After settling in Montreal in 1957, Maurice McGregor helped establish and co-directed the joint Cardio-Respiratory Service affiliated with two of McGill's teaching hospitals, the Royal Victoria Hospital and
Montreal Children's Hospital. Within this service, McGregor studied less invasive ways of measuring
cardiac output in children, in collaboration with Paul Sekelj, inventor of one of the first whole-blood oximeters that could be used clinically. McGregor went on to become head of cardiology and then physician-in-chief at the
Royal Victoria Hospital, Montreal, and dean of medicine and vice principal of McGill University. His university leadership roles occurred during a period of widespread protests in the late 1960s and early 1970s, including a doctors’ strike in the fall of 1970 over the advent of national health insurance, a policy that McGregor supported then and since. McGregor proved to be a bridge-builder during this turmoil, arguing in print the following year that "the problem should have been the subject of calm and dispassionate discussion.” In 1973, McGregor and Becklake went to China as part of the
Norman Bethune Exchange Lectureship between McGill University and Peking Medical College. They wrote about witnessing surgery done under acupuncture anesthesia and about research presented to them on that subject, noting the "paucity of up-to-date first-hand reports in the English language" and the importance "that this work be recognized in the West." In 1984, the University of Witwatersrand (Wits) approached McGregor with a request to return to South Africa – then in the throes of turbulence surrounding the dismantling of apartheid – to be dean of medicine. During his leadership time (1984–87), Wits and the nearby black townships of Alexandra and Soweto were rocked by student protests. When a university-affiliated community health clinic in Alexandra treated youths wounded by police shotguns, McGregor went to the clinic and supported the position of his staff to hide the identities of those treated from police. In short, McGregor allied himself with those advocating for change – black medical students were enrolled in record numbers and the five university-affiliated hospitals were desegregated after he personally pressured the hospital directors. From 1989 through 2014, McGregor wrote 26 articles published in peer-reviewed journals, plus 74 other published pieces in books and reports, pushing for systematic reviews of the cost-versus-benefits of each new item of expensive technology and each pricey new drug before it is fully embraced by healthcare providers. He argued that unquestioned acceptance of new technology could cause limited healthcare dollars to be syphoned from more necessary and widely helpful interventions. One of his earliest articles on this subject was published in the
New England Journal of Medicine in 1989, titled “Technology and the allocation of resources.” From 1991 through 1995, McGregor traveled to healthcare conferences across Canada, as well as to Washington D.C., Mexico, Brazil, and England, in response to invitations to explain Quebec's pioneering approach to "rationalizing and improving the use of technology" through systematic assessment. In 2014, the Canadian Agency for Drugs and Technologies in Health created the Dr. Maurice McGregor Award to honor the next generation of experts in health technology assessment. As of 2020, McGregor was the author or co-author of 157 pieces published in peer-reviewed journals on cardiovascular disease, cardiovascular physiology and pharmacology, medical education and health policy, plus 100 book chapters, reports, or other professional publications, and 101 abstracts. As an invited speaker, he gave 94 presentations at conferences held around the world. ==Death==