Used that term, and need to explain abit more...
They are just stuff that occurs in clinical practice that adversely affects the patients without their realizing it, and that doctors and hospitals like to pretend don't exist. They are just invisible. Until someone points them out.
What are some of these?
For one thing, diseases caused by doctors. These are called in our jargon, iatrogenic diseases. Often just unsavoury outcome of a reasonable practice. But sometimes can be bad outcome of unsavoury practice. Side effects of drugs, for example.
Bad surgery. How many of these surface? Do hospitals track poor/bad outcome?
Stuff like that. They remain largely invisible, because people wear blinkers and pretend they don't exist. Why? simply because they cost money to prevent, even though they will eventually save health care costs because preventing them decreases overall morbidity. And reduced morbidity will eventually save health care $$. But hospitals and doctors tend not to want to deal with this because their accounting is too simplistic to take into consideration health $$ savings of this nature. As long as the patient/consumer is prepared to pay for the increased morbidity, why bother spending money from your own coffers for good preventive medicine. You can't bill the patient/consumer for preventive measures.
5 years ago