Archive for January, 2010

It's respiratory syncytial virus (RSV) time again

January 25, 2010  |  General  |  No Comments

I’ve written before (here and here) about the reliable winter time arrival of RSV. This virus is the most common cause of pneumonia and bronchiolitis in children under six months of age. To scientists, RSV is a fascinating virus with several unique properties.

One of these is its behavior in the population. During its annual visitation, RSV is everywhere. Then it suddenly vanishes. There are exceptions to everything in medicine — I have seen sporadic cases during the off-months — but generally RSV arrives with a bang in mid-winter and then leaves suddenly in the spring. It is the only virus that consistently and reliably causes an epidemic every single year. Not even influenza does that. However, RSV epidemics may still have some regional variability. For example, often one city will have a much more severe epidemic than do others in other regions of the country.

Another aspect of RSV that interests medical scientists is how poor a job our immune systems do in fighting it off. Virtually all children are infected with RSV during the first year of life. Not only that, all of us are reinfected multiple times during our lives. Attempts at devising a vaccine for RSV have all been unsuccessful. In fact, early versions of an experimental vaccine seemed to make the disease worse in some infants, raising the possibility that some aspect of our immune response to the virus actually contributes to the symptoms.

RSV has a high attack rate — the term scientists use for the chances that a susceptible person will get the infection if exposed to it. That, plus our generally poor defenses against it, explain the frequent epidemics.

RSV is generally not a serious illness, but for some children it can be life-threatening. These children are very small infants, especially those born prematurely, and those with underlying problems with their lungs or their hearts. For those infants we have a monthly shot that helps reduce the severity of RSV when they get it, and may even prevent a few cases, but this is not ideal.

Since RSV cannot be prevented, the best thing a parent can do is try to postpone it. That is, if you have a newborn infant in the height of RSV season, try to minimize exposure of your child to people with cold symptoms, especially toddlers. And for those who do handle your infant, have them wash their hands first.

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It’s respiratory syncytial virus (RSV) time again

January 25, 2010  |  General  |  No Comments

I’ve written before (here and here) about the reliable winter time arrival of RSV. This virus is the most common cause of pneumonia and bronchiolitis in children under six months of age. To scientists, RSV is a fascinating virus with several unique properties.

One of these is its behavior in the population. During its annual visitation, RSV is everywhere. Then it suddenly vanishes. There are exceptions to everything in medicine — I have seen sporadic cases during the off-months — but generally RSV arrives with a bang in mid-winter and then leaves suddenly in the spring. It is the only virus that consistently and reliably causes an epidemic every single year. Not even influenza does that. However, RSV epidemics may still have some regional variability. For example, often one city will have a much more severe epidemic than do others in other regions of the country.

Another aspect of RSV that interests medical scientists is how poor a job our immune systems do in fighting it off. Virtually all children are infected with RSV during the first year of life. Not only that, all of us are reinfected multiple times during our lives. Attempts at devising a vaccine for RSV have all been unsuccessful. In fact, early versions of an experimental vaccine seemed to make the disease worse in some infants, raising the possibility that some aspect of our immune response to the virus actually contributes to the symptoms.

RSV has a high attack rate — the term scientists use for the chances that a susceptible person will get the infection if exposed to it. That, plus our generally poor defenses against it, explain the frequent epidemics.

RSV is generally not a serious illness, but for some children it can be life-threatening. These children are very small infants, especially those born prematurely, and those with underlying problems with their lungs or their hearts. For those infants we have a monthly shot that helps reduce the severity of RSV when they get it, and may even prevent a few cases, but this is not ideal.

Since RSV cannot be prevented, the best thing a parent can do is try to postpone it. That is, if you have a newborn infant in the height of RSV season, try to minimize exposure of your child to people with cold symptoms, especially toddlers. And for those who do handle your infant, have them wash their hands first.

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How will the healthcare reform bill affect the PICU?

January 15, 2010  |  General  |  No Comments

By now everybody knows that the Senate passed a healthcare reform bill last week. The House passed such a bill last month. The bills differ in important respects, and of course it is still unclear if the two bills will be reconciled in conference committee to produce a bill that both houses will pass. If a final conference bill does pass, it will have ground-breaking effects on medical care. What might change in the PICU?

My first-blush answer is that it will have important effects for me, my colleagues, and our patients, but not so much as it might for other aspects of medical practice. Why do I say that? First, look at where our current healthcare dollars come from (source is here):

Private insurance: 35%
Medicare: 19%
Medicaid and SCHIP: 15%
Other public funds: 12%
Other private funds: 7%
Out-of-pocket: 12%

These figures are for the entire system. As I’ve written before, the PICU is different — very different. Around half of children in the PICU already are covered by Medicaid, the joint federal/state program for children of poor families. This startling statistic is a reflection of the fact that poor children are far more likely than are affluent children to end up in the PICU.

But even though half the children in America’s PICUs are on Medicaid, half are not, and the healthcare reform bill can have a major impact on them, especially those from families who are presently uninsured. A PICU bill can bankrupt those families. This bill will reduce the number of times that will happen, and I think that is a good thing.

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H1N1 flu — report from the trenches of one PICU

January 10, 2010  |  General  |  No Comments

The H1N1 strain of influenza — the “swine flu” — has gotten a lot of headlines this past year. You can find a summary of matters during the first half of 2009 here. That report studied 272 patients who were sick enough to be admitted to the hospital. Of these, 25% needed to be in the ICU. From my perspective, the interesting part was that nearly half were children; unlike usual influenza epidemics, only 5% were older than 65.

I didn’t see any severe cases of H1N1 until this past fall, but then I began to see quite a few of them. Of these, two were so severe that they required prolonged treatment with a mechanical ventilator, a breathing machine. Another child in our region was so severely ill that he required treatment with the most extreme kind of respiratory support, something called extracorporeal membrane oxygenation (ECMO). This machine bypasses the lungs entirely and uses a machine to get oxygen directly into the child’s bloodstream. Using ECMO is a complicated endeavor, one with high risks and high mortality. But sometimes it is all we have to offer.

My conclusion on the H1N1 flu is that it was every bit as severe as the experts predicted. Although the mortality was not anywhere near as bad as the great epidemic of 1918, we also have means of ICU support that physicians didn’t have back then. This year’s flu, like that of 1918, also seemed to affect the very young to a degree I haven’t seen before. To me, the massive campaign to vaccinate as many as possible was justified. Of course we don’t know if it helped reign in the epidemic thus far, but I think it probably has.

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What works better for killing influenza virus — soap and water or hand sanitizer

January 2, 2010  |  General  |  No Comments

Since the beginning of the H1N1 (swine flu) influenza epidemic bottles of commercial hand sanitizer have been flying off the shelves. They’re everywhere in my son’s elementary school, for example, and I’ve seen them sitting on the counter and available for customer use in stores and banks. Is that gel worth it? Does simply washing your hands work just as well?

That question has been studied, quite directly, here. The investigators tested twenty volunteers who had been vaccinated against H1N1 influenza and who had had a blood test that documented that they were immune to the infection. So they couldn’t get sick from the virus. These volunteers then had live flu virus put all over their hands, after which they washed them either with soap and water or one of several hand sanitizers. The investigators then tried to recover live virus from the volunteers’ hands, and compared the results to how much virus they could obtain from the hands of volunteers who did not do anything except air-dry their hands.

The results showed that all methods dramatically decreased the amount of virus on the hands. Seventy percent of volunteers who did not wash with anything still had virus on their hands even an hour later. All of the hand cleaning techniques worked very well, but simple soap and water actually worked the best. So sanitizer is fine if you haven’t got a sink around, but wash your hands the old fashioned way if you do.

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