3.4 Agreement between MBW operator and reviewer after implementing real-time quality control
After implementing real-time quality control, the agreement between operator and reviewer was high in both centers. For test acceptability agreement was 97% (ĸ = 0.9, p < 0.001) in Bern and 100% (ĸ = 1.0, p < 0.001) in Zurich. In Bern, only one test occasion was rejected by the reviewer but not by the operator. The remaining four test occasions rejected by the reviewer were also rejected by the operator. In Zurich, all test occasions rejected by the reviewer were also rejected by the operator.
For trial grading, agreement was 68% (ĸ = 0.6, p < 0.001) in Bern and 73% (ĸ = 0.6, p < 0.001) in Zurich. In Bern, the operators were able to recognize all technically invalid trials (F grade). All F grade trials consisting of leaks were identified by the operator. The only trials in which the end of test criteria was not met were trials that were prematurely terminated by the operator. All the trials evaluated satisfied the start of test criteria, which meant that operators were consistently waiting enough time between trials. Three trials were given a C grade by the operator and a D grade by the reviewer due to irregular breathing pattern. However, these trials were then excluded by both as not being accompanied by a second good quality trial. Only one trial with a D grade was rejected by the reviewer but not by the operator. In Zurich, only one F grade trial that did not meet the end of test criteria was not recognized by the operator. Leaks were all correctly identified by the operator. As in Bern all trials satisfied the start of test criteria. One trial was given a D grade by the reviewer and a C grade by the operator, however, both were rejected for final reporting as not being accompanied by a second good quality trial.