CT for suspected uncomplicated kidney stone. The derivation cohort comprised a random selection of patients undergoing CT between April 2005 and November 2010 (1040 patients); the validation cohort included consecutive prospectively enrolled patients from May 2011 to January 2013 (491 patients). MAIN OUTCOME MEASURES: In the derivation phase a priori factors potentially related to symptomatic ureteral stone were derived from the medical record blinded to the dictated CT report, which was separately categorized by diagnosis. Multivariate logistic regression was used to determine the top five factors associated with ureteral stone and these were assigned integer points to create a scoring system that was stratified into low, moderate, and high probability of ureteral stone. In the prospective phase this score was observationally derived blinded to CT results and compared with the prevalence of ureteral stone and important alternative causes of symptoms. RESULTS: The derivation sample included 1040 records, with five factors found to be most predictive of ureteral stone: male sex, short duration of pain, non-black race, presence of nausea or vomiting, and microscopic hematuria, yielding a score of 0-13 (the STONE score). Prospective validation was performed on 491 participants. In the derivation and validation cohorts ureteral stone was present in, respectively, 8.3% and 9.2% of the low probability (score 0-5) group, 51.6% and 51.3% of the moderate probability (score 6-9) group, and 89.6% and 88.6% of the high probability (score 10-13) group. In the high score group, acutely important alternative findings were present in 0.3% of the derivation cohort and 1.6% of the validation cohort. CONCLUSIONS: The STONE score reliably predicts the presence of uncomplicated ureteral stone and lower likelihood of acutely important alternative findings. Incorporation in future investigations may help to limit exposure to radiation and over-utilization of imaging. TRIAL REGISTRATION: www.clinicaltrials.gov NCT01352676.

Prevalence and clinical importance of alternative causes of symptoms using a renal colic computed tomography protocol in patients with flank or back pain and absence of pyuria.

OBJECTIVES: The study was undertaken to determine the prevalence and clinical importance of alternative causes of symptoms discovered in patients undergoing flank pain protocol (FPP) computed tomography (CT) scans in patients with classic symptoms of kidney stone (flank pain, back pain, or both) without evidence of urine infection. METHODS: This was a retrospective observational analysis of all adult patients undergoing FPP CT scans at two emergency departments (EDs) between April 2005 and November 2010. All CTs (N = 5,383) were reviewed and categorized as "no cause of symptoms seen on CT," "ureteral stone as cause of symptoms," or "non-kidney stone cause of symptoms." Non-kidney stone scans were further categorized as "acutely important," "follow-up recommended," or "unimportant cause," based on a priori diagnostic classifications. All nonstone causes of pain and a random subset of subjects (n = 1,843; 34%) underwent full record review blinded to CT categorization to determine demographics, whether flank and/or back pain was present, and whether there was objective evidence of pyuria. RESULTS: Of all FPP CT scans during the study period, a ureteral stone was found to cause symptoms in 47.7% of CTs, with no cause of symptoms found in 43.3% of CTs. A non-kidney stone diagnosis was found in 9.0% of all CTs, with 6.1% being categorized as "acutely important," 2.2% as "follow-up recommended," and 0.65% with symptoms from an "unimportant cause." In the randomly selected subset undergoing full record review, categorizations were similar, with 49.0% of CTs showing kidney stone as cause of pain and 9.0% a non-kidney stone cause (5.9% "acutely important"). When subjects with evidence of urine infection or without flank or back pain were excluded, ureteral stone was identified as the cause of pain in 54.9% of CTs, while non-kidney stone cause of symptoms was found in 5.4% of scans and acutely important alternate causes in 2.8% of scans. CONCLUSIONS: While a non-kidney stone cause for a patient's symptoms are found in nearly 10% of CTs done using a FPP, acutely important findings occur in less than 3% of scans done in patients with flank or back pain and absence of pyuria.