546 S.A. MEDICAL JOURNAL

DEXTRAN

A VALUABLE PLASMA VOLUME EXPANDER

5 July 1952

ANTHONY J. LEONSINs, M.B. (RAND), F.R.F.P.S. (GLAs.), F.R.C.S. (Eo.)Department of Surgery, University of the Witwatersrand Medical School and Johannesburg General Hospital

Dextran has been medical news for about 9 years, but itis only in the past year or two that it has made any head-way in South Africa. This has been largely due to theestablishment of a large production plant (African-Dextran) in Edenvale, close to Johannesburg. Up to thepresent over 120 papers have been published on Dextran.

The School of Carbohydrate Chemistry in the Birming-ham University, during the late 1930's, was activelyengaged in the study of bacterial and other polysaccha-rides of microbiological origin. The work was under thegeneral direction of the late Prof. Sir Norman Haworth.Many polysaccharides were examined, but the Dextrans,produced by the bacteria of the Leuconostoc genus cameunder particular study by Stacey and his colleagues. In1937 Stacey outlined the possibility of using non-antigenicpolysaccharides in the animal body, by simulating thecolloid osmotic behaviour of plasma proteins in thevascular system. A further advantage was that theseDextrans were resistant to enzymatic breakdown by thebody amylases. In 1943 Gronwall and Ingelman 7 ofSweden, independently of British workers, suggested theuse of Dextran as a plasma substitute. Subsequent suc-cessful clinical trials established its value and to-dayhuman plasma is no longer diligently sought after for usein many clinical conditions, as Dextran has fulfilled mostof the requirements. Important factors in this practiceare the question of readier availability and greatereconomy. It was only in 1947 onwards that extensiveclinical evaluation took place in Great Britain, after thestringent tests of the Medical Research Council had beensatisfied. At present many thousands of half-litreDextran 6% units are distributed to United KingdomHospitals through the British Ministry of Health and theexcellently organized Blood Transfusion Services.

There is no doubt that Dextran has proved of distinctbenefit in many clinical conditions. In our time anotherwar is a strong possibility and, as stressed by Americanand European authorities, there is an ever-threatening useof atomic weapons. Overwhelming atomic destructionmight well affect any industrial and urbanized area in thisconstantly shrinking world of conflict. As the Witwaters-rand is no longer exempt from an enemy's flying bases,our South African military authorities may well take heedof such warnings. Not only gross physical trauma, butthe insiduous withering effects of atomic irradiation canaffect literally thousands of people. The Blood and PlasmaTransfusion Services available in South Africa could neverhope to cope with one such devastating calamity. InJohannesburg, despite a first-class service, it could easilybe knocked out of commission; therefore for that reason,and many others, it behoves our medical public to be morefamiliar with the use of another valuable resuscitativesolution.

In 1946 Bohmansson and his colleagues 1 suggestedcriteria for a satisfactory plasma substitute, as follows:

1. The product must be pure and atoxic.2. It should be stable and should present no problems of

long storage and transportation.3. It should have the same colloid osmotic pressure as

plasma and the same water-binding power as the latter.4. It should have the same therapeutic effect on shock as

blood and plasma.5. It should give rise to no reactions or morbid changes

when introduced into the blood (i.e. non-pyrogenic, non-antigenic, non-thrombotic, non-allergenic).

6. It should cause no local reactions in the form of throm-bosis or tissue necrosis at the site of injections.

7. It should be either consumed or excreted by the body andnot be deposited as a foreign substance.

Bull et aI.,2 a formidable team of British workersassociated with Bums Units and Blood TransfusionResearch Units, in a most valuable paper published in1949, showed that Dextran was the solution that couldfulfill most of these requirements. They also added that'the composition from batch to batch should be constant,within narrow and definable limits '.

BASIC PHYSIOLOGY

As we know, serum albumin with a molecular weight ofabout 70,000 constitutes over 50% of human plasmaprotein. Other constituents are globulin (12 %) with amolecular weight of about 160,000, and a small fraction(4%) consisting of fibrinogen with a molecular weight ofabout 400,000. Since albumin has the smallest moleculeit possesses the greatest diffusibility and exerts the highestosmotic pressure in the plasma. The normal kidneys donot excrete molecules greater than 70,000. In traumaticshock there is a marked loss of plasma fluid and albumininto the tissue spaces and injured areas, thus causing areduced plasma circulating volume and, as a result, poorvenous return, reduced cardiac output and a fall in bloodpressure. In bums and crush injuries, even though notassociated with obvious haemorrhage, there is a loss ofblood cells as well as a great deal of plasma; hence it isimportant to use whole blood as well as a plasma volumeexpander. In untreated high intestinal obstruction, invisceral perforations, during operations, and in adrenalinsufficiency, the plasma volume is similarly reduced withresultant peripheral circulatory failure, and possible tissueanoxia. Since World War I various plasma volumeexpanders have been used. The employment of suchmacromolecular colloidal substances prevents plasma fluidfrom readily escaping into the interstitial tissue spaces.Stormont 20 reviews the subject fairly well.

PLASMA VOLUME EXPANDERS

Solutions of saline or dextrose are too rapidly lost fromthe circulation to provide more than an evanescent supportof blood pressure and volume. If electrolyte solutions areused, the increase and accumulation of tissue fluid fromthe impaired vascular system may become an embarrass-ment. If there is pre-existing anaemia or haemorrhage,dangerous haemodilution may occur.

5 Julie 1952 S.A. TYDSKRIF VIR GENEESKU DE 547

.'

Acacia 6% solution has suitable colloidal characteristicsbut it actually causes a diminution of the plasma proteins,which is greater than can be accounted for by thediluting effect. This substance was used by Bayliss inWorld War I, but it was not popular. Most of the acaciaescaped from the blood within 7-10 days, but little wasexcreted by the kidneys. The greater portion was storedin the liver and other organs. There is evidence that itmay interfere with hepatic function and delay theregeneration of serum protein. Acacia and other gumcarbohydrates, such as algin and laminarin, both derivedfrom seaweed, are potential allergens.

Despeciated bovine serum, from _which most of theglobulin fraction is precipitated and the agglutinins andhemolysins destroyed by controlled heating, has been usedintravenously in man without adverse reactions. Thedespeciated serum has a protein content, chiefly albuminof about 5 gm. per 100 C.c. It is stable at room tempera-ture for storage up to 6 months. It is expensive to produceand difficult to prevent antibody reactions.

Gelatin, derived from fish, beef bone and pig skin, hasa suitable osmotic effect and is rapidly excreted by thekidneys in 24-48 hours. It tends to depress serum albuminlevels and does produce pseudo-agglutination of the redcells, so that it may interfere with blood typing unless thisis performed before its administration. If there issuspected renal impairment it should not be used. Aspecially refined beef bone collagen (P-20) was developedin the United States of America during World War 11, viz.6% Knox gelatine solution. This can actually produce apositive nitrogen balance, but its big disadvantage is thatit is a gel at room temperature and must therefore be keptwarm during administration.

Polyvinylpyrrolidone is a synthetic polymer derived fromacetylene and was introduced by the Germans duringWorld War IT, under the trade name of Periston-Bayer. Itis also known as P.V.P. and Plasmosan (May and Baker).Its average molecular weight is 80,000. A 3.5% solutionin saline was found to be effective in maintaining bloodpressure. Like pectin, a plant colloid, it was unstable inalkaline media and only half was excreted by the kidneys,the remainder being deposited in the bOOy especially thespleen. Recent experiments suggest that it may take aslong as 5 years before P.V.P. can be totally excreted fromthe body. It shortens coagulation time by reducingplatelets and it may also increase red cell sedimentationrate.

Dextran is one of the nuisances in the sugar refineriestowards the end of the season when the factory pipesbecome clogged with its ropy and sticky formation. Itwas Pasteur, in 1861, who attributed the cause of thisslimy fermentation to microbial action. In 1904 vonTreghen gave the first adequate description of one of theseincidental contaminant organisms naming it Leuconostacmesenteroides.19 Many molecules of this kind areextremely large, with molecular weight up to two or threemillion. Their structure consists of branched polyglucosechains which, under the electron microscope, resemble adead twig from a tree.H In a Dextran factory asolution of ordinary cane sugar with mineral salts andyeast is inoculated with a culture of Leuconostac mesen-teroides.17,24 During the fermentation Dextran is pro-duced; it consists of some 200 to 500 glucose molecules

linked in long chains. Growth of this crude culture isstopped after 36 hours in order to prevent heaviermolecular formation. The next step is to depolymerizethe Dextran, i.e. the large molecules are broken down byvarious patented chemical processes. In these reactionsacetone is used to purify the Dextran until an averagemolecular weight of 80,000 is obtained as judged by specialviscosity measurements. Eighty per cent of African-Dextran (Intradex) has a molecular range of 80,000, about15% is below 60,000 and about 5% is above 80,000. Thisrange exerts a colloidal osmotic pressure 1t times that ofplasma. For every 1 gm. of Dextran which remains inthe circulation 23 C.c. of water combine with it. In manthe greatest excretion of Dextran occurs in the first 24hours and that is approximately 20% of the total with anaverage maximum molecular weight of 40,000. In thenext 24 hours another 10% is excreted. There is factualevidence that osmotic pressure is maintained at high levelsfor at least 36 hours. Only traces of Dextran are stilldetectable 10 days after infusion with the usual 6%solution in normal saline. The larger molecules ofDextran are broken down with eventual metabolism of theresultant glucose. After very extensive and controlledanimal experimentation and clinical trials, there is noproven evidence of prolonged storage or of serious per-manent damage as a result of the administration ofDextran.6, 10 In the first 48 hours, because of themaximum excretion of Dextran, the urine specific gravitymay rise to 1,040 or more. In a meeting of the AmericanMedical Association 1951, Gutteridge 9 reported that'Dextran has given satisfactory and sometimes dramaticresults. In the treatment of shock and in the first-aidtreatment of haemorrhage it has been shown to cause asustained increase in cardiac output and an increasedvenous pressure. There is no significant change inglomerular filtration rate. Impaired kidney function is nota contra-indication, and in normal subjects there is nodiuresis. There is no clinical evidence that it damages theliver, and liver disease is not aggravated by it. Dextranis the product which will be stock-piled by the ArmedForces in the U.S.A.'.25.26

Recently, a criticism was made against all macromole-cular substances used as plasma volume expanders becauseof the difficulties a blood transfusion service may have inefficiently cross-matching recipients' blood that hadreceived prior infusions of Macrodex, Dextran, etc. It isa fact that there is a temporary or transient increased redcell rouleaux formation after Dextran infusions, but thisis not weak agglutination. It is not a serious obstaclefor compatible blood transfusions and should be of noclinical significance; nevertheless, mention must be madethat Dextran has been used in order to enable extra careto be made in cross-matching. It is the larger moleculesof Dextran that are responsible for increasing erythrocytesedimentation rate. Th more homogeneous the Dextranfraction is in respect of molecular weight, the smaller theproblem is. However, it is a wise and necessary precautionto take a sample of blood as a measure preliminary to anyemergency infusion of Dextran in order to perform a directmatching test in the event of whole blood being necessarylater on. The dubious advantage of providing extra proteinnutrition in plasma infusions may be discounted in thecase of adults, but may be of more importance in children,

I

548 S.A. MEDICAL JOURNAL 5 July 1952

in whom nutritional balance may be more difficult tocorrect by mouth. Whole blood, because of its additionalhaemoglobin protein content, is a richer source of protein.Most adults are well able to eat a nutritious diet within48 hours of an acute surgical emergency. The dailyprotein requirement of the average patient is about 90 gm.,i.e. the equivalent utilizable protein in 1 lb. of uncookedmeat costing 3s. Five pints of milk, also costing 3s.,will provide more than 100 gm. of protein besides a totalof 1,800 calories. For protein to be utilized by the bodyefficiently, a basic calorie allowance of about 1,500 mustfirst be available, otherwise the plasma proteins will becatabolized for basic energy requirements and thus wasted.One pint of plasma provides about 30 gm. of protein at thecost of 6. Imagine the cost of treating some burns caseswhich may well require more than 4 or 5 pints of plasmaa day for 3 or 4 days. As Dextran costs 308. a pint, it isof considerable economic importance. 'Dextran does notlower the plasma protein concentration to a degreesufficient to affect the coagulability of the blood, woundhealing, resistance to infection, or formation of immunebodies.' 16 In the writer's opinion there is no valid reasonwhy Dextran 3% should not be combined with certainessential amino acids and minimum balanced electrolytesin order to provide a more useful solution. An importantproviso in modern surgical handling is the deliberateavoidance of using normal saline solutions duringanaesthesia and in the first 48 hours post-operative period,unless to replace intestinal fluid loss.3, 4, 14 Plasma is richin saline and unless electrolytes are being lost it shouldbe avoided. Dextran saline-free and whole blood arepreferable in nearly all surgical requirements. Dr. M.Shapiro of the Johannesburg Blood Transfusion Servicestates: 'There is only one firm indication for using plasma,and that is in the control of shock. . .. During the past7 years the demand for plasma has definitely decreased.Just after the war the ratio was 1 plasma unit to 1 bloodunit but in 1951 the demand was 1 plasma to every 7 ofwhole blood. In most transfusion services all over theworld there are 5 frank haemolytic reactions in every 1,000transfusions. Most of these 5 reactors result in fatalities.In Johannesburg there is only one serious reaction in20,000 administrations.' Dr. M. Shapiro is over-cautiousregarding the free use of Dextran, but it was pointed outthat Dextran saline-free was of the greatest value in mostoperative cases where there was no serious blood loss andwhere formerly plasma had to be used. The saline contentof a pint of plasma is in the region of 6-8 gm. of sodiumchloride, besides an extra 1.5 gm. of sodium citrate usedin the pint collection bottle. This must be of importanceto surgeons and physicians who are trying to avoid theuse of excessive sodium ions.

LundY,12,13 chief anaesthesiologist in the Mayo Clinic,writing on new replacement or oncotic fluids, makesspecial mention of Dextran. As.he has used it in morethan 2,000 operations he speaks with authority. In theyear 1949, 5 lives were definitely saved by administeringDextran after considerable blood transfusion had provedineffective. In 1950, another 6 lives were similarly saved.Lundy never had to use more than a litre at any operationand he considers it would be a handicap in controllingsurgical shock if Dextran were not available. In theroutine methods of anaesthesia he does not permit the

systolic pressure to fall below 80 mm. Hg without activemeasures to combat it NaturallY, if there is more than1-2 pints blood loss, whole blood replacement is essential.In haemorrhage the error has been made of administeringtoo much dextrose-saline, plasma or Dextran and thuscausing a serious haemodilution. This results in insuffi-cient oxygenation of vital tissues and, if maintained longenough, will cause fatalaties unless red cells are rapidlyintroduced into the circulation so as to maintain adequatecerebral circulation.

Extensive deep burns, particularly if over 20% in anadult or 10% in children, present serious therapeuticproblems. Rosenqvi~ IS, 16 uses 500 C.c. of blood in addi-tion to every 1,000 to 1,500 C.c. of Dextran alreadyadministered. The addition of whole blood permits a morerapid and sounder healing of all burnt tissues as well asensuring a greater percentage of success with skin grafts.The rule in bums is to provide at least 100 C.c. of oncoticfluid for everyone degree of burnt area, or a daily 1-3 c.c.per kg. body weight multiplied by the percentage figure ofthe area burnt.

In the toxemias of pregnancy, Vara 22 points out thatproteinuria, oliguria, hypertension, and oedema are typicalsymptoms. Acute protein deficiency may be associatedwith a shock-like state; in the eclamptic patient thehaematocrit or packed cell volume is high. In 1947Golden and Fraser 5 used concentrated plasma to reducecerebral oedema and ease the eclamptic convulsions, butbecause plasma contains a considerable amount of sodiumchloride, this concentration of electrolyte in itself wouldcause interstitial fluid retention. Hence Vara decided toemploy Macrodex, i.e. Dextran 10% saline-free, in a seriesof 21 cases. He was strikingly successful in that the urineoutput was increased, the high blood pressure fell, serumproteins were increased and the oedema subsided.Macrodex concentration of the blood fell sharply and nonewas traceable on the third day after administration.

In nephrotic oedema Wallenius 23 points out that theintense hypoproteinaemia and imbalanced electrolytescause the massive oedema and lowered osmotic pressurein the plasma. The hypoproteinaemia may be due to aleakage in the tissues. Administration of 10% Dextranin saline stimulated profuse diuresis, disappearance ofoedema and lessening of ascites. There was no significanteffect on the serum proteins. In these patients Dextran wasexcreted more slowly than in other patients.

In the past 15 months in South Africa about 15,000units of Dextran have been used. In the JohannesburgGroup of the General Hospital nearly 2,000 units ofDextran were used in 1951. In our surgical wards wehave used Dextran (Bengers and the African-Dextran,Intradex) in a variety of conditions during the past year,and we have never had cause to regret its administration.It has been employed in any condition of shock, multipletraumata, compound fractures, post-operatively, aftergastrectomies, hypertension, small bowel resections; inhaemorrhage, while awaiting whole blood; in burns, pul-monary oedema and jaundice cases. At present, with theassistance of Drs. S. B. Griffiths and C. J. Anderson ofthe South African Institute for Medical Research, we areconducting various excretion tests and serum Dextraninvestigations in order to compare our findings with thoseoverseas.

5 Julie 1952 S.A. TYDSKRIF VIR GENEESKUNDE xiii

This famous blood-plasma substitute,with or without Sodium Chloride isavailable in unlimited quantities from

SELECTED PHARMACEUTICALS (PTY.) LTD.SELPHARM HOUSE' 81 DE VILLlERS STREET' JOHANNESBURG

P.O. Box ~5785 Phone 23-2371/2/3' Telegrams: Selpharm

Farsighted practitioners and hos-pitals keep a small stock ofIntradex. It is stable indefinitelyat all temperatures and does nothave to be refrigerated.

2. WD.I. TOLlDlATmIn a comparative study,2' Terramycin wushown to have the lowest incidence ofside reactions in a series of young patientstreated for primary atypical pneumonia.

I. PROMPTLY IEFflECTIYKIn one series of 20 young patients with bacterialpneumonias, Terramycin therapy produced"unevenl/ul recoveries with slriJcinBclinical improvement within 48 hours.GIld often within 24 hours."!

XIV S.A. MEDICAL JOURNAL

~~~ ~0 Terralllycin

~-'a

~~

~".-~~

5 July 1952

Di3tribut

5 Julie 1952 S.A. TYDSKRIF VIR GENEESKUNDE 549

SUMMARYI. A historical survey of Dextran is given.2. Requirements of a satisfactory plasma volume

expander are stated. .3. The basic physiology and comparison of various sub-

stitutes already used, are discussed.4. The manufacture of Dextran and its essential

chemistry is described.5. Comparison is made with plasma and possible elec-

trolyte disturbances are noted.6. The clinical uses and important effects in restoring

adequate circulating plasma volume, increasing venousreturn and blood pressure, reduction of oedema, andalleviation of pregnancy oedemas are mentioned.I wish to thank Mr. A. Lee McGregor for his interest in thiswork, and also to express my gratitude to Mr. Arthur R.Lockwood of Dextran Ltd., Aycliffe, England, for hisstimulation.

REFERENCES1. Bohmansson, G. et al. (1946): Acta Chir. Scand., 94, 149.2. Bull, J. P. et al. (1949): Lancet, 1, 134.3. Coller, F. A. et al. (1944): Ann. Surg., 119, 533.4. Coller, F. A. et al. (1945): Ann. Surg., 122, 663.5. Golden, A. and Fraser, G. (1947): Amer. J. Obstet Gynec.,

54, 523.

6. Goldenberg, M. et al. (1947): Amer. J. Path., p. 939.7. Gronwall, A. and Ingelman, B. (1944): Acta Physiol.

Scand., 7, 97.8. Gronwall, A. and Ingelman, B. (1945): Acta Physiol.

Scand., 9, 1.9. Gutteridge, N. M. (1951): Lancet, 2, 31.

10. Ingelrnan, B. (1949): Upsala Llikareforenings Forhand-lingar, 54, 107.

11. Ingelman, B. and Siegbahn, K. (1944): Nature, 154, 237.12. Lundy, J. S. (1951): Minnesota Med., 34, 21.13. Lundy, J. S. (1951): Northwest Med., 50, 341.14. Moyer, C. A. (1952): Fluid Balance, pp. 149, 159.

Chicago: Year Book Publishers Inc.15. Rosenqv!st, H. (1947): Acta Chir. Scand., 95, Supp., 124, 1.16. RosenqVlst, H. and Thorsen, G. (1951): Arch Surg., 62,

524.17. Samassa, M. G. (1952): Personal communication.18. Shapiro, M. (1952): Personal communication.19. Stacey, M. and Ricketts, C. R. (1951): Fortschir. Chem.

Org. Natures., 8, 28.20. Stormont, R. T. (1951): J. Amer. Med. Assoc., 147, 658.21. Thorsen, G. and Hint, H. (1950): Acta Chir. Scand., Supp.,

154.22. Vara, P. (1950): Acta Obstet. Gynec. Scand., 30, Supp.,

6,30.23. Wallenius, G. (1950): Scandinav. J. Clin. Lab. Invest, 2,

228.24. General Article (1951): Brit. Med. J., 2, 603.25. Editorial (1951): Brit. Med. J., 2, 591.26. Report (1951): J. Amer. Med. Assoc., 147, 1658.

I

'iI THE MANUFACTURE OF DEXTRAN

M. G. SAMASSA, D.Se. (PADUA), EC.S., M.S.A.CH.I.*African Dextran Laboratories, EdenvaIe

,

Chemically, Dextran is defined as a colloidal bacterialpolysaccharide composed of glucose units.8

A few strains of cocci have the power of splitting mole-cules of sucrose (a disaccharide composed of one moleculeof glucose and one molecule of fructose) and synthesizingfrom the glucose thus obtained a water-soluble gum-likeDextran.

Different strains of micro-organisms produce Dextransdiffering one from another only in some physical proper-ties, such as retrogradation to water insoluble form, crosslinkages, degree of branching.5 ,10

The polyglucose we call Dextran contains a high pro-portion of similar units having oc-D-glucopyranose unitsmainly linked through the I and 6 position.1

This structure has been determined chemically bydifferent investigators in 3 different countries 2, 6, 7 andpartially confirmed by Ingleman and Siegbahn' withelectron-micrographs and ultra-centrifuge measurements.3

Very roughly, the average chain of Dextran, whenadjusted for transfusion purposes, varies between 200 and500 glucose units, as has been indicated by the methylationtechnique and osmotic pressure method.9

PHARMACOLOGICAL ASPECTS

Dextran is manufactured in this country by AfricanDextran (proprietary) Limited, and sold in approximately500 c.c. bottles of 6% colloidal solution in water or in

* Chief Chemist.

isotonic saline, subject to satisfactory results from 16pharmacological, bacteriological, chemical and physico-chemical tests carried out by our laboratories on eachsingle batch.

To further satisfy the medical profession, an acutetoxicity test on white mice is carried out, i.e. by nearlydoubling their blood volume by injecting a requisiteamount of 6% Dextran solution through the tail vein.

In order to detect protein through anaphylactic pheno-mena, we use guinea-pigs injected intraperitoneally (some-times using the isolated ileum with the Shulz-Daletechnique) on 3 occasions at 2-day intervals.

The antigenicity test consists of injecting Dextran intothe marginal ear vein of rabbits, without preliminaryreduction of their blood volume, on 9 occasions, at 2- to3-day intervals, and then carrying out a ring and precipitintest 14 days later.

0.5 c.c. of Dextran is introduced intradermally in a flankof a guinea pig and any cutaneous reaction is noted in theskin surrounding the bleb.

The pyrogenicity test is carried out on Himalayan rabbitsinjected intravenously with 20 c.c./kg. body weight ofDextran and their temperature recorded every 15 minutesfor 2 hours before the injection and during the 4 hoursfollowing the injection. The maximal permissible rise oftemperature in each rabbit is 0.6C. (National Institutefor Medical Research, Hampstead).

Eventually a renal excretion test is carried out in orderto measure the percentage of glucose and Dextran excreted

I'