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Ch-39 Lecture - Bhbhbh.
Miami Dade College
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Chapter 39 Lecture
Fluid, Electrolyte, and Acid-Base Balance
Fluids and electrolytes are vital to life; adequate balance is imperative to maintain healthy functioning of the body. Fluids and electrolytes are involved in almost every cellular reaction and function. Chemical reactions that occur in the body depend on a careful acid and base balance.
Body Fluids
The main body fluid is water, making up 50-60% of body weight in a healthy person. We can survive for several days without food but only a few days without water. Water in the body functions primarily to: - Transport nutrients to cells and wastes from cells - Transport hormones, enzymes, blood platelets, and red and white blood cells - Facilitate cellular metabolism and proper cellular chemical functioning - Act as a solvent for electrolytes and nonelectrolytes - Help maintain normal body temperature - Facilitate digestion and promote elimination - Act as a tissue lubricant
BODY FLUID COMPARTMENTS
Body fluid is located in two compartments: - Intracellular fluid (ICF) – fluid within the cells; ICF is about 70% of total body water or 40% of body weight - Extracellular fluid (ECF) – all the fluid outside the cells; ECF is about 30% of total body water or 20% of body weight; includes two major areas and a minor area: o Intravascular fluid – plasma, liquid component of blood o Interstitial fluid – fluid that surrounds tissue cells and includes lymph o Transcellular fluid – includes cerebrospinal, pericardial, synovial, intraocular, and pleural fluids as well as sweat and digestive secretions
VARIATIONS IN FLUID CONTENT
Age o Infants have considerably more total body fluid and ECF than adults; ECF is more easily lost from the body so this makes infants more prone to fluid volume deficits o Older adults have more fat cells and less muscle so it results in less body fluid; this puts them at risk for fluid imbalance
Body fat
o Fat cells contain very little water, so obese people have a lower percentage of total body water
- Gender o Women have more body fat than men, so they have less body fluid
FLUID BALANCE
Our bodies obtain water from ingesting liquids and food, and as a byproduct of metabolism. Ingesting liquids is our main source.
Fluid intake is regulated by the thirst control center located in the hypothalamus, which is triggered by intracellular dehydration and decreased blood volume.
Generally, fluid intake averages 2,600 mL/day, with approximately 1,300 mL coming from ingested water, 1,000 mL coming from ingested food, and 300 mL from metabolic oxidation.
Sensible loss – loss that can be measured; fluid lost during urination, defecation, and wounds
Insensible loss – loss that cannot be measured or seen; fluid lost from sweating and breathing
Fluid output averages 2,500 mL to 2,900 mL per day with approximately 1,500 mL from kidneys, 600 mL from the skin, 300 mL from the lungs, and 200 mL in the feces.
Output should equal input
Electrolytes
Electrolytes are substances that are capable of breaking into particles called ions (electrically charged atom).
Cations are positively charged ions. The major cations in the body fluid are sodium, potassium, calcium, hydrogen, and magnesium.
Anions are negatively charged ions. The major anions in the body fluid are chloride, bicarbonate, and phosphate.
Major electrolytes in ECF include sodium, chloride, calcium, and bicarbonate.
Major electrolytes in ICF include potassium, phosphorus, and magnesium.
Pituitary glad o Stores and releases the antidiuretic hormone (ADH) which acts to allow the body to retain water
Thyroid gland o Increases blood flow in the body by releasing thyroxine, leading to increased renal circulation and resulting in increased glomerular filtration and urinary output
Nervous system o Inhibits and stimulates mechanisms influencing fluid balance; acts chiefly to regulate sodium and water intake and excretion o Regulates oral intake by sensing intracellular dehydration, which trigger thirst o Neurons, called osmoreceptors, are sensitive to changes in the concentration of ECF, sending appropriate impulses to the pituitary gland to release ADH or inhibit its release to maintain ECF volume concentration
Gastrointestinal tract o Absorbs water and nutrients that enter the body through this route
Parathyroid glands o Regulate calcium and phosphate balance by means of parathyroid hormone (PTH); PTH influences bone reabsorption, calcium absorption from the intestines, and calcium reabsorption from the renal tubules
OSMOSIS
Osmosis is the major method of transporting body fluids. Through the process of osmosis, water (the solvent) passes from an area of lesser solute concentration and more water, to an area of greater solute concentration and less water until equilibrium is established.
Osmolarity – the concentration of particles in a solution
- Isotonic – a solution with the same osmolarity as plasma
- Hypertonic – a solution with a higher osmolarity than plasma
- Hypotonic – a solution with a lower osmolarity than plasma
DIFFUSION
Diffusion is the tendency of solutes to move freely throughout a solvent.
Oxygen and carbon dioxide exchange in the alveoli and capillaries occurs by diffusion.
ACTIVE TRANSPORT
Active transport is a process that requires energy for the movement of substances through a cell membrane, against the concentration gradient, from an area of lesser solute concentration to an area of higher solute concentration.
Requires ATP for energy, which is stored in all cells.
CAPILLARY FILTRATION
Filtration is the passage of fluid through a permeable membrane. Capillary filtration results from the force of blood “pushing” against the walls of the capillaries.
Pressure inside arterioles is a positive pressure which pushes fluid out; pressure inside a venule is a negative pressure which pulls fluid in
Acid-Base Balance
Body fluids must maintain an acid-base balance to sustain health, homeostasis, and life. Conditions such as infection or trauma can alter the acid-base balance.
Acid – a substance containing hydrogen that can be liberated or released
Base – a substance that can accept or trap hydrogen
pH – the unit of measure used to describe acid-base balance; an expression of hydrogen ion concentration
pH scale ranges from 1 to 14. The lower the number, the more acidic the substance is. The higher the number, the more alkaline the substance is. Gastric secretions have a pH of approximately 1-1, where as pancreatic secretions have a pH of approximately 10.
Normal blood plasma is slightly alkaline – pH of 7 to 7.
Acidosis – excess of hydrogen ions or loss of base ions in ECF; pH falls below 7.
Those at especially at risk for a fluid volume deficit include young children, older, adults, and people who are ill.
A third-space fluid shift occurs when ECF is shifted to transcellular compartments such as the pleural, peritoneal (ascites), or pericardial areas; joint cavities; the bowel; or an excess accumulation of fluid in the interstitial space.
Once third-spacing occurs, the fluid can’t be exchanged with the ECF, and the end result is a fluid volume deficit even though the fluid hasn’t been lost from the body.
Some causes of third-spacing include a severe burn, a bowel obstruction, surgical procedures, pancreatitis, ascites, or sepsis.
FLUID VOLUME EXCESS
FVE is excessive retention of water and sodium in ECF; also known as hypervolemia.
Common causes include malfunction of the kidneys and failure of the heart to function as a pump.
An increase of sodium in the ECF causes fluid to be pulled from the cells to equalize the tonicity. The accumulation of this fluid is known as edema.
Page 1482 shows grading scale for edema
Electrolyte Imbalances
Abnormalities in electrolyte levels can indicate:
- fluid imbalance
- acid-base imbalance
- neuromuscular dysfunction
- cardiac dysfunction
- renal endocrine dysfunction
- skeletal dysfunction
SODIUM
Most abundant ECF electrolyte
Hyponatremia – deficit of sodium; <135 mEq/L
Possible causes: vomiting, diarrhea, fistulas, sweating, use of diuretics
S/S: confusion, hypotension, edema, muscle cramps and weakness, dry skin
Cerebral edema can lead to seizures
Permanent neurologic damage and death can result from severe hyponatremia
Hypernatremia – surplus of sodium; >145 mEq/L
Possible causes: fluid deprivation, lack of fluid consumption, diarrhea, excess insensible water loss
CNS especially affected resulting in signs of neurologic impairment including: restlessness, weakness, disorientation, delusion, hallucinations
Permanent brain damage, especially in children, can occur POTASSIUM
Most abundant ICF electrolyte
Hypokalemia – deficit of potassium; <3 mEq/L
Possible causes: vomiting, gastric suction, alkalosis, diarrhea, use of diuretics
S/S: muscle weakness and leg cramps, fatigue, paresthesias, dysrhythmias
Hyperkalemia – surplus of potassium; >5 mEq/L
Possible causes: renal failure, hypoaldosteronism, use of certain meds (potassium chloride, heparin, ACE inhibitors, NSAIDs, potassium-sparing diuretics)
Occurs less often than hypokalemia but is much more dangerous
Nerve conduction and muscle contractility can be affected.
Skeletal muscle weakness and paralysis may occur.
Cardiac irregularities, including cardiac arrest if not corrected
CALCIUM
Hypocalcemia – deficit of calcium; <8 mg/dL
Possible causes: inadequate calcium intake, impaired calcium absorption, excessive calcium loss
S/S: numbness and tingling of fingers, mouth, or feet; tetany; muscle cramps; seizures
Hypercalcemia – surplus of calcium; >10 mg/dL
Hyperchloremia – surplus of chloride; >106 mEq/L
Possible causes: metabolic acidosis, head trauma, increased perspiration, excess adrenocortical hormone production, decreased glomerular filtration
S/S: tachypnea, weakness, lethargy, diminished cognitive ability, HTN, decreased cardiac output, dysrhythmias, coma
THE NURSING PROCESS FOR FLUID, ELECTROLYTE, AND ACID-BASE BALANCE
Assessing
The nursing assessment is directed toward the following:
- Identifying patients at high risk for fluid, electrolyte, and acid-base imbalances
- Determining specific imbalances by identifying the nature of the imbalances to include their severity, etiology, and defining characteristics or assessment findings
- Determining the plan of care, including the appropriate nursing diagnoses or collaborative problems, followed by the identification of specific outcomes and associated interventions
- Evaluating the effectiveness of the plan of care
NURSING HISTORY
Ask patient if they have any of the following risk factors:
- acute and chronic illnesses (diabetes, CHF, renal failure)
- abnormal losses of body fluids (prolonged or severe vomiting or diarrhea, draining wounds, fistulas)
- burns
- trauma
- surgery
- therapies that may disrupt fluid and electrolyte balance (meds like diuretics and steroids, IV therapy, TPN)
You can also ask:
Describe the amount and types of fluid you usually drink in a 24-hour period. Have there been any recent changes?
Describe your usual voiding/urination habits. Have there been any recent changes? Are you losing fluids in any other way?
Do you think have been dehydrated or overhydrated lately?
Have you been trying to lose weight by dieting, using diuretics, laxatives, or diet aids?
PHYSICAL ASSESSMENT
Assess the following (refer to Table 39-4 on pages 1485-1486 for detailed information):
- Skin turgor
- Tongue turgor
- Moisture and oral cavity
- Tearing and salivation
- Appearance of skin and skin temperature
- Facial appearance
- Edema
- Body temperature
- Pulse
- Respirations
- BP
FLUID INTAKE AND OUTPUT
DAILY WEIGHTS
Weigh the patient at the same time every day, with the same amount of clothes on, and with the same scale if possible
LABS
CBC
Looking at RBCs and H&H. Significant values include:
- increased hct values: found in severe fluid volume deficit and shock
- decreased hct values: found with acute, massive blood loss, and with hemolytic reaction after transfusion of incompatible blood or with fluid overload
- increased levels of hgb: found in hemoconcentration of the blood
- decreased levels of hgb: found with anemia states, severe hemorrhage, and after a hemolytic reaction
Serum Electrolytes, Blood Urea Nitrogen, and Creatinine Levels
S - Students - Sodium P - Please - Potassium C - Clean - Calcium M - My - Magnesium
Decreased urine specific gravity can occur with:
- renal damage
Arterial Blood Gases (ABGs)
HANDOUTS
Diagnosing
Fluid, electrolyte, and acid-base disturbances as the problem:
- Excess Fluid Volume
- Deficient Fluid Volume
- Risk for Deficient Fluid Volume
- Risk for Imbalanced Fluid Volume
Fluid, electrolyte, and acid-base disturbances as the etiology:
- Ineffective Breathing Pattern r/t compensatory mechanism by lungs (hypoventilation or hyperventilation)
- Anxiety r/t hyperventilation
- Risk for Injury r/t neuromuscular irritability, cardiac arrhythmia
- Impaired Oral Mucous Membrane r/t fluid volume deficit
- Risk for Impaired Skin Integrity r/t fluid volume deficit or fluid volume overload
- Disturbed Thought Processes r/t cerebral edema, mental confusion or disorientation, or convulsions
Planning
Your plan should focus on making sure the healthy adult patient will:
- maintain an approximate balance between fluid intake and fluid output
- maintain a urine specific gravity within normal range
- practice self-care behaviors to promote fluid, electrolyte, and acid-base balance; maintain adequate intake of fluid and electrolytes; respond
appropriately to the body’s signals of impending fluid, electrolyte, or acid—base imbalance
When an imbalance exists, the patient will:
- relate relief of symptoms after implementation of treatment regimen
- exhibit s/s of restored balance or homeostasis after initiation of treatment
- identify s/s of recurrence of imbalance with need to notify the primary health care provider
Implementing
PREVENTING FLUID AND ELECTROLYTE IMBALANCES
- Be familiar with common life events that can lead to fluid imbalances, and observe patient carefully (i. infants have a higher percentage of body water so they are at a greater risk of fluid imbalances)
- Note the patient’s present fluid and food intake, and obtain a history of the patient’s previous eating and drinking patterns. Have they been on a fad diet?
- Note whether the patient experiences excessive thirst or little to no thirst.
- Be aware of and attempt to prevent possible fluid loss (i. vomiting, pronounced perspiration, diarrhea, draining wound, excessive urinary output)
- Consider ways in which the patient’s medical regimen may lead to fluid and electrolyte imbalances (i. use of diuretics)
- Learn whether the patient has been self-administering a treatment that may threaten fluid balance (enemas, laxatives, antacids, OTC or herbal meds to promote urination)
- Consider conditions with destructive effects on the body as threats to fluid balance (i. immobilization, trauma, burns, surgical procedures, exposure to toxic agents)
- Teach patients to observe for s/s of fluid imbalances and to report them promptly (i. rapid weight loss or gain; swollen fingers, feet, and ankles; puffy eyelids; muscle weakness; change in skin sensations; scanty or profuse urine production)
- Help patients and families understand the significance of maintaining fluid balance and preventing imbalances
- Be aware that normal physiologic changes associated with aging affect older patients’ ability to maintain fluid balance
DEVELOPING A DIETARY PLAN
Help the patient plan a diet that will help resolve fluid or electrolyte imbalance, such as:
- accurate administration of the medications
- understand the intended therapeutic effect and evaluate the effectiveness of the therapy through patient assessment
- assess for adverse effects
- understand and appreciate the risks associated with administration and the appropriate precautions to avoid adverse outcomes
- assess for drug interactions
- teach patients about the medications
Diuretics
Drugs that increase renal excretion of water, sodium, and other electrolytes
They increase the risk for fluid volume deficit and serious electrolyte deficiencies
Carefully monitor fluid intake, urine output, and serum electrolytes; with special monitoring of potassium
ADMINISTERING IV THERAPY
Isotonic – total osmolality close to that of the ECF; replace ECF
- 5% dextrose in water (D 5 W) o supplies about 170 cal/L and free water (contains 50 g of glucose) o used in fluid loss, dehydration, hypernatremia o should not be used in excessive volumes because it does not contain any sodium; thus the fluid dilutes the amount of sodium in the serum; brain swelling, or hyponatremic encephalopathy, can develop rapidly and cause death unless it is promptly recognized and treated
- 0% NaCl (normal saline) o not desirable as routine maintenance solution because it provides only Na+ and Cl-, which are provided in excessive amounts o may be used to expand temporarily the extracellular compartment if circulatory insufficiency is a problem; also used to treat hypovolemia, metabolic alkalosis, hyponatremia, hypochloremia o used with administration of blood transfusions
- Lactated Ringer’s solution o contains multiple electrolytes in about the same concentrations as found in plasma o used in the treatment of hypovolemia, burns, and fluid lost from gastrointestinal sources o useful in treating metabolic acidosis
Hypotonic – hypotonic to plasma; replace ICF
- 0% NaCl (1/2 NS) o a hypotonic solution that provides Na+, Cl-, and free water o used as a basic fluid for maintenance needs o often used to treat hypernatremia (because this solution contains a small amount of Na+, it dilutes the plasma sodium while not allowing it to drop too rapidly)
Hypertonic – hypertonic to plasma
- 5% dextrose in 0% NaCl (D 5 ½ NS) o used to maintain fluid intake
- 10% dextrose in water (D 10 W) o supplies 340 cal/L o used in peripheral parenteral nutrition (PPN)
- 5% dextrose in 0% NaCl (D 5 NS) o used to treat SIADH o can temporarily be used to treat hypovolemia if plasma expander is not available
EQUIPMENT
Pics on PowerPoint
IV equipment (including buretrol) Peripheral venous catheters Midline peripheral catheters Central venous access devices and PICCs Ports
Caring for a PICC line
- Use sterile technique when changing dressings (24 hours after insertion and 3 to 7 days thereafter); also change if soiled or loose
- When accessing the PICC or changing dressings, some facilities require that the patient and nurse wear a mask
- Flush with normal saline or heparin, depending on facility policy
- Avoid BP in the arm with a PICC
- Document: appearance of site, length of external part of catheter, dates of dressing change, flushing frequency and routine, any problems
- Teach patient to avoid strenuous physical activity that can displace the PICC and to cover the site when showering
IV Site Selection
Pic of veins in arms
insertion -frequent dressing changes -inadequate or improper decontamination of hub -inappropriate administration set changes
-other VS changes
Phlebitis -mechanical traumafrom needle or catheter
-chemical trauma from solution
-local, acute tenderness -warmth -slight edema of the vein above the insertion site
-DC infusion immediately -apply warm, moist compresses to the site -avoid further use of the vein -restart infusion in another vein Thrombus -tissue trauma from needle or catheter
-similar s/s to phlebitis -IV fluid flow may cease if clot obstructs needle
-DC infusion immediately -apply warm compresses as ordered -restart IV at another site -DO NOT RUB OR MASSAGE THE AFFECTED AREA Speed shock -too rapid a rate of fluidinfusion into circulation -pounding headache-fainting
-rapid pulse -apprehension -chills -back pain -dyspnea
-use the proper IV tubing -carefully monitor the rate of fluid flow -check the rate frequently for accuracy
Fluid overload -too large a volume of fluid infused into circulation
-engorged neck veins -increased BP -dyspnea
-slow the rate of infusion -notify PCP immediately -monitor VS -carefully monitor rate of fluid flow -check rate frequently for accuracy Air embolus -break in the IV system above the heart level, allowing air in the circulatory system as a bolus
-respiratory distress -increased heart rate -cyanosis -decreased BP -change in LOC
-pinch off catheter or secure system to prevent entry of air -place patient on left side in Trenelenberg -call for immediate assistance -monitor VS and pulse ox
IV MATH!!
ADMINISTERING BLOOD AND BLOOD PRODUCTS
It is the administration of blood or components of blood such as plasma, RBCs, cryoprecipitate, or platelets
Life-threatening complications include:
- anaphylaxis
- hemolytic reaction
- transfusion-related acute lung injury
- circulatory overload
- transmission of infectious diseases
Blood typing and cross-matching must be done first; typing to determine blood type and cross-matching determines if the donor blood is compatible with the patient’s blood
Blood types are:
• A
• B
- AB – universal recipients
- O – universal donor
Rh-negative must receive blood from an Rh-negative donor
Autologous transfusion – transfusion of a patient’s own blood; if they forsee the need for a transfusion, a patient can donate their own blood ahead of time; known as an autottransfusion
Whole blood is rarely given unless massive blood loss has occurred; generally we can give only the component of blood that the patient needs (i. RBCs) so that we don’t put them in fluid overload
PRBCs – packed red blood cells; concentrated RBCs
FFP – fresh frozen plasma
Cryoprecipitate – used for hemophilia or lack of coagulation factors
Platelets
Follow facility policy in regards to blood transfusions
Two licensed practitioners check the blood and patient together prior to infusion
Careful monitoring for the first 15 minutes, then depending on facility policy Transfusion reactions can occur within the first 24 hours or 1 day to several days after the transfusion
Reaction S/S Nursing Activity Allergic reaction -hives -itching -anaphylaxis
-stop transfusion immediately and KVO with normal saline -notify PCP immediately -administer antihistamine parenterally as necessary Febrile reaction: fever -fever -stop transfusion
Ch-39 Lecture - Bhbhbh.
University: Miami Dade College
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