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Critical Concept


two practical nurses, three aides, two orderlies, and one clerk. In fact, the emergence of ICUs stimulated the evolution of critical-care nursing. The American Association of Critical-Care Nurses was founded in 1969, and by the mid-1970s there were certification exams for critical-care nurses.

Patsy Ramsay Pilgrim, R.N., was a senior at the MHMH School of Nursing when she worked in Mosenthal's SCU in the 1950s. The unit didn't use younger students because Mosenthal believed that acutely ill patients required more mature and experienced care and that the SCU was a poor place to teach basic nursing skills. Pilgrim thrived on the intensity, however. She decided to specialize in critical- care nursing and worked in early intensive care units at other New Hampshire hospitals.

Critical-care nurses in those days were particularly adept at assessing the condition of patients. "We didn't have the equipment, [yet] we had assessment skills that were, I think, pretty exceptional," Pilgrim says. "We couldn't depend on a machine to tell us what blood pressures were or what a lot of vital signs were. You'd have to be more observant and be with the patient more. Today you can sit at a nursing station and you can get almost every vital statistic that you need . . . from a machine." Before retiring in 1998, Pilgrim was CEO of Weeks Memorial Hospital in Lancaster, N.H.

Over the years, many technological innovations were brought into ICUs. One early advance—the measurement of blood gases such as oxygen and carbon dioxide—played a role in physicians' ability to recognize and control respiratory failure.

In the early 1950s, "respiratory failure was not recognized as much of a problem," says John Lyons, M.D., who trained in surgery in the early 1960s at MHMH and later ran the ICU. Sometimes a patient might have a heart attack after surgery, and it would be considered "as heart

critical_conept

Sibley's sketches—wry views of the pandemonium that often prevailed in pre-ICU hospitals—were used in a traveling exhibit about the unit.

failure or a cardiac event," recalls Lyons, now an associate professor of anatomy. "But what really had been going on was that he hadn't been breathing adequately. So he was getting hypoxic—slowly, slowly, slowly, getting hypoxic, slowly building up carbon dioxide, which is acid, too, until such . . . a severe imbalance occurred in the body that the heart finally failed."

But until physicians began to measure blood gases, they had no way of knowing when patients were being deprived of oxygen. "The biggest surprise is how ignorant we were of this whole business of respiratory failure postoperatively," says Lyons.

Dartmouth played a role in the early development of devices to measure blood gases. DMS physiologist Ferdinand Kreuzer, M.D., who received funding in 1955 to study the diffusion of oxygen in thin films of hemoglobin, developed one of the first electrodes to measure blood oxygen. "It was a big, cumbersome thing," Lyons says. "It wasn't something that would be clinically useful. You might

get one blood oxygen every couple of days out of it." But other devices for measuring blood gases were being developed elsewhere, and by the 1960s blood gases were being measured routinely.

Soon there was another technological turning point. "ICUs really got going with the advent of mechanical ventilators," according to Margaret Parker, M.D., president of the national Society of Critical Care Medicine. Nowadays, respirators help a person breathe by pumping air into the lungs via an endotracheal tube that's snaked through the patient's mouth and down the trachea, or windpipe. But in the 1950s, endotracheal tubes were not well tolerated by patients.

"The ones they had were pretty rough," explains Naitove. Endotracheal tubes used to be made of rubber, whereas modern ones are made of flexible plastic that's not as irritating to the throat. "The way you gave endotracheal respiratory control was you put a tube down, and then you packed the pharynx with [wet] gauze so it wouldn't leak" air, he explains. "It was pretty crude stuff we had then."

Because endotracheal tubes were impractical for long-term use, physicians often performed tracheotomies. That entailed surgically cutting a hole through the patient's neck into the trachea and inserting a tube through which the person could breathe. The tube could then be attached to a ventilator.

But tracheostomy tubes would fill with mucus and had to be suctioned out on a regular basis—sometimes as often as every 15 minutes. In pre-SCU days, nurses might be running from bedside to bedside, to patients in different rooms and on different floors of the hospital, to keep up with the suctioning. One of Sibley's sketches used in the SCU exhibit depicted this challenge.

The precursors of today's ventilators were the iron lungs used to sustain polio


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