This document discusses fluid and electrolyte balance. It begins by outlining the objectives of reviewing normal fluid composition, crystalloid and colloid solutions, and perioperative fluid management. It then discusses the fluid compartments in the body, fluid homeostasis, types of fluids including crystalloids, colloids, and blood products. It provides details on specific crystalloid and colloid solutions, perioperative fluid therapy including maintenance requirements and replacing losses. It concludes by discussing clinical evaluation of fluid replacement and management of common electrolyte imbalances such as sodium, potassium, and calcium.

1. FLUID AND ELECTROLYTE BALANCE
PRESENTER: DR SAURAV SUMAN YADAV
MS GENERAL SURGERY RESIDENT
NATIONAL ACADEMY HEALTH SCIENCES, BIR HOSPITAL
1

2. Objectives
• To review the normal fluid composition of the body.
• To understand the physiochemical and biologic properties of the various crystalloid and colloid
solutions available.
• To discuss the perioperative fluid management.
• To review about the management of common electrolytes imbalance (Na K Ca)
• To recapitulate on the clinical basis of some routinely practiced protocols.
2

3. Fluid Compartments
• Water makes up approximately 60% of total body weight.
3

4. Fluid Homeostasis
4
fluid homeostasis
Neutral balance : I = O
Positive balance : I > O
Negative balance: I < O

5. Types of Fluids
Crystalloids
1. Saline solutions
2. Balanced solutions
3. Dextrose solutions
Colloids
1. Human Plasma Derivatives – Albumin solutions
2. Semisynthetic Colloids – Gelatins, HES, Dextran.
Blood and Blood products
1. Whole blood, PCV, FFP, PRP, PC,
5

6. Crystalloids
• Electrolyte solutions with small molecules that can diffuse freely throughout the extracellular
space.
• 70% of a crystalloid infusion remains in the intravascular compartment at the end of a 20-minute
continuous infusion, decreasing to 50% after 30 minutes.
• Indicated for replacement of free water and electrolytes and used for volume expansion
6

7. Comparison of Plasma and Crystalloid Fluids
7

8. Saline Solutions : 0.9% Sodium Chloride
• One of the most commonly administered crystalloids.
• Though called normal saline, it is neither chemically nor physiologically normal.
• Infusion of one liter of 0.9% NaCL adds 275 mL to the plasma volume and 825 mL to the interstitial
volume.
• Infusion of saline leads to a hyperchloremic metabolic acidosis, reduced renal perfusion and promote
interstitial edema.
8

9. Hypertonic Saline
• Available as solutions of 1.8%, 3%, and 7.5% NaCl.
• Uses:
• Plasma volume expansion.
• Correction of hypoosmolar hyponatremia.
• Treatment of increased intracranial pressure.
• Reduce cerebral edema and intracranial pressure.
• 7.5% HTS even has immunomodulatory factors.
9

10. Ringer’s Fluids
• Advantage
• lack of a significant effect on acid-base balance
• Disadvantage
• the ionized calcium in Ringer’s solutions can bind to the citrated anticoagulant in stored RBCs
and promote clot formation.
• Can trigger immune response (neutrophilic reaction)
• Contraindicated as diluent fluids for the transfusion of erythrocyte concentrates (PRBC).
10

11. Notes
• Prefer NS when hyperkalemia, hypercalcemia, hyponatremia, hypochloremia and metabolic
alkalosis
• Avoid RL if K+ levels high
• Avoid NS if BP high
• Avoid plain 5 % D or DNS if diabetic
11

12. Other Balanced Salt Solutions
• Normosol and Plasma-Lyte
1. Contain magnesium instead of calcium.
2. Contain both acetate and gluconate buffers to achieve a pH of 7.4.
3. Less tendency to promote interstitial edema when compared with isotonic saline.
12

13. Dextrose Solutions
• D5, D10, DNS
• Uses:
• Replacement of pure water deficits
• Maintenance fluid for patients on sodium restriction
• Source of metabolic substrate
• If glucose utilization is impaired (as is common in critically ill patients), large- volume infusions of
D5 can result in cellular dehydration.
13

14. Colloids
• Contain large, poorly diffusible, solute molecules that create an osmotic pressure to keep
water in the vascular space.
• About three times more effective than crystalloid fluids for increasing plasma volume.
14
Solution Molecular
Weight
Osmolality
(mOsmol/L)
Albumin 5% 70000 300
Albumin 25% 70000 1500
Dextran 40 40000 308
Dextran 70 70000 308
Hetastarch 450000 310
Hextend 670000 307
Gelofusine 30000

15. Albumin Solutions
• Principal determinant of plasma colloid oncotic pressure
• Principal transport protein in the blood
• Significant antioxidant activity
• Heat treated preparations of human serum albumin
• 5% sol (50g/l) and 25% sol (250g/l) in 0.9% NaCl
• Albumin as less inflammatory properties than crystalloids.
• Note:Books have explained about 25%albumin solution however in practice we commonly use
20%solutions for 3 consecutive days.
15

16. 5% Albumin Solution
• Given in aliquots of 250 mL
• Plasma volume increment averages 100% of
infused volume
• Volume effect begins to dissipate at 6 hrs and
can be lost after 12 hrs
25% Albumin Solution
• Given in aliquots of 50/100 mL
• Plasma volume increases by 3 to 4 times the
infusate volume
16

17. Semi synthetic colloids
• Gelatin
• One of the firsts synthetic colloids.
• Degradation product of collagen
• Hetastarch
• Derived from amylopectin obtained from sorghum, maize, or potatoes
• Also has pro-inflammatorry effects as crystalloids
• Is specifically associated with alterations in coagulation
17

18. Crystalloids
Advantages
• Lower cost
• Greater urinary flow
• Interstitial fluid replacement
Disadvantages
• Transient increase in IV volume
• Peripheral edema (protein dilution)
• Pulmonary edema
18

19. Colloids
Advantages
• Smaller infused volume
• Prolonged increase in plasma volume
• Less peripheral edema
Disadvantages
• Greater cost
• Coagulopathy
• Anaphylactic reaction
• Pulmonary edema (capillary leak state)
• Decreased GFR
• Osmotic diuresis
19

20. Perioperative Fluid Therapy
• Vary depending on
• Patient factors, including weight and comorbidity
• Surgical factors, such as the magnitude and site of surgery
• The aims of perioperative fluid administration should be to:
• avoid dehydration,
• maintain an effective circulating volume, and
• prevent inadequate tissue perfusion
20

21. • Includes:
1. replacement of normal losses (maintenance requirements),
2. replacement of preexisting fluid deficits, and
3. replacement of surgical wound losses including blood loss.
21

22. Normal Maintenance Requirements
22

23. Preexisting Deficits
• Preoperative bleeding, vomiting, nasogastric suction, diuresis, and diarrhea are often contributory.
• Fluid shifting out of intravascular space because of burns, inflammation(as in pancreatitis)
,intestinal obstruction, infection and sepsis.
23

24. Surgical Fluid Losses
1. Blood Loss
• Monitor and estimate blood loss
2. Other Fluid Losses
• Obligatory losses of fluids other than blood
• Mainly due to
• evaporation and
• internal redistribution of body fluids (third space loss)
24

25. Replacing Redistributive & Evaporative Losses
• Primarily related to wound size and the extent of surgical dissections and manipulations.
25

26. Post operative fluids
• Aim: To maintain reasonable blood pressure (>100/70 mmhg), pulse rate <120/min, hourly urine
output of 30-50ml/hour, with normal temperature, warm skin, normal respiration and senastion.
• Intra op blood loss replaced with equal volume of crystalloid.
• Ideal is to replace volume of blood lost with three times volume of crystalloids.
26

27. When and how long to give iv fluids?
• Depends on type and duration of surgery.
• Patients subjected to short operative procedures , who don’t need handling of intestinal viscera
will only need maintenance iv fluids to correct defecit due to NPO.
• Patients with major surgeries (exploratory laparotomy,) where intestinal viscera need rest, require
post op iv fluids for few days.
27

28. 28

29. Clinical Evaluation of Fluid Replacement
• 1. Urine Output: at least 0.5 ml/kg/hr
• 2. Vital Signs: BP and HR normal (How is the patient doing?)
• 3. Physical Assessment: Skin and mucous membranes not dry; no thirst in an awake patient
• 4. Invasive monitoring; CVP or PCWP may be used as a guide
• 5. Laboratory tests: periodic monitoring of hemoglobin and hematocrit
29

30. • Lobo et al. reviewed 20 adults after elective colonic resection.
• Aggressive intraoperative fluids 20 mL/kg/hr.
• Postoperatively, randomly assigned to restrictive (< 2 L/day) or standard
protocol (≥ 3 L/day).
• Latter significant weight gain, later return of bowel function and prolonged
hospital stay.
• Lowel et al 1990
of 48 patient in SICU: 40% had >10% wt gain
related to mortality,: fluid administration significant variable
30

31. The rules of fluid replacement:
• Replace blood with blood in 1: 1 ratio
• Replace plasma with colloid 1: 1 ratio
• Resuscitate with crystalloid in shock 1: 3 ratio
• Replace ECF depletion with saline
31

32. ASSESSMENT OF IV FLUID AND ELECTROLYTE NEEDS IN SURGICAL
PATIENTS: RECENT ADVANCES
• Any patient requiring IV fluids needs assessment revolving round 4 indications for fluids, which
NICE designated as the “4Rs” and incorporated into prescribing algorithms along with a 5th R for
reassessment
• Resuscitation
• Routine maintenance
• Replacement
• Redistribution
• Reassessment

33. The Best Regimen for Routine Maintenance: NICE GUIDELINES
• NICE also reviewed studies in which surgical patients received IV fluids with chloride >120
mmol/L with those receiving fluids with chloride < 120 mmol/L1 and concluded that provision of
lower chloride fluids was probably associated with lower mortality and morbidity.
• NICE recommendation that for routine maintenance an appropriate initial prescription should
deliver approximately: 25–30 mL/kg/day of water; 1 mmol/kg/day of potassium, sodium and
chloride; and 50–100 g/day of glucose.

34. • They also recommended that less fluid (e.g. 20–25 mL/kg/day) should be considered in patients
who are older or frail and those with renal impairment, cardiac failure or malnutrition.
• Concentrated (20–25%) sodium poor albumin has been used for oedematous patients with a plasma
volume deficit, aiming to draw fluid from the interstitial space and promote renal perfusion and
excretion of sodium and water excess.

35. Electrolytes
- Maintain body fluid volume and osmolarity
- Distribute body water between fluid compartment
- Promote neuromuscular conductivity
- Regulate acid-base balance
35

36. Regulation of Total Body Electrolyte Mass and Plasma Concentrations
Electrolyte Regulated by
Sodium Total body sodium regulated by aldosterone,
ANP, [Na+] altered by ADH
Potassium Total body potassium regulated by aldosterone,
intrinsic renal mechanisms;
[K+] regulated by epinephrine, insulin
36

37. Sodium
• Principal extracellular cation and solute
• Essential for generation of action potentials in neurologic and cardiac tissues.
• Normal value:135-145 mEq/L
37

38. Hyponatremia
• Hyponatremia is defined as plasma [Na+] <135 mEq/L
• Classified as
• Mild (130 to 134 mEq/L),
• Moderate (120 to 130 mEq/L), or
• Severe (<120 mEq/L)
38

39. 39

40. Clinical features of Hyponatremia
• Acute onset (< 48 hrs):
• When at levels 120 to 125 mEq/L with headache, confusion, agitation, vomiting, and lethargy
• [Na+] < 110 mEq/L - seizures and coma
• Chronic:
• Clinical features may be absent even at [Na+] < 120 mEq/L.
• Other features include loss of appetite, nausea, vomiting, cramps, weakness
40

41. 41

42. Management of Hyponatremia
• Infusion Rate For Hypertonic Saline:
estimated by multiplying the patients body weight (in kg) by the desired rate of increase in plasma
[Na].
• For example, if the patient weighs 70 kg and the desired rate of rise in plasma [Na] is 0.5 mEq/L
per hour, the initial infusion rate of hypertonic saline is 70×0.5 = 35 mL/hr
42

43. 43

44. Osmotic Demyelinating Syndrome
• Measures recommended for avoiding osmotic demyelination:
• For chronic hyponatremia
• the plasma [Na] should not rise faster than 0.5 mEq/L per hour (or 10–12 mEq/L in 24 hours),
and
• the rapid correction phase should stop when the plasma [Na] reaches 120 mEq/L.
• For acute hyponatremia,
• the plasma [Na] can be increased by 4–6 mEq/L in the first 1– 2 hrs.
• However, the final plasma [Na] should not exceed 120 mEq/L.
44

45. Na+ Replacement
• Na Deficit = (Na Desired - Na observed) x 0.6 x body weight (kg)
• Replace half in first 8 hours and the rest in the following 16 hours
• Rise in serum Na should not exceed 10-12 mEq/L in first 24 hrs to prevent Central Pontine
Myelinolysis
45

46. Hypernatremia
• Hypernatremia is defined as a plasma [Na+] >145 mEq/L
• Less common than hyponatremia
• May affect up to 10% of critically ill patients.
• If severe ([Na] > 160 mEq/L), a 75% mortality may occur depending on the severity of the
underlying disease process.
46

47. 47

48. Management of Hypernatremia
• The first step in treating hypernatremia is to estimate the TBW deficit:
• Hypernatremia must be corrected slowly because of the risk of neurologic sequelae such as
seizures or cerebral edema.
• The water deficit should be replaced over 24 to 48 hours.
• The plasma [Na+] should not be reduced by more than 1 to 2 mEq/L/hr for the first few hours and,
if the hypernatremia has been present for more than 2 days, no more than 10 mEq/L/day.
48

49. 49

50. Potassium
• Important role in cell membrane physiology
• Generating action potentials in the central nervous system and heart
• Intracellular - 150 mEq/L,
Extracellular - 3.5 to 5 mEq/L
• Normal value: 3.5-5 mEq/L
50

51. Hypokalemia
• Hypokalemia is defined as a plasma [K+] <3.5 mEq/L
• Can be the result of K+ movement into cells (transcellular shift), or a decrease in total body K+ (
K+ depletion)
51

52. Mechanism Cause
Intracellular K+ shift ß2 agonists Lithium overdose
Insulin therapy Hypothermia
Alkalosis
Inadequate intake Anorexia nervosa
Alcoholism
Malnutrition
GI loss Vomiting
Diarrhoea
Fistulas
Excess Renal loss Mineralocorticoid excess
Glucocorticoid excess
Diuretics
Osmotic substance
Renal tubular acidosis
Bartter and Gitelman syndrome
52

53. Clinical Features of Hypokalemia
• Asymptomatic in most cases.
• Moderate-to-severe hypokalemia (2 to 2.5 mEq/L) leads to
• muscle weakness,
• ECG abnormalities ( 50% cases)
• ST segment depression,
• T wave depression,
• U wave elevation
• Prolonged QT
• arrhythmias (atrial fibrillation and ventricular extra-systoles)
53

54. Management of Hypokalemia
• Mild Hypokalemia ( K+ > 2 mEq/L )
• IV KCL infusion ≤ 10 mEq/hr
• Severe Hypokalemia ( K+ ≤ 2 mEq/L, paralysis or ECG changes )
• IV KCL infusion ≤ 40 mEq/hr
• Continuous ECG monitoring
• If life threatening, 5-6 mEq bolus
54

55. Hyperkalemia
• Hyperkalemia is defined as a plasma [K+] >5.5 mEq/L
• Can be a life threatening condition.
• Can be the result of
• potassium release from cells (transcellular shift), or
• impaired renal excretion of potassium
55

56. Drugs Promoting Hyperkalemia
Promote Transcellular Shift
• Beta – blockers
• Digitalis
• Succinylcholine
Impair Renal K+ Excretion
• ACE inhibitors
• ARBs
• K+ sparing diuretics
• NSAIDs
• Heparin
• Trimethoprim-Sulfamethoxazole
56

57. Clinical Features of Hyperkalemia
• Muscle weakness, paralysis
• Altered cardiac conduction (increased automaticity and
enhanced repolarization) with consequent ECG changes
57

58. Management of Severe Hyperkalemia
58

59. 59
Calcium Imbalances
• Mostly in ECF (ionized)
• Regulated by:
• Parathyroid hormone
• ↑Blood Ca++ by stimulating osteoclasts
• ↑GI absorption and renal retention
• Calcitonin from the thyroid gland
• Promotes bone formation
• ↑ renal excretion

60. 60
Hypercalcemia
• Total serum Calcium > 10.5mg/dl or Ionized Calcium >5.3 mg/dl
• Results from:
• Hyperparathyroidism
• Hypothyroid states
• Renal disease
• Excessive intake of vitamin D
• Milk-alkali syndrome
• Certain drugs
• Malignant tumors – hypercalcemia of malignancy
• Tumor products promote bone breakdown
• Tumor growth in bone causing Ca++ release

61. 61
• Effects:
• Many nonspecific – fatigue, weakness, lethargy
• Increases formation of kidney stones and pancreatic stones
• Muscle cramps
• Bradycardia, cardiac arrest
• Pain
• GI activity also common
• Nausea, abdominal cramps
• Diarrhea / constipation
• Metastatic calcification

62. 62
Hypocalcemia
• Total serum Calcium < 8.4 mg/dl or Ionized Calcium <4.5 mg/dl
• Hyperactive neuromuscular reflexes and tetany differentiate it from
hypercalcemia
• Convulsions in severe cases
• Caused by:
• Renal failure
• Lack of vitamin D
• Suppression of parathyroid function
• Hypersecretion of calcitonin
• Malabsorption states
• Abnormal intestinal acidity and acid/ base bal.
• Widespread infection or peritoneal inflammation

63. • Diagnosis:
• Chvostek’s sign ( Facial twitch)
• Trousseau’s sign (carpopedal spasm)
• Treatment
• IV calcium gluconate for acute cases
• Oral calcium and vitamin D for chronic
63

64. Fluids and electrolyte abnormalities in special situations
64

65. Neurologic patients
1. SIADH
Euvolemic and hyponatremic individuals with elevated urine sodium levels and urine osmolality.
• Restriction of free water will improve the hyponatremia
• Furosemide also can be used to induce free water loss.
• Chronic SIADH
• demeclocycline and lithium can be used to induce free water loss.
65

66. 2. Diabetes insipidus
• In patients tolerating oral intake, volume status usually is normal because thirst stimulates
increased intake.
Mild cases:
Free water replacement
• Severe cases:
Inj Vasopressin is 5 U subcutaneously every 6 to 8 hours
66

67. Malnourished Patients: Refeeding Syndrome
potentially lethal condition that can occur with rapid and excessive feeding of patients with severe
underlying malnutrition due to
• Starvation
• Alcoholism
• Delayed nutritional support
• Anorexia nervosa, or
• Massive weight loss in obese patients
Caloric repletion should be instituted slowly and should gradually increase over the first week
67

68. Acute Renal Failure Patients
• Hyperkalemia
• Hyponatremia
• Hypocalcemia,
• hypermagnesemia, and hyperphosphatemia
68

69. Cancer Patients
• Hypovolemic Hyponatremia
• Hypokalemia
• Hyperkalemia (Tumor lysis syndrome)
• Hypocalcemia
• Hypercalcemia
69

70. In a nutshell..
• Fluids should be considered as drugs with specific indications, cautions, dose ranges, and side
effects.
• The secret to selecting the appropriate resuscitation fluid is to ask the question—what is the cause
and severity of the hypovolemia in this patient?
• A single variable (i.e. the extracellular volume), can be used to understand, identify, and correct the
osmotic impact of hypernatremia and hyponatremia.
• Hypokalemia is remarkably well tolerated compared to hyperkalemia.
70

71. ONE LINERS
• Some advocate that hyperchloremic metabolic acidosis is not detrimental. In fact, it will shift o2
dissociation curve to right causing increased unloading of 02 to the tissues.
• Nowadays ketone ringers lactate is used BECAUSE ketone can be used as the source of energy
during energy deficient states.
• 50ml of 25%albumin is physiologically equivalent to approx 2000-2500ml of cyrstalloids.
REDUCE THE IV FLUIDS WHEN GIVING ALBUMIN.
71

72. • Every 100-mg/dL increment in plasma glucose above normal, the plasma sodium should decrease
by 1.6 mEq/L
• Adjust total serum calcium down by 0.8 mg/dL for every 1 g/dL decrease in albumin.
• If the hypokalemia is resistant or refractory to K+ replacement, magnesium depletion should be
considered. Magnesium depletion promotes urinary K+ loss.
• The most effective method of potassium removal is hemodialysis, which can produce a 1 mEq/L
drop in serum K+ after one hour, and a 2 mEq/L drop after 3 hours
72

73. • Three times volume of fluid will maintain intravascular blood volume and cardiac output but O2
carrying capacity of blood will be compromised . So blood should be arranged as soon as possible.
REPLACE BLOOD WITH BLOOD !
• If the patient has not passed urine during immediate post-op, giving diuretics has an negative
impact, as not passing urine is itself a volume conserving mechanism of our body.
• Adding thiamine before the initiation of feeding have shown to prevent refeeding syndrome
73

74. • In surgery, never consider a patient to be normovolemic, they are either hypovolemic or
hypervolemic! This has been the conservative approach.
• Patient with anasarca can also have hypovolemia due to accumulation of fluids in interstitial space
and not enough volume in intravascular space. USE CENTRAL VENOUS LINE as a guide in such
situation.
• In ICU too much intravascular volume is better than too little.
• TOO MUCH: PULMONARY FAILURE (MORTALITY: 20%)
• TOO LITTLE: RENAL FAILURE (MORTALITY :48%)
74

75. References
• Sabiston textbook of surgery
• Bailey &Love’s short practice of surgery
• Schwartz principles of surgery
75

76. 76
THANK YOU