CHAPTER VIII
Pigment Mobilization in Severely Wounded Men
It was shown in Chapter IV that severely wounded men commonly excreteheme-containing pigments, either hemoglobin or myoglobin, in the urineand that such excretion was constantly observed in patients destined todevelop the syndrome of posttraumatic renal insufficiency. In Chapter IXthe significance of pigment excretion will be further emphasized by demonstratingthat pigment precipitation in the lower segments of the nephrons was aconstant feature of the renal lesion observed in fatal cases. The importanceof pigment mobilization, its transport via the plasma to the kidneys, andits excretion in the urine was therefore obvious early in our investigations,and the present chapter will be devoted to presentation of the availabledata and discussion of their significance.
Materials and Methods
We were severely handicapped by the lack of a spectroscope of sufficientsensitivity to distinguish between the closely similar spectrums of hemoglobinand myoglobin, and even if a suitable instrument had been available itis doubtful if it could have been utilized under field conditions. We resortedtherefore to use of the benzidine method, which gave a color reaction strongenough to read in a Coleman Junior spectrophotometer in a dilution of 1milligram of benzidine-positive material per 100 cubic centimeters. Themethod did not, however, permit distinction between myoglobin and hemoglobinin plasma, so throughout this chapter the term "plasma hemoglobin" is usedto indicate the total amount of benzidine-reacting material, though inmany instances a significant proportion was undoubtedly myoglobin. A furthersmall fraction of the total was probably contributed by nonspecific oxydases,but it is improbable
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that this was large enough to affect comparative results. Under theseconditions, results of the test were always positive for "hemoglobin,"ranging from 6 to 12 mg. per 100 cc. in the majority of initial samplesand also in samples procured during convalescence. We therefore consideredvalues up to 12 mg. per 100 cc. as being within normal range.
In the urine it did prove possible to distinguish between the two pigmentswithin certain limits by taking advantage of the greater stability of myoglobinin alkaline solutions. By cautiously alkalinizing the urine, hemoglobincould be converted to alkaline hematin and precipitated while the greaterportion of the myoglobin remained in solution. Tests with known mixturesof the two pigments showed that the separation was approximately 80-percenteffective, and analyses of normal and decolorized muscles from patientswho died of the crush syndrome provided further confirmation of the validityof the method. When enough pigment for quantitative determination was presentin a urine specimen, this method was applied. Values of "myoglobin" thatwere less than 20 percent of the hemoglobin present were considered negative;findings of 20 percent or more were recorded as myoglobin. Details of themethods used will be found in Appendix C.
Determinations of plasma "hemoglobin" and of urine hemoglobin and myoglobinwere made routinely upon all patients in the series from whom suitablespecimens could be obtained. In some instances high plasma values wereundoubtedly due to hemolysis incurred in taking samples of blood. Greatcare was used in cleaning and drying needles and syringes and in the techniqueof venepuncture, but needles and syringes were not paraffinized. In certainpatients injury to the kidney or other portion of the urinary tract resultedin gross hematuria, and urine hemoglobin levels in these cases were consideredvalueless; however, if myoglobin was discovered in such specimens, it wasrecorded.
Bank Blood
Since hemolysis is inevitable in stored blood, many samples of bankblood, taken at the time the blood was given out for transfusion to ourpatients, were analyzed. The plasma hemoglobin and the blood sugar levelswere determined, the latter in order to check upon the effectiveness ofadded dextrose as a preservative. Confirmation of the serologic blood groupof the bank blood was not attempted because the triple check used in thetheater blood bank was as ac-
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curate as any method we could have tried. We did, however, take theprecaution of checking the blood group of the recipient whenever possiblesince the "dog tags" were known to be approximately 8-percent erroneous,and since the grouping was often too difficult for hospital techniciansbecause of the large quantities of group O blood that some patients hadalready received before the first test-specimen was obtained.
Few Rh factor determinations were made because very little typing serumwas available. All patients, however, who were conscious at the time ofobservation were carefully questioned regarding previous transfusion andanswers were uniformly negative. Previous sensitization was therefore improbable,and the short duration of the period of transfusion therapy--from 1 to3 days--made active sensitization of no importance in our problem.
Specifications of Bank Blood.-Blood given to patients in thisstudy was derived from the theater blood bank in all but two instances.1All bank blood was group O and the plasma agglutinins against A and B cellshad been determined. If these were below 1:64, the blood was labeled UniversalDonor; if above this level, O-Blood, for Use in O-Recipients Only.The blood had been drawn into sodium citrate, and dextrose had been addedto give a concentration approximating 0.3 percent. Blood was stored atall times, including periods of transportation, in refrigerators at approximately8° Centigrade. It was never used after the tenth day.
Analyses of Bank Blood.-Since all blood samples contain cellsof varying maturity, progressive hemolysis is inevitable in all storedspecimens. This is apparent in Chart 29 and Table 84 which show averageplasma hemoglobin levels at the time of transfusion in 213 samples of bloodfrom 2 to 10 days old. The rate compares favorably with Gibson`s2figures based on storage in A-C-D solution. In occasional samples, usuallythose from 6 to 8 days old, considerable hemolysis was evidenced by plasmahemoglobin levels from 100 to 300 mg. per
1Case 9 was an example of a transfusion accident--A blood to an O recipient. The patient was seen in consultation at a neighboring hospital and was studied for comparison only. The second patient (Case 22) belonged to group A. He received three transfusions of bank blood in a forward hospital and subsequently was given 2 units of group A blood at a general hospital. He had already given evidence of renal insufficiency before the type-specific blood was administered.
2GIBSON, J. G., 2nd; EVANS, R. D.; AUB, J. C.; SACK, T., and PEACOCK, W. C.: The post-transfusion survival of preserved human erythrocytes stored as whole blood or in resuspension, after removal of plasma, by means of two isotopes of radioactive iron. J. Clin. Investigation 26: 715-738, July 1947.
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CHART 29. RELATIONSHIPBETWEEN FREE PLASMA HEMOGLOBINAND AGE OF STORED BLOOD-213SAMPLES
100 cc. (see Charts 30, 31, and 32). The average levels in samples from5 to 8 days old, the age period of most of the blood used, were in therange from 38 to 50 milligrams per 100 cubic centimeters.
The possible effect of blood transfusions on the level of free hemoglobinin the blood plasma of the recipients is made readily apparent by a fewsimple calculations. Since the average amount of free hemoglobin in thebank blood at the time of transfusion was approximately 40 mg. per 100cc., and 500 cc. of blood was the amount per unit, each patient receivinga unit of blood received at the time 200 mg. of free hemoglobin. Our patientsreceived an average of 4.2 units of blood, or 840 mg. of hemoglobin, andin the fatal cases an average of 7.3 units, or 1,460 mg. of hemoglobinwas given. Seven patients received from 10 to 14 units, or 2,000 to 2,800mg. of free hemoglobin. Assuming an average blood volume to be 5,000 cc.,such quantities of infused hemoglobin could have resulted in plasma levelsof free hemoglobin in the patients of 16 to 58 mg.
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per 100 cubic centimeters. It must not be forgotten, however, that theseapproximations are based on the assumption that all infused free hemoglobinwould remain in the circulating plasma. This would certainly not be true,since in many patients significant quantities would be excreted in theurine and in all instances some would escape with the plasma into traumatizedtissues.
TABLE 84.-RELATIONSHIP OFAVERAGE PLASMA HEMOGLOBINLEVEL TO AGE OF STOREDBLOOD-213 ANALYSES
Charts 30 through 33 show the relationship between hemolysis and sugarlevels in the stored blood. It is evident that most instances of extremehemolysis occurred in blood samples with low sugar levels. Table 85 andChart 33 show average sugar levels in relationship to age of the blood.The chart shows that the sugar level was well maintained until the seventhday and dropped sharply thereafter.
TABLE 85.-RELATIONSHIP OFAVERAGE BLOOD SUGARTO AGE OF STORED BLOOD-223SAMPLES
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CHART 30. Relationship between Plasma Hemoglobinand Blood Sugar in Blood Stored 6 Days-52 Samples
CHART 31. Relationship between Plasma Hemoglobinand Blood Sugar in Blood Stored 7 Days
CHART 32. Relationship between Plasma Hemoglobinand Blood Sugar in Blood Stored 8 Days
CHART 33. Relationship between Blood Sugar andAge of Stored Blood-223 Samples
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Plasma "Hemoglobin" Levels in Wounded Men
The pattern of plasma "hemoglobin" (benzidine-reacting material) levelsin severely traumatized men is shown in Charts 34 through 37. In Chart34, based upon findings in 133 patients, the mean plasma hemoglobin levelfor each day after injury is plotted. From an initial figure of 10 mg.per 100 cc., it climbs in 72 hours to 17.3 mg., then slowly falls in thecourse of the next 13 days to a level of 3 mg. per 100 cc. of plasma. Chart35 shows daily mean levels of 64 patients who had high azotemia, over halfof whom died. The curve is essentially similar, though the peak is higherand is delayed 24 hours. In Chart 36 only the fatal cases with histologicallyproved pigment nephropathy are shown, exclusive of crush cases. In thisgroup the peak is sharp and high, occurring at 24 hours and attaining amaximum of 36.8 mg. per 100 cubic centimeters. This figure is still farbelow the generally accepted threshold level of 135 mg. per 100 cc. atwhich a normal kidney begins to excrete hemoglobin.3 4 5
The plasma bilirubin level as determined by the van den Bergh diazotest has also been plotted on these charts, omitting cases of direct livertrauma. As would be expected, the bilirubin curve roughly paralleled thatof hemoglobin but its peak occurred from 3 to 4 days later. Strict parallelismcould not be expected since the bilirubin level is also affected by efficiencyof liver function; evidence of liver injury in these patients is presentedin Chapters II and XII.
In considering the significance of the plasma hemoglobin levels, twopossible relationships at once come to mind: does the level depend uponthe severity of shock? or upon the quantity of blood the patient was given?The answer is not obvious since the patients with the most severe shockusually received the most blood. Available evidence compiled from the firstspecimen of blood obtained for analysis is presented in Table 86. The followingcases have been excluded: all crush cases, in which benzidine-reactingpigment in the plasma
3GILLIGAN, D. R., and BLUMGART, H. L.: March hemoglobinuria; studies of clinical characteristics, blood metabolism and mechanism, with observations on three new cases, and review of the literature. Medicine 20: 341-395, September 1941.
4GILLIGAN, D. R.; ALTSCHULE, M. D., and KATERSKY, E. M.: Studies of hemoglobinemia and hemoglobinuria produced in man by intravenous injection of hemoglobin solutions. J. Clin. Investigation 20: 177-187, March 1941.
5OTTENBERG, R., and FOX, C. L., JR.: Rate of removal of hemoglobin from circulation and its renal threshold in human beings. Am. J. Physiol. 123: 516-525, August 1938.
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may be assumed to have been predominantly myoglobin, all cases in whichthe initial specimen was not obtained within 3 days of injury, and Case37 with several plasma hemoglobin levels above two hundred. This figurewas so completely out of line with all other cases that a unique and unexplainedmecha-
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nism of hemolysis must be assumed. Seventy-six cases were availablefor analysis after these exclusions.
In compiling the table, the patients were divided into three groups:(1) those who had received no blood transfusion prior to drawing of thefirst blood specimen for analysis; (2) those who had received small tomoderate amounts of blood-from 1 to 3 units or 500 to 1,500 cc.--and (3)recipients of large quan-
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tities of blood--from 4 to 14 units or 2 to 7 liters. Shock had beenestimated in three grades of severity, and there were a few patients withoutshock. The
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CHART 37. AVERAGELEVELS OF PLASMA "HEMOGLOBIN"ANDBILIRUBIN RELATED TO TIMEFROM WOUNDING IN 107 PATIENTSOF BLOOD GROUPS A ORO
number of cases in some shock categories was so small, however, thatonly two categories were utilized: (1) patients with no shock or only slightshock (the minimal-shock" group), and (2) patients with moderate or severedegrees of shock. Data are shown separately for blood samples drawn within24 hours of injury and those taken from 24 to 96 hours after injury.
It is apparent from inspection of the table that plasma hemoglobin levels
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during the first 24 hours after injury showed no elevation which couldbe attributed either to shock or to infusion of bank blood. The mean plasmahemoglobin level for the entire group examined within 24 hours of injurywas 9.6 mg. per 100 cc. of plasma, a normal figure for the technique used(See Materials and Methods). The mean for the moderate-and-severe shockgroup (8.8) was actually lower than the mean (11.7) of the minimal-shockgroup. More surprising are comparisons based on the quantity of transfusedblood. The plasma hemoglobin levels actually appear to decline from a meanof 11.1 mg. per 100 cc. in the 14 patients who had received no blood to9.2 in 22 patients who had had from 1 to 3 transfusions, and a minimumlevel of 7.5 in the 5 patients who had received the largest quantitiesof blood--from 4 to 14 units. These apparently paradoxical differencesare not statistically significant, but it is clear that in this study noevidence emerged to indicate that during the first 24 hours after injuryinfused hemoglobin from stored blood produced any rise in plasma hemoglobinconcentration.
In the succeeding 3 days, from 24 to 96 hours after injury, some risein plasma hemoglobin was usually apparent. The average for the 35 casesin this category was 16.9 mg. per 100 cc. of plasma. Once again no evidencewas obtained that shock per se produced any mobilization of hemoglobin.The mean of 17.3 mg. per 100 cc. for the moderate-and-severe shock groupis not appreciably greater than the 16 mg.-figure for the minimal-shockcategory. In contrast to the findings in the first 24 hours, however, theredoes appear to be evidence that the plasma hemoglobin level rose in proportionto the quantity of transfused blood. It rose from a mean of 9.2 mg. per100 cc. in the patients who had received no blood, to 15.1 in those whohad received from 1 to 3 units, and to 20.5 in the patients treated with4 or more transfusions. The difference between the first and third of thesemeans, 11.3, is more than three times the standard error of 3.08.
In summary, the initial plasma free-hemoglobin levels of 76 woundedmen who had had various degrees of shock, and who had received from noneto 14 units of bank blood before the first sample of plasma was obtainedfor analysis, showed no rise in plasma hemoglobin concentration within4 days after injury that could be attributed to the state of shock. Duringthe first 24 hours after injury, the plasma hemoglobin concentration wassurprisingly constant regardless of the amount of blood the patients hadreceived. Hemoglobin in solution in the plasma of the infused bank bloodwas therefore not sufficient
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to raise the plasma hemoglobin level of the recipient. After the first24 hours, plasma hemoglobin levels did rise in the majority of patients.This rise could not be correlated with the degree of shock but did showan apparently significant correlation with the amount of transfused blood.Such a delayed hemolytic action could be due either to nonspecific, acceleratedhemolysis of the infused group O red cells or to hemolysis of the recipients`red cells from accumulation of infused iso-agglutinins. Evidence bearingupon this possibility will be presented in the following section.
Iso-Agglutinins
Relationship to Pigment Nephropathy
In Chart 37, the mean plasma hemoglobin level of 56 patients belongingto blood-group A is compared with that of 51 patients belonging to blood-groupO. A distinct peak in the former curve on the third and fourth days afterinjury is apparent. On the third day the mean level in the A group was24 mg. of hemoglobin per 100 cc. of plasma as compared with 10 mg. per100 cc. for the O group at the same period. The difference is large enoughto indicate some degree of hemolysis due to a-agglutinins. No reasonis apparent for the rather surprising delayed rise in plasma hemoglobinconcentration in the O group, which appears on the eighth day. The precipitatecharacter of this peak, with its sudden rise and drop and the lack of equivalentrise in the plasma bilirubin, suggests that this may reasonably be ascribedto inadequate sampling or technical error.
Relationship to Lower Nephron Nephrosis
If hemolysis due to iso-agglutinins in plasma or bank blood were ofimportance in the pathogenesis of lower nephron nephrosis, the lesion shouldhave appeared with greater frequency in our patients of blood-groups A,B, and AB than in those of group O, since all transfusions, with the twoexceptions previously noted, were of O blood. No evidence was obtainedof any relationship of blood group to case fatality or to development ofrenal insufficiency.
Blood grouping in the 186 patients in the study was checked in our laboratoryin 137 instances. The distribution of blood groups among these 137 patientsis
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shown in Table 87, both for all cases and for fatalities. It is evidentthat in both categories the distribution approximates closely the usualfigures for a sample of the American population. Equally negative evidenceof any effect of blood group is shown when the fatal cases of lower nephronnephrosis are considered. Blood group was known in 37 such cases whichare shown on the table. It is evident that the distribution again approximatesthat of an average population.
Hemoglobinuria and Myoglobinuria in Wounded Men
Relationship of Plasma Hemoglobin Levels to Excretionof Hemoglobin in the Urine
Excretion of hemoglobin in the urine is dependent upon two factors:the concentration of hemoglobin in the blood plasma and the permeabilityof the glomerular filter. As has already been pointed out, only one patient,Case 37, (crush cases excluded) showed a plasma hemoglobin concentrationabove 135 mg. per 100 cc., the usually-accepted threshold level for hemoglobinuria.An altered permeability of the glomeruli must therefore be assumed in allother patients manifesting hemoglobinuria. If the increase in permeabilitywas more
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or less constant, it might be expected that the degree of hemoglobinuriawould be influenced by the level of plasma hemoglobin. If the alterationin permeability was variable, no such relationship would be demonstrable.
The concentrations of hemoglobin in plasma and urine are compared inTable 88 for 21 cases in which the two determinations were made upon samplescollected at approximately the same time. The possibility that the urinemight have been retained within the bladder for many hours before voidingcould not always be excluded. No evidence of correlation is present, andthe Spearman rank order coefficient of correlation (rho) is 0.03, indicatingonly chance relationship between the two series of figures.
TABLE 88.-COMPARISON OF HEMOGLOBINCONCENTRATION IN PLASMA AND URINEIN 21 CASES
Excretion of Myoglobin in the Urine
Analyses for hemoglobin and myoglobin in the urine were carried outin 42 cases in which measurable amounts of benzidine-positive materialwere present. Myoglobin was positively identified in 19 cases and was thedominant pigment in nine. (Comparison was impossible in 5 of these becausewounds of the urinary tract made urine hemoglobin figures unreliable.)In 8 additional cases the test for myoglobin was positive but the proportionfound was so small (from 10 to 20 percent of the benzidine-reacting material)that the results were classed as doubtful and were disregarded. The analysesin the remaining 15 cases were recorded as definitely negative (myoglobinfrom 0 to 10 percent).
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The 19 positive cases are listed in Table 89 together with the degreeof shock, the concentration of myoglobin and hemoglobin in the urine, thelevel of benzidine-positive material in the blood plasma, and the majorclinical diagnoses.
TABLE 89.-OCCURRENCE OF MYOGLOBINURIAAND CORRELATIVE FINDINGS IN19 SEVERELY WOUNDED PATIENTS
Inspection of this table reveals several points of interest. As in thecase of hemoglobinuria, it is obvious that there is no correlation betweenthe level of benzidine-positive material in the plasma and the amount ofmyoglobin excreted in the urine. For example, in Case 38 only 4.3 mg. per100 cc. were found
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in the plasma, while the urine contained the enormous concentrationof 420 mg. per 100 cubic centimeters. In Case 78, a patient with crushsyndrome, the situation was reversed. The plasma concentration was 920mg. per 100 cc., the maximal figure of the entire series, whereas the urinecontained barely enough to measure--only 2.5 milligrams.
If the myoglobinuric cases are considered as a whole, the degree ofmyoglobinuria shows no relationship to the severity of shock. In the "minimal-shock"group (as previously defined), the concentrations of myoglobin in the urineranged from 2.5 to 588.0 mg. per 100 cubic centimeters. In the moderate-and-severeshock group, the range was from 1 to 420 mg. per 100 cubic centimeters.The average of seven cases in the minimal-shock group was 321 mg. in comparisonwith 63.7 mg. for the more severe-shock group, but with such wide variationin the data the averages are meaningless.
TABLE 90.-RELATIONSHIP OFMUSCLE NECROSIS TO SHOCKIN 19 PATIENTS WITH MYOGLOBINURIA
When the nature of the major injury or lesion in these myoglobinuriccases is taken into consideration, however, an interesting correlationdoes become apparent. The cases fall readily into two groups: those withextensive necrosis of skeletal muscle (either ischemic or infectious) andthose without such muscle necrosis. They are so listed, with the estimateddegrees of shock, in Table 90.
Five of nine patients with extensive necrosis of skeletal muscles showedminimal or no clinical evidence of shock; in those without extensive muscle
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necrosis, in contrast, eight were in the moderate-and-severe shock groupand only two in the minimal-shock group. One of the latter, Case 74, withextensive burns showed sufficient hemoconcentration to suggest a more severegrade of shock than was clinically apparent. These findings strongly suggest,on the one hand, that myoglobin is rarely liberated in the absence of shockunless there has been extensive necrosis of skeletal muscle, and on theother, that in the presence of severe shock, there is some mechanism forits mobilization other than muscle necrosis.
Relationship of Hemoglobinuria to Myoglobinuria
Attempts to correlate the variety of pigment excreted in the urine withthe type of injury or lesion provided extremely puzzling results, as maybe seen from the tabulation to follow in which cases have been classifiedby the predominant pigment, though many of them showed simultaneous excretionof both pigments. Because of the frequency of multiple injuries, the samecase has often been included under more than one heading. Cases of traumato the urinary tract have been excluded from the hemoglobinuric but notfrom the myoglobinuric category.
|
Type of injury or complication |
Number predominantly hemoglobin |
Number predominantly myoglobin |
|
Crush syndrome |
2 |
3 |
|
Wounds of extremity |
19 |
5 |
|
Major vascular interruption |
11 |
3 |
|
Clostridial myositis |
1 |
2 |
|
Urinary tract injury |
--- |
2 |
|
Liver injury |
4 |
1 |
|
Abdominal wound |
11 |
3 |
|
Peritonitis |
4 |
3 |
|
Burn |
0 |
1 |
|
Volvulus |
0 |
1 |
It is at once evident that any type of injury may be associated with either hemoglobinuria or myoglobinuria and that in most types, except the crush syndrome and in clostridial myositis, the former is by far the more common. It is noteworthy that in two typical crush cases no evidence of myoglobin excretion was obtained (see Chapter XI). Neither massive trauma to the extremities nor interruption of a major vessel, with consequent ischemic necrosis of muscle,
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usually resulted in predominant myoglobinuria, and in two of the threepatients in whom it did appear, a successful arterial anastomosis had re-establishedcirculation of the leg before myoglobinuria was observed. In three patients(Case 70, extensive but superficial burns; Case 38, volvulus, and Case9, mismatched transfusion) injury of voluntary muscle can be absolutelyexcluded. In considering the findings, however, it must be remembered firstthat our test for myoglobinuria was crude and results were recorded aspositive only when considerable quantities of myoglobin were present, andsecond that myoglobin is rapidly excreted in the absence of renal insufficiencyand the loss of a single urine specimen might cause a falsely negativeresult.
TABLE 91.-GREATEST CONCENTRATIONS1OF HEMOGLOBIN AND MYOGLOBINOBSERVEDIN THE URINE
One final comparison is of interest. In Table 91 the 12 patients showingthe highest concentrations of hemoglobin and the 12 with the highest myoglobinconcentrations are listed. As before, cases of trauma to the urinary tracthave been eliminated from the hemoglobinuric category. It is apparent fromthese figures that myoglobinuria was frequently massive whereas hemoglobinuriawas rarely so when cases of direct trauma to the urinary tract are eliminated.It is also noteworthy that four cases (Cases 38, 70, 74, and 93) appearin both lists, suggesting that the conditions for the liberation of myoglobinand of hemoglobin may not be unrelated.
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SUMMARY
The concentration of benzidine-reacting heme pigment in the blood plasma(recorded as plasma hemoglobin) and the individual concentrations of hemoglobinand myoglobin in the urine were measured in our patients to determine theextent of pigment mobilization. These data, together with determinationsof plasma hemoglobin in the bank blood administered to the patients, wereanalyzed in an attempt to determine the mechanism of pigment mobilizationin the body and of pigment excretion by the kidney.
It was found that the bank blood used in therapy was in a satisfactorystate of preservation, with an average of only 43 mg. of free hemoglobinper 100 cc. of plasma at the moment of utilization. Even in patients whoreceived as many as 10 to 14 transfusions, the plasma "hemoglobin" levelsof the recipients showed in the first 24 hours no elevation which couldbe attributed to free hemoglobin in the transfused blood. Comparison ofthe plasma hemoglobin concentrations with the degree of shock in 76 patientsshowed no evidence that shock itself induced any immediate increase inplasma hemoglobin concentration.
Twenty-four hours after injury, however, a progressive rise in plasmahemoglobin began to be apparent which reached a peak between 48 and 72hours and then slowly dropped to normal over a period of 2 weeks. Thispeak was approximately twice as high (36.8 mg. per 100 cc.) in 33 casesof fatal nephropathy as in the series as a whole (17.3 mg. per 100 cc.)and occurred only 24 hours after wounding. No evidence was obtained thatit was higher in patients with severe shock than in those without shockor with only minimal shock. It was, however, significantly higher in patientswho had received multiple transfusions than in those who had received noblood.
Evidence that this delayed rise in plasma hemoglobin was largely dueto iso-agglutinins was afforded by comparison of group A and group O recipients.In 56 of the former, the mean plasma hemoglobin on the third day was 24mg. per 100 cc., whereas in a sample of 51 group O recipients the correspondinglevel was only 10.2 milligrams. This difference was of no significance,however, in the development of pigment nephropathy as shown by the percentagedistribution of blood groups among the nephropathies, which was essentiallyidentical with the distribution of blood groups in the entire series ofcases studied by the Board and with an average sampling of the Americanpopulation.
In 21 cases in which plasma hemoglobin levels were obtained at approxi-
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mately the same time that the first urine specimen was voided, the concentrationsof pigment in the two fluids were compared. No evidence of correlationwas found. It was concluded that the threshold of hemoglobin excretionin wounded men must vary over a wide range.
Myoglobin was positively identified in the urine of 19 patients in theseries and these cases were subjected to special scrutiny. As in the caseof hemoglobin, no correlation was found between the concentrations of benzidine-reactingpigment in the plasma and of myoglobin in the urine.
With the exception of clear-cut cases of the crush syndrome, excretionof myoglobin could not be predicted from the nature of the patient`s injuryor its complications. It was rarely seen in wounds of the extremities,even those associated with extensive necrosis of muscle, unless they werecomplicated by clostridial myositis, or, as in two cases, circulation wasre-established after a period of ischemia by a successful arterial anastomosis.It was sometimes very severe in patients with little or no muscle damage.When muscle damage was extensive, the mobilization and excretion of myoglobinappeared to be independent of the development of shock. When there wasinsignificant or no muscle injury, myoglobinuria was rarely found in theabsence of moderate or severe shock.
Two further observations are noteworthy though their significance isnot apparent. Myoglobinuria was frequently massive, hemoglobinuria rarelyso in the absence of injury to the urinary tract. Myoglobinuria and hemoglobinuriaof significant degree frequently occurred in the same patient, suggestinga common but undiscovered mechanism.
CONCLUSIONS
1. Neither the development of shock nor the therapeutic use of multipletransfusions of group O bank blood produced immediate elevation of theplasma "hemoglobin" levels in severely wounded men.
2. The delayed rise in mean plasma "hemoglobin" for the series as awhole in the period from 24 to 96 hours was largely attributable to iso-agglutininsin the O bank blood, since it was absent in a sample of 51 O recipients.
3. Mean plasma "hemoglobin" concentrations were higher in the patientsin whom pigment nephrosis developed than in other wounded men but werestill far below the threshold level at which the normal kidney excreteshemoglobin.
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A depression of the threshold for hemoglobin excretion must be assumed.
4. The lack of correlation between concentrations of benzidine-reactingpigment in the plasma and of hemoglobin or myoglobin in the urine suggeststhat this alteration of threshold was variable.
5. The irregularity with which extensive muscle injury was followedby myoglobinuria indicates that some factor other than necrosis of musclecells is involved. This factor is not shock and appears to be the maintenanceor re-establishment of the circulation in the involved muscles.
6. In a small number of cases severe myoglobinuria developed in theabsence of demonstrable muscle injury. The almost constant presence ofmoderate or severe shock in such cases suggests the possibility of diffuseischemic injury of muscle which is not morphologically recognizable.
7. The fact that severe myoglobinuria and severe hemoglobinuria wereoften observed in the same patient suggests the possibility of a commonmechanism.
