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July 12, 2012

Optimize ICU services, critical care medicine professor urges

Derek Angus

Derek Angus

While the current intensive care delivery system has yielded significant gains in saving lives, reorganization is needed to optimize resources, said medical school faculty member Derek Angus. He delivered a June 26 lecture commemorating his appointment as the Dr. Mitchell P. Fink Chair in Critical Care Medicine.

Tiered care models and regionalization should be considered in order for lifesaving advances in intensive care to best serve all, he said, citing the variability in availability of intensive care as well as the prospect of a future with more — and sicker — patients, higher costs and fewer resources to care for them.

In the United States, there are some 5.7 million adult ICU admissions each year, Angus said. That equates to an average of 1.7 ICU admissions per lifetime.

Who gets admitted to the ICU? Typically it’s those who are at risk of, or who have developed acute organ dysfunction, Angus said.

He compared the effect of critical illness on the body with a threat to a nation. A traumatic injury, infection or bleeding ulcer is the human equivalent of a crisis like a bomb or air raid, invoking a response aimed at assessing, containing and eliminating the threat.

While authorities may deploy police or the bomb squad, the human body deploys inflammatory cells, undertakes systemic endocrine and vascular changes and changes in circulating proteins in response, he said.

What’s more, the crisis may escalate, generating a complex set of responses with multiple skirmishes taking place.

“If the threat is not contained, you get much more massive redirection of resources, you get damage from the invader, you have a lot of collateral damage,” he said.

In a national crisis, escalation may result in a shift to a wartime economy with a complete disruption of normal services. In humans, the equivalent includes an overwhelming activation of immune response and physiologic stress resulting in systemic collateral damage.

The body’s response to sepsis or trauma or shock can lead to an inflammatory response that can progress to tissue damage, organ failure or even death.

Acute organ dysfunction can affect the neurologic, cardiovascular, renal, hematologic, respiratory and gastrointestinal systems, Angus said.

More than one-third of ICU admissions are for post-operative care; 19 percent are attributed to cardiac events. Other causes include pneumonia, trauma and burns, acute neurologic events (such as strokes), infections and gastrointestinal bleeding.

Classic ICU syndromes include severe sepsis, which is an infection accompanied by acute organ dysfunction; acute respiratory distress syndrome (ARDS), characterized by lung dysfunction, and multisystem organ failure, a complex condition involving two or more organs.

“All of these syndromes share in common that they were essentially 100 percent lethal before the advent of modern intensive care,” Angus said, adding that, even with intensive care, many of these syndromes result in hospital mortality rates greater than 25 percent.

“A one in four chance of being dead within three or four weeks of diagnosis — these are still pretty bad syndromes,” Angus said. “In fact there is no cancer that has as severe a prognosis as these ICU syndromes.”

And, unlike TV or movies where ICU patients typically are young trauma victims, real-life ICU care more often is centered on older patients. “These are people who often have significant frailty and underlying conditions,” Angus noted.

While one in five patients die in the ICU or shortly after an ICU admission, there also are growing numbers of survivors — about 5 million, or roughly 2 percent of the U.S. population — each year, Angus said.

Survival carries its own risks, he noted, citing studies that showed higher rates of long-term cognitive impairment and higher mortality rates in patients who had survived sepsis — even five years after the episode. Similarly, other research showed reduced quality of life and higher rates of death in patients who had survived ARDS.

“We’re not actually sure why patients who appear to have survived have these lingering trajectories,” he said, adding that some studies have implicated ongoing inflammation as among the culprits contributing to the higher morbidity and mortality.

In addition to developing effective therapies to modulate the body’s responses and promoting longterm recovery, other improvements to ICU delivery, such as optimizing organization and staffing, are needed, he said.

Angus said half of the nation’s 70,000 ICU beds are in hospitals of 300 beds or less, adding that the number of intensivists varies from 1.8 to 13 per 100,000 people in the United States.

Only one in three patients in the ICU are seen by an intensive care physician, he said, noting that the majority of intensivists are in large hospitals.

Aging baby boomers are expected to drive demand for intensivists higher in the coming decades, but the numbers of intensivists is expected to remain flat. In a 2000 study, Angus projected that the demand for intensivists will result in a 35 percent shortfall in specialist hours by 2030.

What can be done? Options include doing nothing and watching mortality rise as services are less available; expanding training slots, or sharing ICU care with other specialists such as hospitalists.

Another option is to promote remote intensivist care, either through the services of physician extenders (such as nurse practitioners or physician assistants) or via telemedicine.

While those may be part of the solution, Angus suggested larger-scale programmatic changes to implement a regional model in which experts could be concentrated in high-level ICU centers where the sickest patients would be treated.

—Kimberly K. Barlow

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