1. Alterations in Fluid, Electrolyte and Acid-Base Balance
Lecture 9

2. Introduction Fluid is dynamic state.
Body fluid: is body water that has solutes dissolve on it. Some solutes are electrolyte.
Electrolyte such as Na, K, Ca, CL and Mg.

3. Water may serve as: Medium of metabolic reaction with cells.
Transporter for nutrients, waste products, and other substance.
A lubricant.
Shock absorber.
Regulate and maintain body temperature.

4. General Concepts Intake = Output = Fluid Balance Sensible losses
Urination
Defecation
Wound drainage
Insensible losses
Evaporation from skin
Respiratory loss from lungs

5. Fluid Compartments Intracellular Extracellular 40% of body weight
Two types
Interstitial (between)
Intravascular (inside)
Transcellular: includes cerebrospinal fluid, pleural, peritoneal and synovial fluid.

6. Function of ICF & ECF:
ICF: is vital organ to normal cell function, its contain solutes such as oxygen, electrolytes and glucose. It provides a medium in which metabolic process.
ECF: it is the transport system that carries nutrients and waste product from the cell.

7. Composition of Fluids plasma interstitial intracellular CationsNa K Ca
Mg 2 1 7
Anions Cl
HCO SO
HPO
Protein

9. Pediatric Differences
ECF/ICF ratio varies with age.
Neonates and infants have proportionately larger ECF volume
Infants: high daily fluid requirement with little fluid reserve; this makes the infant vulnerable to dehydration.

10. Distribution of Water

11. Fluid Loss; Infants and <2yr.
excretion is via the urine, feces, lungs and skin
have greater daily fluid loss than older child
more dependent upon adequate intake
greater about of skin surface (BSA), therefore greater insensible loss.
respiratory and metabolic rates are higher therefore, dehydrate more rapidly

12. FIGURE 23– The newborn and infant have a high percentage of body weight comprised of water, especially extracellular fluid, which is lost from the body easily. Note the small stomach size which limits ability to rehydrate quickly.
Jane W. Ball and Ruth C. Bindler Child Health Nursing: Partnering with Children & Families
© 2006 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved.

13. Pediatric differences
<2yr kidneys immature
less able to conserve or excrete water and solutes effectively
Infants have weaker transport system (ion, bicarbonate) greater risk for acid/base imbalances
Difficulty regulating electrolyte such as Na, Ca

14. Fluid and Electrolyte Transport
PASSIVE TRANSPORT SYSTEMS
Diffusion
Filtration
Osmosis
ACTIVE TRANSPORT SYSTEM
Pumping
Requires energy expenditure

15. 1. Diffusion
Molecules move across a biological membrane from an area of higher to an area of lower concentration
Membrane types
Permeable
Semi-permeable

16. 2. Filtration
Movement of solute and solvent across a membrane caused by hydrostatic (water pushing) pressure
Occurs at the capillary level
If normal pressure gradient changes (as occurs with right-sided heart failure) edema results from “third spacing”

17. 3. Osmosis
Movement of solvent from an area of lower solute concentration to one of higher concentration
Occurs through a semipermeable membrane using osmotic (water pulling) pressure

18. Sodium is the major determinant of serum osmolality.
Solutes are substance dissolved in liquid.
Solvent: is the component of solution that can dissolve in the solutes.
Crystalloid: salts that dissolved readily in to true solution.
Colloids: substance such as large protein molecules that do not dissolved in true solution.
Sodium is the major determinant of serum osmolality.

19. 4. Active Transport System
Solutes can be moved against a concentration gradient
Also called “pumping”
Dependent on the presence of ATP

20. Regulation of ECF

21. Hormonal regulation

22. Fluid Volume Imbalances
Dehydration: loss of ECF fluid and sodium.
Caused by: vomiting, diarrhea, hemorrhage, burns, NG suction.
Manifested by wt loss, poor skin turgor, dry mucous memb., VS changes, sunken fontanel
Fluid overload: excess ECF fluid and excess interstitial fluid volume with edema.
Causes: fluid overload, CHF.
Manifested by wt.gain, puffy face and extremities, enlarged liver.

23. Nursing Considerations
How can the nurse determine if the child is mildly dehydrated vs moderately dehydrated?

24. Mild Dehydration: by history.
hard to detect because the child may be alert, have moist mucous membranes and normal skin turgor.
Wt loss may be up to 5% of body weight.
The infant might be irritable; the older child might be thirsty
vital signs will probably be normal
Capillary refill will most likely be normal
Urine output may be normal or sl less

25. Moderate Dehydration
dry mucous membranes; delayed cap refill >2 sec; Wt loss 6-9% of body weight
irritable, lethargic, unable to play, restless
decreased urinary output: <1ml/kg/hr; dark urine with SG > (in child >2yr)
Sunken fontanel
HR increased, BP decreased. Postural vital signs

26. Severe Dehydration wt loss > 10% body weight lethargic/comatose
rapid weak pulse with BP low or undetectable; RR variable and labored.
dry mucous membranes/parched; sunken fontanel
decr or absent urinary output.
Cap refill >4sec

27. Types of Dehydration and Sodium Loss
Sodium may be:
Low
High
Or normal

28. 1. Isotonic Dehydration or Isonatremic Dehydration
Loss of sodium and water are in proportion
Most of fluid lost is from extracellular component
Serum sodium is normal ( mEq/L).
Most practitioners consider below 135 and above 148 a more conservative parameter ( )
Most common form of dehydration in young children from vomiting and diarrhea.

29. 2. Hypotonic or Hyponatremic Dehydration
Greater loss of sodium than water
Serum sodium below normal
Compensatory shift of fluids from extracellular to intracellular makes extracellular dehydration worse.
Caused by severe and prolonged vomiting and diarrhea, burns, renal disease. Also by treatment of dehydration with IV fluids without electrolytes.

30. 3. Hypertonic or Hypernatremic Dehydration
Greater loss of water than sodium
Serum sodium is elevated
Compensatory shift from intracellular to extracellular which masks the severity of water loss (dehydration) delaying signs and symptoms until condition is quite serious.
Caused by concentrated IV fluids or tube feedings.

31. Etiology of dehydration
Vomiting and diarrhea, nasogastric suction and burn.
Water loss = under the warmer.
Accumulation of fluid in third space.
Over use diuretics.
Excessive exercise

32. Rotavirus Common viral form of diarrhea
All ages but 3 mo-2yrs most common
Fecal/oral route
Virus remains active;
10 days on hard, dry surfaces
4 hrs on human hands
1 wk on wet areas

33. Rotavirus (cont.) Incubation period 1-3 days
Symptoms: mild/mod fever, stomach ache, frequent watery stools (20/day)
Treatment: prevention! Hand washing and isolation of the infected child.
Fluid rehydration for diarrhea, advanced to bland diet for older children
Breast milk for the infant who BF

34. Clinical Management for Dehydration
Blood may be drawn to assess electrolytes, BUN and Creatinine levels
an IV may be placed the same time
Oral Rehydration Solution is the treatment of choice for mild-moderate dehydration
1-3 tsp of ORS every 10-15min to start (even if vomits some)
50ml/Kg/Hr is the goal for rehydration.

35. Why are drinks high in glucose avoided during rehydration?
Simple sugars increases the osmotic effect in the intestine by pulling water into the colon, thereby increasing diarrhea and subsequent fluid/electrolyte loss
Drinks high in glucose: apple juice, sodas, jello water.
Simple sugars increases the osmotic effect in the intestine by pulling water into the colon, thereby increasing diarrhea and subsequent fluid/electrolyte loss
Drinks high in glucose: apple juice, sodas, jello water.

36. Recommended foods during rehydration progression:
starches, cooked fruits & vegetables, soups, yogurt, formula, breast milk.
recent research has shown no difference than return to normal diet with some attention to lactose containing foods, depending upon the child’s response.

37. IV Therapy
Used for severe dehydration or in the child who will not/cannot tolerate ORS
24hr maintenance plus replacement given within first 6-8hr (in ER) to rapidly expand the intravascular space. Usually a normal saline bolus.
slower IV rate for the remainder of the first 24hrs
nurse records IV volume infused hourly

38. Which of the following IV solutions replaces Sodium?
D5 W
Lactated Ringers
Normal Saline
D5 ½ NS

39. Calculation of intravenous fluid needs: maintenance
For the 1st 10 Kg, replace at 100ml/Kg
for the second 10 Kg, replace at 50ml/Kg
for >20kg, replace at 20ml/Kg

40. Example of Maintenance Fluid Calculation
Your patient is a 10 yr old weighing 35 Kg. You want to determine this patient’s 24hr maintenance fluid needs:
for the first 10 Kg give 100ml/Kg = 1000ml
for the second 10 Kg: ml/Kg = 500ml
for the remaining 15 Kg (35-20Kg) , replace at 20 ml/Kg = 20 (15) = 300ml
= 1800ml/day.

41. How much fluid should this patient get per hour?
1800 ml / 24 hrs = 75 ml/hr.
Therefore, if the patient were NPO and not taking in fluids from any other source, the IV should be running at 75ml/hr.
If there is a deficit that also needs to be replaced, the IV rate may be slightly higher for a defined period of time.
If the patient is receiving fluids from other sources, these need to be accounted as well

42. Fluid Overload:Edema
Increase capillary blood flow: inflammation, infection
venous congestion: ECF excess, Rt sided heart failure, muscle paralysis.
Increase albumin excess: Nephrotic Syndrome
Decrease albumin synthesis: Kwashiorkor, liver cirrhosis
Increase capillary permeability: inflam/ burns
blocked lymphatic drainage: tumors/surgury.

43. Assessment/Management of Edema
ascites; periorbital edema
pitting edema for degree of swelling
daily wt and strickt I and O
elevation/change position Q2hr/ protect skin against breakdown
distraction to deal with discomfort and limitations of edema.

44. Electrolyte Imbalances
Electrolytes usually gained and lost in relatively equal amounts to maintain balance
Imbalance caused by:
Abnormal route of loss (vomiting/diarrhea) can disturb electrolyte balance
Disproportionate IV supplementation
Disease states: renal dis.

45. Hypernatremia Excess serum sodium in relation to water >146 mmol/l
Causes:
Too concentrated infant formula
Not enough water intake
Clinical manif: thirst, lethary, confusion
Seizures occur when rapid or is severe.
Lab test: serum sodium
Treatment: hypotonic IV solution

46. Hyponatremia Excess water in relation to serum sodium < 135 mmol/l
Most common sodium imbalance in children
Causes:
Infants vulnerable to water intoxication: dilute form, poorly developed thirst mech so cont to drink and can’t excrete excess water or IV fluid.

47. Hyponatremia (cont)
Clinical manif: decreased level of consciousness, swelling of brain cells.
Anorexia, headache, muscle weakness, lethargy, confusion or coma.
Seizures occur when rapid or severe.
Lab tests: serum sodium
Treatment: hypertonic solution.

48. Hyperkalemia Excess serum potassium > 5.3 meq/l Causes:
excess K intake from IV overload, blood transfusion, rapid cell death (hemolytic crisis, large tumor destruction from chemo , massive trauma, metabolic acidosis from prolonged diarrhea and in DM when insulin levels are low
Insulin drives K back into the cells
decreased K loss from Renal insufficiency

49. Hyperkalemia (cont)
Clinical manif: all are related to muscle dysfunction: hyperactivitiy of GI smooth muscle: intestinal cramping and diarrhea.
Weak skeletal muscles
Lethargy
Cardiac arrhythmias (tachycardia, prolonged QRS, peaked T waves: also AV block and venticular Tachy).
Lab test: serum potassium
Treatment: correct underlying condition
dialysis (peritoneal or hemo), Kayexalate (po or enema), K wasting diuretics, IV calcium, bicarbonate, insulin and glucose.
Low potassium diet.

50. Hypokalemia Decreased serum potassium < 3.5 meq/l
Causes: diarrhea and vomiting, diuretics, osmotic diuresis (glucose in urine as in DM), NPO without K replacement in IV, NG Suction,
Also in nephrotic syndrome, cirrhosis, Cushing Syndrome, CHF

51. Hypokalemia (cont) Clinical manif: muscle dysfunction
Slowed GI smooth muscle resulting in abdominal distention, constipation and paralytic ileus
Skeletal muscles are weak; may effect respiratory muscles
Cardiac arrhythmias: hypokalemia potentiates Digitoxin Toxicity.
Lab test: serum potassium
Treatment: oral and/or IV potassium, diet rich in K.

52. Hypercalcemia Excess calcium 5meq/l
Needs vit D for efficient absorption; most of Ca is stored in the bones.
Causes: bone tumors that cause bone destruction, chemo theraoy release Ca from the bones; immobilization causes loss from the bones (usually excreted) but if kidneys can’t clear it, hypercalcemia results, increased intake.

53. Hypercalcemia (cont)
Clinical manif: Ca imbalances alter neuromuscular irritability with non-specific symptoms
Constipation, anorexia, N/V, fatigue, skeletal muscle weakness, confusion, lethargy.
Renal calculi, cardiac arrhythmias
HyperCa increases Na and K excretion leading to polyuria and polydipsia.
Rx: serum Ca, Ionized Ca, fluids, Lasix, steroids, dialysis.

54. Hypocalcemia Decreased serum calcium < 4 meq/l
Causes: decreased intake of Ca and/or Vit D
Limited exposure to sunlight, premature infants and dark skinned people at increased risk to inadeq. Vit D and therefore decreased Ca absorption.
Parathyroid dysfunction, multiple transfusion (Citrate binds Calcium), steatorrhea (as in pancreatitis) binds Calcium in the stool.

55. Hypocalcemia (cont)
Clinical Manif:acute situation related to increased muscular excitability: tetany.
In children: cramping, tingling around the mouth or fingers.
In infants: tremors, muscle twitches, brief tonic-clonic seizures, CHF.
Laryngospasm, seizures and cardiac arrhythmias in severe situations.
Chvostek’s Sx: p 755 tap the skin lightly in front of the ear (over the facial nerve), if the corner of the mouth draws up, d/t muscular contraction, + Chvostek’s Sx.
Trousseau’s Sx: + if carpal spasm after BP cuff inflated ~ 3min.

56. Hypocalcemia (cont 2)
In children and adolescents, chronic hypocalcemia more common, manif. By spontaneous fractures. Lab tests: serum Ca; bone density study Rx: oral and/or IV Ca, Ca rich diet

57. Acid Base Balance Normal arterial blood pH: 7.35-7.43 (in general)
Acidosis < 7.35 : too much acid
Alkalosis > 7.45 : too little acid
pCO2 reflects carbonic acid status:
HCO3- reflects metabolic acid status:

58. Respiratory Acidosis caused by decrease respiratory effort
build up of CO2 in the blood
pH decr or normal; pCO2 incr.
Symptoms manifested: confusion, lethargy, increase ICP, coma, tachycardia, arrhythmias

59. Management of Respiratory Acidosis
Incr ventilatory rate
give O2
intubate
adm NaHCO3

60. Respiratory Alkalosis
caused by hyperventilation
CO2 is being blown off
pH incr : pCo2 decr
Symptoms: dizziness, confusion, neuromuscular irritability, paresthesias in extremities and circumoral, muscle cramping.

61. Management of Resp. Alkalosis
First determine if oxygenation is adequate, if not, you don’t want to slow the RR.
Determine the cause and correct it:
Causes of hypervent: hypoxemia, anxiety, pain, fever, ASA toxicity, meningitis/encephalitis, Gram - sepsis, mechanical overventilation.

62. Metabolic Acidosis caused by a loss of bicarbonate (HCO3)
therefore, is an incr of acids in the blood
pH decr or moving towards normal
pCo2 decr ; HCO3 decr
Symptoms: Kussmaul respirations = incr rate and depth as compensation (hyperventilation/acetone breath), confusion, hypotension, tissue hypoxia, cardiac arrhythmias, pulmonary edema.

63. Management of Metabolic Acidosis
Identify and treat underlying cause
In severe case may give IV NaHCO3 to incr pH, or insulin/glucose.
Causes: ingestion of ASA, antifreeze, oliguria, lactic acidosis (tissue hypoxia).
Loss of HCO3: urine disease, diarrhea, Renal failure.

64. Metabolic Alkalosis caused by loss of H+ or HCO3 retention
HCO3 incr with probable incr in pH, incr pCO2.
Symptoms:weak, dizzy, muscle cramps, twitching, tremors, slow shallow resp., disorientation, seizures.

65. Management of Metabolic Alkalosis
correct underlying cause; facilitate renal excretion of HCO3.
admin NS, K+ if hypokalemic, replace loss of fluids, monitor I and O and electrolytes
Causes: prolonged vomiting, antacids, loss of NG fluids, hypokalemia from prolonged diuretic use, multiple blood transfusion with citrate.

66. ABG Basic (Uncompensated) Analysis
Resp Acidosis: low pH and high PaCO2
Resp Alkalosis: incr pH and low PaCO2
Metab Acidosis: low pH and nl PaCo2; decr HCO3
Metab Alkalosis: high pH; nl PaCO2 ; high HCO3

67. Examples of ABG: pH 7.35-7.45 PaCO2 35-45 HCO3 20-28 = Norms
Resp Acidosis
Resp Alkalosis
Metabolic Acidosis
Metabolic Alkalosis