Fluid and Electrolytes

Sensible Loss
Measureable
Wound Drainage: hemovac, JP drain but NOT wound vac because it
pulls the drainage out so it is not accurately depicting true loss.
Stools, Urine: I and O for charting.

Insensible Loss
Cannot be measured in cc/ml unit.
Breathing, Perspiration
Chart: mild, moderate, severe diaphoresis

Gold Standard for Urine Output is 1500ml/hr out of total 2600 (input)
< 30 ml/hr : OR

< 720 ml/hr would be a concern ( 30 x 24 hrs). Charted as UO or diminished UO

< 16 ml/hr: OR

< 400 ml/hr = oliguria ( 16 x 24hrs): given fluids to avoid renal failure

< 2 ml/hr: OR

< 50 ml/hr = anuria (2 x 24 hrs):not functional urine- thick, syrupy, odorous. Dialysis patients.

Fluid Compartments
o

Intracellular Assessments as nurse: #1 Priority (intracellular)

Hypotension
Tachycardia
Weak thread pulse
CO

Extracellular Assessments (Interstitial and Intravascular)

Skin turgor
Dry mucous membranes

Age/Gender Differences with Fluid Compartments

Infants (< 12 months) have more fluid per body surface area. They are primarily made up of more fluid so if they lose some due to N/V/D/Fever
they quickly deteriorate
Elderly have less body fluid per surface area . Why? Gain of adipose tissue and loss of muscle mass. Adipose contains less water. Their thirst
center is less sensitive so they intake less when thirsty. Kidneys dont function as well.
Women > adipose (hormones so less fluid) . Men > muscle mass (more fluid)

Third Space Shifting:

Pitting Edema

Ascites:
Hypovolemia
Respiratory Prob.
GI problems
Cerebral

Causes
CHF
Renal Failure: dialysis not working
PVD: venous return is a problem
PAD:
Liver failure:
Cirrhosis
ETOH-drink nutrition rather than eat protein
Chronic hepatitis
Cerebral edema

Fluid in brain cells

Severe Burns

Fluid going into air, bandages, dressings, etc

Cavity Bleeding

Abdominal aneurysm

Knee Effusion/Knee
bleed

Osteo arthritis- bilateral joint effusion

Rheumatory arthritis- bilateral joint effusion
Injury- unilateral joint effusion
Hemophiliacs- unilateral joint effusion (hitting part
causing bleed)

Treatment

IV albumin
TPN
Paracentesis (draw about 1500-2L q day to avoid BP )

Homeostasis: equal distribution of fluid and solutes in compartments.( F & E )

Osmolarity (outside the body ) concentration of solutes per LITER
Osmolality (inside the body ) concentration of solutes per KG.
Best to use BMP: basic metabolic profile. It will give number of specific solutes. / can determine serum osmolality by putting in
numerical values of specific electrolytes.
Normal Serum level 275-310. Not specific because you dont know which solutes (Na+, K+, etc) are high or low.
Urine Specific Gravity : 15 to 30 with zero in front: 0.015 to 0.030.
Osmosis: fluid moves from an area with MORE fluid to LESS fluid
Fluid moves from an area of LESS concentration to MORE concentration.
Diffusion: PASSIVE: solutes move from areas of HIGH concentration to areas of LOW concentration until equal concentration.
50/50
Diffusion: ACTIVE: solutes move from areas of LOW concentration to areas of HIGH concentration with ATP energy. NOT 50/50
Na+ / K+ pump is an example
80% of K + should be in cell and 20% Na+ out of cell (vascular space) : not normally where Na+/ K+ located.
Na+ is MAJOR EXTRACELLULAR CATION.
K + is MAJOR INTRACELLULAR CATION
Diffusion: FACILITATED: carrier binds to substance and carries it into the cell:
Lack of insulin also stops Na+/K + pump from working.
Insulin is key to open door to allow glucose in.
Insulin also allows K + out of cell.
If patient is hyperglycemic due to lack of insulin, then patient will also be hyperkalemic. TQ

Fluid and Solute Movement inside the vascular space : 2 influences

Hydrostatic Pressure
Like leaf blower
Moves fluid and solute OUT thru capillary walls into
interstitial space
Want hydrostatic pressure to be than COP in arterial blood
so oxygen, nutrients and electrolytes will leave vascular space
and move into cells.
High pressure/low volume
Arterial circulation good nutrients

Colloid Osmotic Pressure: Reabsorption

Like vacuum cleaner
Prevents to much fluid from leaving capillaries despite
hydrostatic pressure
Want hydrostatic pressure to be and COP so biproducts of
metabolism and CO2 will be carried out of cells into venous
blood circulation.
Low pressure/high volume
Venous system has biproducts of lungs, kidneys, liver, GI, skin
Albumin = COP (ascites) the albumin gives water the
pulling power.
Ex. If person has hypOproteinemia= albumin = COP

Semipermeable membrane in kidneys should never allow albumin to filter through. Albumin is necessary for COP.
Proteinuria = poor functioning kidneys= protein filtering out into urine.
If person has low serum total protein levels = protein supplements = outcome = low or absence of peripheral edema.

Kidneys: Role to maintain Fluid balance:

1.

RAAS cascade happens to increase blood supply for kidneys.

Part 1 of RAAS

Part II of RAAS

Aldosterone (hormone) will cause kidneys to reabsorb Na+ / H2O=

o
o
o

Vasoconstriction: redistributes body fluids to needed areas

fluid volume
CO
Renal perfusion
Meds that interfere with the RAAS:

ACE Inhibitors pril : keep body from secreting Aldosterone (lowers blood volume) and stop vasoconstriction.(decreases pressure)
:protects renal tissue for unknown reasons.
2.

Hypothalamus (thirst center) produces AntiDiuretic Hormone: ADH

3.

Pituitary : stores ADH

When kidneys sense that serum osmolality is (fluid levels ) they send signal to pituitary and ask for release of ADH.
ADH tells kidney to re-absorb water which will lower serum osmolality.

COMPLICATIONS WITH FLUID BALANCE/KIDNEY SIGNALS

Complications with ADH:
Head injuries with damage to pituitary
Small Oat Cell lung Cancer/ Cell carcinoma: Think Fluid volume problem/ADH.
Disease
Diabetes Insipidus
Primary: Cannot
produce ADH/born this
way.
Secondary: any of the
above reasons.
SIADH

1.

o
o
o

Manifestations
ADH
Urine Excretion leading to FVD vascular space
FVD = serum electrolytes (concentrated)

Treatments
Secondary problem:
Give ADH until the primary problem can be solved.

o
o
o

ADH
Urine exretion leading to FVE in vascular space
FVE = serum electrolytes (diluted)

Secondary Problem: too much ADH so fluid volume

would need to be fixed until the primary problem can
be corrected.

FVD: Compensatory Mechanisms:

Aldosterone (comes from adrenals) and causes reabsorption of Na+ and H2 O when serum osmolality is too high.
Renin/ADH/Aldosterone help correct FVD.

2.

FVE: Compensatory Mechanisms:

Atrial and B type Natriuretic Peptides: initiated when heart muscle fibers in atria stretch.
They send signal to kidneys (no release of ADH/Aldosterone) and Pituitary (no release of ADH)

Fluid Imbalances
Normal=
275-310
FLUID VOLUME DEFICITS; FVD
Dehydration:
(Hypertonic
dehydration)

Osmolality:

Vascular loss: hypotension, tachycardia

Cellular Loss: dry mucous membranes/
skin turgor.

fluid and solutes

Osmosis will move fluid from area with more
fluid to less fluid./vascular and cellular loss of
fluid.

> 310

Hypovolemia:

Osmolality:

FVD/Isotonic
Fluid loss.

275-310 normal

(choice of IV fluids determines which to

treat or both)
No fluid shifting

Loss of fluid and solutes proportionately

N/V/D
Inadequate intake of
fluids
Exercise without fluid
replacement
Hemorrhage
Shock
CO
hypoxic

circulating
volume.
FLUID VOLUME EXCESS: FVE
Hypervolemia:

Osmolality:

FVE/Isotonic
Fluid excess

275-310 normal

Water
Intoxication

2x circulating
volume
Osmolality:
< 275

Retention of fluid and solutes in

proportionate amounts.

If fluid becomes excessive it will move to

interstitial (3rd spacing) causing peripheral
edema or lungs resulting in pulmonary
edema

Weakening heart
CHF

Retention of fluid in greater amounts

than solutes.

Fluid movement into cells is problematic:

Brain cells: cerebral edema

Excessive intake without

output

Osmosis will move fluid from area with

more fluid to less fluid. Vascular and
cellular increase of fluid.

Solutes/electrolytes :
K+ loss = cardiac arrhythmias

Cells expand/burst

ELECTROLYTES:
If fluid is then all electrolyte levels (concentrated)
If fluid is then all electrolyte levels (dilute)
Osmolality

BUN

Creatinine

Hematocrit

Urine Na+

Low pressure = low fluid volume

High pressure = high fluid volume
CV pressure
PA pressure
Placed in
subclavian/Internal
jugular

275-310

10-20

0.6 1.5

37 54%

50 - 130

Machine at same
level as atria.
4 - 10
Fluid Volume
related

Swan or Balloon
Wedge

Systemic
Arterial
Pressure
Arterial Line

25/9
Mean of 15
Fluid Volume
related

Fluid Volume
related

BMP: gives anion gap for Critical Care Patients: means there is not a balance of + and - electrolytes. The ranges may be normal but
specific electrolytes dont match. This may explain why as a nurse you are giving K+ to a patient with normal ranges.
ELECTROLYTES IMBALANCES / REASONS
HYPO:
o
o
o
o
o
o

HYPER:

Inadequae intake
Excessive loss via secretion
Water gain (dilute)
Shifting into compartments (too much K+ goes into cell, insulin)
Hormonal disorders
Imbalance with other electrolytes with inverse proportions (Ca/PO4 )

********* ********Remember if K+ is high = acidosis

o
o
o
o
o
o

Replacement therapy (PO/IV/IM)

Increase in dietary intake
Restrict water intake
Correction of hormonal disorder
Correction of other electrolyte imbalances
Medications.

Remember that hyperglycemia/ DKA = hyperkalemia *********

********* ********Remember if K+ is low = alkalosis *******************

ELECTROLYTES
Electrolyte

S/Sx

Hypo

S/Sx

Altered Mental Staus: Hallmark

N/V/D
Weakness
Muscle weakness

< 135

Altered Mental Status: Hallmark

N/V/D
weakness
Muscle Weakness

Hyper
Na+
135-145

> 145

K+
3.5- 5.0

> 5.0

< 3.5

**Predisposed to Digoxin Toxicity **

Take apical pulse- <60 get order for dig level.
Anorexia/Nausea

Think pt. on
digoxin and lasix
for CHF.
EKG: tall tented T waves/ HYPER High T waves
Mag

> 2.5

1.5 -2.5

Respiratory Rate
Heart Rate/bradycardia
DTR (less than 2)

EKG: any change that falls BELOW baseline/ ST depression.

< 1.5

Think pregnant mom put on Magnesium Sulfate.

Too high levels can cause these symptoms .

Think the opposite of the Mag toxic mom. Climbing the walls.
The mom has low mag so we add Magnesium to increase
supply. Low mag = seizures

Calcium Gluconate is antidote.

Calcium
9-11 or
4.5 5.5 ionized

> 11

Phosphorous
2.8- 4.5

> 4.5

Think Na+ too

because Na+Clare paired up.

<9

Cardiac contractility:
Constipation (give Ca to PO4 )
Hypophosphatemia

Think : Renal
Issue
Chloride
96-106

Hyporeflexia (same as hypermagnesemia)

Hypocalcemia
Anorexia
Altered Mental Status

DTR ( +3 or +4)
Tetany
CLonus
+ Chvosteks/Trousseaus

Hyperreflexia (same as Hypomagnesemia)

Only electrolyte in clotting cascade: prolonged clotting
More prone to osteoporosis/ loss bone density

< 2.8

Hypercalcemia
Anorexia
Altered Mental Status

< 96

Muscle Cramps

GIVE: Phoslo
> 106

Altered LOC/weakness
THINK: Na+ if something is wrong with Clprobably something is wrong with Na+

THINK: Na+ if something is wrong with Cl- probably

something is wrong with Na+

TONICITY OF SOLUTIONS
Isotonic: cells dont shrink or swell
Normal Osmolality 275-310
0.9 % sodium chloride (NS)
LR
5% dextrose injections (D5W)

Hypotonic: cells swell, cellular dehydration

Below normal osmolality < 275
0.45% sodium chloride (1/2 NS)
0.22% sodium chloride (1/4 NS)
Hypertonic: cells shrink,
Above normal osmolality > 310
5% dextrose and 0.9% sodium chloride ( D5NS)
5% dextrose LR (D5LR)
5% dextrose 0.45% sodium chloride (D5 1/2NS)
5% dextrose 0.22% sodium chloride (D5 NS)

Osmotic Diuresis
Occurs with TPN: hypertonic fluid
Must start slow at D20 and add 24 hrs. worth of electrolytes, fats, etc.. = very thick, sticky fluid put in pt. vascular space. May notice
UO is increasing of up to 3000 per shift which is 2x the normal 1500. Why? The concentration of vascular space is making cells give
up their water so pt. is getting nutrition at expense of cellular dehydration.
Correct this problem by diluting TPN. Run concurrent hypo at same time as TPN to dilute concentration in vascular space: An
example order may say: start TPN, increase by 10ml per shift to goal rate of 85ml. This allows pancreas to catch up to allow for
increasing sugar from TPN. Slowly taper up. It may also say: Run NS concurrently for a total rate of 125.
So if you start TPN at 30ml then the NS would run at 95ml.
At next shift TPN at 40ml then the NS would run at 85ml.
Once at goal rate of TPN at 85ml then NS would run and stay at 40.
One tapers up and the other tapers down. Always taper back down to avoid hypoglycemic reaction.
Occurs with Acute Renal Failure:
Occurs in head injuries when we use osmotic diuretics to cerebral edema.