The renowned anesthesiologist Dr. James (Jim) Bain died on 29 April 2024, at the age of 89 (Figure). Best known for inventing the eponymous Bain breathing circuit, he was also a dedicated family man and avid sportsman. He is remembered fondly by his many friends and surviving kin, as well as innumerable colleagues and mentees across the globe.

Dr. James Bain during medical school (left panel) and as a Professor Emeritus (right panel). Photographs courtesy of Dr. Halina Kieraszewicz and the late Dr. James Bain.

Dr. Bain was born on 6 July 1934, in Listowel, ON, Canada, the fourth of five children. His family later moved to London, ON, Canada, where he completed secondary school. He received his medical degree from the University of Western Ontario in 1959 and completed an internship at St. Michael’s Hospital in Toronto. Initially, he worked in general practice and in internal medicine until returning to London for an anesthesiology residency at the University of Western Ontario. The department there was helmed by the influential Dr. Wolfgang Spoerel, who hired Dr. Bain once he completed his residency. Dr. Bain maintained an interest in neuroanesthesia and cardiac anesthesia throughout his 45-year career, until his retirement in 2003.

Perhaps Dr. Bain’s most enduring professional legacy is his invention, the Bain breathing circuit (sometimes referred to by its creator as the “BBC”). His invention arose in 1971 from his dissatisfaction with then-available breathing circuits. The Mapleson A (Magill attachment) suffered from an awkward, bulky pop-off valve near the patient’s face and was poorly suited to controlled ventilation. Alternatively, the Jackson Rees circuit (Mapleson D modification; also called Mapleson F) was popular for controlled ventilation in pediatrics but required very high fresh gas flows and posed challenges in regulating patients’ PaCO2.

The Bain circuit was Dr. Bain’s modification of the Mapleson D circuit, with fresh gas delivered via oxygen tubing arranged coaxially within standard corrugated respiratory tubing. Compared with the standard Mapleson D configuration, the Bain circuit was lightweight, easy to assemble, and conserved heat and moisture. It had a more economical fresh gas flow requirement during controlled ventilation and it was relatively straightforward to maintain normocarbia. With the support of Dr. Spoerel, Dr. Bain conducted physiologic studies showing the advantages of his breathing circuit and generated ample interest when he presented his early findings at the 1972 Canadian Anaesthetists’ Society meeting in Halifax. With its subsequent adoption across Canada and internationally, the Bain circuit elevated the global stature of the University of Western Ontario’s anesthesia department. Indeed, at Dr. Spoerel’s insistence as department chair, the Bain circuit became the default set-up for all anesthesia machines at the then-newly opened University Hospital in London.

For many years afterward, Dr. Bain conducted physiologic research using his breathing circuit. He was frequently invited to other institutions to lecture about its applications, even as technological advances led to the Bain circuit’s eventual supplantation by the circle system. Nevertheless, the Bain circuit remains commonly used in variable resource settings, and in pediatric and veterinary anesthesia.

In addition to his enthusiasm for anesthesiology, Dr. Bain maintained many varied interests. It is possible that, were he not persuaded by his father to study medicine, he might have gone on to a career in architecture. Built in 1967 from his original design, a stunning midcentury home in London still attests to his creativity and vision. Dr. Bain was also a discerning art collector, reflecting his deep appreciation for esthetics and personal expression. Nevertheless, most of all, he is remembered as a genuine and unpretentious individual, with tremendous love for his family and friends. Dr. Bain’s legacy endures not only through his groundbreaking contributions to anesthesiology but also through the lives he touched with his ingenuity, humility, and dedication.