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Chapter VI

Battle Casualties in Korea, Studies of the Surgical Research Team, Volume I

Studies of the Response of the Autonomic Nervous System Following Combat Injury*

Captain Robert R. Stahl, MC, USAFR
Major Curtis P. Artz, MC, USA
Captain John M. Howard, MC, USAR
Fiorindo A. Simeone, M. D., F. A. C. S.

This study of the response of the autonomic nervous system of the battle casualty was part of a broad study of the systemic response to injury carried out by the Surgical Research Team of the United States Army on the Eastern Front in Korea during 1952 and 1953. It does not permit a complete description of the function of the autonomic nervous system following injury. Its purpose has been to evaluate the status of autonomic activity, primarily sympathetic activity, in the wounded man to the extent of determining whether there was autonomic hyperactivity, hypoactivity, or normal activity in the battle casualty at the time of resuscitation. It was hoped that the findings might explain some of the syndromes observed following injury and therapy.

Methods

The approach to the problem was to measure the digital skin temperature, pulse volume, and finger flow, plethysmographically before and after peripheral nerve block. This approach was selected in the belief that it provided the most sensitive available indices of sympathetic activity. The pulse volume and flow were determined from the finger tip of the fifth finger and the skin temperature was measured at the base of the fifth finger.

These determinations were made before and after unilateral ulnar nerve block. The ulnar denervation at the elbow was accomplished by infiltration with 2 to 5 cc. of 1 per cent procaine hydrochloride. Two injections of procaine were necessary to obtain satisfactory ulnar paralysis in some of the patients.

Two patients with post-traumatic hypertension were studied in detail. One of the patients received phentolamine and hexamethonium and the other sodium amytal during the studies. 


*Reprinted by permission from Surgery, Gynecology and Obstetrics 99: 595-613 (Nov.), 1954. Copyright 1954, The Franklin H. Martin Memorial Foundation.


99

Blood flow in the finger was measured by the venous occlusion method. From 5 to 10 separate determinations, with at least 30-second intervals between them, were made at each trial and the average results are reported. The average value was used in an attempt to be more precise since we noted, as has Burton, that the minute to minute flow is widely variable.

The records of pulse volume have been satisfactory but the finger flow determinations were not consistently obtainable on all patients because of apprehension and restlessness exhibited by certain of the casualties which resulted in frequent movements during the recordings. It is desirable to have the patient supine and for him to remain motionless during the recording.

Along with the determinations mentioned, clinical observations and historical data pertinent to each patient were tabulated. The temperature range of the room and the relative humidity were recorded during the study.

Each patient was lying on a litter which was placed on a litterframe during the study. The upper extremities were supported by pillows at the level of the heart. Every effort was made to make these patients comfortable. In warm environmental temperatures they were covered only by a towel whereas in cooler environments they were covered from the axillae downward with one or two blankets, depending on the patient's desire; the warmth created by the blankets could have interfered to a variable extent with full reflex vasoconstriction.

The plethysmograph consists of a low-pressure, volume-sensitive transducer and a sensitive multichannel amplifier recording system similar to that used in the Grass electro-encephalograph. The construction of the Grass transducers permits the use of air as a transmitting medium. The transducers are equipped with precision-made injectors so that calibration may be accomplished by the injection of 5 to 10 cu. mm. of air into the system. At maximal gain in the system a change in finger-tip volume of 1.0 cu. mm. results in a deflection of the pen of 20 mm. Electrically the system amplifies approximately 1.5 million times.7

The Grass finger oncometer consists of a light metal cylinder, closed at one end, and from which two small metal side tubes extend-one from the closed end of the cylinder and the other from the sidewall. Both of these outlet tubes connect with the inside of the chamber. The tube on the closed end of the cylinder was connected to a rubber tube leading to the pressure transducer. The tube on the side of the cylinder could be opened or closed at will so that pressure within the oncometer could be allowed to equilibrate with atmospheric pres-


100

sure. The oncometer was applied to the finger with kal-kord* which could be molded around the finger and cuff and produce an airtight seal without constriction.

The skin temperatures were recorded with specially designed Grass thermal resistors which when applied to the skin resulted in a very rapid response to temperature; these measurements were recorded on the same instrument.

Material. A total of 23 patients were studied in this series. All of these patients were battle casualties and the interval of time elapsing from injury until the time of study varied from 1.3 to 20 hours, the average being 5.7 hours. As far as could be determined these patients were normal healthy males prior to injury. Their ages varied from 18 to 33 years with an average of 22.5 years.

The causes of injury were limited to artillery and mortar fragments (16 patients, 69.5 per cent), small arms fire (5 patients, 21.8 per cent), and land mine explosions (2 patients, 8.7 per cent). Of the 23 patients studied, 13 or 56.6 per cent were Americans; 8 or 34.8 per cent were Koreans; 1 or 4.35 per cent Japanese-American; and 1 or 4.35 per cent Filipino.

The significant clinical observations and values for the plethysmographic determinations made on each patient are categorized in Table 1. 


*Kal-kord is a pliable, nonhardening, putty-like substance used for weather-stripping.


101-105

Table 1.
Observations on 23 Cases


106

Relationship Between Increase in Pulse Volume After Ulnar Nerve Block and Environmental Temperature

The relationship between the environmental temperature and the absolute values for pulse volume before and after ulnar block in a given patient is demonstrated in Figure 1. Thus it reflects the degree of increase resulting from peripheral ulnar nerve block.

The relationship between the environmental temperature and the increase in pulse volume after ulnar block (expressed as per cent increase) is demonstrated in Figure 2. The solid black line on this graph indicates the average percentage increase in pulse volume values for all patients studied in the various ranges of environmental temperature.

These data are categorically recorded as to the various ranges of environmental temperature studied in Table 2.

FIGURE 1.
Relationship between absolute values of pulse volume before
and after ulnar nerve block and environmental temperature.


107

Table 2. Relationship of Environmental Temperature and Blood Deficit to Pulse Volume Before and After Ulnar Nerve Block

Case No.

Average Environmental Temp. in Degrees F.

Initial Absolute Pulse Volume Before Ulnar Block in cu. mm./5 cc. of Finger

Absolute Pulse Volume After Block in cu. mm./5 cc. of Finger

Percentage Increase in Pulse Volume After Block

Blood Deficit

Morphine Sulfate Received Prior to Determination in mg.

60° to 70° F

1

60.0

1.0

4.55

355

Slight

30

6

66.0

0.70

4.30

514

Slight

10

13

68.3

0.80

2.35

194

Slight

15

3

70.3

0.60

4.45

642

Slight

15

70° to 75° F

18

70.7

1.35

5.65

319

Slight

Dose?

16

71.9

0.80

6.0

650

Moderate

---

14

73.1

0.35

6.55

1770

Slight

30

5

73.2

0.90

8.85

884

Slight

---

4

74.3

1.40

2.70

92.8

Slight

15

15

74.9

0.50

7.25

1350

Slight

---

75° to 80° F

12

75.7

3.65

4.80

31.5

Moderate

---

17

76.2

0.90

2.55

183

Slight

---

2

77.3

1.60

11.0

588

Slight

---

9

78.1

0.95

6.55

590

Slight

Dose?

80° to 85° F

11

80.5

0.55

3.20

481

Slight

10

22

81.9

1.75

19.0

985

Slight

---

8

82.4

4.25

14.75

247

Slight

---

23

83.8

3.75

5.25

40

Slight

30

85° to 90° F

21

85.5

3.15

3.60

14

None

15

19

86.0

1.90

5.70

200

Slight

Dose?

10

86.2

2.40

5.75

140

Slight

---

7

86.5

1.40

3.0

114

Slight

10

20

90.1

4.0

3.40

15 (decrease)

Severe

15


108

In the highest temperature ranges there is a tendency for the increases after block to be relatively small, which would be expected since at these higher temperatures patients would tend to be in a state nearer to the maximal vasodilatation level. This observation seems to be the only correlation in the data between the values for increase in pulse volume after ulnar nerve block and the environmental temperature.

FIGURE 2.
Relationship between per cent increase in pulse volume after ulnar nerve
block and the various ranges of environmental temperature in which patients were studied.

Relationship Between Initial Absolute Values for Pulse Volume and Environmental Temperature

The relationship between the initial absolute values for pulse volume before ulnar nerve block and the environmental temperature is demonstrated in Figure 3. Between 72.5° and 82.5° F there is a sudden marked increase in initial absolute pulse volume values with relatively smaller increases in environmental temperature. The solid black line indicates the average initial pulse volume values for all patients studied in a given range of environmental temperature.


109

FIGURE 3.
Relationship between the initial absolute values of pulse volume and
the various ranges of environmental temperature in which patients were studied.

On a physiologic basis it would appear logical to expect that higher ambient temperatures would result in release of vasomotor tone in the vessels supplying the skin of the finger tip with resulting vasodilatation and increase in pulse volume. From this graph one could possibly assume that the release of vasomotor tone in the skin vessels takes place rather rapidly between the temperatures of 72.5° and 82.5° F.

This is the only definite correlation which we were able to establish from the data on this graph.

Relationship Between the Administration of Morphine and the Initial Absolute Value for Pulse Volume

The dosages of morphine received by the patients with the values for the initial absolute pulse volumes prior to ulnar nerve block are


110

tabulated in Table 2 in which the cases are arranged according to the range of environmental temperature. The information regarding the administration of morphine was obtained from the emergency medical tag which was the only medical record accompanying patients to the hospital from more forward medical installations.

Morphine, as stated by Goodman and Gilman,3 even in therapeutic doses has been shown to cause dilatation of cutaneous vessels. However, if the initial absolute values for pulse volume before ulnar block are evaluated with regard to whether or not the patients received morphine, a correlation could not be established. If a correlation did exist, we would expect to find larger values for initial pulse volume in the group that received morphine. Fourteen or 61 per cent of the patients received morphine prior to study; the average initial absolute pulse volume value before ulnar block in this group was 1.55 cu. mm. per 5 cc. of finger. The average of the environmental temperatures in which this group of patients was studied was 76.7° F. Nine or 39 per cent of the patients received no morphine prior to study; the average initial absolute pulse volume value for this group was 1.85 cu. mm. per 5 cc. of finger. The average of the environmental temperatures in which this group of patients was studied was 77.7° F. There is no significant difference between these two groups.

Relationship Between Blood Deficit and Pulse Volume

The blood volume deficit was estimated clinically on the basis of extent of injury, the clinical observations on each patient, and the amount of blood required during resuscitation. Of the 23 patients studied, 1 or 4.35 per cent was considered to have no blood deficit because he was studied 111/2 hours postoperatively, was adequately transfused, and was hypertensive (Case 23). Nineteen, or 82.6 per cent, were estimated to have slight blood deficit; 2, or 8.7 per cent, moderate blood deficit; and 1, or 4.35 per cent, severe blood deficit.

The average values for initial absolute pulse volume before block and for per cent increase after block are categorized, according to the degree of blood deficit, as follows:

In the 1 patient with no blood deficit the initial absolute pulse volume was 3.15 cu. mm. per 5 cc. of finger, the increase after ulnar block 40 per cent; in the 19 patients with slight blood deficit the average initial absolute pulse volume was 1.40 cu. mm. per 5 cc. of finger, the average increase after block 509.9 per cent; in the 2 patients with moderate blood deficit the average initial absolute pulse volume was 2.25 cu. mm. per 5 cc. of finger, the average increase after block 340.8 per cent; in the 1 patient with severe blood deficit the initial absolute


111

pulse volume was 4 cu. mm. per 5 cc. of finger, the decrease after block 15 per cent.

In this series the number of patients with slight blood deficit was much larger than any of the other groups categorized on the basis of blood deficit. Thus a definite correlation could not be established between the amount of blood deficit prior to the study and the initial absolute value of pulse volume. Likewise a definite correlation could not be established between the degree of blood deficit and the percentage increase in pulse volume after nerve block. However, it should be noted that those patients with systolic blood pressures of 140 or more millimeters of mercury, all of whom had slight or no blood loss, showed relatively small increases in pulse volume after block. This phenomenon is particularly striking in Cases 7, 10, and 21 when the environmental temperature during the study was between 85.0° and 90.0° F. This suggests that in this relatively hypertensive group of patients a humoral agent might have been producing vasoconstriction so that nerve block would not release the vasomotor tone.

It should also be noted that Case 20 with severe blood loss was studied at an environmental temperature of 90° F and that the initial pulse volume was large. If reflex vasoconstriction occurs in shock, either this patient did not demonstrate the phenomenon, or the high environmental temperature overcame the effect.

Relationship Between Type of Injury and Pulse Volume

All of the patients were selected so that the significant wounds were either extremity or abdominal. Of the 23 patients studied, 16 or 69 per cent had extremity wounds and 7 or 31 per cent had abdominal wounds. The values for initial absolute pulse volume and per cent increase in pulse volume after nerve block, according to the type of injury incurred, are categorized in Table 3. There is no difference in the values for average initial absolute pulse volume or per cent increase in pulse volume after block between these two groups categorized on the basis of type of wound.

Relationship Between Initial Absolute Pulse Volume,
Increase in Pulse Volume After Block, and Systolic Blood Pressure

The patients are grouped according to the level of systolic blood pressure during the determinations in Table 4. Of the 23 patients studied, 20 or 87 per cent had systolic blood pressures above 100 mm. of mercury; 3 or 13 per cent of the patients had systolic blood pressures below 100 mm. of mercury. The average values for initial pulse


112

Table 3. Relationship Between Type of Injury and Pulse Volume

Case No.

Initial Absolute Pulse Volume before Ulnar Block in cu. mm./5 cc. of Finger

Per Cent Increase in Pulse Volume after Ulnar Block

Abdominal Wounds

2

1.60

588

11

0.55

481

12*

3.65

31.5

16*

0.80

650

17

0.90

183

19

1.90

200

22

1.75

985

Average

1.60

455.5

Extremity Wounds

1

1.0

355

3

0.60

642

4

1.40

92.8

5

0.90

884

6

0.70

514

7

1.40

114

8

4.25

247

9

0.95

590

10

2.40

140

13

0.80

194

14

0.35

1,770

15

0.50

1,350

18

1.35

319

20*

4.0

15 (decrease)

21*

3.15

14

23

3.75

40

Average

1.55

453.2

*Cases 12 and 16 of the abdominal group both experienced moderate blood deficit. Case 20 of the extremity group experienced severe blood deficit. Case 21 was considered to have no blood deficit at the time of the determinations. All of the other cases had slight blood deficit.


113

volume before block and the per cent increase in pulse volume after block in the two groups also appear in Table 4.

The relationship between percentage increase in pulse volume following ulnar nerve block and the systolic blood pressure is demon-

Table 4. Relationship Between Pulse Volume and Systolic Blood Pressure

Case No.

Initial Absolute Pulse Volume in cu. mm./5 cu. of Finger

Per Cent Increase in Pulse Volume after Ulnar Block

Systolic blood pressure below 100 mm. of mercury

16

0.80 (at 72° F)

650

20

4.0 (at 90° F)

15 (decrease)

22

1.75 (at 82° F)

985

Average

2.35

540

Systolic blood pressure above 100 mm. of mercury

1*

1.0

355

2

1.60

588

3

0.60

642

4*

1.40

92.8

5

0.90

884

6*

0.70

514

7*

1.40

114

8

4.25

247

9

0.95

590

10*

2.40

140

11

0.55

481

12†

3.65

31.5

13*

0.80

194

14

0.35

1,770

15*

0.50

1,350

17

0.90

183

18*

1.35

319

19

1.90

200

21*

3.15

14

23

3.75

40

Average

1.60

437.5

*Those patients who at some time before or during the study had some degree of systolic hypertension (140 or more mm. of mercury).
†Systolic blood pressure just 100 mm. of mercury at the time of the determination.


114

strated in Figure 4. Again it is emphasized that the patients in whom systolic blood pressure was 140 or more millimeters of mercury reacted with relatively small increases in pulse volume after peripheral ulnar nerve block.

The group of patients in whom systolic blood pressure fell below 100 mm. of mercury is so very small in comparison to the group in whom systolic pressure remained above 100 mm. that a correlation between pulse volume and systolic blood pressure is not justified.

FIGURE 4.
Relationship between per cent increase in pulse volume
after ulnar nerve block and systolic blood pressure.

Cases 12 and 16 both had moderate blood deficit; Case 20 had severe blood deficit. Cases 16 and 20 were both in the group in which systolic blood pressure was below 100 mm. of mercury. Case 12 had a systolic blood pressure of just 100 mm. of mercury at the time of the determination. Cases 12 and 20 were both studied at relatively high ambient temperatures.


115

Various types of blood pressure response were observed in this group of patients. The following categorizes the patients according to the type of systolic blood pressure* response:

1. Patients who were normotensive from the onset of injury until the completion of our studies without blood or fluid replacement-Cases 2, 5, 8, 9, 14, 17, 19, 23.

2. Patients who were originally normotensive but became mildly hypertensive with fluid or blood replacement-Cases 1, 13.

3. Patients who were hypertensive from the onset of injury until completion of our studies without fluid or blood replacement-Cases 4, 6, 7, 10, 18.

4. Patients who were at first hypotensive but became hypertensive with blood and fluid replacement; our studies were made during the hypertensive period-Cases 15, 21.

5. Patient who was at first hypotensive but became normotensive with fluid or blood replacement-Case 11.

6. Patients who were hypotensive from the onset of injury until completion of our studies-Cases 12, 16, 20, 22.

Post-traumatic Hypertension

Two of the patients in the hypertensive group (Table 4) were studied in detail. Each of these patients is reported here in detail with case summaries and charts depicting the results of the study.

Case 4. A 21-year-old colored male was shot just outside his company area with an M1 rifle at 2400 hours on May 10, 1953. He arrived at the battalion aid station at 0030 hours on May 11, 1953, where his wounds were cleaned and dressed and he received penicillin, tetanus toxoid, and 15 mg. of morphine sulfate. He arrived at the clearing station at 0750 hours where he was again given 15 mg. of morphine sulfate. He was then evacuated to the 46th Army Surgical Hospital by helicopter, arriving there at 1020 on May 11, 1953.

On admission he was found to have an evulsive wound of the right lower thigh with associated fracture of the right femur. The patient was hypertensive on admission and remained so throughout the entire period preceding surgery. His skin was warm; nailbeds were pink; pulse was of good volume; he complained of slight intermittent pain in the right thigh at the site of injury. His total blood loss was estimated to be no more than 200 to 300 cc.

The interval of time elapsing between injury and the onset of our experimental procedure was approximately 101/2 hours. The duration of the study was approximately 5 hours.

Following a right ulnar nerve block the maximal percentage increase in pulse volume bilaterally was 93 per cent. However, during this period of time the room temperature increased from 73.4° to 75.2° F and the skin temperatures on both the blocked and unblocked sides increased to 15 degrees in the interval of time from the control tracings until the tracings were repeated after ulnar nerve block. It is obvious from these findings that the patient was in the process of stabilization in the presence of a somewhat changing environmental temperature. Consequently it is impossible to evaluate what 


*Patients who in the supine position had systolic blood pressures of 140 mm. of mercury and above were considered to be hypertensive.


116

portion of the increase in pulse volume and skin temperature on the right side could be attributed to the right ulnar nerve block; the evaluation would be impossible because of the many variables involved.

At one point in the procedure 5 mg. of phentolamine was given intravenously. There was no appreciable change in the pulse volume on either the right or left sides after the administration of this drug. There was a slight transient drop in the diastolic blood pressure but little change in the systolic pressure.

At another point in the procedure 25 mg. of hexamethonium bromide was given intravenously at a rapid rate. The administration of this drug resulted in a maximal percentage increase in pulse volume in the left fifth finger of 24 per cent. There was an associated abrupt fall in both systolic and diastolic blood pressure (190/98 to 90/0) and an increase in pulse rate from 116 to 150 per minute. The patient complained of vertigo and it was necessary to tilt him head-down for a few minutes. The increase in digital pulse volume produced by this drug was very transient. The markedly hypotensive effects lasted for about 5 minutes, and then both systolic and diastolic pressures climbed gradually to the premedication level over a period of about 13 to 15 minutes.

During the experimental procedure the patient was covered with one wool blanket from the chest to his feet. After the administration of phentolamine and hexamethonium bromide blood pressures were taken at minute intervals by the cuff method on the right arm. The mechanics of the inflation of the blood pressure cuff tends to invalidate all plethysmographic determinations recorded from the right side because of the intermittent interruption of blood flow.

During anesthesia with pentothal the patient experienced another episode of hypotension. This tends to substantiate the thoughts of others who maintain that pentothal is a sympathetic ganglionic depressant agent. In this case there was similarity between the response to a known ganglionic blocking agent, hexamethonium, and the response to pentothal. The hypotensive phase occurring simultaneously with pentothal administration subsided only when the anesthetic agent was changed to gas, oxygen, and ether. The duration of anesthesia and surgery was approximately 1 hour, 45 minutes.

The accompanying graph in Figure 5 depicts the results of the determinations.

Case 21. A 23-year-old colored male was injured by mortar fragments on July 18, 1953, at approximately 1330 hours. Blood pressure recorded at the battalion aid station was 50/40. He received 200 cc. of serum albumin and 1,000 cc. of dextran in addition to 15 mg. of morphine sulfate at the aid station. The patient was evacuated by helicopter and arrived at the 46th Army Surgical Hospital at approximately 1600 hours on July 18, 1953.

Examination at the hospital revealed a traumatic amputation of the right lower leg and multiple large penetrating wounds of the left lower leg and small penetrating wounds of the right arm. Blood pressure was 70/30 and pulse 144 per minute. Preoperatively the patient received 3,000 cc. of whole blood. At 1940 hours he was taken to surgery at which time both legs were amputated just below the knee joint. Surgery ended at 2140 hours; the patient received 2,500 cc. of whole blood during the surgical procedure.

Prior to surgery blood pressure ranged from 70 to 138 systolic and from 30 to 80 diastolic. Following surgery the patient's blood pressure began to rise gradually to reach hypertensive levels; at the eighth postoperative hour his blood pressure was 184/108. The studies were begun at approximately 111/2 hours following the completion of surgery at which time the blood pressure was 164/102. At the time of the study the patient was moderately apprehen-


117

FIGURE 5.
Case 4. Graphic illustration of the response of a hypertensive battle casualty who was given
phentolamine and hexamethonium bromide.


118

sive and emotional about the loss of his legs. His skin was warm to palpation; color was normal; he was perspiring profusely; and the pulse was rapid and full.

Pulse volumes and finger flows were recorded bilaterally from the tips of the fifth finger. Initial values on the right and left fingers for pulse volume were 3.20 and 3.75 cu. mm. per 5 cc. of finger, respectively. The values following right ulnar nerve block were 3.60 and 3.75 cu. mm. per 5 cc. of finger, respectively. The slight increase on the right following right ulnar nerve block is insignificant. Following the nerve block there was complete anesthesia over the sensory distribution of the ulnar nerve in the hand. Finger flows actually decreased bilaterally after nerve block without any appreciable decrease in the blood pressure or pulse pressure.

Following this first part of the study the patient was given 225 mg. of sodium amytal intramuscularly. The patient became quite lethargic and began to sleep soundly. There was only slight decrease in systolic pressure (14 mm. of mercury) over the period of an hour following the administration of sodium amytal and then the pressure returned gradually to its original level. Pulse volumes at this time showed no appreciable consistent change as a result of sodium amytal sedation.

The environmental temperature during this study ranged from 84.4° to 90.3° F. These studies reveal that this man, even though hypertensive, did not show evidence of vasoconstriction in the skin and subcutaneous tissue as measured in the finger tip but, rather, was initially relatively vasodilated as one would expect a normal man to be in a very warm environment. Certainly if this patient had arteriolar constriction contributing to his hypertension it was not apparent in the skin and subcutaneous tissue of the finger tips.

The accompanying chart in Figure 6 depicts the results of the significant determinations during this study.

Relationship Between Initial Skin Temperature Prior to Ulnar Block and Environmental Temperature

Fourteen of the twenty-three patients studied were considered to have skin temperature responses which were satisfactory for analysis. The initial skin temperatures at the base of the fifth finger on the side studied are plotted against the environmental temperature at the time in Figure 7. It will be observed that any point on the solid diagonal line represents a skin and an environmental temperature of the same magnitude. This line describes the behavior of the skin temperature under conditions of changing environmental temperature of a tissue which would theoretically be devoid of circulation, i. e., the skin temperature would be the same as that of the environment if sufficient time elapsed for equilibrium to be established. From this graph it will be seen that 11 of the 14 patients had initial skin temperatures which were above this line and indicating that the skin was warmer than the environment at the time of the determination. Three of the fourteen patients (Cases 14, 15, and 17) had skin temperatures slightly less than the environmental temperature. This could result


119

FIGURE 6.
Case 21. Graphic illustration of the response of a hypertensive
battle casualty who was given sodium amytal.


120

only from perspiration and cooling due to evaporation from the skin surface or, possibly, from the fact that the patient was brought from a cool to a warm environment and had not reached equilibrium with the new environment. Cooling of the skin surface by evaporation or perspiration would tend to suggest that there was some degree of hyperactivity of the sympathetic nervous system. However, only 3 of the 14 patients demonstrated the phenomenon, all of which were considered to be in a state of slight blood deficit with systolic blood pressure above 100 mm. of mercury at the time of the skin temperature determination. One of these three patients became mildly hypertensive during the study.

The values depicted in Figure 7 are found in the data recorded in Table 5.

FIGURE 7.
Relationship between skin temperature before
ulnar nerve block and environmental temperature.


121

Table 5. Relationship Between Skin Temperature and Environmental Temperature

Case No.

Environmental Temperature

Skin Temperature prior to Block at Base of 5th Finger

Skin Temperature after Ulnar Block

Blood Deficit

Systolic Blood Pressure at Time of Determination

1

60.3

72.6

82.6

Slight

132

2

77.0

81.7

85.5

Slight

130

3

69.6

77.2

93.7

Slight

128

5

73.5

78.5

100.2

Slight

120

6

65.7

73.8

81.8

Slight

150

9

78.8

87.3

97.2

Slight

110

11

81.0

93.1

95.8

Slight

114

12

75.6

87.6

89.1

Moderate

96

13

68.2

75.8

84.6

Slight

142

14

73.8

71.9

89.5

Slight

120

15

74.7

74.5

82.0

Slight

140

16

71.2

73.8

93.6

Moderate

98

17

76.5

72.5

79.3

Slight

118

18

70.2

74.6

94.6

Slight

140

All temperatures in degrees Fahrenheit.

Relationship Between Initial Skin Temperature Prior to Ulnar Nerve Block and Systolic Blood Pressure

The initial values for skin temperatures before ulnar block are plotted against the systolic blood pressure at the time of the temperature determination in Figure 8. Only 2 of the 14 patients had systolic blood pressures which were below 100 mm. of mercury at the time of the determination (Cases 12 and 16). Both of these patients were considered to be in a state of moderate blood loss. The other 12 patients had slight blood deficit and all had systolic blood pressures over 100 mm. of mercury.

The graph in Figure 8 would indicate that there was a tendency for the patients with the highest systolic blood pressures to have the lower values for initial skin temperature before ulnar nerve block. Perhaps this indicates that there is some excessive degree of vasoconstriction in the vessels of the finger tip in this somewhat hypertensive group of patients.


122

FIGURE 8.
Relationship between skin temperature before
ulnar nerve block and systolic blood pressure.

Relationship Between Increase in Skin Temperature After UInar Block and Environmental Temperature

The values for skin temperature at the base of the fifth finger before and after ulnar nerve block are plotted against the environmental temperature in Figure 9. The vertical lines connect the determinations before and after block in a given patient and thus indicate the increase in temperature resulting from sympathetic paralysis. There is a tendency for those cases which were studied at higher environmental temperatures to show smaller increases in skin temperature after ulnar block. Three exceptions to this observation were Cases 1, 6, and 13 which were studied in a range of environmental temperature from 60° to 70° F. All three of these patients showed small increases after ulnar block and all had systolic blood pressures of 140 or more millimeters of mercury. These same three patients revealed relatively small increases in pulse volume after block. A possible explanation for the relatively small temperature and small pulse volume increases after sympathetic paralysis is that a circulating vasopressor substance could have maintained these peripheral vessels in a state


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FIGURE 9.
Relationship between skin temperature before and
after ulnar nerve block and environmental temperature.

of relative vasoconstriction following temporary denervation of the blood vessels.

Discussion

In the normal human it has been shown by Morton and Scott5 that the normal maximal vasodilatation level for skin temperature after sympathectomy, procaine nerve block, or spinal anesthesia is approximately 95° F. If it is assumed that the patients in this series had normal blood vessels and that satisfactory peripheral ulnar nerve blocks were obtained, the attainment of maximal vasodilatation would indicate that the patient had a normal blood volume and normal cardiac output. All of these patients had complete anesthesia in the skin of the hand innervated by the ulnar nerve following ulnar nerve block; thus, the belief was that the blocks were successful. Failure to obtain maximal vasodilatation in the vessels of the fifth finger after sympathetic paralysis indicates that there was a deficit of blood


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reaching the finger tip which could be due to oligemia and decreased cardiac output. Thus the degree to which these patients failed to reach the maximal vasodilatation level (95° F) after sympathetic paralysis should reflect the degree of oligemia and decreased cardiac output unless circulating vasopressor substances were responsible for vasoconstriction in these vessels. The degree to which the skin temperature at the base of the fifth finger failed to reach the maximal vasodilatation level is expressed by the ratio of experimental value for skin temperature after ulnar nerve block/theoretic maximal value (95° F) in Figures 10 and 11. The solid black horizontal line represents a ratio of 0.95 or a skin temperature of approximately 90° F. Thus it is assumed, for purposes of discussion, that in the cases with ratios of 0.95 to 1.00 (skin temperatures of 90° to 95° F after ulnar nerve block) maximal vasodilatation had occurred. Thus all the ratios which were below this line represent patients in whom maximal vasodilatation was not present after ulnar nerve block. The relationship between this ratio and the environmental temperature is demonstrated in Figure 10. The relationship between this ratio and the systolic blood pressure is demonstrated in Figure 11. The data for these graphs are presented in Table 6.

Table 6. Relationship of Skin Temperature After Block to Theoretic Maximal

Case No.

Skin Temp. after Ulnar Block in Degrees F

Ratio-Experimental Skin Temp. after Ulnar Block/Theoretic Maximal (95°)

Systolic Blood Pressure in mm. of Mercury

Blood Deficit

Environmental Temp.

1

82.6

87

142*

Slight

60.1

2

85.5

90

134

Slight

77.9

3

93.7

98.6

128

Slight

71.0

5

100.2

105.4

120

Slight

72.9

6

81.8

86.1

140*

Slight

66.3

9

97.2

102

106

Slight

77.4

11

95.8

101

120

Slight

79.9

12

89.1

93.8

100

Moderate

75.8

13

84.6

89.0

140*

Slight

68.3

14

89.5

94.2

128

Slight

72.0

15

82.0

86.3

144*

Slight

75.2

16

93.6

98.5

98

Moderate

72.7

17

79.3

83.5

112

Slight

75.9

18

94.6

99.6

144*

Slight

71.2

*Indicates those patients who became hypertensive (systolic pressure 140 or more millimeters of mercury) prior to or during the determinations.


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FIGURE 10.
Relationship between the ratio of experimental value of the skin temperature
after ulnar nerve block/theoretic maximal value and environmental temperature.

Of the 14 patients in whom skin temperature response was evaluated, 8 or 57 per cent of the patients failed to reach the maximal vasodilatation level after ulnar block. Only one of these patients (Case 12) suffered moderate blood deficit; all of the remaining seven patients had only slight blood deficit at the time of the determination. Four of these eight patients had systolic blood pressures which were considered to be hypertensive at the time of the determination (Cases 1, 6, 13, and 15). In this hypertensive group, in which blood deficit was only slight, a circulating vasopressor substance could possibly be responsible for their failure to reach the maximal vasodilatation level following paralysis of the sympathetic supply to the vessels in the fifth finger tip; this, of course, is only speculation.

There were three other cases with slight blood loss which failed to reach the maximal vasodilatation level after sympathetic block (Cases 2, 14, and 17). All of these three patients were normotensive on admission to the hospital and remained normotensive through the completion of the studies without fluid or blood replacement. There is no apparent explanation for their failure to reach the maximal vasodilatation level unless it be an expression of oligemia.


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FIGURE 11.
Relationship between the ratio of experimental value of skin temperature
after ulnar nerve block/theoretic maximal value and the environmental temperature.

A correlation could not be established between the environmental temperature and whether or not patients reached the maximal vasodilatation level.

At present it is not possible to express definitely whether or not a given patient is vasoconstricted from observation of the absolute value of pulse volume. The range of pulse volume values at varying degrees of environmental temperature is unknown. It is conceivable that the range of values at any given temperature might be quite wide. Thus it is a decided disadvantage not to have baseline values with which to compare the patients in this series. Consequently there were limitations in the selection of a yardstick by which autonomic activity could be evaluated in these patients. Since the initial absolute value for pulse volume is somewhat of a variable, the degree of increase after sympathetic paralysis was chosen as a measure of autonomic activity. This is open to criticism because it must be assumed that a given degree of oligemia or a certain deficit of cardiac output will have the same relative effect on the rate of blood flow during vasoconstriction as during vasodilatation. There is no evidence at


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present upon which to base this assumption. Although the increase in pulse volume and skin temperature resulting from sympathetic paralysis is a measure of sympathetic activity in a given patient, one patient would not be comparable to another if there were great variability between patients in the degree of blood volume deficit. In this series of 23 patients, however, it was estimated clinically that 19 were in a state of slight blood deficit and I had no blood deficit; of the 3 remaining patients, 2 were in a state of moderate blood deficit and 1 in a state of severe blood deficit. It appears that difference in degree of oligemia was not a significant factor in most of these patients and the degree of increase in pulse volume and skin temperature after ulnar block should be a reasonably satisfactory approximation of vasomotor activity. The initial vasomotor activity as manifested by increase in pulse volume and skin temperature after sympathetic paralysis would also be a function of the initial environmental temperature.

The maximal vasodilatation level for pulse volume is not definitely established. An attempt was made to establish a theoretic maximal value from pulse volume studies, obtained by Simeone and associates,6 on 33 patients with normal circulation. These pulse volume studies had been made from the fifth finger on normal upper extremities after ulnar nerve block. It was found that the pulse volume values for these 33 patients, who were maximally vasodilated, were extremely variable. However, as suggested by one of us (F. A. S.), 10 cu. mm. per 5 cc. of finger have been used as the approximate theoretic maximal value for pulse volume after sympathetic paralysis.

The degree to which pulse volume failed to reach the maximal vasodilatation level is expressed by the ratio of experimental value for pulse volume after ulnar nerve block/theoretic maximal value (10 cu. mm./5 cc. of part) in Figures 12 and 13. The solid black line on these graphs represents a ratio of 1.00. The relationship between this ratio and the environmental temperature is demonstrated in Figure 12. The relationship between this ratio and the systolic blood pressure is demonstrated in Figure 13. Data from all 23 patients, relative to these graphs, are in Table 7.

All but three of the patients failed to reach the maximal vasodilatation level for pulse volume. The existence of a deficit by which patients failed to reach the maximal vasodilatation level even at high environmental temperatures indicates that the deficit is not due to unsatisfactory peripheral ulnar nerve blocks. Therefore, the deficit would indicate that these patients either had oligemia and decreased cardiac output or had a humoral vasopressor substance in their circulation. Unfortunately, the effects of oligemia per se could not be sepa-


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Table 7. Relationship of Pulse Volume After Block to Theoretic Maximal

Case No.

Pulse Volume after Block in cu. mm. per 5 cc. of Finger

Ratio-Pulse Volume after Block/Theoretic Maximal (10 cu. mm. per 5 cc. of Finger)

Systolic Blood Pressure

Blood Deficit

Environmental Temperature at Time of Pulse Volume Determination

1

4.55

0.46

142*

Slight

60.1

2

11.0

1.1

124

Slight

77.7

3

4.45

0.45

138

Slight

71.0

4

2.70

0.27

160*

Slight

75.2

5

8.85

0.89

120

Slight

72.9

6

4.30

0.43

144*

Slight

66.3

7

3.0

0.30

150*

Slight

85.5

8

14.75

1.48

116

Slight

82.6

9

6.55

0.66

106

Slight

77.4

10

5.75

0.58

140*

Slight

87.4

11

3.20

0.32

110

Slight

79.9

12

4.80

0.48

100

Moderate

75.8

13

2.35

0.24

140*

Slight

68.3

14

6.55

0.66

128

Slight

72.0

15

7.25

0.73

144*

Slight

75.2

16

6.0

0.60

96

Moderate

72.7

17

2.55

0.26

112

Slight

75.9

18

5.65

0.57

144*

Slight

71.2

19

5.70

0.57

124

Slight

86.0

20

3.40

0.34

70

Severe

90.3

21

3.60

0.36

160*

None

86.7

22

19.0

1.9

96

Slight

82.7

23

5.25

0.53

120

Slight

83.8

*Indicates patients who bacame hypertensive (systolic pressure 140 or more millimeters of mercury) at some time prior to or during the study.

rated from the possible effects of humoral agents. It seems most likely that a humoral vasopressor substance was operating to prevent large increases in pulse volume after ulnar block and to produce failure to reach the maximal vasodilatation level in the nine hypertensive patients. Since Regitine had very little effect when used in Case 4, it is suggestive, as Emlet2 and Meier4 and their associates have pointed out, that if a humoral vasopressor agent was active, it was probably not adrenalin or noradrenalin.

The large degree by which most of these patients failed to reach the maximal vasodilatation level for both skin temperature and pulse volume after sympathetic paralysis would indicate that this deficit was not attributable to overactivity of the sympathetic nerves per se


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FIGURE 12.
Relationship between the ratio of experimental value of pulse volume
after ulnar nerve block/theoretic maximal value and the environmental temperature.

FIGURE 13.
Relationship between the ratio of experimental value of pulse volume
after ulnar nerve block/theoretic maximal value and the systolic blood pressure.


130

but, rather, suggests that oligemia and decreased cardiac output or humoral vasoconstrictors were more important factors. The peripheral pallor seen in injured patients cannot be attributed entirely to exaggerated nervous activity. It has also been observed in Figure 9 that all but 3 of the 14 patients in whom skin temperatures were evaluated had an initial skin temperature greater than that of the environment. This finding would tend to indicate that there was no extraordinary overactivity of the sympathetic nerves.

From this study it can definitely be concluded that the sympathetic nervous system was functionally active in these patients and that sympathetic activity was not obliterated by the traumatic and circulatory insults experienced. However, the degree of activity in effect, i. e., normal activity, hypoactivity, or hyperactivity, could not be determined.

It must be realized that facilities did not exist in the field whereby environmental temperature and relative humidity could be controlled at a constant level during the period of study. However, should a constant temperature environment have been available, its proper utilization would have been impractical because of the short interval of time allowed for study on a wounded casualty prior to definitive surgery; a patient must be allowed to stabilize in a constant temperature environment for an hour or more before the constant temperature environment can be considered as a valuable control. When attempting to perform acute studies this is fraught with difficulties because of changes which could possibly occur in the individual as a result of the long period of stabilization.

Front a hemodynamic point of view it must be remembered that these plethysmographic studies reveal only changes in blood flow and pulse volume in the skin and subcutaneous tissue of the finger tip. These must not be misconstrued to be representative of flow or flow changes which might have been present in other vascular beds such as muscular, splanchnic, coronary, or pulmonary. The circulatory changes which occurred in these other vascular areas may have been quite different and independent from those occurring in skin and subcutaneous tissue of the finger tip.

Summary

1. Pulse volume and skin temperature determinations were made before and after ulnar nerve block from the fifth finger tip of 23 battle casualties admitted to a Mobile Army Surgical Hospital in Korea.

2. Patients who were studied in the higher ranges of environmental temperature revealed smaller increases in pulse volume after ulnar nerve block.


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3. Patients studied in the higher ranges of environmental temperature revealed larger initial absolute values for pulse volume.

4. A correlation could not be established between the initial absolute pulse volume value and the administration of morphine prior to the study.

5. Most of the patients studied, when evaluated clinically, were considered to be in a state of slight blood volume deficit. The patients who were more oligemic were too few to compare with this larger group. Consequently, a correlation could not be established between either the initial absolute pulse volume value or the degree of increase in pulse volume after nerve block and the degree of blood volume deficit. However, the patients whose systolic blood pressures were 140 or more millimeters of mercury, all of whom had slight or no blood loss, showed relatively small increases in pulse volume after nerve block.

6. A correlation could not be established between either the initial absolute pulse volume value or the degree of increase after ulnar nerve block and the type of injury, i. e., abdominal or extremity.

7. A correlation could not be established between either the initial absolute pulse volume or the increase in pulse volume after ulnar nerve block and the systolic blood pressure. Six types of blood pressure response were observed in these patients and these are recorded.

8. The case reports and studies on two patients with post-traumatic hypertension are presented in detail.

9. Fourteen patients had skin temperature responses which were satisfactory for evaluation. All but three of these patients had skin temperatures before ulnar nerve block which were greater than the environmental temperature.

10. There was a tendency for those patients with the highest systolic blood pressures to have lower values for initial absolute temperature before ulnar nerve block.

11. There was a tendency for smaller increases in skin temperature after ulnar nerve block to occur in those patients studied at higher environmental temperatures.

12. The large degree by which these patients failed to reach the theoretic maximal vasodilatation level after ulnar block, for both skin temperature and pulse volume, suggests that oligemia and decreased cardiac output were largely responsible for this deficit. However, in the nine hypertensive patients, all of whom had slight or no blood loss, the possibility of a hormonal vasoconstrictor substance being responsible for the major portion of the deficit is discussed. It was not possible to separate the components of the deficit into that attributable to oligemia and decreased cardiac output and that due to humoral vasoconstriction.


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13. From this study it can be definitely concluded that the sympathetic nervous system is functionally active in battle casualties. The traumatic and circulatory insults experienced by these patients did not obliterate the functional activity of the sympathetic nervous system. It was not possible to determine the degree of functional activity of the sympathetics which was operative, i. e., normal activity, hypoactivity, or hyperactivity.

References

1. Burton, A. C.: The Range and Variability of the Blood Flow in the Human Fingers and the Vasomotor Regulation of Body Temperature. Am. J. Physiol. 127: 437, 1939.

2. Emlet, J. R., Grimson, K. S., and Metcalf, B. H.: Comparison of Blocking Actions of Regitine and Benodaine Against Effects of Injected Levoepinephrine and Levoartenol. J. Pharm. 101: 10, 1951.

3. Goodman, L., and Gilman, A.: The Pharmacological Basis of Therapeutics, p. 201. The Macmillan Co., New York, 1941.

4. Meier, R., Yonkman, F. F., Craver, B. N., and Gross, F.: A New Imidazoline Derivative with Marked Adrenolytic Properties. Proc. Soc. Exper. Biol., N. Y. 71: 10, 1949.

5. Morton, J. J., and Scott, W. J. M.: A Study of the Measurement of Sympathetic Vasoconstrictor Activity Observed in the Lower Extremities. J. Clin. Invest. 9: 235, 1930.

6. Simeone, F. A.: Personal communication.

7. Simeone, F. A., Cranley, J. J., Grass, A. M., Linton, R. R., and Lynn, R. B.: An Oscillographic Plethysmograph Using a New Type of Transducer. Science 116: 355, 1952.