Been thinking about this concept today when trying to figure out where you spend your time and resources to harden your system. At least in medicine, in most processes, it’s a team sport. In those instances, it is unlikely that a single bad decision by a single person will go unnoticed and uncorrected. For example, if you post a patient for surgery who is far too sick to survive the operation. In academic medicine, the resident will see the patient and will likely ask you to explain why the patient needs the operation. Then the pre-op center (which almost every hospital has in one form or another) will evaluate the patient and throw a flag. Then even if they get by that, on the day of surgery the patient will be seen by a pre-op nurse and an anesthesiologist,who all can stop the process. Finally there is the operative team and the time out as final checks before you proceed.
Even in emergency surgery, there is an Emergency Medicine physician, anesthesiologist, and surgical team laying eyes and hands on the patient who can stop a bad decision. In the course of an operation, a single person can certainly cut the wrong thing and cause problems, but as far as cutting something and no one noticing, it is possible, but unlikely. If you cause bleeding, everyone will notice, if you do something else, your surgical assistant will notice, the scrub nurse or tech, and possibly the anesthesiologist, not to mention all the post-op care the patient will receive where it can be discovered.
So when you look at our systems, there are really only a few places where a single error by a single person can resonate, and that is at off hours when staffing is low. In those cases a single nurse or respiratory therapist could be caring for more patients than during the day, and could gloss over significant findings. Since there is no one checking after them until the morning, the error can propagate. An on-call physician can also make a serious error, but there is the safety measure of a nurse at the bedside that can protect the patient from the error, and an escalation of care system that can bring more senior people to the bedside to re-evaluate. That is why empowering the nurse to speak up, and empowering everyone to call for more help is vital.
As I’ve said before, the difference between medicine and other high reliability industries is medicine’s proclivity for putting people alone into high risk situations. Fire has the company officer always backing up the firefighter, the military always has the corporal and sergeant, and aviation (in most cases) has a co-pilot and avionics to alarm and intervene. In medicine we need to get back the experienced charge nurse whose only duty is to look out for the safety of their patients, and set tripwires for problems where if the data is consistently abnormal, the information is spread across the providers wide enough to insure that an adequate response occurs.