Trigger point injections for abdominal wall pain: Discussion (Part 2)
Each study had a slightly different patient base, different inclusion and exclusion criteria and use of the Carnett test, and different combinations of injected agents. One of the purposes of the present study was to try to determine which of these factors are important in predicting response. When faced with a patient with suspected AWP, knowing these factors would then help the physician select patients who would benefit the most from TPI.
Meeting physical examination criteria for AWP was one such factor. In Carnett’s original article, he suggested that “almost or quite as much” tenderness with abdominal wall tensing compared with the relaxed state was indicative of AWP. Subsequently, the use of the Carnett test has been examined. Thomson and Francis found that only one of the 24 patients (4%) with a positive Carnett’s test admitted as an emergency was later found to have a visceral cause. Gray et al later reported that five of 53 patients (9%) with a positive Carnett’s test had appendicitis. Other studies have shown similar false-positive rates. An argument could be made that these false-positive rates are too high for missing potentially lethal diseases. ventolin inhaler