panel discussion — v

PANEL DISCUSSION - V PAUL OWREN, Moderutor

Universi ty Hospital, Oslo, Norway

AGGELER : Effective use of transfusion therapy in hemorrhage disorders requires accurate information regarding the volume of distribution, the time required to equilibrate with extravascular spaces (if such exist), the turnover rate, and the effective hemostatic level for each clotting factor. The larger the apparent volume of distribution and the more rapid the rate of equilibration, the faster the rate of disappearance .from the plasma will be - regardless of the physiologic half-life. Based on transfusion experi- ments in patients with congenital clotting factor deficiencies, the best cur- rent estimates of these parameters are :

TABLE 1

7 1 Volume of distribution

plasma No.

I I volume)

I I Fibrinogen I 2-5

II I Prothrombin I 1.5-2.5

VII Proconvertin 2 -4

Vm Antihemophilic 1 factor

IX P.T.C. 2 -4

X Stuart-Prower 1

XI I P.T.A. I unknown

Minimum Half-tims of Physiologic hemostatic level

from (in hours) (per cent ( i n hours)

disappearace half-life

m d

12 -36 60-144 80-100

22-24 80-123 10-20

12-20

l p - 3 1 / 2 1 - l p - 6 20-25

4 -6 7-10 20-30

4-6 20-30 20-30

40-50 40-50 8-10

unknown I unknown I 20-30

The rate of disappearance of clotting factors from the circulation may be increased by fever, infection, tissue damage, and hemorrhage.

OWREN: Thank you, Dr. Aggeler. Now for the discussion of the many problems that have been raised by these papers this morning. There are many different topics, and we will t ry to cover most of them. We will start with problems related to the transfusion of cadaver blood.

524

Panel Discussion - V 525

SAWYER: Dr. Owren, could I ask you a question? Have you heard of this work being done by a group of doctors in Yugoslavia? I recently received a message from Doctors Naumasovski and Dejanov of the University of Skoda, whom you may know, that they are apparently using catophoretic plasma for transfusion. They report that they are not adding anticoag- ulants to their cadaver blood. As the blood comes out, they separate the cells from the plasma and then run the plasma through some sort of nega- tively charged cone. Dr. Naumasovski indicates that no anticoagulant is necessary after that. The ions added a t the negative pole apparently satis- factorily anticoagulated the plasma. Do you know anything about this work?

OWREN: I am not familiar with this experiment. Are there other questions related to the transfusion of cadaver blood which may be not of too much use in peace time, as i t was suggested, since we had a more easy source of donors in disasters? Also during war time, as Dr. Crosby indi- cated last night, i t would not be suitable a t that time either. Would Dr. Crosby like to comment on this problem of cadaver blood?

CROSBY: Most of the wounds that are responsible for death in combat and disaster situations are due to transection of large vessels : that is most of the killed in action die of hemorrhage. Furthermore the logistical problem of collecting the “donors” and bringing them into the bleeding centers would also rule out the use of cadaver blood. One thing that we know from war experience is that collection of the wounded is an extraordinary difficult problem. We can’t have enough stretcher bearers to do the job as well as we would like to do it, and to divert these stretcher bearers to the collection of dead would not be a reasonable procedure.

OWREN: Thank you Col. Crosby. Cadaver blood is in fact serum with dispersed blood cells. Postmortal coagulation is followed by fibrinolysis and I would think, therefore, that it contains fibrin-split products. I would like to ask Dr. Fletcher’s view on the use of such blood in patients that have been severely injured or that suffer from other conditions associated with high fibrinolytic activity. What happens when more of these split products is infused?

FLETCHER : We have neither used cadaver blood therapeutically nor have we examined samples of such blood prior to transfusion use.

However i t would seem very probable and indeed virtually certain that, as suggested by Dr. Owren, cadaver blood of this type would be devoid of fibrinogen and in lieu of fibrinogen contain fibrinogen proteolysis products. Theoretically the use of such cadaver blood would be contraindicated in serious bleeding or injured patients since its employment would tend to ag- gravate any coagulation defect and to interfere with hemostasis. However those reported results, known to me, have not suggested that this theoretical

Annals New York Academy of Sciences

danger is of great practical importance, but the evidence on this point must be characterized as meager.

OWREN: Does anybody else want to comment upon this problem? The ethical and psychological aspects of cadaver blood transfusion have not been mentioned. Any comments? If not, we will discuss the changes .that occur during storage of blood. Of main interest for hemostasis is the decrease in factor VIII, factor V, and in platelets. Of course these changes have no implications for most of the transfusions that are aiming a t re- placing red cells and a t keeping up the circulating blood volume. In certain conditions of coagulation disturbances, however, these defects would make stored blood unsuitable. This raises the problem of methods for increasing the stability of these factors during storage. We have found the greatest stability for factor VIII and factor V a t pH between 6.5 and 7.0. At pH 7.6 - 8 factor V decreases slowly, and above pH 8.0 it disappears completely in a couple of days.

MEREDITH: Dr. Owren could I ask Col. Crosby a question? Col. Crosby you have been more involved with the logistics of blood supply for wounded men than almost anybody in this room. How hard would it be in a routine civilian situation to go through the mechanics of separating the cells from plasma, to produce fresh frozen plasma, from a certain percentage of blood donors on any given day; and then when you wanted to give the blood back to the patient who needed it, to match the cells and the plasma that had been taken off (and given) through separate needles or separate catheters? How much would this actually increase the cost of the blood in a community?

CROSBY : The cost of collecting a unit of blood and processing it without cross-matching, just making i t available, is about $10.00 in the United States at the present time. It runs from $7.00 to perhaps $11.00 or $12.00 depending upon the locality. The amount of increased expense involved in separating cells from plasma would be attendant on the increased cost of the plastic transfusion equipment because it would be necessary to have a satellite pouch on the bag. Plastic bags a t the present time cost about $1.20. Because of certain difficulties in manufacture, the cost of the bag with a satellite pouch is a little bit more than double. The cost would be increased by about $1.50. This would make it $11.50 instead of $10.00.

MEREDITH: That’s not very much. CROSBY : Well it’s more than 10 per cent of the cost. MEREDITH: I t would mean preserving most of our factors and, to some

degree a t least, would keep down the platelet drop that occurs. How many platelets are there left in fresh frozen plasma if you reinfuse i t say within 10 minutes.

CROSBY : None.


MEREDITH : None? CROSBY: Freezing destroys them. OWREN : One question directed to Dr. Goldstein. What method was used

for AHF and PTC assays in your work? GOLDSTEIN : These were thromboplastin generation tests modified from

the original method that Biggs described for the estimation of AHG and PTC. As a base component we used plasma from a hemophiliac and added an increasing amount of normal plasma to get a curve from which we could read percentages when we used our test plasmas. For PTC we used serum from a patient with PTC deficiency. We have also, in more recent work, used the partial thromboplastin test and obtained approximately the same results.

OWREN : This is a question for Dr. Strumia. STRUMIA: The first question refers to the report that in 35 exchange

transfusions to erythroblastotic newborn, using five-day-old blood, no ab- normal bleeding was noted. I did not intend to infer from this that platelets had survived normally. I made the statement that there was no evidence of bleeding in any of the newborn. Platelet counts were done in some of them; the difficulty here is that there is no opportunity to follow these patients for a sufficiently long period. A drop in platelets occurs, but apparently it is not sufficient to cause any hemorrhagic phenomena. We do not routinely use five-day-old blood, but we use i t if we do not have any fresher material. Even in a newborn subjected to 5 exchange transfusions in 2 days, with blood having a mean storage of 1.7 days, no hemorrhagic phenomena were noted under very close observation. Second question : “Have you made any observation of decrease in platelet count in men or animals subjected to multiple transfusions of stored blood without surgical procedures?’’ No, all of our patients were subjected to surgical procedure and most of them were actively bleeding at the time of transfusion. Also all of the patients studied were subjected to general anesthesia.

OWREN: I would like to comment upon the problem of platelets and hemostasis; it is not only the number of platelets that count, but also their function. This may become particularly important in patients given multiple transfusions. We have observed cases of hemophilia, who after multiple transfusions, developed “Thrombasthenia” with lack of adhesiveness of the platelets associated with a prolonged bleeding time. This may also happen after massive transfusions in surgery and can be detected by doing a bleeding time test. During the previous discussion the bleeding time was largely discarded as a test for assaying hemostasis. In my experience the bleeding-time test is very useful in this respect and ought to be applied routinely also in the surgical patient who starts to bleed. A prolonged bleeding time in the absence of a marked thrombocytopenia indicates changes in the platelet function. The reductions of coagulation factors reported

528 Annals New York Academy of Sciences

would not influence hemostasis or the bleeding time. The defective hemostasis observed must be caused either by platelet disturbance or by an increase in fibrin-split products. We have found that prolongation of the bleeding time parallels a decreased adhesiveness of the platelets. Platelets are not being consumed normally a t the wound surface. This can be demonstrated by Borchgrevink’s technique of counting platelets in consecutive drops from a standardized wound and in venous blood. The difference gives a measure of the consumption of platelets for hemostasis. This difference is abnormaIly low in these patients. The next question is for Dr. Sherry but will be answered by Dr. Fletcher. FLETCHER: There are three questions addressed to me, all deserving of

extended discussion, but since time is running short I hope that brief an- swers will be forgiven. The first question reads “Are fibrinogen inter- mediates, similar to those observed following plasmin or trypsin digestion of fibrinogen and capable of interfering with fibrin polymerization, produced by the action of thrombin on fibrinogen?” The answer to this would be no, since thrombin exerts extremely limited proteolytic actions upon fibrinogen; its action, in this regard, is restricted to the splitting off of peptides A and B and to the formation of fibrin monomer.

The next two questions are related and I shall try to answer them as one. The first asks what practical tests can be used to differentiate various fibrinolytic syndromes, and the second, from Dr. Marjorie Zucker, is of disarming innocence and reads “What is your experience with epsilon aminocaproic caproic acid in non-fibrinolytic bleeding?” Any confident answer to this latter question would imply that diagnostic measures for distinguishing between these various bleeding syndromes possess a speci- ficity and certainly that none who have attended this conference, would be prepared to concede. With this reservation I shall attempt an answer.

In most situations in which the therapeutic efficacy of EACA is well established its action as an inhibitor of plasminogen activation accounts for its hemostatic properties. As an example of its local action I would cite its use in the treatment of excessive hematuria following prostatectomy ; in this defined situation the drug’s action is predictable and sometimes dramatic, while its recognized biochemical properties clearly account for its hemostatic action. There is a second class of patients for whom there is sufficient time to perform a full workup in which the diagnosis of hemorrhage secondary to a pathological plasma proteolytic state may be deter- mined with certainty; the response of these patients to the drug is again related to its action as an inhibitor of plasminogen activation. A classic example would be the hemorrhagic diathesis arising secondarily from carcinoma of the prostate with bone metastases. However in a third class of patients (and I am sure that Dr. Zucker’s question refers to this type of situation) the diagnostic picture, for various reasons, is obscure and


any beneficial clinical actions of EACA are seldom precisely definable as stemming from its recognized biochemical actions though, a t least in my experience, there always remains a valid, if sometimes weak, inference that such might well have been the case.

This third class of patients are predominantly those for whom emer- gency consultation is requested during the course of a cardiac bypass procedure, and in such circumstances the clinical problem is often of the greatest urgency and is often also diagnostically confused. One goes to the operating room and finds, that the patient has been on bypass for an hour or so, that bleeding has recently become severe, and that protamine has been administered a t which point the bleeding has often worsened. The first step should be to assess the gravity of the surgical situation, for very rarely, I would estimate about five times in my personal experience, is there clearly sufficient time to perform any coagulation studies and the difficult decision as to whether EACA treatment should be started is purely a clinical one. When the situation is of extreme gravity I have treated such patients with EACA; in some there has been an excellent response, and laboratory tests have confirmed that each such patient was suffering from pathologic plasma proteolysis. However I would emphasize that such treatment is extremely hazardous for, as Dr. Sherry has stated, fibrinolysis may be due to intravascular coagulation - in which case EACA treatment might be deleterious ; indeed Dr. Gibbon remarked yesterday that he knew of two patients who had experienced massive thrombosis following EACA treatment. However there are rare occasions in which the use of EACA is probably, despite its hazards, life-saving.

Normally the clinical situation is not of this degree of urgency, and we run determinations for plasminogen activator (I1 Wabeled fibrin substrate method) euglobulin lysis time, plasminogen, fibrinogen, one-stage time and thrombin-clotting time ; interpretation of these assays is not always easy (J. Clin. Invest. 1962:41:896), but they are useful and by the time one returns to the operating room these patients for whom the tests are negative are usually bleeding less and normally do well as far as their hemorrhagic diathesis is concerned without treatment other than transfusion. If, however these tests are markedly positive, the clinical situation is usually less satisfactory and EACA therapy may be considered. How- ever, because of the difficulty of determining whether pathological plasma proteolysis is primary or secondary, such therapy is not free of risk even in the presence of positive laboratory tests indicative of pathological “fibrinolysis.” Consequently we use EACA with only great reluctance and only if the clinical situation appears to demand it. Because of the fact that thromboplastic material and activated coagulation products are rapidly cleared from the circulation, the decision to use EACA therapy should be

530 Annals New York Academy of Sciences

postponed as long as is feasible since in this way the risks inherent in its use, in such patients, will be reduced.

It’s not possible, because of the wide variability in the clinical material, to produce any useful statistics on EACA treatment, but we have treated approximately 26 patients with these types of disorders and have declined to treat a much greater number on grounds of insufficient clinical urgency. About one-third of the patients respond in a rather dramatic manner, about one-third respond, and in others EACA administration has had little effect. I would add that in these patients it is difficult to correlate clinical response with laboratory findings, and I believe that this is the point of Dr. Zucker’s question.

There are of course several reasons why there should be a poor correlation between clinical response and the laboratory findings, the most per- tinent of which relate to limitations of specimen sampling. These patients are connected to a large extracorporeal reservoir; they are being trans- fused, and it is therefore difficult to get satisfactory and representative blood samples. Moreover plasma sampling may tell us little concerning fibrinolysis a t the local level or a t the bleeding site itself. I would tenta- tively conclude that the hemostatic actions of EACA are related to its action as an inhibitor of plasminogen activation but would draw attention to the difficulty of proving this hypothesis in patients suffering from complex hemorrhagic syndromes. OWREN : Another question : Is there any evidence that anesthetic agents

are responsible for capillary bleeding and for prolonged bleeding times in surgery? BUNKER: In the studies of effects of a variety of anesthetics on bleed-

ing in the surgical patient that Dr. James Vanderveen conducted along with myself and Dr. Goldstein there were prolonged bleeding times during halothane in a few patients, but these patients did not bleed excessively during subsequent surgery. We simply were not able to interpret the tests, and I think they probably were without any particular significance. As another example of the difficulties in the interpretation of bleeding time measurements I might mention that during hypothermia bleeding time may be indefinite and the patients may bleed for several hours from the skin puncture, and yet these same patients may be operated on a t the same low temperatures without any evidence of increased surgical bleeding.

I would like to make one other comment about halothane. As many of you know this anesthetic has been used specifically in an attempt to decrease surgical bleeding, and one of the advantages that has been attributed to halothane is an accompanying peripheral vasodilation and arterial hypotension. It is hoped that this hypotension will produce the same decrease in surgical bleeding that one may see with the intravenous ganglionic blocking agents and hypotensive spinal anesthesia. If halo-

Panel Discussion - V thane does, in fact, reduce surgical bleeding, i t is probably secondary to vasodilation on the venous side and to an accompanying fall in venous pressure.

Another question reads “Please comment on the possibility of bleeding associated with liver damage following halothane anesthesia.” The recently reported possibility of halothane-induced liver damage appearing in the postoperative period carries with i t the implication of a possible late postoperative bleeding diathesis. The relationship of halothane to postoperative liver necrosis is by no means clear and in any event should not be a consideration in the etiology of bleeding a t the time of surgery.

OWREN: Thank you Dr. Bunker. And the next question is: “Is the original prothrombin time using acetone-dehydrated rabbit brain sensitive to factors VII and X?” I would like to direct this question to Dr. Quick.

QUICK: I am the one who asked it. OWREN: Then I may have to answer. In my experience the acetone

treatment tends to preserve factor X but not factor VII, a t least not to the same degree. The use of such thromboplastin makes the test less sensitive to factor X in the tested plasma. The sensitivity of factor VII is usually good but varies from one preparation to another depending on the technique of preparation. As was shown in my previous presentation, rabbit brain thromboplastin gives higher values than thrombotest because the latter is specifically prepared to reflect reductions in factor X during treatment. Have you any comment Dr. Quick?

QUICK : Yes. The original one-stage prothrombin time test is very sensitive for measuring factor VII because the thromboplastin, acetone-dehydrated rabbit brain, which I insist on using, contains no demonstrable amounts of factors VII and X.

OWREN: I agree with Dr. Quick that his original rabbit brain thromboplastin and also human brain thromboplastin, prepared so as to get rid of blood and serum, is much more sensitive to factor X and consequently much more useful for guiding of anticoagulant therapy than thrombo- plastins that are seriously contaminated. It is impossible to get completely rid of blood and blood derivatives if lungs are used for preparing thromboplastin extracts.

There are two more questions. One for Dr. Spaet. “How do you define the hypercoagulable state?”

SPAET: An attempt to do this would create quite a controversy. The literature on the subject contains operational definitions that reflect tests in local use. The range is all the way from increased precursors to short- ened clotting times to a manifest thrombotic diathesis.

OWREN: This question was also directed to me but I would like to have your comments first and I agree with what you have said. There is no adequate definition of the hypercoagulable state. Some investigators have

Annals New York Academy of Sciences

emphasized the finding of an increased factor VII activity, such as is usually found in late pregnancy. I would like to mention, therefore, that I do not believe that factor VII plays any great role in the reactions that lead to thrombosis. We have seen two patients with complete factor VII deficiency who developed venous thrombosis postoperatively. Thrombosis presumably is first and foremost a problem that concerns platelets and the intrinsic clotting system. We have tried to analyze this problem by study- ing the activity of the intrinsic clotting system in different conditions that are notorious for having an increased thrombosis tendency (such as the postoperative state) : by intravascular hemolysis, by resorption of necrotic tissues, by injection of foreign proteins, etc. There seems to be present a certain pattern of changes in all these conditions: increased activity of factors VIII and V and increased fibrinogen concentration; further, increase in activity of the plasma factor that is lacking in v. Willebrand’s disease and an increased adhesiveness and aggregation tendency of the blood platelets on exposure to very small concentrations of adenosine di- phosphate. But the correlation between one or more of these findings and the thrombotic tendency has still to be demonstrated. After thrombosis has occurred the situation is quite different because secondary changes are then produced. The same is true if intravascular coagulation takes place, because if thrombin is formed i t destroys both factor VIII and factor V probably by causing their activation followed by inactivation.

The next question is directed to me: “DO you relate platelet function more to hemostasis than to thrombosis?” Hemostasis and thrombosis are related phenomena. The hemostatic platelet plug corresponds to the initial white platelet-thrombus formation. Primary hemostasis is largely inde- pendent of the coagulation of plasma. The most fatal part of a thrombus, however, is the red coagulation thrombus because i t so often is the occlud- ing thrombus both in venous and arterial occlusions. The aim of anticoagulant therapy is in fact to preserve platelet plug formation and platelet-thrombus formation but to prevent the red coagulation thrombus. Platelet-thrombus formation can also be prevented by very intensive anti- coagulation which prevents thrombin formation from adsorbed factors at the platelet surface, and which is necessary for viscous metamorphosis, but then hemostasis will also become deficient resulting in a prolonged bleeding time.

Now a question to Dr. Lucas: “Do you believe that successful hypnosis is primarily due to psychological factors or is hypnosis itself a physiological phenomenon?”

LUCAS: I do believe that hypnosis is a physiological phenomenon- that is why we are using it. I would have never used it if I did not think that there was a physiological basis. I think that Pavlov is one who showed that hypnosis has a physiological basis. The other thing I tried to point


out is the psychological aspect of the hypnosis. I think I point this out in my presentation, in my opening remarks. We do not believe that we are successful in affecting hemostasis in the hemophiliac due to hypnosis. But we do believe that hypnosis can be responsible for the initial tranquilizing effect, and that may be due to the influence of hypnotic suggestion on the vascular factors. I think that hypnosis may be working on vascular factors due to two very important principles : direct nervous influence through the autonomic system, or indirect influence through the endocrine system. That is not proven, but we have done extensive work in coagulation time, prothrombin time, thromboplastin-generation test, and have not found any differences in the rate of the coagulation time, or in any other blood tests. But we think that hypnosis has a physiological effect and our main effort is to get a completely relaxed, understanding and cooperative patient. This tranquilizing plus packing of the socket and protection of the extraction areas is responsible for contributing to hemostasis. OWREN : Rasputin seemed to have been successful in the use of hypnosis

for arresting bleeding, and he thereby influenced the political history of Europe.

This was the last question and I would like to thank the members of the panel and also those who have asked the many interesting questions.

panel discussion — v

Documents