Fluid

1. FLUID AND ELECTROLYTES
Afolabi akinwale ibrahim

2. INTRODUCTION
• Fluids are important for viability of cells
• It is the medium for all metabolic reactions.
• Appropriate regulation is essential for survival
especially in response to stress or disease
conditions.
• Closely linked to management of blood
products , acid-base balance , shock and
nutrition

3. BODY FLUID COMPOSITION
• Total body water ;50-85%
• Depends on age , sex , body fat
• Body mass=fat+h20+minerals+protein+glycogen
• Intracellular-40%
• Extracellular -20%
• I intravascular -4%
• ii extravascular
• I, transcellular 1%,interstitial 15%
•

4. ELECTROPHYSIOLOGIC BASIS
• ELECTROPHYSIOLOGY OF EXCITABLE CELLS
• Resting membrane potential
• Stimulus results in depolarization [sodium enters
,potassium leaves cell] , to threshold potential
,action potential amplitude ,re-polarisation.
• Amplitude of action potential is reduced by
hyponatraemia
• Hyperkalaemia leads to less negative resting
membrane potential making cell more excitable

5. ELECTROLYTE
DISTRIBUTION[mmols]
ION INTRAVAS INTERSTITIAL INTRACELLULAR
sodium 140 143 8
potassium 4 4 140
Ionised calcium 1.25 0.625 1
magnesium 0.7-0.9 0.75 15
chloride 95-105 115 8
bicarbonate 24-27 30 14
phosphate 0.8-1.4 1.6 25.8
protein 2 0 9
sulphate 1 1 20
Organic acid 3 3 0

6. NET COMPOSITION OF GI SECRETIONS
Type Vol[ml/day] Naa[meq/l] K[meq/l] Cl[meq/l] Hco3[meq/l
]
Stomach 1000-2000 60-90 10-30 100-130 0
Small int. 2000-3000 120-140 5-10 90-120 30-40
Colon -200 60 30 40 0
Panreas 600-800 135-145 5-10 70-90 95-115
Bile 300-800 135-145 5-10 90-110 30-40

7. ELECTROLYTE LOSS
SODIUM Tropics [ mmols] Temperate [mmols]
Urine 114 80-110
sweat 10-16 -
faeces 10 10
TOTAL 130-140 90-120
POTASSIUM
Urine 50 60
sweat - -
faeces 10 10
TOTAL 60 70

8. ELECTROLYTE REQUIREMENT
Age Na[mmols/kg/day] K[mmols/kg/day]
Premature 3-4 1-2
First four days of lfe 2 1-2
Adults 2-3 1-2

9. WATER LOSS
Water lossess Tropics temperate
Pulmonary/cutaenous 1700mls 1000mls
urine 1500mls 1500mls
faeces 200mls 200mls
TOTAL 3400mls 2700mls

10. WATER REQUIREMENT
• 50mls per kg
• 100mls per kg for first 10 kg
• 50 kgmls per kg for next 10kg
• 20 mls per kg for subsequent kg
• About 45-50 mls /kg
• 12% increase for every degree temperature rise
• Ventilation
• Room tempearature
• humidity
• Loss per 100 calorie
• Insensible-45ml,urinary-50mls,stool 5mls

11. REGULATION OF SODIUM
EXCRETION AND WATER VOLUME
• Bp—rbf---gfr—
• Renin[b adr, red. Perfu, red. Na load]—
[ace]angiotensinogen ---angiotensin1 ---angiotensin 2
[vasoconstrictor]aldosterone[na exchange with k and h]
• Endogenous creatinine clearance depends on muscle mass.
Not too dependent on diet like urea
• Adh and osmorecetors
• Bp ---aortic arch,carotid sinus[baroreceptors]—
catecholamines –sympathetic nervous system
• Atrial natruiretic peptide
• Intravascular fluid—capillary membrane—interstitial fluid --
-cell membrane—intracellular fluid

12. INVESTIGATIONS
• Serum electrolytes
• May lag behind very acute deficits
• na , k , hco3, ca , mg, urea , creatinine ,u/cr ratio
low in low protein diet or liver disease.
• Serum protein [total,albumin , globulin]
• 24 hour urine creatinine
• Urine electrolytes
• Na , k ,specific gravity .
• Full blood count , -packed cell volume
• Liver function tests

13. INVESTIGATIONS
• Chest xray
• Ecg
• Echo-cardiogram
• INVASIVE
• Urethral catheterisation .adult 0.5-1mls/kg
,neonate 1-2ml /kg
• Central venous pressure
• Pulmonary capillary wedge pressure

14. • SERUM OSMOLALITY
• Normal 282-295mosm/L
• 2x[na+k] +BUN/2.8 +glucose /18
• Panic values <240 >321

15. TOTAL BODY WATER DEFICIT
• DEHYDRATION
• Loss of water
• CAUSES
• -gastrointestinal loss[ vomiting , NG tube
aspiration , diarrhea , enterocutaenous fistula
, git secretions ]
• -excessive sweating , polyuria , fluid shifts eg
burns

16. CLINICAL FEATURES OF DEHYDRATION
• SUBJECTIVE
• Thirst , history of loss , nausea , muscle
weakness , altered mental state
• Objective
• Sunken eye ball , reduced skin elasticity , GCS
,dry tongue ,vital signs
• Collapsed veins , capilary refill

17. CLASSIFICATION OF DEHYDRATION
Dehydration Deficit calculation
Mild[2-5%] 50 x wt
Moderate[5-10%] 100 x wt
Severe[10-15%] 150 x wt

18. CORRECTION OF DEHYDRATION
• Correct deficit[1/2 in first 8 hrs, next half in
16 hrs]
• Stop lossess
• Replace on going losses
• maintainance

19. TOTAL BODY WATER EXCESS
• FLUID OVERLOAD
• Extremes of age , over aggressive resuscitation
• Particularly in hypoproteinaemia , cardiac ,
renal , hepatic disease
• CLINICAL FEATURES
• Worsening clinical state , dyspnoea ,
tachycardia,tachycardia , distended JVP ,

20. CLINICAL FEATURES OF WATER EXCESS
• History of cause eg SIADH , iatrogenic ,
• Usually background renal , cardiac or hepatic
impairment
• Cardirespiratory
• -respiratory distress ,tachycardia , heart failure
,raised JVP wheezes , pulmonary congestion
[crepitations]
• Neurologic
• -especially with hyponatraemia eg altered
sensorium ,seizures.

21. TREATMENT OF WATER EXCESS
• TREATMENT
• -prevention
• Nurse in cardiac position , oxygen
• MONITORING
• JVP, peripheral and pulmonary oedema
• Chest for crepitations
• Monitor weight
• Iv frusemide , ethacrynic acid , mannitol

22. HYPONATRAEMIA
• Decreased ECF volume-gi, renal lossses, diuretics
,red. Intake[urine Na<20meq/l]
• normal ECF volume-hyperglycaemia,SIAD,water
intake,diuretics
• Increased ECF volume[dilutional] –increased
intake , SIAD,tricyclic antidep,,ace inhibitors ,post
op.
• Pseudo-hypo Na. extreme elevation in plasma
lipids/proteins

23. • CLINICAL FEATURES
• Depends on absolute level and rate of decline
• <120meq/l confusion
drowsiness.<110mmeq/l seizures , coma
• Features of dehydration in volume depleted
• Sodium deficit =wt x 0.6 xideal-real serum na

24. • CNS-headache, confusion, red/incr deep
tr,seizures , coma, raised ICP
• MSS- weakness , fatigue , cramps,/twitching
• GI-anorexia, nausea , vomitting, watery
diarrhoea
• CVS-hypertension,bradycardia[raised icp]
• Tissue – lacrimation , salivation
• Renal –oliguria

25. • Replace volume in volume depleted with
normal saline or ringers lactate
• Stop drugs
• Hypertonic saline..may cause central pontine
myelinolysis
• Iv mannitol

26. SYNDROME OFINAPPROPRIATE
ANTIDURESIS
• Due to ADH incr or sensitivity.a cause of hyponatraemia
• Low output of concentrated urine[>100mosm/kg h20]
.increased urinary excretion of sodium[>40 meq/l]
,decreased plasma osmolality[<275mosm/kg h20]
• Usually euvolaemia, no recent diuretic use, normal thyroid ,
adrenal function
• CAUSES
• Post op, positive pressure ventilation ,myxedema, adrenal
cortical deficiency , bronchogenic carcinoma, pancreatic
carcinoma, pneumonia , lung abscess, pulmonary tb , head
injury , brain tumor , meningitis , opiods ,

27. CEREBRAL SALT WASTING
• Inapproprite natriuresis[negative salt balance]
• with volume depletion and signs of
dehydration , unlike SIAD
• Due to intracranial disease

28. HYPERNATRAEMIA
• High volume –iatrogenic administration,
mineralocorticoid excesess , CAH , cushings
disease, HYPER-aldosteronism[urine
Na>20meq/l] , urine osmolarity>300mosm/l]
• Normal volume-non-renal water loss[ skin GI]
,renal water loss renal disease , diuretics ,
diabetes insipidus
• Low volume-non-renal water losss[skin, GI] ,
renal water loss , renal tubular disease , DI,
adrenal failure , osmotic diuretics[urine Na <15 ,
meq/l urine osmolarity >400mosm/l]]

29. • CLINICAL FEATURES
• Symptomatic usually in patients wit impaired
thirst
• thirst , dizziness, fainting attacks
• Dry mouth , dry skin , reduced skin turgor ,
collapsed peripheral veins , tachycardia ,
hypotension

30. CLINICAL FEATURES
• CNS- restlessness , lethargy , ataxia, irritability
, tonic spasms , delirium , seizures , coma
• MSS-weakness
• CVS- tachycardia , hpotension , syncope
• Tissue- dry , sticky membranes , decr. Saliva
/tears
• Renal – oliguria
• Metabollic- fever

31. DIABETES INSIPIDUS
• Decreased or absent ADH
• Volume deficit with passage of large volume of urine with
low osmolarity sg < 1.003, <200mosm/l and hypernatremia
• Central - brain tumor , head injury , meningitis
• Nephrogenic –hypokalaemia , hyper calcaemia , chronic
renal disease ,lithium , colchicine.
• Treatment –
• increase water intake
• desmopressin
• ADH enhancing drugs[chlorpropamide,hydrochlorothiazide

32. POTASSIUM
• Important for cell exitability
• 2%[about 50-60mmol] of total body store of
3150mmols is in ECF
• Hypokalaemia commoner than hyperkalaemia

33. HYPERKALAEMIA
• Causes ;
• Increased intake Blood transfusions Ascidosis , endogenous load/
destruction tumor lysis syndromme ,extensive trauma
suxamethonium administration in burns
• Increased release in ascidosis , rapid rise of extrcellular osmolality
• Impaired excretion , renal insufficiency/ failure , potassium sparing
diuretics ,ACE inhibitors , NSAIDS
• Clinical features
• GI- nausea ,Vomiting ,colic , diarrhoea
• MSS- weakness
• CVS-arrhythmia, arrest
• Ecg;tall t waves , absent p waves , widened qrs interval ventricular
arrhythmias , fibrillation , cardiac arrest

34. TREATMENT OF HYPERKALAEMIA
• Stop causative agent
• Protect the heart -Sodium bicarbonate,calcium
gluconate
• Drive potassium into cell -Dextrose infusion
• Insulin
• B 2 agonist[ nebulised salbutamol]
• Enhance potassium excretion
• Ion exchange resins
haemodialysis

35. HYPOKALAEMIA
• Causes
• Potassium decreases by 0.3meq/l for every 0.1 increase in PH above
normal
• May be due to magnesium depletion
• Inadequate intake ,potassium fee iv fluids/ tpn
• Excessive excretion -hyperaldosteronism
• GI lossess , diarrhoea , ng tube ,enterocutaenous fistula .
• Clinical features
• GI –ileus , constipation
• MSS-Weakness , lethargy ,fatigue, decreased reflexes
• CVS- arrest
• ECG-depressed st segments, flat or inverted t waves , u waves ,

36. POTASSIUM CORRECTION
• Potassium correction
• Stop loss
• Citrus fruits , milk
• oral
• Adequate urine output
• Ecg monitoring
• k<40mmols/litre and <20mmol/ hour
<.25meq/kg/hr

37. CALCIUM
• Found in skeletal mass , muscle
• Dietary intake about 1-3 g/day mainly excreted
• Vit d , parathyoid hormone , calcitonin
• <1% in ECF
• 40% Bound to protein [inactive form], 10% complexed
to phosphate and other anions, 50% ionised
• Free ionised form is physiologically active
• For every 1g/l tahat albumin is >40g/l subtract .02
• For every 1g/l that albumin is less , add 0.02

38. • Acidosis reduces calcium binding to protein
thus increase free ionised calcium
• GUIDE LINES TO TAKING SERUM CALCIUM
• -fasting , morning sample , lying supine , no
exercise , no tourniquet , serum albumin also
taken.

39. HYPOCALCAEMIA
• Hypoparathyroidism ,parathyroid injury post thyroidectomy
vit d deficiency , calcium chelators in blood transfusion,
pancreatitis, renal fialure , pancreatic and small bowel
fistula, malignacies associated with increased bone
formation , , in hyperphosphataemia
• Cns . Numbness, circumoral paraesthesia , confusion ,
seizures
• Cvs-hypotension , non specific qt intervals
• Muscle weakness ,fatigue, chvostek sign , trousseaus sign
• ECG-prolonged qt interval , t wave inversion , heart block,
ventricular fibrillaton
• Treatment
• Calcium gluconate , calcium chloride

40. HYPERCALCAEMIA
serum calcium above normal range[8.5- 10.5meq/l], ionised calcium
above normal range [4.2-4.8mg/dl]Hyperparathyroidisms , skeletal
metastases , immobilised patients
• CNS-Sedation ,confusion,coma vommitting ,
• RENAL-polyuria ,renal stones
• GI- abdominal pain
• MSS-Weakness, bone pain
• CVS-hypertension , arrhythmia
• Prolonged pr interval , wide qrs complex , shortened qt interval ,t
wave flatening and widening ,atrio-ventricular block
• Treatment
• Hydration, diuresis , mithramycin, biphosphonates

41. MAGNESIUM
• Mainly intracellular
• Total body content 1000-2000meq.
• 50-60% in bone
• 1/3 of ECF is bound to albumin

42. HYPOMAGNESAEMIA
• CAUSES
• May lead to hypo calcaemia and hypo kalaemia
• Increased loss- Chronic alchoholism , malabsorption , pancreatitis
• inadequte intake –alchoholism , starvation , if fluid therapy ,
enterocutaenous fistula
• Features similar to hypocalcaemia Cns irritability -hyperreflexia ,
seizures
• Muscular irritability-muscle spasm
• ECG- prolonged QT and PR interval , ST segment depression , pwave
flattening or inversion
• Treatment
• Magnesium sulphate

43. HYPERMAGNESAEMIA
• CAUSES
• Iatrogenic is commonest cause eg mgsulphate
• Severe renal insufficiency
• CLINICAL FEATURES
• CNS depression , hyporeflexia
• CVS depression,hypotension
• MSS weakness
• ECG- similar to hyperkalaemia .increased PR interval,
widened QRS complex , tall t waves
• Treatment
• Prevent dehydration and ascidosis
• calcium

44. PHOSPHOROUS
• Largely intracellular
• HYPERPHOSPHATAEMIA
• CAUSES decreased urinary excretion[impaired
renal function] ,
• increased intake- tpn , laxatives
• or endogenous mobilisation –rhabdomyolysis
,tumor lysis syndrome ,hemolysis , sepss,
malignant hyper thermia
• Mainly asymptomatic or due to deposition of
calcium/phosphte complexes

45. • HYPOPHOSPHATAEMIA
• CAUSES
• Decreased intake-malabsorption , malnutrition
• Intracellular shifts-respiratory alkalosis , refeeding
syndrome , insulin therapy ,hungry bone
syndrome
• CLINICAL FEATURES
• Decreased high energy phosphates leading to
weakness.

46. ROUTES OF ADMINISTRATION
• Intra-osseous[mainly children]
• Intraperitoneal
• intra-rectal
• Subcutaenous
• COMMONLY
• GIT ; oral , naso-gastric/naso -duodenal/nasojejunal
pharyngostomy ,cervical esophagostomy , gastrostomy ,
jejunostomy
• Intravenous [crystalloid/colloid]
• KNOW HOW TO SET UP IV LINE
• KNOW DRIP Rate

47. COMPOSITION OF CRYSTALLOIDS
FLUID Na k ca cl hco3 glucose osmolari
ty
Ringers L 130 4 4 111 27 276
N/S 154 154 308
5%dx in
ns
154 154 50 586
4.3% dx
in 1/5
saline
30.8 30.8 43
darrows 124 36 104 56 320
3%
saline
513 513 1026

48. • Hypertonic saline
• Dextrose infusions 5%,10% ,50% dex water

49. COLLOIDS
• Have higher molecular weight substances .
• Ideal
• Not toxic , not stored in body, non pyrogenic ,
allergenic or antigenic
• No interference with blood grouping and cross
match or other serum investigations , immune
function , coagulation , acid base balance

50. TYPES OF COLLOIDS
– Ratio 3:1 crystaloid:colloid
– Blood
– TYPES OF COLLOIDS
• Plasma protein
• Albumin [5,25%]
• Dextran
• Gelatin colloids[haemacel ,gelofusine
• Hydroxyl starch [hetarstarch , pentastarch

51. COMPOSITION OF COLLOIDS
SOLUTION Mol. wt osmolality sodium
Haemacel 35000 300 145
Albumin 5% 70000 300 130-160
Albumin 25% 70000 1500 130-160
Dextran 40 40000 308 154
Dextran 70 70000 308 154
Hetarstarch 450000 310 154
Hextend 670000 307 143
Gelofusin 30000 - 154

52. SIDE EFFECTS OF COLLOIDS
• Anaphylactic reaction
• Interfers with blood group and cross match-
dextran
• May cause coagulopathy—dextran[fc vii]
• Limited volume of use
• Easily causes fluid overload

53. Complications of intravenous infusion
• Thrombophlebitis
• Septicaemia
• Air embolism
• Fluid overload
• Hyperchloremic acidoss[NaCl]
• Metabollic alkalosis [ringers lactate]

54. CONCLUSION
• Fluid and electrolytes management is one of
the key principles of pt management in clinical
practise
• Constant monitoring is essential .

55. Reference text
• Schwarts principles of surgery –ninth edition
• Principles and practise of surgery –fourth
edition
• Postgraduate surgery second edition