PHYSIOLOGIC MECHANISMS

n.e...

~~

...

p/>y&iok>g>< ..., ... i .n" 111M ... '" I1Ili nlain fl uid and ol<ctrolyte

~ •. Some Df IIIese ..., ... , ... "" .... upcnd",,,,,, of ''''''ZY. aDd - . do noI. \\'br"", ... ,. i, I di""~iocI in III)' Df IIIese meduoni ... ' ...

it ;. b<aotoo of III " " ' . . . dItonic i l ' - .

,II<

<Od><qU<fICC i. "'"' nuid aDd .krtroI)'t< ~ "di ..

,,,,,,,!.

Cilpill.;lIy- 'ntlfstitium Ftuld ExtIl'r19'

FIuOd....,.... """" ... y beno'mI

,II<

capOII)' """" ... '"l<nIitiaI >pitt.

Thi. i. poWbI< ~ ... Ilory &h_ """"""' ... nuid from .... .-.pi113ry ID .... iII ... u ... botn> nopolbry COP ... ftuod t.ck i .. " .... .-.piliOf)'. In

><IdiOOoo I D . -.-.pilbry. iacIoccd """""""' ... hod """""'" .. ,,,,,," .... inoootil"m

"I'P""'" .-.piliOf)' ~ttr.t..,., """""",. IIId i ... MoaI COP ""III nuod , _ ....

iII""';oW ~. In~.

-mat

<Omp<>llllM:. Df _ ,,'illMn .... eopillary and iII""';liaI ~ i.

"""""'Y.o ... ,.

.hII ... fton:e. .. """" ... Iibri ...

n..

moot , .. , . , _ nu .. Df d""'lu,lobrium 1><1 ... fon'a io I dd'eim<y of :oIbumtn in ... 1 .. "",,".

Albumin

Albumin and .... ,Lobuli . . and fibri""l"n ~.I1< ....

it><

proIei ... foond in pi...,..

and ... """ "'" «>I1o<1" .. ly ,.form! 10 ... p/<l""" p",,~j

....

Albumin ; ... main d.tonnin:,,", of COP. I..., ,",'or 75 pc",e" Df COP .. "",inl.inc:d by albumin."

n.. .. r"", . ..

rum album,n level. n,." be ., Ie .... , ,he bwcr 000 Df nonn:oI for

"""""I COP '" be mointo,ntd. In S ... I •• """""I .. rum .Ibumin .... ,,1 in odul ..

i. J.S_S.1l mgldL .0<1 rOl" child"'n i, 4.~,<J mgluL," If ><",m .Ibumin level. "'"

i<N", Ih>n

-mat .•

<:<><>di'ion ,.rorred tu II ~}'p"«I"","in,,"ia. lhen ,.pillory COP canno< be ""'in'alntd. ond Huid

"'1'"

;n«, , ... in""",,;ul1l, Thi. may """It in Hui<!

""en'ion in .... I ... and ""eilh, gain. IlthouSh ,hi. I.;n in "".ish' ",H<rtI goin in fluid Dthe, 1lwI. !OIn ,n mu><1e

m.u.

^Of rat..",.,.,

Sl2n':1lion and ~ of oppropiMe .... Itio .... <tlOII<TOIIy ""'" hypoalbuminemio.

In oddi,ion. ocule ... "' a """""'" nu ... Dunna bma of .. YIe " ' -"'1leih«1he

... »<11" "' • di>r_ '" .. inJUry. Ihc 1,,,,," manur ... 1.ft5 ' ' ' ' ' ' ' ' _ ... <If

..-..e.

""""' _ I J'I'O'<' .... i""I\ldLna

"""P1<menI

and pmn'IO llobub .... in

oru..- '"

""""" .<1<f ... Ihc Ihn:. oflhc -....-.

A,. tuuIt. ....

~

.... ....,. _

be able '" ""';n", '" ... r ... ouffi<ient quant"", of olbumin. 11oi> pI ... , .. _, ..

rri<fTftllD .. /oq>tJtiL" ,.."nt>ntQJs_ ond poruaIly.,.plains .. -hy <:riti<ally iU ~ 1ft II""",

at."Y'

h)pooolbu"" ... ond • mt ('" Auod .-..bon in Ihe

-...w

~.'

1-. .,.".

triIw:-.Ily ill potIM .. may"" .... "'><Iopacl.yil<1llic ftk .... '"

.... nlMl "'"' obey .,.hi.". WI"'" i, rri<fTftlID ... ho-...lo""*,,,," _~'

" I.V. Therapy Demystified

Becau", .Ioomin plays weh > ley role in m.intaining COP. it i. used freqoently as . colloid l.V, the~ to 're" l"'ienlS who .... critically ill 0< ,,'ho ... a .ignificant nUlri'KlnaI <kne". of"'" with mired re,"ils. 1'1 ... refor to

a.. pI<!

^{8 for}

a further di",u,sion of .Ibumin I. V. Ihe",py.

Thirst (enter

1he thirst ""nle •. which i. 1oc>100 in the hypolhal.mus, "'!l"lo'e. fluid hal""" •.

Speci.hzed ""uro'l< ",ferred to as O,""'"UP'OTS "'""" ""rum osmol.Ii,y. >nd when it ;"""'''''' •. reflecting dehydration. thi .... is .. imulated. 1he

,hi",

<enter 01"" <.n he triUered indirectly by b2r0recep''''' that are !"" ..

..t

in la'lle , . ..,.,\s weh as Ih<

aonic arch and the carotid.,

n.e",

barorecepl"" are ",,,,;,i,,,, to pre .... re '" .trelch and are triggered by a decr .... in blood volume.'

K idneys

1he renal ,ubul •• in the kid""y' nn ""lecti,..,ly reabsorb or diu", .. water and e"'troIyte. as r.eedcd to moln,ain fluid ",Iume botaoc., 1he ", .. I tubule. respond to """,r.ll differen, IJl<"Chanism •. Fir>! of .11. in lhe p .. ",e,,,,. of \ow oxygen "n,ion that lesults from either> low hen»globin 1 .. 01 or. deer.ase in blood "']UIDe. the j""~glomerular ",,11. within the kidney. prOOoce the hormone renin. R<rIin .... "'"

.lfeet of oool'ming a reloti, .. ly i""n pi", .... prot.in coiled IllIgiofnuinog<n to angi""'n,in I, When angiotensin I enten the pulmonary v ... l., circuit. it meeu

angi""'n,in~<>I .... ning enzyme. which """""n. it to angK>t<n'in II, AngKltonsin II

< ... ')"Iomic v:o>oconstriction. re,ulting in "n ioc", ... in .ystemic anerial bkod pre"ure. ond it influe""". the ",nal tubul •• ",that sodium ,nd .... ter.re re.b>orbed.

1he .If ... of angioten.in II are rel>li.,.ly shon_li"ed; _ .. ,or. it .1oo "imul ....

"'" >dr.n.1s to reI""", .Idosterooe. Aldosterone ... imilar .If ... to angKltensin II. inclnding • Iy,..,mi< iocre"", in bkod pre"u", throogh it> ,...oron>trictive .If ... , Moree,or. it 01", e""oo~. the ren.1 tubul., to re.bsorb more >Odium ond

",,,ter, I" effoets ... looger_lived th.n tho>e of ,ngiot.",in 11.'

Antfdiuretic Hormone

Antidiureti< hormone (ADH) arr ... "'" renal tubule. dirertly so that i""re>Sed reabsorptK>a of .. 'ator """u", ADH i •• hormone that i. ,tored .nd rele>Sed by "'"

posterior portion of the pituitory gl.nd. other,..i .. <.IINthe Murompoph~',i,. when it is stimulatN by the thi'" ",n",r in the hypoth.l"",u" k noted pre,ic .... ly. "'"

thi,,' ""nter responds to input from ",moreeepl"". ,,'hi<h ore particularly receplive '0 .ubtle <hang •• in serum ",moWi'y ond '0 inpu' from """,ul., b.roRCeplOO-S.

which. in tum, .re ""'pli,.., to aru'" <hang"' in bkod volume,'

CHAPTER 2 fluids and ElectroLytes

"

FLuid Tonicity

t:.

11><

_ ,vl.

Hwd i. 'kmllhII .. r"'lOlhe~ityof.Ooid>p<rimrn.

Osmolality n. mnsun: of ~lIy .... " .. ponicleo ... !" .. n.oo.;.,., f .... unit of ... 11>< mojonty of _ """",.,.Uy ... "" pa,tid . . . ~1rctroIJ'<'.

Spocifi<::dly. _",iry ori ... ", rIM: oomoIal~y of. " ... ft"od .. _ _ .d "irb ....

"""""'-"ltyof .... K:F vl. ""II .... I ... ,,',Ilua. pool of IhII ftOMCl 11>< dfKUofECF

~ity "" ",,110 • daspIoyed ,., F.,. 2-2 - ' •

eli"""""'" ,.,

rile IoIk",,';,,«...-tiom.

'-

.-'.';." .'

..

^;

':: .

.

^'

",

: ,:~--

--, " , '

, ,

.'

.'-

"-. -. ^,:

, , ~

.. '.

-,-. ,:

',',-. ".' ^{. . .} " .-::

^-'.:

, ... "-'.'.',:."

.~

,-... z·z """"

tilt <'If ... 0(

_ y

^{of _ _ ..} ""I", "-CrlI< pIo<od . _

"'_.-ain _

^B. Cdl>pIo<od 10 ^h)~ ... _ _ ... _ irItra:dIDlor _ >nil

_at:.

^{C Cell<} po<..alo bYl"*"*" - . .... '" pia_1DII<b irlrrI'rihllor _ >nil • .-ril (iIopWed _.,..,.,... _ _ .... TI. H _ AG:

~

<f -.,..,...,.,-

C-.,.tt"

Afr"'" . t- _ c ....

P..f-"-'.

!..r «l _ ",CJIIM<:()nw·I~II. 1999".0(19 )

I.V. Therap y Demystified