Swine Flu Can Move Quickly to Severe Illness

MONDAY Oct. 12, 2009 -- Canadian and Mexican intensive care units were swamped with patients who rapidly became critically ill with H1N1 flu this past spring and summer, new reports find.

Many of these patients were relatively healthy adolescents and young adults who needed to be treated in an intensive care unit (ICU) within a day or two of being admitted to the hospital, note doctors from both countries. Many patients required mechanical ventilators, say the reports, slated to be published in the Nov. 4 issue of the Journal of the American Medical Association.

The papers, coupled with another report released last week that detailed the impact of the pandemic on ICUs in Australia and New Zealand, indicate the need for the United States and other countries to prepare carefully for what very well could be an escalating number of hospitalized patients as the pandemic continues, experts said.

"These people were not just a little bit ill. They were spectacularly ill," said Dr. Anand Kumar, the Canadian lead author of one of the JAMA studies. "To see 40 patients like this simultaneously in the ICU, all struggling for their lives, all in the space of a few weeks -- that's really unusual."

"Without preparation, there would be some chance that some areas would be overwhelmed," Kumar said. "As long as we prepare, it should be handled."

Kumar, an associate professor in critical care and infectious disease at the University of Manitoba, Winnipeg, believes that "the value of this paper is to alert and sharpen the thinking of the authorities in terms of making sure that we do have strategies in place to mitigate what's likely to happen."

Another expert worried that many U.S. hospitals might not be up to the challenge.

"The concern is that we would have difficulty meeting the demand because our health-care system operates near capacity most of the time, and there's not a lot of excess capacity in the system," said Dr. John J. Treanor, a professor of medicine and of microbiology and immunology at the University of Rochester Medical Center. "I think there's a cause for alarm -- though not undue alarm -- because one would predict a pretty intense flu season and there will be a lot of demand placed on emergency rooms and hospitals."

Indications are that, overall, most cases of H1N1 flu remain mild. But with more people getting sick overall, the number falling severely ill will swell.

The types of people hospitalized in Canada, Mexico and Australia are consistent with U.S. trends seen so far.

"What all of them have in common is the burden was seen primarily in older adolescents and young adults as opposed to the elderly, which is what is typically seen with seasonal influenza," noted Dr. Nathan Litman, director of pediatrics and chief of pediatric infectious diseases at the Children's Hospital at Montefiore Medical Center in New York City.

The average age of the 168 confirmed or probable H1N1 swine flu cases in the Canadian study was 32.3 years. A large proportion was female (113), 50 were children and 43 were aboriginal. Although average time from the onset of flu symptoms to hospitalization was four days, the patients' condition typically deteriorated so quickly upon admission that they were sent to an ICU within 48 hours. More than 80 percent of these very sick individuals needed mechanical ventilation, many experienced shock or organ failure and, by one month after admission, 14.3 percent of them had died.

Although many patients had other health conditions, including obesity, these conditions tended not to be severe and included being smokers, being overweight or having high blood pressure, Kumar said.

This pattern of the virus affecting younger, healthy people is similar to that seen in the deadly 1918 Spanish pandemic, the authors noted.

In a second study, researchers in Mexico -- where H1N1 first arose in the spring -- found critical illness in 58 of 899 total patients admitted to the hospital. Here the mean age was older (44 years) but still relatively young. About one-quarter were obese. Again, patients moved from the hospital to the ICU quickly, and most received mechanical ventilation. Within two months of admission, 41.4 percent of the critically ill patients had died, four of them while waiting for ICU beds.

Overall, prompt and proper care did save most lives, the researchers stressed.

A final paper, this one out of New Zealand and Australia, found a rise in the use of a system called extracorporeal membrane oxygenation, which provides extra oxygen to a patient's blood. The survival rate for patients critically ill from H1N1 flu was high in this group.

After reading the reports, Dr. Tamara Kuittinen, an emergency physician with Lenox Hill Hospital in New York City, said that she will be more inclined to err on the side of caution, especially if patients have one or more other health conditions.

"If it were borderline, I would admit [the patient to the hospital] right off the bat," Kuittinen said. She also said she would be advising outpatients to monitor their conditions closely and seek more medical care if symptoms worsen or don't get better.

But the experience observed in the spring might not be as dire this fall, one expert added.

"We're all hoping that a substantial portion of the population in fact was infected [earlier this year], and, if so, they will be immune and they will not get infected," said Dr. Edward Walsh, professor of medicine at the University of Rochester Medical Center and chief of infectious diseases at Rochester General Hospital. "That will reduce the burden, the pool of susceptible people. It will also reduce the potential transmission from person to person."

And the previous experiences that are now coming to light form a strong argument for getting the swine flu vaccine, Treanor added.

More information

The U.S. Centers for Disease Control and Prevention has much more on H1N1 influenza.

Posted: October 2009


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