fluid & electrolytes acid base imbalances chapter 17
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Megan McClintock Winter 2012. Fluid & Electrolytes Acid Base Imbalances Chapter 17. Maintained by the intake and output of water and electrolytes and regulation by the renal and pulmonary systems - PowerPoint PPT PresentationTRANSCRIPT
FLUID & ELECTROLYTESACID BASE IMBALANCES
CHAPTER 17
Megan McClintockWinter 2012
HOMEOSTASIS Maintained by the intake and output of water
and electrolytes and regulation by the renal and pulmonary systems
Acid-base balance is necessary for many physiologic processes (respiration, metabolism, function of the CNS)
Many disease and treatments affect this balance
WATER More important to life than any other
nutrient 60% of an adult’s body weight, more in
a child, less in the elderly Found in foods (but not in alcohol) Daily need is about 2000 mL 1 liter of water weighs 1 kg
URINE SPECIFIC GRAVITY
Measures the kidney’s ability to concentrate or dilute urine
1.002 – 1.028 High is dehydrated Low is overhydrated (or unable to
concentrate) Kidney failure often causes a fixed specific
gravity
ELECTROLYTES Cations (positively charged)
K+, Na+, Ca+, Mg+ Transmit nerve impulses to muscles and
contract skeletal and smooth muscles Anions (negatively charged)
Attached to cations Cl-, HCO3-, PO4-, SO4-
Are always kept in balance
DISTRIBUTION OF BODY FLUIDS & ELECTROLYTES
Intracellular (2/3) – K+, PO4- Extracellular (1/3) – Na+, Cl-
Interstitial (lymph) Intravascular (blood plasma) Transcellular (cerebrospinal, pleural,
peritoneal, synovial fluids)
REGULATION OF FLUID & ELECTROLYTE MOVEMENT
OSMOLALITY Indicates the water balance of the body Serum osmolality (275 - 295)
High is water deficit Low is water excess
Urine osmolality (100-1300) High is concentrated Low is dilute
FLUID SPACING First spacing
Normal Second spacing
Edema Third spacing
Ascites Burn edema
REGULATION OF WATER BALANCE Hypothalmic Regulation
Thirst is stimulated ADH (vasopressin) release is stimulated
Pituitary Regulation ADH (vasopressin) is released
Adrenal Cortical Regulation Glucocorticoids & mineralocorticoids are released
Renal Regulation Adjust urine volume and electrolyte excretion Normal is 1.5 Liters of urine/day
REGULATION OF WATER BALANCE (CONT.) Cardiac Regulation
ANP & BNP will stop the action of the adrenal cortex and the kidney
GI Regulation Intake and output are reabsorbed here Diarrhea and vomiting can lead to significant
losses Insensible Water Loss
600-900 mL/day from the lungs and skin Increases with fever, exercise
GERONTOLOGIC CONSIDERATIONS Structural changes in the kidney and decreased
renal blood flow Decreased GFR Decreased creatinine clearance Loss of ability to concentrate urine and thus conserve
water Decrease in renin and aldosterone Increase in ADH and ANP
Loss of subcutaneous tissue Decrease in thirst mechanism Musculoskeletal changes Mental status changes Incontinence
FLUID VOLUME DEFICIT
What causes it?
What can you do?
FLUID VOLUME EXCESS
What causes it?
What can you do?
NURSING INTERVENTIONS Strict I/O
Intake – oral, IV, tube feedings, retained irrigants Output – urine, excess sweating, wound/tube
drainage, vomitus, diarrhea Urine specific gravity Assessment of CV, Resp, Neuro, Skin status Daily weight under standardized conditions Don’t “catch up” IV fluids No water with NG suction, use isotonic saline Keep fluids accessible and within reach Give warm or cold fluids (not room temperature)
SERUM ELECTROLYTES Sodium (Na) 135 - 145
Primarily responsible for maintaining osmotic pressure (intracellular and extracellular fluids)
Increased with fluid deficit Decreased with fluid excess
Potassium (K) 3.5 – 5.0 Major component of cardiac function Increased with poor kidney function Decreased with excessive urination, diarrhea or vomiting
Chloride (Cl) 96 – 106 Works with Na to maintain osmotic pressure Increased with poor kidney function Decreased with excessive vomiting or diarrhea
Calcium (Ca) 8.6 – 10.2 Transmission of nerve impulses, heart and muscle
contractions, blood clotting, formation of teeth and bone Phosphate (PO4) 2.4 – 4.4
Function of muscle, RBCs, and the nervous system
THE MAGIC FOURS
Electrolyte Range Magic 4Potassium 3.5 - 5.0 4Chloride 96 - 106 104Sodium 135 - 145 140pH 7.35 - 7.45 7.4CO2 35 - 45 40HCO3 22 - 26 24
Hematocrit normal is 3 times the hemoglobin
SODIUM (135 - 145) Major cation of ECF Primary determinant of osmolality GI tract absorbs sodium from food Regulated by kidneys, ADH,
aldosterone Sodium level reflects the ratio of
sodium to water Imbalances are typically associated
with fluid volume problems
HYPERNATREMIA (HIGH SODIUM)
What can you do?
What causes it?
HYPONATREMIA (LOW SODIUM)
What causes it?
What can you do?
POTASSIUM (3.5 - 5.0) Major cation of ICF Sodium-potassium pump requires
magnesium Moves into cells during formation of
new tissues and leaves the cell during tissue breakdown
Diet is the source of potassium Kidneys are primary route of loss
HYPERKALEMIA (HIGH POTASSIUM)
What can you do?
What causes it?
HYPOKALEMIA (LOW POTASSIUM)
What causes it?
What can you do?
CALCIUM (8.6 – 10.2) Primary source is bones Regulated by parathyroid hormone,
calcitonin, and vitamin D Affects transmission of nerve impulses,
heart and muscle contractions, blood clotting, and forming of teeth and bone
HYPERCALCEMIA (HIGH CALCIUM)
What can you do?
What causes it?
What are the
symptoms?
HYP0CALCEMIA (LOW CALCIUM)
PHOSPHATE IMBALANCES Hyperphosphatemia
Cause - renal failure S/S – calcium deposits in joints, skin, kidneys, eyes;
hypocalcemia, tetany, neuromuscular irritability Tx – decrease intake of dairy products, good hydration, fix
hypocalcemia Hypophosphatemia
Cause – malnutrition, malabsorption syndrome, alcohol withdrawal
S/S – CNS depression, confusion, muscle weakness, dysrhythmias
Tx – oral supplements (Neutra-Phos), lots of dairy products, IV phosphate (but this can cause sudden hypocalcemia)
MAGNESIUM IMBALANCES Hypermagnesemia
Cause – increased intake (ie. MOM, Maalox) with chronic kidney disease
S/S – lethargy, n/v, loss of DTRs, can have respiratory and cardiac arrest
Tx – avoid magnesium-containing drugs, IV calcium, increased fluid intake, may need dialysis
Hypomagnesemia Cause – prolonged fasting or starvation, chronic alcoholism,
diuretics S/S – confusion, hyperactive DTRs, tremors, seizures, cardiac
dysrhythmias Tx – oral supplements, increase green veggies, nuts, bananas,
oranges, peanut butter, chocolate; IV or IM magnesium (if given too rapidly can cause cardiac or respiratory arrest)
MEDICATIONS Loop diuretics Thiazide diuretics Potassium sparing diuretics Electrolytes Kayexolate
ACID BASE BALANCE
REGULATION OF ACID-BASE BALANCE Buffer system (immediate)
Primary regulator Won’t work without good functioning
respiratory and renal symptoms Respiratory system (minutes, max in
hours) Excretes CO2 and water
Renal system (2-3 days to max respond) Reabsorbs HCO3
ARTERIAL BLOOD GAS pH (7.35 – 7.45) CO2 (35 – 45) HCO3 (22 – 26) Base excess (+2 to -2)
If high, metabolic alkalosis If low, metabolic acidosis
DETERMINING ACID–BASE BALANCE
1. Is pH acid, base or normal?2. Is CO2 acid, base or normal? 3. Is HCO3 acid, base or normal?4. Which of the components match?5. Is there compensation?
Is non-matching reading abnormal? – partial compensationIs non-matching reading normal? – no compensation
RESPIRATORY ALKALOSIS
RESPIRATORY ALKALOSIS Causes
Hyperventilation Pulmonary disease High altitudes
Signs/symptoms Hyperventilation Feels “light-headed” Arrhythmias Anxiety
Treatment Breathe into paper bag Rebreather mask Anti-anxiety medicine Relaxation techniques Reduce stimulation Treat pain/fever Assess:
Resp rate/depth HR & BP Serum K levels Hydration status Check for digitalis toxicity
RESPIRATORY ACIDOSIS
RESPIRATORY ACIDOSIS Causes
CNS depression Loss of lung surface Neuromuscular disease Immobility Mechanical ventilation
Signs/symptoms Dyspnea Hypoxia Drowsiness Tachycardia Seizures Diaphoresis
Treatment Turn, cough, deep breathe Semi-Fowler’s position Suction Incentive spirometer Seizure precautions Decrease use of sedatives Bronchodilators May need ventilator Assess:
Resp rate/depth HR & BP Patiency of airway
METABOLIC ALKALOSIS
METABOLIC ALKALOSIS Causes
NG suctioning Prolonged vomiting Diuretic use Multiple blood transfusions CPR (given bicarb)
Signs/symptoms Dizziness Dysrhythmias Convulsions Confusion Muscle cramps (late sign)
Treatment Identify and treat the cause! IV fluids Stop giving bicarbonate Give antiemetics Give Diamox Assess:
Resp rate/depth HR & BP Serum K levels (usually low) Hydration status (tend to be
dehydrated) Check for digitalis toxicity Parasthesias
METABOLIC ACIDOSIS
METABOLIC ACIDOSIS Causes
Diabetic ketoacidosis Renal or liver failure Severe diarrhea Vomiting Starvation
Signs/symptoms Kussmaul respirations Hypotension Arrythmias Warm to hot ,flushed skin Confusion
Treatment Identify and treat the
cause! Administer insulin (if due to
ketoacidosis) Give antiemetics IV fluids IV bicarbonate Assess:
Renal function (BUN, creatinine)
Serum K levels (tends to go up but down once insulin given)
Hydration status
IV FLUIDS Isotonic
NS D5W LR
Hypertonic 3% NS D51/2NS D10W
Hypotonic 1/2NS
Plasma Expanders
CENTRAL VENOUS ACCESS DEVICES Centrally inserted
catheters (CVCs)
Peripherally inserted central catheters (PICCs)
Implanted infusion ports
NURSING CARE OF CVADS Inspect site for redness, edema, warmth, drainage, pain Dressing change/cleaning with sterile technique using
chlorhexidine (back and forth scrub to generate friction) Maintain transparent dressing c/d/I Change injection caps using sterile technique Teach pt to turn head away from insertion site during
cleaning and cap change Have patient Valsalva during cap change if unable to
clamp Use push-pause method to flush (creates turbulence) Removal of non-tunneled CVCs and PICCs may be done
by a trained nurse (have pt Valsalva as last of catheter is withdrawn, apply pressure immediately, inspect catheter tip)