Transcript Cellular Paramedicine

Fluids / Electrolytes
Principles of Homeostasis
Silver Cross EMSS CME
October 2012 3rd Trimester
Our Agenda Today
• System news!
• Our main topic today: Fluids and Electrolytes
• CHF vs. COPD… a quick but important
refresher
• (ALS) Strip O’ the Month – PEA/Asystole
System News!
• Please Press Take! For everything you remove
from the Pyxis, you must press “take”. 5 IV
catheters, 5 presses. 3 canulas, 3 presses. Etc.
The supply people can’t restock the machine
properly otherwise and it leaves your fellow
providers short of supplies.
• IDPH fees and online process for license apps
and renewals went into effect September 1st.
Body Systems Working Together
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Integumentary
Skeletal
Muscular
Lymphatic
Respiratory
Digestive
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Nervous
Endocrine
Cardiovascular
Renal / Urinary
Reproductive
Body Systems
• Parceling out vital
functions to several
different organ
systems results in
interdependence of
all body cells.
• No individual’s organ
systems work in
isolation.
Necessary Life Functions
• Must be able to maintain their boundaries.
Internal environment must remain distinct from
the external environment
• Single cell organisms
• Human beings
Necessary Life Functions
• Movement
by muscles and the skeletal system
• walking, running, writing
also other movement
• blood moved through cardiovascular system
• foodstuffs moved through digestive system
• urine moved through urinary system
at the cellular level
• the ability of cells to move by shortening (contractility)
Necessary Life Functions
• Responsiveness
the ability to sense changes (stimulus) in
the environment and respond to them
• reflex - like touching a hot stove
• carbon dioxide levels and respiratory rate
Necessary Life Functions
• Digestion
the process of breaking down ingested
foodstuffs to simple molecules that can
be absorbed into the blood.
• Nutrient rich blood is then distributed to all
areas of the body
• Amoeba
– a single celled “digestion factory”
Necessary Life Functions
• Metabolism
a broad term that includes all chemical
reactions which occur within body
cells
• catabolism – breaking down
• anabolism – building up
• all catabolism + all anabolism equals
metabolism
Necessary Life Functions
• Excretion
the process of removing wastes
from the organism
• get rid of non-useful substances
• toxins
Necessary Life Functions
• Reproduction
– cellular
• cell division
• Mitosis and meiosis
– organism
• eggs and sperm
Necessary Life Functions
• Growth
increase in size of a body part or the organism
• usually the result of an increase in the number of
cells
• may be due to increased size of existing cells
• in any case it is the result constructive activities
occurring at a rate faster than destructive activities
Survival/Physiological Needs
•
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nutrients
oxygen
water
normal body temperature
atmospheric pressure
The body has a natural tendency to keep the
internal environment constant.
Temperature Water
Sugar
Blood Volume
Oxygen
Carbon Dioxide
Heart Rate
Respiratory rate
Blood Pressure
HOMEOSTASIS
Homeostasis
• Greek for ‘like fixed conditions’
• Walter Bradford Cannon (1871-1945)
established our basic understanding about
the global function of the adrenal
gland/sympathetic nervous system axis
Homeostatic Control Mechanisms
• Variable
• Receptor/affector
• Control center
– Brain
• Effector
• Negative feedback
furnace thermostat
• Positive feedback
bleeding
delivery
hormone balance
Negative Feedback Loop
• A stimulus produces a response that
opposes the original stimulus
– Thermostat controls heating/cooling
• When the room temperature rises/falls, the
thermostat (control center) triggers an EFFECTOR
response that restores normal temperature
• Can be either to warm up or to cool off
Brain’s Negative Feedback Loop
• The brain is the control center for
regulation of body temperature
• Receptor-sensors in skin/cells of
thermoregulatory center (affector pathway)
sense temperature outside the normal
acceptable range
Brain’s Negative Feedback Loop
• The brain sends a command, via
EFFECTOR pathways for the skin and
sweat glands to react and balance the
heat in the body to regain homeostasis
Positive Feedback Loop
• Initial stimulus produces a response that
reinforces a stimulus
– EX: thermostat wired so when temperature is
low, the heater turns on rather than the air
conditioning
• Initial stimulus (decreased heat/temp) causes
response (heater on) and heat stimulus
strengthened instead of cooled
Thermoregulation
• If the thermoregulation center in the brain
is unable to function, the body would die
from either hyperthermia or hypothermia
Homeostatic Control Mechanisms
• Agonist
causes a
physiological
response
“-mimetic”
• Antagonist
blocks a
physiological
response
reverses or
opposes
“-olytic”
FLUIDS
Water
• Water is an essential medium which forms
the chief environment in which cells live
and function
• Transport medium for nutrients, hormones,
blood cells and waste products
• Regulates body temperature
Some additional quick terminology...
intra
within
extra
outside of
cellular
pertaining to cells
vascular
pertains to vessels
Hyper-
high / increased
Hypo-
low / decreased
heme, hema,blood
hemo
-carbia
carbon dioxide
WATER
• Most abundant substance in the human body
• 60% of total body weight
• Fluid Compartments
75%
Intracellular
Extracellular
25%
• intravascular
7.5%
• interstitial
17.5%
Fluid compartments of the body.
Intracellular Fluid (ICF)
• Basic unit of organ structure
• Contains nucleus, mitochondria,
endoplasmic reticulum and lysosomes
Extracellular Fluid (ECF)
• Water that surrounds the cell/outside the
cell
• Interstitial fluid – bathes cells
• Intravascular fluid – plasma portion of
blood found in circulatory system/in the
vessel.
– Plasma carries RBC, WBC, platelets,
electrolytes, hormones, waste, etc.
Water Intake
• How do we get it into
our bodies?
Well of course drinking
water and other fluids.
From eating fruits and
vegetables
Oxidative metabolism
Water Intake
• But also by eating foods not typically thought of
as containing a great deal of water
– Actual fluids
=1640cc/day
– Food
=750 cc/day
– Oxidative metab.
= 350 cc/day
» TOTAL
2,740 cc/day
Water Output
• All the water excreted from the body as
urine but also:
Water excreted including the lungs, skin and
intestines
Sources of
OUTPUT
How much
intake fluid is
required?
Insensible
losses
• Urine
1700 cc
• GI tract
150 cc
• Sweat
150 cc
• Vapor in resp.
400 cc
2400 cc
HOMEOSTASIS
Monitoring Water Balance
• Daily weight
– 1 kg (2.2lbs) means a fluid loss or gain of 1
liter of fluid
– Takes 3,000 ml of ECF deficit to produce
signs of dehydration (4% of total body wt.)
Abnormal decrease in total body water
• Insensible losses (saliva, sweating, respirations)
such as from fever states
• Sweating
• Internal losses (Third Spacing)
• Plasma losses (Burns, surgical drains, fistulae)
• Gastrointestinal losses (diarrhea, vomit)
• Implies loss of electrolytes (increased metabolic rate)
Signs and Symptoms
• Orthostatic hypotension
• Dry mucus membranes
• Absence of normal sweating
• Thirst
• Hematocrit elevated in pure
• Poor skin turgor
dehydration, may be decreased if
actively bleeding
• Tachycardia
• Hypotension
• Confusion, Coma, Death
• In infants, sunken fontanel,
lack of tears, fewer diaper
changes
• Decreased urinary output
• Dark urine
• Increased respiratory rate
DEHYDRATION
Treatment
ALS/ILS
• Get fluid in
• IV isotonic solution
We’ll get to this part later!
DEHYDRATION
An excess of total body water
• May aggravate Congestive Heart Failure
• Chronic overhydration can cause renal failure
The major sign of over-hydration is EDEMA.
OVERHYDRATION
Signs and Symptoms
Hypertension may indicate overload
Jugular Vein Distention (JVD)
Tachycardia
Dependent edema / crackles
Hematocrit decreased
Shortness of Breath
Headaches, confusion, coma, seizures
OVERHYDRATION
Treatment
GET THE WATER OFF!
How would you do this as a paramedic?
How does the body do this on its own?
OVERHYDRATION
Kidney Function
• Regulates blood volume/blood pressure
– Adjusts volume of H2O lost in urine
– Regulates hormones erythropoietin & renin release
• Regulates concentration of plasma ions of Na++,
K+, Cl- by controlling amount lost in urine
• Controls blood pH by controlling loss of H+ ions
and HCO3- ions concentrated in urine
Production of Urine
• Blood flows through the glomerulus
• Glomerular pressure pushes fluid out of the
glomerular capillaries and into the Bowman’s
capsule at the rate of 180 L / day
• Peritubular capillaries reabsorb water,
glucose, sodium and other nutrients and put it
back in the general circulation
• Peritubular capillaries also secrete hydrogen
ions, potassium ions and ammonia
Urine Regulation
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Aldosterone
ADH
Atrial natiuretic factor hormone
Prostaglandins and kinins
Aldosterone
• hormone secreted by the adrenal gland
• stimulates tubules to reabsorb sodium
salts to attract and hold water
ANTIDIURETIC HORMONE (ADH)
• Secreted in the posterior pituitary gland
osomoreceptors are stimulated by an increase in the
osmolality of body fluids
atrial receptors are stimulated by a fall in venous blood
volume
makes distal and collecting tubules permeable to water,
thus increasing water reabsorption
water is therefore retained in the presence of ADH
Increased ADH production
• high plasma osmolality compared to interstitial fluid
• low circulating volume sensed by baroreceptors
• stimulation of sympathetic nervous system
• Drugs-- morphine, oxytocin, diabinase
• head injuries, meningitis - syndrome of inappropriate ADH
Secretion
Decreased ADH production
• Decreased production of ADH results from-Decreased plasma osmolatity
Increased circulating volume
Alcohol consumption
Caffeine
Cold
Atrial Natiuretic Factor/Peptide
ANP
• Secreted from cells in the right atrium of
the heart when pressure in the right atrium
increases
• ANF inhibits ADH secretion and reduces
the ability of the kidney to concentrate
urine
Prostaglandins & Kinins
• Formed in the kidneys
• Promote vasoconstriction and increased
capillary permeability
• Part of the inflammatory process
• Influence the rate of filtrate formation and
sodium ion reabsorption
Can’t you make it any easier?
• Kidneys have two options-Retain water, put it back in the intravascular
space.
-or-
Dump (water) urine into the urinary bladder
Administration of Diuretic Therapy
Furosemide (Lasix)
inhibits sodium and chloride reabsorption by the loop
of Henle
also causes venous dilation
used primarily for acute pulmonary edema & CHF
Furosemide (Lasix)
• Contraindicated in pregnancy
• Precautions
dehydration
electrolyte depletion (hypo-kalemia)
contributing to digitalis toxicity
• Side effects
hypotension
ECG changes
chest pain
electrolyte deficiencies
• Dosage
20-40 mg IVP (at medical control discretion)
ELECTROLYTES
• Related to 5 physiologic processes
Water distribution
Osmotic pressure
Neuromuscular activity
Acid/Base Balance
Support of cellular metabolism
Electrolytes
• Chemical
substances (ions)
that dissociate
charged particles
when placed in
water and are
usually measured in
milliequivalents
(mEq/L).
ELECTROLYTES
• The Endocrine system and the kidneys are the
primary way of regulating fluids and electrolytes.
Osmoreceptors in the hypothalamus monitor fluid
concentrations.
Hypothalamus secretes ADH
ADH stored in the Posterior pituitary gland
Kidneys release Renin which in turn controls release of
Aldosterone
Aldosterone helps controls pH, electrolyte and fluid balance
ELECTROLYTES
Anions have a negative charge
Cations have a positive charge
ESSENTIAL CATIONS
• SODIUM (Na+)
Prevalent in the extracellular fluid
Normal range is 135-145 mEq/L
Helps regulate distribution of water
Helps transmit nerve impulses
Na+
Na+
Na+ +
Na
Na+
Na+ +
Na +
Na
+ +
Na+ NaNa
Na+
Cell
Na+
Na+
Na+ + +
Na Na
Na++
Na Na+
Na+ +
Na
Na+
Sodium (Na+)
• Changes in
concentration
stimulate pituitary
gland to secrete
or withhold ADH
• Electrolyte of
ventricular
depolarization
Sodium (Na+)
• Kidneys are the chief regulator of Na+
• Moves rapidly between vascular and
interstitial spaces
• Rapid movement of water (in and out of
cell) causes concentration of Na+ to
change quickly, even though Na+ does not
cross cell wall membranes easily
Hyponatremia
• Water retention
– ECF becomes hypotonic to the cell and water
shifts into ICF. This causes  blood volume
and a large portion of the body fluid in the cell
= pitting edema
– Osmolality  r/t  Na+ resulting in fluid
(osmosis) movement from ECF to ICF
Hyponatremia
• vomiting and diarrhea
• 3rd space losses of ECF from peritonitis,
ascites, ileus
• CHF, peripheral edema
• Excessive use of oral water intake
• When crackles/rales are present volume is
 at least 1500 ml from normal
Hyponatremia
• Signs and symptoms
– Mental confusion, delusions
–  blood volume,  BP, tachycardia
– Muscle weakness, abdominal cramping
– Flat neck veins
– Flushed skin, increased body temperature
– Headache
– Dry mucous membranes
Hyponatremia
• Treatment
– IV normal saline (isotonic) for dehydration
– Diuretics for CHF with Na+ deficit
What are some of the common diuretics patients
take?
Hypernatremia
• Sodium excess, water loss without salt
loss
• What happens?
– ECF becomes hypertonic and water shifts
from ICF to ECF until equal
Hypernatremia
• Decreased intake of fluids, especially in
hot weather
• Febrile states, increased sweating
• Copious watery diarrhea
• Salt & H2O retention related to inability to
excrete Na+ r/t starvation, severe illness,
dehydration
Hypernatremia
• Sodium reabsorption from steroid use
•  capillary permeability during
inflammation or allergic process
•  plasma proteins in nephrosis or
cirrhosis or from renal failure
Hypernatremia
• Results from burns, excessive sweating
and DKA (diabetic
ketoacidosis/hyperglycemia
• Hypothyroidism, Cushing’s Syndrome and
toxemia during pregnancy
Hypernatremia
• Drugs that  Na+
levels
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–
Diuretics
Heparin
NSAIDS
antidepressants
• Drugs that  Na+
levels
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–
–
–
–
Steroids
Antibiotics
Cough meds
Laxatives
Oral contraceptives
Hypernatremia
• Treatment
– Sodium restriction
– diuretics
ESSENTIAL CATIONS
• Potassium (K+)
Prevalent in the intracellular fluid (ICF)
Key role in the transmission of electrical
impulses/cell excitability
Extracellular
Intracellular
Na+
K+ K+ Na+
K+
K+
K+
K+
Potassium (K+)
• Normal range 3.5 – 5.2 mEq/L
• Renal failure causes K+ to not be flushed
out normally causing toxicity
• K+ continually moves in and out of cells
• Entrance into cell depends on normal
metabolism and utilization of glucose
Hyperkalemia
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•
•
Renal failure, burns
Tissue trauma, massive crush injuries
Excessive K+ intake
Respiratory/metabolic acidosis
When tubules excrete H+ ions to  pH
levels, K+ accumulates in the blood
Hyperkalemia
• Signs/symptoms
– Muscle weakness, irritability
– Nausea, diarrhea
– Intestinal colic, muscle cramp & pain
– EKG changes
• Wide QRS, peaked T wave, depressed S-T
segments, no P wave, cardiac arrest/asystole
Hyperkalemia
• Treatment
– Elimination of K+ intake
– IV infusion of normal saline in large volume
– CaCl- IV to antagonize K+ affects on
myocardium
– Glucose and insulin to drive K+ into cells
Hypokalemia
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K+ deficit caused by excessive loss of K+
Metabolic alkalosis
Diuretic therapy
Acute alcoholism
Uncontrolled diabetes
Excessive perspiration
Hypokalemia
• Signs/symptoms
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Apathy, lethargy, muscle weakness
Tachycardia
Abdominal distention/gas
Weak pulse
DIB, shallow respirations
Metal depression
EKG – flat T wave, depressed ST segment, VF
Hypokalemia
• Treatment
– KCl- (potassium chloride)
– IV lactated ringers
Potassium (K+)
• Drugs that  levels
– Diuretics
– Laxatives
– ASA
• Drugs that  levels
–
–
–
–
Heparin
Epinephrine
Mannitol
Histamines
ESSENTIAL CATIONS
• Calcium (Ca++)
Plays major role in muscle contraction
Plays major role in nerve impulse transmission
• Assists with Na+ and K+ crossing cell
membrane
Extracellular
K+
Ca++
Na+
Intracellular
Calcium Ca++
• Normal range 9.0-10.5 mg/dl
• Helps to coagulate blood
• Maintains normal heart depolarization of
the SA and AV nodes
• Maintains plasma membrane permeability
Calcium (Ca++)
• Gate to allow Na+ to enter into cell for
depolarization (contraction) to occur.
Increased levels of Ca++ block this gate,
leading to decreased cell permeability and
depressed peripheral nervous system
Calcium (Ca++)
• Regulated in the bone, intestine and
kidney
• Parathyroid hormone (PTH) and vitamin D
maintains levels of Ca++. PTH is released
in response to low Ca++ and renal tubules
and intestine reabsorb Ca++ through
Vitamin D
Hypercalcemia
• Increased Ca++ absorption
• Prevention of renal excretion
• Hypercalcemia which decreases cell
membrane permeability resulting in
decreased neuro-muscular excitability
Hypercalcemia
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•
•
•
Renal disease
Excessive ingestion of milk or Vit. D
Prolonged immobilization; bed rest
Bone cancer (Ca++ is released from the
bone in large amounts)
• hyperthyroidism
Hypercalcemia
• Signs and symptoms
– Fatigue, depression
Hypocalcemia
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Massive infections, peritonitis, pancreatitis
Chronic renal failure
Burns
Hypothyroidism
Hypocalcemia
• Signs/symptoms
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Muscle cramps
Muscular excitability, twitching, tetany
Signs of malnutrition, chronic alcoholism
Anxiety
Increased GI motility (N,V,D)
Laryngeal spasms, hypoxia
EKG – prolonged QT interval
Decreased BP
Hyperventilation, increased respirations
Testing for Hypocalcemia
• Just for fun, don’t try this!!
– Trousseau’s Sign – Place BP cuff on arm and inflate
to exceed systolic pressure for 3 minutes. Note
carpal spasm with contraction of thumb and fingers.
Note inability to open the hand.
• Hyperexcitaility is due to decreased Ca++ that is enhanced
by the ischemia
THIS IS ONLY A POTENTIAL TEST….DO NOT DO THIS IN
THE FIELD
Hypocalcemia
• Treatment
– IV fluids, normal saline
– Calcium gluconate, CaCl- or Vitamin D
– To reverse hyperventilation (alkalosis), have
patient rebreathe CO2
ESSENTIAL CATIONS
• Magnesium (Mg++)
Necessary for
several biochemical processes,
neuromuscular
transmission/excitability, metabolism of
carbs and proteins
Magnesium (Mg++)
• Normal range 1.2 – 2.0 mEq/L
• Intracellular cation that is bound to ATP
energy and found mostly in bone (67%)
and muscle (20%)
• Modifies enzyme activity
• Found in legumes, grains, green veggies,
meat & seafood
Magnesium (Mg++)
• Essential for glycolysis which is necessary
for ATP production
• Activates the Na/K ATPase pump
– More on this in cardiology!!
Magnesium (Mg++)
• Therapeutic effects
– Bronchodilating properties for acute asthma
– Stops seizure activity in eclampsia
– Treat alcoholism withdrawal
– Treats tachycardia in digoxin toxicity
– Acute MI for increased resuscitation outcome
(pt’s generally have low levels)
Hypermagnesemia
• Very rare
• Chronic renal failure
• Laxative/cathartic abuse
– Antacids, maalox, pepto, milk of magnesia
Hypermagnesemia
• Signs/symptoms
– Respiratory depression
– Lethargy, confusion,
– GI r/t nausea and vomiting
– Uncontrolled diabetes
– EKG – short QT interval, prolonged PR and
QRS intervals, bradycardia and heart blocks
Hypermagnesemia
• Treatment
– Control diabetes and GI loss
– Treat cardiac dysrhythmias
– Administer Ca++
– dialysis
Hypomagnesemia
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•
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•
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Decreased dietary intake, alcoholism
Fistulas
GI disorders
AMI, post CABG
DKA due to diuresis
Decreased K+
Hypomagnesemia
• Signs/symptoms
– Weakness, irritability
– Tremors, tetany
– Vertigo, seizures
– HTN, hx of AMI
– Increased systemic vascular resistance
(tachycardia)
– Insulin resistance
Hypomagnesemia
• Treatment
– Administer Magnesium Sulfate (MgSO4)
Magnesium
• Drugs that  levels
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–
–
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Antacids
Thyroid meds
Antibiotics
diuretics
• Drugs that  levels
– Insulin
– antibiotics
ESSENTIAL ANIONS
• Chloride (Cl-)
Balances the positive charge
associated with the cations
Plays major role in fluid balance and
renal function by maintaining
osmotic pressure
Close association with sodium
Chloride (Cl-)
• Normal range 90-110 mEq/L
• Extracellular anion
• Combines with H+ ions to produce
hydrochloric acid to aid in acid/base
balance
Hyperchloremia
•
•
•
•
Dehydration
Eclampsia
Metabolic acidosis, respiratory alkalosis
hyperthyroidism
Hyperchloremia
• Signs/symptoms
– Lethargy, weakness
– Deep respirations
– Kussmaul’s respirations
– Decreased cognition
Hypochloremia
•
•
•
•
•
Overdhydration
CHF
Burns
Metabolic alkalosis, respiratory acidosis
burns
Hypochloremia
• Signs/symptoms
– Shallow respirations
– Decreased BP
– Tetany, hyperexcitability
Chloride
• Drugs that  levels
– Cortisone
– Estrogen
– Anti-inflammatory
• Drugs that  levels
– Bicarbonate
– diuretics
ESSENTIAL ANIONS
• Bicarbonate (HCO3- )
Principle Ion of the Buffering System
• Controlling pH levels of the body
• ECF
Bicarbonate (HCO-3)
•
•
•
•
Normal range 135-145 mEq/L
Intracellular
Renal component of acid/base balance
Binds H+ ions to form carbonic acid in the
process of buffering metabolic acidosis
caused by anaerobic metabolism and
lactic acid production
Bicarbonate
• Carbonic acid rapidly crosses into cells
causing a worsening of intracellular
hypercarbia (too much carbon) and
acidosis which depresses myocardial and
cerebral function
• Bicarbonate crosses into cells more slowly
Sodium Bicarbonate
• Medical indications for NaHCO3
– Late in cardiac arrest after defib, CPR, ET,
oxygenation/ventilation and at least 2
administrations of epinephrine
– Overdose with tricyclic antidepressants (binds
Na+ channels)
– Alkalinize urine in drug overdoses
Sodium Bicarbonate
• Effects of administration
– Fluid retention (cardiovascular)
– Tissue necrosis at IV site (skin)
– Can cause metabolic alkalosis (electrolyte)
Sodium Bicarbonate
• IMPORTANT NOTE
– Do not mix NaHCO3- with calcium agents as it
will precipitate
– Monitor for fluid overload
• Crackles
• Pink, frothy sputum
• Peripheral edema
Fluid and Electrolyte Imbalance
• There comes a point where the body
(especially the kidney) can no longer
maintain interrelationships of fluids and
electrolytes essential to normal function
resulting in imbalance
– Your job is to prevent further imbalance by
recognizing the s/s AND knowing what
therapy to administer
Problems with Fluids and
Electrolytes
• Result from
– Volume disturbance (too much/too little)
– Irregularities in transportation of fluid (CHF,
shock)
– Ratio of fluid and electrolytes imbalanced
(acidosis, alkalosis)
– Shifts of fluid to the wrong places
(edema/ascites)
SEMIPERMEABLE MEMBRANES
• Cell membrane which allows passage of certain
substances and restricts the passage of others.
Allows
• Oxygen, Carbon Dioxide, Water
Restricts
• Proteins, Glucose
Only
capillaries
have
walls thin
enough to
let solutes
pass
through.
Colloids vs. Crystalloids
• Colloids
• Contains proteins or high molecular weight (large)
molecules
salt-poor albumin, dextran
• Crystalloids
• Primary compounds used in pre-hospital
• Lactated Ringers, Normal Saline, D5W
COLLOID SOLUTIONS
• Advantages
• Disadvantages
Requires less solution
to replace vascular
volume
More expensive
Maintains colloid
oncotic pressures
Allergic reactions
Effective as volume
expanders
Pulmonary
complications
Interference with
platelet function
Renal complications
CRYSTALLOIDS
• Advantages
Inexpensive
Readily available
Causes no allergic
reactions
No infectious disease
transmission
Effective volume
expanders
Cleared by lymphatics
• Disadvantages
Need large amounts of
solution to replace
vascular volume
3 to 1 ratio -adult
20 cc/kg peds
We’re going to be especially interested in three spaces.
Where do we put fluid?
Intracellular space
Interstitial space
Intravascular space
Via intravenous catheters
TONICITY
(Concentration of molecules)
• ISO
tonic
• Hyper
Same
More
tonic
• Hypo
Less
tonic
Number of
molecules
Tonicity
• The degree of concentration (osmolarity)
of a solution depends on the amount of
solutes (particles) dissolved in water
• Tonicity controls movement of water
across the membrane
Tonicity
Interstitial
Cel
l
Isotonic (Iso means same right?)
Interstitial
Cel
l
TONICITY
• HYPERTONIC -- A state where a
solution has a higher solute
concentration on one side of a
semipermeable membrane compared to
the other side.
Cell
Interstitial
Intravascula
r
Interstitial
Cel
l
TONICITY
• HYPOTONIC -- A state where a solution
has a lower solute concentration on one
side of a semipermeable membrane
compared to the other side.
Cell
Interstitial
Intravascular
Interstitial
Cel
l
Hypotonic
Interstitial
Hypertonic
Cel
l
What is the tonicity of these?
Interstitial
Cel
l
?
?
Interstitial
Cel
l
Water and Electrolyte Distribution
• One of the forces that govern the movement
of water/electrolytes is passive transport
• Passive transport moves substances down
their concentration gradient through the
appropriate transport proteins
Passive Transport
• Osmosis
• Diffusion
• Facilitated Diffusion
PASSIVE TRANSPORT MEANS NO ATP
ENERGY IS REQUIRED FOR MOVEMENT
Ex: fish that swim with the current
OSMOSIS:
The movement of water across a
semipermeable membrane from an area of relatively
lower solute concentration to an area of relatively higher
solute concentration.
Interstitial
Cel
l
Osmosis
• Water moves along the concentration gradient
from an area of low solute concentration to an
area of high solute concentration to achieve
equilibrium
• The force that makes the water move is called
the osmotic pressure
Osmosis
Osmotic Pressure
• The amount of pressure required to stop
osmosis and water moving across the
semipermeable membrane
Osmosis
• How are patient’s affected by osmosis?
– Increased ICP due to cerebral edema
• Give manitol as a hypertonic solution as the
particles will pull water
– Diabetic ketoacidosis (DKA)
• Increased glucose make plasma hypertonic to
interstitial fluid
• Fluid moves from interstitial space to vascular
space
Osmosis
• How are patients affected by osmosis?
– Can experience dehydration + acidosis
• Give infusions of normal saline (isotonic) to dilute
the plasma and rehydrate interstitial compartment
DIFFUSION: The movement of solutes across a
semipermeable membrane from an area of relatively
greater solute concentration to an area of relatively
lower solute concentration.
Interstitial
Cel
l
Diffusion
• Spontaneous process that distributes
molecules
• Molecules continually are in motion and
collide. The collisions cause molecules to
change direction and spread out until they
are uniformly distributed
Diffusion
• Move down the concentration gradient
because they diffuse from regions of
higher concentration to lower
concentration
• Solutes move more slowly than water
• Ex: O2 and CO2 in the lungs
And now for something Completely
Different!
• Let’s take a few minute break, then come
back.
CHF vs. COPD
• We are seeing a lot of this in narratives lately:
• “Patient exhibiting difficulty breathing with
wheezes. Patient given Albuterol via
nebulizer, no change in condition.
CHF vs. COPD
• Then as we read further, we see information
like this:
• “Patient’s BP 160/100. Patient hx
CHF/pulmonary edema/left-side heart failure.
Patient EKG atrial fibrillation. Patient meds
lasix, Cardizem, coumadin.”
RED FLAGS!!!
•
•
•
•
History of CHF/pulmonary edema and/or afib
High blood pressure
Trouble breathing
Noisy lungs
Consider CHF!
• Red flags indicate high suspicion for CHF, NOT
COPD
• Nebulized albuterol is not going to help.
– Will just raise heart rate and work heart further
– Might help a tiny bit if the patient has co-morbid
COPD or asthma, but not much
• You can always throw an in-line neb on the CPAP if you
suspect a bit of COPD too.
But remember: CHF is not a
respiratory issue
• Congestive heart failure and pulmonary
edema are cardiac issues.
• Need a cardiac solution
• Your go-to’s:
– CPAP
– Nitro
– Lasix and Morphine with medical control approval
• CPAP and nitro are miracle-workers in CHF!
Then why do we hear wheezing?
• In the field, occasionally hard to differentiate
between wheezes and crackles/rales.
• Wheezes are musical
– More common during expiratory phase
• Crackles, well, crackle (and pop and click and
bubble)
– More common during inspiratory phase
Online!
• If you have a moment, Google lung sounds.
It’s a great way to learn the difference!
• An example of a good lung sound site:
– http://www.stethographics.com/main/physiology
_ls_introduction.html
Strip O’ the Month
• Asystole/PEA
Asystole (Cardiac Standstill)
• Asystole is a total absence of ventricular electrical activity
– There is no ventricular rate or rhythm, no
pulse, and no cardiac output
• Some atrial electrical activity may be evident
– “P-wave” asystole
Asystole – ECG Characteristics
Rate
Ventricular usually not discernible but atrial activity may
be observed (“P-wave” asystole)
Rhythm
Ventricular not discernible but atrial may be discernible
P Waves
Usually not discernible
PR Interval
Not measurable
QRS Duration
Absent
Asystole – Causes
• Pulmonary embolism
• Acidosis
• Tension pneumothorax
PATCH-4-MD
PATCH-4 MD
• Cardiac tamponade
• Hypovolemia
• Hypoxia
• Heat/cold (hypothermia/hyperthermia)
• Hypokalemia/hyperkalemia (and other electrolytes)
• Myocardial infarction
• Drug overdose/accidents (cyclic antidepressants, calcium
channel blockers, beta-blockers, digoxin)
Asystole – Intervention
• Confirm the absence of a pulse
• Perform immediate CPR
• Confirm the rhythm in two leads
• Consider possible causes of the rhythm
• Pharm: Epinephrine 1:10,000 1mg IV/IO
• No More Atropine!!!
Pulseless Electrical Activity (PEA)
• Pulseless electrical activity is a clinical
situation, not a specific dysrhythmia
• Formerly called electromechanical
dissociation (EMD)
Pulseless Electrical Activity
• PEA exists when organized electrical activity
(other than VT) is present on the cardiac
monitor, but the patient is pulseless
PEA – Causes
• Pulmonary embolism
• Acidosis
• Tension pneumothorax
PATCH-4-MD
• Cardiac tamponade
• Hypovolemia (most common cause)
• Hypoxia
• Heat/cold (hypothermia/hyperthermia)
• Hypokalemia/hyperkalemia (and other electrolytes)
• Myocardial infarction
• Drug overdose/accidents (cyclic antidepressants, calcium
channel blockers, beta-blockers, digoxin)
PEA – Intervention
• Begin CPR
• Search aggressively for possible cause(s) of the
situation
– Often finding the right “H” or “T” can solve PEA quickly
– Most common cause: hypovolemia
• Pharm: Epinephrine 1:10,000 IV/IO
• No More Atropine!!!
• Questions?
• If you are watching live,
type into text box.
• Otherwise, feel free to
email
[email protected]
or call 815-300-7425