Table 1

Author, date and countryPatient groupStudy type (level of evidence)OutcomesKey resultsStudy weaknesses
Stapakis JC et al, 1992, USA13 patients with known pneumoperitoneum after diagnostic peritoneal lavageDiagnostic study of upright PA chest radiograph against CT of abdomenSensitivity of chest radiograph and CT for detection of pneumoperitonemCT demonstrated free gas in all casesIatrogenic pneumoperitoneum
Small numbers of cases
What size collection is clinically relevant?
Woodring JH et al, 1995, USA100 consecutive patients with pneumoperitoeum from a variety of causesDiagnostic studySensitivity of upright PA chest radiograph80%Pneumoperitoneum form a variety of causes
Sensitivity of lateral upright chest radiograph98%Only 7 patients presenting as emergencies with acute perforated abdominal viscus
Difference between upright and lateral18% p<0.01Gold standard for pneumoperitoneum variable
Sensitivity of both radiographs100%