1. APPROACH TO FLUID , ELECTROLYTES AND ACID BASE DISORDERS
DR.S.SHIVAKUMAR
PROF.OF.MEDICINE
STANLEY MEDICAL COLLEGE & HOSPITAL

2. INTRODUCTION: Hyponatremia is a very common disorder
Fluid & Electrolytes can occur as single or multiple disorders
Hyponatremia is a very common disorder
Pottassium disorders can be life threatening
Acid base disorders common in ICU & medical wards
Choice of fluid therapy should be appropriate
Treat individual disorders, but should be combined in multiple disorders.

3. APPROACH: Acidosis Alkalosis
Disorders of volume Volume depletion Fluid overload
Dysnatremia - Hyponatremia / Hypernatremia
Dyskalemia Hypokalemia / Hyperkalemia
Acid base disorders
Acidosis
Alkalosis
Metabolic/ Respiratory
Metabolic / Respiratory

4. CLINICAL APPROACH: CLINICAL FEATURES:
Volume depletion Skin turgor loss / Hypotension
Volume excess Oedema / HT
Hyponatremia/ Hypernatremia CNS Manifestations
Hypokalemia Muscle weakness
Hyperkalemia Cardiac arrythmias
Metabolic acidosis
Respiratory alkalosis
Hyperventilation

5. + - MULTIPLE DISORDERS: Disorder DKA Diarrhea ARF Diuretics Volume Na+
M.Acidosis + -
M.Alkalosis

6. SINGLE DISORDERS:
Disorder
SIADH
Methanol poisoning
Periodic paralysis
Volume N
Na+ K+
ABG
Acidosis

7. FLUID & ELECTROLYTE HOMEOSTASIS
Regulation of Volume (Na+) Na GFR Renin Angiotensin Aldosterone Renal retention of Na+
ECF Volume is regulated by Na.( BP & Interstitial volume)
2.Regulation of Osmolality ( Water)
H2O Osm ADH Kidney retains H2O
ICF Volume is regulated by osmolarity of plasma.
Normal plasma osmolarity = mOsm/L
Calculation= 2(Na + K)+ Sugar/18+Urea/6
Ratio of Na+ to H2O decides plasma osmolality.
3.Regulation of Acid Base:

8. VOLUME & OSMOLALITY DISORDERS:
Volume Disorders: Only clinical signs (PNa+- Normal)
Volume depletion ECF Na+ loss ( Diarrhea,Diuretics )
Volume excess Na Retention( Cardiac failure, renal failure)
Osmolar Disorders:- Plasma Na+ altered.
1. Water Excess Hyponatremia (SIADH)
2.Water depletion -- Hypernatremia ( D.Insipidus )
Volume & Osmolar Disorders: (Clinical & Altered P. Na+)
Volume depletion & Water excess – ECF Na loss & H2O retention / Hyponatremia ( Diarrhea & 5%GDW)
Volume depletion & excess water depletion - Na < H2O loss / Hypernatremia (HONK )

9. 20% (ECF) 40% (ICF) Normal Total body sodium determines ECF Volume.
INTRACELLULAR
VASCULAR (4%)
Interstitial (16%)
Total body sodium determines ECF Volume.
Plasma Na determines ICF volume.
Plasma osmolarity (PNa+) determines fluid movement into cell.

10. Volume depletion (ECF )
Normal PNa+
INTRACELLULAR
Loss of skin turgor
Hypotension
40%
10%
Eg: Diarrhea, Vomiting & Diuretics
Total body Na loss leads ECF volume depletion.
No change in plasma Na.

11. Volume excess (ECF ) 30% 40% edema HT
Normal PNa+
30%
40%
edema
INTRACELLULAR HT
Eg: Cardiac failure,Nephrotic syndrome, Renal failure & Cirrhosis
Increased total body Na leads to ECF volume excess.
Plasma Na normal

12. Hyponatremia (ICF ) 45 % 20% Eg: SIADH
INTRACELLULAR
PNa+
20%
Eg: SIADH
Increased ADH Increased total body H2O leads to decreased plasma Na ( Osmolarity ) Increased ICF due to shift of H2O from ECF to ICF.

13. Hypernatremia (ICF ) 20% 30% PNa Eg: D.Insipidus
INTRACELLULAR
Eg: D.Insipidus
Polyuria Pure water depletion Decreased body H2O leads to increased plasma Na ( Osmolarity)
H2O shifts from ICF to ECF.

14. Volume depletion & Hyponatremia (ECF & ICF )
45 %
Hypotension, skin turgor loss, Drowsiness
INTRACELLULAR
H2O
PNa
10 %
Na +
Eg: Diarrhea, replaced by 5 % GDW
Total body Na decreased by Diarrhea
Increasaed H2O retention due to 5 % GDW ( Plasma Na low)
ECF volume depletion + Increased ICF volume

15. Volume excess & Hyponatremia ( ECF & ICF )
25 %
45 %
INTRACELLULAR
H2O
edema
& P Na +
Eg: Cirrhosis + 5 % GDW
Cirrhosis leads to increased total body Na & ECF
Excess H2O leads to decreased plasma Na & increased ICF

16. 30 % 10% Volume depletion & Hyperosmolarity ( ECF & ICF ) Osmolarity
INTRACELLULAR
Osmolarity
Na+
H2O
Eg: Hyperosmolar Non- Ketotic syndrome ( DM)
Polyuria of DM leads to ECF volume depletion ( H2O> Na)
Increased plasma Glucose leads to hyperosmolarity & ICF depletion
Plasma Na can be Normal OR High ( Instead of being low)

17. Why do we need fluids? FLUIDS --- Healthy individuals Sick patients:
---Regulation of temperature --- loss by sweating
---Excretion of waste products -- Renal / GI
1.5 – 2.5 L / Day
Salt – 5 gm / day
Sick patients:
1.Replacement for losses --- GI losses – Vomiting / Diarrhea
--Renal losses -- DKA / Diuretics
-- Skin loss – Burns / sweating
2.Maintenance for daily requirements

18. Concentration of ions in IVF (In Meq/L) Solutions Glucose(gms) Na Cl K Ca
Lactate
5%GDW 50
10%GDW
100
20%GDW
200
5%GDW/0.9%NaCl
154
5%GDW/0.45NaCl 77
0.45%NaCl
0.9%NaCl
3%NaCl
513 RL
130
109 4 3 28

19. Concentration of ions in IVF (Poly-ionic fluids) Solutions Na K Cl
Glucose Na K Cl
Acetate
HPO4
NH4
Isolyte-M 50 40 35 20 15
Isolyte-E
140 10
103 47
Isolyte-G 63 17
150 70

20. DISORDERS OF VOLUME

21. Volume depletion Isotonic volume depletion Diarrhea Vomiting
Hypotonic volume depletion
Hypertonic volume depletion
Diarrhea replaced by H2O
D.Insipidus
HONK
DKA
Excess sweating
PNa
H2O > Na loss
PNa-Normal
Na+ = H2O loss
PNa
H2O < Na loss

22. Correction: Body weight: Volume depletion: 0 - 8 hrs Choice of fluids:
ISOTONIC VOLUME DEPLETION:
Causes - vomiting / Diarrhea
Assess severity - mild / moderate
/ severe
Body weight:
5 %- mild : skin turgor loss / dry Tongue
5 % - 10 % : Mild + postural hypotension
10 % - severe: moderate + hypotension
Correction:
Volume depletion: hrs
0- 1 hrs --- shock
1- 8 hrs -- rest of calculated fluids
8- 24 hrs -- maintanance fluids & concurrent losses
Choice of fluids:
Diarrhea RL
Vomiting % NaCl

23. A 50 year old male is admitted for severe diarrhea of 3 days duration
A 50 year old male is admitted for severe diarrhea of 3 days duration. He is drowsy & has loss of skin turgor & dry mouth. BP: 80 / 50 mmHg.Lungs are clear.
Urea : 72 mg% S.Cr : 1.7 mg% Na+ : 122 meq/L
K+ : 2.6 mg%
Ph: 7.2 pCo2 : 32mmHg pO2 : 100 mmHg
HCO3 :12 mmHg
Problems:
Severe volume depletion
Hyponatremia
Hypokalemia
Metabolic acidosis
Azotemia- prerenal

24. 50 year Individual ( 50 kg)
Severe Volume depletion % - 5 L
Diarrhea – Na, K, HCO3 loss
Replacement fluids - RL
0-1 hr – 1 L ( Treatment of Shock)
1- 8 hr – 4 L
Maintanence fluid + concurrent loss : 1.5 – 2.5 L ( Hrs)
Decreased Na – Corrected by Volume correction
RL – Lactate HCO3 in liver

25. Treatment -- HONK / DKA – 0.45 % NaCl D.Insipidus ---- 5 % GDW
Hypertonic volume depletion ( Volume depletion & water depletion - PNa )
Na < H2O Depletion
Pure H2O depletion
Extrarenal
Insensible losses
Renal DI
NDI
Extra renal ( sweating)
Esp.pt not taking oral fluids
Renal loss
DKA
HONK
Salt losing nephritis
Treatment -- HONK / DKA – 0.45 % NaCl
% NaCl + 5 % GDW
D.Insipidus % GDW

26. DYSNATREMIAS

27. Hyponatremia Hypovolemia Euvolemia Hypervolemia Diuretics Diarrhea
Post-operative
SIADH
Drugs
CNS & Pulmonary diseases
(Menstruating women)
CCF
Nephrotic syndrome
Cirrhosis

28. Hyponatremia Symptoms: Symptomatic Asymptomatic Chronic ( > 48 hrs)
Acute < 48 hrs
Symptoms:
CNS: Cerebral edema -- Headache, Drowsy / coma / Seizures.
Lab: PNa < 135 meq/L

29. Management Symptomatic Hyponatremia
Treatment: Emergency: 3 % NaCl ml/ kg/ hr with co-administration of Furosemide
STRATEGY: Removal of H2O
Furosemide: Natriuresis -- Na + H2O
Replace Na with 3 % NaCl – Excretion of H2O
Urine output > fluid intake

30. Treatment objectives:
Asymptomatic Hyponatremia: ( Euvolemia& Hypervolemia)
1.Water restriction : < 1L / day
2.Demeclocycline – 600 mg / day
3.Identify & treat the causes
Hypovolemic Hyponatremia:
IV Fluids -- NaCl / RL
Treatment objectives:
Gradual correction of PNa
Perform serial neurological examination
Perform serial Serum Na & Urine Electrolytes & osmolality

31. A 60 year old male a known case of Bronchogenic carcinoma is admitted for seizures. He is unconscious & his volume is normal
Urea : 28 mg % S.Cr : 0.8 mg % Na+ : 110 meq/L K+ : 4.6 meq/L
Ph: 7.4 Pco2 :40mmHg HCO3: 24 mmHg
PROBLEMS:
1.Volume status -- normal
2. Na+ -- Hyponatremia ( Euvolemia)
3. K+ --Normal
4. ABG-- Normal
TREATMENT: 3 % Saline & Furosemide

32. Clinical features : CNS Manifestations
HYPERNATREMIA
Hypovolemic hypernatremia
Hypervolemic hypernatremia
Euvolemic hypernatremia
DKA,HONK
Excess sweating
Decreased fluid intake
Peritoneal dialysis (Hypertonic fluids)
Diabetes Insipidus
Clinical features : CNS Manifestations
Lab: PNa > 150 meq/L

33. Treatment: Hypovolemic Hypernatremia :
% NaCl
-- 5 % GDW
-- Oral fluids
Euvolemic Hypernatremia: 5 % GDW Oral fluids
Hypervolemic Hypernatremia: Dialysis

34. DYSKALEMIAS

35. Hypokalemia : K + < 3.5 meq/ L
Causes
Metabolic alkalosis
Vomiting
Diuretics
Normal Ph
-Periodic paralysis
Metabolic acidosis
Diarrhea
RTA
Treatment of DKA
Diagnosis:
Serum K+ : 3 – 3.5 meq/L - Mild
2.5 – 2.9 meq/L – Moderate
< 2.5 meq/L -severe

36. Complications: Muscle weakness -Respiratory failure
Cardiac arrhythmias
Hepatic encephalopathy
Paralytic ileus

37. TREATMENT: Non- urgent situations: Not to exceed 10 meq/hr
IV KCl : 15 % solution cc = 2 meq/L
Add to 0.9 % NaCl solution
KCl 10 ml = 20 meq/L
20 ml = 40 meq/L
Non- urgent situations: Not to exceed 10 meq/hr
In urgent situations: 40meq/Hr
Oral solution:
10 % KCl solution ( 15 ml =20 meq/L) Diluted in juice
80 – 120 ml / day
KCl should be given for 10 – 14 days

38. HYPERKALEMIA: Causes: Management:
Renal failure
Drugs -- ACE Inhibitors, Beta-bockers, spironolactone
Diagnosis: 1. ECG , 2. Serum K+ Measurement ( > 5 meq/L)
Management:
1. Calcium Gluconate: ml of 10 % solution, acts immediately, action lasts for only 30 mts
2. Insulin- 10 units / Glucose – 50 gms, acts in 15 – 30 Mts, effective for several hours
3. Sodium Bicarbonate: 50 – 150 ml of 7.5 % NaHCO3
4.Cation ion exchange resins: Na.Polysterene sulphonate (oral/enema)
5. Dialysis

39. ACID BASE DISORDERS

40. ABG Disorders: Diagnosis – Ph, HCO3, Pco2 1. Check validity
2. Obtain minimal diagnosis
3. Is it a single or mixed ABG disorder
4. Determine Anion Gap
5.Is it a triple ABG Disorder

41. Obtain minimum diagnosis
Look at pH - Acidosis / Alkalosis
Match the Pco2 or Hco3 - Metabolic / Respiratory
Disorder
Primary Change
Secondary change
Net effect
M. Acidosis
 Hco3
 Pco2
 pH ( H+)
M.Alkalosis
 Hco3
 Pco2
 pH ( H+)
R. Acidosis
R. Alkalosis

42. Examples of Simple DisorderpH
Hco3
Pco2
Metabolic Acidosis
7.15 8 24
Respiratory Acidosis 30 90
Metabolic Alkalosis
7.7 36 48
Respiratory Alkalosis 12 10

43. Is it a simple or mixed Acid-base disorder?
Simple Disorder :
Disorder
Example
Metabolic acidosis
DKA, Renal failure, Lactic acidosis, Methanol poisoning, Diarrhea,RTA
Metabolic alkalosis
Vomiting, Diuretics, Steroids
Respiratory acidosis
COPD
Respiratory alkalosis
Psychogenic hyperventilation, Hepatic Encephalopathy

44. Mixed Disorder Situation Disorder Respiratory acidosis COPD + Vomiting
+ Metabolic alkalosis
COPD + Diarrhea
+ Metabolic acidosis
Sepsis
Metabolic acidosis
+ Respiratory alkalosis
Cirrhosis + Diuretics
Respiratory alkalosis

45. Apply Compensation Metabolic Acidosis Pco2 should  by 1.2 mm
for each 1 mEq  plasma Hco3
Metabolic Alkalosis
Pco2 should  by 0.6 mm
for each 1 mEq  plasma Hco3
Acute
Resp.Acidosis
Plasma Hco3  by 1 mEq / L
for each 10 mm  Pco2
Chronic.
Resp. Acidosis
Plasma Hco3  by 4 mEq / L
Acute.
Resp. Alkalosis
Plasma Hco3  by 1 mEq / L
for each 10 mm  Pco2
Chronic
Resp Alkalosis
Plasma Hco3  by 4 mEq / L

46. Example – COPD & Diarrhea
pH : 7.00 Pco2 = 32 Hco3  = 8
Fall in Hco3 = 24 – 8 = 16
Compensatory
Fall in Pco2 = 16 x 1.2 = 19
Anticipated Pco2 = 40 – 19 = 21
Estimated : Pco2 = 32 (Pco2  )
Diagnosis
Mixed - Metabolic acidosis + Respiratory acidosis

47. Mixed acid base disorder
Compensation PH
Metabolic Acidosis + Respiratory Acidosis
eg: COPD + DKA
PCo2  & Hco3 
for simple disturbance
pH = PCo2 
Hco3 
Metabolic Alkalosis+ Respiratory Alkalosis
eg: Cirrhosis + Diuretics
PCo2  & Hco3 
pH = PCo2 
Hco3 

48. Mixed acid base disorder
Compensation PH
Metabolic acidosis + Respiratory alkalosis
eg : Sepsis
PCo2  & Hco3 
for simple disturbance
Normal or
slightly  or 
(N) pH = PCo2 
Hco3 
Metabolic alkalosis + Respiratory acidosis
PCo2 & Hco3 
(N) pH = PCo2 
Hco3 

49. Examples of mixed acid base disorder
Data
Disorder pH
Hco3
Pco2
Po2
6.85
15 (30) 90 50
Respiratory acidosis
+ Metabolic acidosis
7.3
45 (30)
+ Metabolic alkalosis 6
12 (22)
100
Metabolic acidosis
+ Respiratory alkalosis
7.75 40
25 (43)
Metabolic alkalosis

50. Determine the Anion gap
AG = Na+– (Hco3  + Cl )
Normal = 12 ± 4 ( 8  16 )
Valuable in
Metabolic acidosis – High gap / Normal gap
Metabolic alkalosis – Evaluation of “Starting Hco3”
High gap acidosis : AG > 27 mEq /L
17  26 Suggestive
eg. – Ketoacidosis, Lactic acidosis,
Methanol intoxication, Renal failure
Normal gap acidosis – Diarrhea, RTA

51. AG in metabolic alkalosis
Valuable in diagnosis of Triple disorder
(Metabolic acidosis,Met.alkalosis & Resp. acidosis)
Delta () AG =
Calculated Anion gap – Normal Anion gap
Hco3 +AG = Starting Hco3
Starting Hco3 > 29 suggests associated Metabolic Alkalosis in the presence of Metabolic Acidosis

52. Example Na+ = 135 Hco3 = 4 cl  = 90 pH = 6.8
AG = Na  ( Hco3  + cl ) = 135 – (4 + 90)
= 41  High gap acidosis
AG = Calculated – AG Normal
= 41 – 12 = 29
Starting Hco3 = = 33 mEq / L
Starting Hco3 > 29 suggests associated Metabolic Alkalosis in the presence of Metabolic Acidosis

53. Approach with an Example
A 50 year old male suffering from COPD & vomiting is admitted for breathlessness.
Biochemical parameters
pH – 6.8
pCo2 - 22
pO2 - 60
Hco3- 3.4
Na+ 135
k – 6.0
Cl- - 90
urea-110
S.Cr. – 3.0
sugar-100

54. pH = 6.8 Pco2 = 22 Hco3 = 3.4 Step 2: Obtain minimum diagnosis
Step 1 : Check Validity
H = 24 X Pc02 = 24 X 22 = 155 nEq / L = pH(6.8) HCo3 3.4
Step 2: Obtain minimum diagnosis
pH = 6.8 Pco2 = 22 Hco3 = 3.4
 Metabolic acidosis

55. Estimating the H+ ion from pH
7.0
7.1
7.2
7.3
7.4
7.5
7.6
7.7
7.8
100 80 62 50 40 32 25 20 16
 1.25
X 0.8
Within narrow limits
0.01 change in pH ~ 1 mEq / L change of [H+]
7.40 = 40
7.39 = 41
7.38 = 42
7.37 = 43

56. pH = 6.8 Pco2 = 22 Hco3 = 3.4
Step 3:
Is it a Simple or Mixed Acid base disturbance
By applying compensation
(24  3.4 = 20.6 ;  1.2 = 24.7; 40  = 15.3)
Predicted Pco2 = 15.3, but Observed Pco2 = 22
Mixed disorder
Metabolic Acidosis + Respiratory Acidosis

57. pH = 6.8 Pco2 = 22 Hco3 = 3.4 Determine Anion Gap Step 4:
Na = Cl = Hco3 = 3.4
AG = 135 – ( ) = 41.6
High Gap acidosis

58. pH = 6.8 Pco2 = 22 Hco3 = 3.4 Is it a triple disorder
Step 5:
Is it a triple disorder
Look for metabolic acidosis with AG
AG = Calculated AG - AG normal
= = 29.6
Starting Hc03 = Hco3+ AG
= = 33 mEq /L (Metabolic alkalosis)

59. Diagnosis Triple Disorder = Metabolic acidosis +
pH = Pco2 = 22 Hco3  = Po2 = 60
Na+ = k + = Cl = 90 Urea= 110
S.Cr = 3mg/dl Sugar = 100 mgs
Triple Disorder = Metabolic acidosis +
Resp.acidosis + Met.alkalosis
Metabolic acidosis – Renal failure
Respiratory acidosis – COPD
Metabolic alkalosis – Vomiting

60. Example –1
A 40 yr old man is admitted for diarrhea & breathlessness for 2 days.
pH - 7.2
pCo2 - 32 pO
Hco3- 12 Na
k - 2.9 Cl
urea-70
S.Cr
sugar-110
Diagnosis: Normal AG Met.Acidosis (AG – 11)
Due to Diarrhea + Hypokalemia,

61. Example –2 Due to Renal failure + Hyperkalemia
A 40 yr old man is admitted for diarrhea of 1week & breathlesness of 1 day
pH - 7.1
pCo2 - 20 pO
Hco3- 6 Na k Cl
urea-120
S.Cr
sugar-110
Diagnosis: High gap Acidosis (AG - 29)
Due to Renal failure + Hyperkalemia

62. EXAMPLE 1: TREATMENT b)Dialysis CONSERVATIVE MANAGEMENT IVF- RL (OR)
IV Saline ( 400 ml) + 75 ml NaCO ml KCl
EXAMPLE 2:
a)Treat Hyperkalemia
b)Dialysis

63. Example –3 (Predicted pCo2 – 18, but observed pCo2 – 12)
A 45 yr old female is admitted for high fever & breathlessness, diagnosed to have acute Cholecystitis
pH - 7.3
pCo2 - 12 pO
Hco3- - 6 Na
K+ - 5 Cl
Urea-45
S.Cr
Sugar-120
(Predicted pCo2 – 18, but observed pCo2 – 12)
Diagnosis: Metabolic acidosis + Respiratory Alkalosis Due to sepsis
TREATMENT: Treat Sepsis

64. Example –4
A 50 yr old Pt., a known case of COPD is admitted for severe diarrhea pH
pCo2 - 40
pO2 - 50
Hco3- 9 Na
K+ - 4 Cl
Urea-45
S.Cr
Sugar - 128
(Predicted pCo2 – 25, but observed pCo2 – 40)
Diagnosis: Respiratory Acidosis (COPD ) +
Metabolic acidosis (Diarrhea)

65. Example –5
A 50 yr old, known COPD Pt. with Cor pulmonale on treatment with Frusemide and is admitted for severe vomiting. pH
pCo2 - 80
pO2 - 40
Hco Na K Cl
Urea-45
S.Cr
Sugar- 128
(Predicted pCo2 – 54, but observed pCo2 – 80)
Diagnosis: Respiratory Acidosis (COPD ) +
Metabolic Alkalosis (Vomiting + Diuretics)

66. EXAMPLE 4: Ph-6.9 – Lifethreatening Acidosis
Metabolic Acidosis – IV NaCo To raise HCO3
Respiratory acidosis- Ventilatory Support To lower PCO2
EXAMPLE 5: Ph – 7.4
Treat conservatively
Metabolic Alkalosis- IV Saline + KCl
Stop Diuretics
Respiratory Acidosis – O2 Therapy
- Ventilatory support

67. Example –6
A 50 yr old Pt. with Cirrhosis Liver is admitted for coma & Vomiting. He has been treated with Frusemide recently for ascites. pH
pCo2 - 30
pO2 - 80
Hco Na K Cl
Urea - 45
S.Cr
Sugar -110
(Predicted Hco3 – 20, but observed Hco3 – 40)
Diagnosis: Respiratory Alkalosis (Cirrhosis ) +
Metabolic Alkalosis (Vomiting + Diuretics)
TREATMENT: Stop Diuretics + IV Saline with KCl
Treat Hepatic Encephalopathy

68. Summary Suspect the diagnosis from history
Suspect the disturbance from physical symptoms
Assess volume status to determine fluid therapy
Determine P.Sodium to determine water intake
Measure K+ levels & Utilize ECG to determine cardiac effects

69. Evaluate routine laboratory date :
Sugar, RFT, LFT, Na+, K+
Establish the cause of Acid Base disorder
(Utilize thoughtful differential diagnosis)
Direct management of underlying disorder,
unless pH is in a dangerous range

70. Thank You