The Enigmatic Learning Curve

The learning curve is no stranger to individuals involved in learning surgical techniques, and can be painfully obvious to those involved in the training. Yet, there is one aspect of the learning curve that has eluded me for many years. I cannot identify what I learned or taught exactly with pinpoint accuracy to come off that steep slope. Sometimes it is not an exact and precise skill, but rather time and repetition alone.

When I was a first-year surgical resident assigned to the laboratory, I was given the task of testing our new heart-lung machine and preparing it for human use. It was a direct copy of the DeWall/Lillehei bubble oxygenator, which had been successfully used at Minnesota. Since we had experience and success with total body hypothermia and up to 10 minutes of circulatory arrest for cardiac surgery, my mentor, Dr. Peter V. Moulder, charged me with the task of only performing complete heart-lung bypass for 15 minutes and obtaining a surviving healthy dog. No cardiac procedure was performed but the chest was opened for cannulation. I was involved with other surgical experiments and operated nearly every day on one project or another, but the need for a heart-lung (H-L) machine clinically took precedence early. Anesthetizing, intubating, placing monitoring lines, ventilating, doing a thoracotomy, even cannulation all were rapidly mastered. Running the H-L machine was not challenging. Controlling oxygen flow and blood flow were the main concerns. Many dogs were sacrificed, including some used strictly as blood donors. Weeks ran into months and yet no survivors of this seemingly straightforward task! No one could pinpoint a problem with our preparation or our performance. Finally, someone returned from Texas where some clinical success was well known, and had noted the absence of an arterial filter in their H-L circuit. So the very next dog was done without a filter, and it was our first survivor! Eureka! The stumbling block was identified, and we could now proceed to the OR. When this news was given to Dr. Moulder, he shuddered and said no human being will be perfused without an arterial filter. So we put it back into the circuit, and the next dog survived as well! The enigma of the learning curve. I don't know to this day (45 years later) what it was that made the difference, but I did come to respect the learning curve (almost to a fault).

A few years later when I was a junior attending, I felt limited in my knowledge and experience, but had the opportunity to travel, observe and learn more about heart surgery.

I spent 6 months at Hammersmith Hospital with Professor Bentall and Mr. Cleland. This gave me a chance to visit many other centers in Great Britain and on the continent. The next 6 months I was generously given a fellowship at the Mayo Clinic to work with Dr. John Kirklin. His intellect, knowledge, skill, drive, dogged pursuit of truth, honesty, collegiality, precision, meticulous attention to detail, and desire to improve the field of heart surgery left an indelible mark on my subsequent professional life. His surgical approach and results were so far advanced compared to others I had observed that I patterned my practice as precisely as I could. I took voluminous notes after every different procedure, including steps, sutures, instruments, position of people, pump, wash basin, and, of course, technique. When I returned to Chicago, I was a Kirklin clone. I also was so well aware of the enigma of the learning curve that I could not evaluate what exactly was important. I even incorporated the washbasin ritual into my practice. Whenever his gloves became bloody, Dr. Kirklin would turn to the washbasin to rinse them. And occasionally in the middle of the case he would dip his hands in the cool basin briefly and obviously ponder some important issue. Needless to say, I would dip briefly at some point in the operation even without something to ponder. The power of the enigma of the learning curve was thus honored!