Dr . p

nv

rDco

In

find e m ry o£

f ~ t out that ti

t te. r with othe :r con aid r tion that I b

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in thor c1c sur ery th t w to follow but on· mp

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rc

ence' d

Dr. Owen H. W angensteen .. z - ,. ugust 6. 1954

Thus we et up our goals a fol ow : r- simp ~ m tbod which would a low un­hurried ur ery in the b ood-fr e heart under dir ct vision ~nd wo d be afe. Work. b g n ~ t the tiln that Doc:t r H tnmer trom w in the .:tboratory with .m , Our !ir t experim nt were with the Sirak.. ump which bad been obtain d !rom Dr. Sirak at Ohio 'ta.t • e : oon disc .rd d this pump bee u of it ineff ctivene

Next we made some ob · rvation u ing n excised cow's h art as th pump nd xtern l pres u · to compre the ventrict.e which in tul"n activ t d the b ood. .d .. ...

though thi method wa quite p .rimitiv • it w s th first ·pp ie tion .of the principle which we r. etu~ned to later of b· ving ingle pwnp with two ci1 .. cuit to pump qu~l

mount abnu , · eously. N xt. we· b an work on the :ana ca.v l occ-lusion expe.-iment to deter min . the toie ance of the h a t. In th ae ·I w iated 'by Hammerstrom and th n by Sp l 1nan and Cohen when the former t ft. ..,t r print of this work is «ached. The studie · were the fir t ignifi.cant tep·s in th evelopm nt of the pr .ent me od.

though a numbe~ of author h d inv · ti ated th tole nee of the he rt to ven eav 1 occlu ion .(Sauer'brucb 1 . 7, on Hdl <:k 14 19 7, c~ r e l 191 . , Cutler 192.4, and m ny others) th re was · urpri. ing di ag ·eemen.t about the to r ·nee of the h art d other ital organa to thie 'procedure. In tb cour of our own experiment . it b came ob­

viou that thi di g.reement depended upon whethe the azygo v ~ wa allow. d to drain into th heart or not a.urmg the p riod of oth :t•wis cotnpJ.ete ven.a. cay 1 occ!u-

ion. This fact had b en empha ized by 1~.ndre eon · nd Wat onl. It occurred to me th t this observation was a tremendousl y important point in rnuch c:~.s Gi bon, Crawford. Denni and others had aH teadf tly maintained th" t the 1nini a.l mount ol blood that could b u ed to euppo t an animal. durin c rdi c by ... p · ss wa the full norm l or b sal c.ardi c: output which i bau 160 cc/kg. body weight/minute. It . eem d impoe ib.t.e to me that the azygos vei coul c rry nywhel"e n.e r th t mount of b!ood ao we began etudie to measur directly th r ount of blo d that flow ~through the zy os vein und r condition of ca.va1 occ u ion. Thes tudi.e are outl ined in the att. ch d reprint en~tl d "~. Quantitative Study of th ' .aygos Factor' During Ven Ca11al Oec tu ion in the Dog' • The e studies indicated that anun · l .re ularly would urvive on ._half hour of cornpl te occlueion of th b-:.Itn:ior ven" cav .. t the he rt and compl te occ.u.eion of the up rior vena cava. just c h ad to th azygo v in eo that the animals w re m~ in· tain d entirely on the .mouat of blood c pab e of nterin the heart,th ough th ir azygoa vein.

urther we tn sur d th mount of blood dir c:t y and found it to be e, s than ne-t nth of the o-caH d ba al or sting c rdiac: ou ut or 8 to 14 cc/kg. body

weight/ minut · • .~ t the time, w re ized that this w a v ry significant :f'inding in much a it im nediately m d po ibl much Silt;lpler methodS of cardiac by-p

C r fu1 phy iologic studie were then undertaken to det rmin what comp nsa ... tory adju trn nt took place in the e animal to a low them. to u.rvive uch £ ntastic r eduction in their blood flow without a.ppa ent harm. Som tni ht wei que tion how th ti au s and myoca.rdiun1 of the nima or pa.ti nt c n b w 11 oxy enated when the rate of y t mic perfusion i. o sub tantially duced. de u.ate oxyg nation with' a

•,

Dr. Owen H. W ngeneteen .... 3 .. .. ll.ugust 6, 1954

educ drat of perfusion i not · p· radox but wa ea i y unde tand be fro111 the know! dg of the v J.uable compen atory facto which occur in these · nima and which h v be n discussed in th enclo ed reprints,

Two of the e eompen atory f ctor re worthy of etnpha is bee u e they pr ... viou ly ·have b en entirety v rlooke •

·rh r a on tb t the myoc rdiu.rn i ble to remain weh oxygenated and thu to with nd direc·t urgi.ca! trauma o euperb.i.y is the Jtp rimenta.i.ly demonstrat d fact th t once tbe heart is re · i ved of it pumping _duti (by the mechanic 1 pu p} it re­quires on y a trickle of cor on y blood :flow in ord r to remain w J.l oxygenated be ... c use it i doin p1· ctic· ly no ~ork and th refore, it oxygen consumption is dra-m tic ly reduc d . The p rfusion of mueb .l r · ount of blood to th heart during car iac by·p , a. ha. be n cu tomary, s v no u efu purpo e and ie actua.ily detrimental bee us when the heart is op n d under uch conditione the co:.ron. ry blood o s m y be ppa ing.

noth r of the e important compen ating mech ism w s the gr · ter efficiency o! the ti sues in xt1·acti the blood cont~ ined oxyg n so th t th co- fficient of oxygen utiliz· tion was incr aeed. ~~ r x mpl , whi venou blood nor1nally r turns to the lunge stil c:ontainin 70 pe cent or more of it oxygen· in tb e animal with reduced · lood flow, this venou b ood 1•eturning to he lungs often con ined ie than l S p r c:ent .of it original & nount of oxygen. Thi v nou de turatio~ wh n· eoup!ed with tLn ei£ici nt o;(ygen tor ucb a rovid d by norm l lung ti sue was va!uable co111pen a-

. tory m eh nism a lowin a iven volume o£ b ood to furni h to the tissues 20 to 3<J· · r c · nt more 'JC.Y n ,. Ven~u d aturatlon nd r the condition doe not indic te

a tat of hypoxia in th tis ue a h b n s t d by Gibbon d D nni •

I

Im edi te y, fun am ntal concept b d ch n d.. Thi wa the finding that w h d en· se rching for tha wou d permit simp ific tion of thi whole roblem o£ by-p 1 g the h rt. o:r it wa at one bviou th t if dog could survive long period .... t rm l body temperatur with no disc n.ab!. il · .ffect upon a blood flow only 1

one-t nth f wh t previou y h d e n thou ht to b the l'ninimu:tn, then the am was tU ely tru for human and important itt.apU.fic tiona of method could b undertaken

t once.

It i difficult to ove •empha i~ the importance of these azygo flow tudiee to tb d velopment f im le m thod fo tot cardiac by-pass. Heretolor , it had been m intain d by Gibbon. D nni , Dodri , Hel.t worth nd c1pparently g n rally aceepted by 1 other that th minin1urn mount of blood nee ry for the safe maintenance of the body during c rdia.c by-p s w l ~.~v ec/ g. body w i ht/minu.t r ten time the azygo ·flow.

In th· me· nt.ime other tudiea h d been in progre s. Doctor Cohen tried direct introduction of oxy n into the blood tream by using a '" •tting ag nt d.nd u. very !in (Seitz) filter. Thi method had a number of dr wb ck and we di carded it. altbou.gh we h v ecently returned to thi ide an~ Doctox.· D l is now working on it. The gr at dv tage o this method of oxy enation i it simpl i city .

en H. Wangensteen .. 4 - .. ugu t , 195

N xt we rn de · ome ob e:rvation of the trial well and ven cav occ ion which a low d ur ry m th tri und r ir ct vi ion. This work h not. be n b-li h d ·formally but 18 cont ined in discussion th Journal. of Thor cic Sur ery (Z6:572-S7 , 1953) enti ed 1101 cue ion of rim nta. Clo u.re of tri· l Septal D -I ct "

It much

ece

W then fo th pump that h d y

i 1u t,;m ou ly nd wh t imi to this in u

lo

en u un ti u tooxyg n cu ar y w rthy f mpha i w lun n n ly, its ability to filt r out p rticul to b xt m lY import t. T fac: • It i th fhming o b ood o r such r api tory xchange, but f ci itat th tr p in th. ombi . Bee au th biood compon nta w r t r

"ffic: ti due to h pa.:rin . at o th diltic but to heparin ~ r not du to h p in · t .. 1. b t r with the lorrn tion: of fibrinolytic n ym • This o Ci rm n hy io og· t, Do h r- in 1877 ·

ci l y "tl

or ny tim d th t of

r •

.t noth · r important inding of the e xperitn n tudles utilizin putnp nd an utog ou tob th oxyg nat d mon tr tion that v ntricu ar eptal d {o;ct

cot1ld c t d an clo d un r ir c: t vi ion with utu Mithout conductio ~ diffic 1

ong th myoe rdium wa well oxyg n· t t norm i t mp r tur • e .. rienc d no conduction difficult! wh t o ver in p rforming numerou ventrieui r · i tomia with th c e tion n cio ur £ v n ·ric a s pt l d f ct • Tbi f cour e

ry to mo t of th publi bed informati n upon t . c· di c: con uction syatem s d upon ob v tion comp•ic t d by ypo"i or by reduc d body mper-

tur • agr with th Glon et vid nc whic indic te th ' , m y, d do

Dr. Ow n H. W ng net en ... 5 - ugu t 6, 954

do not b v ·· ino trial no - · n · trioventric ar node, or a Bundl of His, thu th a tructure could h ve no functi nal impor nee to th c rdi c: ur on.

h ut g nou 1 u

t to v t o dr w o what de 1c

on a th w hi h incid nc of f p conduction

nd m bo ic chan e during utog nou th y os f:~.ow principle _re

in phy io o ica! and met· b

ctu y benefici u J.y

Then

ry f ou,.. m pump w

a

ibi ity of di p r oportion id nt it r the

e ext ·em y £ icie t, af ,

urg ry to b pe form d in an Wlhurried m nn r an trial .

tho h w wer ot £ mil i r with th p r vi u it r tur t th t ti ince no d th r ports f th £ lowin ·nv · ator who had :r port d e tudi s uti izin c ·o c:ircul. tion for intr c~ rdi c: ur ery.

et to ork b od flow.

· t ch d

'w h v e im n 1

II •

K r 3 ( 951), Soutbw rtb utiliz d c:ro · cir u ::tti n r p ar 1 ignificant du to th i . the fact that th y did not us p :.:ienc · d bock and death tt mpt d to bunt muc.lt

- 6 .. .,.ugust 6, 1954

eircu ation might e us f ort of um MegibowZ

ir of ani s, but th y p-, n m 1 y, p p to con rol

1 e no mention o ration J.e, oo flow wlth ood z u t th

1d Pi rce ( 1952), nd enn and S w S (1 9 :~3), 1

tia o o pl te cardiae y -pas ,. ut thei tudie .tnany technic 1 diffic ti d ubtl e in part due to

o· cont o th lnte r cba.nge of b .. o d and thu e ... l l a.ding into the oth · r. They a l o

a· r y.

· ndr n d 'Vatson6 ( 1 s· ) h ve pr d taiLe physiOlOgic of eir xperiment Uti l. izing e r os cir cu ti n method · c rdi c y-pa s. They

ipha i the i.::npo:t:t· of a pump to cont o in· rchange b tw tl donor and r · ci ient; ewi , y av d the I ignific ·nee of th ·ygo .facto'r. In many f the ·:a: e~pe im nts, y exper ienced fficu ty in c:bievin · dequ te

1 tu n .fr om their r cipi nt dog d ·th y th r e!or c nc ud d th t thi wa . to xt tan inh ren imit · tiori of th m th d du to the pooLing o£ th blood in th ~ nt• _ capillary b d. In our e ·i of exp rimen s in the d velo m nt f c s

eir cala ion t chniqu , we w · r not ware t th ti 1e of th va iou.s oth t• etudi it i f int r t \ha · at no tim h · v eri ne d any uch difficU;lty \vlth venous

r .:n the xec:ipi nt cr.· · r .... wide an f p r u ion ate involving ve~ 1 hundred th . 8 diffic tie in achi ving d . qu te v nous r tu--n

cribed bl. ome deta: by ·' dr · n nd thoil o v n us c nn tion (thr u h the f mor 6 1 Ve nt),

of a r tiv l y inei£ieient pump.

No auth r ha e r epor ed ppiication of pr viou ly •

c r o s circu ation technique in

.,·~bout Novemb r - December 1953 Doc to V· reo watched ever ·1 of th e r os ire tion op r;;1tio s invo ving ere ti n. ~ d cl ure £ interventric a r s pt de£ eta

a.nd he became an xtre ly ntbusia tic up orter of the m thod a you now. L ike .. wi · e, . b ut tb t time we invit .d th Pediatr ic· an , r . . ay .._ nd r~on, Dr . · au1 dam , · n Dr . Dw n, up to the · b to watch an 'nt _ v n r icu r p l def ct being p i ·din · do by thi me od. Theit· eaction w a nothing hort f l'na.zing . Thi

ccount for the fac th t w have met no i nc· wh tsoe er in o taining c l inical · tients. Fina!ly, I ahou!d ik o mention that octor Zi gler m y a r ah

o£ m ny in his f"e din hi 111etbod d know oft c:bnique ·for typin and c:ro matching blood. Thi act, which l d.id not ppreeiat until r cently, h been o£ h1 tim· ble value in in ur g afety forth donor&.

It i ik !y th t the d mon r· tion th pati nt with inte:rv ntric r a pt de­fect • -trioventricul ri communi , i o t d infun ib ar stenosis, and tetralo y of

c E

. • Owen H .

J.b :re

n enste n ... 7 ... ,.,ugu. t 6, 1954

Your ince e y,

i, • •

1.

z.

3. K

4.

S. n

6.

·nd sz.

iment 1 C cu r u g y. . r it. J. Sur ••

xc usion f th Do H t y 1bio i . J. t. Sin i o p. ,

t " ~.: · intena c o Circu tion eri-1· tion on th Open H a.r t. Th

ie c . c Circu tio for Intr c di c Sur y. . ch. ur • , . 3, . 195Z.

11: talC rdi- e Surg ry. ur ry. 3 : 9S-z 6, 19

Di cus ion of esu t 0 · r Obt ill d and port on nin Ponor Circ tion. it. J. u •• 1: 195- 6, 1953.