Here's a quote from the 60s NASA study on testing rapid decompression of dogs for over a minute: https://www.reliasmedia.com/articles/4602-evaluation-and-management-of-patients-with-blast-injuries-in-the-ed
During recompression to higher pressures,
the subcutaneous gases were, of course, also
recompressed and the animals quickly and
dramatically deflated to their normal appearance, still remaining, however, in an obvious state of flaccid paralysis, unconsciousness,
and apnea. This deflation process appeared to
begin rather gradually with the onset of recompression. At 25 to 30 mm. Hg absolute, deflation became more rapid ; at approximately
70 mm. Hg the animals appeared to have returned to their normal size. At 45 to 50 mm.
Hg, however, a major portion of the deflation
is complete, suggesting that water vapor is
probably the predominant gas concerned with
the excessive distention of the animals. The
exact pressures at which the deflation process
and the condensation of water vapor occurred
was influenced, in part at least, by the subcutaneous and deep body temperatures which,
in turn, were probably affected by the duration
of the low pressure exposures and the evaporative cooling of the body surfaces.
The rapidity of recovery during or after
recompression was generally dependent on the
duration of the low pressure exposure, the rate
of recompression, and on whether or not the
animals were recompressed with oxygen or air.
As might well be expected, the shorter the
exposure time and the faster the recompression
with oxygen, the more rapid and less complicated was the recovery period. Animals that
were exposed to the low pressure for 90 seconds
or less often began to breathe spontaneously
during the recompression to ground level.
When the exposures to the reduced pressure
were longer than 90 seconds, the depressed state
of the animals was intensified and apnea persisted for a prolonged period of time after
recompression. Under these conditions, when
first examined at ground level, the animals
were usually apneic with variations in heart
rate ranging from bradycardia to tachycardia.
They remained apneic for varying periods of
time, but spontaneous respiration always began
in less than 2 to 3 minutes, provided there was
a heartbeat. Otherwise, when no heartbeat
was detectable, the animals invariably failed to
survive. During the course of recovery, both
the heart rate and respiratory frequency increased steadily for the first 2 to 5 minutes.
Some of the animals exhibited a state of decerebrate spasticity when stimulated by being
touched or handled. Most of the animals
started purposeful movements of the extremities and head within 10 to 15 minutes and next
progressed to a stage showing disorientation,
with staggering and apparent blindness. During this time, coordinated control and strength
in the hind legs seemed to return much more
slowly than in the forelimbs. By the end of
30 minutes, none of the animals exhibited objective neurologic abnormalities ; nevertheless,
they appeared to be in a state of extreme
fatigue and exhaustion and were very lethargic.
The apparent blindness seemed to abate by
the end of the 30th minute of recovery. Those
that were exposed to the low pressure for
longer than 60 seconds excreted, after recompression to ground level, an excessively large
amount of clear, saliva-like fluid from the
mouth; moist, basal rales were audible, suggesting pulmonary edema. By the end of 24
hours, the animals spontaneously cleared themselves of the rales and edema and appeared to
have normal respiratory function and behavior.
Some of the dogs were decompressed over 0.2 seconds,, most were over 1 second, all were to about 1mm Hg. There is no special mention of the damage for the faster decompressions. With 120 sec exposure, fatality rate was 15%, with 180sec it was 80%.
At that rate, and from figure 4 of this article Carey Gregory kindly found, it seems explosive decompression is not fast enough to warrant concern compared to the blast wave. Thermobaric warheads create a vacuum for some amount of time, but even then I would only worry about it somewhat worsening existing conditions from the blast.
In various literature about blast injuries, practically no mention is made of depressurization as a factor, as well. So it seems what I heard about it was just a rumour, likely inspired by the myth of astronauts exploding in space.
I hope this was interesting to read.
