Brett
The fluid could be lymph, which is the body's healing itself with lymphocytes. That wouldn't be an uncommon thing, & natural, with draining it to keep them from drowning, as it were. The drug-induced comas may be morphine, which reduce the respiratory rate, which with the injury, would be a good thing, to reduce the lung's workload, so-to-speak. There may be cause to worry, but not too alarming, so just pray for them, & the doctors...