Quote Originally Posted by jmr_1019 View Post
You mean entering the bloodstream doc? Sure you can have pulmonary aspiration where water (or foreign material) enters the respiratory system but how does it exactly enter the blood vessel wall from the lungs? Isn't it respiratory aspiration the main cause for concern?
I deleted my original post because the thread was about drinking sea water, not drowning. However, since you ask, when seawater is aspirated into the lungs it actually draws blood out of the bloodstream across the membrane between blood vessels and the lung air sacs (alveoli). If freshwater is aspirated, it enters the bloodstream across the same membrane. The effect is the same, lack of oxygen. (The membrane between the alveolus and the blood vessel / capillary is microscopically thin. The total surface area for gas exchange - oxygen and carbon dioxide - is the size of a tennis court).
What I also said originally is that of the several hundred deaths each year from immersion in the UK, a proportion die from cardiac arrest before there is time to aspirate or swallow water, due to the coldness of the water. At post mortem examination in these circumstances little or no fluid is found in the lungs or stomach.