The word preventable can be misleading. It may imply that preventive perfection (zero harm) is possible. It does imply that some things are not preventable; sometimes these harms are distinguished by the label “complications”.
I like to take the view that all harm is at least to some extent preventable, and that there exist ways to minimize the risk of any given harm associated with any given procedure. It is a continuum. Sometimes, as in with central line infections, we have highly effective methods to minimize the risk, and then we label and declare all central line infections preventable. Other times we honestly don’t have methods to reliably minimize risk for a particular harm, and we do not consider it preventable. In these cases we declare the harm to be an unpreventable complication, i.e. “these things happen”. An example of this would be central line infections…15 years ago. I would argue that unpreventable complications are really just cases where we don’t yet have the knowledge, skills, science, or technology to reliably reduce the risk of a given harm.
So when we call an incident preventable harm, what we really mean is the following: “we had proven, highly effective methods to minimize the risk of this harm to near-zero, and for whatever reason the harm still occurred. In this setting, the most likely cause of harm is some deviance from the highly effective methods for as of yet unknown reasons. Far less likely–but not impossible–is that everything had been done right and somehow the harm still occurred, and as of right now we don’t know how.”
When we call something unpreventable, what that translates to is that we don’t yet know of any proven methods to reduce the risk of this harm in this setting. It does not mean that we will never someday discover such methods. It especially does not mean we should not try to discover such methods; in fact it may be just the opposite.
I would like to, but I don’t believe zero harm is possible. Nothing is perfect. Just as people are fallible, systems are fallible, and even really good evidence-based safety protocols are fallible. Given enough knowledge of how a person, system, or protocol is set up, you can always contrive a set of conditions, however unlikely or nigh-implausible, that will evoke failure.
That said, we can get pretty close to zero. 1 in 300,000 is the risk of serious harm due to anesthesia in healthy patients; that is pretty impressively close to zero.
Our goal has to be zero, perfection; nothing else is justifiable, and yes, it is that simple. Is it pointless to set an impossible, unrealistic goal? No, because there is a point, at least to this one. The fact that our goal is impossible is another way of saying that we should never stop working to be better.