PLASMA POTASSIUM CONTENT OF CARDIAC
BLOOD AT DEATH?

JOHN SCUDDER, MARGARET E. SMITH anp CHARLES R. DREW

From the Departments of Surgical Pathology and Surgery of Columbia University,
College of Physicians and Surgeons, and of the Presbyterian Hospital, New York City

Received for publication March 25, 1939

Potassium changes the properties of the surface layers of plant cells
when its concentration passes a certain point (Osterhout, 3). The effects
of lower concentration of potassium chloride on Nitella are perfectly
reversible even after several hours of contact. With 0.05 M potassium,
however, this reversibility ceases (Osterhout, 3).

The animal cell seems to be more sensitive to potassium as judged by
the effects of lower concentrations on the electrocardiograph tracings in
the dog (10), the cat (2), and the human (7). In the dog cardiac arrest
occurs at a concentration between 0.014 and 0.016 M. It has been sug-
gested that this is the critical concentration of potassium at which the heart
stops, the evidence being obtained from intravenous injections of potassium
salts into healthy dogs.

In pathological states caused by intestinal obstruction, intestinal fistulae,
hemorrhage, and various types of trauma (table 1), the concentration of
potassium in cardiac blood at the time of death varied between 0.0095
and 0.0114 M. in the cat (5, 6, 11, 12). In four dogs poisoned with potas-
sium this average concentration was a little higher, 0.0152 M (4).

Winkler, Hoff and Smith (10), on the basis of their work on dogs, in
which cardiac arrest was shown to be associated with a concentration of
potassium between 14-16 mM. per liter suggested that there is a wide
margin of safety for the human being, “since serum potassium would have
to be increased by some 9 mM. per liter to reach a fatal level.” ,

No such potassium concentration in the cardiac blood of humans has
been found in a series of cases studied during the past eighteen months.

MeEtHop. At the time of death, heart’s blood was withdrawn by cardiac
puncture into a sterile dry syringe. From 5 to 6 cc. of this sample were
introduced into a Sanford-Magath hematocrit tube containing heparin
(Connaught); gently mixed, capped, and centrifuged at 2,000 r.p.m. for
one hour. The plasma was removed immediately from the cells, and the

1 A study made possible by a grant from the Blood Transfusion Betterment Asso-
ciation, New York, New York.
337
338 J. SCUDDER, M. EB. SMITH AND C, R. DREW

potassium content of 0.5 ml was determined by a modification of the
argenticobaltinitrite method (8, 9), the final color being read on the Evelyn
Photoelectric Colorimeter with the appropriate filter.

With this method 17.2 mgm. per cent (0.0044 M) represents our normal
value derived from determinations done on sixty healthy voluntary
donors (table 2).

 

 

 

 

 

 

 

 

 

 

 

 

 

TABLE 1
Cardiac blood potassium
ake LESION RANGE AVERAGE avunacs avernacs M
Cats
mgm, per cent | ™4™. Dé mM. fl.
4 Intestinal obstruction 33.8-€6.6 44.5 11.4 0.0114
2 Intestinal fistula 40.6-45.5 43.1 11.0 0.0110
4 Hemorrhage 25.0-57 .4 46.5 11.9 0.0119
4 Trauma 30.6-41.0 37.2 9.5 0.0005
14 42.8 10.9 0.0109
Dogs
4 Poisoned with intravenous | 26.0-99.5 59.5 15.2 0.0152
isotonic KCl
TABLE 2
Plasma potassium of normal venous blood*
Sixty donors
Average (mean)...............0 000. c cece cece nent nee 17.2 mgm. per cent
Median. ........... 0... ccc cece nee cence eset e en entees 17.2 mgm. per cent
Range. .... 2.0.0... ccc cece cece ence eee ee een tans 13.5-21.5 mgm. per cent
Standard deviation...................00 cece cece eee ces 0.33 mgm
Coefficient of variation................ 00... c cece eee 1.9 per cent

 

* This group comprised 50 males and 10 females. Each value represents the mean
of two aliquots of the original sample, 0.5 ml. of plasma being used.

Discussion. Cardiac arrest appears to be associated with different
concentrations of potassium, not only for different species but also for
different individuals within the species. Plant cells seem to withstand
higher concentration of potassium than do animal cells.

The narrow range of potassium between 17.2 mgm. per cent (0.0044 M)
for normal circulating venous blood and 29.8 mgm. per cent (0.0076 M)
for cardiac blood plasma at death indicates possibly that human cardiac
PLASMA POTASSIUM OF CARDIAC BLOOD AT DEATH 339

muscle is more susceptible to variations in concentration than certain
plant and animal cells.

 

 

 

 

 

 

 

 

 

 

 

 

TABLE 3
Potassium content of cardiac blood at death
nos
wit « IN- PITAL PLAS-
BER _ DATE ITtALs AGE | SEX woM- DIAGNOSIS OPERATION wa K
BER
per
/ cont
1 | 8/90/37 |W.N. | 62 | M | 527186 | Multiple fractures and contu- | Debridement 38.5
- sions; laceration of aorta
2 | 9/93/37 | Vv. M. 9 | M | 580304 | Multiple fractures. | Hemo- | None 90.5 ~
: peritoneum
3 | 10/14/87 | N.L. | 28 | F | 880208 | Idiopathic gastro-intestinal Exploratory 2.0
4 | 11/98/37 | F.F. | 58 | M_ | 586668 | Perforated duodenal ulcer None 31.9
& | 3/24/88|D.P. | 25 | F | 542008 | Paraganglioma of adrenal cor- | Partialresection. | 34.1
tical tissue Operative death
6 | 6/8/38 }M.L. | 45 | F | 374560 | Chronic cholecystitis, chole- | Cholecystectomy, | 28.6*
Waawaeos bphrenio and | insisionand
subhepatic abscesses drainage ab-
scessea
7 | 9/18/88 |J.Mc. | 70 | M | 856217 | Carcinoma of colon with me- | Exploratory 26.3
tastases to liver
8 | 9/97/38 |)M.K. | 26 | F | 550662 | Intestinal obstruction compli- | Ileostomy 28.9
cating pregnancy
9 | 11/ 4/38 |L.wW. | 31 | F | 549087 | Mesenteric thrombosis Enterectomy 38.0
to | 11/ 7/38 | E.Mo.| 63 | F | 56918 | Acute pancreatitis None 31.6
11 | 13/18/38 |L.V. | 73 | F | 560067 | Diabetic gangrene Amputation 32.6
12 | 2/17/39 |L.H. | 88 | F | 566522 | Carcinoma of breast Mastectomy 36.1
13 | 2/26/39 | A.M. | 85.| M | 872868 | Pneumonia, type IIT 27.9
AVOTEZO,. 0c cece cere eee eee tenet en eH AR EHD He eH eb EO ee ER EEE HODES DEERE REESE ES 20.8

 

 

* Not separated from cells immediately.
Standard deviation from the mean 3.6 mam. Coefficient of variation 14.5 per cent.

SUMMARY

1. In cats dying from varied types of induced shock, the average con-
centration of potassium in the heart’s blood taken at the time of cardiac
arrest was 42.8 mgm. per cent (0.0109 M).

2. In dogs following intravenous injections of isotonic potassium in
lethal doses, the concentration amounted to 59.5 mgm. per cent (0.0152 M)

(table 1).

3. The average venous plasma potassium in sixty young human adults
was 17.2 mgm. per cent (0.0044 M) (table 2).
4. The average plasma potassium of cardiac blood taken at death was
29.8 mgm. per cent (0.0076 M) (table 3).

We wish to express our appreciation to both the attending and resident
staff of the hospital for their coéperation in securing the cardiac blood

samples.
340 J. SCUDDER, M. E. SMITH AND C. R. DREW

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