Download Fluids Lecture Notes Part I

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Fluids Lecture Notes Part I
Water
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Most important nutrient of life; humans can only survive for a few days without it
Main need for the body’s life-supporting functions
90-93% of body fluids
Water
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Solvent in which body salts, nutrients, and wastes are dissolved and transported
Protection of the blood volume (intravascular compartment) is the single most important aspect of fluid balance
homeostasis, even at the expense of creating other electrolyte imbalances
Fluid Balance
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Fluid is a state of balance when the following occurs :
– Water and electrolytes are in the proper proportions
– Fluids are distributed normally between compartments
– Lost body water and electrolytes are replaced
– Excess water and electrolytes are eliminated
Even small fluctuations in the amount of water in the body can have harmful or fatal consequences
Functions of Water in the Body
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Water is vital to health and normal cellular function, serving as:
– 1. Transportation
– 2. Excretion
– 3. Regulation
– 4. Lubrication
– 5. Medium
– 6. Insulator
Review of Basics
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Water: 60% body weight in adults (approximately 40 liters)
Intracellular fluid (ICF): 60% of body fluids (approximately 25 liters)
• Extracellular (ECF): 40% of body fluids (approx. 15 liters)
– Plasma (IVF): 25% ECF (3 – 5 liters)
– Interstitial: 75% ECF (11 liters)
– Transcellular (CSF, GI tract, etc.): 1-2 liters
• Electrolytes control fluid shifts between compartments
Body Fluid Distribution
Transcellular (‘Third-Space’) Fluid: Fluid in Transit & Special Spaces
Water Movement in Major Fluid Compartments
Electrolyte Composition of Body Fluids
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3 Factors Affecting Amount of Body Water
• Age—Elderly have less water
• Gender—Females have less water due to increased body fat
• Body fat—Less water, because fat cells contain very little water
Changes in Body Water Content with Age, Sex, Body Weight
•The older a person gets, the less % of body fluid there is
•Females have less water due to increased body fat
•Obese people have lower than normal body water %
Patients at Risk for Fluid Imbalances
• Infants
• Elderly
• Obese
• Females
• Apathetic, confused, very ill (debilitated)
• Unconscious, comatose
• Patients with…
– Fever
– Tracheostomy
– Cerebral injury
– Swallowing difficulties
• Burn patients
• Renal, cardiac patients
Require diligent monitoring by nursing staff!
Infants and Young Children
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Greater need for water
F & E alterations occur more frequently, rapidly
ECF: over half of the total body water at birth
Large body surface
•Increased metabolic rate (need more water)
•Immature kidneys (not as efficient in conserving water)
The Elderly
• High risk for imbalances due to age related changes
• Less total body water
• More chronic disease processes
• Decreased thirst
• Difficulty concentrating or diluting urine
• Difficulty regulating Na+ and K+
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Each Day…
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The body gains and loses water
Gains and losses must be balanced to maintain body fluid balance
Water Balance
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Total body water
Enters body
– Osmosis from digestive tract
• Also produced by cellular metabolism
Exits body
– Urinary, digestive, respiratory, & integumentary systems
Maintaining Fluid Balance
• Intake should equal output and average around 2,600 ml for an adult
• Average adult intake:
– Fluids: 1,500 ml
– Water from ingested foods: 800 ml
– Water formed from cellular metabolism (metabolic water): 300 ml
Maintaining Fluid Balance
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Average adult output:
– Urine: 1,500 ml
• Output at least 30 ml/hour
– Feces: 100 ml
– Insensible loss: 1,000 ml (600 ml losses from skin and 400 ml expired air from lungs)
Sources of Fluid Intake
• Measurable:
– Oral fluids
– Rehydration fluids
– Enteral feedings
– Parenteral fluids
– Enemas
– Irrigation fluids
• Not measurable:
– Solid foods
– Metabolic water (water produced through oxidation)
Oral Rehydration Therapy
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Oral fluid and electrolyte replacement
• Used to treat mild to moderate dehydration in a stable patient
• Contains: water, electrolytes, glucose in therapeutic amounts
• Examples: Pedialyte, Resol
Oral Rehydration Therapy
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Fluids like soda, tea, fruit juices, and water are not appropriate for oral rehydration (don’t contain proper electrolytes;
too much sugar)
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Sodium and glucose should be in a 1:1 ratio in terms of osmolarity
Rehydration solution (homemade recipe): 8 tsp of table sugar, 1/2 tsp of salt, 1/2 tsp of sodium bicarbonate (baking
soda), and 1/3 tsp of potassium chloride to 1 L of water
Enteral Feedings: Use GI System
• Enteral: alimentary, GI tract (much preferred)
• Commercial formulas: water, protein, vitamins, electrolytes, glucose
• NG tube, PEG tube
• Example: Jevity, Pulmocare
• Need supplemental water
Enteral Feedings
• Any or all gastric residuals must be returned to stomach
• Signs of feeding intolerance:
– Vomiting, diarrhea
– Discomfort
– Distention
– Residuals > one half (1/2) of the feeding volume
IV Therapy: Parenteral
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Parenteral: any fluid or medication administered by means other than alimentary tract (i.e., intravenous, intramuscular)
Intravenous therapy: administration of fluids, electrolytes, nutrients, or medications by venous route
Severe, life-threatening dehydration
Clients receiving IV therapy require constant monitoring for complications
Types of IV Solutions
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Hypotonic (< 270 mmol/L)
– Provides more water than electrolytes, diluting ECF
– Movement of water from ECF to cells
– 0.45% saline; D5W (after dextrose metabolized)
•Provides free water for cellular hydration and renal excretion
•Not for clients with - ICP or third-space fluid shifts
Types of IV Solutions
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Isotonic (270-300 mmol/L)
– Expands only ECF
– No net loss or gain from ICF
– Fluid replacement for patients with ECF volume deficit
– NS (0.9% saline), LR
•Expands vascular volume
•Assess for hypervolemia (bounding pulse, SOB)
Types of IV Solutions
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Hypertonic (>300 mmol/L)
– Raises osmolarity of ECF and expands it
– Draws water out of cells into ECF
– D5½NS, D5NS, D5LR, 3% NaCl, TPN, electrolyte additives
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•Irritating to veins
•Not for clients with kidney, heart disease, dehydrated
•Fluid overload, hypervolemia
Plasma Expanders
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Stay in vascular space, increase intravascular osmotic pressure
Advantages: remain in intravascular space for hours
Disadvantages: risk of sensitivity reactions
Colloids, dextran, & hetastarch; blood products
Plasma Expanders
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Colloids: protein solutions such as albumin
Dextran: complex synthetic sugar
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Metabolized slowly; remains in vascular space longer than dextrose
Blood products (whole blood or PRBC)
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Restores hemoglobin in blood loss
Sources of Fluid Output
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Measurable (sensible loss):
– Urine
– Emesis
– Feces
– Drainage from body cavities (NG suction, chest tube drainage)
Sources of Fluid Output
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Not measurable (insensible loss):
– Perspiration
– Skin vaporization
– Lung vaporization
– 15-20 ml/ kg/ day
Nasogastric Suction
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Increased loss of electrolytes
Hypochloremic metabolic alkalosis
Irrigate tube with isotonic saline (0.9% saline)
Regulators of Fluid Balance
• Thirst mechanism
– Primary regulator of fluid intake
• Kidneys
– Primary regulator of fluid output, F & E
• GI tract
– Intake & output
• Insensible loss
– Skin, lungs
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• Hormone regulators
– ADH, aldosterone, ANP
Thirst
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Earliest symptom of water deficit
Increased osmolarity, fluid volume deficit
Occurs when water loss is 2% of body weight
Elderly: decreased thirst sensation
Kidneys
• Major regulatory organ for output, fluid & electrolyte balance
• Urine: waste materials from blood
• Receive 180 liters of blood/ day to filter
• Produce 1200 -1500 ml of urine
GI Tract
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Absorb water from fluid, food
Lose water: feces
Skin
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Regulated by sympathetic nervous system
Activates sweat glands
Insensible: 500 - 600 ml/ day
Lungs
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Insensible
Increases with rate and depth of respirations, oxygen delivery
400 ml/ day
Hormonal Regulators: Compensatory Mechanisms
• Antidiuretic hormone (ADH) from posterior pituitary
• Aldosterone from adrenal cortex (renin-angiotensin-aldosterone system)
• Atrial natriuretic peptide (ANP)
Antidiuretic Hormone (ADH)
• Stored in posterior pituitary gland
• Released in response to increased blood osmolarity (dehydration, hemoconcentration, hypovolemia)
• Makes tubules and collecting ducts more permeable to water
ADH Increased HYPOTONIC IVF Volume
• ADH = WATER
– Pure water returns into systemic circulation
• Increased HYPOTONIC intravascular fluid volume
– Dilutes blood
– Decreased serum osmolarity
• Scant urinary output (concentrated urine)
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Aldosterone
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Aldosterone released by adrenal cortex in response to…
–  Plasma sodium
–  Plasma potassium
Causes the kidney to retain sodium & water and excrete potassium
Renin-Angiotensin-Aldosterone System
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Blood pressure falls
Renin-angiotensin-aldosterone mechanism activated
Renin released from juxtaglomerular complex in kidneys
Renin Angiotensin Aldosterone
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Renin: activates angiotensin
– Causes muscular walls of the small arteries (arterioles) to constrict, increasing blood pressure
– Triggers release of aldosterone from adrenal gland
Aldosterone Increased ISOTONIC IVF Volume
• Aldosterone = SODIUM + WATER
• Aldosterone acts on distal tubules 
•  Reabsorption of sodium & water
– Water follows sodium
•  ISOTONIC intravascular fluid volume
•Serum osmolarity unchanged
•Blood pressure rises
•Increased excretion of potassium
Atrial Natriuretic Peptide (ANP)
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Aldosterone antagonist
– Counterbalance to renin-angiotensin-aldosterone system
Released when atria are stretched by increased blood volume
ANP  Decreased ISOTONIC IVF Volume
• Promotes excretion of both sodium and water
• Reduced: blood volume, blood pressure
• Serum osmolarity unchanged
• Increased: urinary output, salty urine (large amount of urine with high osmolarity)
Urine
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Urine output at least 30 ml/hr
Kidneys: concentrate, dilute urine
– Maintain F & E balance
– Aldosterone, ADH, ANP
Specific gravity: 1.010-1.025
– > 1.025: concentrated, high osmolarity
• Dehydrated
• Conserving fluids
– < 1.010: dilute, low osmolarity
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• Large fluid intake
• Large urine output
Obligatory Urine Output
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Minimum amount of urine needed daily to dissolve and excrete toxic waste products (400 - 600 ml/ 24°)
S.G.  1.032: maximally concentrated, 1200 mmol/L
If 24° output < 400-600 ml:
– Wastes are retained
– Lethal electrolyte build-up (especially  K+)
– Toxic nitrogen build-up
– Metabolic acidosis
Urine Terms
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Anuria: urine output less than 100 ml/ 24°
Oliguria: urine output 100 - 400
ml/ 24°
Polyuria: urine production greater than 2,000 ml/ 24°
Calculate Fluid Replacement
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Method to calculate specific 24 hour fluid needs (do this for your care plans)
30 ml/ kg
Example: 150-pound woman
– 150  2.2 = 68.18
– 68.18 X 30 = 2,045.4
– 24-hour fluid needs (150-lb woman): 2,045.4 mL
Exception: Cardiac or Renal patients
Calculation of Fluid Loss or Gain
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1 L of water = 2.2 lb (1 kg)
500 ml of fluid gain = 1 lb weight gain
500 ml of fluid loss = 1 lb weight loss
Sudden weight gain or loss = gain / loss of body fluid
– Weight gain / loss > 0.5 lb daily (250 ml)
– 2.2 lb (1 kg) gain / loss = 1 L
– 4.4 lb (2 kg) gain / loss = 2 L
Hydration
• Normal state of fluid balance
• Normally hydrated adult:
– Alert
– Moist eyes, mucous membranes
– Urine output = fluid intake
– Urine specific gravity 1.010-1.025
– Skin turgor elastic & mobile
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Assessment of Fluid Balance
• Health History.
• Diagnostic and Laboratory Data.
• Physical Examination
– Most important:
• Daily Weight
• Intake and Output
• Vital signs
– Others:
• Thirst, skin, oral cavity & mucous membranes, eyes, cardiovascular & respiratory systems, neurological status
Health History
• Nutritional history
• Output (urine, bowel, excessive perspiration, drainage)
• Medications
• Body weight changes
• Thirst or excessive drinking
• Exposure to hot environments
• Medical disorders
Diagnostic and Laboratory Data
• Hemoglobin and Hematocrit (H & H)
• Blood Urea Nitrogen (BUN)
• Serum Sodium
• Serum Glucose
• Osmolarity
– Serum Osmolarity: 270 - 300 mmol
– Urine Osmolarity: 500 - 800 mmol
• Urine specific gravity: 1.010 - 1.025
Daily Weights
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Best assessment of hydration status if accurate
Each kilogram of weight lost or gained suggests 1 liter of fluid lost or gained
Same time each day, preferably before breakfast and after first void
Same calibrated scale
Same conditions (clothing, bedding, emptied Foley bag, etc.)
Document
Intake and Output
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Intake
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Output
– Oral fluids
– Parenteral fluids
– Tube feedings
– Catheter irrigants
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Urine output
Liquid feces
Vomitus
NG drainage
Wound drainage
Draining fistulas
Vital Signs
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Signs and symptoms of ECF volume excess and deficit are reflected in changes in:
– BP
– Heart rate
– Respiratory rate
– Temperature
Orthostatic (Postural) Hypotension
• Postural changes in blood pressure or heart rate
• Measurement of BP and HR first in supine, then in sitting, then standing position
• Dehydration:
– SBP  by 15
– DBP  by 10
– HR  by 20
Pulse Quality
• A normal pulse can be felt with moderate pressure of the fingers and can be obliterated with greater pressure
• Easily obliterated
– Fluid volume deficit
• Rapid, weak, thready
– Fluid volume deficit
• Bounding
– Fluid volume excess
Lung Status
• Pulmonary edema
• Crackles—Air passing through fluid in alveoli
• Shortness of breath, crackles, rales, or rhonchi—may signal fluid volume excess due to fluid buildup in the lungs
• Pink, frothy secretions
Skin Turgor
• A decrease in skin turgor is indicated when the skin (on the back of the hand, sternum, or forehead) is pulled up for a
few seconds and does not return to its original state
• Fluid volume deficit
Integument
• Skin should be pink, warm, and dry
• Flushed, dry skin
– Hypernatremia, fluid volume deficit
• Cold, clammy skin
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• Capillary refill > 3 seconds
– Fluid volume deficit
Mucous Membranes
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MM, conjunctiva should be moist
Eyes
– Absence of tearing
– Eyeball soft and sunken
– Fluid volume deficit
•Tongue
–Rough, dry, red
–Dry, fissured tongue
–Absence of salivation
–Fluid volume deficit
•Lips: cracked
Hand Veins
• Hand vein filling is a useful indicator of hydration status
• Normally, hand veins fill and become engorged when the hands are lower than the level of the heart
• Collapsed hand veins in a dependent position indicate deficient fluid status
Edema
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Excessive ECF accumulates in tissue (interstitial) spaces
Nonfunctioning fluid
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Increased hydrostatic pressure
Decreased plasma protein (decreased colloid osmotic pressure)
Increased capillary permeability
Lymphatic obstruction
Edema
• Dependent edema
• Peripheral edema
• Periorbital edema: significant fluid retention
• Cool to touch, taut, shiny
• Good skin care
• Elevate extremities
Edema
• Pitting vs nonpitting
• Generalized vs localized
• Anasarca: severe generalized edema, over entire body
Pitting Edema: Assessment Findings
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1+ edema minimal at pedal sites, 2 mm indentation
2+ marked edema of lower ext., < 5 mm
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3+ edema evident in face, hands, abdomen, sacrum, 5-10 mm
4+ generalized edema, > 10 mm
System for Grading Edema
Anasarca
Third-Spacing
• Abnormal fluid shifts into transcellular space (pericardial, pleural, peritoneal spaces; joint cavities, bowel; abdomen)
• Fluid trapped and stays there
• Physiologically useless
•Causes:
–Tissue damage
–- Hydrostatic pressure
–¯ Colloid osmotic pressure (low albumin)
–Blocked lymph drainage
Ascites
• Abnormal fluid shifts (third-spacing) of intraperitoneal fluid
• Fluid trapped, cannot get back into vascular system
• Measure abdominal girth every shift with a centimeter tape and record (mark on sides)
Fluid Retention
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What is the most reliable way to determine if pt is retaining fluid?
– Daily weights
If a pt gains 1 kg or 2.2 lbs, how much fluid has he retained?
– 1 liter
Can a pt have fluid retention and yet be hypovolemic? Explain
– Yes, fluid not in intravascular space
– Third-spacing
Neck Veins
• Neck veins are normally distended when a client is in the supine position
• These veins flatten when the client moves to a sitting position
• Should be < 4 cm
• Jugular vein distention in a sitting position
– Fluid volume excess
Assessment of Jugular Venous Pressure
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HOB 45º
Vertical distance from sternal angle to highest level of pulsation of internal jugular vein
Normal: 0 – 4 cm
CVP = 4 + this height
External vs Internal Jugular Vein
External Jugular Vein Distention
Central Venous Pressure
• Pressure in the right atrium: central venous pressure (CVP)
• Estimates blood volume
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• Normal: 4-8
• Decreased CVP—hypovolemia
• Increased CVP—hypervolemia
Central Nervous System
• Assessment of client’s level of consciousness and mental status
• Subtle changes in mental status or level of consciousness
• Neuromuscular irritability (DTRs)
• Confusion, weakness, coma
– Severe dehydration
Nursing Diagnoses Relevant to Fluid Imbalances
• Fluid Volume, excess
• Fluid Volume, deficient [Isotonic]
• Fluid Volume, deficient [hyper/hypotonic]
• Fluid Volume, risk for deficient
• Fluid Volume, risk for imbalanced
• Gas Exchange, impaired
• Cardiac Output, decreased
• Deficient Knowledge
• Breathing Pattern, ineffective
• Anxiety
• Thought Processes, disturbed
• Injury, risk for
• Oral Mucous Membrane, impaired
Client Goals
• The client will reestablish normal ECF volume, water, and/or electrolyte balance
• The client will demonstrate knowledge regarding how to promote future ECF volume, water, and electrolyte balance
The client will remain free of complications from fluid or electrolyte imbalance
Fluid Balance & Implementation
• Nursing interventions:
– Monitor daily weights
– Vital signs
– Strict I & O
– Provide oral hygiene
– Initiate oral fluid therapy
– Maintain tube feedings
– Maintain IV access
– Monitor intravenous therapy
– Client teaching
•Collaborative interventions:
–Treat cause of illness
–Assess and reassess patient response to treatment
Client Teaching
• Especially important: older adults
• Reinforce good diet and fluid intake
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Preventative home maintenance: Teach clients how to detect signs of fluid and electrolyte imbalance, such as rapid
weight gain or loss, swelling, changes in normal urine output, muscle weakness, or abnormal skin sensation, and give
them guidelines for when to notify a physician
Client Teaching: Medications
• Diuretics and other medications can increase the risk of fluid and electrolyte imbalance
• Teaching is important to ensure client compliance and to help prevent any problems that can occur with treatment
Fluid Imbalances
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Dehydration (fluid volume deficit)
Overhydration (fluid volume excess)
Fluid Imbalances: Correlate to Serum Sodium Imbalances
Dehydration
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Fluid volume deficit
– Fluid intake is not sufficient to meet body’s fluid needs
– Output is increased over intake
Elderly, infants, children more at risk
Dehydration
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In dehydration, fluid loss occurs first in the extracellular fluid
– Losses occur from both intravascular and interstitial spaces
– Actual vs. Relative
Dehydration: Signs & Symptoms
• Decreased skin turgor
• Dry mucous membranes
• Urine output: < 30 ml/hr in adult
• Postural hypotension
• Weak, rapid, thready pulse
• Increased rate and depth respirations
•Low-grade fever
•Thirst
•Slow filling peripheral veins
Dehydration: Signs & Symptoms
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CVP less than 4 cm H20 in vena cava
BUN elevated out of proportion to serum creatinine
Specific gravity (SG) high (urine)
Flat neck veins in supine position
Marked oliguria, late
Mental status changes
Cold extremities, late
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Degrees of Dehydration
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Mild dehydration
– 2%,  1-2 liters
– Symptoms: thirst
Moderate
– 5%,  3-5 liters
– Symptoms: marked thirst; dry MM; dry skin; poor skin turgor;  temp; tachycardia; tachypnea; SBP 10-15;
oliguria
Degrees of Dehydration
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Severe
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8%,  5-10 liters
Symptoms: flushed skin; SBP 60 or ; behavioral changes
Fatal
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 22-30 liters
Symptoms: anuria; coma; death
Three Types of Dehydration
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Isotonic dehydration
– With equal sodium and fluid loss
– ECF isotonic
– Contraction of the extracellular fluid space only
Three Types of Dehydration
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Hypotonic dehydration
– Greater sodium loss than water
– ECF hypotonic
– Contraction of the extracellular fluid and expansion of the intracellular fluid
Three Types of Dehydration
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Hypertonic dehydration
– Water lost exceeds sodium loss
– ECF hypertonic
– Expansion of the extracellular fluid and contraction of the intracellular fluid
Isotonic Dehydration
•Most common form of dehydration
•Deficit of ECF only
•Also called hypovolemia
(decreased circulating blood volume)
•Water and electrolytes lost in even amounts: serum electrolytes normal
Isotonic Dehydration Cont’d…
•ISO = SAME: there is no gradient, no fluid shifts, no movement of fluid between compartments
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•Involves loss of isotonic fluids from the ECF only (blood and interstitium)
•Renin-angiotensin-aldosterone cycle activated
•S/S of shock occur if severe
•Inadequate tissue perfusion (hypoxia)
Isotonic Dehydration
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Common Causes:
– Hemorrhage
– Decreased fluid intake
– Loss of isotonic fluids (GI, renal, & skin)
• Excessive vomiting
• Gastrointestinal suction
• Diarrhea
• Diuretic therapy
• Excessive urine loss
• Severe wound drainage
• Excessive diaphoresis
Isotonic Dehydration: Assessment
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Weight loss
Hypotension and Orthostatic Hypotension
Rapid, weak pulse
Oliguria: dark, concentrated, scanty urine
Poor skin turgor
Dry skin, MM
 Urine SG
Changes in LOC (irritable to lethargic)
 H & H (except in hemorrhage), serum protein, and BUN
Severe: can lead to SHOCK
Isotonic Dehydration: Interventions
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Monitor daily weight, I&O, skin turgor, LOC and VS
Check skin turgor on forehead or sternum on elderly
Monitor lab values - urine SG, BUN, CBC and Lytes
Replace fluid loss using ISOTONIC fluids
Treat the underlying cause (Imodium, Zofran)
Meticulous oral care
Hypovolemic Shock
• Shock: failure of the heart and blood vessels (circulatory system) to maintain perfusion (enough oxygen-rich blood) to
the vital organs of the body (hypoxia)
• Hypovolemic shock: decreased intravascular fluid volume
• Usually caused by serious bleeding (hemorrhage)
Hypovolemic Shock
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Healthy adult can compensate well up to 15% blood loss (500-750 ml)
Loss of compensation occurs at 30-40% blood loss (1500-2000 ml): at risk for irreversible organ damage,
exsanguination, death
Dehydration due to diarrhea, vomiting, or heavy perspiration can also lead to the development of hypovolemic shock
Assessment of Shock
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Hypotension
Rapid, weak pulse
Cold, moist, clammy skin
Rapid respirations
Decreased urinary output
Thirst
Changes in LOC
Early: apprehension and restlessness
Late: lethargy to coma
Interventions for Shock
• Goal: increase ECF volume and pressure, in order to increase tissue perfusion
• Monitor VS frequently
• Maintain airway, O2
• HOB flat, legs elevated 45 degrees
• Keep warm
• 16 or 18-gauge IV, Type & Cross, CBC
•Start NS, be ready to give blood or plasma expanders
•Continuous pulse oximetry, cardiac monitoring
Hypertonic Dehydration
• Second most common type of dehydration
• Water-loss hypernatremia
• Deficit of ICF and expansion of ECF
• Occurs when water loss from ECF is greater than electrolyte (sodium) loss
• Hyperosmolarity is present (Na+ > 145)
• Fluid pulled from the cells into the blood stream, leading to cellular shrinkage
Hypertonic Dehydration
• Free water deficit or sodium excess
• Hypotonic water loss:
– Excessive perspiration
– Hyperventilation
– Ketoacidosis
– Fever
– Watery diarrhea
– Renal failure
– Diabetes insipidus
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Hypertonic Dehydration
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Hypertonic sodium gain:
– Tube feedings
– Hypertonic fluid replacement
Hypertonic Dehydration
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Debilitation (nursing home client):
– Dysphagia
– Impaired thirst
– Unconsciousness
– Impaired motor function
Diabetes Insipidus (DI)
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A disorder of water metabolism
Deficiency of ADH
Caused by damage/destruction of the pituitary gland/hypothalamus (severe head injury)
Diabetes Insipidus (DI)
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Kidney unable to concentrate urine
– Massive diuresis (4-30 L/ day)
– Constant extreme thirst
– Hypernatremia (Na+ > 145)
– Low urinary osmolality
Hypertonic Dehydration: Assessment
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Thirst
Fair skin Turgor
Warm, doughy skin
Parched mucous membranes
Increased serum sodium (>150 mEq/L)
Increased serum Osmolarity
Increased urine specific gravity (>1.030)
Decreased urine output
Signs of shock are usually not present
Changes in LOC (lethargy, hyperirritability)
Hypertonic Dehydration: Compensatory Mechanisms
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Activation of thirst reflex
 ADH secretion
Hypertonic Dehydration: Interventions
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Correct the free water deficit / sodium excess
Prevent: dilute tube feedings with adequate amounts of water
Monitor I&O, daily weight, skin turgor, LOC, serum sodium and serum Osmolarity
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Administer Hypotonic fluids orally or SLOWLY by IV
Hypertonic Dehydration: Interventions
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Be aware that rapid administration of hypotonic IV fluids can cause swelling of the brain cells, and increased
intracranial pressure
Treat underlying cause (Tylenol, Imodium, Lomotil)
Meticulous oral care
Hypertonic dehydration: Prevention
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Prevent insensible fluid loss
– Hyperventilation, pure water loss with high fevers, and watery diarrhea
Control disease processes
– Diabetic ketoacidosis and diabetes insipidus
Prevent medical treatment causes
– Prolonged NPO, excessive hypertonic fluids, sodium bicarbonate, or tube feedings with inadequate water
Monitor older, debilitated clients
Hypotonic Dehydration
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Relatively uncommon
Loss of more solute (usually sodium) than water
Sodium-loss hyponatremia
Deficit of ECF and expansion of ICF
Na+ and K+ levels decreased
Hypotonic Dehydration
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Osmolarity is decreased (below 270)
Fluids shift from the blood stream into the cells, leading to decreased vascular volume/ shock
Increased cellular swelling—causes increased intracranial pressure and neurological changes - H/A and confusion
Hypotonic Dehydration: Common Causes
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Chronic illness
Chronic renal failure
Malnutrition
Hypotonic fluid replacement
Seen in heat exhaustion / heat stroke
Hypotonic Dehydration: Prevention
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Avoid NPO with ice chips over long periods
Avoid overadministration of hypotonic fluids
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Select the correct IV fluid and rate to meet patient’s rehydration needs
Replace fluid loss during exercise with isotonic fluids
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Hypotonic Dehydration: Prevention
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Watch for low serum osmolarity and serum sodium
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Persons on hypotonic IV fluids
Persons with chronic renal failure
Persons with chronic malnutrition
Hypotonic Dehydration: Assessment
• Hypotension
• Tachycardia
• Very poor skin turgor
• Cold, clammy skin
• Changes in LOC (lethargic to comatose, convulsions)
• Na+ < 120 mEq/L
• K+
Hypotonic Dehydration: Interventions
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Treat the underlying cause
Rehydrate orally with hypertonic fluids
IV administration of NS to restore sodium balance
Potassium replacement
In rare instances hypertonic sodium (3% NS) may be used
Monitor for cardiac dysrhythmias
Meticulous oral care
Administration of IV Fluids: Guidelines
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Give isotonic fluids (NS, LR) for isotonic dehydration
Give hypotonic fluids - (0.45% saline, D5W) SLOWLY to treat hypertonic dehydration
Give NS or hypertonic fluids (D5/0.9% saline, D5/LR) to treat hypotonic dehydration
Monitor: symptoms F & E imbalance
Keep track of I & O
Outcomes
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The client will:
Ingest at least 1500 ml of appropriate fluids
Maintain a fluid output approximately equal to fluid intake