The rule of threes defines how long we can live without four necessities:
- Three minutes without air
- Three hours without shelter in a harsh environment
- Three days without water
- Three weeks without food
Influenza can make number 1 on that list a challenge.
Air is 78% Nitrogen and 21% Oxygen. We need that Oxygen to live. We take it into our bodies every time we inhale. It travels to our lungs and is then transferred to blood. Red blood cells carry the oxygen to our cells which require it for essential functions.
What happens if our lungs are no longer able to transfer oxygen to our blood? We are in immediate trouble.
The new H1N1 virus can damage our lungs in different ways. In some cases, using a mechanical ventilator to help the patient breathe has been necessary. However, even this step has not been sufficient in some severely ill patients.
In this case, a special technique has been used to deliver Oxygen directly to the patients blood: extracorporeal membrane oxygenation (ECMO). The machine used to deliver ECMO was initially developed for premature babies whose lungs may not have developed sufficiently when they were delivered. However, ECMO has been adapted to be used in adults in extreme cases. And, unfortunately, with the new H1N1 virus, there are lots of extreme cases.
From JAMA, October 12, 2009:
The spread of the virus [H1N1] to Australia and New Zealand was also associated with a large number of patients admitted to intensive care units (ICUs) across both countries. A proportion of these patients presented with, or developed, severe acute respiratory distress syndrome (ARDS). In some severe cases, extracorporeal membrane oxygenation (ECMO) was commenced for the treatment of refactory hypoxemia, hypercapnia, or both, which occurred despite mechanical ventilation and rescue ARDS therapies.
There have been both anecdotal reports and explicit studies of the effectiveness of ECMO in the treatment of respiratory disorders associated with pandemic flu.
From Medical News Today, September 16, 2009:
Of those referred for consideration of ECMO, 63 percent survived six months without disability compared to 47 percent of those who were assigned to conventional management.
Although it is good to know that survival in severe cases can be improved from 47 to 63% with ECMO, there’s a problem. Lots of people are likely to need ECMO, soon. And we probably do not have enough of the necessary machines and trained personnel to treat everyone who would benefit.
So, once again, we will need to play Lifeboat in the ICU.
Extracorporeal Membrane Oxygenation for 2009 Influenza A(H1N1) Acute Respiratory Distress Syndrome. Journal of the American Medical Association, October 12, 2009.