fluids and electrolytes
DESCRIPTION
August 10, 2011 LectureTRANSCRIPT
F L U I D SAND
ELECTROLYTES
Water overview*Water comprises about 60% -70% of the total body weight *Varies with
ageweightgender
Factors that Determine the Amount of Water Content
Age – the older we get, water content is lesser
Sex/Gender – males have more water than females
Body size/Weight – thin people have more water than chubby ones
Normal Composition in Average Man
• When a person loses more than 10% of his total body fluids,he can DIE!!!
Functions of Water in the BodyFunctions of Water in the Body• -Transporting nutrients to cells and wastes from cells • -Transporting hormones, enzymes, blood platelets, and red and white blood cells• -Facilitating cellular metabolism and proper cellular chemical functioning• -Facilitating digestion and promoting elimination• -Acting as a solvent for electrolytes and non-electrolytes• -Acting as a tissue lubricant and cushion• -Helping maintain normal body temperature
• Intracellular fluid (ICF) (60-70%)- fluid within cells- K is the major component
• Extracellular fluid (ECF) (20-30%)- fluid outside cells- Na & Cl
Two Compartments of Fluid in the Body
Interstitial – between the cellsIntravascular – inside the blood vesselTranscellular – CSF, saliva, GIT secretions and tears
LOSS of WATER
Routes and daily body fluid excretion
SENSIBLE
- An individual is aware of losing that water.
GIT / FecesWater loss through defecation/feces is 200cc
KIDNEYS / UrineWater loss through urination is 1,500ml
INSENSIBLE
- An individual is unaware of losing that water.
SKIN / PerspirationWater loss through perspiration is
600ml
LUNGS / RespirationWater loss through respiration is about 300ml – 350ml
Causes of Increased Water Loss
• Fever• Diarrhea• Diaphoresis• Vomiting• Gastric suctioning• Tachypnea
Causes of Increased Water Gain
• Increased sodium intake• Increased sodium
retention• Excessive intake of water• Excess secretion of ADH
Electrolytes
Electrolytes
Ion -atom or molecule carrying an electrical charge
cation –develop a positive charge ex. Na, K, Ca, Mg anions –develop a negative charge ex. Cl, HCO, PO4
These charges are the basis of chemical interactions inThe body necessary for metabolism and other function
• An electrolyte is a substance, that when dissolved in water, gives a solution that can conduct electricity
Functions of electrolytes-promotes neuromascular irritability
-maintenance of body fluid osmolarity-regulation of water balance-distribution of body fluids between compartments-Conduct an electric current that transports energy thoughout the body
Effects of Electrolytes
· The loss of electrolytes in the body can lead to an unbalance of fluids in the body and the pH, and a damage of the electric potential between the nerve cells that transmit the nerve signals (Encarta)
Major Electrolytes/Chief FunctionSodium- support muscle contraction and nerve
impulse transmissionPotassium — chief regulator of cellular enzyme activity and water contentCalcium- formation of bones and teeth, nerve impulse, blood clotting, muscle contraction, B12 absorptionMagnesium — support bone mineralization, protein building, muscular contraction, nerve impulse t.Chloride — maintains osmotic pressure in blood, produces hydrochloric acidBicarbonate — body’s primary buffer systemPhosphate — involved in important chemical reactions in body, cell division and hereditary traits
• Osmosisfluid move across a semi -permeable membrane from an area of low solute concentration to an area of high solute
concentration until equilibrium is achieved.
Regulation of Body Fluid Compartments
Processes:
Diffusion• The movement of particles in all directions through a
solution.• The process by which a solute (substance that is
dissolved) may spread through a solution or solvent (solution in which the solute is dissolved).
•Active Transport Physiologic pump that moves from an area of
lower concentration to higher concentration with the use of ATP.
The sodium-potassium pump is an example of active transport.
OsmolarityDescribes the concentration of solutes or dissolved particles
Filtration is the movement of solutes and solvents by hydrostatic pressure. - the movement is from an area of greater pressure to an area of lesser pressure. Osmotic pressure is the amount of hydrostatic pressure needed to stop the flow of water by osmosis -pressure exerted by proteins Hydrostatic pressure pressure exerted by fluid on blood vessel wall
Types of IV Solutions ISOTONIC – balance osmotic pressure Solute concentration is equal to that of the
serum Fluid doesn’t shift because they’re equally
concentrated and already in balance Solution has the same osmolality as the
extracellular fluid.Examples:D5W ; Normal Saline
* Doesn’t cause shrinking or swelling of the cell
HYPERTONIC SOLUTION Greater pressure than that of the blood
serum Fluids tend to move out of the less
concentrated solution into the more concentrated
Solutions have a higher concentration of solute and are more concentrated than extracellular fluids. Net movement intracellular to extracellular
Examples : 3% saline; 5% saline
* Causes the cell to shrink
HYPOTONIC SOLUTION Lesser pressure than that of the blood
serum Fluid shifts from the hypotonic solution into
the more concentrated compartment to equalize the concentrations
Solutions have a lower concentration of solutes and is more dilute than extracellular fluid . Net movement extracellular to intracellular
Examples : 1/2 Normal Saline; 1/3 Normal Saline
* Causes the cell to swell
WATER BALANCE
1. THIRST – hypothalamus
2. Hormonesa. ADH – posterior pituitary gland
- reabsorption of waterb. Aldosterone – adrenal gland
- Na retention, H2O retention
ADH Hypothalamus senses low blood volume
pituitary gland secretes ADH into the bloodstream ADH causes the kidney to retain water water retention boosts blood volume
ALDOSTERONE Produced as a result of the renin-
angiotensin mechanism Acts to regulate fluid volume
Angiotensin II stimulate the adrenal gland to release aldosterone
Aldosterone causes the kidneys to retain Na and water
Increases fluid volume and sodium levels
Renin - angiotensin system
BP decreased renin angiotensinogen
angiotensin 1
angiotensin 2
Renin – angiotensinsystem
Angiotensin 2
aldosterone peripheralvasoconstriction
increase Na reabsorption
increase water reabsorption
Increase plasma volume
increase blood pressure
VOLUME DISTURBANC
ES
FLUID VOLUME DEFICIT
Description: Dehydration in which the body’s intake is
not sufficient to meet the body’s fluid needs.
The goal of treatment is to restore fluid volume, replace electrolytes as needed, and eliminate the cause of the fluid volume deficit.
CAUSES Diabetes insipidus Fever Diarrhea Renal failure Lack of fluid intake Malnutrition Vomiting Diaphoresis
Poor skin turgor Sunken fontanels Dry mouth Scanty urine No perspiration Sunken eyeballs Weight loss No tears Weak Lethargy Dizziness Extreme thirst Dry skin
SIGNS AND SYMPTOMS
Encourage increase oral fluid intake
Administer IVF (LR or NSS)
Monitor I & O Replace fluid loss
gradually over 48 hours
Monitor Na levels, urine specific gravity
MANAGEMENT
FLUID VOLUME EXCESS Increase water
CAUSES1. Excess fluid or sodium intake
a. IV administration of NSS or LRb. High intake of dietary Na
2. Fluid and Na retention3. Fluid shift into the intravascular space
a. Burnb. use of plasma CHON or albumin
Edema Increase in weigHt Puffy eyelids Poor skin turgor Tachypnea Dyspnea
Signs and symptoms
MANAGEMENT
Monitor I & O Limit water Skin care Turn patient every 2 hours O2 Limit Na Monitor electrolyte values
ELECTROLYTE IMBALANCES
SODIUM (Na+) 135-145 mEq/L
-principal cation in ECF-average daily requirements 2-4 grms/day-responsible for:
-serum osmolality-water retention-neuromuscular activity “Na pump action”-acid- base balance
-foods high in Na-salted foods ex. ham, corned beef, cheese
etc.-regulated by the kidneys-influenced by hormone aldosterone-Chloride frequently appears in combination with Na+ion.
Hyponatremia: serum sodium level falls below 135 mEq/L. Cells become swollen.
Etiology:
◦a. loss of Na◦b. gains of water◦c. Disease states associated with ◦ ADH (Vasopressin)
Clinical manifestations(Hyponatremia) <135mEq/L
CNS changes◦ Lethargy, headaches◦ Confusion◦ Seizures◦ Coma
nausea/vomiting Hemiparesis Diarrhea, abdominal cramps Pale dry skin
Nursing Intervention
1.Evaluate precipitating cause is corrected
2.monitor Na serum level3.Evaluate clinical manifestations of Na loss
4.Maintain pts. safety5.Administer prescribed treatment, IV therapy
Hypernatremia: Serum sodium is more than 150 mEq/L. Cells shrink. Etiology:
◦ Water deprivation Excessive salt ingestion Increased insensible loss Water loss diarrhea Prolong fever or diaphoresis w/o water
replacement◦ Na containing parenteral solutions, corticosteroids,
some antibiotics◦ Near salt water drowning◦ Diabetes insipidus- polyuria, polydipsia
Clinical manifestations (hypernatremia)
Serum Na+>145 mEq/L◦ Thirst◦ Nausea and vomiting◦ Flushed, dry skin◦ Fever◦ Dry sticky membranes◦ Rough, dry, swollen tongue
CNS effects◦ Restlessness, agitation◦ Muscular twitching, tremor, hyper-reflexia◦ Disorientation, hallucinations◦ Stupor, coma
Nursing Interventions
1.Evalute precipitating cause and correct
2.Monitor serum Na level3.Evaluate clinical manifestations of hypernatremia
4.Administer prescribed treatment5.Report abnormal findings to MD6.Patient education for future prevention
POTASSIUM (K+): 3.5-5.0 mEq/L
-Principal cation in ICF, 97%-Cannot be measured in the cells-Acute abnormal levels are life threatening
1. K+<2.5 or>7.0-cardiac arrest2. K+<3.5-hypokalemia3. K+>5.5-hyperkalemia
-Responsible for:• Conduction of nerve impulses• Skeletal and cardiac muscle activity• Intracellular osmolality• Enzyme action for cellular metabolism
POTASSIUM (K+): 3.5-5.0 mEq/L
-80-90% excreted in the GIT in urine-10-20% excreted in by GIT in feces-Poorly stored in the body-Daily intake is essential (40-60mEq/L)-Foods high in K+
Green vegetables Dry fruits Nuts Meat Cocoa, brewed coffee
Hypokalemia: <3 mEq/L
Etiology
◦GI loss Diarrhea, GI suction, vomiting, laxatives
◦Renal loss K loss diuretics, aldosterone, steroids Glucocorticoids, sweat, some antibiotic
◦Shift into cells Insulin, alkalosis,TPN
◦Poor intake Anorexia, alcoholism, debilitation, neglect
Clinical manifestations ( hypokalemia)
◦Fatigue, weakness◦Cramps, restless legs◦Decreased reflexes◦Quadra-paralysis
Respiratory muscle -Renal
◦ Impaired conc. Of urine◦Dilute frequent urination◦Resistance to ADH, kidney exchange Na for
K -CV
◦Sensitivity to digoxin◦Decreased BP
Cont. Clinical manifestation (hypokalemia)
-ECG changes◦Flat T waves◦U wave◦Arrhythmias/cardiac arrest
-GI◦Decreased motility, paralytic ileus◦Anorexia, nausea, vomiting
Nursing interventions
Be aware of pt.at risk for K excess Assess pt.taking K+P.O. for GI upset Be aware that there are many forms of K+ supplements available. Check physicians order carefully
Assess and educate pt.concerning nutrition for adequate K+ intake
Hyperkalemia: serum value of >6 mEq/L
Etiology:
Pseudo hyperkalemia Excess K+ intake Renal excretion Drugs Shift of K+ out of cells
Clinical manifestations (hyperkalemia)
-ABD cramping, nausea, diarrhea -Lower extremities muscle weakness -Irritability -Paresthesias of face, tongue, feet and
hands -Flaccid muscle paralysis -Bradycardia, irregular heart rate, cardiac
standstill -ECG changes
Tall, peaked T waves, prolonged PR Widened QSR
Hyperkalemia: serum value of >6 mEq/L
Nursing Interventions
Monitor serum K+ report value >5.3 Caution hyperkalemia pts.to avoid foods high in K+ like:◦Chocolates, coffee, tea, dried fruits and
beans, meat and eggs, bananas Monitor for U/O Administer fresh blood as ordered Regulate IV w/ K+ carefully Utilized good phlebotomy techniques
CALCIUM :
8.5-10.5 mg/dl or 4.5-5.8 mEq/L
Functions:
• Formation of bone and teeth • Contraction of muscle, relaxation, activation
and excitation• Maintaining cardiac contraction• Cellular strength and permeability• Blood coagulation• Blocks sodium transport into the cell • Transmission of nerve impulses
Calcium ImbalancesEtiology
Hypocalcemia <4.5/9 mg/dl
Diet Chronic renal failure Mal absorption
syndromes Alcoholism Acute pancreatitis Loop diuretics Citrated blood alkalosis
Hypercalcemia >5.5/11 mg/dl
98%◦ Hyperparathyroidism◦ Thiazide diuretics ◦ malignancy
Immobility Vit.A & D overdose Ca cont. antacids Renal dysfunction Steroid acidosis
Clinical manifestations (hypocalcemia)
◦Irritability◦Decreased memory◦Delusions, hallucinations◦Hyperreflexia◦Parasthesias◦+ Chvostek’s sign◦+ Trousseau’s sign◦Laryngeal spasm, resp.arrest◦Tetany, seizures◦Abd’l. cramps◦ECG Prolonged QT interval
Nursing Interventions
Monitor serum Ca, VS, ECG Give PO Ca supp.30 mins.before eating
Be aware of safe administration of IV Ca
Teach clients to eat food high in Ca, Vit.D, protein
Take necessary precautions for confusion, seizure
Assess for prolong bleeding
Clinical manifestation (Hypercalcemia)
Headache, confusion Decreased memory Psychosis, stupor, coma Muscle weaknesses, fatigue Depressed reflexes Anorexia, N/V Bone pain, fractures Polyuria, dehydration Nephrolithiasis ( kidney stones) ECG
◦ Shortened QT interval
Nursing Interventions
Monitor serum Ca, VS, ECG Mobilization and wt. bearing activity Diet low in Ca
◦Dilute urine to prevent renal calculi formation
Hydrate w/ isotonic solutions Promote excretion w/loop diuretic Watch for digitalis toxicity
DEHYDRATION
defined as "the excessive loss of water and electrolytes from the body“
Dehydration can be caused by losing too much fluid, not drinking enough water or fluids, or both.
Dehydration: Definition
Infants and children are more susceptible to dehydration than adults because of their smaller body weights and higher turnover of water and electrolytes.
So are the elderly and those with illnesses
Dehydration: Definition
when losses are not replaced adequately, a deficit of water and electrolytes develop.
vomiting or diarrhea acute illness where there is loss of appetite and
vomiting Excessive urine output ex. diabetes or diuretic
use Excessive sweating (sports) Burns
Causes of Dehydration
Since diarrhea and vomiting are the most common causes of dehydration in children, the volume of fluid loss may vary from 5 ml/kg (normal) to 200 ml/kg
Concentration of electrolytes lost also varies NaCl and K are the most common
electrolytes lost through stools
History taking and do a thorough physical examination
classify type of dehydration depending on the amount of water and electrolytes lost
These are reflected by the signs and symptoms the child will present
Dehydration:Checking the main symptoms
Dehydration is classified as no dehydration, some dehydration, or severe dehydration based on how much of the body's fluid is lost or not replenished.
When severe, dehydration is a
life-threatening emergency
Dehydration: Classification
Clinical signs of dehydration
Look at condition
Eyes Tears
Mouth and tongue Thirst
Well , alert
NormalPresentMoistDrinks
normally, not thirsty
*restless,irritable
sunkenabsent
dry*thirsty,drink
s eagerly
*Lethargic or unconscious;flopp
yvery sunken & dry
absentvery dry
drinks poorly or not able to drink *
Feel skin pinch
Goes back quickly
*goes back slowly*
*Goes back very slowly
Decide
The patient has
no sign of dehydration
If the patient has 2 or more
signs, including at
least 1 *signs*, there
is Some Dehydration
If the patient has 2 or more signs, including at least 1 *sign* , there is
Severe Dehydration
TreatUse
treatment Plan A
Weigh the patient , if
possible and use
treatment Plan B
Weigh the patient and use treatment Plan C URGENTLY
Poor Skin Turgor
Three rules of home treatment:
1. give extra fluids2. continue feeding3. advise when to return to the
doctor
(if the child develops blood in the stool,
drinks poorly, becomes sicker, or is not better in three days).
WHO Treatment Plan A
ORS(ml)
the mother slowly gives the recommended amount of ORS by spoonfuls or sips
Note: If the child is breastfed, breast-feeding should continue.
After 4 hours, reassess and reclassify dehydration, and begin feeding to provide required amounts of potassium and glucose.
WHO Treatment Plan B
WHO Treatment Plan B
If there are no more signs of dehydration, do Plan A.
If there is still some dehydration, repeat
Plan B.
If the child now has severe dehydration, do Plan C.
WHO Treatment Plan C-Give IV infusion-If IV infusion is not possible, fluids should be given by nasogastric tube. -If none of these are possible and the child can drink, ORS must be given by mouth.
Note: In areas where cholera cannot be excluded for patients less than 2 years old with severe dehydration, antibiotics are recommended. Start Cotrimoxazole.
WHO Treatment Plan C
Normal saline does not correct acidosis or replace potassium losses, but can be used. Plain glucose or dextrose solutions are not acceptable for the treatment of severe dehydration.
REMEMBER:Do not give:
Very sweet tea, soft drinks, and sweetened fruit drinks.
(These are often hyperosmolar (high sugar content).
Can cause osmotic diarrhea, worsening dehydration and hyponatremia.
Also to be avoided are fluids with purgative action and stimulants (e.g., coffee, some medicinal teas or infusions).
Graded according to the signs and symptoms that reflect the amount of fluid lost.
There are usually no signs or symptoms in the early stages
As dehydration increases, signs and symptoms develop. Initially, thirst, restlessness, irritability, decreased skin turgor, sunken eyes and sunken fontanelles.
As more losses occur, these effects become more pronounced.
Assessment of Dehydration
Signs of hypovolemic shock (SEQUELAE)
1. diminished sensorium (lethargy)2. Lack of urine output3. Cool moist extremities4. A rapid and feeble pulse5. Decreased BP6. Peripheral cyanosis7. DEATH.
Summary of Management According to Degree of Dehydration
Degree ofDehydration
Amount of Fluid
Type of Fluid
Feeding
None Vol. per vol. replacement orafter each diarrhea stool: 50-100 ml (1/4-1/2 cup) if < 2yrs; 100-200 ml (1/2 -1 cup) if 2-10 yrs; ad libitum for older children
Suitable home fluids (not salty or highly sweetened), ORS, rice water, vegetable or chicken soup
Usual diet or formula, continue breastfeeding
Summary of Management According to Degree of Dehydration
Degree ofDehydration
Signs Fluids Feeding
Mild Slightly dry mucus mem- brane increased thirst, slightly reduced urine flow
ORS, 30-50 ml/kg in 4-6 hrs
Breastfeeding, full-strength cows milk or lactose-contg. formula, undil. lactose-free formula
Moderate Sunken eyes, sunken fontanelle, loss of skin turgor, dry mucus membrane
ORS, 60-90 ml/kg in 4-6 hrs
Same as above
Summary of Management According to Degree of Dehydration
Degree ofDehydration
Signs Fluids Feeding
Severe Signs of mod. dehydration plus one or more of ff: rapid, thready pulse, cyanosis, rapid breathing, delayed capillary refill time, lethargy, coma
IV fluids (Lactated Ringers or NSS),30ml/kg in 1/2 hr (1 hr for infants) then 70 ml/kg in 2 1/2 hrs for adult and 5 hrs for infants)
Begin after clinically improved and ORS has begun
IV TUBING
Calculating Administration Rates
One must know two key components before using the formula:Drop factor of the IV administration set
Amount of solution to be infused over one hour
Rate Calculations
Macrodrip Set10 drops = 1 ml15 drops = 1 ml20 drops = 1 ml
Microdrip Set60 drops = 1 ml
Blood Set10 drops = 1 ml
- Calibrated in drops per ml-this calibration is needed in calculating flow rates.
- Macrodrip set is used for routine adult IV administration, depending on the manufacturer and the type of tubing.
- 10/15, 15/60, 20/60, commonly drop factor.
- A macrodrip set is used when more exact measurements are needed, such as in pediatric units.
FORMULA
Drip Rate (gtts or mgtts/min) =
Total no. of ml x Drip Factor Total no. of min.
Total number of mlqtts/min= × drop factor
Total number of hours
1000ml = × 20gtts/ml
8hours
= 41-42gtts/min
Doctor’s Order: Start D5LR 1L to infuse over 8 hours the drop factor is 20qtts/ml,compute for the drops/minute.
Ex. gtts/min.Doctor’s order: Start 500ml of NS to
infuse over 300 minutes. The drop factor is 10 gtts/ml. compute for the gtts/min.?
Gtts/min = total no. of ml X drop factor
total no. of hour
= 500ml X 10gtts/ml
300mins.
= 16.66 gtts/min
Gtts/min = total no. of ml X drop factor
total no. of hour
= 500ml X 10gtts/ml 5 hours 60
= 16.66 gtts/min
Ex. gtts/min.Doctor’s order: Start 500ml of NS
to infuse over 300 minutes. The drop factor is 10 gtts/ml. compute for the gtts/min.?
FORMULA
ml per hour =
Total no. of mlTotal no of hours
total number of ml
Cc /hr=total number of hours
1000ml =
80ml/hour
= 12.5hour
Doctor’s Order: 1000ml of D5NM to infuse at a rate of 80cc/hour. A nurse determine that it will take, how many hours for 1L to infuse?
total number of ml
Cc/hour =c
total number of mlcc/hour=
total number of hour
1000cc =
10hours
= 100cc/hour
Start D5LR 1L to run for 10 hours. Compute for cc/hour?
Ex. Gtts/minD5NM 1L has been ordered by Dr. Dy for
his post-mastectomy patient to be infused at rate of 20gtts/minute. In how many hours will the said IVF last?
Gtts/min = _____total no. of ml_____ X drop factor total no. of hour
= __1,000ml__ X 15 20 gtts/min 60
= 15,000 1,200
= 12.5 hours
Other factors affecting Flow Rate:
1. Gauge of the catheter
2. Viscosity of the infusate
3. Height of the IV stand
4. Condition of the veins
5. Condition of the patient
COMPLICATIONS
Circulatory Overload can occur if an IV is not regulated and IV fluids infuse to rapidly for the patient’s body to handle.
Signs of fluid over load:
Tachycardia Increase Blood pressure Headache Anxiety Wheezing or signs of respiratory distress Diaphoresis Restlessness Distended neck veins Chest pain
- If an IV is running behind schedule-colaborate with the physician to determine the patients ability to tolerate an increased flow rate particularly patients with cardiac, pulmonary and renal problem.
A nurse should never arbitrarily speed up an IV to catch up if the IV is running behind the schedule.
Whenever an IV rate is increased the nurse should assess the patient for increased heart rate, increase respiration or lung congestion-indication of fluid overload.
AFTERCARE
Regulating IV fluids is an ongoing process from the time that an IV is started until it is completed. Hourly checks of an IV should include assessing the pt’s response to the IV, the rate of an IV flow, how much fluid has infused, how much fluid remains to be infused, and the condition of the IV insertion site. Adjust the rate if the IV is not flowing at the rate that was ordered.
If IV fluid is flowing in slowly, the nurse should check for a kink in the tubing or a position of problem. If an IV is flowing to rapidly, it may be leaking out around the IV insertion site. The whole system from the insertion site to the IV bag should be examined.
Thank you very much for listening
MAINTENANCE REQUIREMENTS HOLIDAY-SEGAR METHOD BODY SURFACE AREA METHOD
HOLIDAY-SEGAR METHOD
Estimates caloric expenditure in fixed weight categories
Assumption◦ 100 cal metabolized : 100 mL water
Not suitable for neonates < 14 days◦ Overestimates fluid needs
HOLIDAY-SEGAR METHOD
BODY WEIGHT
ml/kg/day ml/kg/hr Electrolytes
(mEq/100ml fluid)
First 10 kg 100 4 Na+ 3
Second 10 kg 50 2 Cl- 2
Each additional kg
20 1 K+ 2
EXAMPLE
What is the maintenance fluid rate for a an 8 year old child weighing 25 kg using the Holiday-Segar Method?
100 x 10 = 1000 ml+ 50 x 10 = 500 ml+ 20 x 5 = 100 ml 1600 ml/day
4 x 10 = 40 ml+ 2 x 10 = 20 ml+ 1 x 5 = 5 ml
65 ml/hr
EXERCISE
Using the Holiday-Segar Method, what is the full maintenance requirement and rate for a 10 year old patient who weighs 37 kg?
BODY SURFACE AREA METHOD Assumption: caloric expenditure
is related to BSA Not used in children < 10 kg
BSA METHOD
Component
Values
Water 1500 ml/m2/24 hrs
Na+ 30-50 mEq/m2/24 hrs
K+ 20-40 mEq/m2/24 hrs
STANDARD VALUES FOR USE IN BODY SURFACE AREA METHOD
BSA Formula
Surface area (m2) = ht (cm) x wt (kg)
3600
EXAMPLE
Using the BSA method, what is the maintenance requirement of an 8 year old who weighs 25 kg and is 132 cm tall?
BSA Formula
0.92 m2= 132 cm x 25 kg3600
Water = 1500ml/0.92/day= 1630 ml
Na+ = 40 mEq/0.92/day= 43.5 mEq
K+ = 30 mEq/0.92/day= 32.6 mEq
EXERCISE
Using the BSA Method, what is the maintenance requirement of a 12 year old boy who weighs 37 kg and is 142 cm tall?
DEFICIT THERAPY
Calculated Assessment Clinical Assessment
CALCULATED ASSESSMENT
Fluid deficit (L) = preillness weight (kg) – illness weight (kg)
% Dehydration = (preillness weight – illness weight)/preillness weight x 100%
CLINICAL ASSESSMENTDEHYDRATION MILD MODERATE SEVERE
Skin turgor Normal Tenting None
Skin touch Normal Dry Clammy
Buccal mucosa Moist Dry Parched/cracked
Eyes Normal Deep set Sunken
Tears Present Reduced None
Fontanelles Flat Soft Sunken
CNS Consolable Irritable Lethargic/obtunded
Pulse rate Normal Sl increased Increased
Pulse quality Normal Weak Peeble
Capillary refill Normal ~ 2 secs >3 secs
Urine output Normal Decreased anuric
FLUID REPLACEMENTMild (in 8 hours)
Moderate (1/4 in 2 hrs then ¾ in the next 6 hours)
Severe (1/3 in 2 hrs then 2/3 in the next 6 hours)
Infant/< 15 kg
50ml/kg 100 ml/kg
150 ml/kg
Older child/ > 15 kg
30 ml/kg 60 ml/kg 90 ml/kg
ICF & ECF COMPARTMENTS
Composition Intracellular (mEq/L)
Extracellular (mEq/L)
Na 20 133-145
K 150 3-5
Cl - 98-110
HCO3 10 20-25
PO4 110-115 5
CHON 75 10
ICF & ECF COMPARTMENTS
In dehydration, there are variable losses from the extracellular and intracellular compartments
Percentage of deficit is based on total duration of illness
BASIC MATH CONCEPTS
DECIMALS
All figures to the left of the decimal point are whole numbers
All figures to the right of the decimal point are decimal fractions
. 385 = . 3 8 5te
nth
s
thou
san
dth
s
hu
nd
red
ths
.385 = 385
1000
.38 = 38
100
.3 = 3
10
CHANGING FRACTIONS TO DECIMALS: Fractions can be changed to decimals by dividing the
numerator and the denominator
¾ = 3 ÷ 4 = 0.75
PERCENTAGE
Percentage ( % ) means hundredths Percent ( % ) is the same as a fraction with
denomination as 100.
3% = 3
100
45
10045% =
CHANGING PERCENT TO A DECIMAL & CHANGING DECIMAL TO PERCENT
To change percent to a decimal, remove the percent sign and divide the number by 100 or move the decimal point two places to the left.
4% = 4/100 = .04 or 0.04
To change a decimal to a percent, multiply by 100 or move the decimal point two places to the right and place % sign.
0.04 X 100 = 4% or 0.04 = 4%
RATIOA Ratio consists of two numbers as separated
by a colon ( : )
e.g. 1 : 4A ratio indicates that there is a relationship between the two numbers.A ratio is an indicated fraction.
e.g. ¼ = 1 : 4
The numbers in ratio must be expressed in the same terms.
e.g. 3 inches : 2 feet = 3 : 24(feet changes to
inches)
PROPORTION
It is a statement showing that the two ratios have equivalent values
1 : 50 = 2 : 100
If one value is not known, it can be solved by using the term X.
1 : X = 2 : 100 or 1 2
X 100~
means
extremes
THE METRIC SYSTEM
It is the international decimal system of weights and measures¤ In the metric system, fractions are expressed
as decimals¤ In the decimal system, the fraction ½ is
written as 0.5
METRIC SYSTEMLiter = vol. of fluids milli = one thousandths
Gram = weights of solids centi = one hundredthsMeter = measure of length deci = one tenth
mcg = one thousandths
RULE OF CONVERSION
When converting from a larger unit of measure to a smaller unit, multiply the larger unit by (1000, 100, 10) or move the decimal to the right.When converting a smaller unit of measure to a larger unit, divide the smaller unit by (1000, 100, 10) or move the decimal to the left.
e.g. 2.5 grams = ___________ mg.
APOTHECARIES SYSTEM
Grain (gr) Dram Ounce Minims Pounds
Approximate Equivalent Value:1 gr = 60 mg1 ml = 15 minims (16 minims)1 ounce= 30 ml1 ounce= 30 Gm1 kg = 2.2 pounds
e.g. 60 gr = _________ mg. 4 oz = _________ ml.
HOUSEHOLD MEASURES
1 teaspoon (tsp) = 4 – 5 ml1 Tablespoon (Tbsp) = 3 teaspoons (tsp)1 Tablespoon = 15 ml1 milliliter = 15 drops (gtts)
e.g. 5 ml = ______
CONVERSION OF TEMPERATURENormal Temperature = 37°C = 98°F
Conversion of Centigrade (Celsius) to Fahrenheit:
Conversion of Fahrenheit to Centigrade (Celsius):°C = 5 ( °F ) – 32
9
°F = 9 ( °C ) + 32
5
Interpretation of Doctor’s Order for Drugs
The nurse must understand the order perfectly before acting on it > The Drug > The Dose > The Route > The Frequency
If any of the above are unclear or open for interpretations, it is the Responsibility of the nurse to clarify the order with the physician.
Example:The order reads : Inderal 2 x4
a. What is the Drug?b. What is the Dose?c. What is the Route?d. What is the Frequency?e. Do
es this order need clarification?
The order reads : Lasix 10 mg IV 1 ml O.D. a. What is the Drug?b. What is the Dose?c. What is the Route?d. What is the Frequency?e. Does this order need clarification?
BASIC MATH CONCEPTS
DECIMALS
All figures to the left of the decimal point are whole numbersAll figures to the right of the decimal point are decimal fractions
. 385 = . 3 8 5
ten
ths
thou
san
dth
s
hu
nd
red
ths
.385 = 385
1000
.38 = 38
100
.3 = 3
10
CHANGING FRACTIONS TO DECIMALS: Fractions can be changed to decimals by dividing the
numerator and the denominator
¾ = 3 ÷ 4 = 0.75
PERCENTAGE
Percentage ( % ) means hundredths Percent ( % ) is the same as a fraction with
denomination as 100.
3% = 3
100
45
10045% =
CHANGING PERCENT TO A DECIMAL & CHANGING DECIMAL TO PERCENT
To change percent to a decimal, remove the percent sign and divide the number by 100 or move the decimal point two places to the left.
4% = 4/100 = .04 or 0.04
To change a decimal to a percent, multiply by 100 or move the decimal point two places to the right and place % sign.
0.04 X 100 = 4% or 0.04 = 4%
RATIOA Ratio consists of two numbers as separated
by a colon ( : )
e.g. 1 : 4A ratio indicates that there is a relationship between the two numbers.A ratio is an indicated fraction.
e.g. ¼ = 1 : 4
The numbers in ratio must be expressed in the same terms.
e.g. 3 inches : 2 feet = 3 : 24(feet changes to
inches)
PROPORTION
It is a statement showing that the two ratios have equivalent values
1 : 50 = 2 : 100
If one value is not known, it can be solved by using the term X.
1 : X = 2 : 100 or 1 2
X 100~
means
extremes
THE METRIC SYSTEM
It is the international decimal system of weights and measures
¤ In the metric system, fractions are expressed as decimals
¤ In the decimal system, the fraction ½ is written as 0.5
METRIC SYSTEMLiter = vol. of fluids milli = one
thousandthsGram = weights of solids centi = one hundredths
Meter = measure of length deci = one tenthmcg = one thousandths
RULE OF CONVERSION
When converting from a larger unit of measure to a smaller unit, multiply the larger unit by (1000, 100, 10) or move the decimal to the right.
When converting a smaller unit of measure to a larger unit, divide the smaller unit by (1000, 100, 10) or move the decimal to the left.
e.g. 2.5 grams = ___________ mg.
APOTHECARIES SYSTEM
Grain (gr) Dram Ounce Minims Pounds
Approximate Equivalent Value:1 gr = 60 mg1 ml = 15 minims (16 minims)1 ounce= 30 ml1 ounce= 30 Gm1 kg = 2.2 pounds
e.g. 60 gr = _________ mg. 4 oz = _________ ml.
HOUSEHOLD MEASURES
1 teaspoon (tsp) = 4 – 5 ml1 Tablespoon (Tbsp) = 3 teaspoons (tsp)1 Tablespoon = 15 ml1 milliliter = 15 drops (gtts)
e.g. 5 ml = ______
CONVERSION OF TEMPERATURENormal Temperature = 37°C = 98°F
Conversion of Centigrade (Celsius) to Fahrenheit:
Conversion of Fahrenheit to Centigrade (Celsius):°C = 5 ( °F ) – 32
9
°F = 9 ( °C ) + 32
5
Interpretation of Doctor’s Order for Drugs
The nurse must understand the order perfectly before acting on it > The Drug > The Dose > The Route > The Frequency
If any of the above are unclear or open for interpretations, it is the Responsibility of the nurse to clarify the order with the physician.
Example:The order reads : Inderal 2 x4
a. What is the Drug?b. What is the Dose?c. What is the Route?d. What is the Frequency?e. Does this order need clarification?
The order reads : Lasix 10 mg IV 1 ml O.D. a. What is the Drug?b. What is the Dose?c. What is the Route?d. What is the Frequency?e. Does this order need clarification?
GENERAL FORMULA FOR DRUG CALCULATION
1. D x QS
2. Calculation by Ratio : Proportion
8 mg : x = 16 mg : 1 tab
(works for any computation of Dosage if you have a given and a need to determine the unknown).
Rule : 1. Units for each ratio must be the same.2. Units for each ratio must be placed in the same
order.
Computation of Dosages:
When the dose prescribed is in milligram (mg) and the dose available is in Gram (Gm) or vice versa.
E.g. The order reads : 0.008 Gm of Morphine Sulfate IV q 4 hours prn for pain. Ampule available is labeled 10 mg/ml.
1. What do you know?0.008 Gm - 8 mg10 mg/ml -
2. What do you need to know? Knownamount in cc for 0.008 Gm dose
3. Setting up the proportion:a. the units for each ratio must be placed in the
same orderb. the units for each ratio must be the same
( mg to mg ) 8mg : X = 10 mg : ml
4. solve for the correct dosage
8 mg : X = 10 mg : ml
10 mg X = 8 mg/ml
X = 8 mg/ml 10 mg
X = .8 ml
When the dose is ordered in one system and the dose on hand is in another system.
E.g. The order reads : codeine sulfate ¼ gr P.O. q 8 hrs PRN for pain. Tablets on hand are labeled 0.015 Gm tablets.
1. What do you know? Known¼ gr 1 gr = 60 mg0.015 Gm / tab 1 Gm =
1000 mg¼ = .25
2. What do you need to know?
# of tablets for ¼ gr dose
3. Setting up the proportiona. the units for each ratio must be
the sameb. the units for each ratio must be
placed in the same order.
.25 gm : X = 0.015 gm : 1 tab
15 mg : x = 15 mg : 1 tab
4. Solve for the correct dosage:
15 mg : x = 15 mg : 1 tab
15 mg x = 15 mg / tab
x = 15 mg / tab 15 mg x = 1 tab
Computation of Correct Insulin Dosage U - 40 means U - 80 means U - 100 means
Insulin syringes are calibrated according to the strength of insulin with which it is to be used.
U 40 insulin needs a U 40 syringe
U 80 insulin needs a U 80 syringe
If this can not be done, the dose can be converted to milliliters
Dose RequiredDose on Hand X 1 ml = ml needed
• Serious error can occur if incorrect syringe or incorrect b calculations are used
• It is essential that all insulin be checked by a second RN to confirm that errors in dosage are not made and error in the type of insulin were not made.
Fractional Dosages in Infants and Children
Children’s Doses Clarks’ Rule:
weight of child in pounds X A.D. = child’s dose
150
Body Surface Area e.g. Wt = 10 kgBSA X A.D. = child’s dose 1.7
BSA = 4(wt in kg) + 7 = BSA in m²wt in kg + 90
= 4(10 kg) + 7 = 47 10+ 90
= .47 m²
Child’s dose = .47 m² X 500 1.7
Youngs’ Formula:
Age of child in Years X A.D. = Child’s dose
Age of child + 12
CALCULATION OF FLUID VOLUME(BASED ON BODY WEIGHT)
1. WEIGHT --- 1 – 10 kg. --- 100ml/kg.Eg. Wt = 8 kg. --- 800cc
2. WEIGHT --- 11 – 20 kg.--- 1,000+50ml/excess b.wt.Eg. Wt = 15 kg. 1,000=250ml = 1,250ml
15 50 -10 X 5 5 250
3. WEIGHT > 20 kg.Eg. Wt = 27 kg. 1,500 + 20 ml/excess b.wt.
1,500 + 140 ml = 1640 ml.27 20
-20 X 7 7 140
Calculation of IV Flow Rates
Calculation of cc/hr is essential in most IV therapy.
Volume # of hrs
E.g. 1 L over 8 hrs = 125 cc/hr
50 cc over 20 minutes = 150 cc/hr
= cc/hr
Calculation of gtt/min (Long Method)
STEPS : 1. Need to know cc/hr to calculate
2. Gtt factor = gtt / mlgtt factors : macrodrip 10, 15, 20 gtts/ml
microdrip 60 gtt/ml
EXAMPLE : LONG METHODDoctors Order : Run 1L D5W over 8 hours
Microdrip - 1000 ml ÷ 8 hours = 125 cc/hr
125 cc x 60 gtt/ml = 125 gtt/ml 60 min 1
10 gtt/ml set 125cc x 10 gtt/ml = 20 – 21 gtt/min 60 min 1
15 gtt/ml set 125cc x 15 gtt/ml = 31 gtt/min 60 min 1
20 gtt/ml set 125 cc x 20 gtt/ml = 41 – 42 gtt/min 60 min 1
SHORT METHOD
cc / hr ÷ 6 for 10 gtt / min
cc / hr ÷ 4 for 15 gtt / min
cc / hr ÷ 3 for 20 gtt / min
cc / hr = gtt / min for microdrip set
Sources Fluids & Electrolytes, Lippincott Williams &
Wilkins Fluids & Electrolytes, Walters Kluwer Nelson’s Texbook of Pediatrics WHO department of child and adolescent
development (Medline Plus)http://www.nlm.nih.gov/MEDLINEPLUS/ency/article/000982.htm