Objectives: To determine whether the Mac-technique test can detect kinking of the chest tube upon thoracostomy tube placement.
Methods: This was a prospective observational study that was conducted October 2000 through October 2001 in an urban Level 1 trauma center. There were 103 consecutive nonrandomized adult trauma patients who required immediate tube thoracostomy during their initial resuscitation who were entered into the study. The Mac-technique test was performed during standard tube thoracostomy insertion to the appropriate depth. The test involved grasping the external portion of the thoracostomy tube, turning it clockwise 180 degrees, and then releasing the tube. If the tube spontaneously spun back to its original position, the test was considered positive, and the tube was considered kinked. If the tube did not spontaneously spin back and stayed in position upon release, the test was considered negative. Regardless of the results of this test, the tube was secured, and a postprocedure chest radiograph was obtained. The criterion standard for determining a kinked chest tube was its appearance on this chest radiograph.
Results: A total of 103 chest tubes were placed by using the Mac-technique test. The test was positive in eight placements; four tubes were kinked on chest radiograph. The Mac-technique test was negative in 95 placements; four tubes were kinked on chest radiograph. The Mac technique had a sensitivity of 50% (95% confidence interval [CI] = 15.7% to 84.3%), a specificity of 95.8% (95% CI = 89.6% to 98.8%), a positive likelihood ratio of 11.9, a negative likelihood ratio of 0.52, and an odds ratio using Yates correction of 20.3 (95% CI = 4.1 to 102.1).
Conclusions: On the basis of this study, a positive Mac-technique test is useful to detect chest tubes that are likely to be kinked after insertion and before securing.