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Three Part Question

In [adults with suspected cholelithiasis] does [gall bladder ultrasonography performed by emergency physicians] have [adequate diagnostic accuracy]?

Clinical Scenario

A 40-year-old female presents to the emergency department with epigastric abdominal pain and nausea. Her WBC count and transaminases are within normal limits and her symptoms improve with pain medication and antiemetics. You wonder if performing bedside ultrasound (US) will be sufficient to rule-out cholelithiasis and hasten her disposition.

Search Strategy

Ovid MEDLINE(R) 1950 to June Week 2 2009, EMBASE 1980 to 2009 Week 25 using multifile searching
([exp ultrasonography/ OR ultrasonography.mp. OR ultrasound.mp.]) AND [cholelithiasis/ OR cholelithiasis.mp. OR exp gallstones/ OR gallstones.mp OR cholecystolithiasis.mp. OR choledocholithiasis.mp.] AND [exp emergency medicine/ OR A&E.mp OR Emergency Service, Hospital/ OR emergency department.mp OR Emergency Medical Services/ OR accident & emergency.mp OR casualty.mp OR emergency room.mp] AND [exp Diagnosis/ OR diagnosis.mp OR sensitivity.mp OR "Sensitivity and Specificity"/ OR specificity.mp]) Limit to human and English
The Cochrane Library Issue 2 2009: (cholecystolithiasis ti, ab, kw) - 49 records 0 relevant (gallstones):ti,ab,kw AND MeSH descriptor Ultrasonography explode all trees - 23 records 0 relevant

Search Outcome

106 unique papers were found of which five were relevant to the three part question. The five relevant papers are summarised in the table

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Miller AH et al, 2006, USA	Convenience sample of patients >18 years of age having both emergency physician (EP) performed US and radiology department US of the gallbladder for evaluation of abdominal pain. 132 patients were enrolled and 105 had evidence of cholelithiasis by radiology department US.	Prospective observational study	Sensitivity	0.90 (0.84-0.95)	Convenience sample, lack of follow-up, 43% of examinations performed by one faculty member with considerable ultrasound experience
			Specificity	0.96 (0.93-0.99)
			PPV	0.99 (0.97-1.00)
			NPV	0.73 (0.65-0.82)
			LR	6.78 (3.01-15.28)
Davis DP et al, 2005, USA	Convenience sample of patients receiving US examination by EPs during the first year after initiation of a departmental training program. 105 patients receiving gallbladder US were enrolled. 62 of these patients were found to have cholelithiasis.	Prospective observational study	Sensitivity	0.81 (0.69-0.90)	Convenience sample
			Specificity	0.86 (0.72-0.95)
			Accuracy	0.83 (0.74-0.90)
			LR+	5.8 (2.9-12.4)
			LR-	0.22 (0.13-0.37)
			Operator confidence	Higher levels of operator confidence correlated with improved test performance
Durston W, et al, 2001, USA	754 unique EP US examinations were performed (24.5% positive for gallstones) Accuracy of EP US assessed by comparing results with surgical pathology, radiology department imaging, or clinical follow-up at 2 years.	Observational study	Sensitivity	0.886 (0.831-0.928)	EP US accuracy was a secondary outcome
			Specificity	0.982 (0.960-0.993)
			Accuracy	0.948 (0.925-0.965)
Kendall JL and Shimp RJ, 2001, USA	Convenience sample of 112 ED patients receiving formal radiology department ultrasound (US) for epigastric/RUQ abdominal pain or jaundice. 51 had gallstones diagnosed on formal study.	Prospective observational study	Sensitivity	0.96 (0.87-0.99)	Convenience sample, relatively small sample size for subgroup analysis by experience level
			Specificity	0.88 (0.77-0.95)
			PPV	0.88
			NPV	0.96
			Sensitivity (>25 scans)	1.0
Rosen CL et al, 2001, USA	116 patients with suspected biliary colic underwent bedside abdominal ultrasound by the attending emergency physician. 69 had gall stones. All underwent formal ultrasound blinded to the bedside result	Prospective diagnostic cohort	Sensitivity	0.92 (0.73 – 1)
			Specificity	0.78 (0.61 – 0.93)
			PPV	0.86 (0.57 – 1)
			NPV	0.88 (0.67 – 1)
			Accuracy	0.86 (0.72 – 1)

Comment(s)

Evidence to date shows that ultrasound (US) performed by emergency physicians has reasonable sensitivity (0.81-0.96) and specificity (0.86-0.98) for detection of cholelithiasis. All studies included here were performed after initiation of emergency department specific ultrasound training programs, with study comparisons made to "gold standard" of radiology department ultrasound, invasive procedure, or follow-up. Improved accuracy was noted with higher levels of experience (>25 scans) and exam confidence. Durston et al. noted improved quality of care and decreased cost associated with evaluation of patients with possible biliary colic as ultrasonography has become more available in the emergency setting. For comparison, a meta-analysis of radiology department US for diagnosis of gallstones by Shea et al. adjusted for verification bias and calculated a sensitivity of 0.84 (0.76 to 0.92) and sensitivity of 0.99 (0.97 to 1.00). Secondary sonographic signs of acute cholecystitis (sonographic Murphy's sign, gallbladder wall thickening, common bile duct dilatation, pericholecystic fluid, etc.) provide additional diagnostic information to the clinician. With the exception of the sonographic Murphy's sign, these are generally less likely to be detected by emergency physician ultrasound. A conservative approach in the ED would be to utilize radiology department ultrasound whenever available, and perform bedside ultrasound only if experience and confidence are such that results will hasten management and/or disposition.

Clinical Bottom Line

Emergency physician performed ultrasound for detection of cholelithiasis has accuracy similar to radiology department ultrasound, but varies with operator experience and confidence. Individual abilities and institutional ultrasound availability must be considered.

References

1. Miller AH, Pepe PE, Brockman CR, Delaney KA. ED ultrasound in hepatobiliary disease. Journal of Emergency Medicine Jan 2006; 30(1):69-74.
2. Davis DP, Campbell CJ, Poste JC, Ma G. The association between operator confidence and accuracy of ultrasonography performed by novice emergency physicians. Journal of Emergency Medicine Oct 2005; 29(3):259-264.
3. Durston W, Carl ML, Guerra W, Eaton A, Ackerson L, Rieland T, Schauer B, Chisum E, Harrison M, Navarro ML. Comparison of quality and cost-effectiveness in the evaluation of symptomatic cholelithiasis with different approaches to ultrasound availability in the ED. American Journal of Emergency Medicine Jul 2001; 19(4):260-269.
4. Kendall JL, Shimp RJ. Performance and interpretation of focused right upper quadrant ultrasound by emergency physicians. Journal of Emergency Medicine Jul 2001; 21(1):7-13.
5. Rosen CL, Brown DF, Chang Y, Moore C., Averill NJ, Arkoff LJ, McCabe CJ et al. Ultrasonography by emergency physicians in patients with suspected cholecystitis. Am J Emerg Med 2001;19: 32-6.
6. Shea JA, Berlin JA, Escarce JJ, Clarke JR, Kinosian BP, Cabana MD, Tsai WW et al. Revised Estimates of Diagnostic Test Sensitivity and Specificity in Suspected Biliary Tract Disease. Arch Intern Med 1994;154:2573-81.