Fluid pdf - د. اياد

Dr. Ayad Abbas

Lec. 1

FLUID & ELECTROLYTE

Tues. 23 / 9 / 2014

Published by : Ali Kareem

مكتب اشور لالستنساخ

5102

Surgery

FLUID & ELECTROLYTE

Lec 1:

23/9/2014

د.اياد عباس

Total body fluid and its distribution

 Water represents 60% of the mean body mass
 The body fluid contained in two compartments which are separated by

cell membrane and these are:

1. Intracellular compartment ICC form 2/3 of TBF.
2. Extracellular compartment ECC form 1/3 of TBF.

 Furthermore the ECC is subdivided into:

a.Intravascular 1/4 These 2 spaces are separated from each other by
b.Interstitial 3/4 endothelium of capillary wall.

 These spaces are not rigid units, but they are in constant exchange

between them to be in balance.

Transcellular fluid: fluid in CSF, aqueus of eye, vitreous of eye and GIT
secretion.

 These are ECF, but in special compartments and have rather different

function from the main mass of the body fluid and they are usually
considered separately.

* For adult 70 kg body weight.

Litres*

compartment

100%

TBF

66%

ICF

33%

ECF

25.5%

ISF

7.5%

IVF

Fat 15%

Protein 18%

Mineral 7%

ICF 40%

Interstitial 15%

Intravascular 5%

Fluid intake

Fluid intake is derived from two sources:
(1) exogenous; and (2) endogenous.

Exogenous water is either drunk or ingested in solid food.

The quantities vary within wide limits, but average 2—3 litres per 24 hours,

Taking into consideration their body weight, the water requirements

of infants and children are relatively greater than those of adults because of:

(1) the larger surface area per unit of body weight;
(2) the greater metabolic activity due to growth; and
(3)  the  comparatively  poor  concentrating  ability  of  the  immature

kidney.

Endogenous water is released during the oxidation of ingested food;

the amount is normally less than 500 ml 24 hours.
1 gm of fat → 1 ml of fluid,
1 gm of protein → 0.4 ml of fluid,
1 gm of CHO → 0.6 ml of fluid

However,  during  starvation,  this  amount  is  supplemented  by  water  released
from the breakdown of body tissues.

Fluid output

Water is lost from the body by four routes.
1 • By the lungs. About 400 ml of water is lost in expired air each 24 hours. In
a  dry  atmosphere,  and  when  the  respiratory  rate  is  increased,  the  loss  is
correspondingly  greater  (this  also  applies  to  the  patient  who  has  their  trachea
intubated).

2•By  the  skin.  When  the  body  becomes  overheated,  there  is  visible
perspiration, but throughout life invisible perspiration is always occurring. The
cutaneous  fluid  loss  varies  within  wide  limits  in  accordance  with  the
atmospheric  temperature  and  humidity,  muscular  activity  and  body
temperature. In a temperate climate the average loss is between 600 and 1000
m1124 hours.

3•  Faeces.  Between  60  and  150  ml  of  water  are  lost  by  this  route  daily.  In
diarrhoea this amount is greatly multiplied.

4• Urine. The output of urine is under the control of multiple influences, such
as  blood  volume,  hormonal  and  nervous  influences,  among  which  the
antidiuretic hormone plays a major role controlling tonicity of the body fluids,
a  function  that  it  performs  by  stimulating  the  reabsorption  of  water  from  the
renal  tubules,  thus  varying  the  amount  excreted  after  the  requirements  of  the
first  three  routes  have  been  met.  The  normal  urinary  output  is  approximately
1500  ml124  hours,  and  provided  that  the  kidneys  are  healthy,  the  specific
gravity  of  the  urine  bears  a  direct  relationship  to  the  volume.  A  minimum
urinary output of approximately 400 m1124 hours is required to excrete the end
products of protein metabolism.

Fluid Balance

Defined as a ratio between water input (through all routs) and water output
(through all routs and it is normally equal to one).

Fluid balance = fluid input/fluid output = 1

◊ If the ratio > 1→ +ve fluid balance (input > output).
◊ If the ratio < 1→ -ve fluid balance (input < output). Electrolyte distribution
in the body

Electrolyte distributed in the body compartment in different
concentration.

Electrolyte

142

145

140

< 1

110

105

HCO

HPO

-2

Protein

◊ The daily requirement of Na

= 1-2 mmol/day.

◊ The daily requirement of K

= 0.5-1 mmol/day.

Osmolarity: is a number of osmoles per liter of solution and plasma
osmolarity .
Osmolarity = 280-300

osmolarity

= 2 [Na

] + 0.055 [Glc] + 0.36 [BUN

]

=2 X 140 + 0.055 X 120 + 0.36 X 40 =300

*The 2 is for Na

+ Cl

**Blood Urea Nitrogen

◊ Movement of fluid between IC & EC depends on the tonicity
(OSMOLARITY) of ECF.

◊ ↑ tonicity of ECF → fluid shift from ICC to ECC → shrinkage of cell.
◊ ↓ tonicity of ECF → fluid shift from ECC to ICC → swelling of cell.

 Shrinkage is a dangerous effect, it have neurological, respiratory and

cardiovascular effect. It can cause Drowsiness, Confusion, Convulsion,
Coma, Shallow Breathing, Apnea, Tachycardia and Finally Stand Still.

 Swelling (Edema) also has a dangerous effect, ex: incase of CEREBRAL

EDEMA ,this edema may cause CVA (cerebro-spinal accident) which
occur due to the compression on the vessel that carry the O

and

Nutrients to the Cerebral hemisphere.

◊ As Intravascular compartment is separated from Interstitial compartment by
semi permeable membrane (permeable to electrolyte, water and glucose and
impermeable to large molecule e.g. protein).Then The movement between i.v
& i.s governed by OSMOSIS and ONCOTIC PRESSUER.

In case of Liver Cirrhosis and Nephrotic Syndrome , there will be loss

of Proteins that will lead to Decreasing the ONCOTIC PRESSUER.

Osmosis: Diffusion of solvent molecule from a region of low concentration of
solute to a region of high concentration of solute through a membrane
impermeable to that solute.

Osmotic pressure: The pressure of solution that is necessary to prevent
solvent diffusion.

Oncotic pressure: The pressure of plasma that is necessary to prevent
movement of fluid from I.V to I.S compartment. It reflect the presence of
proteins in I.V compartment.

So movement of fluid between i.v and i.s depends on 3 factors:
1.Hydrostatic pressure of i.v
2.Hydrostatic pressure of i.s
3.Oncotic pressure of i.v

= HP (vessels) - [HP (i.s) + OP (vessels)]
◊ In artery = 37- (1+25) = +11→ shift to interstitial
◊ In veins = 17 - (1+25) = -9 → shift to vein

Dilution of ECF

HyperOsmolarity

HypoVolaemia

Angiotensinogen

ADH

Baroreceptor

O retention

Angiotensin I

Angiotensin II

Osmoreceptor

In Ant.Hypothalamu

Hypothalamus

RBF

H2O

Retention

Na retention

Vasoconstriction

ADH

Aldosterone

Thirst

O Intake

ACE

Renin

Control of body

fluids and electrolytes

SUMMARY
1.Defence of tonicity:
● Hyperosmolarity             thirst
                                      fluid retension
                       ↑ADH
● Hypoosmolarity: vice versa.

2.Defence of volume:
Volume (body fluid) determined by total amount of osmoticaly active solute in
ECF  →  ;  therefore  the  mechanism  to  defense  the  volume  is  the  same
mechanism to defense the Na

Water depletion

-Pure water depletion is usually due to diminished intake. This may be due to:
lack of availability,
-difficulty  or  inability  to  swallow  because  of  painful  conditions  of  the  mouth
and pharynx,
-or obstruction in the oesophagus.
-Exhaustion  and  paresis  of  the  pharyngeal  muscles  will  produce  a  similar
picture.
-Pure  water depletion  may  also  follow  the  increased  loss  from  the lungs  after
tracheostomy.  This  loss  may  be  as  much  as  500  ml  in  excess  of  the  normal
insensible  loss.  After  tracheostomy,  humidification  of  the  inspired  air  is  an
important preventive measure.

Clinical features

The main symptoms are weakness and intense thirst.
The urinary output is diminished and its specific gravity increas-ed.
The  increased  serum  osmotic  pressure  causes  water  to  leave  the  cells
(intracellular  dehydration),  and  thus  delays  the  onset  of  overt  compensated
hypovolaemia (see below).

Water intoxication

This can occur when excessive amounts of water, low sodium or

hypotonic solutions are taken or given by any route. The commonest cause on
surgical wards is the overprescribing of intravenous 5per cent glucose solutions
to postoperative patients. Colorectal washouts with plain water, instead of
saline, have caused water intoxication during total bowel wash-through prior to
colonic surgery. A major component of the TURP (transurethral resection of
the prostate) syndrome is the water intoxication caused by excessive uptake of
water (and glycine) from irrigation fluid.

Similarly, water intoxication can occur if the body retains water in

excess  to  plasma  solutes.  This  can  be  seen  in  the  syndrome  of  inappropriate
antidiuretic  hormone  (SIADH)  secretion  which  is  most  commonly  associated
with  lung  conditions  such  as  lobar  pneumonia,  empyema  and  oat-cell
carcinoma of bronchus, as well as head injury.

Clinical features

These include drowsiness, weakness, sometimes convulsions and

coma. Nausea and vomiting of clear fluid are common, and, with the notable
exception of the SIADH, usually the patient passes a considerable amount of
dilute urine. Laboratory investigations may show a falling haematocrit, serum
sodium and other electrolyte concentrations.

Treatment

The intake of water having been stopped, the best course is water

restriction. If the patient fails to improve, transfer to an intensive care or high
dependency unit will be necessary for more invasive monitoring and controlled
manipulation  of  fluids  and  electrolytes.  The  administration  of  diuretics  or
hypertonic  saline  should  not  be  undertaken  lightly  as  rapid  changes  in  serum
sodium  concentration  may  result  in  neuronal  demyelination  and  a  fatal
outcome.

Types of fluids used for mangment:

1- Crystaloid: (Isotonic – Isoosmolar):

a- Normal Saline contain NaCl 0.9 ٪
b- Glucose Water cntain glucose 5 ٪(inside the body glucose enter cell and

the I.V become hypoosmolar).

c- Glucose Saline conatin NaCl and glucose and according to the ٪of NaCl

called ½ , 1/3 and 1/5.

d- Ringer solution and ringer lactate contain NaCl, K

, Ca

, HCO

and

lactate.

2- Colloid Fluids: (Hyperosmolar):

Contain large particles that cannot pass through the semi-permeable
membrane that separate the I.V compartment from I.S compartment.
Dextran 40, Dextran 70, Hemacel, Jel Fusion, Albumin.

These fluids should not be given for more than 1 L.

Complication of these Fluids:
1- Diluted Thrombocytopnea.

2-Interferce with Cross Match.
3- Anaphylactic reaction.

the 2

and 3

complications are especially of Dextrans.

Suggested Routin Postoperative Fluid Regime,

taking in account the

body response to Trauma “SURGERY”:
1- In the 1

24 hours after surgery (zero day of operation): the patient requires

no salts and less water than normal requirement , so 2 liters of 5 ٪dextrose
is enough.

2- In the 1

and 2

Post-Operative Day: the metabolic response to surgery

diminishes and the patient requires 2 liters of 5 ٪dextrose and 1 liter of 0.9 ٪
normal saline.

3- In the 3

Post-Operative day and thereafter 0.5-1 mmol/kg of KCl is add to

fluid per 24 hours.

Printed by :

Ali Malik

Special greetings to: Marwan Zuhair, Mohamed Esam, Sabah Nasir,

Yasir Kasim and to Zaid Fareed