An investigative report by the The Center for Public Integrity (CPI) has found that medical devices that are difficult-or impossible-to clean properly are increasingly behind adverse events.

"FDA has done little to solve the problem, despite review findings that suggest [dirty devices are] widespread," writes CPI. FDA does require manufacturers to prove that its cleaning instructions are effective, but CPI's report questions if their regulatory approach is effective.

The reports showcases a litany of dirty devices, including rusted suction tips, surgical drills dirtied with tissue and bone fragments, and dirty colonoscopy devices that may have spread HIV to patients.

Experts interviewed by CPI cited a number of causes for the dirty devices, including:

• poor manufacturing design
• the complexity of devices
• inadequate training for physicians and surgeon
• the time it takes to sterilize devices
• pressure to get devices ready for other operations

More: The Center for Public Integrity - Filthy surgical instruments: The hidden threat in America's operating rooms