Following up on MADiE-2127 regarding the issue with having 99% coverage. The last comment in the thread mentioned the following regarding CMS1218 solutions to address the issue:

CMS1218 - Hospital Harm - Postoperative Respiratory Failure – 99% coverage - Issue differs from ticket. The team identified missing coverage within "Encounter with Tracheostomy Before Day of First OR Procedure". Null check on starts before day of missing null scenario. The team also identified missing coverage within "Extubation with Preceding Noninvasive Oxygen". 
Null check on ExtubationTime missing null scenario.  

We created test cases that has null for the timings. We created test case #149, ExtubationTimeMissing, and test case #151, TracheostomyProcedureNoTiming, both of which include a null for timings. However, after running the test cases against the measure, we're still seeing only 99% coverage.