Does conformity with standard practice insulate a doctor from negligence?

In ter Neuzen v. Korn (1995), 127 D.L.R. (4th) (S.C.C.), Sopinka J. wrote, at para. 43 Thus, it is apparent that conformity with standard practice in a profession does not necessarily insulate a doctor from negligence where the standard practice itself is negligent. The question that remains is under what circumstances will a professional standard practice be judged negligent? It seems that it is only where the practice does not conform with basic care which is easily understood by the ordinary person who has no particular expertise in the practices of the profession. That is, as Professor Fleming suggests, where the common practice is fraught with danger, a judge or jury may find that the practice is itself negligent. …. I conclude from the foregoing that, as a general rule, where a procedure involves difficult or uncertain questions of medical treatment or complex, scientific or highly technical matters that are beyond the ordinary experience and understanding of a judge or jury, it will not be open to find a standard medical practice negligent. On the other hand, as an exception to the general rule, if the standard practice fails to adopt obvious and reasonable precautions which are readily apparent to the ordinary finder of fact, then it is no excuse for a practitioner to claim that he or she was merely conforming to such a negligent common practice.