Reprinted from The Journal of the American Medical Association
November 21, 1953, Vol. 153, pp. 1081-1085

Copyright, 1953, by American Medical Association

SURGERY BY DIRECT VISION IN THE OPEN
HEART DURING HYPOTHERMIA

Henry Swan, M.D., Irvin Zeavin, M.D.
S. Gilbert Blount Jr., M.D.

and

Robert W. Virtue, M.D., Ph.D., Denver

The heart for centuries was suspected of being a deli-
cate organ; the slightest injury was said to be uniformly
fatal. Both the great Billroth and Sir Stephen Paget de-
creed the organ to lie outside the domain of possible
surgery. Yet in reality the heart is a compact muscular
organ that, by virtue of highly specialized intrinsic prop-
erties, functions continuously throughout the lifetime of
the individual. It has an extraordinary capacity to adjust
to the changing needs of body circulation. Its inner com-
pulsion toward perpetual function is one of the most
critical aspects of the life drive of individuals and species.
Only when poisoned or deprived of its flow of nutrient re-
quirements will this persistent organ lie still or lose itself
in the quivering death of disorganized activity. A great
ability to withstand trauma and to adjust to the stresses
imposed by intrinsic disease emphasizes its essential
vitality. Given half a chance, the heart will beat.

Inthe period from 1895 to 1913, Di Vecchio, Haecker,
Schepelmann, Elsberg, and Carrel, as well as many
others, showed in the experimental laboratory that the
heart could withstand surgical trauma and that many
complex operative procedures could be performed with
relative safety. The main principles of cardiac surgery
were well demonstrated and established. The medical
tradition of centuries, however, could not be so easily set
aside—the heart was delicate and should not be touched!

 

This study was aided by a grant from the United States Public Health
Service.

From the departments of surgery and medicine, University of Colorado
School of Medicine.
2

Accordingly, for 25 years the treatment of acute trauma
was the only clinical application of this knowledge. In
1938, an event of great import occurred. Pediatrician
John Hubbard, of Boston, requested Robert Gross to
operate on a child suffering from a patent ductus arterio-
sus. The successful repair of this congenital “heart”
lesion provided the stimulus that has since resulted in
the general recognition that the heart is not unique among
the organs of the body: it is amenable to surgical therapy.

REVIEW OF SURGICAL PROCEDURES

For the past 15 years in the surgical laboratories and
clinics both in the United States and abroad, the princi-
ples underlying cardiac surgery have been reexplored
and the human application of these techniques has been
gradually expanded. In almost all instances, however,
these operations have been performed by closed meth-
ods; that is to say, the maneuvers within the heart have
been done blindly, guided only by the ‘“‘feel” of the pal-
pating finger. This type of procedure, while often effec-
tive, is at best a compromise. To obtain an unimpeded
view of the operative field is a fundamental principle of
surgery. Adequate exposure for direct vision is an essen-
tial component of every safe surgical procedure. In this
regard, the interior of the heart has offered some special
technical difficulties. Operations on the pericardium,
neighboring great vessels, or the exterior of the heart
chambers can be easily visualized. The necessity of
maintaining circulation during operative maneuvers in-
side the heart, however, has led investigators to seek the
solution of this interesting problem down two separate
avenues of study.

The first and more obvious method, of course, was to
provide a mechanical pump to furnish the driving force
for the biood and then to remove temporarily the heart
from the circulation. Either a single pump or two pumps
in association with an oxygenator (the animal’s own
lung, a homologous lung, or a mechanical device) could
be utilized, depending on whether one wished to open
one or both sides of the heart and depending on whether
defects existed in the cardiac septums. This approach to
3

the problem has been vigorously pursued in many labora-
tories, and recently a few clinical applications have been
made.

The technical difficulties associated with this method
are great. The instruments are costly and complex and
require many skilled persons to use them. A major opera-
tive procedure is required to attach the machine to, and
later remove it from, the patient’s circulatory system, nec-
essarily adding to the magnitude of the total operation
and to the postoperative morbidity. The blood of the
patient must be heparinized and its capacity to clot later
restored with protamine. Overloading of the circulation
must be avoided. Hemolysis and air embolism are haz-
ards. Blood flows from the coronary vein into the right
auricle and obscures the operative field unless special
suction techniques are applied to the sinus. Even so,
blood from the thebesian veins on the right and blood
from the bronchial artery, via the pulmonary veins, on
the left, appear to constitute inescapable flows. At its
very best, then, the pump-oxygenators have not yet pro-
duced a dry field in which to operate, although the de-
gree of blood flow may be compatible with intermittent
visual operative maneuvers. The solutions to many of
these problems associated with extracorporeal circula-
tions have been found; others will also be solved; but the
inherent characteristics of the technique seem unlikely
to change. These adverse characteristics are (1) its com-
plexity and expense, (2) the material increase in the mag-
nitude of operation, and (3) its failure to provide a dry
field for operation.

The other avenue of approach to the open heart has
been the attempt to lower the metabolism of the patient
until circulation can be interrupted for periods of time
long enough to allow deliberate and extensive intracar-
diac maneuvers. It must be remembered that interrup-
tion of circulation experimentally was early utilized by
Haecker, Schepelmann, and Carrel, and its limitations
were explored. In the normal animal, two to three min-
utes appeared to be the maximum allowable time before
cardiac or cerebral damage occurred. This technique has
4

recently been used clinically in a few instances,* but the
need for longer periods of exposure has sharply limited
the magnitude of the procedures that could be performed.

To Bigelow ? and Boerema * must go the credit for the
conception and demonstration that general hypothermia
can be employed to allow cessation of circulation for as
long as fifteen minutes in the dog. Since their initial re-
ports, study of the modality of cold has been made in
many laboratories. The risks appeared to be high when
cooling was associated with interrupted circulation and
the open heart. In Bigelow’s original series, only 15% of
the dogs survived. In the later studies of Lewis and
Taufic * and of Cookson and co-workers,® the mortality
was better but still high. The lethal complications were
primarily related to two phenomena: ventricular fibril-
lation and coronary air embolism. To make the use of
hypothermia safe for open cardiac procedures, these two
complications must be effectively prevented or managed.
Unfortunately, in one clinical trial made prior to the
series reported herewith, the mortality was high (about
73% ).° Much of this mortality was due to the desperate
nature of the lesions treated, but some was due to the
complications of hypothermia with arrest of circulation.
In another series, successful closure of interauricular
septal defect was achieved in three of six patients.’

1. Varco, R. L., in discussion on Muller, W. H., and Longmire,
W. P., Jr.: Surgical Treatment of Cardiac Valvular Stenosis, Surgery
20:42, 1951. Swan, H.; Forsee, J. H., and Goyette, E. M.: Foreign
Bodies in Heart, Ann. Surg. 185: 314, 1952.

2. Bigelow, W. G.; Callaghan, J. C., and Hopps, J. A.: General Hypo-
thermia for Experimental Intracardiac Surgery, Ann. Surg. 132: 531,
1950.

3. Boerema, I.; Wildschut, A.; Schmidt, W. J. H., and Broekhuysen, L.:
Experimental Researches into Hypothermia as Aid in Surgery of Heart,
Atch. chir. neerl. 8: 25, 1951.

4. Lewis, F. J., and Taufic, M.: Closure of Atrial Septal Defects with
Aid of Hypothermia: Experimental Accomplishments and Report of One
Successful Case, Surgery 33:52, 1953.

5. Cookson, B. A.; Neptune, W. B., and Bailey, C. P.: Hypothermia
as Means of Performing Intracardiac Surgery Under Direct Vision, Dis.
Chest. 22: 245, 1952.

6. Downing, D. F.; Cookson, B. A.; Keown, K., and Bailey, C. P.:
Hypothermia in Cardiac Surgery, exhibit at the American Medical Associ-
ation Meeting, New York, June, 1953.

7, Lewis, F. J.: Personal communication to the axthors,
EXPERIMENTAL STUDY

On the basis of extensive experimental evidence, to-
gether with clinical experience in 15 patients, we believe
that hypothermia in association with cessation of circu-
lation may now be performed with a degree of safety
that warrants a more extensive clinical trial. In our
standard experimental situation, a dog was anesthetized
with veterinary pentobarbital (Nembutal) and cooled in
ice water to a temperature of 20 to 25 C. Thoracotomy
was performed; flow of blood into the heart was oc-
cluded for 15 minutes, during which time a right auricu-
lar cardiotomy was performed. No other pharmaceutical
agents were employed. Artificial respiration was per-
formed by means of a mechanical respirator with oxygen
via an endotracheal tube. After operation the animal was
warmed in water at 45 C. A great variety of physiological
variables were studied with the hope of unearthing
changes that might be related to the incidence of ventricu-
lar fibrillation. This work has been reported elsewhere.*
In essence, however, two changes in body constants ap-
peared related to fibrillation.

The first change was in the concentration of carbon
dioxide in the blood (and probably the tissues). On the
basis of our work together with that of others,® it ap-
peared likely that a sudden fall in carbon dioxide from
an abnormally high level toward normal was a fibrillatory
stimulus in the dog. By means of hyperventilation to
control carbon dioxide accumulation (deliberate respira-
tory alkalosis) the incidence of ventricular fibrillation in
the experimental animal was reduced to a level of about
8%.

The second change was found to be a shift in the
locus of potassium. During cooling and hyperventilation
a fall in the potassium level in the serum was observed.
The exact significance of this change in terms of ventricu-

8. Swan, H.; Zeavin, I.; Holmes, J. H., and Montgomery, V.: Cessa-
tion of Circulation in General Hypothermia: I. Physiologic Changes and
Their Control, Ann. Surg. 188: 360, 1953.

9. Miller, F. A., and others: Respiratory Acidosis: Its Relationship to
Cardiac Function and other Physiological Mechanisms, Surgery 32: 171,
1952.
6

lar fibrillation was not understood, but the well-known
importance of this ion in relation to cardiac rhythm led
us to investigate the use of potassium as a defibrillatory
agent. Previously, in our hands, the use of electric shock
had been entirely ineffective as a means of resuscita-
tion of ventricular fibrillation in the hypothermic animal.
We now found, however, that by means of a potassium
chloride solution injected into the coronary circulation
we could routinely defibrillate the cold dog’s heart and
restore normal rhythm.

On the basis of these two phases of the study we felt
that ventricular fibrillation complicating hypothermia
could be largely prevented; even if it occurred, an effec-
tive means of resuscitation was available. The other chief
source of worry was related to the prevention of coronary
air embolism. Extremely small volumes of air entering
the coronary arteries are capable of causing myocardial
ischemia and death. If the cardiac septums are intact and
air enters the right side of the heart, a considerable vol-
ume may escape into the pulmonary circulation without
lethal effect. Air admitted directly into the left side of
the heart or indirectly via a right-to-left opening, such as
a septal defect or pulmonary arteriovenous fistula, con-
stitutes an immediate threat to life even if small amounts
should escape into the aorta. For this reason, great care
must be exercised to prevent this occurrence during open
cardiac operations. On the basis of experience with the
experimental creation of auricular septal defects, with the
use of an open approach through the right auricle in the
warm animal, a technique was developed to prevent this
catastrophe.'® Accordingly, in both our experimental and
our clinical experience using hypothermia, this compli-
cation did not occur.

Surgeons who have had the opportunity to watch
valvular function in the open beating heart are impressed
with the dual phase of the act of closure of the atrioven-
tricular valves. The first phase appears to be muscular

 

10. Swan, H.; Maresh, G.; Johnson, M. E., and Warner, G. W.: Experi-
mental Creation and Closure of Auricular Septal Defects, J. Thoracic
Surg. 20: 542, 1950.
7

and involves an actual narrowing of the ring at the base
of the valve. The second phase is hydrodynamic and re-
quires the presence of sufficient fluid within the ventricle
to swing the valve leaflets into the position of effective
closure. If the ventricle is filled with air, the second phase
does not occur, and the valve remains partially open.
Under these circumstances, the ventricle develops no
head of pressure to open the outflow valves and there is
no forward propulsion of either fluid or air; the aortic
and pulmonary valves remain closed.

The importance of these observations in terms of air
embolism to coronary arteries is obviously great. Air
embolism is unlikely to occur during the period when the
heart is open. The dangerous moment occurs immedi-
ately after closure of the myocardial incision and the
return of blood flow. Air trapped in the heart may now be
propelled forward into the peripheral or pulmonary cir-
culations. One of the prime means of prevention, there-
fore, is to remove all air from the heart before closure of
the myocardial incision.

The technique evolved may be described as follows.
Inflow of blood into the heart is stopped by occlusion
of the venae cavae. About one minute is allowed for the
beating heart to partially empty itself and the pulmonary
circuit. A noncrushing clamp is now placed across the
aorta and pulmonary arteries at their point of exit from
the ventricles. It is our intent that this clamp should actu-
ally occlude the orifices of the coronary arteries as an
added means of precaution. That it does so has been
demonstrated experimentally by dye injection techniques.
Movement of fluid through the exit valves of course
ceases at this moment. The heart is now opened, allowing
the residual blood to escape and air to enter. The opera-
tive procedure is performed within the allotted time limit.
Just before closure of the heart incision, the chest cavity
is rapidly flooded with Ringer’s solution until the entire
heart lies under water. As it beats, the air escapes through
the cardiac incision that lies uppermost as the Ringer’s
solution fills the chambers. After a few beats, it can be
clearly seen that no more air is bubbling up from the
heart. A second noncrushing clamp is then applied (un-
8

der water) to the cardiotomy incision, closing the heart.
The clamp across the aorta and pulmonary artery is
now removed. The superior vena cava is released and
blood flow allowed to resume. After about 30 to 60
seconds, when the heart seems to be tolerating its work
load again, the inferior vena cava is released and total
circulation is resumed. The cardiotomy may now be
closed with deliberation. It is important not merely to try
to fill the heart with Ringer’s solution but to completely
immerse the heart in the solution, just as one would sub-
merge a sponge in a bucket.

REPORT OF CASES

Case 1.—The patient was an 11-year-old cyanotic white boy
who weighed 74 lb. (33.6 kg.). The clinical diagnosis of isolated
pulmonic stenosis with patent foramen ovale was confirmed
by catheterization. On Jan. 9, 1953, hypothermia was induced
with the patient under thiopental (Pentothal)-cyclopropane-
ether anesthesia. After 37 minutes, when his body temperature
was 34 C, he was removed from the ice water. His lowest
temperature was 28 C. A standard transventricular pulmonary
valvulotomy was accomplished without circulatory occlusion.
All observers agreed that the heart was unusually stable
throughout the procedure. The patient had an uncomplicated
convalescence.

CasE 2.—A 12-year-old white girl, who weighed 60 Ib.
(27.2 kg.), had cyanotic congenital heart disease due to trans-
position of the great vessels with an interauricular septal defect.
A previous shunt operation had been done four years previ-
ously with improvement but had closed during the preceding
year. At operation on June 9, 1953, hypothermia was induced
with the patient under thiopental-cyclopropane-ether. After 35
minutes she was removed from the ice water, with a body
temperature of 31 C. Her lowest temperature was 26 C. An
intrapericardial anastomosis between the ascending aorta and
right pulmonary artery was accomplished without arrest of
circulation. The heart was very stable throughout. The patient
had an uneventful convalescence.

Casz 3.—The cyanotic congenital heart disease of an 8-year-
old white boy, who weighed 63 lb. (28.6 kg.) was confirmed
by catheterization to be isolated valvular pulmonic stenosis.
At operation on Feb. 19, 1953, hypothermia was induced with
the patient under thiopental-cyclopropane-ether anesthesia.
After 44 minutes he was removed frcm the ice water, with a
body temperature of 39 C. His lowest temperature was 25.2
C. Circulatory arrest was accomplished by complete cardiac
inflow occlusion for 7.5 minutes. Partial excision of the
9

stenosed pulmonic valve was accomplished under direct vision
through an incision in the pulmonary artery. Auricular fibril-
lation occurred during cooling but disappeared on rewarming
to 27 C. The patient had an uneventful convalescence.

Case 4.—The patient was a 7-year-old white boy who
weighed 51 lb. (23.1 kg.). Cyanotic congenital heart disease
was diagnosed as probable infundibular pulmonic stenosis
associated with tetralogy of Fallot. Hypothermia was induced
with the patient under thiopental-cyclopropane-ether anesthesia.
After 37 minutes he was removed from the ice water, with a
body temperature of 30 C. His lowest temperature was 23.6 C.
Circulatory arrest was accomplished by complete cardiac in-
flow tract occlusion for 2.1 minutes. The patient was found
to have pulmonic valvular stenosis as part of the tetralogy.
Half of the stenotic valve was excised under direct vision.
Auricular fibrillation occurred during cooling and disappeared
when the patient was rewarmed to 26.5 C. Convalescence was
uneventful.

Case 5.—The cyanotic congenital heart disease of an 8-year-
old white girl, who weighed 66 lb. (29.9 kg.), was established
by catheterization to be isolated valvular pulmonic stenosis.
At operation on March 10, 1953, hypothermia was induced
with the patient under thiopental-cyclopropane-ether anesthesia.
After 39 minutes she was removed from the ice water, with
a body temperature of 30 C. Her lowest temperature was 25.7
C. Circulatory arrest was accomplished by complete cardiac
inflow occlusion for 2.5 minutes. Pulmonic valvuloplasty by
incision in three places was performed under direct vision.
Auricular fibrillation occurred and disappeared when the
patient was rewarmed beyond 26 C. Convalescence was un-
eventful.

CasE 6.—The patient was a 9-year-old white boy who
weighed 66 Ib. (29.9 kg.). The clinical diagnosis of isolated
pure pulmonic stenosis was confirmed by catheterization. At
operation on April 14, 1953, hypothermia was induced with
the patient under thiopental-cyclopropane-ether. After 35
minutes he was removed from the ice water, with a body
temperature of 30.8 C. His lowest temperature was 23.7 C.
Circulatory arrest was accomplished by complete cardiac in-
flow tract occlusion for 2.5 minutes. Pulmonic valvuloplasty
by incision in three places was performed under direct vision.
Auricular fibrillation occurred and disappeared on rewarming
the patient beyond 26 C. Convalescence was uneventful.

CasE 7.—A 26-year-old white woman who weighed 104 Ib.
(47.2 kg.) had suffered progressive disability from a large
interatrial septal defect confirmed by catheterization on two
cccasions. At operation on April 15, 1953, hypothermia was
induced with the patient under thiopental-cyclopropane-ether
anesthesia. After 77 minutes she was removed from the ice
water, with a body temperature of 29 C. Her lowest tem-
10

perature was 22.3 C. Circulatory arrest was accomplished by
complete cardiac inflow occlusion for 7.5 minutes. The large
interatrial septal defect was closed with direct suture. Auricular
fibrillation occurred and disappeared when the patient was
rewarmed beyond 26.5 C. She was given a smaller transfusion
than would have been usual in such an operation because of
fear of heart failure. Shock occurring in the recovery room
was successfully combated with 1,500 cc. of blood. Con-
valescence was slow, with shifting arrhythmias that compli-
cated her course. Two months later the heart was smaller,
and a great increase in exercise tolerance had occurred.

CasE 8.—The cyanotic congenital heart disease of a 10-year-
old white boy, who weighed 70 1b. (31.8 kg.), was established
as tetralogy of Fallot by catheterization. At operation on April
21, 1953, hypothermia was induced with the patient under
cyclopropane-ether anesthesia. After 45 minutes he was re-
moved from the ice water, with a body temperature of 31 C.
His lowest temperature was 24.6 C. Circulatory arrest was
accomplished by complete cardiac inflow occlusion for 8.5
minutes. An infundibular stenosis was excised under direct
vision. An anomalous coronary artery frustrated attempt at a
larger ventriculotomy to repair the interventricular septal
defect. Cardiac arrest occurred during the operation but re-
sponded immediately to massage. Auricular fibrillation oc-
curred during cooling and disappeared on rewarming the
patient. Convalescence was uneventful.

Case 9.—A _ 6-year-old white girl, who weighed 41 Ib.
(18.6 kg.), had suffered progressive disability from a large
interatrial septal defect proved by catheterization. At opera-
tion on May 5, 1953, hypothermia was induced with the pa-
tient under thiopental-cyclopropane-ether anesthesia. After 40
minutes, she was removed from the ice water, with a body
temperature of 29 C. Ventricular fibrillation was noted four
minutes later, and cardiac massage was instituted rapidly.
Defibrillation was performed with 0.5 mEq. of potassium
chloride perfused into the coronary arteries. Her lowest
temperature was 22.6 C. Circulatory arrest was accomplished
by complete cardiac inflow occlusion for five minutes. A large
interatrial septal defect was closed by direct suture. Cardiac
arrest occurred after partial closure of the pericardium.
Massage and intracardiac injection of 2 cc. of 2% calcium
chloride were effective in restoring normal rhythm. Con-
valescence was uneventful except for temporary bilateral
peroneal palsy of unknown cause.

Case 10.—Isolated pulmonic valvular stenosis without
cyanosis was confirmed in a 3-year-old white girl, who
weighed 34 lb. (15.4 kg.), by catheterization. On June 12,
1953, hypothermia was induced with the patient under vinyl
ether (Vinethene) and ethyl ether anesthesia. After 23 minutes
she was taken from the ice water, with a body temperature
1]

of 30 C. Her lowest temperature was 25.5 C. Circulatory
arrest was accomplished by complete cardiac inflow occlusion
for 2.17 minutes. Incision of the thick stenosed pulmonic
valve was done in two places under direct vision, forming a
bicuspid valve. The patient had an uneventful convalescence.

Case 11.—The patient was a 4-year-old boy who weighed
only 26 Ib. (11.8 kg.). His interauricular septal defect with
tricuspid regurgitation had produced a very large heart border-
ing on failure, in spite of digitalis therapy during the past two
years. At operation on June 18, 1953, hypothermia was induced
with vinyl ether-ethyl ether anesthesia. After 19 minutes the
patient was removed from the ice water, with a body tem-
perature of 29 C. His lowest temperature was 21.5 C. Tech-
nical repair of the septal defect was accomplished satisfactorily
with seven minutes of inflow tract occlusion. The heart went
into standstill during occlusion and shortly afterward into
ventricular fibrillation. The patient was warmed to 33 C, while
cardiac massage maintained the circulation. The ventricles
were defibrillated with potassium. The beat, however, was
never vigorous, and the patient died with a dilated failing
myocardium.

Case 12.—The frail stature of a 6-year-old boy, who
weighed 40 Ib. (18.1 kg.), was due to a large interauricular
septal defect, although he had never been in frank heart
failure. At operation on June 26, 1953, hypothermia was in-
duced with the patient under thiopental-cyclopropane-ether
anesthesia. After 35 minutes he was removed from the ice
water, with a body temperature of 28 C. His lowest tempera-
ture was 25.5 C. A large interatrial septal defect was sutured
under direct vision during occlusion of circulation lasting 6
minutes 15 seconds. Auricular fibrillation reverted to sinus
rhythm on return of circulation. The patient’s postoperative
course was uneventful.

CasE 13.—The patient was a 3-month-old boy who was
suffering acute heart failure associated with intense cyanosis.
His condition improved with digitalis and oxygen, but three
days later jaundice developed, thought to be hepatic in origin.
On June 26, 1953, because of his large heart and his failure
to improve, he was operated on, with a diagnosis of possible
pulmonary valvular stenosis. Hypothermia was induced rapidly
’ with the patient under thiopental-ether anesthesia. After 11
minutes he was removed from the ice water, with a body
temperature of 30.8 C. His lowest temperature was 25.6 C.
Exploration revealed idiopathic pulmonary hypertension. No
therapeutic procedure was attempted. Immediate recovery was
satisfactory, but the patient subsequently died of his cardiac
malformation.

Case 14.—The cyanotic heart disease of a 28-year-old white
mother of 2 children had caused progressive disability for the
12

preceding two years. Two months before admission a right
hemiplegia had occurred. Clinical diagnosis of tetralogy of Fal-
lot was confirmed by angiocardiographic demonstration of in-
fundibular pulmonic stenosis. At operation on July 1, 1953,
cardiac standstill occurred after induction and intubation but
before cooling was. begun. Cardiac resuscitation was accom-
plished after 2 minutes 10 seconds by thoracotomy and mas-
sage. The wound was closed tightly with mattress sutures, and
the patient then cooled in ice water for 47 minutes to 31 C.
Her lowest temperature was 25.5 C. Cardiac arrest again
occurred as the chest was being prepared for draping. The
previous wound was rapidly reopened and the heart beat
restored by massage at 1 minute 10 seconds. From this point
on, the heart beat was remarkably stable. With circulatory
arrest lasting five minutes, a tight infundibular stenosis was
excised under direct vision through a right ventriculotomy. No
attempt was made to close a very small interventricular septal
defect. Immediately after the patient’s recovery from anesthesia,
cyanosis disappeared. The postoperative course was uneventful.

Case 15.—-The patient was a 20-month-old girl who weighed
18 lb. (8.2 kg.). Cyanosis during an upper respiratory infection
led to the diagnosis of pulmonic valvular stenosis with patent
foramen ovale. Operation was performed on July 9, 1953.
Hypothermia was induced with the patient under thiopental-
ether anesthesia. After 24 minutes she was removed from the
ice water, with a body temperature of 31 C. Her lowest tem-
perature was 27 C. Via an incision in the pulmonary artery,
plastic revision and partial excision of the stenotic pulmonary
valve was performed during circulatory arrest lasting 3 minutes
50 seconds. The patient’s operative course was uneventful,
and her immediate recovery was quite satisfactory.

COMMENT

These specific operations were chosen deliberately for
the initial experience with human hypothermia, because
the existing operations for the diseases treated have left
much to be desired. As experience has accumulated in
various clinics, it has become increasingly clear that the
transventricular incision and dilatation of the stenosed
pulmonary valve has given very disappointing objective
results.’' It is true the immediate clinical results are ex-

11. Bing, R.: Personal communication to the authors. Dodrill, F. D.;
Gerisch, R. A.; Johnson, A. S., and Hill, E.: Pulmonary Valvuloplasty
Under Direct Vision: Aid of Mechanical Right Heart, read before the
American Association of Thoracic Surgery, San Francisco, March, 1953.
Humphreys, G. H.; Powers, S. R.; Fitzpatrick, H. F., and Lanman, B. M.:
Pulmonary Valvular Stenosis: Clinical and Physiologic Studies of 25

Cases Treated by Valvulotomy, read before the Meeting of Society for
Vascular Surgery, New York, May, 1953.
13

celient. But surgeons who have studied, by actual meas-
urement, the residual right ventricular pressure weeks or
months following operation in these same patients have
found a disturbing number in whom this pressure is still
markedly elevated, that is, a systolic pressure of 70 mm.
Hg or more. This is a level approximately three times
normal, and, although it is lower than it was preopera-
tively, it is still pathologically elevated. One cannot
predict a normal life span for such a patient. It seems de-
sirable, therefore, to attempt a more complete plastic
revision of the valve, a maneuver easily made possible
by the direct vision technique.

Resection of infundibular stenosis blindly with ron-
geurs has not appealed to many surgeons. Resection of
a precise area under direct vision associated with the ad-
ditional possibility of closing the ventricular septal defect
in tetralogy of Fallot offers the potentiality of actually
curing the patient of his intracardiac defects. Clearly, if
the procedure is feasible and safe, this would be an ob-
jective superior to the addition of a shunt. Resection of
the stenosis is not unduly difficult, but closure of the
septal defect may prove more arduous.

The operations currently available for interauricular
septal defects are all blind manipulations and carry a sig-
nificant operative risk.’ Certain types of defects, particu-
larly septum primum lesions overlying the valves, are not
amenable to treatment by these methods. An open opera-
tive approach to this problem seems worthy of trial.

To date, we have used cooling with cessation of circu-
lation primarily in children, only two patients having
been adult. There is good experimental evidence that
the young tolerate this procedure with greater safety than
the older age group. We hope to establish the safety
of the procedure in this younger age group before pro-
ceeding to expand slowly into adult ranges.

 

12. Gross, R. E.; Watkins, E., Jr.; Pomeranz, A. A., and Goldsmith,
E. I.: Method for Surgical Closure of Interauricular Septal Defects,
Surg., Gynec. & Obst. 96:1, 1953. Swan, H.: Surgical Closure of Inter-
auricular Septal Defects, J. A. M. A. 151: 792 (March 7) 1953. Bailey,
Cc. P., and others: Congenital Interatrial Communications: Clinical and
Surgical Indications with Description of New Surgical Technique: Atrio-
Septo-Pexy, Ann. Int. Med. 37: 888, 1952.
14

We believe it is desirable to cool the patients as rapidly
as possible, perform the procedure, and then warm to
near normal temperatures at once. Cardiac irregularities
occur with great frequency in these sick hearts at levels
below 28 C. Auricular fibrillation, although common in
the human patient, is not a matter of great concern, be-
cause, in our experience, if it occurs during cooling, a
sinus rhythm will always return at approximately the
same temperature during rewarming. Ventricular fibril-
lation has occurred twice but was successfully reverted on
both occasions by the use of potassium. In one patient,
however, sustained spontaneous beat could not be subse-
quently obtained, we believe, because of cardiac dilata-
tion and myocardial failure. This was the only operative
death in the series.

The importance of an adequate exposure of the heart
and great vessels for this type of procedure must be em-
phasized. It is essential that all sides of the heart, the
superior and inferior venae cavae, the ascending aorta
and pulmonary artery, and the lung roots be readily
reached. For this, in our experience, there is no incision
equal to the bilateral transverse sternal-cutting inter-
costal incision in the fourth interspace. Although long,
the incision involves the removal of no part of the
thoracic skelton, is well tolerated by the patient, and
heals quickly, with minimal postoperative discomfort.”

SUMMARY AND CONCLUSIONS

Fifteen patients have undergone cardiac operations
while they were in a state of hypothermia, with body
temperatures ranging from 21.5 to 26 C. In 13 of these
patients, circulation was stopped for periods varying
from 2 to 812 minutes, and the operation was performed
in the open heart under direct vision. There was one
operative death in this group. The remainder of the pa-
tients have had excellent clinical results, save one on
whom no therapeutic procedure could be performed.

Hypothermia was induced during anesthesia by im-
mersing the patient in a tub full of ice water; warming
was also achieved in the tub with warm water. Speed of
cooling depended largely on body build; the less obese
15

patients cooled more rapidly. Prevention of shivering
and hyperventilation were very important aspects of the
cooling technique. Potassium appeared to be a valuable
agent for combating ventricular fibrillation in the cold
patient. The prevention of coronary artery air embolism
was of great importance and was achieved by a combina-
tion of maneuvers, of which one of the most important
was complete immersion of the heart in salt solution at
the time of closure of the cardiotomy.

Direct vision intracardiac surgery should be further
explored and possibly expanded in scope, since cessation
of circulation in the presence of hypothermia allows an
essentially bloodless field, with reasonable safety for
periods up to at least eight minutes. It is surprising how
much can be deliberately accomplished in this period of
time. Various forms of pulmonic stenosis in nine pa-
tients and interauricular septal defects in four have been
successfully repaired by this technique. Other stenotic or
regurgitant valve lesions and defects of the ventricular
septum may also prove to be amenable to therapy.

4200 E. 9th Ave. (7) (Dr. Swan).

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