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Three Part Question

Can examination with the [ultrasound transducer] of [patients presenting with an AAA to the Emergency Department] [precipitate deterioration of the AAA clinical course]

Clinical Scenario

A patient presents to the Emergency Department (ED) breathless, distressed and complaining of pain with a pulsating mass in the abdomen. You wish to investigate for an abdominal aortic aneurysm (AAA) using the portable ultrasound unit at the bedside. You recall that peers on a recent ED ultrasound refresher course feared that sufficient compression of the AAA with the transducer in order to get a good image would precipitate a deterioration of the clinical course. You wonder whether there is any evidence surrounding this perception.

Search Strategy

Medline In-process & other non-indexed citations and Ovid Medline 1950 –August week 5 2007 and EBM reviews – Cochrane Central Register of Controlled Trials 3rd Quarter 2007 and the Cochrane Database of Systematic Reviews 3rd Quarter 2007 using the Ovid interface.
[(ultraso$.mp.) OR (sonogr$.mp.) OR (transducer.mp.) OR (probe.mp.)] AND [((accident and emerg$).mp.) OR ((A and E).mp.) OR (A & E.mp.) OR (ED.mp.) OR (emergency departme$.mp.) OR (casualty.mp.)] AND [(abdominal aortic aneury$.mp.) OR (AAA.mp.) OR (aneurysm.mp.)] AND [(deteriora$.mp.) OR (deleterio$.mp.) OR (contraindica$.mp.) OR (contra-indicat$.mp.) OR (rupture.mp.) OR (perforat$.mp.) OR (dissect$.mp.)].

Search Outcome

Altogether 47 papers were found in Medline, 0 papers were found in the Cochrane Central Register of Controlled Trials 3rd Quarter 2007 and 16 papers were found in the Cochrane Database of Systematic Reviews 3rd Quarter 2007; of which 0 were relevant. Additionally a PubMed search [AAA AND examination] and [AAA AND iatrogenic] yielded 0 relevant papers.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses

Comment(s)

Upon removing the set of search terms that make this review specific to the ED, i.e. (accident and emerg$).mp., Medline returns 1596 articles, restricting this search to 'Latest Update' returns no other articles that may suggest an inherent danger in examining the AAA abdomen. Ultrasound is utilised as the primary non-invasive investigation (German translation) in vascular surgery (Lang, 2007). This modality of screening for AAA in asymptomatic individuals has been shown to reduce mortality significantly in the 65 – 79 age group (Cosford & Leng, 2007). These papers, although not directly relevant to the question here, demonstrate that there is little evidence to suggest that ultrasound examination of the AAA will cause any harm. Evidence collected over 12 months from a UK tertiary ED where patients were followed up for a minimum of 5 months showed that 50/119 patients had the ED focussed US as the single imaging modality and had not ruptured at follow-up; consistent with the literature, ED US examination was sensitive and specific (Dent et al., 2007). This data lends further strong support for ED US AAA assessment; however this study did not explicitly look at death as result of examination as an outcome.

Clinical Bottom Line

Currently there is no evidence to suggest that compression of the abdomen with an ultrasound probe, in order to gain a good image for assessment, can cause any deterioration in the natural clinical course of an AAA. The investigation has proved useful in vascular surgery and if anything reduces mortality, therefore adequate compression should be made within the ED, or acute care setting, in order to carry out the investigation correctly for maximal accurate clinical information, as there is no evidence for this causing harm.

References

1. Lang W Ultrasound in vascular surgery Chirurg 2007: 78(5);428, 430-434
2. Cosford PA, Leng GC Screening for Abdominal Aortic Aneurysm Cochrane Peripheral Vascular Diseases Group 2007: 00075320-100000000-01897
3. Dent B, Kendall RJ, Boyle AA, Atkinson PRT Emergency ultrasound of the abdominal aorta by UK emergency physicians: a prospective cohort study Emerg Med J 2007;24(8):547-549