CHAPTER XVI
Factors of Mortality
W. Philip Giddings, M. D., and Luther H. Wolff, M. D.
The most dreaded complication of abdominal wounds in World War I wassepsis, which usually took the form of peritonitis. Sepsis and hemorrhagewere apparently the major causes of postoperative deaths in that conflict. Shockwas not a prominent cause. When it is recalled, however, that in World War Ipatients were frequently selected for surgery according to their chances ofsurvival, and that forward hospitals maintained so-called moribund wards1forthe care and comfort of the hopelessly wounded, this is easily understood.
In this series of abdominal injuries sustained in World WarII, postoperative sepsis caused only 91 deaths, 12.3 percent of the total number(table 33), andpostoperative hemorrhage was not at all common. Shock, on the other hand, was apredominant cause of death, being responsible for 64.0 percent of all the fatalities.This is an index of the penalty paid, in terms of surgical mortality, foradherence to the policy of offering to every casualty the possible benefits ofoperation.
The lack of selection of patients for surgery (p. 87) inevitably led to a certainincrease in the number of surgical deaths, especially during the induction ofanesthesia and in the course of operation. In almost none of the 756 recorded fatalities, however, wasit thought that surgery in itself had been responsible for the fatal outcome. Onthe contrary, in practically every fatal case the feeling was that death wouldsurely have occurred if operation had not been undertaken. Moreover, agratifyingly large number of even the most critically wounded men survived theirinjuries because they were operated on; they would certainly have died ifsurgery had been denied them. Many of them, although they were gravely ill forthe first few days after operation, had, so far as is known, no disabling orcrippling sequelae. Of the 3,154 casualtieswith abdominal wounds operated on by the 2d Auxiliary Surgical Group during 1944and 1945, a very large number were savedfrom certain death by surgery, and most of them were left with no significantphysical abnormalities.
It is important to emphasize again that the 756 deaths known to have occurred inthis series are only those which occurred in forward hospitals, in which urgentinitial surgery was performed and in which the usual postoperative stay was 8 to14 days, with a range of 1 to 30days. Additional deaths undoubtedly occurred in installations farther to therear, though the exact number is not known, followup of these patients havingproved impractical (p. 85).
1The Medical Department of the United States Army in the World War.Washington: U.S. Government Printing Office, 1927, vol. XI, pt. 1, p. 451.
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Cause |
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Shock | 83 | 268 | 118 | 3 | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | 472 | 64.0 |
Thoracopulmonary (all) | 3 | 4 | 5 | 20 | 15 | 14 | 10 | 7 | 8 | 5 | 3 | --- | --- | 3 | 97 | 13.2 |
Peritonitis | --- | --- | 6 | 20 | 13 | 10 | 10 | 6 | 7 | 5 | 4 | 4 | 1 | 5 | 91 | 12.3 |
Anuria | --- | --- | --- | 4 | 9 | 5 | 9 | 2 | 2 | 2 | 1 | --- | 1 | --- | 35 | 4.8 |
Anaerobic infection | --- | 1 | 1 | 2 | 3 | 1 | 1 | 2 | --- | --- | --- | 1 | --- | --- | 12 | 1.6 |
Other | --- | 4 | 2 | 2 | 5 | 5 | 2 | 3 | 2 | --- | --- | 2 | --- | 3 | 30 | 4.1 |
| 86 | 277 | 132 | 51 | 45 | 35 | 32 | 20 | 19 | 12 | 8 | 7 | 2 | 11 | 737 | 100.0 |
Proportion (culmulative) | 11.7 | 49.3 | 67.2 | 74.1 | 80.2 | 84.9 | 89.3 | 92.0 | 91.6 | 96.2 | 97.3 | 98.2 | 98.5 | 100.0 |
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1Nineteen cases in which the data on these pointswere incomplete are excluded from this table.
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It is thought that an additional 2 percent (approximate) ofthe patients in the entire series of 3,154 cases died in forward hospitals butwere unreported, and it should therefore be borne in mind that the rates citedthroughout this report are actually somewhat lower than the true rates.
Although factors of mortality are discussed under various other headingsthroughout this report, it seems profitable to comment upon them again under ageneral heading.
GENERAL CONSIDERATIONS
Type of wound-The gross case fatality rate for the 2,315cases in this series in which the injuries were confined to the abdomen was 23.2percent, and for the 839 thoracoabdominal injuries, 26.2 percent (table 6, p.91). There was some improvement in the rates in both categories as the warprogressed, more notably in thoracoabdominal injuries, as the result of theteaching and example of the thoracic surgical teams. In this type of wound, thecase fatality rate fell from 28.2 percent in 1944 to 20.0 percent in 1945. Thegeneral improvement in the whole series can be explained on several validgrounds: (1) The increasing experience of the surgeons who cared for thecasualties, (2) the advent of penicillin, and (3) the establishment of a theaterblood bank.
Site of hospitals-The discrepancy (table 5, p. 89) between the casefatality rate in field hospitals (24.3 percent) and in evacuation hospitals(15.1 percent) is readily explained by the fact that the farther forward amilitary hospital was located the greater was the number of severely wounded whosurvived to reach it and the more serious was their surgical risk. Thesignificance of the multiplicity factor in this connection has been discussedelsewhere (p. 110). Among the men who died in field hospitals were many who weremortally wounded but who were operated on because of the theater policy, whichwas based on the conviction that surgery offered the best chance of survival toall casualties with abdominal wounds.
Age-In the military-age group (roughly 20 to 40 years), there was aslight but steady rise in the case fatality rate as age increased, ranging from20.5 percent in the first 5-year group to 26.9 percent in the last (table 34).Deaths before and after the military age period occurred, for the most part, incivilians, and the higher rates are to be explained by the unfavorable reactionof young children and aging persons both to injury and to subsequent surgery.Civilians were often brought to treatment late, and their physical state wasgenerally poorer than that of American troops. The large group of patients whoseage was not recorded and a large proportion of whom died consisted chiefly ofcivilians and prisoners of war, and the lack of data is explained by linguisticdifficulties.
Shock-The case fatality rate of these abdominal injurieswas in proportion to the state of shock in which the patients were admitted (p.121). It was 18.2 percent among patients not in shock or in minimal shock and66.4 percent among those in profound shock (table 18, p. 121).
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TABLE 34.-Distribution of injuriesand deaths according to age in 3,154 abdominal injuries
Age (years) | Cases | Deaths | Case fatality rate |
0 through 20 | 707 | 164 | 23.2 |
21 through 25 | 987 | 202 | 20.5 |
26 through 30 | 591 | 139 | 23.5 |
31 through 35 | 250 | 60 | 24.0 |
36 through 40 | 78 | 21 | 26.9 |
Over 40 | 42 | 18 | 42.9 |
Not stated | 499 | 152 | 30.5 |
| 3,154 | 756 | 24.0 |
Season-It wasa repeated clinical observation that casualties received at field hospitalsduring the cold, wet winter months were likely to be in a more severe state ofshock than men with comparable wounds during the summer months. Their poorerstatus was undoubtedly caused, at least in part, by exposure and by difficulties(and consequent slowing) of transportation. In addition, infectious pulmonarycomplications were almost a third more frequent in the winter, when chronicbronchitis and tracheitis seemed almost universal among frontline infantrymen(p. 204).
These circumstances were reflected in the difference in thecase fatality rates for the winter months (October through March) and the summermonths, which were, respectively, 27.4 and 19.9 percent(table 35). The casualties for August 1944 werelower in actual numbers than for any other month (fig. 15, p.90), but the case fatality rateshowed a rise. The explanation is that most of the injuries were incurred duringthe landings in southern France, when some delay in the establishment andoperation of hospital facilities was in
TABLE 35.-Seasonal distribution ofcases and deaths in 2,332 abdominal injuries (1944)
| Months | Cases | Deaths | Case fatality rate |
January-March | 430 | 141 | 32.8 |
| April-June | 470 | 91 | 19.4 |
| July-September | 503 | 103 | 20. 5 |
| October-December | 929 | 232 | 25.0 |
| 2,332 | 567 | 24.3 |
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evitable. A sharper peak in the case fatality rate duringFebruary 1944 can be explained by similar difficulties in the early phase of theoperation on the Anzio beachhead.
SPECIAL FACTORS OF MORTALITY
It has already been noted that when these 3,154 abdominal injuries werestudied as a whole and the case fatality rate was plotted against the timeinterval from wounding to operation (timelag), the inimical effect of delay wassurprisingly slight (fig. 20, p.104). This was contrary to expectations and was not in accord with clinicalobservations.
The explanation was found in the multiplicity factor (p. 105). An analysis ofcases from the standpoint of the number of organs injured revealed an almostarithmetical increase, of approximately 15 percent, in the case fatality ratewith each additional viscus injured (fig. 21, p. 108). The rate rose from 7.5percent when there was no visceral damage and 14.9 percent when only a singleviscus was injured to 100 percent when 6 organs were injured.
When the cases were analyzed in exclusive categories from the jointstandpoint of the multiplicity factor and the timelag (table 9, p. 106), itbecame apparent that the prognosis was gravely affected by a prolonged timelag.In univisceral injuries, the case fatality rate was 10.1 percent for the first 8hours, 14.8 percent for the second, and 16.6 percent for the third. At the endof 36 hours, the rate was 26.4 percent. The cases in other categories ofmultiplicity followed essentially similar patterns of increase.
Superficially, the case fatality rate did not seem to be materially affectedby the presence of coincidental extra-abdominal wounds. Here again, however, adifferent conclusion resulted when the multiplicity factor was taken intoaccount. When the analysis was made from this standpoint, there was an averageincrease of approximately 3.9 percent in each category in the presence ofassociated wounds (fig. 23, p. 116).
Multiplicity of injuries was also found to influence the case fatality ratewhen the calculations were made on the type of organ injured (p. 95) and theparticular organ injured (table 36). Rates for special organs are discussed indetail under the appropriate headings, but it should be emphasized here that themost reliable conclusions concerning the lethality of wounds of individualorgans are obviously drawn from data relating to univisceral wounds. The type oforgan injured definitely influenced the case fatality rate, univisceral injuriesof hollow viscera being more lethal (17.4 percent) than those of solid viscera(11.1 percent).
It is unfortunate that figures are not available to permitdetailed comparisons, on the basis of the number of viscera injured, of theabdominal injuries treated by the 2d Auxiliary Surgical Group and other recordedseries. Such comparisons as are possible are presented in table 37.
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TABLE 36.-Case fatality rates according to viscus wounded in 3,154 abdominal injuries
Organ injured | Univisceral wounds | Multivisceral wounds | Total | ||||||
Cases | Deaths | Case | Cases | Deaths | Case | Cases | Deaths | Case | |
Stomach | 42 | 12 | 28.6 | 374 | 157 | 42.0 | 416 | 169 | 40.6 |
Duodenum | 2 | 0 | 0 | 116 | 67 | 57.8 | 118 | 67 | 56.8 |
Jejuno-ileum | 353 | 49 | 13.9 | 815 | 296 | 36.3 | 1,168 | 345 | 29.5 |
Colon only | 251 | 57 | 22.7 | 816 | 329 | 40.3 | 1,067 | 386 | 36.2 |
Rectum only | 64 | 9 | 14.1 | 52 | 18 | 34.6 | 116 | 27 | 23.3 |
Colon and rectum | 13 | 6 | 46.2 | 26 | 14 | 53.8 | 39 | 20 | 51.3 |
Liver | 339 | 33 | 9.7 | 490 | 191 | 39.0 | 829 | 224 | 27.0 |
Gallbladder | 0 | 0 | (1) | 53 | 16 | 30.2 | 53 | 16 | 30.2 |
Pancreas | 1 | 1 | 100.0 | 61 | 34 | 55.7 | 62 | 35 | 56.5 |
Spleen | 100 | 12 | 12.0 | 241 | 73 | 30.3 | 341 | 85 | 24.9 |
Kidney | 56 | 9 | 16.1 | 371 | 146 | 39.4 | 427 | 155 | 36.3 |
Ureter | 1 | 0 | 0 | 26 | 11 | 42.3 | 27 | 11 | 40.7 |
Bladder | 21 | 0 | 0 | 134 | 46 | 34.3 | 155 | 46 | 29.7 |
Great vessels | 8 | 5 | 62.5 | 67 | 50 | 74.6 | 75 | 55 | 73.3 |
| 1,238 | 187 | 15.1 | 1,916 | 569 | 29.7 | 3,154 | 756 | 24.0 |
1Case fatality rate not applicable.
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TABLE 37.-Case fatality rates of visceralwounds in various recorded series of abdominal injuries1
TIME AND CAUSE OF DEATH
Three hundred and sixty-three of the 737 deathsin this series (49.3 percent)in which these data were available for analysis occurred on the day of operation(table 33). Eighty-sixpatients died on the operating table, four of them during the induction ofanesthesia and the remainder during the procedure or within 10 minutes of itsconclusion. The remaining 227 casualtiesin this group died within 24 hoursafter operation. Almost three-quarters of all the deaths occurred within 72 hours of operation. Thereafter,the number decreased with each succeeding day. The preponderance of fatalitiesduring operation and within the immediate postoperative period is a clear indexof the severity of the wounds.
The majority of deaths which occurred within 72 hoursof operation were ascribed to shock, which accounted for 472(64.0 percent) of the 737 deaths available for analysisfrom this standpoint. Included in this group of fatalities are 64 deaths in which the principalcause of shock was acute hemorrhage, as well as smaller numbers caused by shockattributable to severe peritoneal con-
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tamination, cardiorespiratory embarrassment, cardiovascular injuries, severecerebral injuries, blast injuries to the lungs, and other less commonshock-producing injuries. In slightly more than half of these deaths, no singleshock-producing factor could be identified. The fatality seemed to be caused bythe interaction of hemorrhage, peritoneal contamination, and tissuedestruction.
Thoracopulmonary complications, which were the cause of 13.2 percent of all deaths, consisted chiefly of pneumonitis, atelectasis, empyema,and pulmonary embolism. Their frequency was found to be related, at least inpart, to the severity of the wound and the timelag, but their incidence rose inrelation to the increasing multiplicity of visceral injuries (table 32, p. 206).
Peritonitis, which was responsible for 12.3 percent of alldeaths, was most frequent in patients with an unusually prolonged timelag. Thisis what might be expected because the longer peritoneal contamination exists,the greater is the likelihood that a virulent peritonitis will develop. Itshould be emphasized again that the peritonitis responsible in this series fordeath after the third postoperative day was the type of bacterial processordinarily seen in civilian practice, not the type caused by overwhelmingcontamination associated with shock and responsible for death soon afteroperation.
Anuria (lower nephron nephrosis, hemoglobinuric nephropathy),which was responsible for 4.8 percent of the deaths, does not seem to have beenrecognized as a clinical entity in World War I. It usually occurred in patientswho were in severe shock when they were first seen, in whom resuscitation hadbeen difficult, and who had required massive replacement therapy (p. 131). Thesefatalities seemed closely related to the fatalities which occurred earlier fromshock. The patients escaped death, but at this time the physiologic changeswhich ultimately proved fatal were apparently established.
Miscellaneous causes of death, which accounted for 4.1percent of the total number, included associated wounds and surgical andanesthetic complications. As individual causes of death, they cannot be said tohave had more than a slight influence on the case fatality rate for the seriesas a whole.
ULTIMATE CAUSES OF DEATH
The case fatality rate in any series of injuries is a composite expression ofthe interaction of all the lethal factors in each individual case. By theclassification of the 3,154 injuries of the abdomen treated by the 2d AuxiliarySurgical Group into exclusive categories, it has been possible to demonstratethat the most important factors in this series were apparently as follows:
1. The original severity of the wound, as it affected oneorgan or several. Though this was the most significant determinant of lethalityin every case, it cannot be expressed graphically.
2. The number of organs injured. In the statistical analysisof this material, the clinical impression was immediately confirmed that thegreater the number of organs injured, the higher was the case fatality rate.This factor is susceptible of statistical analysis.
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3. The timelag, or the period from wounding to surgery. This factor, while itis susceptible to statistical analysis, is reliable only when it is related tothe severity of the wound, expressed in terms of the number of viscera injured.The more severe the wound, the greater was the danger from a prolongation of thetimelag and the graver was the prognosis.
4. The state of shock on admission. Almost three-quarters of all deaths inthis series occurred within 72 hours after the patients were admitted to thehospital, and almost all of the fatalities in this group were attributable toshock. The more severe the state of shock, the graver was the prognosis.
Inanalyzing the factors of mortality in this series of abdominal injuries, it wasimmediately apparent, when the less frequent causes of death were excluded, thatthe most important lethal influence was the original severity of the wound.Since it was not possible to reduce severity to statistical terms, the mostpractical way to express it was in terms of the number of viscera injured; thatis, the multiplicity factor, which is granted to be only an approximation. Thesecond most important lethal factor was the timelag. The correlating factorbetween the multiplicity factor and the timelag was the degree of shock, whichcan be roughly defined as the manifestation of the effects of a wound of givenseverity affecting a casualty for a given length of time. Death caused by shockwas the extreme manifestation of the combined effects of the multiplicity factorand the timelag.
The highest case fatality rates in this series occurred intwo groups of patients: (1) Those who presented a high multiplicity factor, withinjuries of four or more viscera, and (2) those admitted in severe shock.Actually, the two groups were usually one and the same because the greatestfrequency of severe shock was observed in patients with the highest multiplicityfactors. Patients with wounds of this kind were seldom seen after a prolongedtimelag, for the reason that, if they did not reach the hospital promptly, theydied before they could be brought to it.
A consideration of these facts leads to a conclusion quite inaccord with clinical observations and also supported by the fact thatapproximately threequarters of the deaths in forward surgical hospitals occurredwithin a relatively short period (72 hours) after operation. This conclusion isthat the combined effects of a severe wound and of a prolonged timelag werelikely to be lethal, regardless of the best resuscitative and surgical efforts.
