Continuous Positive Airways Pressure, or CPAP, is widely regarded as the best treatment available for obstructive sleep apnea. When properly set and consistently used, it is highly effective, though early on tolerance and compliance can be an issue. It may be easy to tell when a CPAP machine is working, but what are signs that it is not working anymore? Consider some of the major indications that your CPAP machine and equipment may need to either be adjusted or replaced. Here are some of the more typical scenarios: