There has recently been an interesting article published in the Critical care journal. The effect of treatment with vasopressin during sepsis has been investigated.
Vasopressin
First a bit of background. One of the problems during sepsis is leakage of plasma from the blood vessels which leads to a low blood pressure. Vasopressin is of interest for two reasons. Firstly it is an anti-diuretic, a fancy way of saying it makes you urinate less, and so you loose less water. Secondly it is a vasoconstrictor, it narrows the blood vessels, which means you need less fluid to maintain a pressure. Think of it as pinching the end of a garden hose.
Use in practice
From the above it would be reasonable to think it may well be useful in sepsis. Unfortunately it is not without problems as this recent article demonstrates. Narrowing the blood vessels reduces the amount of blood which can flow. If the blood flow is reduced too far then the organs won’t get the nutrients and oxygen they need to function and they will be injured.
The article claims that blood flow to the pancreas and the kidneys, which are frequently damaged during sepsis, is reduced. No treatment is perfect and it may be that vasopressin still has a use in the treatment of sepsis but it should be used with caution.
Don’t forget to take a look at the article. It is another one with open access which is great.
A recent paper has been published in which mice with severe sepsis when treated with EGCG, the major antioxidant in green tea, had a significantly lower death rate than controls. Initially I had dismissed it as all hype but on closer examination there may be something to it.
Why should we be sceptical?
Before I get into why this result is potentially interesting I’ll explain why I was (and you should be) initially sceptical. There have been a wide variety of compounds found to be amazingly successful in treating sepsis in animal models when administered prior to the onset of sepsis. Despite this out of 20 clinical trials (involving 10,000 patients) only 5 treatments have been shown to work. Only 2 of the 5 involved medicinal agents. I’ll probably go into more detail on this in a future post but the take home message here is that positive results in animal studies rarely transfer wel to humans.
Reasons for interest
- The dose of EGCG was sensible. A significant increase in survival was seen with 4 mg/kg bodyweight. A cup of green tea contains between 15 and 50 mg so working from my weight (90 kg) it would be equivalent to approx. 11 cups of green tea.
- EGCG was administered after the onset of sepsis. A problem with previous studies has been that a compound is shown to be effective if administered before onset of sepsis but not afterwards. In the clinic administering a compound before sepsis isn’t possible so these compounds have been of no use.
This is a very preliminary study but it is undoubtedly potentially interesting.
Thanks to eatingfabulous.com for prompting me to take a second look at this.
The paper is freely available. Hooray!