STABSARZT PROF. DR. E. HOLZLOEHNER
STABSARZT DR. S. RASCHER
STABSARZT DR. E. FINKE
_I. Problem of the Experiment_
Up to the present time there has been no basis for the treatment of
shipwrecked persons who have been exposed for long periods of time to
low-water temperatures. These uncertainties extended to the possible
physical and pharmacological methods of attack. It was not clear, for
example, whether those who had been rescued should be warmed quickly or
slowly. According to the current instructions for treating frozen
people, a slow warming up seemed to be indicated. Certain theoretical
considerations could be adduced for a slow warming. Well-founded
suggestions were missing for a promising medicinal therapy.
All these uncertainties rested in the last analysis upon the absence of
well-founded concepts concerning the cause of death by cold in human
beings. In the meantime, in order to clarify this question, a series of
animal experiments were started. And, indeed, these officials who wished
to make definite suggestions to the doctors in the sea-rescue service
had to assume a great deal of responsibility if it came to a question of
convincing and consistent results in these animal experiments. At this
particular point it is especially difficult to carry the findings in
animals over into the human field. In the warm-blooded, one finds a
varied degree of development in the heat-regulating mechanism. Besides
this, the processes in the skin of the pelted animals cannot be carried
over to man.
_II. General Procedure of the Experiment_
The effect of _water temperatures_ of 2°, 3°, to 12° C. [34°, 37°, to
54° F.] were investigated. A tank 2×2×2 m. [6-2/3×6-2/3×6-2/3 ft.]
served as an _experimental basin_. The water temperature was attained by
addition of ice, and remained constant during the experiment. The
experimental subjects were generally dressed in _equipment_ such as the
flier wears, consisting of underclothing, uniform, a one piece summer or
winter protective suit, helmet, and aviators fur-lined boots. In
addition they wore a life preserver of rubber or kapok. The effect of
_additional protective clothing_ against water-cold was tested in a
special series of experiments, and in another series the _cooling of the
unclothed person_ was studied.
The _bodily warmth_ was measured _thermoelectrically_. Following
preliminary experiments in which gastric temperatures were measured by a
thermic sound, we adopted the procedure of continuously registering
_rectally_ the body temperature [Kerntemperatur]. Parallel with this,
the recording of the _skin temperature_ was undertaken. The point of
measurement was the skin of the back at the level of the fifth thoracic
certebral process. The thermoelectrical measurements were controlled
before, during, and after the experiments by thermometric tests of the
cheek and rectal temperature.
In severe cooling, _checking of the pulse_ is difficult. The pulse
becomes weaker, the musculature become stiff, and shivering sets in.
Auscultation during the experiment by means of a tube stethoscope
fastened over the tip of the heart proved effective. The tubes were led
out of the uniform and made possible the continuous _listening to the
heart during the stay in the water_.
_Electrocardiographic controls_ were not possible in the water. After
removal from the water they were possible only in those cases in which,
a too severe muscle shivering did not disturb the electrocardiograph
records.
The following _chemical studies_ were carried out: following up of the
_blood sugar picture_ (continuous); the _sodium chloride picture_ in the
serum; the _nonprotein nitrogen_ (_Rest-N_); the _alkali reserve_; the
alkali reserve of the venous and arterial blood and _sedimentation rate_
(before and after the experiment). Besides this the general _blood
condition_ and _viscosity_ were followed during the experiment, and
before and after the experiment the _resistance_ of the red blood cells
and the protein content of the blood plasma (this refractometrically)
were measured.
The following _urinalyses_ were made regularly: _sediment_, _albumen_,
_sugar_, _sodium chloride_, _acetone_, _acetic acid_, as well as a
qualitative _albumen_ determination.
In part of the experiment lumbar and suboccipital punctures were made as
well as corresponding spinal fluid studies.
Among _physical_ and _therapeutic measures_ the following were tested:
_a._ Rapid warming by means of a _hot_ bath.
_b._ Warming by means of a _light cradle_.
_c._ Warming in a heated _sleeping bag_.
_d._ Vigorous _massage_ of the whole body.
_e._ _Wrapping in covers._
_f._ _Diathermy of the heart._
In addition the following drugs were given: _Strophanthin_ i. v.;
_Cardiaz_ 1 i. v. and i. c.; _Lobelin and Coramin_ i. v. and i. c. In
other experiments alcohol or grape sugar was given.
A part of the experiments was begun under _narcosis_ (8 cc. _Evipan_ i.
v.).
_III. The Clinical Picture of Cooling_
The clinical picture as well as the behavior of the body temperature
showed certain regularities in the general course; the time of
appearance of certain phenomena was, however, subject to very great
_individual variations_. As one might expect, a _good general physical
condition_ delayed the cooling and the concomitant phenomena. Further
differences were conditioned by the _position of the subject in the
water_ and the _manner of clothing_. Furthermore, differences showed up
between experiments in which the subject lay horizontally in the water
so that the nape of the neck and the back of the head were splashed with
water, and others in which neck and head protruded freely out of the
water.
Peculiarly, the _actual water temperatures_ between 2° C. and 12° C.
[35° and 54° F.] had no demonstrable effect upon the rate of the
cooling. Naturally such an effect must exist. But since besides the
already mentioned individual differences and those due to experimental
conditions, the various subjects cooled on different days at different
rates of speed, the effect of the actual water temperatures between 2°
and 12° disappears behind such variations.
If the experimental subject was placed in the water under narcosis, one
observed a certain arousing effect. The subject began to groan and made
some defensive movements. In a few cases a state of excitation
developed. This was especially severe in the cooling of head and neck.
But never was a complete cessation of the narcosis observed. The
defensive movements ceased after about 5 minutes. There followed a
progressive rigor, which developed especially strongly in the arm
musculature; the arms were strongly flexed and pressed to the body. The
rigor increased with the continuation of the cooling, now and then
interrupted by tonic-clonic twitchings. With still more marked sinking
of the body temperature it suddenly ceased. These cases ended fatally,
without any successful results from resuscitation efforts.
In the course of the narcosis experiments the evipan effects in a few
cases went directly over into a cold narcosis; in other cases one could
determine a transitory return of consciousness, immediately following
the awakening effect already described; at any rate, the experimental
subjects were dizzy. Cold pain was not expressed.
Experiments without narcosis showed no essential differences in the
course of cooling. Upon entry into the water a severe cold shuddering
appeared. The cooling of the neck and back of the head was felt as
especially painful, but already after 5 to 10 minutes a significant
weakening of the pain sensation was observable. Rigor developed after
this time in the same manner as under narcosis, likewise the
tonic-clonic twitchings. At this point speech became difficult because
the rigor also affected the speech musculature.
Simultaneously with the rigor a severe _difficulty in breathing_ set in
with or without narcosis. It was reported that, so to speak, an iron
ring was placed about the chest. Objectively, already at the beginning
of this breathing difficulty, a marked _dilatation of the nostrils_
occurred. The _expiration was prolonged and visibly difficult_. This
difficulty passed over into a rattling and snoring breathing. However,
the breathing at this point was not especially deep as in Kussmaul’s
breathing nor were any Cheyne-Stokes breathing or Biot’s breathing to be
observed. Not in all subjects, but in a great number, a simultaneous
hindering during this breathing through very profuse _secretion of
mucous_ could be established. Under these conditions sometimes a white,
_fine-bubbled foam_ appeared at the mouth which reminded one of an
incipient _lung oedema_, though it was not possible to determine this
symptom with certainty by clinical auscultation; only a sharpened
unclean breath sound was audible. This foam might occur early, that is,
at rectal temperatures of 32° C. to 35° C.; [90°-95° F.]. No special
significance was to be attributed to this regarding the outcome of the
experiment which is the opposite of the described relaxation of rigor.
The _rate of breathing increased_ at the beginning of the experiment,
but after about 20 minutes it decreased to something like 24 per minute
with slight variations.
In general a definite _dulling of consciousness_ occurred at the
dropping of the body temperature of 31° C. [88° F.] rectal temperature.
Next, the subjects still responded to speech but finally answered very
sleepily. The _pupils_ dilated markedly. The contraction under light
became increasingly weaker. The gaze was directed overhead with a
compulsive fixation. After withdrawal from the water _an increase in the
reflexes_ was evident in spite of the rigor, and regularly a very marked
drawing up of the testicles occurred which practically disappeared into
the abdomen. Early in the experiment the _face_ was pale. After 40 to 50
minutes _cyanosis_ appeared. With this the face appeared redder, the
mucous membrane bluish-red. The skin veins were not maximally collapsed
and were virtually always penetrable.
The _heart activity_ showed a constant change independent of all other
individual variations, which was noticeable in all subjects. Upon
introduction into the water with narcotized subjects as well as
nonnarcotized subjects, the heart rate went suddenly to about 120 per
minute. At a rectal body temperature of about 34° C. [93° F.] it then
began to become increasingly slower and to sink continuously to about 50
per minute.
The bradycardia at a body temperature of about 29° to 30° C. [84° to 86°
F.] changed suddenly to an _arrythmia perpetua_ or, as the case may be,
to a _total irregularity_ and this began with a slow form of about 50
beats per minute; this slow form of irregularity could be transformed
into a faster one. The transformation to the faster form was not an
unfavorable sign regarding life.
When an electrocardiographic control after the experiment was possible,
it regularly showed a Vorhof flutter. Let it be anticipated _that this
irregularity could continue to exist after the cessation of the cooling
and a recovery of the body temperature to 33° or 34° C. [91° or 93° F.]
1½ to 2 hours after removal from the water_, but then customarily
changed of itself and without therapeutic aids into a coordinated heart
activity. In the same way let it be anticipated that in all cases with a
lethal termination, a sudden cessation of the heartbeat ensued upon an
irregularity of the slow type.
A check of the _blood pressure_ was attempted, but was in no case
satisfactory since an exact measurement was not possible in the decisive
stage of the experiment because of the severe rigor and muscle
fibrillation.
Reference has already been made to _individual differences in the
behavior of the rectal temperatures_. Figure 4 gives an example which
includes four experiments, in which four different experimental subjects
were cooled at identical water temperatures and with identical clothing.
It was shown that in water at 4.5° C. [40° F.] temperature the time
required for reaching a rectal temperature of about 29.5° C. [85° F.]
varies between 70 and 90 minutes. But nevertheless the diagram shows
that in spite of these individual differences, it is observable that the
progress of the rectal temperature proceeds according to rule. The body
temperature begins to sink rapidly from about 35° C. [95°-97° F.].
_It is of very great practical significance at this point that the body
temperature continues to sink virtually lineally for a considerable time
after removal from the water._ This continued drop can last 20 minutes
or more. During this drop an after-drop of 4° C. [7° F.] could be
observed, and indeed not only at temperatures under 30° C. [86° F.]. In
one case it was observed that an interruption of the experiment at 35°
C. [95° F.] after a further lapse of 20 minutes the rectal temperature
had fallen 4° to 5° C. [8° F.] more. We will later discuss the
“arresting” of this after-drop by physical measures.
In our experimental series, the lowest rectal temperatures which could
be survived varied individually just as did the progress of the
temperature drop. In general (in six cases) death occurred with a drop
in temperature to values between 24.2° and 25.7° C. [75.6° and 77.6°
F.]. In one case, however, a drop to 25.2° C. was survived. This
experiment fell outside the typical picture insofar as after 90 minutes
at 26.6° C. [79.9° F.] a virtually stationary condition of the rectal
temperature had become established for 85 minutes. We will come back
again to this special experiment.
The _skin temperature_ sinks or drops much more rapidly than the rectal
temperature. Within a minute there occurs a thorough saturation of the
articles of clothing. Correspondingly the skin temperature falls already
within 5 minutes to values between 24° and 19° C. [75° and 66° F.].
After 10 minutes it may have already dropped to 12° C. [54° F.]. Within
10 to 20 minutes more after the beginning of the experiment the
steepness of the drop changes considerably. The curve of the skin
temperature runs for some time, that is, for 15 to 30 minutes virtually
horizontal. After this time there follows a further but now slower drop
to the lowest figures, which may lie below 15° C. [59° F.] at the close
of the experiment.
Parallel experiments which compare the _course of the rectal
temperatures_ and the cooling of the body with and _without submersion
of neck and back of head_ showed great difference in temperature drop.
The curves pertain to the same experimental subject. The one with the
deep fall to 26° C. [79° F.] in 70 minutes was obtained with a water
temperature of 12° C. [54° F.] the other with a drop to 32.5° C. [90.4°
F.] in the same time resulted from a water temperature of 5.5° C. [41.9°
F.]. The very marked difference cannot be explained by a variation in
resistance of the particular person, but is to be attributed to the
position of the subject in the water and his head covering. In the
experiment with the water at 12° C. [54° F.] the subject, in a kapok
life preserver, lay flat in the water so that his neck and the back of
his head were well submerged; beyond this he did not wear a flier’s
helmet. In the other experiment with water at 5.5° C. [41.9° F.] the
head was covered with an aviator’s summer helmet without headphones. The
subject wore a rubber life preserver open at the back; with this, the
head is somewhat out of the water.
In order to follow up the effect of _isolated cooling of the neck and
the back of the head_ on consciousness, body temperature, and
circulation, this was undertaken in three special experiments. The
experimental subject lay horizontal; the back of the head and the neck
were dipped into a receptacle through which water of corresponding
temperature was continuously run. In an experiment of 3 hours duration
there occurred small temperature drops of not more than 0.8° C. [1.4°
F.]. The water temperature was 1° to 2° C. [34° to 35° F.]. In one case
after 50 minutes a marked sleepiness occurred which changed over into a
deep narcosis. The heart activity was variable, and obvious bradycardia
could not be observed. Irregularity never developed. Changes were not
seen in the electrocardiograph. On the other hand in all three subjects
the spinal fluid pressure was markedly increased after the ending of the
experiment to maximal values of 300 mm. After the experiment, ataxia and
definite Romberg phenomena were observed, as well as exaggeration of the
normal reflexes; pathological reflexes were absent.
_IV. Blood, Spinal Fluid, and Urine During Freezing_
The _differential blood smears_ showed no special features during
cooling. On the other hand the number of white and red blood corpuscles
shows a regular change. The _number of leukocytes_ rapidly increases,
roughly with the beginning of the steeper temperature drop at about 35°
C. [95° F.] rectal temperature to values of from 25,000 to 27,000 per
cu. mm. After one hour a maximum may be reached and a falling-off begins
in the number of leukocytes, while the body temperature falls still
further. The number of red corpuscles undergoes an increase, though to a
relatively small degree, which in its course resembles the change in the
_number of leukocytes_. We saw increases up to 20 percent. This increase
is interrupted even earlier than the increase in the number of
leukocytes, so that both curves give no reflection of the temperature
curve. The increase of the erythrocytes corresponded to the increase of
the hemoglobin of from 10 to 20 percent. A reduction of the fragility of
the red corpuscles could not be demonstrated with certainty, on the
other hand, although in three experiments a definite hemolysis occurred.
The viscosity regularly increases with the beginning of the fall in
temperature. The rise can reach values up to 7.8. This rise occurs very
early, indeed, already at body temperatures of 35° C. [95° F.]. After
that the values remain relatively constant with further temperature
falls. The _albumen content of the plasma_ was likewise increased after
the experiment, on the average by 1 percent of the absolute value. Since
these measurements could not be made as often as those of viscosity for
technical reasons, the connection with the progress of the viscosity
remained unclear. Such a connection could not be recognized from the
absolute values obtained.
With the acceleration of the temperature drop, there always occurs a
more marked increase of the blood sugar to maximal values which may
attain an average _increase of 80 percent_ and in a few cases may reach
an _increase of over 100 percent_. According to that, the maximal value
of about 27.5° C. [81.5° F.] is reached and is maintained for some time.
It is to be observed that _as long as the temperature drop continues, in
no experiment was it possible to observe a decrease in these high blood
sugar values_. It is usually to be observed that a relatively rapid drop
of the blood sugar values sets in when, after removal from the water,
the temperature drop ceases and goes over into a temperature rise. We
consider these findings to be of theoretical significance. During the
isolated cooling of the neck and back of the head which was described in
section III the blood sugar remained constant.
In striking contrast to the increase of the blood sugar, there was never
established a _corresponding glycosuria_ in the urine collected
immediately after the experiment or withdrawn through a catheter,
although considerable quantities of urine averaging 500 cc. were found
in the bladder; in only two cases could traces of sugar (0.5 percent) be
demonstrated. This paradoxical behavior can, perhaps, be explained in
this manner: during the time of great blood sugar increase, a blocking
of the kidneys had occurred, and that the associated urine quantities
were formed before or after this blocking under reflex polyuria. Acetone
and acetic acid, likewise, could not be demonstrated in the urine.
The _alkali reserve_ in the arterial and venous blood was regularly very
much reduced at the end of the experiments. Experiments concerning
_oxygen saturation_ could not be carried out. According to the color of
the venous blood withdrawn from the arm veins, the saturation of this
blood must have been very greatly reduced; the blood was virtually black
as it came into the syringe. Noteworthy in this connection are the
autopsy findings which were undertaken directly after death. In these,
the blood in the right heart appeared very dark, and in the left heart
very bright red. According to this, one must calculate upon an _increase
in the saturation differential between the arteries and veins_.
_Sodium chloride_ and _nonprotein nitrogen_ in the blood were not clear
in the blood at the end of the experiments or increased within the limit
of error. _Sodium chloride in the urine_ was generally less,
corresponding to a reduction of the specific gravity. On the other hand
at the end of the experiments _traces of albumin_ could regularly be
demonstrated _in the urine_ and moderately increased leukocytes,
occasional erythrocytes, and epithelial cells in the sediments. In
particular cases, _albumin casts_ were also observed. The reaction of
the urine remained identical before and after the experiments virtually
without exception. The studies of the bile yielded no results.
_Lumbar and suboccipital_ punctures immediately after the experiments
showed a considerable _increase in fluid pressure_. On the average it
amounted to between 50 and 60 mm. In one case, an _increase to 420 mm._
was seen. The protein values were always normal. Cell increases did not
appear, likewise no abnormal deviation of the colloidal gold curve was
observed. The meaning of these findings for therapy is still to be
discussed later.
_V. Recovery After Cooling and Its Dependence Upon Physiotherapeutic
Measures_
The important fact has already been referred to that after rescue from
the cold water, the body temperature sinks further and so a further
temperature reduction of 4° C. [7° F.] may take place. As was likewise
emphasized, this may occur as a postphenomenon not only when low
temperatures have been obtained already during the experiments, but it
can be noted also at final temperatures of 35° C. [95° F.]. A dependence
of this after-drop on the duration of the experiment could not be
established; as a result it is difficult to calculate in advance. This
fact becomes of great importance for practical measures; on the other
hand it makes it difficult to gain an insight into the manner in which
various physiotherapeutic measures affect the arresting of this
after-drop and the recovery of the body temperature. Only because of the
large number of the experiments was it possible to obtain well-founded
concepts of this.
The _flattest rise of the body temperature_ was to be observed when the
subject was merely dried off, wrapped in warm cover, and left to himself
after removal from the water. The recovery is greatly accelerated if the
subject is placed in a hot bath as soon as possible after the removal of
the wet articles of clothing. Warming under a light cradle assisted the
temperature rise. Vigorous massage had a favorable effect, however, only
if it was preceded by treatment in a hot bath or light cradle. _In no
case was it established that there was any indication of bad effects
from the hot water or the light cradle, or that the subject had been
harmed in any way._ On the other hand, it was observed in three cases
that a hot bath had doubtless a life saving effect. In two of these
cases there had been complete cessation of heart and breathing action,
and in one case the heart had stopped for several seconds after a
markedly slackened irregularity before the subject was placed into water
of not more than 50° C. [122° F.]. _As a result of this we can discard
all traditional objections to a sudden rewarming._
The favorable effect of a hot bath is still clearer in the observation
of the general condition of the subject than in the temperature curves,
although it cannot be presented objectively. The breathing very often
becomes “freer” immediately upon introduction into the hot water. The
hot water releases a strong stimulus; the unconscious subject often
reacts with an outcry. Soon thereafter there occurs a distinct lessening
of the severe rigor. The return of consciousness occurs sooner, and
indeed at temperatures at which it did not usually happen under other
methods of treatment.
In the first experiments with hot water treatment, this was continued
only for 10 minutes; after that the subjects were removed and vigorously
massaged. Under these circumstances it could be established that the
temperature rise continued during the rubbing, indeed in one experiment
the rise became steeper. As already indicated, this favorable effect of
dry rubbing was not so pronounced without preliminary treatment by heat.
It is important, too, that the rubbing be done when the severe spasm of
the peripheral vessels has already passed.
_In view of this, the hot hath is the best method of treatment of the
severely cooled person._ However, in the practice of sea rescue service
it will not be possible to carry out this method, since the necessary
means are not available in aircraft and boats. Under these circumstances
we must consider next only the rapid rewarming with light cradle or
electrically _heated sleeping bag_. Therefore a sleeping bag as now used
in the sea rescue service was also tested. It was evident that the
temperatures which can be developed by this means are not sufficient for
heat therapy. With those it was possible to reach a temperature of only
32° C. [90° F.] over the skin, with the heat turned on fully. Besides
this, the wall of the foot-section of the sleeping bag is only partly
heated; on the outer sides it remains completely cold. As long as no
improvement and strengthening of the heating equipment of the sack is
carried out, the sleeping bag can be considered only as a substitute for
wrapping in warm covers.
The warming by means of the _light cradle_ is more uneven than with a
hot bath. With warming by light one might expect severe local vessel
expansion with _danger of collapse_. Actually the subjects often
complained of dizziness and nausea after reaching consciousness if the
treatment lasted longer than 15 minutes. Occasionally vomiting occurred.
In these cases it is indicated to switch off the light cradle and to
pack the subject with covers. Apart from this it must be remembered that
during unconsciousness the subject should be protected against direct
contact with the lamps by means of covers, otherwise burns could occur
during clonic-tonic convulsions.
This suggests that “_short waves_” be employed to supply heat, since it
was shown in animal experimentation that by this means it is possible to
bring about a thorough warming of the whole animal, which leads to a
recovery of the animal with puzzling rapidity. We did not have the
proper equipment for a thorough warming of a human being by this means.
For this reason the _short wave therapy of the heart_ was tried. This
did not have any demonstrable effect. Above all, it is necessary to
advise against a practical application of this method, since there
exists the danger of prolonged burning even in full consciousness, as
the result of cold anaesthesia, even if the treating physician carefully
tries to avoid this.
The severe difficulty in breathing as well as the formation of foam
before the mouth, which reminded one of incipient lung oedema, seemed to
indicate oxygen therapy. Therefore this therapy was tried in four
experiments. It showed no effect on either the breathing or the heart
action. It has been pointed out that the arterial blood appears
especially light red.
_VI. Death After Cooling in Water_
_Practical and Theoretical Considerations_
Reports to the effect that those who have been rescued at sea are
imperilled for a considerable time after rescue has aroused special
attention. It has been reported especially that sudden cases of death
occurred as much as 20 minutes to 90 minutes after rescue, and that in
mass catastrophes these sudden deaths could amount to mass-dying (rescue
collapse). These observations have set off far-reaching discussions.
Bleeding in the rewarming periphery, break-downs of neural and humoral
correlations and similar ideas have been brought up.
In contrast to this our experiments give a relatively simple explanation
of cold-death under these conditions. With the exception of a single
case, a total irregularity of the heart chamber could be definitely
demonstrated in all cases of cooling under 30° C. [86° F.], (50
experiments), when the rectal temperature reached 29° C. [84° F.] and
usually already at a cooling of 31° C. [88° F.]. The exception was an
experiment on an intoxicated subject, which is to be gone into more
fully below (_see sec. VII_).
_Furthermore heart-death was established clinically in all cases of
death observed by us._ In two cases breathing ceased simultaneously with
the heart activity. These were cases in which it was specially noted
that the neck and the back of the head lay deep in the water. In all
remaining cases breathing outlasted the clinical chamber cessation by as
much as 20 minutes. In part this was “normal, much decelerated
breathing,” in part an angonal form of gasping. As already referred to,
an auricular flutter could be demonstrated cardiographically during the
irregularity.
In cases in which a special _cooling of neck and back of head_ had
existed before death, the _autopsy_ showed _a marked brain oedema_, a
tight filling of the general brain cavity [Hirngefaesse] blood in the
spinal fluid as well as blood in the Michaelisrhomboid.
The heart findings warrant our taking a certain attitude toward _the
question of rescue collapse_. Death occurred relatively quickly after
removal from the water, which may be compared with rescue. The longest
interval involved was 14 minutes. It is to be noted, however, in the
first place, that almost certainly a much larger number of deaths would
have been observed if an active heat therapy had not almost regularly
been coupled directly with the completion of the experiment; in the
second place, that in such cases there would have been very much longer
intervals. We have already called attention repeatedly to the
after-cooling following the experiment. In every case where this had
proceeded to a certain point, countermeasures were taken, since the
experiments were never planned to end in death. One may well imagine,
however, that in mass catastrophes, in which almost exclusively rescue
collapse has heretofore been described, the therapeutic measures were
confined to an undressing and drying off of the rescued together with a
subsequent wrapping in covers. Under these conditions after-drops of
great magnitude and long duration were to be expected. In the course of
this delayed fall in temperature, a heart-death might occur as in our
experiments.
_We should like to emphasize that the irregularity per se is not to be
regarded in our experiments as a symptom of danger to life any more than
in the clinic, but rather as a sign of direct heart damage, which
increases continuously with further falling off of temperature, until
finally the heart fails. If the temperature drop is arrested, the slow
form of irregularity passes over into a rapid form._ This transition is
a favorable sign for survival; for this irregularity virtually always
passes over of itself after a time averaging 90 minutes into normal
heart activity. It continues therefore for a long time after the body
temperature has already risen markedly. A danger to the circulatory
system could not be demonstrated at this stage. In three cases the
return of the heart action to normal occurred in spite of simultaneous
energetic physical work.
With the demonstration that cold-death of man is primarily a
heart-death, the essential points for therapy are also cleared up. The
_cause of the severe heart_ damage is another question. Since our
studies were primarily aimed at the development of practical methods of
treatment, we will not go very far into the theoretical concepts which
may be developed in this connection. Still, several hints may be drawn
from the blood studies:
1. The great increase of the _viscosity_ causes an _increased loading_
upon the heart.
2. The _choking of peripheral vessel_ areas by the severe vessel
contraction leads to an over-filling of the central areas. This appears
not only from our autopsies. In all available records of autopsies which
pertain to cases of death from cold in the water after sea disaster, we
find uniformly a severe over-filling of the right heart.
3. It is to be calculated that, under the effect of the low blood
temperature, the _heart_ itself becomes severely _hypodynamic_. It has
been proved long ago in animal experimentation that a Vorhof flutter can
be developed by the overloading and cooling of the isolated heart.
Besides a physical damaging of the heart musculature by the cold, we
must also keep in mind the _damaging by pathological products of
metabolism_. Next, the sharp increase in blood sugar may be connected
with the increased outpouring of adrenalin. The constancy of this
increase of blood sugar during the temperature drop is, however,
remarkable. One may well assume that this flow of adrenalin exhausts
itself with the continuance of the temperature drop. With this there
would have to be a rapid decrease in the blood sugar if the oxidation
processes were to continue undisturbed. The decrease in the alkali
reserve or the development of an acidosis argues strongly for an injury.
Animal experiments, with general cooling, give grounds for believing
that the intermediary metabolism is disturbed during drops in
temperature; but this change is also discussed in connection with local
freezing of the human being and has been proved to a certain extent.
Furthermore, not only this disturbance shows a transition between
general and local damage by cold. In both cases there occurs an increase
in viscosity, which points to a change in the capillary walls and
indicates the conclusion that there is a change in the permeability of
those walls for protein and water.
The heart-death remains prominent, the regular increase of spinal fluid
pressure with severe cooling of the neck and back of the head leaves it
unsettled whether, in addition, this has pathognomonic significance for
the outcome. With a fluid pressure of 420 mm. it must in fact be assumed
that this participates in the development of bradycardia.
The detection of an increase in fluid pressure is also not without
significance for therapy. One may think of a lumbar or suboccipital
puncture as a measure to be prescribed. After a lumbar puncture there
occurs a transformation of the slow form of arrhythmia into the rapid
form. It must remain undecided whether such measures, which delay a
rapid, active rewarming, are to be recommended for practical application
in the sea-rescue service.
The idea that cold-death in water depends upon failure of the heart,
accompanied or unaccompanied by breathing, is subject to limitation. One
experiment among fifty-seven was typical. This involved survival of a
cooling to 25.2° C. [77.4° F.] during a stay of 3 hours in water of 5.5°
C. [41.4° F.]. The rectal temperature under these conditions remained
constant within slight variations between 27° and 25° C. [81° and 77°
F.] for the last hour and a half. Likewise, quite irregularly, no
increase in blood sugar occurred. But most striking was the fact that
until the end of the experiment and after its termination consciousness
was undisturbed. The course of the experiment reminded one of the
behavior of certain experimental animals which can withstand extremely
low body temperatures for long periods of time. Lower, warm-blooded
animals (for example, rats) can endure rectal temperatures of 20° C.
[68° F.] for several hours. It is conceivable that this atypical
experiment, had it been continued, would have shown also an atypical
cause of death. Against this we have the fact that an irregularity had
already set in but not before a temperature of 30.1° C. [86.2° F.] had
been reached.
Also, aside from the fluid pressure increase, the part which the
_central nervous system_ plays in the outcome of the experiment seems to
us to be _secondary_. The experiments with simultaneous cooling of the
neck of course showed how the cooling of the neck and back of the head
speeds up the lowering of temperature. This is to be explained by the
fact that the counter-controls which are relayed from the temperature
center to the periphery, either cannot exist further because of
hypofunction of the centers (effect of oedema and cooling), or are no
longer transmitted because of cold-blocking of the pathways. But
likewise central counter-controls for the areas of the peripheral
capillaries may fall; thus delaying the overloading of the heart by
extended periphera vasco friction.
_VII. The Influence of Pharmacology and the Question of Alcohol_
Now experiments by _Jarisch_ have shown that heart drugs like
_strophanthin_ and stimulants like _cardiazol_ and _coramine_ in
therapeutic doses may react _toxically_ upon cooled animals. These
findings are a warning to be most careful in the medicinal treatment of
severely cooled persons, though strophanthin and cardiazol have
heretofore been expressly recommended in such cases.
In experiments with fatal outcome, the stopping of the heart occurred
either in the water or after an interval of not more than 14 minutes
after removal from the water. With such a rapid course of events it is
unlikely that one can favorably influence the heart action by
intravenous injections of strophanthin, especially because the
circulation is at a very low ebb before the heart-death. For this
reason, in a case whose condition was already very dangerous,
_strophanthin was given intracardially_ in a dose of 0.25 mg. Thereupon
the heart condition grew still worse and after 5 minutes the heart
stopped. One had the impression that the heart action was made worse by
the intracardial injection of strophanthin. This is, however, the only
case which left the possibility of damage by strophanthin in doubt. No
such damage could ever be established in the intravenous injection of
strophanthin. On the other hand no therapeutic effect, even with maximal
doses of 0.5 mg., could be detected. Figure 11 [not reproduced], last
section, shows the total duration in 10 cases of the irregularity
observed without strophanthin dosage. This varies between 25 and 200
minutes. On the other hand in Figure 13 in the last section, first five
cross-rows there are corresponding time values of 175 to 360 minutes. At
various experimental time points during these experiments 0.25 to 0.5 of
strophanthin were given. Accordingly, a shortening of the duration of
the irregularity cannot be established. Furthermore no improvement of
the pulse or general condition was ever noted. Obviously these
experiments are too few to rule out a possible favorable effect in all
cases. Several hundred experiments would be necessary to obtain
statistically reliable data on this point. And so, since contrary to
animal experimentation, we could not unquestionably establish damage
following intravenous strophanthin dosage, we may leave it to the
treating physician whether or not he may still want to make an
_experiment with strophanthin_. To be sure, such an employment of it
must be advised against in case of a very much decelerated form of
irregularity. This will be observed when there is the greatest danger;
under such circumstances time should never be lost by experimenting with
drugs, but every effort should be made in the direction of intensive
heat therapy.
Also in the experiments with _cardiazol_, _coramin_ and _lobeline_ we
restricted ourselves primarily to determining whether injurious effects
occurred in the case of relatively large doses. Four cc. of 10 percent
coramin as well as 2 cc. of 1 percent lobeline were injected
intravenously at various stages of recovery without any marked objective
and subjective deterioration of the state of the heart, the breathing,
and the general condition. But just as with strophanthin, it is
impossible to rule out a possible therapeutically favorable effect
because of the small number of experiments. We never observed such an
effect. Especially the marked deepening of breathing and of the
irritability of the trigeminal nerve which usually sets in very suddenly
after coramin (for example, sneezing immediately after the injection)
were always missing. Contrary to strophanthin, in the case of which we
cannot advise against experimentation by intravenous injection under
certain conditions, we believe on theoretical grounds that such
experiments with _peripheral circulatory drugs_ which may heighten the
vessel tonus are not indicated because of the following considerations:
The damage to the heart is to be attributed, among other things, to an
overloading, which is caused by a blocking of enlarged vessel areas,
aside from an increase in viscosity. If the vessel tonus is further
increased in the areas which have remained unimpeded, the conditions for
the heart are thereby made worse.
The sceptical attitude toward the effect of drugs is strengthened above
all by the observation that in the majority of the experiments in which
no drugs were given, even the most severe disturbances of the peripheral
circulation were reduced remarkably rapidly under intensive heat
treatment. In this connection it must be emphasized that besides the
recovery of body temperature through heat therapy an unloading of the
heart takes place because the blocked areas open up. Contrary to earlier
concepts, according to which there was danger of hemorrhage into the
periphery during rapid rewarming, and according to which one sought to
avoid this hemorrhage by wrapping up the extremities as well as by very
slow warming, the “venalous bleeding into the periphery” may be
life-saving under some circumstances. An exception, namely, loval
pyperacmia after considerable rise in temperature and corresponding
reestablishment of circulation has already been described in the
reference to the danger in some cases of very prolonged treatment in the
light cradle.
The familiar increase of peripheral blood volume as a result of alcohol
leads one to expect that very intoxicated persons cool more rapidly.
Figure 14[28] shows an experiment from which we may conclude that
_actually acceleration of the cooling_ does set in after partaking
_liberally of alcohol before the experiment_. It is very remarkable that
in such an experiment, _the only exception among all cooling
experiments_, irregularity was absent in a cooling to 28.1° C. [82.6°
F.]. Even if it was not possible to reproduce this apparent protection
against irregularity caused by partaking of alcohol in control
experiments on other subjects, there remains the possibility that the
distending of the peripheral vessels delays the overloading of the
heart, just as on the other hand it increases the speed of cooling.
Our observations contradict the old seafaring custom of pouring
_alcohol_ into a person _already cooled_, since, according to these
observations the temperature tends, even in slight degrees of cooling,
to sink further for a long time after rescue. As long as there is no
active supply of heat from outside, the disadvantage of an increased
heat loss will reduce the utility of stopping the peripheral vessel
blockage. Also in _later stages_ of recovery one must obviously be very
careful in giving alcohol; above all, this warning is emphasized by the
possibility that one must reckon with a total irregularity after more
than an hour, which may go unnoticed by the inexperienced experimenter.
* * * * *
_VIII. Preventive Measures_
* * * * *
_IX. Concerning Life Jackets_ [_Schwimmwesten_]
* * * * *
_X. Summary_
1. The curve of rectal temperature of human beings chilled in water of
2° C. [35.6° F.] to 12° C. [53.6° F.] shows a gradual drop to about 35°
C. [95° F.], after which the drop becomes rapid. Death may occur at
rectal temperatures below 30° C. [86° F.].
2. Death results from heart failure. The direct damage to the heart
becomes evident from the total irregularity observed in all cases,
setting in at approximately 30° C. [86° F.]. This cardiac damage is due
to overloading of the heart, caused by the marked and regular increase
in the viscosity of the blood, as well as by the marked throttling of
large peripheral vascular areas; besides, a direct injury to the heart
by the cold is also probable.
3. If the neck is also chilled, the lowering of the temperature is more
rapid. This is due to interference with the temperature-regulating and
vascular centers; cerebral oedema also makes its appearance.
4. The blood sugar rises as the temperature falls, and the blood sugar
does not drop again as long as the body temperature continues to fall.
This fact suggests an intermediary disturbance of metabolism.
5. Respiration of the chilled subject is rendered difficult due to the
rigor of the respiratory musculature.
6. After removal from the cold water, the body temperature may continue
to fall for 15 minutes or longer. This may be an explanation of deaths
which occur after successful rescue from the sea.