Evening star. [volume] (Washington, D.C.) 1854-1972, 1906-10-27
CAUSE OF CAIssoN DISEASE.
The "Bends" Which Afaicts Men
Working in Compressed Air.

From the Literary Digest.
Owing to the number Of engineering
works that are now being prosecuted in and
around New York with the aid of COM
pressed air, public notice has been espe-
ctally directed to the so-called "caisson dis
ease,' or the bends as 1t has been popu-
lariy named. which is apt to attack men
working In an atmosphere under pressure
1t Is now quite certain that the trouble Is
caused, not by the pressure itself but by
Its sudden relief on passage too quickly into
the open air. The following explanation,
quoted from the Evening Post in Casters
Magazine (October), puts the matter
clearly:
Recent autopsies performed upon human
beings killed by caisson disease Indicate
that the bends Is caused by air bubbles in
the blood as those bubbles have been found
In the heart. blood vessels and various It's
very harmless. and it may be asked how
they are capable Of producing such profound
disturbances and often death.
Ihe realization of the serious conse-
quences OF air in the circulating blood is as
old as Galen, and the danger of allowing
the air to enter certain veins in the course
OF surgical operations is guarded against
by modern surgeons. If by any chance air
as a bubble-that is, in contrast to absorbed
or dissolved airs in the circulating blood
stream. it acts like a foreign body The
bubble may pass along for distance, but
at some point 1t will block the circulation
Of the blood by obstructing q small artery
Should the air bubble lodge in a vessel Of
the brain through which the blood passes to
nourish some important center, as that
which controls respiration, then the brain
center would at once cease to function. The
individual stops breathing and death ensues.
The same Is true of an air embolus in the
heart. But II the circulation to centers
that are not vital is impeded the other
symptoms Of the disease are manifested.
pains In the limbs and joints and various
degrees Of paralysis
I'm the less severe forms of bends COM
plete recovery of health is not unusual be-
cause in the course of a little time the air
Is reabsorbed into the tissue fluids, and
those parts which have suffered as a result
of starvation in having the blood stream
cut of from them are again restored to nor
NAL Only in the case of the nervous sys-
tenn, where regeneration of injured tissue Is
especially difficult. do permanent injuries
result.
IF the man who has been In a caisson
for several hours under pressure of two
| or more atmOspheres passes quickly through
the decomposition lock-so quickly that the
| air is not held in solution in the blood, but
escapes in bubbles in the tissues-this free
air causes II not death, train Of severe
| and dangerous symptoms. Physicians have
been somewhat slow in accepting the ex-
PLANTATION of bends probably because the
| facts seem more tangible to a physicist than
| to one trained to medicine, and also be-
cause the observation of cases in the, hos
| pital has revealed little in explanation of
| the disease and nothing as to means Of
| treatment. In fact, bends Is a condition
which need almost never occur.
Leonard Hill and Macleod, two physiolo-
gists of the London Hospital, have repeat
| eddy placed monkeys in a small caisson and
| subjected them to a pressure Of eight at
mospheres, G17.6 pounds per square inch)
| without any apparent injury to the animals
| These investigators, however, allowed two
| hours for decomposition from this high
| pressure, which is much more than Is ordi-
| narily used in any engineering construction.
1t is the belief at present that at least fif-
| teen minutes for each atmosphere Of pres
sure should be taken in order to be within
| the bounds of safety. but whether this pre-
| caution will ever be rigidly observed Is
questionable, and 1t would be safe to say
| that the men themselves, as much as any
| construction company. would object to a
period of half hour spent in decompres-
| sion lock, when there is a possibility that
no harm would come If only five minutes
were allowed for the operation"