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SECTION I
GENERAL SURGERY
CHAPTER VI
ANESTHESIA
The problems presented l)y the wounded in their relation to anesthesia may be grouped (1) according to the general condition of the soldier and the length of time between the receipt of his injury and operation; or (2) according to the type of wound and the part of the body injured. Thus, in the front line hospitals men still suffering from shock or hemorrhage might require an immediate operation, and even the lightly wounded, on account of exposure, fatigue, cold, possibly lung involvements, bronchitis in particular, would be but little able to endure well the dangers of an inhalation anesthetic. Under each of these varying, conditions-at the front-line station, the lightly wounded but exhausted soldier and the seriously wounded soldier in shock; and at the base hospital, the soldier who has arrived hours or days after his injury was received in whom infection has mounted and even gas gangrene may have developed-what is the anesthetic method of choice, and does the part involved also influence the choice of the anesthetic?
During the World War the choice of anesthesia lay among chloroform and ether and nitrous oxide-oxygen as general anesthetics, spinal anesthesia, and block or regional anesthesia or local anesthesia. In the first year of the European War the paramount value of nitrous oxide and oxygen anesthesia in operations upon the seriously wounded, whatever their degree of exhaustion, was demonstrated by American anesthetists attached to the Western Reserve University Unit in service at the American Ambulance at Neuilly,1 and one of the nurse anesthetists, by the special request of the French and English medical officers, remained in France after the return of this unit to America to give instruction in the technique of the administration of this anesthetic.
The extension of confidence in the value of nitrous oxide-oxygen in military surgery was attested by the conclusions adopted by the second session of the Interallied Surgical Conference held in Paris early in 1917, which was attended by delegates from England, Belgium, France, Italy, Japan, Portugal, and Serbia. In the various sections of these conclusions appear the following statements: 2
V. Treatment of gaseous gangrene.-Anesthesia by means of nitrous oxide with oxygen is considered the best; when this is not to be had, ether may be substituted.
VI. Traumatic shock.-Local anesthesia combined with general anesthesia by means of nitrous oxide is the best. Next to this ether appears to be the least harmful. Spinal injections have produced varying results according to the surgeons employing them, especially in amputations of the lower limbs. The use of chloroform is dangerous.
VII. Amputations.-In the case of serious shock, the use of nitrous oxide and oxygen is desirable; ether is the next best anesthetic. Only in the case of cerebral wounds is any other anesthetic method advised.
XIV. Cerebral wounds.-Local anesthesia is preferred for the operation. The sitting posture tends to diminish hemorrhage and is easily maintained in secondary or delayed operations.
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At a later meeting of the Interallied Surgical Conference, at which delegates from the United States and from Russia were present, as also from the countries listed above, similar conclusions were adopted.3
FIG. 98.- Nitrous oxide manufacturing plant. Captured German cylinders in foreground, converted for use in nitrous oxide service. One-half million gallons of nitrous oxide ready for shipment to various American Army hospitals
When the first base hospital unit of the United States Army to be called into service (Base Hospital No. 4, the Lakeside Unit) left for France it was
FIG. 99.- Storage building, office, and laboratory of nitrous oxide manufacturing plant. Dimensions, 50 hy 75 feet, housing 700 tons of ammonium nitrate
equipped with what then appeared would be an adequate supply of nitrous oxide gas and apparatus for its administration.4 During the summer of 1917 the surgeons of this unit had opportunities of testing the comparative value
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FIG. 100.- Motors of 25 horsepower, used to drive compressors
FIG. 101.-Detail of compressors. Each unit was capable of ompressing 10,000 gallons daily
FIG. 102- Partial view of retort room. Each retort was capable of producing 5,010 gallons per 8-hour run. The retorts numbered 30
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of nitrous oxide, of ether, and of spinal anesthesia att a base hospital at Rouen (No. 9 General Hospital, British Expeditionary Forces) and at British casualty clearing stations in Flanders.5 Almost immediately inquiries were made by both English and French officers as to the possibility of securing an adequate supply of nitrous oxide, and it became evident that the supply brought over by this unit would soon be exhausted and the and the English supply was inadequate for their own needs. An immediate request was there therefore sent to the American Red Cross at home, and the matter was taken up with the Red Cross representatives in France, with the result that the American Red Cross appropriated funds for the purpose.6
FIG. 103.- Drip bottles and wash bottles which were connected with the retorts shown in Figure 102
With the funds so secured a plant was manufactured. It had a capacity of 125,000 gallons per eight-hour operation and was the largest in the world at the time of its construction. It was completed, tested, approved, and shipped from Cleveland early in January, 1918; but, owing to the exigencies of transport, the shipment was lost track of after it left New York and did not reach its destination in France until May 30, 1918. No further time was lost, however. Several men trained in the manufacture of gas, who had been released from the home plant to take charge of the assembling and operation of the plant in France, within six weeks-two weeks less than the estimated time for erection-had the plant ready for operation. Unfotunately, there was
FIG 104.- Military balloon, used to store gas. This took the place of the usual steel gasometers.
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again a brief delay due to a shortage of cylinders, but this was soon overcome by the acquisition of a number of captured German cylinders which were converted for our use. The plant was then in continuous operation until about the first of January, 1919, and thereafter continued to operate intermittently for about three months, after which it was taken over by the Salvage Corps.
CRITERIA FOR THE CHOICE OF METHOD
Before indicating the choice of anesthetic method in different types of cases it may be well to give here the evidence upon which the assertion is based that nitrous oxide-oxygen in the hands of a skilled anesthetist is the anesthetic of choice for the wounded soldier, in particular for the soldier in shock or exhaustion.
As has been stated above, the choice of anesthetic lies among the inhalation anesthetics, the lipoid solvents, ether and chloroform, and nitrous oxide-oxygen, and the various agents employed in spinal, regional, or local anesthesia. In making a choice we must know (a) what damage, if any, is caused by the anesthetic per se; and (b) what protection, if any, is offered by the anesthetic per se.
INHALATION ANESTHESIA
ETHER AND CHLOROFORM
In normal animals and normal men inhalation anesthetics, chloroform and ether more markedly than nitrous oxide, cause increased hydrogen-ion concentration of the blood-acidosis--during and roughly for about one hour after anesthesia. Protracted ether or chloroform anesthesia causes cytologic changes in the cells of the brain, the liver, and the adrenals identical with those resulting from other causes of exhaustion. After from four to six hours of continuous ether anesthesia many animals die; some never regain consciousness, but die within the first 24 hours. In the extensive studies of shock, hemorrhage, and gas infection made (by Lieut. Col. W. B. Cannon, M. C., and his coworkers7) at the Central Medical Department Laboratory, A. E. F., at Dijon, France, which have been continued in the laboratories of physiology of the Harvard Medical School,8 it was found that "the administration of ether, from its very beginning, results in a depression of the heart and a decrease in its output, which is sufficient to account for the fall in pressure in both the normal and the shocked animals"; that in normal animals "the inhalation of strong ether results in a sudden drop in the arterial pressure which is quite temporary"; while "in the shocked animal there is no recovery of the blood pressure after the primary fall and the pressure continues to fall to zero even before the eye reflex disappears." In contradistinction to the above observations these investigators found that "nitrous oxide and oxygen, in the most favorable proportions, can be administered to the shocked animal without causing more than a slight drop in blood pressure." They state, further, that "The condition of ether sensitiveness is brought about by any circumstances which tend to depress the general condition of the animal such as low blood pressure, hemorrhage, severe operations, or the injection of acid into the circulation"--a conclusion of immediate and vital significance in its relation to the choice of anesthetic for the wounded soldier.
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Ether and chloroform actively contribute to shock and exhaustion. They should be given evenly and lightly, therefore, as by the excellent Shipway apparatus, which is undoubtedly superior to the open-drop method. Marshall has shown that patients may apparently do well during ether anesthesia but
CHART I.- The effect of intravenous ether on the pulse and blood pressure. (By courtesy of Capt. Geoffrey Marshall, R. A. M. C.)
do badly afterwards; but that they do well both during and after nitrous oxide-oxygen anesthesia.9 From the patient's viewpoint, nitrous oxide-oxygen is the choice.
NITROUS OXIDE-OXYGEN
Nitrous oxide-oxygen anesthesia is light and gives less muscular relaxation than ether or chloroform. Special training in its administration is absolutely
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required, for it is technically the most difficult of all anesthetics to administer safely, although its administration is facilitated by recent improvements in the apparatus. These disadvantages, however, are far outweighed by its advantages as compared with ether or chloroform. It is quick in its action; is pleasant to take; recovery is immediate; it produces no nausea; it is protective, strongly protective against the shock of operation; for many minor operations it produces a pleasant analgesia in which pain is abolished while consciousness is retained; it can be given under positive pressure when desired, as
CHART II.- Comparative effects of ether and nitrous oxide in thigh amputations, as indicated by the pulse and blood pressure. (By courtesy of Capt. Geoffrey Marshall, R. A. M. C.)
in chest operations, maintaining the lung flabbily in the chest against the chestwall. or protruding out of the opening in the chest wall, as may be required.
In the surgery of the front area its quick action, its protective effect, the fact that it caused neither bronchitis, pneumonia nor nephritis, and that the patients recovered quickly so that they could eat and drink and travel soon after operation, and required less nursing care--all made nitrous oxide-oxygen the anesthetic of choice not only for routine operations, revising wounds, opening abscesses, etc., but especially for painful dressings, as it could be used repeatedly without harm. In the case of one patient in civil practice, Gwathmey
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mey has give nitrous oxide-oxygen 118 times; neither tolerance nor dread was established.10
Nitrous oxide, like ether and chloroform, must be pure. The apparatus for its administration must be capable of delivering any desired pressure and mixture of nitrous oxide and oxygen. The induction of anesthesia must be gradual, not too rapid; and respiration must be established and maintained at an even rate. The patient must be kept pink throughout the anesthesia. The pink patient can not die. If complete anesthesia can not be sured, as in alcoholics, and the patient kep pink, or if anesthesia is attained, but sufficient relaxation can not be secured and the patient kept pink by nitrous oxide-oxygen alone, then sufficient either must be added.
As for the technique of its administration, the following points may be noted: (1) In long operations, the fixation of the anesthetic mask with a towel fastened with forceps relieves the fatigue of holding the mask. (2) If induction is slow or difficult, a few whiffs of ether help to smooth out the respiration. (3) In abdominal cases local anesthesia is useful, and during exploration ether should be added. (4) Young, robust patients are most difficult subjects-the weaker the patient the easier the anesthesia. (5) In acute hemorrhage, the absence of pink color may make it more difficult to appreciate the depth of anesthesia so that the respiration must be closely watched. (6) Because nitrous oxide-oxygen anesthesia is more difficult to give, costs more, and requires more expensive apparatus than ether, this anesthetic seems less satisfactory to the operator; but because its protection is so great, its inhalation so pleasant, its after effects so slight, it must be regarded as strictly the patient's anesthetic.
SPINAL ANESTHESIA
Marshall's 9 observations have shown that one of the immediate effects of spinal anesthesia is the fall in blood pressure (Chart III). This has been conclusively shown in laboratory experiments on animals. Marshall has shown that the fall in blood pressure is most severe in the patient whose blood is dilute--his hemoglobin low--the patient most in need of the protection of nerve blocking. In both laboratory and clinic it has been shown that no amount of trauma upon an area physiologically severed from the brain by a local anesthetic, by blocking the spinal cord or the nerve trunks, or by local infiltration, can cause shock. In this manner, as far at least as trauma is concerned, a shockless operation may be performed, but the sights and the sounds of the operating room; the patient's knowledge that his flesh is being divided by a knife; that his blood vessels are being divided and tied; the sound of the saw that severs his bones; all these contribute to psychic shock. Moreover, in a rush period the delay of spinal anesthesia does injustice to patients waiting for operation when anaerobic contamination so promptly becomes gas gangrene. Spinal anesthesia is therefore of value in all but rush periods, provided that the consequent great fall in blood pressure may be prevented and that the psychic factor may be eliminated.
As has been shown in the laboratory and confirmed in the clinic. the transfusion of blood stabilizes the circulation to the following extent: In animals that are overtransfused so that the blood pressure rises higher than the normal
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blood pressure, the elasticity in the blood vessels provides a substitute for the peripheral resistance produced by the action of the vasomotor center and in consequence the blood pressure is independent of the nervous system and behaves as if it were controlled by a system of rubber tubes. After overtransfusion, therefore, spinal anesthesia, the destruction of the medulla and the cord, or even decapitation, cause no fall in the blood pressure, because the entire vascular system is not onlv filled but elastically distended with blood. This overdistention
CHART III.- Effect of special anesthesia or, pulse and blood pressure. (By courtesy of Capt. Geoffrey Marshall, R. A. M. C.)
lasts for one or two days. Therefore, in a case of profound exhaustion, if an ordinary transfusion of blood be given first, then spinal anesthesia may cause no serious fill in blood pressure. The other damaging factor, the physic factor, may be largely overcome by morphine, but still better by nitrous oxide analgesia, by very light nitrous oxide-oxygen anesthesia, or by light partial ether anesthesia-just enough anesthesia to eliminate psychic appreciation of the operation, room and the operation itself.
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Cabot made a special investigation of the value of spinal anesthesia in thigh amputations, regarding which he makes the following statement:
The mortality of thigh amputations for shell wounds under chloroform or ether anes-thesia was uniformly close to 40 percent in a series of somewhat over 100 cases, this during the battles on the Somme and the early fighting in 1917, particularly at Vimy Ridge. As a result of this experience, I gave orders that all thigh amputations should be done under spinal anesthesia and detailed an officer to handle the anesthetic. In 50 consecutive cases under this technic the mortality was just under 25 per cent. At the end of this series we stopped, on account of press of work, keeping any special records, and, therefore, the observation is only on a small scale, but seems to me of definite value. We had no opportunity of comparing the effects of ether and chloroform with nitrous oxide. It is my own opinion that nitrous oxide would have made a better showing than ether or chloroform.
One of the strongest advocates of spinal anesthesia was Desplas, who summarized its advantages as follows: 12
(1) No special anesthetist is needed. (2) Under spinal anesthesia any special treatment necessitated by the shocked condition of the patient may be easily given. (3) The possibility of pulmonary, renal, or hepatic complications such as result from general anesthesia are excluded. (4) There is no postoperative vomiting. (5) By spinal anesthesia complete relaxation of the muscles is obtained as under no other anesthesia. This condition is especially helpful in: (a) Extensive laparotomies, as the intestinal mass has no tendency to protrude and shock due to malaxation is thus, ipso facto, almost nonexistant. (b) Operations for extensive shattering of the lower members.
Desplas added that patients who have experienced both methods prefer spinal anesthesia.
As was emphasized by Rocher,13 spinal anesthesia was of especial value incases in which lesions in the air passages rendered inhalation anesthesia inadvisable, and also when the nature of the wound would require the maintenance of the prone position.
LOCAL ANESTHESIA
In the exigencies of war surgery, especially in rush periods at the front when apparatus for the administration of nitrous oxide-oxygen may not be available and the prolonged periods of induction and of recovery from ether or chloroform are not feasible, increased reliance must be placed upon regional or local anesthesia in combination with morphine. For the excision of contused tissues, for the removal of debris, for probing in soft tissues for missiles, for the amputation of fingers, for the repair of scalp wounds, local anesthesia may in many instances be preferable to the general anesthetic even when the latter is available; and, as indicated above in the cited conclusions of the Interallied Surgical Conference,2 local anesthesia is the anesthetic method of choice for the repair of cerebral wounds. Certainly these operations can be accomplished under local anesthesia with a minimum expenditure of time as well as with minimum discomfort to the patient. It should be borne in mind, however, that local anesthesia may decrease the resistance of tissues which are already contaminated.
ANALGESIA
In certain cases either the time factor or the exhaustion of the patient may make it advisable not to carry the anesthetic beyond the stage of analgesia. The former factor may be dominant in cases not suitable for the employment of
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a local anesthetic, as when vascular regions important organs are involved or wide retraction is required, or the second factor may be dominant in cases in which exhaustion from exposure, from hemorrhage, or infection has so impaired the internal respiration of the cells as to make the induction of complete surgical anesthesia menacing. An attempt to meet this problem wits made by Gwathmev and Karsner,14 who made a study of the effects of the oral administration of various combinations of anesthetics, in particular of ether and chloroform combined with liquid petrolatum. In addition to experiments on animals a clinical application of this method was made on a group of soldiers in Base Hospital No. U. S. A. in service at No. 9 General Hospital B. E. F., and later by Captain Gwathmey at a casualty clearing station.
The safest method of analgesia is that induced by nitrous oxide-oxygen; when this is not available, the combination of morphine with local anesthesia or with nerve blocking provides the maximum protection.
ADJUVANT MEDICATION
MORPHINE
Morphine has possibilities for good and for evil which are not yet fully appreciated. Laboratory researches have confirmed what clinicians have experienced, viz, that morphine diminishes shock, prolongs life in precarious situations, such as deep hemorrhage, shock, infection; that, under morphine, patients require less food and the temperature and pulse in infections are materially controlled; that under such circumstances the morphine habit is not formed. Clinical experience shows, further, that morphine does harm when patients are cyanosed. Researches have shown that when large doses of morphine are given to animals under deep anesthesia or in acute cyanosed exhaustion from intense exertion, they are deprived of the power to overcome the cyanosis, i. e., the acute acidosis. Therefore, cyanosed patients should never have morphine.
While morphine never causes a habit when given in these extremely critical states, it easily establishes a habit when given in cases of psychic distress, in worry, insomnia, etc. There is opportunity for wide discrimination in its use-in one case, none should be given; in another case, light doses may be beneficial; in other cases massive doses are most useful. When the way is clear so that massive doses of morphine may be given safely, it is a most potent agent. In the surgery of war it was of paramount value when used as an adjuvant to general or local anesthesia.
MAGNESIUM SALTS
In the laboratory it has been found that to a limited extent the intravenous administration of magnesium salts is apparently a strong agent in promoting intracellular restoration. Intravenous infusions of magnesium salts lower the respiratory rate, and induce a state resembling sleep. This magnesium "sleep"lasts approximately two hours. The good effects of the infusion are well sustained. Not only are the clinical results apparently good, but a study of the effect upon the cytologic changes in the liver cells in exhaustion shows a diminution of the edema, not as marked but similar to that resulting from normal
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sleep. It is possible, therefore, that the magnesium salts partially exert the effect of sleep in aiding cellular repair; hut the magnesium salts alone, in good dosage, are cardiac depressants. Their use is under observation, their value not established.
METHODS IN SPECIAL GROUPS OF CASES
As stated at the beginning of this chapter, in discussing the anesthetic method of choice in special groups of cases it is impossible entirely to separate the anesthetic from the other factors of the operative management. It is obvious that in the case of the wounded soldier, as of the civilian patient, the management of the operation implies the closest cooperation between the surgeon and the anesthetist. For this reason, in the following summary the operative factors which war experience demonstrated to be of primary importance, are included with the discussion of the anesthetic method of choice in each case.
SHOCK AND EXHAUSTION
Among the memoranda issued from the Division of Laboratories, A. E. F. those relating to traumatic shock and hemorrhage contain the following statements regarding anesthesia.15
Clinical observations have shown that after the body has been damaged by a shock Blood pressure there is great sensitiveness to ether and chloroform anesthesia. Experimental tests have proved that a degree of anesthesia which abolishes in a shocked animal the simple reflexes may cause the arterial pressures to fall rapidly 20 mm. of mercury or more. In a series of human cases the fall of pressure during operation averaged 30 mm. of mercury--a disastrous drop in view of the already existing low pressure. There arc two ways of avoiding this harmful change--by use of nitrous oxide and oxygen as an anesthetic and by sustaining the pressure if ether is employed.
Clinical and experimental observations have demonstrated that if anesthesia with Nitrous oxide and oxygen is properly produced a shock blood pressure need not be lowered at all during the course of operation. Preoperative administration of morphine should bet followed by expert use of nitrous oxide and oxygen in the ratio of not more than 3 parts nitrous oxide to 1 part oxygen. A higher ratio may cause as great a fall of pressure as is produced by ether. Deep anesthesia and cyanosis are to be avoided at all times. The surgeon must adjust himself to this light anesthesia, and its consequent absence of complete relaxation, by patience and gentleness and by a larger operative incision when necessary.
If nitrous oxide and oxygen are not available, ether given by the drop or vapor method should be employed. As soon as the anesthetic is started, however, a blood transfusion or an infusion of gum-salt solution should be started and allowed to continue slowly. The head of arterial pressure is thus maintained and may even be raised during the period when it otherwise would be much lowered.
Chloroform and ethyl chloride, which are even more depressant to the circulation than ether, are to be employed only when no other means of producing anesthesia is obtainable. The foregoing directions are approved by the Chief Consultant in Surgery of the American Expeditionary Forces.
In brief it may be stated that for the soldier in shock or exhaustion, whatever the nature of the wound, the primary requisites are physiologic rest, fluids by every possible route-by mouth, by hypodermoclysis, by intravenous Injections-elevation of the foot of the bed; morphine if there is no cyanosis; transfusion of blood; quick, deft, light operation. The anesthetic of choice, as has been sufficiently indicated above, is nitrous oxide-oxygen analgesia combined if possible with local or regional anesthesia.
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ABDOMINAL OPERATIONS
If nitrous oxide-oxygen is used and it is the anesthetic of choice, regional infiltration with novocain should be employed also to promote relaxation of the abdominal muscles. If relaxation is not complete then ether should be added but only during the exploration.
If ether is employed Gwathmey's warmed vapor technique, combined with local infiltration, is the best method of induction.16
As Marshall has emphasized, the patient should be turned from side to side as little as possible during operation. The abdomen should be kept open the
CHART IV.- Comparative effects of ether and or nitrous oxide in operations for the repair of extensive abdominal wounds. Note the greater extent of the trauma in the second case, which received nitrous oxide. (By courtesy of Capt. (Goeffrey Marshall, R. A. M. C.
least possible, length of time. Manipulations and exposure of the viscera should be reduced to a minimum; therefore, an ample incision should be made.9 If the patient is in deep shock, a transfusion of blood should be given at the beginning, and again at the close of the operation.
OPERATIONS ON THE CHEST
An extensive research was carried out by Gwathmey and his associates at the Central Medical Department Laboratory, A. E. F., at Dijons, France, for the purpose of determining the anesthetic method of choice.17 The findings in this study were in accord with the clinical experience of Marshall, of the
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writer, and of others, that nitrous oxide-oxygen under positive pressure is the method of choice. The following statements regarding the anesthesia in chest surgery were made by Lockwood: 18
Paravertebral anesthesia is administered two or three spaces above and below the wound. A local infiltration at some distance from the wound is employed.
Novocain 5 percent and potassium sulphate 0.25 percent in normal saline, prepared fresh and repeatedly autoclaved is injected with a Gray's syringe (10 mms. of adrenalin per ounce are added just before use). Gas and oxygen should be available for administration while the hand is inside the chest or when the patient is restless.
The most serious cases may be operated on with a light nitrous oxide analgesia. Local anesthesia combined with gas and oxygen is the best means of preventing shock in extended operations. Neither ether nor chloroform should be used in chest surgery.
An official report on intrathoracic surgery contains the following section on anesthesia:19
A simple method of giving nitrous oxide and oxygen, utilizing tank pressure, to secure needed degree of inflation, was devised by Captain Gwathmey. A full preoperative dose of morphine made possible the induction of deep analgesia, without increasing the nitrous oxide and oxygen rates above 3 to 1, which Lieutenant Colonel Cannon s experiments had proved to be the limit of safety in the presence of shock. Lieutenant Cattell's observations had indicated that morphine thus given had value as a prophylactic agent against oncoming shock and therapeutic value when given early in the presence of shock. No untoward result from depression of the respiratory centre was noted.
Animal experiments showed clearly that administering anesthesia under tension, particularly when the chest was opened, was dangerous if the gas or ether was given in increased concentration. It also demonstrated that thoracotomy with all incidental manipulations, such as dislocation and operation upon lungs, should be performed under the primary stage of anesthesia. Manometric observations showed that when the pressure present in the mixing bag reached 8-16 mm. Hg. it sufficed to distend the lungs completely; that degree of pressure is present when the bag fluctuated little during inspiration. Since this degree of tension in the bag produced an intrapulmonary pressure that was well within the limits of safety for dogs, the manometer was not deemed a necessary adjunct for human use.
A safe sequence in practice was found to be as follows: After the effect of the preoperative hypodermic of morphine was present, administrations of pure oxygen under no tension were started. Then very gradually the pressure was increased, and the administration of nitrous oxide started. Rapid induction of the anesthesia was undesirable. Avoidance of excitation and the producing of gradually increasing inflation were essential. During the operation the proportions of the gas-oxygen mixture and the pressure transmitted to the trachea were varied to meet conditions . After the parietal pleura was closed the amount of nitrous oxide was gradually reduced; last of all, oxygen under pressure was continued until the patient was conscious.
The American Red Cross nitrous oxide apparatus, perfected by Captain Gwathmey and adopted by the Army, fulfilled every requirement. This apparatus provides a mask that can be rendered relatively air-tight by close approximation to the face, an escape valve, a mixing bag close to the inhaler, and a rough gauge for estimating the proportion of the gases.
Intrapulmonary pressure was raise by increasing the rapidity of the flow of gases from the tank and by increasing the pressure upon the face piece. It was lowered by decreasing the rate of flow of the gases or by releasing the valve or decreasing the pressure which held the face piece in place. Thus, any degree of desirable inflation or deflation was promptly available to meet operative requirements. In general the degree of pressure utilized was that test suited to the animal or man under operation.
This method gives all practical requirements for intrathoracic surgery without necessitating deep anesthesia for the introduction of intratracheal or endopharyngeal tubes. Moreover, its safety and ease of control has removed the chief obstacle to a wider application of surgical therapy.
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On the basis of his large experience in France and at the Walter Reed Hospital since the war, Keller makes the following statement: 20
Nitrous oxide is, in my opinion, the anesthetic of choice in war-time general surgery and its general use in all formations from front to rear during the late war was limited only by lack of trained anesthetists and difficulty of transportation to some front line formations. Its use is also somewhat limited for mobile warfare such as during a rapid advance.
In chronic chest surgery nitrous oxide is absolutely the inhalation anesthetic of choice, especially when combined with the Crile novocain block or paravertebral block, which enables the operator to do chest work without passing the stage of analgesia.
Nitrous oxide used in the above manner has lowered the operative mortality in the chronic thoracic surgical derelicts to a degree not attainable with other inhalation anesthetics.
It is of interest to note also that in the section on chest surgery in a questionnaire sent by the Research Committee of the American Red Cross to base hospital staffs in France the following preferences as to the anesthetic were expressed: 21 Local anesthesia if possible was recommended by all. For general anesthesia, the stated first choice was as follows: Gas oxygen, 18; ether, 9; warm ether, 3; chloroform, 2.
To summarize, in intrathoracic surgery, if there is cyanosis, oxygen should be given under pressure with enough nitrous oxide for analgesia until the gray-blue color or the ordinary cyanosis gives place to a pink color. This will usually require from 10 to 15 minutes. When the pink color has been restored the anesthetic may be deepened as required. With the gas and oxygen apparatus the lungs can be inflated under positive pressure, cyanosis overcome and anesthesia maintained; and under high pressure both anesthesia and sufficient lung ventilation can be maintained even when both sides of the thorax are widely and simultaneously opened.
An adequate exposure should be made. Resecting a rib is better than working in a cramped space. The lungs and heart and pleura should be handled precisely and gently. The patient should be moved as little as possible, the chest closed air-tight. Oxygen should be given under pressure at intervals during the first 24 hours, as the condition of the patient may indicate.
OPERATIONS ON THE EXTREMITIES
Nitrous oxide-oxygen is the anesthetic of choice, but if it is not available then low spinal anesthesia by Cabot's method may be given, but in such a case it is necessary to be prepared to give a blood transfusion to overcome the low blood pressure which will be caused by the anesthetic.
When dealing with fractures under anesthesia, no less than without anesthesia, the limb should be orientated and handled so skillfully that little or no crepitus will be felt. In amputations the nerve trunks should be divided as lightly as possible and the limb handled as little as possible. In grave shock, if no nitrous oxide is available, low spinal anesthesia by Cabot's method may be used and preparations made to give blood transfusions to overcome the lowered blood pressure caused by the anesthetic. Large wounds should be covered and protected as much as possible. (Chart V.) (See also Chart II.)
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GASSED CASES
Oxygen under pressure should be given first, with just sufficient nitrous oxide to eliminate the worry due to the mask and to the oxygen inhalation. After the pink color is restored, light surgical anesthesia may be induced. The operation should he short and deft. As required, oxygen under pressure should be given during the post-operative period. In these cases if nitrous oxide is not available, local, regional, or spinal anesthesia should be employed rather than general anesthesia.
CHART V. – Comparative effects of either and nitrous oxide in thigh amputations as indicated by the pulse and blood pressure. (By courtesy of Capt. Geoffrey Marshall, R.A.M.C.)
In cases of phosgene poisoning it should be borne in mind that phosgene poisons by reason of its interference with the passage of oxygen through the walls of the air vesicles, thus producing anoxemia. Cases of phosgene poisoning, as is indicated by the rapid respiration, increased pulse rate, cyanosis, loss of mental and muscular power, sweating, etc., are in a state of acute acidosis--the same end effect as is produced by prolonged inhalation anesthesia, by exertion, fever, emotion, shock, exhaustion, etc. Therefore, since the inhalation anesthetics themselves cause acidosis, their administration adds one acidosis to another; i. e., the acidosis of anesthesia intensifies the acidosis of phosgene asphyxia. Surgical shock also produces a state of acidosis. The
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acidosis of the surgical operation, therefore, if added to the acidosis of the phosgene and the acidosis of the anesthetic may kill the patient.
Therefore, when an operation is required in a case of phosgene poisoning, it should be performed under local, regional, or spinal anesthesia, the patient meanwhile being kept pink by oxygen under pressure by means of the positive pressure mask of a nitrous oxide apparatus or a Haldane apparatus. If there is a phase of operation that can not be controlled by local or regional or spinal anesthesia, then one should give oxygen under pressure until the patient has a pink color, then switch to nitrous oxide for the briefest time required for the operative move, then switch back again to oxygen under pressure.
OPERATIONS IN THE PRESENCE OF ACUTE INFECTIONS
While narcotization with morphine is of value in all cases excepting in the presence of cyanosis, in the acute infections, as has been proved by experiment and demonstrated repeatedly in civilian and war hospitals, morphine is of paramount value. In such cases, therefore, the first requisite is deep narcotization with morphine, and if time permits the subcutaneous infusion of 1,000 c.c. of normal saline solution before operation. Nitrous oxide-oxygen analgesia should be used, the stage of full anesthesia being induced only as the exigencies of the operation demand. The morphine narcotization and saline infusions should be continued until the patient is safe.
CONSENSUS OF OPINION AMONG BASE HOSPITAL STAFFS
The questionnaire already cited contained, as would be supposed, special sections regarding the value of different types of anesthetics. For details in connection therewith consult the appendix of this volume.
LIMITATIONS OF DIFFERENT TYPES OF ANESTHESIA
The problems presented by anesthesia in war surgery, as in civilian surgery, are in effect problems of limitations. Therefore, since in the exigencies of military surgery the anesthetic method of choice may not always be available, it is peculiarly essential that the limitations of each type of anesthetic be kept clearly in mind.
SPINAL ANESTHESIA
In the low blood pressure of acute shock or hemorrhage the additional fall due to spinal anesthesia as a result of the interruption of so large an area of vasomotor nerves may cause dangerous, even fatal collapse. This may be pre-vented by blood transfusion. The psychic factor may be both distressing and damaging, but may be eliminated by very light ether anesthesia. Occasionally spinal anesthesia is incomplete. Such a failure must be met by a general anesthetic.
NITROUS OXIDE
In abdominal operations muscular relaxation may not be complete under nitrous oxide anesthesia. The condition should be met by regional anesthesia of the abdominal wall and by light handling.
Nitrous oxide is a light anesthetic, demanding of the surgeon a light deft operative technique. Nitrous oxide must be given only by experts; it is dangerous in inexpert hands.
183
ETHER
Ether tends to cause bronchopneunonia, especially in abdomninal operations during the winter. It diminishes, even temporarily abolishes, phagocytosis, and is therefore unsuitable in infections. There is a tendency to a fall in blood pressure after operation; hence it is unsuitable in shock. Ether causes a rather large diminution in the reserve alkalinity of the blood.
THE ANESTHETIST
If, as has been demonstrated, nitrous oxide-oxygen is the anesthetic method of choice in military surgery, then it is essential that corps of anesthetists especially trained for its administration should be available. Safest of anesthetics in expert hands, nitrous oxide is the most unsafe in the hands of the inexpert. Since in military surgery the majority of patients are already grave risks on account of exposure, exhasustion, and infection, it is peculiarly necessary that the anesthesia should be handled by trained hands.
REFERENCES
(1) Burlingame, C. C. Lt. Col.: Military History of the American Red Cross in France, 135. On file, Historical Division, S. G. O.
(2) Conclusions adoptées par la Conference Chirurgicale Interalliée, 1st Session, 15th and 16th March, 1917. Archives de médecine et de pharmacie militaires, Paris, 1917 1xvii, 531.
(3) Bid., 2d Session, 14th to l9th May, 1917, lxviii, 451.
(4) Letter from Major Harry L. Gilchrist, M. C., to The Adjutant General, May 8, 1917. Subject: Departure of Base Hospital No. 4. On file, Record Room, S. G. O., 159444 (Old Files).
(5) Burlingame, op. cit., 137.
(6) Red Cross Reports on Nitrous Oxide and Oxygen Service. On file, Historical Division, S. G. O.
(7) Cannon, W. B.: Acidosis in Case of Shock, Hemorrhage, and Gas Infection. Journal of the American Medical Association, Chicago, 1918, lxx, No. 8, 531.
(8) Cattell, McKeen. Studies in Experimental Traumatic Shock. VI. The Action of Ether on the Circulation in Traumatic Shock. Archives of Surgery, Chicago, 1923, vi, No. 1, 41.
(9) Marshall, Geoffrey. Anesthetics at a Casualty Clearing Station. American Journal of Surgery, Anesthesia Supplement, New York, 1918, xxxii, No. 4, 61.
(10) Gwathmey, James T.: Personal communication.
(11) Cabot, Hugh: Personal communication.
(12) Desplas: Spinal Anesthesia. Medical Bulletin, Red Cross Research Society Reports. Paris, 1918, No. 6, 447.
13) Roclher, H. L.: La rachi-anesthésie en chirurgie de guerre. Journal de médecine de Bordeaux, 1919, xc, ni.s., No. 1, 5.
(14) Gwathmey, James T. and Karsner, H. T.,: General Analgesia by Oral Administration. British Medical Journal, London, March 2, 1918, i, 254.
(15) Surgery in Relation to Shock. War Medicine, Paris, 1918, ii, No. 5, 785.
(16) Gwathmey, James T.: Anesthesia. The Macmillan Company, New York, 1924. 153.
(17) Ibid., 692.
(18) Lockwood, A. L. Early Operative Treatment in Chest Surgery. War Medicine, Paris, 1918, ii, No. 1, 7.184
(19) Official Report from Laboratory of Surgical Research, Central Medical Department Laboratory, A. E. F., to Brig. Gen. J. M. T. Finney, M. C., Chief Consultant in Surgery, A. E. F. Subject: Intrathoracic Surgery (Anesthesia). War Medicine Paris, 1919, ii, No. 6, 1008.
(20) Keller, Win. L., Lt. Col., M. C.: Personal communication.
(21) Compilation of Responses by Base Hospital Staffs to Questionnaire sent out by Research Committee. Questionnaire prepared by Brigadier General J. M. T. Finney and Colonel G. W. Crile; Compilation of Responses made by Major T. W. Burnett, M. C. War Medicine, Paris, 1919, ii, No. 7, 1281.
