1. Perioperative Fluid Management
DR. PRAMILA BAJAJ
SR. PROF. & HEAD
DEPTT. OF ANAESTHESIA, ADDITIONAL PRINCIPAL, RNT MEDICAL COLLEGE, UDAIPUR (RAJ.)

2. Perioperative Fluid Management
Fluid & electrolyte management paramount in surgical patient.
Change in Fluid (Fl.) & Electrolyte (El.) Composition
Pre.op
Post op.
In response to trauma and sepsis

3. Distribution of Body Fluids
Helps us understand the subject.
Total body water : 50-60% of total body weight.
Relationship constant for an individual; reflection of body fat.

4. Distribution of Body Fluids
Water in muscle & solid organs > Water in fat & bones  young, lean adults – greater% of TBW than elderly / obese.
Av. young adult male : 60% water of TBWt
Av. young adult female : 50% water of TBWt, b/c of high adipose / fat.
Estimates of TBW  Up by 10% in malnourished
Down by 10-20% in obese.
New born infants : 80% water of TBW  Decreased to 65% by 1 year, then constant.

5. Fluid Compartments Total Body Water - Extracellular Fluid (20%);
Intracellular Fluid (40%),
TBW – ECF = ICF

6. Normal Water Balance How body maintains its water volume?
Kidneys : A major role.
Oral / iv fluids & urine output : Important parameters of body fluid balance.

7. Insensible fluid input = 300 ml water due to oxidation
insensible fluid loss = 500 ml through skin (400 ml through lung & 100 ml through stool)
Fluid loss – Fluid input = 1000 – 300 ml = 700 ml
Insensible loss  in : Fever, Hypermetabolism, Hyperventilation
Sweating : Active process : Loss of electrolytes & water
1. Moderate sweating : 500 ml
2. Severe Sweating
High fever
3. Burns
Abd. Surgery
1000 – 1500 ml ml

8. Normal Water Balance …………
Kidney must excrete about ml urine / day (irresp. of oral intake)
Daily Sodium intake : 3-5 gm/d.
Balanced achieved by kidneys :
In hyponatremia : Salt excreted <1 mEq/d
In Salt wasting kidneys: >5000 mEq/d.

9. Composition of Fluid Compartments
ECF compartment : Balance between electrolytes
ECF ICF
Principal Cation : Na+ K+, Mg2+
Principal Anion : Cl- & HCO3- Phosphate & Prot.
ATP driven
Na K Pump
ECF ICF
Conc. grad.

10. Imp. Points to Remember :
Proteins : important contributors to Osmolality
Movement of water across compart. is free but that of proteins and ions restricted.
Even distribution of water in all compartments.
Sodium confined to ECF because of osmotic & eIectrolyte properties
Sodium containing fluids  distributed in ECF  Vol. of IV and interstitial sp. as much as 3 times of plasma.

11. Definitions
What is Osmotic pressure?- Movement of water across C.M. depending primarily upon osmosis.
- Determines distribution of water among different fluid compartment. (ICF & ECF)
generated by solution proportional to no. of particles / unit volume of solvent.
does not depend upon type, valence and weight of the particles
To generate O.P.  Solute must be unable to cross C.M.
Unit  osmoles (osm) or milliosmoles (mosm).
E.g.. : One mmol of Nacl  2mosm (one each from Na+ & Cl-)

12. Define Osmolality, Effective Osmolality & Osmolarity
Determined by amt. of solute diss. in a solvent (water) measured in wt (kg)
Determinants: Conc. of sodium, glucose, urea (BUN)
Calculation :
Serum osmolality = 2Na+ + Glucose BUN
Osmolality of ECF and ICF b/w Osm in each compartment

13. 3. Effective Osmolality
Determined by solutes which do not freely permeate cell wall and hold water within ECF
Effective Osmolality = 2xNa (mEq/L) + Glucose (mg/dl)/18
Glucose accounts for only 5 mOsm/kg in effective osmolality.  plasma Na concentration is the determinant of the plasma osmolality.
4. Osmolarity : Determined by amt. of solute dissolved in a solvent (water) measured in vol. (litre).
Concentration of solution of a solute diss. in 1 litre of solvent is expressed as mOsm/L.

14. Univalent ion (Sodium) ; 1 Meq = 1 Mmol
Concentration of Electrolytes : Expressed in terms of chemical combining activity or equivalents.
Univalent ion (Sodium) ; 1 Meq = 1 Mmol
Bivalent ion (Mg) ; 2 Meq = 1 Mmol
Equivalent of an ion =
Atomic Weight (gm)
Valence

15. Paediatric Surgery How are infants and children different from adults?
Fluid Management : A critical element in paed. surgery b/c infants & children sensitive to even small degree of dehydration Higher requirement for water & electrolytes / KgBw.
Inability to excrete water load due to immature kidneys  Overload.
Complex surgical procedures Rapid change in fluid requirement Frequent assessment and modification of fluid therapy.

16. Paediatric Surgery …………
In O.T. rapid change in req. during:
- Conduct of Anaesth. & Surg.
- Change in temperature
- Metabolism & vol. shift (due to trauma, hemorrhage, tissue exposure)  Intracompartmental fluid shift
Requires fluid replacement with sol. to compensate for energy, water, protein & electrolyte losses.
Anaesthetist : Alert for - obvious fluid loss
- Hidden fluid loss (insensible loss)
- Third Space loss

17. Physiological Considerations
Proportion of ECF/ICF change with age.
Body cells, surrounding fluid in electrical equilibrium
TBW Vol. & Fluid exchange rate vary
with age.
Before birth, nutrition demands met through placental transfer. NFT infant - enough fluid reserve to last till full oral breast feed.

18. Physiological Considerations … …..
TBW
Fat
28 wk (1kg)
80% 1%
Term
70-75%
17%
ECF (30-40% of TBW)  gradual shift
3 mths (6kg)
70%
30%
Further  in ICF; ECF<ICF
1 Year
60%
ECF  to 27%

19. Intravascular Plasma Vol. Together contribute Interstitial Fluid Vol.
Immature Infants : Higher% of TBW and ECF Total blood volume of a newborn infant 8.5% of B.W.
ECF
Intravascular Plasma Vol.
Together contribute
Interstitial Fluid Vol.
Functional Extracellular Fluid Vol. [FEFV]
ECF also includes III space / transcellular fluid which is physiologically non-functional

20. Interstitial Space fluid filtered
High cir. vol. : Vas. Comp.  interstitial sp. (reservoir)
Low cir. vol. : Interstitial sp.  Vas. comp.  buildup
circulatory vol.
Adolescence: FEFV 27-30% [Inter. space vol. + Plasma vol.]
20% %
Full term infant : FEFV 45%

21. What is the importance of transcellular (III Sp.) fluid?
Non functional extracellular fluid
Unavailable pool of water  formed by transudation from cells and EC space
E.g. Fluid within GIT formed during-
Int. Obst.
Ascitis
Urine
Pleural effusion
Fluid in III space loss
from FEFV
Fluid preferred for replacement : Ringer lactate

22. Intracellular Fluid
Isotonic Solution  Cell Vol. constant due to free movement of water from within cells
Hypotonic Solution  Inward water movement  Increased cell volume
Intracellular fluid bound to protein
Energy required for Potassium (inside cell) & Sodium transport (outside cell).

23. Describe the renal physiology in neonates.
Postnatal shift in body fluid med. by Na+ and H2O excretion by immature kidneys.
Sodium and water excretion by immature kidneys  Postnatal: Mediated by shift in body fluid
Urine Vol.  1st day – 0-68 ml
7th day – ml
At birth GFR 25% of adult rate (20 ml min m-2)
Rapid  in 2 wks; slower  to adult rate by 2 yrs of age
Infants can handle twice the (N) vol. load b/c -ve effects of low GFR compensated by +ve effects of low concentrating & high diluting capacity
Add conc. capacity of infant well below adult.

24. Renal Physiology in Neonates …….
Concentrating capacity : (Max. osmolality
(well below adults) Osm/kg) in response to water
Adult : (1200 mOsm/ kg)
Diluting capacity : low in dehydrated infants
If water loaded  diluting capacity well above adults (Osmolality mOsm/kg)
Fasting newborn (72 hours)  Minimum elevation of BUN & Na. (Loss of BW 13%).
8% decrease in BW; Neg. N2 balance even when fluid given at 50ml/kg/day/ or unlimited amt. of breast milk.
Milk feed  Positive N2 balance & weight gain
Wilkinson et al. 1962, Lancet 1983

25. Electrolyte Physiology
Sodium Physiology : Variable therefore inaccurate indicator of hydration.
Daily requirement (Term infant)  2-5 meq kg-1 day-1
Term infants retain Sodium when in negative Na balance like adults.
 cap. to excrete Na when in positive balance.
Ac. change in balance  Gross variation in blood pressure, Intracerebral hemorrhage.
PPV & use of PEEP  ed Natriuresis, ed vasopressin, ed water retention

26. Daily Electrolyte Requirements for Paediatric patients
Patients wt >10 kg
Patients wt <10 kg
Sodium
meq
2-5 meq/ kg
Potassium
meq
2-4 meq/ kg
Acetate
meq -
Chloride
Calcium
5-20 meq
0.5-3 meq/ kg
Phosphorus
4-24 meq
meq/ kg
Magnesium
meq/ kg

27. What are the special features of CVS physiology in infants?
Immature myocardium & S.N.S.  Propensity to hypovolaemia greater in neonates / infants.
[Myocardial contractility + vas. tone & compliance]  less variable  tachycardia  Pri. comp. mech. during  vol.
Excess  HR  C.O. 
Anaesth. effect  Further depression of myocard.  Hypovolemia exaggerated maintenance of effective vas. vol. in paed. patient essential to sustain circulatory function and vital organ perfusion in peri-op. period.

28. Hepatic Function Hepatic function immature
Carbohydrate reserves accumulate in last TM of pregnancy : limited stores in pre-term neonates.
Most pre-term neonate : Require 10% dextrose infusion to prevent hypoglycemia in early perinatal period.

29. Hepatic Function ………. Clinically significant hypoglycemia :
Full term neonate : < 30 mgdl-1
Pre term infant
First 3 days  < 20 mgdl-1
After 3rd day  < 40 mgdl-1
Treatment : Ac. hypoglycemia : Bolus g/kg-1 iv glucose followed by infusion 5-6 mg kg-1 as maintenance infusion
Monitor serial blood glucose.

30. Hepatic Function ………. Response to surgical trauma :  Catechol.
 glucocort.
 blood glucose.
Hypoglycemia : - Unusual during preop. fasting in children
- Uncommon during surgery.
- Not easily recognized during anaesth.
Dextrose in patient with prolonged fast prevents ketosis,  protein catabolism post operatively.
Continue glucose inf. commenced in OT until patient awake and oral intake established.

31. What are the fluid management protocols in infants ?
Divided into 3 phases :
Deficit therapy
Maintenance therapy
Replacement therapy
Deficit Therapy : Management of fluid / electrolyte loss prior to surgery :
Three components
Estimate Severity of dehydration
Determine fluid deficit
Repair the deficit

32. Assessment of dehydration severity in neonates & infants
Signs & Symptoms
Mild
Moderate
Severe
Weight loss
3-5%
6-9%
>10%
General Condition
Alert, restless
Thirsty, lethargic
Cold, sweaty, limp
Pulse
N. rate, vol
Rapid, weak
Rapid, feeble
Respiration
Normal
Deep, rapid
Ant. Fontanelle
Sunken
Very Sunken
Systolic pressure
Normal or low
Low, unrecordable
Skin turgor
Decreases
Markedly 
Eyes
Sunken, dry
Grossly sunken
Mucus membrane
Moist
Dry
Very dry
Urine output
Adequate
Less, dark
Oliguria, anuria
Capillary refill
< 2 sec
> 3 sec
Estimated deficit
30-50 mg/kg
60-90 ml/kg-1
100 ml/kg

33. Fluid Management ….…. History, Clinical and Evaluation Important
Confirmation by :
Serum osmolarity and serum sodium
Acid-base status, Serum pH, Base deficit
Serum Potassium compared with pH
Urine Output [To rule out ATN]
Hyponatremic Dehydration : Serum Osmolarity
<270 m.Osmol-1
Serum Na+ <130mEq/L

34. Fluid Management ….…. Isonatremic Dehydration : Serum Osmolarity
Serum Na mEq/L
Hypernatremic Dehydration : Serum Osmolarity
>310 m. Osmol-1
Serum Na+ >150 mEq/L
Initiate treatment for deficit before investigation available
Initiation with a bolus of NS over min to improve circulation and restore renal perfusion

35. Fluid Management ….….
Patient with known contraction alkalosis : 50% dextrose with 0.9% NS (Reasonable fluid of choice)
Patient with known met. acidosis : 250 ml of 0.9% NS + 28 ml of 7.5% Soda bicarbonate solution ml of 5% dextrose.
This gives approx. Dextrose 1.2%
Sodium 149 mEq
Chloride 115 mEq
Sod. Bicarbonate 25 mEq

36. Fluid Management ….….
Lactate / Acetate containing solution aggravate met. acidosis because of failure of formation of bicarbonate from its precursors due to poor circulation status.
Febrile response to volume contraction – Due to decrease in skin blood flow  Decrease heat dissipation.
Hyperosmolarity  Increased threshold for sweating  Increase calorie and fluid requirement

37. Fluid Management ….…. Fluid deficit due to overnight fasting :
Advocated to prevent risk of pul. aspiration during anaesthesia
Children :  residual gastric vol.,  pH; Clear fluids allowed upto 2 hours before surgery.
[Sphinter W.M. 1990: Anaesth Intensive Care 18: ]
Sips of fluid :  peristalsis but no gastric secretion if protein absent.
H2 blockers :  gastric pH,  gastric vol.
Sertherland AD et al. 87, Can J. Anaesth

38. Fluid Management ….…. Current recommendations : Clear fluids : 2 hours
Milk : 4 hours
General Rule :
Preop. Fluid deficit = Maint./hr. x Hrs of fluid restriction
Before Surgery
50% in 1 hour
25% each in next 2 hours

39. Maintenance fluid requirements in neonates & infants: Daily and hourly
Age (d) / Wt (Kgs)
Requirements : ml/kg-1 day-1
Hourly : mlkg-1hr-1
Type of fluid 1
20-40
2-3
10% dextrose 2
40-60
3-4
10% dextrose in 0.22% saline 3
60-80
4-6 4
80-100
6-8
5-10% dextrose in 0.22% saline
0-10 kgs
100
4 mlkg-1hr-1
5% dextrose in 0.45% saline
10-20 kgs
mlkg-1
40 ml+2 mlkg-1hr-1
> 20 kgs
mlkg-1
60 ml+1 mlkg-1hr-1

40. Composition of commonly used intravenous fluids
Electrolytes (meqL-1) NS
Ringers lactate
Isolyte P
Plasmalyte A D5
Albumin 5%
Hetastrach 6%
Na+
154
130 26
140 -
145±15 K+ 4 21 5
<2.5 Cl
109 98
100
Mg++ 3
Acetate 24 27
Lactate 28
Glucose (gm%)
Phosphate (mg%)
Osmolarity (mOsmL-1)
308
274
295
252
330
310

41. Maintenance Fluid Therapy
Meets ongoing fluid & electrolyte demands during surg.
Does not include blood loss / third space loss into gut or interstitial space.
Maintenance Fluid covers:
- Insensible loss [evaporative loss]
- Urinary loss
Insensible loss  Solute free loss of water through skin & lungs, usually 30-35% of total maint. req.

42. Maintenance Fluid Therapy
Determinants of Insensible loss :
Ambient Temp. Humidity
Gest. Age Resp. pattern
Exposed surface area
Ventilation with humidified gases   insensible loss.
In premature infants and patients with D. insipidus  Obligatory production of dil. urine  Appropriate  in maintenance fluid required.
In excess ADH secretion  Patients unable to  urine osmolality to 300 mOsm need to  vol. of maint. fluid
Gastroschisis

43. Intravenous fluid requirements in Infants
Day 1 of life 2 ml/kg per hour
Day 2 of life 3 ml/kg per hour
Day 3 of life 4 ml/kg per hour
Intravenous fluid requirements in children
<10 Kg 10 ml/kg per day
10-20 Kg 1000 ml + (50 ml/kg per day for each kg over 10 kg)
>20 Kg 1500 ml + (20 ml/kg per day for each kg over 20 kg) Wt
mL/h
Surgical trauma
Type of Surgery
Fluid replacement
Minimal
Inguinal hernia repair
1-2 mlkg-1hr-1
Moderate
Ureteral implantation
4 mlkg-1hr-1
Severe
Scoliosis, bowel obstruction
> 6 mlkg-1hr-1

44. Replacement of blood loss
In children, all blood loss should be replaced.
Done with packed RBCs/whole blood/Crystalloid/ Colloids
Davenport’s law :
<10% blood loss : No blood req.
10-20%  Consider case by case
>20% Consider packed RBCs/Whole blood
Replacement : Crystalloid 3 ml for each ml of
blood loss
Ensure adequate oxygenation
Minimum hematocrit 30% older children
40% neonates acceptable
Sacrococcygeal Teratoma

45. Intraoperative Fluid Management
Responsibility of an anesthesiologist
Sufficient fluid required to compensate for NBM hrs + insensible loss during op.
Loss considerable during major abdominal / thoracic surgery
In most cases 10 ml/kg/hr of Ringer lactate in D5 in water
Blood loss : Weighing sponges
Suction bottle accumulation
Actual loss more because of blood in drapes and op. field

46. Intraoperative Fluid Management ……..
In a child with normal Hb pre-op. : Whole blood / packed RBCs infusion if blood loss 10% of B.V.
FFP/Albumin in extreme dissection without blood loss.
Emergency : Trauma / G.I. Bleed  Continue Pre-op. resuscitation with rapid transfusion during op.
Prolonged hours of op.
 Monitoring Urine Output
 Serum Electrolyte & blood glucose
 Hematocrit and blood gases.

47. Post Op-Period
- Optimum replacement and maintenance pre. and intraop.  child in fluid and electrolyte balance postop.
Immediate Post-Op.
Drainage from chest tube/ intraperitoneal drains measured & replaced with blood plasma
GIT drainage collected  Sample for electrolytes  Measured vol. replaced at intervals of 4-12 hours.
Satisfactory oral intake : 3-5 days in most cases.

48. Review of Finer Points
Why fluid therapy needs special consideration in children?
1) Greater insensible loss
2) Greater urinary loss
3) Larger turn over
4) Inadequate expression of thirst
5) Easy fluid overload
6) Small total volume required
7) Diffusion volume and distribution of body water

49. Disturbance in Fluid Balance in adults
Extracellular vol. deficit : Common fluid disorder in surgical patients.
Acute deficit associated with CVS & CNS signs.
Chronic deficit :  in skin turgor and sunken eyes + CVS & CNS signs.

50. Signs and Symptoms of Volume Disturbances
System
Volume Deficit
Volume Excess
Generalized
Weight loss
Decreased skin turgor
Weight gain
Peripheral edema
Cardiac
Tachycardia
Orthostasis/
hypotension
Increased cardiac output
Increased central venous pressure
Collapsed neck veins
Distended neck veins Murmur
Renal
Oliguria, Azotemia
Gastrointestinal
Ileus
Bowel edema
Pulmonary
Pulmonary edema

51. Laboratory Exam :
Severe deficit   BUN
 Hemoconcentration
  G.F.R.
 Urine osmolality > Serum osmolality
 Urine Na < 20 mEq/L.
Na+ concentration does not reflect vol. deficit.

52. What are the common causes of vol. def. in surgical patients?
Loss of GIT fluid : NG suction Peritonitis
Vomiting Obstruction
Diarrhoea
Fistula
Sequestration sec. to soft tissue injury
Burn
Prolonged surgery : Intra-abdominal procedure
Intestinal Obstruction

53. Volume changes sensed by
Volume Control
Volume changes sensed by
Baroreceptor
Osmoreceptors
Modulate Vol.
Sensors located in Aortic arch and carotid sinsuses
Detect changes in fluid osmolality through osmoreceptors changes in thirst & diuresis through kidney

54. Electrolyte Abnormalities
Sodium
Normal values 135 – 145 mEq / L
Concentration Changes : Changes in Serum Na+ inversely proportional to TBW
Hyponatremia 
(Excess of ECW)
Volume Status (ECV)
High
Normal
Low
 Intake
Hyperglycemia
 Sodium intake
Postop ADH secretion
 Plasma lipids/ proteins
Gastrointestinal losses
Drugs
SIADH
Renal losses
Water intoxication
Diuretics
Primary renal disease

55. Low Serum Sodium level - Na+ depletion
- Dilution Intentional
Iatrogenic
To differentiate the Etiology : Systemic review of the causes
Exclude hyperosmolar causes (Hyperglycemia / Mannitol)
Consider depletional / dilutional causes
Extrarenal (GIT) loss : Urine Na (<20 mEq/L)
Renal loss : Urine Na (>20 mEq/L)

56. How will you treat Hyponatremia?
Most cases treated by free water restriction
If severe : Restrict Na+
Symptomatic Hyponatremia (< 120 mEq/L)
If neurological s/s present : Give 3% NS
 Na+ level no more than 1 mEq/L/hour until Se. level 130 mEq/L or s/s improve.
Asym. Hyponatremia :  Na+ level by no more than 0.5 mEq/L to a max. of 12 mEq/L/day. slower in chr. states
Rapid correction may cause PONTINE MYELINOLYSIS with seizures, weakness / paresis, akiness and unresponsiveness  permanent brain damage & death.

57. Hypernatremia (Loss of free water / gain of sodium)
Volume status
High
Normal
Low
Iatrogenic Na+ adm.
Nonrenal water loss
Mineralocorticoid excess
Aldosteronism
Cushing’s disease
Congenital adrenal hyperplasia
Skin
Gastrointestinal
Renal water loss
Renal disease
Diuretics
Osmotic diuretics
Diabetes insipidus
Adrenal failure

58. Hypernatremia - Loss of free water
>145 mEq/L Gain of Na+ in excess of water
How will you treat Hypernatremia?
Hypernatremia : Treat associated water deficit
Hypovolemia : Treat with normal saline, followed by Hypotonic fluid (D5 or D5 in ¼ NS) after restoration of adequate volume status.
Water deficit (L) =
Serum Na – 140 X
TBW
140
 in Se. Na+ no more than 1 mEq/h and 12 mEq/d.
Chr. hypernatremia : Sodium correction (0.7 mEq/L/H)
Overly rapid correction : Cerebral edema & herniation
Freq. neurological and Se. Na+ assessment required.

59. Potassium Abnormalities
Av. Dietary intake : mEq/d
Flux of K+ influenced by – Surgical stress
Injury
Acidosis
Tissue Collection
Extracellular K+ maintained by renal excretion ( mEq/d)
2% of total K+ : extracellular : Critical to cardiac and neuromuscular function.

60. Hyperkalemia
Serum K+ level above 5.0 mEq/L. (N) range : 3.5 – 5.0 mEq/L.
Hyperkalemia
Increased intake
Potassium supplementation
Blood transfusions
Endogenous load/destruction : hemolysis, rhabomyolysis, crush injury, gastrointestinal hemorrhage
Increased release of K+ from cells.
Acidosis
Rapid rise of extracellular osmolality (hyperglycemia or mannitol)
Impaired excretion by kidney
Potassium-sparing diuretics, ACE inhibitors, NSAIDS
Renal insufficiency / failure

61. What are the signs & symptoms of hyperkalemia?
GIT  Nausea, Vomiting, Diarrhea
Neuro-muscular  Weakness
Ascending paralysis
Resp. failure
CVS : Cardiac arrhythmia
ECG : Peaked T wave (Early)
Flattened P wave
Prolonged PR interval
Widened QRS
Sine wave formation VF

62. How will you treat hyperkalemia?
Potassium removal
Kayexalate (cation exchange resin)
Oral administration is g in mL of 20% sorbitol
Rectal administration is 50 g in 200 mL 20% sorbitol
Shift potassium
Glucose 1 ampule of D50 and regular insulin 5-10 units I.V.
Bicarbonate 1 ampule I.V.
Nebulized Albuterol (10-20 mg)

63. How would you treat hyperkalemia? .......
Goal : To decrease body K+ and shift K+ from extracellular to intracellular.
Discontinue exogenous K+ intake (IV, enteral and parenteral solution)
Circulatory overload / Hypernatremia may result from Kayexalate and bicarbonate.
Ca. Gluconate (5-10 ml of 10%) / Ca Chloride  to counteract myocardial eff. of Hyperkalemia.
May cause digitalis toxicity in patients on digitalis.
Dialysis  When conservative measures fail.

64. Hypokalemia Common in surgical patients
K+  by 0.3 mEq/L for every 0.1  in pH above normal.
Mg depletion due to drugs like amphotercin, Aminoglycosides, Toscarnet, Cisplatin  Renal K+ wastage.

65. Hypokalemia Inadequate intake
Dietary, potassium-free intravenous fluids, potassium-deficient total parenteral nutrition
Excessive potassium excretion
Hyperaldosteronism
Medications  Penicillins, diuretics
Gastrointestinal losses
Direct loss of potassium from gastrointestinal fluid (diarrhea)
Renal loss of potassium (gastric fluid, either as vomiting or high nasogastric output)

66. What are signs & symptoms of hypokalemia?
GIT - ileus, Constipation.
Neuromuscular : Weakness, fatigue,  tendon reflexes paralysis
Cardiovascular : Cardiac arrest
Pulseless electric activity
asystole
ECG Changes : U Waves
T wave frequency
ST seg. changes
Arrhythmia (Patient on digitalis)

67. How will you treat hypokalemia?
Serum potassium level <4.0 mEq/L
Asymptomatic, tolerating enteral nutrition: KCl 40 mEq per enteral access x 1 dose
Asymptomatic, not tolerating enteral nutrition: KCl 20 mEq IV q2h x 2 doses
Symptomatic: KCl 20 mEq IV q1h x 4 doses
Recheck K+ level 2 hrs after end of infusion; if <3.5 mEq/L & asymptomatic; replace as per above protocol

68. Potassium repletion : Determined by symptoms
Oral Supplementation : Mild / asymptomatic.
IV : Not more than mEq/h in unmonitored setting.
40 mEq/hr if ECG monitoring available.
If sec. to Mg depletion : Correct Mg def. first
Exercise caution in patient without oliguria / impaired renal function.

69. Magnesium 4th most common mineral in body Primarily intracellular
1/3 of extracellular Mg bound to serum albumin
Plasma levels poor indicator in presence of Hypoalbuminemia
Normal dietary intake - 20 mEq (240 mg) / day
Excretion : Feces & Urine.

70. Hypermagnesemia : Rare
Impaired renal function
Excess intake
Mg containing laxative / Antacids
What are the signs & symptoms of Hypermagnesemia?
GIT : Nausea & Vomiting
Neuromuscular : Weakness, lethargy, decreased reflexes.
CVS : Hypotension & arrest.
ECG : Increased PR interval
Widened QRS
Elevated T waves.

71. Treatment How will you treat Hypermagnesemia?
Withhold exogenous sources of Mg
Correct volume deficit
Correct acidosis
Acute symptoms : Inj. Ca chloride ml
Dialysis in severe cases.

72. Hypomagnesaemia Diminished absorption or intake
Causes
Diminished absorption or intake
Malabsorption, chronic diarrhea, laxative abuse
Prolonged gastrointestinal suction
Small bowel bypass
Malnutrition
Alcoholism
Increased renal loss
Diuretic therapy (loop diuretics, thiazide diuretics)
Hyperraldosteronism, Bartter’s syndrome
Hyperparathyroidism, hyperthyroidism
Hypercalcemia
Drugs (aminoglycoside, cisplatin, amphotericin B Pentamidine)
Others
Diabetes mellitus
Post parathyroidectomy (hungry bone syndrome)
Respiratory alkalosis
Pregnancy

73. Treatment : Hypomagnesemia
How will you treat Hypomagnesemia?
Asymptomatic / Mild : Oral supplementation
Intravenous correction depends upon severity
Magnesium level mEq/L :
Magnesium sulfate 0.5 mEq/kg in normal saline 250 mL infused IV over 24 h x 3 days
Recheck magnesium level in 3 days

74. Magnesium level < 1.0 mEq/L:
Magnesium sulfate 1 mEq/kg in normal saline 250 mL infused IV over 24 h x 1 day, then 0.5 mEq/kg in normal saline 250 mL infused IV over 24 h x 2 days
Recheck magnesium level in 3 days
If patient has gastric access and needs a bowel regimen:
Milk of magnesia 15 mL (approximately 49 mEq magnesium) q24h per gastric tube; hold for diarrhea

75. Calcium Vast majority in bony matrix Extracellular fluid <1%
Se. Ca2+ : 3 forms  Protein bound 40%
Complexed to anions (PO4) : 10%
Ionized : 50%
Ionized fraction responsible for neuromuscular stability
Albumin measurement necessary when measuring total Ca2+
Adjust total Serum Ca2+ down by 0.8 mg/dL
for every 1-g/dl  in albumin.
Acidosis  Protein binding :  ionized fraction

76. Hypercalcemia Defined as Serum Ca > 8.5 – 10.5 mEq. or
 in ionized as Ca level > mg/dl

77. Causes of hypercalcemia
Increased intake or absorption
Milk-alkali syndrome
Vitamin D or vitamin A excess
Endrocrine disorders
Primary hyperparathyroidism (adenoma, hyperplasia, carcinoma)
Secondary hyperparathyroidism (renal insufficiency, malabsorption)
Acromegaly
Adrenal insufficiency
Neoplastic diseases
Miscellaneous causes
Thiazide diuretic-induced
Paget’s disease of bone
Hypophosphatasia
Immobilization
Familial hypocalciuric hypercalcemia
Complications of renal transplantation
Iatrogenic

78. What are the signs and symptoms of hypercalcemia?
GIT : Anorexia, Nausea/vomiting, abd. pain
Neuromuscular : Weakness, Confusion, Coma, Bonepain
Renal : Polydipsia
CVS : Hypertension, arrhythmia, Polyuria
ECG : Short QT interval
Prolonged PR & QRS interval
 QRS Voltage
T Wave flattening & widening
AV Block  CHB  Cardiac arrest

79. How will you treat Hypercalcemia?
Symptomatic hypercalcemia (>12g/dl) requires t/t
Treatment of hypercalcemia without malignancy
Start with saline volume expansion  This  renal resorption of Ca.
Add loop diuretic after achieving adequate volume status. But these are temporary measures.

80. Drugs :
Biphosphonates
Calcitonin
Corticosteroids
Gallium Nitrate, Mithramycin
Refractory Hypercalcemia : Dialysis

81. Hypocalcemia
Serum Ca2+ <8.5 – 10.5 mEq/L,  in ionized Ca2+ < mg/dL
Decreased intake or absorption
Malabsorption
Small bowel bypass, short bowel
Vitamin D deficit
Increased loss
Alcoholism
Chronic renal insufficiency
Diuretic therapy
Endocrine disease
Hypoparathyroidism (genetic, acquired; including hypo- and hypermagnesemia)
Sepsis
Pseudohypoparathyroidsim
Calcitonin secretion with medullary carcinoma of the thyroid
Familial hypocalcemia

82. What are the signs and symptoms of hypocalcemia?
Neuromuscular : Hyperactive reflexes, Parasthesia
Carpopedal spasm, seizures
Chvostek sign
Trosseau sign
CVS : Heart failure,  cardiac contractility
ECG : Prolonged QT interval
T wave inversion
Heart block
V.F.

83. Hypocalcemia How will you treat hypocalcemia?
Normalized calcium <4.0 mg/dL
With gastric access and tolerating enteral nutrition : Calcium carbonate suspension 1250 mg/5 mL q6h per gastric access; recheck ionized calcium level in 3 days
Without gastric access or not tolerating enteral nutrition: Calcium gluconate 2 g IV over 1 h x 1 dose; recheck ionized calcium level in 3 days.
Acute Hypocalcemia : Inj. Cal. gluconate 10% iv
Correct asso. deficit in Mg, K+, pH
Hypocalcemia refractory if Hypermagnesemia is not treated first

84. Phosphorus Primary intra-cellular divalent anion
Abundant in metabolically active cells
Responsible for maintaining energy production (ATP)
Levels controlled by renal excretion

85. Hyperphosphatemia Causes
Massive load of phosphate into the extracellular fluid
From outside the body
Hypervitaminosis D
Laxatives or enemas containing phosphate
Intravenous phosphate (especially if renal insufficiency coexists)
Cell destruction by chemotherapy of malig, particularly lymphoproliferative disease
Metabolic acidosis (lactic acidosis, ketoacidosis)
Respiratory acidosis (phosphate incorporation into cells is disturbed)
Decreased excretion into urine
Renal failure (acute, chronic)
Hypoparathyroidism
Pseudohypoparathyroidism
Excessive growth hormone (acromegaly)
Pseudoperphosphatemia
Multiple myeloma, hypertriglyceridemia, cell lysis

86. What are the signs and symptoms of Hyperphosphatemia?
Mostly asymptomatic
In advanced casesmetastatic soft tissue deposits
How will you treat Hyperphosphatemia?
Phosphate binders: Sucralfate
Aluminum containing antacid
Dialysis for patient with renal failure

87. Hypophosphatemia Causes Diminished supply or absorption Starvation
Parenteral alimentation with inadequate phosphate content
Malabsorption syndrome, small bowel bypass
Vitamin D-deficient and vitamin D-resistant osteomalacia
Increased loss
Phosphaturic drugs : theophylline, diuretics, bronchodilators, corticosteroids
Hyperparathyroidsim (primary or secondary)
Hyperthyroidism
Renal tubular defects
Inadequately controlled diabetes mellitus
Intracellular shift of phosphorus
Respiratory alkalosis, Salicylate poisoning
Electrolyte abnormalities
Hypercalcemia, Hypomagnesemia
Metabolic alkalosis

88. What are the signs and symptoms of Hypophophatemia?
Usually not significant unless severe deficiency
Related to  O2 del. to tissue and  in ATP
Manifest as cardiac dysfunction / Muscle weakness

89. How will you treat Hypophosphatemia?
Phosphate level 1.0 – 2.5 mg/dL
KPHO4 or NaPO mmol/kg IV over 6 h x 1 dose
Recheck phosphate level in 3 days
Phosphate level < 1.0 mg/dL
Tolerating enternal nutrition : KPHO4 or NaPO mmol/kg over x 1 dose
Recheck phosphate level 4 hours after end of infusion
KPHO4 or NaPO mmol/kg (LBW) over 6 h x 1 dose; recheck phosphate level 4 hours after end of infusion; if <2.5 mg/dL, then KPHO4 or NaPO mmol/kg (LBW) IV over 6 h x 1 dose

90. How to calculate the rate of fluid infusion?
For routine IV set :
15 drops = 1 ml
‘Rule of TEN’ for fluid Cal. for 24 hours
IV fluid in litre / 24 hours x 10 = Drop rate / min
‘Rule of Four’ for fluid Cal for one hour
Drop rate / min. x 4 = Vol. in ml/ hour
For micro-drip IV set
1 ml = 60 drops
No. of drops / min = Vol. in ml / hr.

91. Preoperative Fluid Therapy
A frequently used formula for maintenance fluid
for first 10 Kg : 100 ml / kg / d
for next Kg : Additional 50 ml/kg/d
for wt. > 20 kg : 20 ml / kg / day
But many surgical patients have vol. / electrolyte disturbance associated with their disease.
Therefore, pre-op. volume status and electrolyte assess a must.
Vol. deficits in patients with  Emesis / Diarrhea
Poor intake
III space loss
GI dysfunction
Peritoneal / bowel inflammation
Ascitis, crush injuries

92. Tachycardia & Orthostasis predominate with acute vol
Tachycardia & Orthostasis predominate with acute vol. loss accompanied with oliguria & hemoconcentration
Ac. volume deficits should be corrected prior to surgery.
Start fluid replacement with isotonic crystalloid depending upon electrolyte profile.

93. Patient with CV signs of volume deficit 
1-2 L of isotonic fluid followed by continuous infusion
Resuscitation guide : - Reversal of signs of volume deficit (Vital signs)
- Adequate urine output (½ – 1 ml / kg / hour in adult)
- Correction of base deficit
Close monitoring essential in all esp. so in patients with impaired renal function
Electrolyte abnormality – correct to the extent that ac. S/S relieved prior to surgery.

94. Intraoperative Fluid Therapy
Compensatory mechanism lost with induction of anaesthesia.
Hypotension will manifest if volume deficit present.
Measure blood loss, III space loss, loss from exposed bowel, large soft tissue wounds, complex fractures and burns and replace accordingly.

95. In general which fluid is appropriate intraoperatively?
Selection of fluid needs to be individualized depending upon age, vitals, basic etio. and type of surgery and asso. Illness.
RL: To replace I.O. fluid loss
Most physiological fluid, also corrects acidosis
NS: Used intraop when RL contraind. or when large vol. of resuscitation required like hypovol. shock
D5: Initial fluid replacement
- Replacement for insensible fluid loss
- Maintenance fluid deficit during starvation
- Corrects intracellular dehy. & provides calories

96. Postoperative Fluid Therapy
Should be based on patient’s current estimated volume status and projected ongoing losses.
Any pre. / intraop. deficit should be corrected and ongoing req. included in maintenance.
III sp. losses should be included.
In early post op. period : Isotonic solution
Guide : Vital Signs and Urine output
If uncertainty : CVP / Swan-Ganz Catheter

97. After 24-28 hours : Change to 0
After hours : Change to 0.45% Saline without added dextrose in patient unable to tolerate enteral nutrition.
Add potassium if renal function and urine output adequate.
Daily fluid requirement based on volume electrolyte status.
No need for electrolyte measurement in uncomplicated cases

98. What are special considerations in postoperative fluid therapy?
Overestimation of losses may lead to volume excess
Earliest sign : Weight gain
Av. Post op. patient not requiring nut. support loses ¼ to ½ pound /day.

99. What problems can occur if following iv fluids are used as sole agents for maintenance?
1) D5: Provides only water & glucose. No electrolytes.
Risk of Hyponatremia / Hypokalemia
2) DNS : Contains Na 154 mEq/L,
No Potassium, [(N) child requires mEq]
Risk of hypernatremia, hypokalemia
3) RL : Na 130 mEq, Pot. 4 mEq, No glucose
Risk of Hypernatrania, Hypokalemia, Hypoglycaemia

100. Can we use D5 in initial phase of shock? No, because
1 litre D5   in intravascular
volume by 83 ml
Contains no electrolytes  electrolytes disturbance
Rapid infusion  Osm. diuresis Detrimental
Omphalocele

101. Management in Neuro-surgical patients
Special challenge to anesthesiologists
Often receive diuretics (Mannitol/ Frusemide) to treat cerebral edema
 large amounts of IV fluids to correct pre-op dehydration and to maintain intra/post op. hemodynamic stability
Fluid restriction if excessive  Hypotension   ICP   CPP  devastating

102. Little human data on the impact of fluid on brain
IV fluid therapy manipulates 
1. Osmolality
2. Colloid oncotic pressure
3. Hematocrit  30-33% optimal viscosity & O2 carrying capacity  may improve neurological outcome.
Hct <30%   neurological injury

103. How will you control ICP and brain swelling?
Diuretics : Mannitol & Frusemide used extensively
Mannitol : Creates an osmotic gradient between intravas. comp and brain parenchyma
Frusemide : Reduces cell swelling
Also  CSF production
Hypertonic salt solutions : primarily used for small vol. resuscitation in patient with hemo. Shock
Data suggest that they  ICP and improve CPP similar to Mannitol.
Disadvantages : Danger of Hypernatremia
Rebound  ICP

104. 3. Hypertonic / Hyperoncotic solution –
(E.g. Hypertonic Hetastarch or Dextrose solution)
Have powerful hemodynamic properties
Advantageous in patients with head injury and multiple trauma for prevention of secondary ischemic brain damage
Small volume can restore normovolemia rapidly
Successfully used to treat  ICT in patients with head injury and stroke

105. Implications for Patient Care
Fluid Restriction : Moderate fluid restriction causes  in serum osmolality and prevents hypo-osmotically driven edema  beneficial
Intra Op. Replacement :
Rate should be sufficient to replace urinary output and insensible losses
Repeat osmolality check required
Small volume of RL safe
If large vol. required : use a more isotonic fluid or a combination of isotonic crystalloid and colloid

106. Post op. Period - Large volume not required
Periodic osmolality check and give fluids accordingly
What are the points to be remembered for a head injury patient?
Prompt restoration of systemic pressure is essential
Avoid Hypotonic solution (RL),
Avoid glucose containing solution
Give fluids with osmolality around 300 mOsm/L
Colloids for large volume deficit

107. Subarachanoid Hemorrhage (SAH)
Avoid Hypovolemia and Hyponatremia
Isotonic crystalloids usually take care of hyponatremia
If severe hyponatremia : use mild hypertonic fluids (1.25% or 1.5% saline)
Avoid fluid restriction
Hypertensive / Hypervolemic therapy widely accepted to prevent cerebral vasospasm

108. Management of patients with renal diseases
What are the General Rules?
Fluid restriction : required in edematous and oliguric patients to avoid volume overload, pulmonary congestion, hypertension / hyponatremia
Anuric patient : Fluid restricted upto 500 ml/day only
Oliguric patient : Fluid intake = Urine Output ml
Monitor urine output chart and daily weight.
Loss of weight   in accumulated fluid   edema

109. Do not chase urine output in edematous patient
Urine output  in response to diuretic therapy
Aim is removal of accumulated fluid, therefore continue fluid restriction.
3. Salt restriction : req. to  edema, pulmonary congestion and hypertension.
4. Avoid Hyperkalemia : Can be fatal
Avoid K+ rich food
Avoid K+ rich IV fluids

110. Acute renal failure :  Characterized by rapid decline in renal function.
Accumulation of water, crystalloid solutes and nitrogenous end products.
Has varied presentation :
Pre-renal azotemia
Non-oliguric ac. renal failure
Oliguric renal failure
Diuretic phase of ac. renal failure

111. Pre-renal Azotemia :
Pt. improve with early & adequate fluid therapy
0.5 – 1 Lt. isotonic saline infused over min. if no response  IV diuretics to promote urine flow
Monitor : Pulse, BP and JVP
Give isotonic saline in hypotensive states.
With-hold K+ till urine output is established.

112. Non-oliguric ARF :
Due to Septicemia, drug toxicity, A.I.N.
Diagnosis difficult as there is no  urine output.
High index of suspicion req.
Do not need fluid or salt restriction
Restrict Potassium intake.
Oliguric ARF: If urine output <40 ml/d in adults or <0.5 ml/kg/hr in children
 excretion of water, electrolytes, nitrogenous waste products
Restrict Salt and water (esp. K+)
Maintain daily wt loss chart. (Daily loss of 0.2 to 0.3 kg ideal)
- Treat with diuretics to establish urine outflow.
- If ineffective - Mannitol/ low dose dopamine (<3 µg/kg/min)

113. Diuretic phase of ARF :
Renal functions recover through repair of renal tissue.
- Do not chase urine output at this stage
- Avoid volume depletion and dehydration
- Replace deficit of NaCl, HCO3, K+, Mg etc.
- Preferred IV fluid 0.45% saline with K+ as required

114. Chronic Renal Failure CRF due to chr. glom. disease :
S/S of volume overload and hypertension
 restrict fluid and salt intake
Diuretics
Avoid Hyperkalemia
Preferred IV fluid D-5 or D-10
CRF due to chronic tubulo-interstitial disease :
- Absence of edema / Volume dep. due to polyuria
Advise plenty of fluid and salt intake to prevent dehydration
Correct Met. acidosis  Give Sodium Bicarbonate
Avoid & treat hyperkalemia

115. How will you manage TURP syndrome?
S/S secondary to neuro., CVS and electrolyte imbalance due to absorption of irrigation fluid through prostatic veins.
Risk factors - Surgery > 60 min
- Prostate (Resected wt >30 gms)
- Irrigant volume > 30 L
- Inexperience

116. Prevention : Early diag. and prompt treatment
Correct pre-existing Hyponatremia (risk factor)
Irrigation fluid flow < 300 ml / min
Avoid 5% Dextrose pre-op.
 pre-op. maintenance fluid.
Prophylactic use of Frusemide
Treatment :
Terminate surgery
Diuretics : 66% cases corrected
Fluid restriction
Mannitol 15%
Hypertonic saline : Slow I.V. 3% hypertonic saline.
In general 200 ml sufficient

117. Patient with Trauma
Tissue injury  activated sys. infl. response  permeability of vas. endo  Tissue edema
Plasma shifts to interstitial extra-cellular sp.   intravascular volume
Concurrent hemorrhagic insult  further reduction in plasma volume

118. How will you resuscitate patients with trauma?
Fluid Resuscitation
Improves outcome :  morbidity
Restores physiological homeostasis
Balanced salt solution infusion : current standard
Give as rapid as possible 1-2 L in adults
20 ml / kg in children
No reported difference in outcome with crystalloid v/s colloid resuscitation

119. Options :
Isotonic crystalloids : Readily available, least expensive but larger infusion volume required
Oncotic pr   interstitial edema  detrimental to lung
Hypertonic crystalloids :
Restore blood volume by maintaining a contracted interstitial space
Small volume required
Believed to have positive inotropic effect on myocardium &  in renal, mesenteric & coronary blood flow

120. Colloids
- Favored by some
- More rapid and effective correction of intravascular volume deficits
- Natural Colloids Carry the risk of transmission of infection (HCV, HIV etc.)
- Anaphylactoid reaction

121. Combined Crystalloid – Colloid Resuscitation
Currently under investigation
Hypertonic component  draws water out of intra-cellular space replenishes extra-cellular space.
Colloid component  transiently partitions this fluid in plasma space  prolongs beneficial hemodynamic effects
Studies indicate improved survival when hypertonic saline and Dextran40 (HSD) are used together.
HSD infusion : Corrects meta. derangement
improves arterial O2 tension
 mesenteric & renal micro-circulation

122. Conclusion Accurate fluid, electrolyte assessment & therapy essential
Precise calculation of preop. deficits, maintenance & ongoing loss req. a must for proper management of fluid homeostasis
Practical wisdom indicates it is dose rather than the type of fluid that is important
Judicious fluid management & a keen eye on pt’s status go a long way in benefiting the pt.

123. www.anaesthesia.co.in anaesthesia.co.in@gmail.com
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