Welcome back to the tasty morsels of critical care podcast.
One would think that the term drowning should be relatively straightforward, however there have been a plethora of descriptions including wet drowning, dry drowning and near drowning. These have all been officially retired and the Utstein guidance on the matter describes drowning as “a process resulting in primary respiratory impairment from submersion or immersion in a liquid medium”. If you happen to have been immersed in a liquid medium with respiratory impairment but survived then the term non fatal drowning seems to be acceptable.
As a brief tangent, given that this is going to be a shorter than usual podcast, the “Utstein guidelines” refer to a 1990 ESC meeting regarding cardiac arrest at Utstein Abbey on the island of Klosteroy in Norway. Knowing that the significant output of Augustinian Abbeys is often excellent beer then I suspect that members of the ESC committee probably spent quite a lot of time immersed in a liquid medium themselves.
More usefully the pathophysiology of drowning could be described as follows:
- when under the water we sensibly engage in some voluntary breath holding, this in combination with the cold induces a reflex bradycardia and vasoconstriction
- As those of us who have
attempted to drown infants as medical treatmenttreated SVT in babies will attest to, this reflex is much stronger in tinies than adults
- The profound reflex in kiddos may be one of the reasons they have better outcomes than adults. They get cold before they drown and get cardiac arrest which is probably protective. (as opposed to have a cardiac arrest and then get cold which is the more common mechanism)
- once the breath holding is broken water will hit the cords and you might get some laryngospasm but eventually water enters the lungs
- despite being physiologically interesting there does not seem to be any substantial difference in salt vs fresh water drowning
We often get excited about the perceived filth of the water as an indication for antimicrobials but in reality all outdoor water sources that you might drown in will have bugs in it. Pneumonia will occur in about 15% and perhaps one bug to remember would be aeromonas.
Treatment is pretty much as expected in a cardiac arrest scenario but it would seem prudent to pay rather more attention to the airway than than the pads. There may be a role for early bronchoscopy to remove debris or more interestingly to acquire images for your next NEJM publication showing the world’s first sea horse in a bronchus.
Of note Oh’s Manual quotes a 45% survival to discharge with cardiac arrest from drowning which is markedly higher than other forms of cardiac arrest but I suspect this refers to the swimmer witnessed to get into trouble and is quickly removed to shore.