Clots in the Lungs

One of the most deadly accidents that can befall the human circulatory system--as likely to kill quickly as a stroke or a heart attack--has no everyday English name. It is pulmonary embolism, in which the flow of used blood is blocked, nearly always by clots, in the pulmonary artery leading from the heart's lower right chamber to the lungs (see diagram). Medicine and surgery have been helpless to deal with severe cases of pulmonary embolism. Now a team of Houston doctors suggests that if victims can be operated upon promptly, a number may be saved with the aid of a heart-lung machine.

Most of the artery-blocking clots are formed naturally in inflamed veins in the lower part of the body, sometimes after childbirth. Others are the result of surgery. Such a case is described by Baylor University's Dr. Denton Cooley and colleagues in the A.M.A. Journal. A woman of 37 was sent home, apparently doing well, eleven days after a hysterectomy. Next morning, as she climbed out of the bathtub, she collapsed, gasping for breath and suffering intense pain in the chest. Back she went to Jefferson Davis Hospital, where doctors did everything possible to boost her blood pressure and reduce the risk of further clotting. She was failing fast, 40 hours after her embolism, when Surgeon Cooley recommended a daring operation to clean out the clots from her pulmonary artery and lungs.

The patient's chest was opened along the breastbone. Tubes slipped into both great veins led used blood out of her body to the heart-lung machine. Another tube fed it back into a leg artery. A clamp on the aorta helped to keep the heart and lungs virtually bloodless. Dr. Cooley slit open the main pulmonary artery, found nothing in it. But in the successively smaller branches and in the lungs themselves were at least 18 clots. Dr. Cooley pulled some out with forceps, extracted the others with a vacuum suction tube. He washed out the lungs and squeezed them flat to get the last clots out.

This took 15 minutes--more than four times as long as the body's blood flow can be safely stopped without a heart-lung machine. Then Dr. Cooley stitched up the artery and let normal blood flow resume. Immediately, the patient's blood pressure was a healthy 120 over 70. To protect her against the risk of renewed clotting, the great vein in her lower right flank was tied off. She went home in two weeks, and has remained well for months.

To benefit from the Cooley operation, most victims of pulmonary embolism will have to get, within a few hours, to a major center for heart surgery. So Dr. Cooley urges heart-lung surgeons to figure out ways of cutting down the time it takes to set up for an emergency operation.

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