D.J. Blackmore and W.J. Elder- The artificial kidney and urea clearance
Transcript of D.J. Blackmore and W.J. Elder- The artificial kidney and urea clearance
8/3/2019 D.J. Blackmore and W.J. Elder- The artificial kidney and urea clearance
http://slidepdf.com/reader/full/dj-blackmore-and-wj-elder-the-artificial-kidney-and-urea-clearance 1/8
J . c l i n . P a t h . ( 1 9 6 1 ) , 1 4 , 4 5 5
T h e a r t i f i c i a l k i d n e y a n d urea c l e a r a n c e
D. J . BLACKMORE AND W. J . ELDER
From t h e R e s e a r c h D e p a r t m e n t , R . A . F . I n s t i t u t e o f P a t h o l o g y a n d T r o p i c a l M e d i c i n e a n d t h e R e n a l
U n i t , P r i n c e s s M a r y ' s R . A . F . H o s p i t a l , H a l t o n , A y l es b u r y , B u c k s .
SYNOPSIS A t h e o r e t i c a l e f f i c i e n c y h a s b e e n c a l c u l a t e d f r o m t h e known urea c l e a r a n c e o f t h ea r t i f i c i a l k i d n e y , t h e a s s u m e d t o t a l b o d y w a t e r o f t h e p a t i e n t , a n d t h e i n i t i a l p l a s m a u r e a .
T h e e f f i c i e n c y o f d i a l y s i s never s i g n i f i c a n t l y e x c e e d e d t h e c a l c u l a t e d f i g u r e . I n some p a t i e n t s w i t h
trauma o r g l o m e r u l o n e p h r i t i s t h e e f f i c i e n c y w as very po or w h e r e a s i n p a t i e n t s w i t h r e n a l f a i l u r ec o m p l i c a t i n g pregnancy t h e a c t u a l a n d c a l c u l a t e d e f f i c i e n c i e s w e r e very c l o s e .
T h e s e o b s e r v a t i o n s are d i s c u s s e d a n dp o s s i b l e
reasons
f o r t h e f a i l u r eo f d i a l y s i s t o b r i n g dow n
t h e p l a s m a urea t o t h e e x p e c t e d c o n c e n t r a t i o n are s u g g e s t e d .
W e h a v e b ee n s t r u c k b y t h e v a r i a b l e r e s u l t s o f
d i a l y s i s a s s e s s e d i n t e r m s o f p l a s m a u r e a f a l l a n d
c l i n i c a l r e s p o n s e w h i l e u s i n g a t w i n - c o i l a r t i f i c i a lk i d n e y d u r i n g t h e p a s t t h r e e y e a r s ( J a c k s o n , B u n k e r ,
E l d e r , a n d J o e k e s , 1 9 6 0 ) . I t h a s b e e n s u g g e s t e d t h a tt h e v a r i a b i l i t y o f d i a l y s i s i n v i v o m ay b e d u e t od i f f e r e n c e s i n b l o o d f l o w r a t e a n d c o i l e f f i c i e n c y( T r a v e n o l l e a f l e t p r o v i d e d w i t h e a c h d i s p o s a b l e c o i la n d E l l i o t t , H o r n , K e r r , a n d P e a r s o n , 1 9 6 1 ) . O u r
e x p e r i e n c e i n d i c a t e d t h a t t h e s e w e r e u n l i k e l y t o b e ac o m p l e t e e x p l a n a t i o n , e s p e c i a l l y a s p o s t - o b s t e t r i cp a t i e n t s c o n s i s t e n t l y r e s p o n d e d w e l l t o d i a l y s i s w i t h
h i g h p l a s m a u r e a c l e a r a n c e s w h e r e a s s o m e g l o m e r u -
l o n e p h r i t i c a n d p o s t - t r a u m a t i c p a t i e n t s h a d p o o r
c l e a r a n c e s a n d i m p r o v e m e n t i n t h e i r c l i n i c a l s t a t ew a s l e s s s a t i s f a c t o r y .
H a e m o d i a l y s i s h a s b e e n e x t e n s i v e l y i n v e s t i g a t e d i nv i t r o , a n d p a r a m e t e r s h a v e b e e n d e d u c e d w h i c h
a l l o w f o r m a t h e m a t i c a l a n a l y s i s o f a r t i f i c i a l k i d n e y
f u n c t i o n ( W o l f , R e m p , K i l e y , a n d C u r r i e , 1 9 5 1 ) . A ss u f f i c i e n t d a t a a r e a v a i l a b l e o n m o s t o f o u r d i a l y s e swe h a v e a c c o r d i n g l y a n a l y s e d t h e m w i t h r e s p e c t t ou r e a c l e a r a n c e .
MATERIAL AND METHODS
H a e m o d i a l y s e s w e r e p e r f o r m e d w i t h a K o l f f d i s p o s a b l e
t w i n - c o i l u n i t u s i n g a m o d i f i e d T r a v e n o l a r t i f i c i a l k i d n e y .T h e c o i l w a s s e a l e d i n t h e c a n w i t h s p o n g e r u b b e r a n d t h eb a t h f l u i d c i r c u l a t i n g pump a l t e r e d t o g i v e a c o n s t a n t
f l o w o f 3 4 l i t r e s p e r m i n u t e u n d e r v a r i a b l e l o a d . T h eb l o o d f l o w r a t e w a s m e a s u r e d b y e l e c t r o m a g n e t i ci n d u c t i o n ( B r e n n a n d a n d B u n k e r , 1 9 6 0 ) . S o d i u m a n dp o t a s s i u m c o n c e n t r a t i o n s i n t h e d i a l y s i n g f l u i d v a r i e d
R e c e i v e d f o r p u b l i c a t i o n 1 2 J u l y 1 9 6 1 .
f r o m p a t i e n t t o p a t i e n t b u t n o u r e a w a s a d d ed . U r e a w a s
e s t i m a t e d o n h e p a r i n i z e d p l a s m a b y a u r e a s e - n e s s l e r i z a -t i o n t e c h n i q u e ( K i n g a n d W o o t t o n , 1 9 5 6 ) . H i g h p l a s m au r e a s ( > 1 0 0 m g . / 1 0 0 m l . ) w e r e d i l u t e d b e f o r e e s t i m a t i o n .A l l t e s t s w e r e p e r fo r m e d i n d u p l i c a t e w i t h a d e q u a t e c o n -
t r o l o f r e c o v e r y a n d s t a n d a r d s o l u t i o n s .D i a l y s e s w h i c h f u l f i l l e d t h e f o l l o w i n g c r i t e r i a w e r e
s e l e c t e d f o r i n c l u s i o n i n t h i s i n v e s t i g a t i o n : -I , C l i n i c a l l y u n e v e n t f u l , u n i n t e r r u p t e d s i x - h o u r d i a l y s e s ;
2 , d i a l y s i n g f l u i d c h a n g e d a t t w o - h o u r i n t e r v a l s ; 3 , b l o o d
f l o w r a t e c o n s t a n t ( ± 2 0 m l . / m i n . ) w i t h i n t h e r a n g e 2 5 0 t o4 0 0 m l . / m i n . ; 4 , c i r c u i t o u t f l o w p r e s s u r e l e s s t h a n 8 0 m m .H g ; 5 , p a t i e n t ' s w e i g h t b e t w e e n 5 0 a n d 8 0 k g . ; a n d 6 , c o n -
s i s t e n t b i o c h e m i c a l d a t a w e r e a v a i l a b l e . S i x t y o u t o f 2 2 2
d i a l y s e s f u l f i l l e d t h e s e r e q u i r e m e n t s .I f u r e a i s e v e n l y d i s t r i b u t e d a n d f r e e l y d i f f u s i b l e
t h r o u g h o u t t h e t o t a l b o d y w a t e r i t s h o u l d b e p o s s i b l e t o
c a l c u l a t e t h e e x p e c t e d p l a s m a u r e a a t t h e e n d o f d i a l y s i sf r o m t h e i n t i t i a l p l a s m a u r e a a n d t h e u r e a c l e a r a n c e o f
t h e a r t i f i c i a l k i d n e y . I t w o u l d a l s o b e r e a s o n a b l e t o a s s u m e
t h a t d e l a y i n i n t r a c e l l u l a r f l u i d - e x t r a c e l l u l a r f l u i de q u i l i b r a t i o n a n d t h e r a t e o f u r e a p r o d u c t i o n d u r i n g
d i a l y s i s w o u l d h a v e l i t t l e e f f e c t .A nomogram ( F i g . 1 ) w a s c o n s t r u c t e d t o g i v e t h e
e x p e c t e d p l a s m a u r e a a t t h e e n d o f d i a l y s i s a s s u m i n g t h a tt h e t o t a l b o d y w a t e r w a s 57% o f t h e b o d y w e i g h t . T h e
nomogram w a s b a s e d o n t h e e q u a t i o n d e r i v e d b y W o l fe t a l . ( 1 9 5 1 ) u s i n g s t a n d a r d n o m o g r a p h i c t e c h n i q u e . T h e
f o l l o w i n g i s a n e x a m p l e o f i t s u s e :L e t p a t i e n t ' s p r e - d i a l y s i s p l a s m a u r e a - 4 0 0 m g . %L e t p a t i e n t ' s b o d y w e i g h t 7 0 k g .L e t b l o o d f l o w r a t e d u r i n g d i a l y s i s - 3 0 0 m l . / m i n .
t h e n f r o m nomogram1 S e t t i n g 4 0 0 ( i n i t i a l u r e a A o ) o n s c a l e A a n d 7 0 k g .
( b o d y w e i g h t ) o n s c a l e D t h e e x p e c t e d p l a s m a u r e a a t2 h o u r s i s o b t a i n e d a t s c a l e F a g a i n s t t h e 7 0 k g . l i n e ( 2 4 0 ) .
2 R e p e a t w i t h Ao a t 2 4 0 , t h e n a t 4 h o u r s e x p e c t e d
p l a s m a u r e a i s 1 4 5 .
4 5 5
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D . J . B l a c k m o r e a n d W . J . E l d e r
F LOWRATEM I J o I s .
400
300
200-
100
0 -
C
F I G . 1 .
[Bt V Ct]
B V F
D EF
N o m o g r a m f o r d e t e r m i n i n g e x p e c t e d p l a s m a u r e a .|= 2 h o u r s ( 1 2 0 m i n . )C = c l e a r a n c e ( a s f o u n d b y E l l i o t t e t a l . , 1 9 6 1 )
V Ao = i n i t i a l p l a s m a u r e a ( m g . / 1 0 0 m l . )+ A o B + V A t = e x p e c t e d p l a s m a u r e a ( m g . / 1 0 0 n i l . )
e = 2 - 7 2
3 R e p e a t s e t t i n g Ao a t 1 4 5 , t h e n a t 6 h o u r s e x p e c t e d
p l a s m a urea i s 9 0 .
S h o u l d t h e b l o o d f l o w r a t e n o t b e 3 0 0 m I . / m i n . , i t i s
c o r r e c t e d a t e a c h s t a g e u t i l i z i n g s c a l e s B , C , an d E i n a
s i m i l a r m a n n e r .
S o t h a t c o m p a r i s o n b e t w e e n d i a l y s e s would b e p o s s i b l ea r e l a t i o n s h i p b e t w e e n t h e c a l c u l a t e d a n d o b s e r v e d p o s t -
d i a l y s i s p l a s m a urea was d e r i v e d as f o l l o w s :
1 [ U cUc o e f f i c i e n c y i n d e x
Uc c a l c u l a t e d i m m e d i a t e p o s t - d i a l y s i s p l a s m a urea
Uo o b s e r v e d i m m e d i a t e p o s t - d i a l y s i s p l a s m a urea
EXAMPLE L e t t h e c a l c u l a t e d i m m e d i a t e p o s t - d i a l y s i sp l a s m a urea ( U c ) = 9 0 m g . % .
L e t t h e o b s e r v e d i m m e d i a t e p o s t - d i a l y s i s p l a s m a urea
( U o ) = 1 5 0 m g. % , t h e n
e f f i c i e n c y i n d e x =100 [ 9 0 9 0 1 5 0 1 - 6 6
RESULTS
When t h e r e s u l t s o f t h e 6 0 d i a l y s e s w e r e a s s e s s e d i n
t h i s way i t was e v i d e n t t h a t t h e r e was some r e l a t i o n -
4 5 6
A t E R.300
t SOO
_400
- 3 0 0
-200
-100
-0
AO
dl̂ ^1 . V J 0
90 0
S QO
700
60 0
500
400-
30 0
200 -
1 0 0 -
0-
A
A t
BV
I
B
B + v 0
d i a l y s i n g f l u i d v o l u m e ( m l . )= t o t a l b o d y w a t e r 4 / 7 k g . ( m l . )
1 1
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T h e a r t i f i c i a l k i d n e y a n d urea c l e a r a n c e 4 5 7
TABLE I
RELATION BETWEEN CLINICAL CONDMON, EFFICIENCY INDEX, AND RATES PLASMA UREA R I S E
S e x A g e N o . o f Day o f P r e - E f f i c i e n c y R a t e o f R a t e o f R a t i o o f
D i a l y s i s O l i g u r i a d i a l y s i s I n d e x P r e - P o s t - P o s t -
P l a s m a d i a l y s i s d i a l y s i s t o P r e -
U r e a P l a s m a P l a s m a d i a l y s i s( m g .°) U r e a U r e a R a t e s o f
R i s e ' R i s e ' R i s e
T r a u m a t i c
G . H . H . M u l t i p l e i n j u r i e s
R . L . A o r t i c v a l v o t o m y
C . T . H . P r o s t a t e c t o m y
B . J . M u l t i p l e i n j u r i e s
J . W . K . M u l t i p l e i n j u r i e s
A . V . R e s e c t i o n o f c a r c i n o m a c o l o n
R . V . M u l t i p l e i n j u r i e s
H . S . M u l t i p l e i n j u r i e sD . S . F u s i o n c e r v i c a l s p i n e
A . D . F a c i a l i n j u r i e sG . H . A p p e n d i c e c t o m y
H . C . H . P a r t i a l g a s t r e c t o m y
C . H . S . P a r t i c a l g a s t r e c t o m y
G l o m e r u l o n e p h r i t i cR . S . C h r o n i cP . L . S u b a c u t e
L . W . C . C h r o n i cJ . C . M . C h r o n i c
G.A.W. S u b a c u t e
J . L . A c u t e
R . N . C h r o n i cD.A.M. S u b a c u t eA . P . S u b a c u t e
C . T . C h r o n i cO b s t e t r i cR . T . A c c i d e n t a l h a e m o r r h a g e 3 6 / 5 2
I . J . A b o r t i o n 2 6 /5 2
M.H. S e p t i c a b o r t i o n 1 2 / 5 2
S . S . A c c i d e n t a l h a e m o r r h a g e 3 6 / 5 2
J . V . E c l a m p s i a - s t i l l b i r t h 2 8 / 5 2
M i s c e l l a n e o u sW . H . S . M a l i g n a n t h y p e r t e n s i o n
J . G . M y o c a r d i a l i n f a r c t i o nL . S . N a C 1 0 3 p o i s o n i n g
H . D . B a c i l l a r y d y s e n t e r y
B . M . M . T . m a l a r i a
J . P . C C l 4 p o i s o n i n g
B . R . . D i s s e c t i n g a n e u r y s m
M 5 4 2
34
M 5 8 1M 6 1 1
M 2 1 12
M 2 1 12
M 7 6 1
M 3 6 134
F 1 6 1F 4 3 1
2M 1 9 1
M 6 4 1
2
3M 6 3 1
2
34
M 4 4 1
M 2 2 1
M 5 2 1
M 4 2 1M 3 6 2
34
M 4 3 12
3M 3 9 1M 6 2 2
M 2 0 1M 3 3 1
M 4 4 1
F 4 1 1
F 3 5 1
2
F 2 6 1
F 2 3 13
F 2 2 3
M 3 6 1F 6 5 1
M 4 8 12
34
M 5 1 12
M 3 6 2
34
M 5 6 12
M 7 3 1
1 2
1 82 697
7
1 469
1 36
1 4
1 89
1 31 6S
61 0
1 5
6
1 2
2 03 6
6
1 4 31 1
1 11 6
2 32 22 83 3
2 91 2
1 0
1 21 1
1 2
1 32 5
1 31 12 4
2 6
1 0
7
61 11 8
2 49
1 4
91 2
1 69
1 6
7
6 0 0 -5 5 0 - 8 55 0 0 -5 5 0 - 3 1
5 2 0 -1 6 033
3 5 0 -7 7 01 9 080
3 8 0 -52 0 - 2 6 0 - 4 3
3 5 0 -46 0 3 7 0 - 4 8
3 9 0 -1 5 0 - 4 14 9 0 -60 0 - 4 8
5 5 0 -34 0 - 8 0
2 5 0 -1 4 0 - 2 13 6 5 -7 2 0 - 3 4 0 4 1
5 6 0 -47 0 5 1 047
5 0 0 -43 0 2 7 0 5 63 7 0 -5 6 0 1 5 0 - 2 7
3 7 0 -52 0 4 7
3 8 0 -69 0 - 2 9 0 4 44 0 0 -108 0 - 4 6 0 - 9 33 9 0 -7 6 0 5 84 0 0 -36 0 5 55 4 0 -2 0 - 5 1 0 - 2 13 3 5 -5 6 0 3 3
3 2 0 -62 01 6 0443 1 5 -2 2 0 - 1 4
4 2 0 -7 5 0 3 4
4 1 0 -93 0 8 1
4 4 0 -61 0 - 2 5 0 2 9
4 3 0 -115 0 4 7 0 5 1
4 9 0 -42 0 - 4 9
4 6 0 -140 0 - 5 5
4 7 0 -8 8 049
5 9 0 -92 0 - 2 16 2 0 -69 082 0384 9 0 -63 0 - 3 7 6 0 - 4 14 1 0 -133 01 5 0 - 5 7
4 9 0 -40 0 3 1 0 - 2 85 0 0 -140 0 6 1 0 - 6 8
3 0 0 -94 0 - 3 25 0 0 -40 0 - 1 4
5 3 5 -110 0 - 8 3 0 - 5 9
3 4 0 -1 4 02 06 7 0 - 8 0 0 53 0 0 + 3 01 54 1 5 + 3 0 3 9 0 - 2 7
3 5 5 - 6 0 - 2 4 02 5
3 2 0 +1 5 021 0344 1 0 - 7 031 02 6
4 9 0 - 8 0 3 3 0 4 3
4 4 0 - 5 6 0 - 1 7 7 0 - 3 9
4 3 0 - 5 0 0 - 3 3 8 0 - 5 5
4 9 0 -164 0 - 4 1 0 6 5
5 4 0 - 3 1 0 - 2 4 2 0 - 2 95 0 0 - 6 2 0 4 7 0 - 3 5
5 6 0 -118 0 - 3 3 0355 2 0 - 2 7 0304 6 0 - 2 2 0 - 4 2 0 - 6 1
3 7 0 - 5 0 0 - 4 0 0 - 6 3
5 0 0 -100 0 5 9 0 - 4 6 54 5 0 -200 0 - 4 2 0 54 6 5 -100 0 - 3 6 0 - 3 9
4 0 0 - 1 2 0 - 2 6 0 - 7 1
' R a t e o f p l a s m a urea r i s e c a l c u l a t e d f o r 48 hours p r e - d i a l y s i s expressed i n mg./kg. body weight/hour.
2 R a t e o f p o s t - d i a l y s i s p l a s m a urea r i s e c a l c u l a t e d f o r 40 hours p o s t - d i a l y s i s , expressed in mgm/kg. body weight/hour.
3 T h e onset o f o l i g u r i a i n t h e g l o m e r u l o n e p h r i t i c group was o f t e n i n s i d i o u s or not accurately known, thus t he figures given are approximate.
4 . 31 - 6 51 - 3
1 - 20942 11 8
1 . 5205
04
27
1 - 1 51 - 0 9
0451 * 13 - 7 6091 - 1 5
0 - 7 1
0 - 6 9
1 - 0 51 - 60 - 8 4
1 3 02 - 2 6
1 - 6 61 - 61 - 20751 - 0 6
1 - 4 51 60791 - 20 - 9 12 - 7
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D . J . B l a c k m o r e a n d W . J . E l d e r
o GLOMERULONEPHRITIC
9 l TRAUMATIC-160
0
-120-
z
Uzw - 8 0 .
U.
I F40
E :0
9 10 1 - 0 . 2 0 : 3 04
R20-dUREARISE in m g . I / Kg . body w t . I / hour
3 OBSTETRIC
, & MISCELLANEOUS
0
0.REA-ISE n064.OdyO0m7I0t9-8
UREA R I S E i n m g . / K g . b o d y w t . / h o u r p
F I G . 2 . E f f i c i e n c y i n d e x r e l a t e d t o p r e - d i a l y s i s r a t e o f
p l a s m a urea r i s e f o r g l o m e r u l o n e p h r i t i c a n d t r a u m a t i c
groups.
s h i p b e t w e e n t h e a e t i o l o g y o f t h e p r i m a r y c o n d i t i o n
a s s o c i a t e d w i t h t he r en a l f a i l u r e an d t h e e f f i c i e n c yi n d e x o f d i a l y s i s ( T a b l e I ) . The 2 5 d i a l y s e s on 1 3
p a t i e n t s w i t h trauma had a n e f f i c i e n c y i n d e x b e t w e e n
-2 a n d - 1 0 8 , a n d , o f t h e s e , 2 3 d i a l y s e s had an
e f f i c i e n c y i n d e x b e t w e e n -2 and -80. The 1 4
d i a l y s e s o n 1 0 p a t i e n t s w i t h g l o m e r u l o n e p h r i t i s had
a n e f f i c i e n c y i n d e x b e t w e e n -40 an d -140 a n d , o f
t h e s e , e i g h t d i a l y s e s had a n e f f i c i e n c y i n d e x b e t w e e n
-80 a n d - 1 4 0 . The seven d i a l y s e s on f i v e p o s t -
o b s t e t r i c p a t i e n t s had a n e f f i c i e n c y i n d e x b e t w e e n
-14 a n d + 1 5 . The r e m a i n i n g 1 4 d i a l y s e s on seven
p a t i e n t s w i t h o t h e r c o n d i t i o n s had a w i d e s c a t t e r o f
e f f i c i e n c y i n d i c e s from -200 t o -8 .
EFFICIENCY INDEX RELATED TO PRE-DIALYSIS RATE OF
PLASMA UREA R I S E The e f f i c i e n c y i n d e x i n t h e f o u r
groups w as p l o t t e d a g a i n s t t h e p r e - d i a l y s i s r a t e o f
p l a s m a urea r i s e f o r t h e 4 8 h o u r s b e f o r e d i a l y s i s( F i g s . 2 an d 3 ) .N o c o r r e l a t i o n was f o u n d an d no s i g n i f i c a n t d i f -
f e r e n c e was a p p a r e n t b e t w e e n t h e g r o u p s .
EFFICIENCY I N D E X RELATED TO POST-DIAL YSIS RATE OF
PLASMA UREA R I S E The e f f i c i e n c y i n d e x was a l s o
p l o t t e d a g a i n s t t h e p o s t - d i a l y s i s r a t e o f p l a s m a urea
r i s e f o r t h e 4 0 h o u r s a f t e r d i a l y s i s ( F i g s . 4 an d 5 ) .A s i g n i f i c a n t c o r r e l a t i o n e x i s t e d b e t w e e n t h e d i a l y s i se f f i c i e n c y i n d e x an d t h e p o s t - d i a l y s i s r a t e of r i s e of
urea i n t h e t r a u m a t i c an d g l o m e r u l o n e p h r i t i c g r o u p s .
There w as a l s o a s t a t i s t i c a l l y s i g n i f i c a n t d i f f e r e n c e
F I G . 3 . E f f i c i e n c y i n d e x r e l a t e d t o p r e - d i a l y s i s rate o f
p l a s m a u i r e a r i s e f o r o b s t e t r i c a n d m i s c e l l a n e o u s groups.
b e t w e e n t h e s e two groups ( t =4 - 0 8 a n d p < 0 - 0 0 1 ) .
The d i f f e r e n c e b e t w e e n t h e o b s t e t r i c p a t i e n t s and t h e
o t h e r two groups w as o b v i o u s .
EFFICIENCY I N D E X RELATED TO RATIO POST-DIALYSIS:
PRE-DIALYSIS RATES O F P LA S MA UREA RISE The r a t i o
o f t h e p o s t - d i a l y s i s t o t h e p r e - d i a l y s i s r a t e o f p l a s m a
urea r i s e was p l o t t e d a g a i n s t t h e e f f i c i e n c y i n d e x i nt h e f o u r groups ( F i g s . 6 a n d 7 ) . A g a i n t h e r e was no
c o r r e l a t i o n i n a n y group b e t w e e n t h e r a t i o a n d
e f f i c i e n c y i n d e x .
F i g u r e 6 s h o w s t h a t , i g n o r i n g t h e e f f i c i e n c y i n d e x ,t h e r e w as a d i f f e r e n c e b e t w e e n t h e t r a u m a t i c a n d
g l o m e r u l o n e p h r i t i c groups i n r e s p e c t o f t h e p o s t -
d i a l y s i s t o p r e - d i a l y s i s r a t e o f r i s e . I t appears t h a tt r a u m a t i c p a t i e n t s h a d a s i g n i f i c a n t i n c r e a s e i n t h e
r a t e o f p l a s m a urea r i s e a f t e r d i a l y s i s .
EFFICIENCY I N D E X RELATED TO DAYS O F OLI GURIA Int h e t r a u m a t i c a n d g l o m e r u l o n e p h r i t i c groups t h e
d i a l y s i s e f f i c i e n c y i n d e x was p l o t t e d a g a i n s t t h e t i m e
i n d a y s a f t e r t h e o n s e t o f o l i g u r i a ( F i g s . 8 a n d 9 ) .N o o b v i o u s c o r r e l a t i o n a p p e a r e d t o e x i s t b e t w e e n
t h e e f f i c i e n c y i n d e x a n d d a y s o f o l i g u r i a i n t h e
g l o m e r u l o n e p h r i t i c o r o b s t e t r i c groups. I n t h e
trauma group t h e d i a l y s e s t e n d e d t o b e c o m e more
e f f i c i e n t w i t h i n c r e a s i n g l e n g t h o f o l i g u r i a , w i t h t h e
e x c e p t i o n o f one p a t i e n t ( H . C . H . , T a b l e I ) d i a l y s e don t h e t h i r t y - s i x t h d a y f r o m o n s e t o f r e n a l f a i l u r e ,w ho h a d b e g u n a d i u r e s i s (>1 1 . u r i n e v o l u m e / 2 4
h o u r s ) f o u r d a y s b e f o r e . I t i s d i f f i c u l t t o d e c i d e
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F I G . 4 . E f f i c i e n c y i n d e x r e l a t e d t o p o s t - d i a l y s i s r a t e o f p l a s m a u r e a r i s e f o r g l o m e r u l o n e p h r i t i c a n d t r a u m a t i c
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p r e - d i a l y s i s r a t e o f p l a s m a urea r i s e f o r g l o m e r u l o n e p h r i t i ca n d t r a u m a t i c groups.
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T h e a r t i f i c i a l k i d n e y a n d u r e a c l e a r a n c e
TABLE I I
PREDICTED AND OBSERVED UREA REMOVED AT D I A L Y S I S
N o . o fD i a l y s i s
T h e o r e t i c a l A c t u a l A c t u a l : T h e o r e t i c a lU r e a U r e a U r e aRemoved ( g . ) Removed ( g . ) Removed ( g . )
M u l t i p l e i n j u r i e s
C . T . H . ' P r o s t a t e c t o m yJ . N . M u l t i p l e i n j u r i e s
B . J . l M u l t i p l e i n j u r i e s
J . W . K . ' M u l t i p l e i n j u r i e s
G l o m e r u l o n e p h r i t i cJ . E . H . A c u t eW . B . C h r o n i c
A b o r t i o n 2 6 / 5 2P o s t - p a r t u m h a e m o r r h a g e
23
2
2
2
2
1 1 01 1 98 76 0 - 5
7056 8 - 5
1 0 4
1 1 4
8 7
1 4 0
8 6 - 2
9 2
9 6 - 6904
1 1 0
2 3 33 9 - 2
7 69 3 - 2
1 0 16 9
1 0 9
8 8 - 6
1 0 1 16 5 - 1
1 1 2 - 2
7 3 . 31 3 0
1 3 5 - 7
4 68 0
8 21 2 0
1 3 5 - 6
1 7 9 - 4
4 3 . 7 5
8 4 - 6
8 1
0 - 9 20 5 81 - 2 51 - 4 61 - 4 30951 - 0 80 - 6 4
1 - 4 9097
0530 - 8 7
0851 - 3 31 - 2 30771 - 1 5
1 * 10 - 8 6
The t h e o r e t i c a l u r e a r e m o v a l was c a l c u l a t e d f r o m t h e p l a s m a urea f a l l o b s e r v e d across d i a l y s i s a s s u m i n g t h a t t h e t o t a l b o d y water was 5 7 % o ft h e b o d y w e i g h t .
' T h e d i a l y s e s o f t h e s e p a t i e n t s ar e a l s o i n c l u d e d i n T a b l e I .
w h e t h e r t h e i m p r o v i n g p l a s m a urea c l e a r a n c e w as a
f u n c t i o n o f t i m e o r w h e t h e r i t w as r e l a t e d t o p r e v i o u s
d i a l y s e s .
PREDI CTED AND OBSERVED UREA REMOVED BY
DIALYSIS U n f o r t u n a t e l y an a c c u r a t e e s t i m a t e o f t h e
t o t a l amount o f urea r e m o v e d b y d i a l y s i s i s o n l y
a v a i l a b l e i n 1 9 d i a l y s e s ( T a b l e I I ) , a n d o n l y f i v e o f
t h e s e p a t i e n t s c o u l d b e i n c l u d e d i n t h e p r e s e n t paper.
I n g e n e r a l t h e r e s u l t s are e q u i v o c a l , b u t i n t h e
t r a u m a t i c group t h e urea r e m o v e d d u r i n g t h e
s e c o n d d i a l y s i s was l e s s t h a n t h a t r e m o v e d b yt h e f i r s t d i a l y s i s .
DISCUSSION
I t i s o f i n t e r e s t t h a t o n l y t h o s e p a t i e n t s w i t h a c u t er e n a l f a i l u r e c o m p l i c a t i n g pregn a n cy b e h a v e i n t h e
p r e d i c t e d manner w i t h r e s p e c t t o urea c l e a r a n c e .A l s o i t appears f r o m o n l y two e s t i m a t i o n s o f urea
r e m o v a l b y d i a l y s i s ( T a b l e L I ) t h a t t h e y l o s e t h e i rurea t o t h e d i a l y s i n g f l u i d i n a s i m i l a r l y p r e d i c t a b l ew a y .
We h a v e f o u n d t h a t p a t i e n t s w i t h a c u t e r e n a lf a i l u r e c o m p l i c a t i n g trauma h a v e a poor p l a s m aurea c l e a r a n c e on t h e i r f i r s t d i a l y s i s w i t h t h e pre-
d i c t e d o r more t h a n t h e p r e d i c t e d amount o f urea
r e m o v e d a n d a n i m p r o v e d c l e a r a n c e w i t h a l o w e r
urea r e m o v a l i n s u b s e q u e n t d i a l y s e s . T h e y a l s os h o w e d a s i g n i f i c a n t l y g r e a t e r p o s t - d i a l y s i s r a t e o fp l a s m a urea r i s e t h a n t h e p r e - d i a l y s i s r i s e an d t h e
l e s s e f f i c i e n t t h e i r d i a l y s e s t h e g r e a t e r w as t h e p o s t -
d i a l y s i s r a t e o f p l a s m a urea r i s e .The l e a s t e f f i c i e n t p l a s m a urea c l e a r a n c e i n t h i s
s e r i e s w as f o u n d i n p a t i e n t s w i t h g l o m e r u l o n e p h r i t i s .
T h o s e p a t i e n t s w i t h r e n a l f a i l u r e o f a e t i o l o g y o t h e r
t h a n t h e t h r e e groups m e n t i o n e d p r e s e n t e d a w i d e
range o f r e s u l t s , t h e m a j o r i t y o f w h i c h d e v i a t e d f r o m
t h e p r e d i c t e d f i g u r e s .I n t r y i n g t o i n t e r p r e t t h e s e a n o m a l o u s f i n d i n g s t h e
p o s t u l a t e made b y M e r r i l l ( M e r r i l l q u o t e d b y M a t h e r ,1 9 6 0 ) t h a t , i n some p a t i e n t s , d i a l y s i s r e l e a s e s a
m e t a b ol i c b l o c k t o t h e p r o d u c t i o n o f urea s h o u l d b ec o n s i d e r e d . I f t h i s i s t o a c c o u n t f o r t h e v a r i a t i o n i n
p l a s m a urea c l e a r a n c e enormous q u a n t i t i e s o f ureaw o u l d h a v e t o b e p r o d u c e d d u r i n g d i a l y s i s t o a f f e c tm a t e r i a l l y t h e c a l c u l a t e d r e s u l t . The r a t e o f urea pro-
d u c t i o n i n t h e b o d y o f a n o r m a l man w e i g h i n g 7 0 k g .i s o f t h e o r d e r o f 1 g . pe r h o u r ; t h e p r o d u c t i o n o f6 g . o f urea i n as many h o u r s w o u l d o n l y i n c r e a s et h e b l o o d urea b y 1 5 m g . / 1 0 0 m l . A urea p r o d u c t i o nas h i g h as t h r e e t i m e s n o r m a l c o u l d n o t s i g n i f i c a n t l ya f f e c t t h e e f f i c i e n c y i n d e x . A l s o , i t m i g h t b e e x p e c t e dt h a t t h e p o s t - d i a l y s i s r a t e o f p l a s m a urea r i s e w o u l db e much g r e a t e r t h a n t h e p r e - d i a l y s i s r a t e . A l t h o u g ht h i s was seen i n t h e t r a u m a t i c g r o up ( s e e F i g . 6 ) i t was
T r a u m a t i c
S . H .
C h r o n i cC h r o n i cA c u t e
C h r o n i c
V . C .R . N . 1
W . W .
CC.
O b s t e t r i cI J . sJ . S .
4 6 1
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D . J . B l a c k m o r e a n d W . J . E l d e r
n o t f o u n d i n m o s t o f t h e g l o m e r u l o n e p h r i t i c g r o u p
w h e r e a n e f f i c i e n c y i n d e x o f b e t w e e n -80 a n d -140w a s c o m m o n . I n t h e l a t t e r g r o u p i t w a s a l s o o b s e r v e d ,w i t h o n l y o n e e x c e p t i o n , t h a t t h e c a l c u l a t e d u r e a
r e m o v a l b y d i a l y s i s a p p r o x i m a t e d t h e a c t u a lr e m o v a l .
A n o t h e r p o s s i b l e e x p l a n a t i o n i s t h a t u r e a e x i s t sb o t h i n c e l l a n d p l a s m a i n d i f f u s i b l e a n d n o n -
d i f f u s i b l e f o r m s a n d t h a t t h e r e i s a g r e a t e r r a t i o o f
n o n - d i f f u s i b l e t o d i f f u s i b l e u r e a i n t h e c e l l t h a n i n t h ep l a s m a , t h e s e l e v e l s b e i n g m a i n t a i n e d i n e q u i l i b r i u m .T h e r a t i o m i g h t b e d e t e r m i n e d b y t h e a e t i o l o g y o f
t h e p r i m a r y c o n d i t i o n .T h e r e f o r e o n d i a l y s i s t h e f o l l o w i n g o b s e r v a t i o n s
w o u l d b e m a d e : 1 An i n c r e a s e d r a t i o o f n o n -
d i f f u s i b l e t o d i f f u s i b l e p l a s m a o r c e l l u r e a w o u l d
l o w e r t h e e f f i c i e n c y i n d e x . 2 I n t h e t r a u m a t i c g r o u p
a n i n c r e a s e d r a t i o o f n o n - d i f f u s i b l e t o d i f f u s i b l e c e l lu r e a b e f o r e d i a l y s i s m i g h t r e s u l t i n a h i g h e r c e l l
t h a n p l a s m a t o t a l u r e a c o n c e n t r a t i o n . I f t h i s i s s ot h e t o t a l b o d y u r e a c o n c e n t r a t i o n w o u l d b e h i g h e rt h a n t h a t c a l c u l a t e d f r o m t h e p l a s m a u r e a l e v e l .T h e r e f o r e m o r e u r e a c o u l d p a s s i n t o t h e d i a l y s i n gf l u i d t h a n p r e d i c t e d f r o m t h e p l a s m a u r e a d r o p . T h u s
i t i s n o t n e c e s s a r y t o p o s t u l a t e t h e r e l e a s e o f a
m e t a b o l i c b l o c k t o t h e p r o d u c t i o n o f u r e a t o a c c o u n t
f o r t h e e x c e s s u r e a i n t h e b a t h . D u r i n g d i a l y s i s t h ee q u i l i b r i u m w o u l d b e d i s t u r b e d a n d a s u b s e q u e n t
d i a l y s i s f o l l o w i n g r e - e s t a b l i s h m e n t o f a n e q u i l i b r i u ma t a l o w er n o n - d i f f u s i b l e l e v e l w o u l d r e s u l t i n a b e t t e re f f i c i e n c y i n d e x w i t h a l o w e r r e c o v e r y o f u r e a f r o m
t h e b a t h t h a n w a s f o u n d f o r m e r l y . 3 I n t h e g l o m e r u -l o n e p h r i t i c g r o u p a g r e a t e r r a t i o o f n o n - d i f f u s i b l et o d i f f u s i b l e p l a s m a u r e a b u t a l o w e r r a t i o o f n o n -
d i f f u s i b l e t o d i f f u s i b l e c e l l u r e a t h a n i n t h e t r a u m a t i c
g r o u p m i g h t r e s u l t i n a l o w e r e f f i c i e n c y i n d e x , w i t h a n
a p p r o x i m a t e t h e o r e t i c a l u r e a r e c o v e r y f r o m t h e b a t h
a n d a l o w e r p o s t - d i a l y s i s r i s e i n p l a s m a u r e a .
C O N C LU S I O N
W e c o n c l u d e f r o m o u r r e s u l t s t h a t i t i s d i f f i c u l t t o
a c c e p t u r e a a s a f r e e l y d i f f u s i b l e , r a p i d l y e q u i l i b r a t i n gs u b s t a n c e i n a l l p a t i e n t s . O n l y i n t h e o b s t e t r i c g r o u p
d o e s t h i s a s s u m p t i o n a p p e a r t o a l l o w a c c u r a t e p r e -d i c t i o n o f d i a l y s i s r e s u l t s .
T h e r e s u l t s f r o m o u r o t h e r g r o u p s s u g g e s t t h a t i ns o m e c i r c u m s t a n c e s t h i s i s n o t w h o l l y t r u e a n d t h a tu r e a m i g h t e x i s t i n b o t h d i f f u s i b l e a n d n o n - d i f f u s i b l e
f o r m s . W e a l r e a d y h a v e s o m e e x p e r i m e n t a l e v i d e n c e
s u p p o r t i n g t h i s t h e s i s b u t s o f a r t o o f e w c a s e s t oj u s t i f y a n y f i r m c o n c l u s i o n b u t w e h o p e t h a t p u b l i -c a t i o n a t t h i s s t a g e m i g h t i n t e r e s t o t h e r u n i t s w o r k i n g
i n t h i s f i e l d .F o l l o w i n g t h e p r e p a r a t i o n o f t h i s p a p e r f o r
p u b l i c a t i o n M u r d a u g h a n d D o y l e ( 1 9 6 1 ) h a v e r e -p o r t e d t h e b i n d i n g o f u r e a b y h a e m o g l o b i n a n d
a l b u m i n . T h e y a l s o s h o w e d t h a t t h e q u a n t i t y o f u r e a
b o u n d w a s r e l a t e d t o t h e u r e a c o n c e n t r a t i o n , i n d i -c a t i n g t h a t t h e u r e a - b i n d i n g r a t i o s o f h a e m o g l o b i na n d a l b u m i n w i l l n o t b e c o m e s a t u r a t e d i n t h e r a n g e
1 0 t o 4 0 0 m g . u r e a / 1 0 0 m l . T h e s e a u t h o r s a l s o r e p o r tt h a t o t h e r s h a v e s u g g e s t e d t h a t p r o t e i n w i l l b i n d u r e a .R a l l s ( 1 9 4 3 ) s h o w e d t h a t u r e a w a s n o t e q u a l l y d i s -t r i b u t e d b e t w e e n r e d c e l l w a t e r a n d p l a s m a w a t e r
a n d f o u n d a n a v e r a g e d i s t r i b u t i o n o f 1 - 1 4 : 1 - 0 0 .P a s y n s k i i a n d C h e r n y a k ( 1 9 5 0 ) r e p o r t e d t h a t t h ea d s o r p t i o n o f u r e a o n a l b u m i n a n d g l o b u l i n w a s
n o t r e l a t e d t o t h e i r r e s p e c t i v e w a t e r c o n t e n t a n ds u g g e s t e d t h a t o n a m o l a r b a s i s o n e u r e a u n i t w i l lb i n d w i t h t w o a m i n o - a c i d r e s i d u e s .W e f e e l t h e r e f o r e t h a t i t i s p o s s i b l e t h a t p r o t e i n
b i n d i n g o f u r e a c o u l d b e a n e x p l a n a t i o n o f i t s a p -
p a r e n t n o n - d i f f u s i b i l i t y . I t i s a l s o p o s s i b l e t h a t a
f a c t o r c o n t r o l l i n g t h e d e g r e e o f b i n d i n g may v a r y
w i t h t h e a e t i o l o g y o f t h e p r i m a r y c o n d i t i o n p r e c e d i n g
r e n a l f a i l u r e .
We w i s h t o t h a n k t h e D i r e c t o r G e n e r a l o f M e d i c a l
S e r v i c e s o f t h e R o y a l A i r F o r c e f o r p e r m i s s i o n t o p u b l i s h ,A i r C o m m o d o r e s W. P . Stamm a n d R . C . J a c k s o n f o rt h e i r e n c o u r a g e m e n t , D r . A . M. J o e k e s f o r h i s a d v i c e ,a n d D r . C . H . B o w d e n f o r h i s a s s i s t a n c e i n t h e i n t e r -p r e t a t i o n o f t h e f i n d i n g s .
REFERENCES
B r e n n a n d , R . , a n d B u n k e r , N . V . ( 1 9 6 0 ) . L a n c e t , 1 , 5 7 8 .E l l i o t t , W . , H o r n , D . B . , K e r r , D . N . S . , a n d P e a r s o n , D . T . ( 1 9 6 1 ) .
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4 6 2