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Three Part Question

In [patients with a possible perforated abdominal viscus] does [a normal erect chest X-ray] exclude [pneumoperitoneum]?

Clinical Scenario

A 37 year old female patient attends the emergency department with a 4 hour history of epigastric pain. The patient has been taking NSAIDs for backache for the last few months. On examination they have mild tenderness in the epigastric region but no peritonism. You wonder whether an erect chest Xray is sensitive enough to exclude a perforation of an abdominal viscus in this patient.

Search Strategy

Medline 1966-11/03 using the OVID interface via ATHENS. Including MEDLINE in progress and non-indexed citations.
({exp Pneumoperitoneum OR exp Intestinal perforation OR exp Abdominal pain OR exp Abdomen acute} AND {exp Radiography, thoracic}) LIMIT to human AND English

Search Outcome

39 papers found of which 2 papers were relevant to the original question.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Stapakis JC et al, 1992, USA	13 patients with known pneumoperitoneum after DPL	Diagnostic study of upright PA chest Xray against CT scan of abdomen	Sensitivity of Chest Xray and CT scan for detection of pneumoperitoneum	CT scan demonstrated free gas in all cases	Iatrogenic pneumoperitoneum Small numbers of cases What size collection is clinically relevant?
Woodring JH et al, 1995, USA	100 consecutive patients with pneumoperitoeum from a variety of causes	Diagnostic study	Sensitivity of lateral upright CXR	98%	Pneumoperitoneum form a variety of causes Only 7 patients presenting as emergencies with acute perforated abdominal viscus Gold standard for pneumoperitoneum variable
			Difference between upright and lateral	18% p<0.01
			Sensitivity of upright PA chest X-ray	80%
			Sensitivity of both XRays	100%

Comment(s)

The available evidence on the sensitivity of upright abdominal chest x-rays at detecting pneumoperitoneum is poor. No studies looked at patients attending the emergency department with abdominal pain. However, the available evidence suggests that an erect postero-anterior chest x-ray is not sufficiently sensitive to be used as a sNout for pneumoperitoneum in such patients. Sensitivity might be improved by performing either an erect lateral chest x-ray or a CT scan.

Editor Comment

Search redone in November 2003. No new papers found.

Clinical Bottom Line

An erect postero-anterior chest x-ray is not sufficiently sensitive to rule out pneumoperitoneum in patients attending emergency departments with abdominal pain.

Level of Evidence

Level 3 - Small numbers of small studies or great heterogeneity or very different population.

References

1. Stapakis JC, Thickman D. Diagnosis of pneumoperitoneum: abdominal CT vs. upright chest film. J Comput Assist Tomogr 1992;16(5):713-6.
2. Woodring JH, Heiser MJ. Detection of pneumoperitoneum on chest radiographs: comparison of upright lateral and posteroanterior projections. American Journal of Roentgenology 1995;165(1):45-7.