1. R1. 이성곤 /pf. 정경환 n engl j med 371;12 nejm.org september 18, 2014

2. Abstract **Pain from nephrolithiasis : common reason for ER visits  Abdominal CT: m/c high sensitivity for Dx.  However, 1) Exposure to ionizing radiation (long-term ca. risk↑) 2) Annual care costs↑ : about $2 billion in the US. ; CT use(despite its higher sensitivity) : a/w improved pt. outcomes.? Multicenter, randomized trial comparing US with CT.

3. Method(1) 1) Study design and randomization 15 geographically diverse academic ER, 4 of which were safety-net hospitals Patients(suspected nephrolithiasis): 1:1:1 ratio ① US performed by an emergency physician (point-of-care US) ② US performed by a radiologist ③ Abdominal CT. 2) Study population *2011.10~2013.2: 18~76 yrs of age (flank or abdominal pain)  ER physician imaging order or 1° Dx. Of kidney stone *High risk or obese pts. excluded (acute cholecystitis, appendicitis, aortic aneurysm, bowel d/o, pregnant women or ♂>129kg, ♀>113kg) * Single kidney, RT, dialysis: ineligible SiteLocation Beth Israel Deaconess Medical CenterBoston, MA Grady Memorial Hospital*Atlanta, GA Hennepin County Medical Center*Minneapolis, MN Hospital of the University of PennsylvaniaPhiladelphia, PA Jacobi Medical Center*Bronx, NY John H. Stroger Jr. Hospital of Cook County*Chicago, IL Massachusetts General HospitalBoston, MA Memorial Hermann-Texas Medical CenterHouston, TX Oregon Health & Science University HospitalPortland, OR Rhode Island HospitalProvidence, RI University of California Davis Medical CenterDavis, CA University of California San Francisco-Fresno Community Regional HospitalFresno, CA University of California San Francisco Medical CenterSan Francisco, CA University of Utah Health Care-Hospital and ClinicsSalt Lake City, UT Washington University-Barnes-Jewish HospitalSt. Louis, MO

4. Method(2) 1) Outcomes *Primary outcomes: ① High-risk Dx. (with complications-missed or delayed Dx.: eg. AAA with rupture, pn. c sepsis, appendicitis c rupture, diverticulitis c abscess or sepsis, bowel ischemia, or perforation, renal infarction, renal stone c abscess, pyelonephritis c uro-sepsis or bacteremia, ovarian torsion c necrosis, or aortic dissection c ischemia) ② Cumulative radiation exposure : Sum of the effective doses from all imagin  6mo. After randomization ③ Total costs: National Medicare reimbursements for cost a/w ER visits

5. Method(3) *Secondary outcomes : Pts. Were contacted 3, 7, 30, 90, and 180 days  Utilization of health care service, radiation exposure, and Dx. confirmed by means of a review of the medical records (performed by research coordinators) ① Serious adverse events: untoward medical occurrences : death, were life-threatening, required hospitalization, caused persistent or clinically significant disability, or required medical, surgical, or other intervention to prevent permanent impairment ② Related serious adverse events : Acute cholecystitis, appendicitis, and bowel obstruction ③ Emergency department length of stay ④ Return ER visits and hospitalization after D/C ⑤ Hospital admission after emergency department discharge ⑥ Self-reported pain(visual-analogue scale), ⑦ Diagnostic accuracy

6. Method(4) *Statistical analysis : intention-to-treat principle(except alternative method) : Baseline characteristics & outcomes  Chi-square tests : High-risk Dx. with Cx. & related serious adverse events)  Fisher’s exact test, : Pain score, radiation exposure, & ER length of stay).  Kruskal–Wallis test Distributions for radiatioin exposure: right-skewed~ Sensitivity and specificity : Standards definitions Stratification according to status with respect to a history of nephrolithiasis.

7. Results(1)

8. Result(2)

9. Result(3) 41.6% 63.6% 52.5%

10. Result(4) Only a single imaging exam.?, :Median length of stay in the ER was significantly shorter in the point-of-care US group than in the other 2 groups : 5.1 hrs (IQR, 3.7 ~ 7.4) /6.4 hrs (IQR 4.9 ~ 8.5) /6.2 hrs (IQR, 4.6 ~ 8.7) (P<0.001). Only a single imaging exam.?, :Median length of stay in the ER was significantly shorter in the point-of-care US group than in the other 2 groups : 5.1 hrs (IQR, 3.7 ~ 7.4) /6.4 hrs (IQR 4.9 ~ 8.5) /6.2 hrs (IQR, 4.6 ~ 8.7) (P<0.001). ED discharge diagnosis Final diagnosisDiagnostic delay (days) Point-of-care US Nephrolithiasis Diverticulitis Nephrolithiasis, UTI Nephrolithiasis Non-specific pain Small bowel obx. Bowel ischemia & resection Pyelonephritis, urosepsis, bacteremia Diverticulitis with abscess Pyelonephritis, urosepsis, bacteremia Urosepsis, bacteremia Pyelonephritis, urosepsis, bacteremia 3 4 9 19 21 30 Radiology US Ruptured ovarian cyst Pyelonephritis Nephrolithiasis Ovarian torsion Renal abscess Pyelonephritis, urosepsis, bacteremia 2 3 19 Computed tomography Nephrolithiasis, UTI Nephrolithiasis Pyelonephritis, urosepsis, bacteremia Urosepsis, bacteremia 4 17

11. Result(5)

12. Diagnostic Accuracy for Nephrolithiasis 1) Proportion of pts with a confirmed stone Dx. within 6 mo. : Similar in the 3 study groups (34.5%/31.2%/32.7%; P = 0.39). 2) Pts. in the US groups : more likely additional diagnostic testing  40.7%/27.0%/5.1% (P<0.001). :*Despite the additional imaging tests  mean total costs : slightly lower US group (a difference of $25 btw. CT & Radiology US, P<0.001 3) *1 st imaging test pts. underwent showed that US : lower sensitivity & higher specificity than CT ① Sensitivity : 54% (95% [CI], 48 ~ 60) / 57% (95% CI, 51 ~ 64) / 88% (95% CI, 84 to 92) (P<0.001) ② Specificity :71% (95% CI, 67 ~ 75)/73% (95% CI, 69 ~ 77)/58% (95% CI, 55 ~ 62), (P<0.001). There was no significant difference in results btw those with and those without complete follow-up.

13. Results Stratified According to History of Nephrolithiasis 1) Primary outcomes : ① High-risk diagnoses c Cx.: no significant differences ② Radiation exposure: significantly lower in the US groups 2) Secondary outcomes: Pts in the US groups- less likely additional Dx. testing with CT ;when they reported a Hx. of nephrolithiasis (31% vs. 36%, P<0.001).

14. Conclusion **Initial US : was a/w lower cumulative radiation exposure than initial CT, : w/o significant differences in high-risk diagnoses with complications, serious adverse events, pain scores, return emergency department visits, or hospitalizations. **Initial US : was a/w lower cumulative radiation exposure than initial CT, : w/o significant differences in high-risk diagnoses with complications, serious adverse events, pain scores, return emergency department visits, or hospitalizations.