C.6Review protocol – PE diagnosis (V/Q scan)

Review questionIn people with suspected PE, what is the effectiveness of ventilation perfusion scans in ruling out PE?
ObjectivesTo estimate the diagnostic accuracy of ventilation perfusion scanning.
Criteria for considering studies for the review
Study designRandomised controlled trials and cross sectional studies that are prospective. Reference standard to be tested at same time as the intervention. Studies before 1990 should be excluded as older studies will report older techniques that are now no longer used.
PopulationPatients with suspected pulmonary embolism
InterventionVentilation perfusion scans, both ventilation and perfusion must be tested
ComparisonCT pulmonary angiography, selective/conventional/catheter/invasive/direct pulmonary angiography.
Autopsy should only be used in absence of reference standards listed
OutcomesSensitivity, specificity, PPV, NPV, radiation burden, non-diagnostic rate, 3 month VTE rate.
EqualitiesCancer patients? Mobility issues?
How the information will be searched
Search strategy
The databases to be searched are Medline, Embase, The Cochrane Library and CINAHL.
Studies will be restricted to English language only
No date restriction will be applied. Databases will be searched from their date of origin.
The review strategyInclude studies that perform both ventilation and perfusion.

Haemodynamically unstable or high BMI may be excluded.

Autopsy if there are no studies with pulmonary angiogram as reference standard.

Meta-analysis will not be conducted for diagnostic studies. Ranges of results will be reported.

If there is heterogeneity the following sub-group analysis should be performed: dates of study and types of scans.

From: Appendix C, Review protocols

Cover of Venous Thromboembolic Diseases
Venous Thromboembolic Diseases: The Management of Venous Thromboembolic Diseases and the Role of Thrombophilia Testing [Internet].
NICE Clinical Guidelines, No. 144.
National Clinical Guideline Centre (UK).
Copyright © 2012, National Clinical Guideline Centre.

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