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Three Part Question

In [patients presenting to emergency department with early pregnancy complications] is [ultrasound scan done by emergency physician] useful in [screening for ectopic pregnancy]

Clinical Scenario

on friday night in a busy ED, a 22 year old single female law student presents with lower abdominal discomfort and per vaginal spotting for 12 hours. She is primigravida, with unplanned pregnancy which happened while she was on oral contraceptive pills. She does not have any other significant medical history. She is afebrile. Pulse of 75/min, B.P is 126/79 with postural drop of 15mm(Hg). Abdominal examination is completely normal. Urine dip shows positive B HCG and blood test are completely normal. The timeliest appointment in early pregnancy unit is not available till Monday. You are concerned about sending this patient home. You have an ultrasound machine available in department. Can this ultrasound be used as a screening tool to risk-stratify this patient with any degree of certainty during first consultation in ED? What does the evidence say?

Search Strategy

1) The following data bases were searched via the Ovid interface, from 1965 till current.
CINAHL
Medline
Embase
Cochrane Library
2- Further searches were carried out on
Google
Google scholar
Abstract of all the papers identified were checked for relevance to our clinical question.
References cited in original papers were also checked to identify further relevant papers.
Exclusion criteria:
Limit to: Human and adults (Human Age Groups Adult 18 to 64 years).
Studies were excluded where US studies were not done by emergency physicians.

No. Database Search term Hits
1 MEDLINE (ectopic AND pregnancy).ti,ab 7472

2 MEDLINE *PREGNANCY, ECTOPIC/ 7113

3 MEDLINE 1 OR 2 10874

4 MEDLINE (ultrasound OR ultrasonography OR sonography).ti,ab 181750

5 MEDLINE *ULTRASONOGRAPHY/ 34334

6 MEDLINE 4 OR 5 194724

7 MEDLINE emergency.ti,ab 122477

8 MEDLINE *EMERGENCIES/ 9200

9 MEDLINE 7 OR 8 126618

10 MEDLINE 3 AND 6 AND 9 177

11 MEDLINE 10 [Limit to: (Publication Types Clinical Trial, All)] 1

12 MEDLINE 10 [Limit to: Humans] 168

13 MEDLINE 12 [Limit to: Humans and (Age Groups All Adult 19 plus years)] 110

14 EMBASE (ectopic AND pregnancy).ti,ab 8319

15 EMBASE *ECTOPIC PREGNANCY/ 9394

16 EMBASE 14 OR 15 12722

17 EMBASE (ultrasound OR ultrasonography OR sonography).ti,ab 222091

18 EMBASE *ULTRASOUND/ 20923

19 EMBASE 17 OR 18 229740

20 EMBASE emergency.ti,ab 144702

21 EMBASE *EMERGENCY/ OR *EMERGENCY HEALTH SERVICE/ OR *EMERGENCY MEDICINE/ OR *EMERGENCY PHYSICIAN/ OR *EMERGENCY WARD/ OR *EVIDENCE BASED EMERGENCY MEDICINE/ 55342

22 EMBASE 20 OR 21 168788

23 EMBASE 16 AND 19 AND 22 224

24 EMBASE 23 [Limit to: Human and (Human Age Groups Adult 18 to 64 years)] 135

Search Outcome

After reading through abstracts of 135 papers identified by the search,10 papers were identified as being directlty relevant to the clinical question

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Davis DP, Campbell CJ, Poste CJ et al. 2005 USA	adults.Evaluating effectiveness of US examinations done by emergency physicians for presence or absence of 6 different conditions. These conditions are 1- peritoneal fluid 2- pericardial fluid 3- gallstones 4- intrauterine fetus 5-hydronephrosis 6- abdominal aorta’s diameter. Data was collected for all eligible exams after one year and ED US results were compared to gold standard investigations. Overall 276 scans were included with sensitivity of 92% and specificity of 86%	This is a single centre prospective study. Evaluating effectiveness of US examinations done by emergency physicians for presence or absence of 6 different conditions. These conditions are 1- peritoneal fluid 2- pericardial fluid 3- gallstones 4- intrauterine fetus 5-hydronephrosis 6- abdominal aorta’s diameter. Data was collected for all eligible exams after one year and ED US results were compared to gold standard investigations. Overall 276 scans were included with sensitivity of 92% and specificity of 86% Primary outcome measure for early pregnancy scans was determination of intra uterine pregnancy. Out of 70 early pregnancy scans done by emergency physicians 52 (74%) positively identified intrauterine pregnancy. When comparing with gold standard, this gives 100% sensitivity and specificity with positive and negative predictive value of 100%.	negative predictive value	100%	, data was collected for effectiveness for 6 different conditions, intra uterine pregnancy being one of them. Thus the study is more relevant for overall effectiveness of scans. Study has been done with no power calculation to determine sample size. Data has been collected retrospectively by the operators themselves, so there is no blinding. The data is presented in percentages not in absolute numbers, confounding the results somewhat
			specificity	100%
Adhikari S, Blaivas M and Lyon M 2007 USA	Pregnant patients with first trimester complications	This is a retrospective single centre study. Only data of positive ED scans (ectopic/ possible ectopic) is being presented, which allows for calculation of positive predictive value only. There is no mention of the final outcome of the patients whose scans were deemed negative in ED. Out of positive scans, patients with small amount of peritoneal fluid with empty uterus but no other findings suggestive of ectopic pregnancy has been excluded. This can lead to purity bias. Results are analysed as per protocol analysis. There is no power calculation, no mention of blinding when reporting results. Study design is poor for a diagnostic study and sensitivity and specificity of the test cannot be calculated as negative results have not been included in the study. Out of 74 scans deemed positive or suspicious for ectopic pregnancy, 47 patients received final diagnosis of ectopic pregnancy. This gives positive predictive value of 63.5%.	positive predictive value	63.5%	Out of positive scans, patients with small amount of peritoneal fluid with empty uterus but no other findings suggestive of ectopic pregnancy has been excluded. This can lead to purity bias. Results are analysed as per protocol analysis. There is no power calculation, no mention of blinding when reporting results. Study design is poor for a diagnostic study and sensitivity and specificity of the test cannot be calculated as negative results have not been included in the study.
Christina HY Shih 1996 USA	pregnant patients with first trimester complications	Notes were reviewed of 127 patient who underwent pelvic US in emergency department mostly by emergency physicians but also by obs and gynae residents. Primary outcome measure is the length of stay analysis amongst the group that had US done by ED physician compared with the group that had scan performed by gynae resident. LOS for group one is 60 minutes compared to LOS of group B of 180 minutes. In secondary outcome measure 74 scans were done by ED physicians. 47 IUP’s were correctly identified with no false +ve’s. Out of 24 true –ve IUP’s 6 were ectopics which were all positively identified by ED physicians. Plotting this data gives us: Sensitivity =100% Specificity = 72% Positive predictive value = 22% Negative predictive value =100%	negative predictive value	100%	On –ve side it’s a single centre, retrospective study. Study utilizes a convenience sample with no power calculation. It does not give absolute numbers for true and false –ve’s in IUP analysis.
Wong TW, Lau CC, Yeung A et al. 1998 Hongkong, China	all pregnat women within first trimester, presenting with pain and/or bleeding during five months period from February to June 1996.	It’s a prospective single centre trial. Enrolling all women presenting with pain and/or bleeding during five months period from February to June 1996. Haemodynamically unstable patients and patients with previous US scans were excluded. Scans were done by emergency physicians using trans-abdominal probe only. Sensitivity =80% Specificity = 80% Positive predictive value = 12% Negative predictive value = 99%	negative predictive value	99%	Authors used a convenience sample with no power calculation. Had a reasonable inclusion and exclusion criteria. There is no mention of blinding while collating the results. Absolute numbers are not given in the results.
Mateer JR, Valley TV, Aiman EJ et al 1996 USA	pregnant patients with first trimester complications	Single centre prospective case control trial with historical control. Sample is a convenience sample over period of three years. All eligible were enrolled with no significant exclusions. 314 patients finally enrolled in control group out of which 14 were excluded due to incomplete data. Thus giving us per protocol analysis. Primary outcome measure was number of patients discharged from ED subsequently found to have ruptured ectopic pregnancy. 1/11 in intervention group and 12/24 in control group, who were discharged from ED with ectopic pregnancy, were subsequently found to have ruptured ectopic pregnancy. CER= 50 EER=9.09 ARR= 40.91 RRR=81% NNT=2.4 This is a very significant result considering seriousness of the primary outcome.	RRR	81%	On –ve side study uses a historical control, thus improvement of service, if any, over time may account for some of the relative risk reduction that is observed amongst both groups. It’s a single centre study with relatively small sample size so possibility of type 1 error cannot be ignored.
			NNT	2.4

Comment(s)

all papers reviewed are in agreement that ED performed US has a negative predictive value approaching 100% when surveying patients with early pregnancy complications for ectopic pregnancy.

Editor Comment

.

Clinical Bottom Line

US in ED by ED physicians is definitely way forward in screening for ectopic pregnancy.

Level of Evidence

Level 2 - Studies considered were neither 1 or 3.

References

1. Davis DP, Campbell CJ, Poste CJ et al. The association between operator confidence and accuracy of ultrasonography performed by novice emergency physicians the journal of emergency medicine 2005. vol 29, no 3; 259-264
2. Adhikari S, Blaivas M and Lyon M Diagnosis and management of ectopic pregnancy using bedside transvaginal ultrasonography in the ED. A 2 year experience American journal of emergency medicine 2007. 25; 591-596
3. Durham B, Lane B, Burbridge L and Balasubramaniam S Pelvic ultrasound performed by the emergency physicians for detection of ectopic pregnancy in complicated first trimester pregnancies annals of emergency medicine march 1997, 29:3;338-347
4. Christina HY Shih Effect of emergency physician-performed pelvic sonography on length of stay in emergency department annals of emergency medicine march 1997, 29:3;348-351
5. Wong TW, Lau CC, Yeung A et al. efficacy of transabdominal ultrasound examination in the diagnosis of early pregnancy complications in an emergency department journal of accident and emergency medicine 1998. 15; 155-158
6. Mateer JR, Valley TV, Aiman EJ et al Outcome analysis of a portocol including bedside endovaginal sonography in patients at risk of ectopic pregnancy annals of emergency medicine march 1996. 27:3;283- 289
7. Jehle D, Evan T, Harchelroad F et al Emergency department sonography by emergency physicians american journal of emergency medicine nov 1989,vol 7; 605-611
8. Burgher SW, Tandy TK, Dawdy MR Transvaginal ultrasonography by emergency physicians decreases patient time in the emergency department Academic emergency medicine august 1998, vol 5(8);802-807
9. Mateer JR, Aiman JE, et al Ultrasonographic examination by emergency physicians of patients at risk for Ectopic pregnancy Academic emergency medicine 1995, vol 2(10); 867-873
10. Durston WE, Carl M, Guerra W et al. Ultrasound availibility in the evaluation of ectopic pregnancy in the ED: Comparison of quality and cost-effectiveness with different approaches american journal of emergency medicine 2000. vol 18(4); 408-416