Operating Under Pressure

The high pressure with which deep-sea divers and tunnel workers must contend has always been a source of danger, but now physicians and surgeons on both sides of the Atlantic are deliberately subjecting their patients to deep-sea pressures to save their lives. As testament to the success of this paradoxical treatment, "blue babies" are turning a healthy pink even before the end of operations. Seemingly hopeless cases of carbon monoxide poisoning and of gas gangrene (a deadly infection) are pulling through.

The Sooner the Better. One of the first of the pressure pioneers, Amsterdam's Dr. Ite Boerema (pronounced Boor-uh-muh), did his earliest work with his smallest patients--"blue babies," whose red blood cells were being starved of oxygen. Born with defects in the heart or its surround ing great vessels, such children are so frail that drastic surgery can kill them. The sooner they can have a corrective operation, the better. Dr. Boerema reasoned that if he could operate under double or triple atmospheric pressure and make the youngsters breathe pure oxygen through a mask, their red cells would pick up more oxygen and keep their fragile systems working better so that surgery would be safer.

Two years ago, Dr. Boerema and his colleagues began operating on youngsters suffering from one of the commonest forms of blue-baby disorder--Pallet's tetralogy, a set of four serious heart defects which nearly always occur together. All the children were under five; they had only about 70% of normal oxygen in their red cells, and they were too ill to risk the heroic surgery that would correct all their heart defects. Dr. Boerema wanted to do a palliative operation, after which a final operation could await a few more years of growth and added strength.

Dr. Boerema ruled out the use of a heart-lung machine because that, too, seemed dangerously drastic. Instead, he operated in a chamber at triple atmospheric pressure. With the children breathing 100% oxygen, instead of air with its 20% oxygen, they were getting 15 times the normal supply. They turned pink at once. Dr. Boerema clamped off the great vessels around their hearts to shut off circulation. Unhurriedly, he made a connection between two arteries. Thanks to the oxygen drenching, the children showed no ill effects from the blood-flow shut down, and emerged from the operations with oxygen concentrations in their blood ranging from 92% to 96% of normal.

Deceptively Simple. Success was dramatic. But progress from theory to high-pressure operating room had been no easy matter. Before he could risk his new procedure on children, Dr. Boerema had experimented widely with the effects of high pressure. In the process, he discovered that oxygen drenching was good for victims of gas gangrene, which is caused by a bacillus closely related to that of tetanus. When he figured out the explanation, he realized that he had done more than develop a new form of therapy; at last he knew enough about the effects of high pressure to start his operations.

The principle is deceptively simple. Little oxygen is normally dissolved in the fluid portion of the blood, which relies on the hemoglobin in its red cells to carry oxygen, in a loosely combined form, to all the body's tissues. Dr. Boerema learned from animal experiments and his gas gangrene patients that it matters little during an operation whether the amount of oxygen carried by hemoglobin is increased: what counts is that under high pressure the watery part of the blood dissolves a considerable amount of gas. In Dr. Boerema's operations, that gas is life-saving oxygen. And the operation fixes up the children's circulation so that later the hemoglobin itself can do its job better.

Dry Dive. At Children's Hospital Medical Center in Boston, where surgery on children's hearts was born under the meticulous scalpel of Dr. Robert E. Gross in 1938, Dr. William F. Bernhard wanted to try the Boerema technique. First he went to Newport to ask the Navy for an old compression chamber. The Navy wasted no time telling him to go home: just the tank he wanted had been gathering dust since 1934 in a Harvard lab, only a few yards from Children's Hospital.

Last week Dr. Bernhard told the Society of University Surgeons meeting in Seattle that four blue children have had operations in the chamber. Two died of complications. But two who were suffering from one of the most surgically forbidding of all congenital defects, transposition of the great vessels (aorta and pulmonary artery), are doing well after palliative operations.

Dr. Bernhard works in an 8 ft. by 10 ft. compartment of the chamber, with an assistant surgeon, an anesthesiologist and a nurse. After an operation, the patient and surgical team are decompressed even more carefully than current Navy practice calls for; the process of surfacing from a "dry dive'' that reaches 80 ft., or almost 3 1/2 times normal atmospheric pressure (about 50 Ibs. per sq. in.), is stretched out over an hour. Says Surgeon Gross: "Operating under pressure gives us one golden hour to achieve results impossible under normal conditions. We are going to hear a lot more about this technique in the next three or four years."

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