CHAPTER XII
Anesthesia
George E. Donaghy, M. D., Ernest A. Doud, M. D.,
Werner F. Hoeflich, M. D., and Charles W. Westerfield, M. D.
For the most part, anesthesia in the 3,154 abdominal injuriestreated by the teams of the 2d Auxiliary Surgical Group during 1944 and 1945 wasadministered by physicians. Many of the 45 anesthetists attached to the grouphad received formal training. Others had had limitedtraining and experience, but some had had neither training nor experience.Ideally, because soldiers with abdominal injuries may present incredibledifficulties in anesthetic management, anesthetists who care for them shouldpossess a good general medical background, an understanding of the principles ofmanagement of the physiologic disturbances following abdominal andthoracoabdominal wounds, and proficiency in the diagnosis and treatment of shockand in the recognition and care of complications. For obvious reasons, thisideal was frequently not achieved.
STATUS OF CASUALTIES
Detailed information concerning the status of casualties on their arrival atthe field hospital after triage at the division clearing station is set forthelsewhere (p. 124), but certain of these facts should be reiterated here; theyfurnish the background for the discussion of anesthesia in abdominal injuries inwartime.
The majority (approximately 90 percent) of the casualtieswith abdominal wounds treated in the field hospitals by surgeons of the 2dAuxiliary Surgical Group were nontransportable; that is, they required immediateoperation. The timelag from wounding until hospitalization ranged from between15 and 30 minutes to between 30 and 40 hours. Exclusive of the cases in whichthe abdominal wall was penetrated without visceral injury, the injuries variedfrom a small wound of a single viscus to penetrating and perforating wounds ofseveral organs. More than a quarter of the patients (26.6 percent) hadthoracoabdominal injuries. All types of associated (extra-abdominal) injurieswere present in all conceivable sites. The physical status of many of thecasualties was only fair or actually poor. Some degree of shock was present inmost cases; frequently it was extremely severe. In a representative sample of957 cases, 14.6 percent of the patients had systolic blood-pressure readingsfrom 0 to 40 mm. Hg, 12.7 percent from 41 to 70 mm. Hg, 26.1 percent from 71 to100 mm. Hg, and 46.6 percent from 101 to 120 mm. Hg. Often there had beenperiods, sometimes long periods, of fatigue, exposure, and dietary limitationsbefore the injuries had occurred.
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Pulmonary blast injuries deserve special mention. Thesmall number in this series suggests that only the most severe were put onrecord and that the majority, because they were minimal, were either notrecognized or not entered on the charts. The gravity of this particular problemnaturally varied with the degree of injury. Casualties who had sustained severebilateral injuries furnished the anesthetists with many special problems. It wasa real achievement to anesthetize a patient with this type of injury withoutlosing him on the table from pulmonary edema. No form of anesthesia, least ofall ether, was well tolerated, and it was always difficult to maintain anadequate airway during operation and afterward.
AGENTS AND METHODS
Although a wide variety of anesthetic agents was available inthe Mediterranean theater, anesthesia, for practical reasons, was accomplishedin more than 90 percent of all cases with ether (table 23). The agents suppliedincluded, in addition to ether, chloroform, ethyl chloride, nitrous oxide,Pentothal, procaine, Pontocaine, cocaine, and oxygen. Methods employed includedthe open-drop method; the closed-circle flow absorption method, with Heidbrinkand McKesson machines; the closed to-and-fro absorption method, with the Beechermodel machine; intravenous injection; intratracheal injection; local, regional,and field block; and topical application.
TABLE 23.-Distribution of anestheticagents in 3,154 abdominal injuries
Anesthetic agents | 1944 | 1945 | Total | |||
Cases | Proportion | Cases | Proportion | Cases | Proportion | |
|
| Percent |
| Percent |
| Percent |
Nitrous oxide-oxygen-ether | 1,306 | 54.81 | 642 | 83.3 | 1,948 | 61.77 |
Ether | 752 | 31.56 | 48 | 6.2 | 800 | 25.37 |
Ethyl chloride-ether | 224 | 9.40 | 57 | 7.4 | 281 | 8.91 |
Pentothal-ether | 49 | 2.06 | 1 | .1 | 50 | 1.59 |
Chloroform-ether | 1 | .04 | 0 | 0 | 1 | .03 |
Nitrous oxide-oxygen-ether-Pentothal | 1 | .04 | 0 | 0 | 1 | .03 |
Ether-procaine | 3 | .13 | 0 | 0 | 3 | .09 |
Procaine (local) | 5 | .21 | 1 | .1 | 6 | .19 |
Procaine (spinal) | 2 | .08 | 0 | 0 | 2 | .06 |
Procaine-Pentothal (spinal) | 1 | .04 | 0 | 0 | 1 | .03 |
Nitrous oxide-oxygen1 | 1 | .04 | 0 | 0 | 1 | .03 |
Pentothal2 | 1 | .04 | 0 | 0 | 1 | .03 |
Oxygen3 | 1 | .04 | 0 | 0 | 1 | .03 |
Not stated | 36 | 1.51 | 22 | 2.9 | 58 | 1.84 |
| 2,383 | 100.00 | 771 | 100.0 | 3,154 | 100.00 |
1Patient died from aspiration of gastric contents following vomiting during induction of anesthesia.
2Simple debridement of thoracoabdominal wound of entrance.
3Patient unconscious and moribund.
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Routine Agents and Method
The 2d Auxiliary Surgical Group found soon after it had become operationalthat the most satisfactory anesthesia for severely wounded battle casualties wassecured by (1) induction by nitrous oxide-oxygen and (2) maintenance byether-oxygen in a closed carbon dioxide absorption system. This method wasadopted and came into general use because of its ready availability, itssimplicity of administration, its satisfactory tolerance by patients, and itswide margin of safety. The possible toxic effects of ether on the heart, liver,and kidneys were fully realized, but simplicity of administration and the widemargin of safety were considerations of greater importance in view of the factthat, as already mentioned, the anesthetics were administered by some 45anesthetists of widely varying training, experience, capabilities, and judgment.
Although ether, combined with oxygen and following induction with nitrousoxide, was the most popular anesthetic agent in this series, its use by theopen-drop method was considerably less extensive than might have been expected(table 24). This method was used in 12.5 percent of all cases treated in 1944,when anesthesia machines were in limited supply, but in only 2.7 percent of theoperations in 1945, when equipment had become widely available.
Closed anesthesia had many desirable features for military surgery, includingconservation of body heat and moisture, the maintenance of a high oxygen contentand the control of carbon dioxide content in the blood, ease of attaining andmaintaining desired levels of anesthesia, and control of respiration andmaintenance of positive pressure when these special conditions had to be met.The necessity for an anesthesia in which these objectives could be accomplishedwas naturally magnified in casualties in critical condition. There was thereforean increasing use of the closed technique as the war progressed (table 24).
The endotracheal technique also had an extensive andincreasing use, which in most cases was essential rather than preferential. Byit, a patent airway was provided and maintained, no matter what the position ofthe patient.
TABLE 24.-Distribution of techniques of administration of anesthesia in 3,154 abdominal injuries
Method | 1944 | 1945 | Total | |||
Cases | Proportion | Cases | Proportion | Cases | Proportion | |
|
| Percent |
| Percent |
| Percent |
| Inhalation: |
|
|
|
|
|
|
| Closed | 2,028 | 85.1 | 727 | 94.3 | 2,755 | 87.4 |
| Open | 298 | 12.5 | 21 | 2.7 | 319 | 10.1 |
| Semiopen | 7 | .3 | 0 | 0 | 7 | .2 |
| Others | 14 | .6 | 1 | .1 | 15 | .5 |
| Not stated | 36 | 1.5 | 22 | 2.9 | 58 | 1.8 |
| 2,383 | 100.0 | 771 | 100.0 | 3,154 | 100.0 |
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The anesthetist, as a result, had sufficient freedom of actionto aspirate blood and accumulated secretions easily via the tube and tosupervise or administer transfusions when they were required. The endotrachealtechnique facilitated the control of respiration by positive pressure andassisted in the attainment of desired levels of anesthesia, while the increasedsmoothness of respiration achieved with a tube in situ simplified the task ofthe surgeon working in the abdominal cavity. The endotracheal technique wasemployed in 1944 in 89.8 percent of the 2,108 cases in which a definitestatement was made on the matter. The fact that in 1945 it was employed in everyone of the 749 cases in which technique was recorded is an indication of theincreased appreciation by the surgeons of the group of its numerous advantages.
Other Agents and Methods
Chloroform.-Why chloroform wasused for induction in one case in this series is not clear. The dangers of thisagent were so well known to both the surgeons and the anesthetists of the groupthat there was no temptation to employ it to anesthetize casualties with suchinjuries as these men had sustained.
Pentothal.-In 1944, Pentothalwas used 49 times as an induction agent preceding ether anesthesia and once asan adjunct to spinal analgesia (table 23). In this same year, it was used in oneinstance as the sole anesthetic agent, for simple debridement of athoracoabdominal wound of entrance. In 1945, it was used only once, as theinduction agent.
The extremely limited use of Pentothal by the surgeons of the2d Auxiliary Surgical Group has significant implications. This anesthetic agentwas reported to have been used extensively elsewhere, in some areas in 95percent of all cases, and it may be that the discrepancy between this usage andthe usage of the group can be explained by the type of cases handled, theproblem of supply, the echelon at which surgery was done, or a combination ofthese factors. In the opinion of the group surgeons, all the well-recognizedcontraindications to Pentothal were present in most of the abdominal injurieswhich came under their observation. A large proportion of the patients were inshock. Hemorrhage before hospitalization was often serious, and further loss ofblood could be expected during operation. Anoxia of varying degrees resultedfrom hemorrhage and shock, and the accumulation of secretions in thetracheobronchial tree, hemothorax and pneumothorax, painful respiration, andother derangements of cardiorespiratory physiology furnished other problems. Thesurgery required was frequently formidable and time consuming. Muscularrelaxation was essential during operation, particularly while exploration andclosure were being carried out. Endotracheal intubation, which was almostuniversally employed, was difficult to accomplish under Pentothal anesthesia,because of irritability of the larynx and poor relaxation of the muscles of thejaw. The status of the patient thus militated against the use of Pentothal,while the criteria of desirable anesthesia for this type of injury weredifficult or impossible to attain when it was used. Finally, serious reactionsoften occurred
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when the tube was inserted, and a secondreaction was likely to occur when the catheter was moved as the patient wasshifted on the operating table or when his head was turned.
Nitrous oxide-Nitrous oxide,although it was used routinely as an induction agent, was never used as the soleanesthetic agent (table 23). It was always employed with oxygen concentrationsof at least 20 percent, and many anesthetists preferred concentrations of 30percent or more. Concentrations of 60 to 75 percent were frequently used, and nodifficulties were experienced in the brief periods in which they were necessary.Such concentrations, however, are not compatible with a satisfactory level ofanesthesia, and nitrous oxide would therefore have been impractical as theprimary anesthetic for patients who, like these, were in shock, who had seriousand often multiple wounds, who required prolonged major surgical procedures, andwho had to be provided with the highest possible concentrations of oxygen tocompensate for the loss of their own oxygen-carrying powers.
Ethyl chloride-Ethyl chloride was used as aninduction agent in a large number of cases (table 23) and was satisfactory forthis purpose when it was administered cautiously. It was not ordinarily used inpatients who presented poor risks, and it was never used as the sole anestheticagent.
Spinal analgesia-Spinal analgesia was not regarded as suitable forfrontline military surgery for a number of reasons, including the following: Thelength, as well as the variability, of the time necessary for surgery; theunstable cardiovascular balance of casualties in shock, who had sustained largeblood losses; the frequency of associated wounds in areas which cannot beaffected by this anesthetic method; and the undesirability of full consciousnessin an apprehensive casualty not long removed from the battlefield. Spinalanalgesia was used only 3 times in the 3,154 cases (table 23). In each instance,the patient was in excellent condition and there was no doubt thatintra-abdominal injury was minimal.
Procaine.-Procaine was occasionally used to secure regional or fieldblock analgesia (table 23), each time in combination with a light inhalationanesthetic. In retrospect, the combined method seems to have excellentpotentialities in military surgery, and it is regrettable that it was not givena more adequate test.
Cocaine.-Cocaine was used according to the ordinary indications forbronchoscopy on conscious patients and, occasionally, to facilitate a difficultintubation.
PREOPERATIVE MANAGEMENT
When a field-hospital platoon was well organized and fully staffed, patientswith abdominal and thoracoabdominal injuries were placed in charge ofexperienced shock teams as soon as they were received from the clearing station.These ideal circumstances did not always exist. In the absence of a shock team,or when the flow of casualties was extremely heavy, both anesthetists andsurgeons worked in the resuscitation ward. It was therefore
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necessary, as already intimated, for the anesthetist to be familiar withshock therapy because emergencies might arise during which the fullresponsibility for resuscitation would fall upon him.
It was always desirable for the anesthetist to make a preliminary study ofthe patient before he received him in the operating room, but during rushperiods such contacts were not always possible. The anesthetist, however, alwaysdetermined the pre-anesthetic medication to be administered in the particularcase. As a rule, atropine gr. 1/100was given, in combination with morphine if that drug wasindicated (p. 76). Before operation, morphine was usually given by theintravenous route.
MANAGEMENT DURING OPERATION
The patient was kept in the shock ward until the anesthetic equipment was inorder and the instruments were set up for operation. Resuscitation therapy wasinterrupted as briefly as possible during his transfer to the operating room. Ifoxygen, for instance, was being administered, it was discontinued only duringthe actual interval of transportation by the litter carriers.
Induction was seldom difficult. Many of the wounded had gonewithout sleep for long periods and were completely exhausted, and those who werein shock, or who had been in shock, were, as usual, easy to anesthetize. Severeexcitement stages seldom occurred, in contrast to their relative frequency incivilian practice. This was surprising. It had been expected, if only because ofthe sounds of Allied and enemy artillery and the unavoidable noise and bustle ina busy surgical tent, that excitement would have been frequent and violent.
Anesthesia was maintained in the lightest possible planecompatible with the surgery required in a given case. Men in the condition ofthese casualties could not usually tolerate deep planes of anesthesia for morethan brief periods of time.
Two of the anesthetists in the group were authorized toemploy a preparation of curare, on a trial basis, as a supplementary anestheticagent, to facilitate intraperitoneal manipulations during periods of lightanesthesia.1 Included inthe 26 casualties in whom the method was used were 10 with thoracoabdominalwounds and 13 who had recently been in shock. All received nitrousoxide-oxygen-ether anesthesia by the closed endotracheal technique and weregiven curare in various dosages and at various times during the operation.
The immediate results of this method were excellent in allcases in which it was tested; there were no postoperative complications and nodeaths which could possibly be attributed to the use of curare. Abdominalrelaxation was entirely satisfactory in every instance, and ether anesthesiacould be maintained in the lower part of the first plane, which was thought tobe more desirable than the deeper levels ordinarily necessary in militarysurgery within the abdomen. Both anesthetists who conducted the trials withcurare stressed the importance of employing the endotracheal technique when itwas used.
1Doud, E. A.; and Shortz, G.: The Use of Curare for Abdominal Surgery in Seriously Injured Patients. Anesthesiology 7: 522-525, September 1946.
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The foot of the litter was frequently raised beforeanesthesia was induced, and many operations were performed with the patient inthe Trendelenburg position. All anesthetists commented on the fall in bloodpressure which occurred when the position was changed. The drop was most notablewhen patients were changed from the supine to the prone position, or vice versa,but alterations also occurred when they were turned on the side. This phenomenonwas interpreted as direct evidence of the instability of the vasomotor system inseverely wounded, anesthetized patients. Experience soon showed that unnecessarymovement of the patient on the operating table must be avoided, and that whenchanges of position were necessary, they must be accomplished slowly and gently,so that the decrease in tension would be minimized as far as possible. Ephedrine(gr. ?) was occasionally administered a few minutes before the position was tobe changed, in an attempt to produce a general vasoconstriction and increasedcardiac output and thus to sustain the blood-pressure level.
A clear airway was maintained at all times. Attention to thispoint was particularly necessary during the winter, when many of the woundedcame to operation with bronchitis and had large accumulations of thick mucoidmaterial. Attention has already been called to the increase in the number ofpatients handled under endotracheal anesthesia as the anesthetists gainedproficiency in this method.
In other respects, the management of patients during operation was also acontinuation of resuscitative measures. Pain was abolished by anesthesia.Reestablishment of normal metabolism was aided by the administration of oxygenin high concentrations. Restoration and maintenance of the blood volume wereaccomplished by transfusions. Solutions of dextrose and saline were used only tocombat dehydration. When there had been a decrease in the adequate circulatingblood volume, citrated blood in the necessary amounts was administered. Verylarge amounts (up to 6,500 cc.) were used in patients who had sustained injuriesto the major blood vessels. Stimulating drugs were seldom administered.
It is well recognized in civilian practice that the longerthe duration of an operation, and therefore of anesthesia, the more likely thepatient is to leave the operating table in poor condition and to presentpostoperative complications. The observation was equally valid in militarysurgery, but little could be done to alter the unfavorable circumstances. Indealing with seriously wounded men, especially when their wounds were multiple,there were few short cuts available to the surgeon by which the operating timecould be reduced. The anesthetist did all in his power to maintain a viablepatient, by the use of oxygen, Coramine (nikethamide), ephedrine, Adrenalin(epinephrine hydrochloride), transfusions (sometimes into every extremity),sternal transfusion, and artificial respiration, according to the indications.All that the surgeon could do was to work as quickly as he could in the light ofthe needs of the patient.
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Differences in techniques and in individual speed among thevarious surgeons of the group, as well as differences in injuries among thecasualties, resulted in wide variations in operating time. The average time wasbetween 2? and 3 hours, but the range was between 45 minutes and 6 hours. Theduration of anesthesia was always 10 to 15 minutes longer than the duration ofthe surgical procedure.
POSTOPERATIVE COMPLICATIONS OF ANESTHETIC ORIGIN
The postoperative care of the patient was the jointresponsibility of the anesthetist and the surgeon, with the anesthetist, as arule, concerned primarily with the prevention of shock and pulmonarycomplications. In times of stress, however, he was obliged to take over theentire responsibility for postoperative care, including nasogastric suction, themaintenance of an adequate fluid balance, thoracentesis for the removal of fluidand air, to facilitate the pulmonary exchange, and the administration of drugs.The essentials of the postoperative regimen are discussed elsewhere.
Postoperative pulmonary complications which occurred within the first 48hours after operation were classified as of anesthetic origin. Atelectasis(table 31, p. 206) was most frequent. In most instances, the condition wastransitory and cleared uneventfully. No deaths occurred from this cause alonewithin the specified 48-hour period. The atelectasis found at autopsy and notrecognized ante mortem in 12 fatalities which occurred within this period wasregarded as an incidental rather than a causative factor; all the patients hadserious injuries and other serious postoperative complications.
Prophylaxis against atelectasis included the measures already listed; thatis, voluntary coughing, frequent changes of position, measures to relieve pain,and the administration of oxygen. Atropine was also frequently administered,though not if the patient presented any signs of increased pulmonarytransudation.
Lobar pneumonia and bronchopneumonia were infrequentcomplications (p. 206). They might have been expected to occur more oftenfollowing prolonged anesthesia and operation, especially since, as alreadynoted, the patients had often been fighting in intolerable weather; had sufferedlong periods of exposure before, and sometimes after, wounding; and often hadpreexisting upper respiratory infections or tracheobronchitis. Undoubtedly, theprophylactic measures employed routinely after operation and the routine use ofpenicillin and the sulfonamides prevented serious consequences, even in thesecases.
ANESTHETIC-CONNECTED DEATHS
The majority of the 86 deaths which occurred on the operating table (11.4percent of the total number of fatalities) were caused by shock, hemorrhage, orfulminating infection. Nine, however, were attributable to anesthetic causes. Insome of these fatalities, the position had been changed just
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before death occurred. In four instances, the patients vomited and aspiratedgastric contents. Two similar fatalities, incidentally, occurred on the wardsshortly after operation; the patients had not completely reacted, and thefatalities must be charged to inadequate supervision. The same accident occurredin four other cases in which the patients survived.
Two deaths occurred at the conclusion of the operation, during bronchoscopy,presumably from a vagovagal reflex. These cases represented 0.4 percent of the436 recorded bronchoscopies. The vagovagal reflex is a foreseeable catastrophe,and in each of these cases it had been guarded against by the usual measures,namely, intravenous atropinization just before bronchoscopy was undertaken;light anesthesia; and rapid, careful instrumentation, so that mechanicalstimulation of the cough reflex would aid in clearing the air passages. Inspite of these precautions, a vagovagal reflex ensued and proved fatal.
