The Michigan Heart

Surgeons and medical inventors who have been trying to perfect a mechanical substitute for the human heart, to be used while delicate surgery is performed on the heart itself, got a fillip of encouragement last week. Three doctors at Detroit's Harper Hospital reported in the A.M.A. Journal that they had used a mechanical substitute for the left side of a patient's heart and kept his circulation going this way for 50 minutes. The patient made a good recovery. If, as the three doctors believed, they had diverted the patient's entire blood flow, it was the first such case in medical history.*

Though several teams of mechanically minded surgeons have been working for years on substitute hearts, it was a group of newcomers in this kind of work who reported the latest advance. Dr. Forest Dewey Dodrill, 50, specialized in chest surgery until two years ago, when he threw himself into the heart-machine project. General Motors research engineers helped him perfect the pump. After experiments on dogs, the surgeons were ready for a human patient.

Six Rubber Pistons. In July, they found their volunteer: a man of 41 whose mitral valve (between the upper and lower quarters of the heart's left side) was not working right because of rheumatic-fever scars. His chest was opened. Through a vein leading from a lung, a tube was slipped into the upper left side of the heart. This drew blood out of the heart to the six-cylinder pump, where fingerlike rubber pistons boosted it on its way. From the pump another tube led the pulsing blood back to the patient's aorta, where it would normally be leaving the heart.

It happened that the patient's heart was so enlarged that Dr. Dodrill could not expose the mitral valve as he had hoped to do. He had to work "blind," with his finger in the heart, manipulating the valve flaps --a standard operation for this condition, performed regularly without a pump. The patient got along fine, and his valve now works better.

Did He or Didn't He? Dr. Dodrill and his colleagues believe that they got all the patient's blood out of the upper left side of his heart (their flowmeter indicated almost five quarts a minute passing through the pump). Other researchers doubt that it is possible to remove all the blood in this way. And. they argue, Dr. Dodrill has no proof that he was shunting it all aside and producing a "dry field" for operation, because he did not open the lower part of the heart.

The real answer to successful, all-out heart surgery is likely to be a device which will take over the work of both sides of the heart and the lungs as well. The "Michigan heart," as Harper officials call Dr. Dodrill's machine, is built like a V12 engine: the second bank of six cylinders can do the work of the heart's right side. There is also an oxygenator to pinch-hit for the lungs. The whole machine has been tested on dogs, but there must be a lot more testing done before it satisfies surgeons generally as a safe substitute for the human body's most vital organs.

* Other surgeons have tried similar techniques on patients who had no chance of surviving without the operation, and little chance even if it was successfully completed. None has lived. Some have survived after part of their blood flow was shunted through a pump.

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